Cisco IOS Software Releases 12.3 T

Table Of Contents

Circuit Emulation over IP

Contents

Prerequisites for Circuit Emulation over IP

Restrictions for Circuit Emulation over IP

Information About Circuit Emulation over IP

Circuit Emulation over IP

Benefits of Circuit Emulation over IP

Adaptive Clocking for Circuit Emulation over IP

Control Lead Configurations

CRC Error Check

Data Protection (Sample Repetition)

Dejitter

Idle Pattern

Interface MIB

Payload Compression for Circuit Emulation over IP

Payload Size

Port Muxing

Signaling for Circuit Emulation over IP

TDM Clock Network Participation

How to Configure Circuit Emulation over IP

Configuring the NM-CEM-4TE1 Card Type

What to Do Next

Configuring the T1/E1 Line

What to Do Next

Creating CEM Channels on the T1/E1 Line

What to Do Next

Configuring the Connection Using the xconnect Command

What to Do Next

Configuring the CEM Channel

Examples

Configuring Port Muxing on a CEM Serial Channel

Configuration Examples for Circuit Emulation over IP

Configuring a T1 CEM Network Module: Example

Configuring a Serial CEM Network Module: Example

Verifying a CEM Network Module Example

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Command Reference

attach (CEM)

cem

cem-group

clear cem

clock mode

clock rate

clock source (CEM)

control-lead sampling-rate

control-lead state

crc-threshold

data-protection

data-strobe

dejitter-buffer

failure

framing (CEM)

idle-pattern

ip dscp

local ip address

local udp port

loopback (CEM)

payload-compression

payload-size

remote udp port

show cem

signaling

xconnect (CEM)

Circuit Emulation over IP

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Circuit Emulation over IP (CEoIP) provides a protocol-independent transport over IP networks. It enables proprietary or legacy applications to be carried transparently to the destination, similar to a leased line. Two network modules—NM-CEM-4TE1 and NM-CEM-4SER—are introduced to provide the CEoIP support.

History for the Circuit Emulation over IP Feature

Release	Modification
12.3(7)T	This feature was introduced.
12.3(7)T1	The failure command was added and the signaling command was modified.
12.4(2)T	The clock source (CEM) and the show cem commands were modified to support enhanced adaptive clocking.
12.4(6)T	The attach port and control lead state commands were added to support port muxing. The clock rate command was updated to support additional baud rates. Support was added for participation in network clocking. Support was added for the IF-MIB on serial CEM network modules.

Finding Support Information for Platforms and Cisco IOS Software Images

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Contents

•Prerequisites for Circuit Emulation over IP

•Restrictions for Circuit Emulation over IP

•Information About Circuit Emulation over IP

•How to Configure Circuit Emulation over IP

•Configuration Examples for Circuit Emulation over IP

•Additional References

•Command Reference

Prerequisites for Circuit Emulation over IP

•The CEoIP feature requires a circuit emulation (CEM) network module (NM) on each end of the connection, either the NM-CEM-4TE1 or the NM-CEM-4SER. You do not need to use the same type of CEM NM on both ends of the connection.

•The CEoIP feature requires 300 KB of flash memory and 1 MB of DRAM in addition to your Cisco IOS software requirements.

Restrictions for Circuit Emulation over IP

•The NM-CEM-4TE1 supports only B8ZS (T1) and HDB3 (E1) line codes.

•E1 lines do not support 56-kbps connections.

•CEoIP software cannot run payload compression for more than 3.088 Mbps per network module.

•If you configure four T1, E1, or serial cables (over 1.544 MB) at the same time on Cisco 2600XM series routers, you cannot turn on the data protection and payload compression features. Also, in framed mode (channelized), you can use up to 60 channels without the data protection and payload compression features on Cisco 2600XM series routers. However, you can turn on the data protection and payload compression feature on one T1/E1.

•There is a limitation on the data protection and payload compression features on Cisco 3660 routers. If you configure four T1, E1, or serial cables on Cisco 3660 routers, you can turn on data protection for up to two T1/E1s. In framed mode, you can use 88 channels.

Information About Circuit Emulation over IP

To configure Circuit Emulation over IP, you should understand the following concepts:

•Circuit Emulation over IP

•Benefits of Circuit Emulation over IP

•Adaptive Clocking for Circuit Emulation over IP

•Control Lead Configurations

•Data Protection (Sample Repetition)

•Dejitter

•Idle Pattern

•Interface MIB

•Payload Compression for Circuit Emulation over IP

•Payload Size

•Port Muxing

•Signaling for Circuit Emulation over IP

•TDM Clock Network Participation

Circuit Emulation over IP

Circuit emulation over IP is an end-to-end service that allows Layer 1 data to be transported transparently through an IP network. Applications that require circuit emulation need the network to provide a constant-rate bit stream. Enterprise customers can use CEoIP with the enhanced adaptive clock to provide a leased-line emulation service to connect a central PBX to one or more remote PBXs. In Figure 1 an existing PBX system with leased T1 or E1 lines is shown in the diagram on the left, and CEoIP is introduced in the diagram on the right. CEoIP introduces the ability to provide an emulation of T1 or E1 leased lines through an IP infrastructure that is transparent to the PBXs.

Figure 1 PBX Application of CEoIP

CEoIP can use adaptive clocking as a means of synchronizing the clock frequencies at the two endpoints. Channel-associated signaling (CAS) transport is provided as an optional feature to allow channelized voice applications. Payload compression is provided as an optional feature to improve bandwidth efficiency, and data protection is provided to reduce the probability of data loss.

CEoIP software supports the following network modules:

•NM-CEM-4SER—A network module with four serial ports. To configure CEoIP software for the NM-CEM-4SER, you must configure the options of the ports. Options include dejitter buffer, payload compression, and payload size.

•NM-CEM-4TE1—A network module with four ports that you can configure as T1 or E1 (where all four ports support the same interface type). To configure CEoIP software for the NM-CEM-4TE1, you must define the card type and then configure the options of the port.

CEoIP can be used by mobile wireless service providers to configure existing IP infrastructure to carry compressed or noncompressed time-division multiplexing (TDM) voice traffic between geographically distributed cell sites and centralized equipment. CEoIP can be used at cell sites to provide asynchronous control of devices at cell sites. Another application can be for Metro Ethernet where CEoIP can provide a T1/E1 leased-line emulation over a packet infrastructure.

Benefits of Circuit Emulation over IP

CEoIP emulates a TDM circuit over a pipe through the IP network so that TDM Circuit-based networks can be migrated to a packet-based network. CEoIP provides a simple migration path to IP-only networks. Examples of solutions that CEoIP integrates with IP include the following:

•Legacy data services

•Legacy video applications

•Satellite data streams

•Radar data streams

•Telemetry for automated industrial environments (for example, power distribution)

•Crypto tunneling for multilevel security

Adaptive Clocking for Circuit Emulation over IP

The adaptive clocking option of CEoIP allows the egress clock to vary by expanding or contracting the clock period from the nominal clock. After you have implemented the clocking feature, the adaptive clocking circuits continuously adjust the selected clock on the basis of the data buffer level. You can implement adaptive clocking on each port independently.

In Cisco IOS Release 12.4(2)T and later releases, the adaptive clocking algorithm is enhanced to provide better adaptive clock accuracy. The clock source command allows one of three adaptive modes to be selected:

•coarse—Specifies the coarse mode. The coarse mode uses the original adaptive clock algorithm and is used when the stability of the master clock derived from the CPE is not guaranteed. This mode is compatible with previous Cisco IOS releases.

•closed-loop—Specifies the closed loop mode. Taking advantage of the fact that a T1 or E1 link uses the same clock in both directions, the adaptive clock algorithm enhancements are used to improve the adaptive clock accuracy. The same clock must be used in both directions for the closed loop mode, and both ends of the CEM must be running a Cisco IOS release that supports the enhanced adaptive clock algorithm. Use the closed loop mode when clock accuracy is required, the master clock from the customer premises equipment (CPE) is of good quality, and the clocks are the same in both directions of the T1 or E1 link.

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Note Do not use the closed loop mode in applications where the clocks are different for the two directions of the T1 or E1 link.

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•open-loop—Specifies the open loop mode. Some of the adaptive clock algorithm is used, but this mode does not require the clocks to be the same in both directions. This mode is compatible with previous Cisco IOS releases and is the default mode if no keyword is specified. Use the open loop mode when the master clock from the CPE is of good quality, but the clocks are not the same in both directions of the T1 or E1 link.

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Note The NM-CEM-4SER does not support the enhanced adaptive clock accuracy feature introduced in Cisco IOS Release 12.4(2)T.

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Control Lead Configurations

CEoIP software supports the monitoring and transport of serial interface control leads.

CRC Error Check

CRC error checking can be disabled on specific serial modules so that the CEM payload is passed on in spite of bit errors. CEM can tolerate a low error rate without losing its synchronization. The ability to disable CRC error checking makes CEM more robust on lossy IP networks.

Modules that support disabling of CRC error checking include the NM-4T, WIC-2T, VWIC-2MFT-DI, WIC-1DSU-56K4, VWIC-1MFT-T1, VWIC-1MFT-E1, VWIC-2MFT-T1, VWIC-2MFT-E1, VWIC-2MFT-T1-DI, and the HWIC-4T.

Data Protection (Sample Repetition)

The data protection option, also known as sample repetition, reduces the probability of errors due to packet loss by sending each sample twice, in two different IP packets. Data protection consumes more bandwidth than standard transmission, but you can minimize the amount of traffic with payload compression. This feature is disabled by default.

Dejitter

The dejitter buffer size determines the ability of the emulated circuit to tolerate network jitter. The dejitter buffer in CEoIP software is configurable up to 500 milliseconds; the maximum amount of network jitter that CEoIP can tolerate is plus or minus 250 milliseconds.

Idle Pattern

The idle pattern option specifies the idle pattern to transmit when the circuit goes down. You can specify a maximum of 64 bits with two 32-bit patterns for the NM-CEM-4SER and eight 8-bit patterns for the NM-CEM-4TE1.

Interface MIB

The Interface MIB (IF-MIB) is available for CEM channels for monitoring link status with the linkDown and linkUp MIB objects. The IF-MIB is supported only on serial CEM network modules.

Payload Compression for Circuit Emulation over IP

The payload compression option minimizes the amount of bandwidth that traffic consumes. It compresses the transmission of any repetitive data pattern (idle code, HDLC flags, and so on) to increase the efficiency of the solution across the network.

With CEoIP software, you can adjust the size (in bytes) of the payload for the IP packet to configure efficiency as opposed to packetization. Larger payloads provide more efficiency but increase the delay. With smaller packets, the overhead of the header increases. Payload compression is disabled by default.

Payload Size

Payload size is the number of bytes put into each IP packet. This parameter impacts packetization delay and efficiency. Configure a high payload size to increase packetization delay and efficiency. A smaller payload size reduces packetization delay and efficiency.

Port Muxing

The port muxing capability allows data directed to the same destination from different serial ports to be multiplexed into a single CEM channel. Port muxing reduces operating overhead because only one port requires management.

All ports in a muxed group must be of the same type, such as all RS232 ports, or all RS530 ports; they must be of the same "polarity" (DCE or DTE); and they must all belong to the same clock domain.

When ports are participating in a muxed group, compression/data protection will not be supported.

Signaling for Circuit Emulation over IP

CEoIP software supports the transport of channel-associated signaling (CAS) bits in channelized T1/E1 mode. This option extracts incremental signaling information and sends that information in separate packets.

TDM Clock Network Participation

Allows the CEM channel to participate in a TDM clock network and to function both as a clock slave and a clock master. The adaptive clock recovered from the CEM channel can be passed to other network clock-capable modules, such as the VWIC. The clock coming in from other T1/E1 lines can be used to start the clocks on the CEM. The CEM, likewise, can trigger clocks on T1/E1 links.

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Note The Cisco 2600XM platform requires the AIM-VOICE-30, AIM-ATM, or AIM-ATM-VOICE-30; and the Cisco 3660 platform, requires the MIX-3660-64 for this feature.

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How to Configure Circuit Emulation over IP

This section documents the tasks for configuring the two network modules introduced to support CEoIP: NM-CEM-4TE1 and NM-CEM-4SER.

•Configuring the NM-CEM-4TE1 Card Type

•Configuring the T1/E1 Line

•Creating CEM Channels on the T1/E1 Line

•Configuring the Connection Using the xconnect Command

•Configuring the CEM Channel

•Configuring Port Muxing on a CEM Serial Channel

To configure an NM-CEM-4TE1, start with the "Configuring the NM-CEM-4TE1 Card Type" section.

To configure an NM-CEM-4SER, go directly to the "Configuring the Connection Using the xconnect Command" section.

Configuring the NM-CEM-4TE1 Card Type

Perform this task to configure the card type for the four-port T1 or E1 network module that supports CEoIP (NM-CEM-4TE1). All the ports must be set to the same transmission mode, either T1 or E1.

This task does not apply to the NM-CEM-4SER.

SUMMARY STEPS

1. enable

2. configure terminal

3. card type {t1 | e1} slot

4. end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. •Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	card type {t1 | e1} slot Example: Router(config)# card type t1 1	Configures the card type by specifying the transmission mode for the ports on the network module. •All four ports on the CEoIP T1/E1 network module must operate in the same mode. •Use the t1 or e1 keyword to specify the transmission mode for all four ports. Note This command is entered only once, and changes do not take effect unless the reload command is used or the router is rebooted.
Step 4	end Example: Router(config)# end	Exits global configuration mode and returns to privileged EXEC mode.

What to Do Next

Go to the "Configuring the T1/E1 Line" section to continue configuring CEoIP on an NM-CEM-4TE1.

Configuring the T1/E1 Line

Perform this task to configure the T1 or E1 line.

This task does not apply to the NM-CEM-4SER.

SUMMARY STEPS

1. enable

2. configure terminal

3. controller {t1 | e1} slot/port

4. framing {esf | sf | unframed}
or
framing {crc4 | no-crc4 | unframed}

5. clock source {internal | line | adaptive channel-number [closed-loop | open-loop | coarse]}

6. cablelength {long attenuation | short length}

7. crc-threshold value

8. description text

9. loopback{local {line | payload} | network}

10. end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. •Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	controller {t1 | e1} slot/port Example: Router(config)# controller t1 1/0	Enters controller configuration mode. •Use the slot and port arguments to specify the slot number and port number to be configured.
Step 4	framing {esf | sf | unframed} or framing {crc4 | no-crc4 | unframed} Example: Router(config-controller)# framing esf Example: Router(config-controller)# framing crc4	(Optional) Configures the framing format for a T1 or E1 port to synchronize the port and the attached device. T1 Port Framing Options •Use the esf keyword to specify Extended Superframe as the T1 framing type. •Use the sf keyword to specify the Superframe (also commonly called D4 framing) as the T1 framing type. This is the default. E1 Port Framing Options •Use the crc4 keyword to specify the G.704 standard with the optional CRC4 mechanism defined in time slot zero (0) enabled as the E1 framing type. This is the default. •Use the no-crc4 keyword to specify the G.704 standard with the optional CRC4 mechanism defined in time slot zero (0) disabled as the E1 framing type. T1 or E1 Port Framing Options •Use the unframed keyword to specify the unchannelized mode of framing. Note If you do not configure framing, the framing on the customer premises equipment (CPE) devices on each end of the connection must match.
Step 5	clock source {internal | line | adaptive channel-number [closed-loop | open-loop | coarse]} Example: Router(config-controller)# clock source adaptive 6	Configures the clock source for a T1 or E1 port. •Use the internal keyword to specify that the port transmit clock is derived from the time-division multiplexing (TDM) bus backplane clock, if one exists in the router, or from the onboard oscillator on the network module. •Use the line keyword to specify that the port transmit clock is derived from the receive clock on the same port. •Use the adaptive keyword to specify that the port transmit clock is locally synthesized on the basis of the average data content of the dejitter buffer of one of the channels on this port. If the adaptive keyword is selected, use the channel-number argument to specify the channel whose dejitter buffer is to be used to synthesize the transmit clock of the port. –Use the closed-loop keyword to specify that the enhanced adaptive clock algorithm is used to improve the adaptive clock accuracy. –Use the open-loop keyword to specify that some of the enhancements to the adaptive clock algorithm are used to improve the adaptive clock accuracy. –Use the coarse keyword to specify that the original adaptive clock algorithm is used. Note The closed-loop, open-loop, and coarse keywords are supported only in Cisco IOS Release 12.4(2)T and later releases.
Step 6	cablelength {long attenuation | short length} Example: Router(config-controller)# cablelength long -15db	(Optional) Specifies the line build-out characteristics of the internal CSU on a T1 port. •Use the long keyword to specify that the signal characteristics are set for a long cable length. If the long keyword is selected, use the attenuation argument to specify the T1 signal attenuation. •Use the short keyword to specify that the signal characteristics are set for a short cable length. If the short keyword is selected, use the length argument to specify the T1 cable length. Note This command does not apply to an E1 port.
Step 7	crc-threshold value Example: Router(config-controller)# crc-threshold 512	(Optional) Configures the number of cyclical redundancy check (CRC) errors in one second that result in the second being declared a Severely Errored Second (SES). •Use the value argument to specify the number of CRC errors. Range is from 0 to 3000. Default is 320. Note This command does not apply to an E1 port.
Step 8	description text Example: Router(config-controller)# description T1 line to 3rd floor PBX	(Optional) Specifies a text description of the port.
Step 9	loopback {local {line | payload}| network} Example: Router(config-controller)# loopback network	(Optional) Creates a loopback from a T1 or E1 port. •Use the local keyword to create a loopback where the information from a locally-attached CPE is transmitted back to the locally-attached CPE. –If the local keyword is selected, use the line keyword to create a full physical-layer loopback of all bits, including data and framing. –If the local keyword is selected, use the payload keyword to create a loopback of the data in the individual time slots only. In this mode, framing bits are terminated on entry and regenerated on exit instead of being looped back. This mode is not available if the port is configured for framing unframed. •Use the network keyword to create a loopback where the data received over the network from a remotely-attached CPE is transmitted back to the remotely-attached CPE.
Step 10	end Example: Router(config-controller)# end	Exits controller configuration mode and returns to privileged EXEC mode.

What to Do Next

Go to the "Creating CEM Channels on the T1/E1 Line" section to continue configuring CEoIP on an NM-CEM-4TE1.

Creating CEM Channels on the T1/E1 Line

Perform this task to create CEM channels on the T1 or E1 line.

This task does not apply to the NM-CEM-4SER.

SUMMARY STEPS

1. enable

2. configure terminal

3. controller {t1 | e1} slot/port

4. cem-group group-number {unframed | timeslots timeslot [speed {56 | 64}]}

5. end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. •Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	controller {t1 | e1} slot/port Example: Router(config)# controller t1 1/0	Enters controller configuration mode. •Use the slot and port arguments to specify the slot number and port number to be configured.
Step 4	cem-group group-number {unframed | timeslots timeslot [speed {56 | 64}]} Example: Router(config-controller)# cem-group 6 timeslots 1-4,9,10 speed 64	Creates a circuit emulation channel from one or more time slots of a T1 or E1 line of an NM-CEM-4TE1. •The group-number keyword identifies the channel number to be used for this channel. For T1 ports, the range is 0 to 23. For E1 ports, the range is 0 to 30. •Use the unframed keyword to specify that a single CEM channel is being created including all time slots and the framing structure of the line. •Use the timeslots keyword and the timeslot argument to specify the time slots to be included in the CEM channel. The list of time slots may include commas and hyphens with no spaces between the numbers. –Use the speed keyword to specify the speed of the channels by specifying the number of bits of each time slot to be used. This keyword applies only to T1 channels.
Step 5	end Example: Router(config-controller)# end	Exits controller configuration mode and returns to privileged EXEC mode.

What to Do Next

Go to the "Configuring the Connection Using the xconnect Command" section to continue configuring CEoIP on an NM-CEM-4TE1.

Configuring the Connection Using the xconnect Command

Perform this task to create a connection using the xconnect command.

This task applies to configuring CEoIP on both the NM-CEM-4TE1 and the NM-CEM-4SER.

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Note To properly configure the CEoIP feature, two CEoIP network modules must use the same UDP port number to communicate.

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SUMMARY STEPS

1. enable

2. configure terminal

3. cem slot/port/channel

4. xconnect remote-ip-address virtual-connect-ID encapsulation encapsulation-type

5. local ip address ip-address

6. local udp port port

7. remote udp port port

8. end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. •Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	cem slot/port/channel Example: Router(config)# cem 3/1/0	Enters CEM configuration mode to configure CEM channels. •Use the slot argument to specify the slot number in which the network module is installed. •Use the port argument to specify the port number of the CEM channel to be configured. •Use the channel argument to specify the CEM channel number to be configured. For a serial channel, enter zero. For a T1 or E1 channel, enter the channel number defined in the cem-group command (see the "Creating CEM Channels on the T1/E1 Line" section).
Step 4	xconnect remote-ip-address virtual-connect-ID encapsulation encapsulation-type Example: Router(config-cem)# xconnect 10.2.0.1 0 encapsulation udp	Creates one end of a connection between two CEM network modules and enters xconnect configuration mode. •Use the remote-ip-address argument to specify the IP address of an interface (regular or loopback) on the destination router. •Set the virtual-connect-ID argument to zero. Note Currently the only supported encapsulation type is UDP.
Step 5	local ip address ip-address Example: Router(config-cem-xconnect)# local ip address 10.2.0.2	Configures the IP address of an interface (regular or loopback) on the source router. Note The local IP address must be the same as the remote IP address (at the other side) configured in the xconnect command.
Step 6	local udp port port Example: Router(config-cem-xconnect)# local udp port 15901	Specifies the User Datagram Protocol (UDP) port number of the local CEM channel. Note The number of the local UDP port of a CEM channel must be the same as the number of the remote UDP port of the CEM channel at the other end of the connection.
Step 7	remote udp port port Example: Router(config-cem-xconnect)# remote udp port 15902	Specifies the UDP port number of the remote CEM channel. Note The number of the remote UDP port of a CEM channel must be the same as the number of the local UDP port of the CEM channel at the other end of the connection.
Step 8	end Example: Router(config-cem-xconnect)# end	Exits xconnect configuration mode and returns to privileged EXEC mode.

What to Do Next

This task must be repeated on the other CEM network module. Each end of the CEM connection must be configured identically to allow traffic to pass between the network modules. When both network modules have been configured, go to the "Configuring the CEM Channel" section.

Configuring the CEM Channel

Perform this task to configure the CEM T1/E1 or serial channel.

This task applies to both the NM-CEM-4TE1 and the NM-CEM-4SER.

SUMMARY STEPS

1. enable

2. configure terminal

3. cem slot/port/channel

4. clock rate rate

5. clock mode {normal | split}

6. clock source {internal | loop | adaptive}

7. payload-size size

8. dejitter-buffer size

9. control-lead sampling-rate rate

10. control-lead state {active | fail} output-lead {on | off | follow} [{local | remote} input-lead]

11. data-strobe input-lead {on | off}

12. idle-pattern {pattern | length pattern1 [pattern2]

13. failure {activation | deactivation} msec

14. signaling [on-hook-pattern] [off-hook-pattern] [msec]

15. payload-compression

16. data-protection

17. ip dscp [dscp-value]

18. ip tos tos

19. ip precedence precedence

20. loopback {local | network}

21. end

22. show cem {slot/port/channel | summary}

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. •Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	cem slot/port/channel Example: Router(config)# cem 3/1/0	Enters CEM configuration mode to configure CEM channels. •Use the slot argument to specify the slot number in which the network module is installed. •Use the port argument to specify the port number of the CEM channel to be configured. •Use the channel argument to specify the CEM channel number to be configured. For a serial channel, enter zero. For a T1 or E1 channel, enter the channel number defined in the cem-group command (see the "Creating CEM Channels on the T1/E1 Line" section).
Step 4	clock rate rate Example: Router(config-cem)# clock rate 38400	(Optional) For serial channels only. Specifies the nominal bit rate of a serial CEM channel. •Use the rate argument to specify the data rate of the channel, in bps. Default is 64000.
Step 5	clock mode {normal | split} Example: Router(config-cem)# clock mode split	(Optional) For serial channels only. Specifies the clock mode of a serial CEM channel. •Use the normal keyword to specify that the DCE provides both the Receive Clock (RxC) and the Transmit clock (TxC) to the attached DTE. •Use the split keyword to specify that the DCE provides the Receive Clock (RxC) to the attached DTE and that the DTE provides the external Transmit Clock (XTC or TT) to the DCE. Note Depending on the serial cable attached to the port, the port is automatically configured as either a DCE or a DTE.
Step 6	clock source {internal | loop | adaptive} Example: Router(config-cem)# clock source loop	(Optional) Configures the clock source for a serial CEM channel. •This step applies only to configuring serial channels. For information about configuring the clock source for T1 or E1 ports, see the "Configuring the T1/E1 Line" section. •Use the internal keyword to specify that the clock(s) provided by the network module to the CPE is derived from the TDM bus backplane clock, if one exists in the router, or from the onboard oscillator on the network module. •Use the loop keyword to specify that the clock provided by the network module to the attached CPE is derived from the clock received on the same port from the attached CPE. •Use the adaptive keyword to specify that the clock(s) provided by the network module to the CPE is locally synthesized based on the average data content of the local dejitter buffer. Note The loop keyword is valid only when the clock mode split command is configured.
Step 7	payload-size size Example: Router(config-cem)# payload-size 512	(Optional) Specifies the number of bytes encapsulated into a single IP packet. •Use the size argument to specify the number of bytes included in the payload of each packet. Default is 32 for a serial CEM channel. •For more information about T1 and E1 default values, see the payload-size command in the Cisco IOS Interface and Hardware Component Command Reference, Release 12.4.
Step 8	dejitter-buffer size Example: Router(config-cem)# dejitter-buffer 80	(Optional) Specifies the size of the dejitter buffer used to compensate for the network filter. •Use the size argument to specify the size of the buffer, in milliseconds. Default is 60.
Step 9	control-lead sampling-rate rate Example: Router(config-cem)# control-lead sampling-rate 10	(Optional) For serial channels only. Specifies the sampling rate of input control leads on a serial CEM channel. •Use the rate argument to specify the frequency with which the control leads are sampled, in samples per second. Default is 0. Note Control lead update packets are independent of the data packets from the same channel.
Step 10	control-lead state {active | fail} output-lead {on | off | follow} [{local | remote} input-lead] Example: Router(config-cem)# control-lead state active rts follow remote cts	(Optional) For serial channels only. Specifies the state of each output control lead on a serial CEM channel. •Use the active keyword to specify the state of the control lead when the connection is active. •Use the fail keyword to specify the state of the control lead when the connection has failed. •Use the output-lead argument to specify the name of the control lead. •Use the on keyword to specify that the control lead is permanently asserted. •Use the off keyword to specify that the control lead is permanently not asserted. •Use the follow keyword to specify that the control lead is to follow any changes in the state of an input control lead specified by the local or remote keywords and the input-lead argument. •Use the input-lead argument to specify the name of the local or remote control lead to follow. Note Control lead update packets are independent of the data packets for the same channel. Note The control-lead sampling-rate parameter must be set to nonzero in order for this feature to operate.
Step 11	data-strobe input-lead {on | off} Example: Router(config-cem)# data-strobe dtr on	(Optional) For serial channels only. Specifies that an input control lead is to be monitored and data is packetized and sent only when the specified control lead is in the specified state. •Use the input-lead argument to specify the input control lead to be monitored to determine whether input data is to be packetized. •Use the on keyword to specify that data packets are to be sent from this CEM channel only when the specified input lead is asserted. •Use the off keyword to specify that data packets are to be sent from this CEM channel only when the specified input lead is not asserted. •Use this command to save bandwidth when the attached CPE is inactive. Note Control lead update packets are still sent even if data packets are withheld.
Step 12	Cisco NM-CEM-4SER idle-pattern length pattern1 [pattern2] Cisco NM-CEM-4TE1 idle-pattern pattern1 Example: Cisco NM-CEM-4SER Router(config-cem)# idle-pattern 53 0x12345678 0x87654321 Cisco NM-CEM-4TE1 Router(config-cem)# idle-pattern 0x66	(Optional) Defines the idle data pattern to send to the attached CPE when packets are lost or the dejitter buffer experiences an under-run condition. For serial CEM channels: •A bit pattern up to 64 bits long may be specified. •Use the length argument to specify the total length of the repeating bit pattern. Default is 8 bits. •Use the pattern1 argument to specify up to 32 bits of the least significant bits of the idle data pattern, in hex notation. Default is 0xFF. •Use the pattern2 argument to specify the most significant bits of the idle data pattern, in hex notation. If the length argument is 32 bits or less, this argument is not permitted. For T1 or E1 CEM channels: •An eight 8-bit idle data pattern is specified.
Step 13	failure {activation | deactivation} msec Example: Router(config-cem)# failure activation 1000	(Optional) Specifies a time period before a circuit emulation (CEM) connection enters, or recovers from, a failed state. •Use the activation keyword to specifiy how long the software will wait for the detection of a failure of a CEM connection until the CEM channel enters the failed state. •Use the deactivation kewyord to specifify how long the software will wait from the detection of a repair to the CEM connection until the CEM channel is returned to an active (up) state. •Use the time argument to specify the failure activation or deactivation time in milliseconds. The valid range is 50 to 60000. Default is 2000. Any value entered is rounded up to the next multiple of 50 milliseconds.
Step 14	signaling [on-hook-pattern] [off-hook-pattern] [msec] Example: Router(config-cem)# signaling	(Optional) For framed T1 or E1 data channels only. Enables the transport of channel-associated signaling (CAS) bits.
Step 15	payload-compression Example: Router(config-cem)# payload-compression	(Optional) Enables payload compression on a CEM channel. Note Enabling payload compression adds a delay equal to one packet time.
Step 16	data-protection Example: Router(config-cem)# data-protection	(Optional) Enables data protection by transmitting each data bit twice, once in each of two consecutive data packets. •Use the data-protection command to protect transmissions from the effects of lost IP packets. Caution Use this command carefully because it increases the network bandwidth used by the CEM connection.
Step 17	ip dscp [dscp-value] Example: Router(config-cem)# ip dscp 36	(Optional) Configures the IP differentiated services code point (DSCP) for packets originating from this CEM channel. •Use the optional dscp argument to specify the value placed in the DSCP field of IP packets originating from this channel. Default is 46. Note If DSCP is configured, the ip tos and ip precedence commands are not available because they are mutually exclusive.
Step 18	ip tos tos Example: Router(config-cem)# ip tos 11	(Optional) Configures the IP type of service (ToS) bits for the CEM channel. •Use the tos argument to specify the value placed in the ToS field of IP packets originating from this channel. Default is 5. Note If DSCP is configured using the ip dscp command, the ip tos command is not available because these commands are mutually exclusive.
Step 19	ip precedence precedence Example: Router(config-cem)# ip precedence 7	(Optional) Configures the IP precedence bits for the CEM channel. •Use the precedence argument to specify the value placed in the precedence field of IP packets originating from this channel. Default is 0. Note If DSCP is configured using the ip dscp command, the ip precedence command is not available because these commands are mutually exclusive.
Step 20	loopback {local | network} Example: Router(config-cem)# loopback network	(Optional) Creates a loopback from a CEM serial channel. •Use the local keyword to create a loopback where the information from a locally-attached CPE is transmitted back to the locally-attached CPE. •Use the network keyword to create a loopback where the data received over the network from a remotely-attached CPE is transmitted back to the remotely-attached CPE. Note For configuring a loopback on a T1 or E1 port, see the "Configuring the T1/E1 Line" section.
Step 21	end Example: Router(config-cem)# end	Exits CEM configuration mode and returns to privileged EXEC mode.
Step 22	show cem {slot/port/channel | summary} Example: Router# show cem summary	Displays CEM statistics.

Examples

The following example shows partial output from the show cem command using the summary keyword:

Router# show cem summary

cem summary

CSTATE: CEM state

LSTATE: line state

OSTATE: operational state

PSIZE: payload-size

PCOMP: payload-compression

DPROT: data-protection

CEM    CSTATE    LSTATE     OSTATE          PSIZE    PCOMP      DPROT

----------------------------------------------------------------------

2/0/0   shutdown   up     config-incomplete   256    disabled   disabled 

2/1/0   shutdown   up     config-incomplete   256    disabled   disabled 

2/2/0   shutdown   up     config-incomplete   256    disabled   disabled 

2/3/0   shutdown   up     config-incomplete   256    disabled   disabled 

4/0/1   up         up     active              96     enabled    disabled 

4/0/2   up         up     active              96     enabled    disabled 

4/0/3   up         up     active              96     enabled    disabled 

4/0/4   up         up     active              96     enabled    disabled 

4/0/5   up         up     active              96     enabled    disabled 

4/0/6   up         up     active              96     enabled    disabled 

4/0/7   up         up     active              96     disabled   disabled 

4/0/8   up         up     active              96     disabled   disabled 

4/0/9   up         up     active              96     disabled   disabled 

4/0/10  up         up     active              96     disabled   disabled 

Configuring Port Muxing on a CEM Serial Channel

Perform this task to configure port muxing on a CEM serial channel, routing data from multiple ports through a single channel. Port Muxing reduces operating overhead, requiring management of a single port rather than several.

SUMMARY STEPS

1. enable

2. configure terminal

3. cem slot/port/channel

4. attach port

5. end

Detailed Steps

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. •Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	cem slot/port/channel Example: Router(config)# cem 3/1/0	Enters CEM configuration mode to configure CEM channels. •Use the slot argument to specify the slot number in which the network module is installed. •Use the port argument to specify the port number of the CEM channel to be configured. •Use the channel argument to specify the CEM channel number to be configured. For a serial channel, enter zero. For a T1 or E1 channel, enter the channel number defined in the cem-group command (see the "Creating CEM Channels on the T1/E1 Line" section).
Step 4	attach port Example: Router(config-cem)# attach 1	Attaches slave ports to a master port for port muxing.
Step 5	end Example: Router(config-cem)# end	Exits CEM configuration mode and returns to privileged EXEC mode.
Step 6	show cem {slot/port/channel | summary} Example: Router# show cem summary	Displays CEM statistics.

Configuration Examples for Circuit Emulation over IP

This section provides the following configuration examples:

•Configuring a T1 CEM Network Module: Example

•Configuring a Serial CEM Network Module: Example

•Verifying a CEM Network Module Example

Configuring a T1 CEM Network Module: Example

The following example shows a basic configuration of a T1 network module to configure the CEoIP feature.

card type t1 0

controller t1 4/0

 cem-group 6 timeslots 1-4,9,10 speed 64

 framing esf

 linecode b8zs

 clock source adaptive 6

 cablelength long -15db

 crc-threshold 512

 description T1 line to 3rd floor PBX

 loopback network

 no shutdown

 exit

cem 2/1/6

 xconnect 10.2.0.1 0 encapsulation udp

 local ip address 10.2.0.9 

 local udp port 15901

 remote udp port 15902

 payload-size 512

 dejitter-buffer 80

 signaling

exit

Configuring a Serial CEM Network Module: Example

The following example shows a basic configuration of a CEM serial channel to configure the CEoIP feature. Each end of the CEM connection must be configured before the CEM channel is configured.

Serial CEM Network Module 1

cem 2/0/0

 xconnect 10.3.0.1 0 encapsulation udp

 local ip address 10.3.0.9 

 local udp port 15901

 remote udp port 15902

 end

Serial CEM Network Module 2

cem 2/1/0

 xconnect 10.3.0.9 0 encapsulation udp

 local ip address 10.3.0.1 

 local udp port 15902

 remote udp port 15901

 end

Serial Channel Configuration

cem 2/0/0

 clock rate 38400

 clock mode split

 clock source loop

 payload-size 512

 dejitter-buffer 80

 control-lead sampling-rate 10

 control-lead state active rts follow remote cts

 data-strobe dtr on

 idle-pattern 53 0x12345678 0x87654321

 payload-compression

 data-protection

 ip dscp 36

 loopback network

 end

Verifying a CEM Network Module Example

The folowing example displays the status of a configured CEM network module. This exmaple uses the show cem command to monitor the configuration, status and performance of a particular CEM channel.

Router# show cem 4/1/0

cem info

cem 4/1/0 is up

Line state is up

Operational state is active

Near end ip address: 172.31.28.2, udp port: 15901

Far end ip address: 172.31.28.10, udp port: 15901

IP payload size: 512

IP dscp : 0x28

Idle pattern length: 8 , Idle Pattern: 0xFF

Payload compression is disabled

Data protection is disabled

Dejitter buffer size is 60 ms

Channel clock rate is 2048000 bps

Physical interface is E1 unframed

Ingress packets: 32505156, dropped: 0, overruns: 0

Egress packets: 32505158, dropped: 637, lost pkts: 0

Egress out of sequence pkts: 0

Egress overruns: 16, underruns: 244

Egress corrupt pkts rcvd: 0

30 second ingress rate 2050321 bits/sec, 500 packets/sec

30 second egress rate 2050184 bits/sec, 500 packets/sec

Tx interrupts: 32504249

Reorder queue flush: 0, visited: 0, max wait window: 0

Network jitter max: 8 ms, average: 1 ms, min: 0 ms

Adaptive clock ppm correction is 2 tracking

Event history: 0x00230058

Pkts dropped by burst limit: 0

Global stats for slot 4

************************

Egr free buf: 255

Egr host overruns: 0

Egr unknown dest count: 0

Last unknown dest ip : 0.0.0.0, port: 0

Last unknown dest src ip : 0.0.0.0, port: 0

Egr process switched: 0

Egr oos: 0

Egr unknown src count: 0, last unknown src ip: 0.0.0.0, port: 0

Ingr overruns: 0

NM cpu: 53.56 53.51 53.45 53.54

Table 1provides a listing and description of all of the fields displayed by the show cem command. For each line of the display, the middle column of the table indicates whether that line of the display applies to a serial CEM (S), a T1/E1 CEM (TE), or both.

Table 1 show cem Command Output Display

Display Field	Line Type	Description
cem 1/3/1 is up	S, TE	A CEM channel may be either up, down, or shutdown. The channel is up when it is receiving valid packets from a source CEM channel. The channel is down when it is receiving no packets; i.e., the de-jitter buffer is empty. The channel is shutdown when it has been administratively shut down
Line state is up	S, TE	A line state may be either up or down. A T1/E1 line is down when it is experiencing a physical layer failure such as LOS, OOF, AIS, etc.A serial line is down when no cable is attached to the port. Otherwise, the line is up.
Operational state is active	S, TE	The operational state of a CEM channel may be either config-incomplete, enabled, config-mismatch, or active. A CEM channel is in the config-incomplete state if any of the following conditions is true: •an xconnect is not defined •a local IP address is not defined •a local UDP port is not defined •a remote UDP port is not defined •the CEM channel is administratively shut down. If none of the previous conditions is true, but the CEM channel is receiving no packets from the remote side, the channel is in the enabled state. If packets are arriving from the remote side but with a different payload size, data protection setting, or compression setting, the channel is in the config-mismatch state. Otherwise, the channel is active.
Near end ip address: 30.30.30.1, udp port: 16131	S, TE	The local ip addr used to identify the near end (or source router) of a CEM connection must be the same as the remote ip address (specified above) used to identify the CEM channel at the other end of the CEM connection. If there are multiple CEM connections originating on the same router, they may share the local IP address provided that each connection uses a unique UDP port number
Far end ip address: 40.40.40.1, udp port: 16200	S, TE	The IP address of the remote router. The remote udp port of a CEM channel must be the same as the local udp port of the CEM channel at the other end of the CEM connection.
IP payload size: 64	S, TE	Indicates the nominal bit rate of a serial CEM channel. The actual bit rate may be slightly different depending on whether adaptive clocking is used. See the clock source command for more details.
IP dscp : 0x2E	S, TE	This line is displayed only if DSCP is enabled.
IP dscp is not specified	S, TE	This line is displayed only if DSCP is disabled.
IP prec/tos (tos byte): 0xA0	S, TE	This line is displayed only if DSCP is disabled. Indicates the value specified in the precedence field of the ip precendence command for IP packets originating from this channel and the "type of service" (ToS) bits for the channel. The specified ToS is used in the ToS field of IP packets originating from this channel.
Idle pattern length: 8 , Idle Pattern: 0xFF	S, TE	Indicates the signaling pattern for the transport of Channel Associated Signaling (CAS) bits. It is also used to specify the signaling state for each timeslot of a failed CEM channel. Applies only to framed T1 or E1 data channels.
Payload compression is disabled	S, TE	Indicates whether payload compression is configured on the channel. If payload compression is enabled, the CPU is limited to performing payload compression on an aggregate data load of 3 Mbps per network module. Software prevents compression from being enabled on a channel if the resulting aggregate data load to be compressed would exceed 3 Mbps.
Data protection is disabled	S, TE	Indicates whether data protection is enabled or disabled. Thus, each packet contains: •N payload bytes that are repeated from the previous packet, and •N new payload bytes where N is the number of payload bytes specified in the payload-size command. Consequently, when the data protection feature is enabled, the actual payload size of each packet is double the value specified in the payload-size command. Data protection ensures that no data bits are lost in the event of the loss of a single packet. However, data bits are lost if two or more consecutive packets are lost.
Dejitter buffer size is 60 ms	S, TE	Indicates the configured dejitter buffer size. CEM uses a de-jitter buffer at the destination port and holds data in the de-jitter buffer long enough to ensure that the next packet will have arrived before it needs to be played out. The amount of time that the data must be held in the de-jitter buffer is a function of the worst-case delay variation that the packets experience in the network. The de-jitter buffer size determines the connection's ability to tolerate network delay variation. The size of the buffer is specified using the dejitter-buffer command. When a connection is first established (or following any de-jitter buffer under-run), data arriving from the remote side of the connection is held in the de-jitter buffer until it is at least half-full. Then, data playout to the attached CPE is started. Thus, the average delay introduced by the de-jitter buffer is equal to one half the configured size of the de-jitter buffer.
Channel clock rate is 128000 bps	S, TE	Indicates the nominal bit rate of a serial CEM channel. The actual bit rate may be slightly different depending on whether adaptive clocking is used. See the clock source command for more details. For a T1/E1 CEM channel, the clock rate is determined by the definition of the CEM channel and is implicitly defined by the number of timeslots used in the CEM channel, as specified in the cem-group command
Clock source is adaptive	S	Indicates how the clock source is defined. For serial CEM channels the clock source command is used. For a T1 or E1 CEM channel the clock source is defined as part of the T1/E1 controller configuration.
Clocking mode is normal	S	Indicates the clocking mode for serial CEM channels as set with the clock mode command. For T1 or E1 CEM channel the clock mode is defined as part of the T1/E1 controller configuration.
Loopback mode is disabled	S	Indicates whether a loopback is configured on the serial interface. not applicable to T1 or E1 lines.
Control lead sampling rate is 0 per second	S	Indicates the sampling rate of input control signals for serial CEM channels. There are no control signals defined on a T1 or E1 channel.
Output control lead states: Active template •cts on •dsr follow remote dtr •dcd on •tm on •ri off Fail template •cts off •dsr off •dcd off •tm off •ri off	S	Indicates the state of each output control signal for serial CEM channels as specified with the control lead state command. There are no control signals defined on a T1 or E1 channel.
Data strobe is not configured	S	Indicates whether an input control signal for monitoring valid data has been configured. If a data strobe is specified, data is packetized and sent to the other end ONLY when the specified control signal is in the specified state. When the specified control signal is NOT in the specified state, input data is ignored and no data packets are sent across the network for this channel. This capability is used to save bandwidth when the attached CPE is inactive.
Signaling is disabled	TE	Indicates whether signaling for the transport of Channel Associated Signaling (CAS) bits is configured for framed T1 or E1 data channels.
Physical interface is T1 channelized	TE	The physical interface may be one of: - T1 channelized - T1 unframed - E1 channelized - E1 unframed
Physical interface is RS449 DCE	S	The serial physical interface is determined by the type of cable attached. Refere to the hardware documentation for the netwrok module for valid cable types.
Ingress packets: 215513, dropped: 0, overruns: 0	S,TE	Ingress packets is the number of packets created and sent into the network. Ingress packets dropped is the number of ingress packets that were discarded because the PCI bus to the host CPU was too busy. Ingress overruns is the number of times one or more packets were discarded because the network module's CPU was too busy to process the ingress packets.
Egress packets: 12190, dropped: 0, lost pkts: 0	S,TE	Egress packets is the number of packets received from the network and sent to the attached CPE. Egress packets dropped is the number of valid egress packets that were received but were dropped for any reason (egress de-jitter buffer overflow, lack of egress data clock, etc.) Egress lost pkts is the number of egress packets that were never received as determined by a gap in the sequence numbers of the arriving packets.
Egress out of sequence pkts: 0	S, TE	This is the number of egress packets received out of order as determined by the sequence numbers of the arriving packets.
Egress overruns: 0, underruns: 0	S, TE	Egress overruns is the number of times the egress de-jitter buffer overflowed. Egress underruns is the number of times the egress de-jitter buffer experienced an under-run.
Egress corrupt pkts rcvd: 0	S, TE	This is the number of egress packets received but discarded because the CEoIP header on the packet was found to be inconsistent or corrupt.
30-second ingress rate 128034 bits/sec, 250 packets/sec	S, TE	This is the ingress data rate of the most-recent 30 seconds, in bits/second and in packets/second, measured relative to the local oscillator. The packet rate is measured, but only the integer portion of the measurement is shown. The packets counted include the data packets as well as any control signal update packets or any CAS signaling packets. The bit rate is not measured independently. It is calculated from the measured packet rate. The calculation assumes that all packets have the same payload size as the data packets. In fact, control signal update packets and CAS signaling packets do not have the same payload size as the data packets. Therefore, the displayed bit rate is too large if control signal update packets or CAS signaling packets are included in the packet rate.
30 second egress rate 128034 bits/sec, 250 packets/sec	S, TE	This is the egress data rate of the most-recent 30 seconds, in bits/second and in packets/second, measured relative to the local oscillator. The packet rate is measured, but only the integer portion of the measurement is shown. The packets counted include the data packets as well as any control signal update packets or any CAS signaling packets. The bit rate is not measured independently. It is calculated from the measured packet rate. The calculation assumes that all packets have the same payload size as the data packets. In fact, control signal update packets and CAS signaling packets do not have the same payload size as the data packets. Therefore, the displayed bit rate is too large if control signal update packets or CAS signaling packets are included in the packet rate.
Tx interrupts: 12183	S, TE	This is the number of packets transmitted to the attached CPE. Normally, this should equal the Egress Packets above. If these two numbers are significantly different, this indicates some type of internal hardware or software failure.
Reorder queue flush: 0, visited: 0, max wait window: 0	S, TE	These counters pertain to the processing of packets that arrive out of sequence. Reorder queue flush is the number of missing packets. Reorder queue visited is the number of times that a packet was received out of sequence. Reorder queue max wait window is the maximum sequence number offset of any packet that was received out of sequence.
Network jitter max: 7 ms, average: 3 ms, min: 1 ms	S, TE	These measurements are not really jitter measurements. They are measurements of the inter-packet arrival times. Network jitter max is the integer portion of the maximum inter-packet arrival time. Network jitter average is the integer portion of the average inter-packet arrival time. Network jitter min is the integer portion of the minimum inter-packet arrival time.
Adaptive clock ppm correction is 9 tracking	S, TE	This line is displayed only if the CEM channel is configured for Adaptive Clock. It shows the integer portion of the current clock adjustment, in parts per million (ppm), relative to the local reference oscillator. The adaptive clock may be in either the tuning state or the tracking state.
Control Link state: Active	S	This line is displayed only if the control signal sampling rate on this CEM channel is configured to a non-zero value. It specifies whether the Active or the Fail interface control template (as described in Section 9.2.3.9) is currently being applied. The control link state may be in either the Active or Down state. The control link state is Down any time the CEM channel's de-jitter buffer is found to be empty at two consecutive samplings of the channel's ingress control signals. At such times, the CEM channel is down and the Fail interface control template is applied. At all other times, the control link state is Active and the active interface control template is applied.
Input control lead states: •rts = off •dtr = off •ll = off •rl = off	S	This line is displayed only if the control signal sampling rate on this CEM channel is configured to a non-zero value. It shows the current state of each of the INPUT control signals on this serial port.
Event history: 0x002B0000	S, TE	For Engineering debug purposes only.
Pkts dropped by burst limit: 0	S, TE	For Engineering debug purposes only.
Global stats for slot 1
Egr free buf: 256	S, TE	For Engineering debug purposes only.
Egr host overruns: 0	S, TE	For Engineering debug purposes only.
Egr unknown dest count: 0	S, TE	The Egr unknown dest count is the number of egress packets received with an unassigned destination UDP port.
Last unknown dest ip : 0.0.0.0, port: 0	S, TE	The last unknown dest ip is the destination IP address in the most-recently received packet with an unassigned destination UDP port. The last unknown dest port is the destination UDP port in the most-recently received packet with an unassigned destination UDP port.
Last unknown dest src ip : 0.0.0.0, port: 0	S, TE	The last unknown dest src ip is the source IP address in the most-recently received packet with an unassigned destination UDP port. The last unknown dest src port is the destination UDP port in the most-recently received packet with an unassigned destination UDP port.
Egr process switched: 0	S, TE	This is the number of egress packets that were process switched by the host router. For Engineering debug purposes only.
Egr oos: 0	S, TE	Not used.
Egr unknown src count: 0, last unknown src ip: 0.0.0.0, port: 0	S, TE	The Egr unknown src count is the number of egress packets received with a valid destination IP address and UDP port number but with an invalid source IP address or invalid source UDP port. The last unknown src ip is the source IP address in the most-recently received packet from an unknown source. The last unknown src port is the source UDP port in the most-recently received packet from an unknown source.
Ingr overruns: 0	S, TE	This is the number of packets dropped because the host router's CPU was too busy to process the packets.
NM cpu: 46.22 46.22 46.22 46.22	S,TE	This displays the percentage of the network module CPU's time that is consumed. Four consecutive eight-second intervals are shown. The most-recent eight second interval is shown first.

You can clear all of the CEM channel statistics and restart statistics collection using the clear cem command. The following examples shows counters being cleared with the clear cem command.

Router# clear cem 1/3/1 

Cleared counters for cem 1/3/1. 

Router# clear cem all 

Cleared counters for cem 1/1/0. Cleared counters for cem 1/3/1. Cleared counters for cem 
2/0/0. Cleared counters for cem 2/1/0. Cleared counters for cem 2/2/0. Cleared counters 
for cem 2/3/0. 

Additional References

For additional information related to the CEoIP feature, see the following references.

Related Documents

Related Topic	Document Title
CEoIP network modules	Release Notes for Cisco NM-CEM-4TE1 and NM-CEM-4SER Network Module Software

Standards

Standard	Title
GR-63	Network Equipment-Building System (NEBS) Requirements: Physical Protection
GR-1089	Electromagnetic Compatibility and Electrical Safety - Generic Criteria for Network Telecommunications Equipment
TIA/EIA-IS-968	Technical Requirements for Connection of Terminal Equipment to the Telephone Network

MIBs

MIB	MIBs Link
•CISCO-ENTITY-VENDORTYPE-OID-MIB •IF-MIB •OLD-CISCO-CHASSIS-MIB •RFC1406-MIB	To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL: http://www.cisco.com/go/mibs

RFCs

RFC	Title
RFC 1406	Definitions of Managed Objects for the DS1 and E1 Interface Types
RFC 2495	Definitions of Managed Objects for the DS1, E1, DS2 and E2 Interface Types Note CEoIP supports RFC 2495 to the same extent as Cisco IOS software supports this RFC.

Technical Assistance

Description	Link
The Cisco Technical Support website contains thousands of pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content.	http://www.cisco.com/techsupport

Command Reference

This section documents new commands (for Cisco IOS Release 12.3(7)T) and modified commands (for Cisco IOS Release 12.4(2)T).

•attach (CEM)

•cem

•cem-group

•clear cem

•clock mode

•clock rate

•clock source (CEM)

•control-lead sampling-rate

•control-lead state

•crc-threshold

•data-protection

•data-strobe

•dejitter-buffer

•failure

•idle-pattern

•ip dscp

•local ip address

•local udp port

•loopback (CEM)

•payload-compression

•payload-size

•remote udp port

•show cem

•signaling

•xconnect (CEM)

attach (CEM)

To enable port muxing to mux data from the slave port to the master port of a serial CEM channel, use the attach command in CEM configuration mode. To remove the slave port from the master port, use the no form of the command.

attach port

no attach port

Syntax Description

port	The port that will be attached to the master port for muxing the data.

Defaults

Port muxing is not active.

Command Modes

CEM

Command History

Release	Modification
12.4(2)T	This command was introduced.

Usage Guidelines

CEM serial ports can have a maximum of two master ports with any unique permutation of slave port. The attach command must follow the cem port command in a configuration. To remove the slave port from the master port use the no form of the command. If all the slave ports from the master port are removed, the master port will behave as a normal serial port (that is, no mux or demux operations will be preformed.).

Mux to Single Master Port

In this example, three slave ports are muxed to a single master port 0.

cem port 1/0/0

       attach 1

       attach 2

       attach 3

Mux to Multiple Master Ports

In this example, two master ports 0,1 have been created. Here, slave port 2 is muxed to master port 0 and slave port 3 is muxed to master port 1.

cem port 1/0/0

       attach 2

cem port 1/1/0

       attach 3

Related Commands

Command	Description
port	Specifies the CEM channel, or master port, to which slaves ports will be muxed.

cem

To enter circuit emulation (CEM) configuration mode, use the cem command in global configuration mode.

cem slot/port/channel

Syntax Description

slot	Slot number in which the Circuit Emulation over IP (CEoIP) network module (NM) is installed on the networking device.
/port	Port number on the CEoIP NM. The slash mark is required between the slot argument and the port argument.
/channel	Channel number that identifies the channel that you want to configure (T1/E1 only). The channel number on a serial port is always 0. The slash mark is required between the port argument and the channel argument.

Command Default

CEM configuration mode is not available.

Command Modes

Global configuration

Command History

Release	Modification
12.3(7)T	This command was introduced.

Usage Guidelines

Use this command to enter CEM configuration mode to allow the configuration of all CEM options.

Examples

The following example shows how to enter CEM configuration mode:

Router(config)# cem 1/2/0

Router(config-cem)#

Related Commands

Command	Description
clear cem	Clears CEM statistics.
show cem	Displays CEM statistics.

cem-group

To create a circuit emulation (CEM) channel from one or more time slots of a T1 or E1 line of an NM-CEM-4TE1 network module, use the cem-group command in controller configuration mode. To remove a CEM group and release the associated time slots, use the no form of this command.

cem-group group-number {unframed | timeslots time-slot-range [speed kbps]}

no cem-group group-number

Syntax Description

group-number	Channel number to be used for this group of time slots. •For T1 ports, the range is from 0 to 23. •For E1 ports, the range is from 0 to 30.
unframed	Specifies that a single CEM channel is being created including all time slots and the framing structure of the line.
timeslots	Specifies that a list of time slots is to be used as specified by the time-slot-range argument.
time-slot-range	List of the time slots to be included in the CEM channel. The list may include commas and hyphens with no spaces between the numbers.
speed	(Optional) Specifies the speed of the channels by specifying the number of kbps of each time slot to be used. This keyword applies only to T1 channels.
kbps	(Optional) Speed of the channel, in kbps. Must be one of the following: •56—Specifies a speed of 56 kbps where only the seven most significant bits (MSBs) of each eight-bit time slot are used. •64—Specifies a speed of 64 kbps where all eight bits of each eight-bit time slot are used.

Command Default

No CEM groups are defined.

Command Modes

Controller configuration

Command History

Release	Modification
12.3(7)T	This command was introduced.

Usage Guidelines

Use this command to create CEM channels on the T1 or E1 network module, NM-CEM-4TE1. A maximum of 64 channels may be created on an NM-CEM-4TE1.

Examples

The following example shows how to create circuit emulation group number 0 with a single CEM channel including all time slots and the framing structure of the line on an NM-CEM-4TE1.

Router(config-controller)# cem-group 0 unframed

The following example shows how to create circuit emulation channel number 6 with T1 channel time slots one through four, nine, and ten using all eight bits of each time slot on an NM-CEM-4TE1.

Router(config-controller)# cem-group 6 timeslots 1-4,9,10 speed 64

Related Commands

Command	Description
cem	Enters circuit emulation configuration mode.

clear cem

To clear circuit emulation (CEM) statistics, use the clear cem command in privileged EXEC mode.

clear cem {slot | slot/port/channel | all}

Syntax Description

slot	Clears the statistics for all CEM channels on the card in the specified slot (if the card is a Circuit Emulation over IP [CEoIP] card).
slot	Specifies the slot of the CEM channel to clear.
/port	Specifies the port of the CEM channel to clear. The slash mark is required between the slot argument and the port argument.
/channel	Specifies the CEM channel to clear. The slash mark is required between the port argument and the channel argument.
all	Clears the statistics for all CEM channels on the router.

Command Modes

Privileged EXEC

Command History

Release	Modification
12.3(7)T	This command was introduced.

Examples

The following example shows how to clear CEM statistics for CEM channel number 10 on the card installed in slot 1, port 1.

Router# clear cem 1/1/10

Related Commands

Command	Description
cem	Enters CEM configuration mode.
show cem	Displays CEM statistics.

clock mode

To configure the clock mode of a serial circuit emulation (CEM) channel, use the clock mode command in CEM configuration mode. To reset the clock mode to its default, use the no form of this command.

clock mode {normal | split}

no clock mode

Syntax Description

normal	Specifies normal mode, in which the DCE, whether it is a CEM over IP (CEoIP) data port or the external data device, provides both the receive clock and the transmit clock to the DTE.
split	Specifies split mode, in which the DCE, whether it is a CEoIP data port or the external device, provides the receiver clock to the DTE and the DTE provides the transmit clock to the DCE.

Command Default

The serial CEM channel clock defaults to normal mode.

Command Modes

CEM configuration

Command History

Release	Modification
12.3(7)T	This command was introduced.

Usage Guidelines

This command applies only to serial ports.

Examples

The following example shows how to configure the CEM clock for normal mode.

Router(config-cem)# clock mode normal

Related Commands

Command	Description
cem	Enters circuit emulation configuration mode.
clock rate	Configures the clock rate of a serial port.
clock source	Configures the clock source of a serial port.
show cem	Displays CEM statistics.

clock rate

To configure the clock rate for the hardware connections on serial interfaces, such as network interface modules (NIMs) and interface processors, to an acceptable bit rate, use the clock rate command in interface configuration mode or Circuit Emulation Module (CEM) configuration mode. To remove the clock rate if you change the interface from a DCE to a DTE device, use the no form of this command. Using the no form of this command on a DCE interface sets the clock rate to the hardware-specific default value.

clock rate {line | rate}

no clock rate

Syntax Description

line

Specifies that the clock source is the network. Note This keyword is not supported on CEM serial interfaces.

rate

Desired clock rate, in bits per second (bps): 1200, 2400, 4800, 9600, 19200, 38400, 56000, 64000, 72000, 125000, 148000, 250000, 500000, 800000, 1000000, 1300000, 2000000, 4000000, or 8000000. For some synchronous serial port adapters a nonstandard clock rate can be used. Refer to the hardware documentation for specific supported Lvalues. You can enter any value from 300 to 8000000 bps. The clock rate you enter is rounded (adjusted), if necessary, to the nearest value that your hardware can support except for the following standard rates: 1200, 2400, 4800, 9600, 14400, 19200, 28800, 38400, 56000, 64000, 128000, or 2015232.

Defaults

No clock rate is configured.

Command Modes

Interface configuration
CEM configuration in Circuit Emulation Module (CEM)

Command History

Release	Modification
10.0	This command was introduced.
11.3	This command was modified to include nonstandard clock rates for the PA-8T-V35, PA-8T-X21, PA-8T-232, and PA-4T+ synchronous serial port adapters.
12.3(2)T	This command was modified to include the line keyword.
12.4(5)M	The value range for the rate argument was updated to support additional baud rates of 300, 600, 1792K, and 1920K bps on CEM Network Modules.

Usage Guidelines

Using the no form of this command on a DCE interface sets the clock rate to the hardware-dependent default value.

Cable Length

Be aware that the fastest speeds might not work if your cable is too long and that speeds faster than 148,000 bits per second are too fast for EIA/TIA-232 signaling. It is recommended that you use the synchronous serial EIA/TIA-232 signal at speeds up to 64,000 bits per second only. To permit a faster speed, use EIA/TIA-449 or V.35.

Synchronous Serial Port Adapters

For the synchronous serial port adapters (PA-8T-V35, PA-8T-X21, PA-8T-232, and PA-4T+) on Cisco 7200 series routers and on second-generation Versatile Interface Processors (VIP2s) in Cisco 7500 series routers, the clock rate that you enter is rounded (if needed) to the nearest value that your hardware can support. To display the clock rate value for the port adapter, use the show running-config command.

If you plan to boot from a network (TFTP) server over a synchronous serial port adapter interface and have a boot image prior to Cisco IOS Release 11.1(9)CA that does not support nonstandard (rounded) clock rates for the port adapters, you must use one of the following standard clock rates:

1200, 2400, 4800, 9600, 19200, 38400, 56000, 64000

CEM Network Modules

The following clock rates are supported on CEM Network Modules:

200, 300, 400, 600, 800, 1200, 1800, 2400, 3200, 3600, 4800, 6400, 7200, 8000, 9600, 12000, 12800, 14400, 16000, 16800, 19200, 24000, 28800, 32000, 38400, 48000, 56000, 57600, 64000, 76800, 84000, 96000, 112000, 115200, 128000, 144000, 168000, 192000, 224000, 230400, 256000, 288000, 336000, 384000, 448000, 512000, 672000, 768000, 772000, 896000, 1024000, 1152000, 1344000, 1536000, 1544000, 1792000, 1920000, 2048000

Examples

Network as Clock Source Example

The following example shows how to set the clock rate to use the network as the clock source:

Router(config)# interface serial 0

Router(config-if)# clock rate line

Clock Rate on Synchronous Serial Port Example

The following example shows how to set the clock rate on a synchronous serial port adapter in slot 5, port 0 to 1,234,567 bps. In this example, the clock rate is adjusted to 1,151,526 bps.

Router(config)# interface serial 5/0

Router(config-if)# clock rate 1234567

%Clockrate rounded to nearest value that your hardware can support.

Clock Rate Rounded on Serial Enterface Example

The following example shows how to determine the exact clock rate that the serial interface was rounded to by using the show running-config command.

Router# show running-config

Building configuration...

.

.

.

!

interface Serial5/0

 no ip address

 clockrate 1151526

!

CEM Channel Example

This example shows the statistics for the current CEM configuration.

Router# show cem 4/1/0

cem info

cem 4/1/0 is up

Line state is up

Operational state is active

Near end ip address: 172.31.28.2, udp port: 15901

Far end ip address: 172.31.28.10, udp port: 15901

IP payload size: 512

IP dscp : 0x28

Idle pattern length: 8 , Idle Pattern: 0xFF

Payload compression is disabled

Data protection is disabled

Dejitter buffer size is 60 ms

Channel clock rate is 2048000 bps

Physical interface is E1 unframed

Ingress packets: 32505156, dropped: 0, overruns: 0

Egress packets: 32505158, dropped: 637, lost pkts: 0

Egress out of sequence pkts: 0

Egress overruns: 16, underruns: 244

Egress corrupt pkts rcvd: 0

30 second ingress rate 2050321 bits/sec, 500 packets/sec

30 second egress rate 2050184 bits/sec, 500 packets/sec

Tx interrupts: 32504249

Reorder queue flush: 0, visited: 0, max wait window: 0

Network jitter max: 8 ms, average: 1 ms, min: 0 ms

Adaptive clock ppm correction is 2 tracking

Event history: 0x00230058

Pkts dropped by burst limit: 0

Global stats for slot 4

************************

Egr free buf: 255

Egr host overruns: 0

Egr unknown dest count: 0

Last unknown dest ip : 0.0.0.0, port: 0

Last unknown dest src ip : 0.0.0.0, port: 0

Egr process switched: 0

Egr oos: 0

Egr unknown src count: 0, last unknown src ip: 0.0.0.0, port: 0

Ingr overruns: 0

NM cpu: 53.56 53.51 53.45 53.54

Related Commands

Command	Description
show running-config	Displays the current configuration.
show cem	Displays circuit emulation statistics.

clock source (CEM)

To configure the clock source of a circuit emulation (CEM) network module port, use the clock source command in CEM configuration mode or controller configuration mode. To return to the default clock source, use the no form of this command.

Cisco NM-CEM-4SER

clock source {internal | loop | adaptive}

no clock source {internal | loop | adaptive}

Cisco NM-CEM-4TE1

clock source {internal | line | adaptive channel-number [closed-loop | open-loop | coarse]}

no clock source {internal | line | adaptive channel-number [closed-loop | open-loop | coarse]}

Syntax Description

internal	Specifies that the clocks provided by the port to the attached CPE are derived from the router's TDM bus backplane clock (if one exists in the router) or from the onboard oscillator on the network module. This is the default clock source for a Cisco NM-CEM-4SER.
loop	(Cisco NM-CEM-4SER network module only) Specifies that the clock provided by the port to the attached CPE is derived from the clock received on the same port from the attached CPE.
line	(Cisco NM-CEM-4TE1 network module only) Specifies that the port transmit clock is derived from receive clock on the same port. This is the default clock source for a Cisco NM-CEM-4TE1.
adaptive	Specifies that the clocks provided by the port to the attached CPE are locally synthesized on the basis of the average data content of the local dejitter buffer.
channel-number	(Cisco NM-CEM-4TE1 network module only) Number of the channel whose dejitter buffer is to be used to synthesize the transmit clock of the port.
closed-loop	(Optional; Cisco NM-CEM-4TE1 network module only) Specifies that the adaptive clock algorithm enhancements are used to improve the adaptive clock accuracy. The same clock must be used in both directions for the closed loop mode. This keyword is supported in Cisco IOS Release 12.4(2)T and later releases.
open-loop	(Optional; Cisco NM-CEM-4TE1 network module only) Specifies that some of the adaptive clock algorithm enhancements are used but the clocks do not have to be the same in both directions. This is the default. This keyword is supported in Cisco IOS Release 12.4(2)T and later releases.
coarse	(Optional; Cisco NM-CEM-4TE1 network module only) Specifies that the original adaptive clock algorithm without the enhancements is used. This keyword is supported in Cisco IOS Release 12.4(2)T and later releases.

Command Default

Cisco NM-CEM-4SER

The clock source defaults to internal.

Cisco NM-CEM-4TE1

The clock source defaults to line.

Command Modes

Cisco NM-CEM-4SER

CEM configuration

Cisco NM-CEM-4TE1

Controller configuration

Command History

Release	Modification
12.3(7)T	This command was introduced.
12.4(2)T	The closed-loop, open-loop, and coarse keywords were added.

Usage Guidelines

When clock source internal is specified, the clocks provided by the network module are derived from either of the following source:

•The router's backplane TDM clock frequency (in any router equipped with a TDM backplane bus)

•The master oscillator on the network module (in any router not equipped with a TDM backplane bus)

When the adaptive keyword is specified, the clocks provided by the network module are derived from the same source as in the clock source internal case. However, the derived frequency is further adjusted up or down on the basis of the measured average fill of the egress dejitter buffer of the connection. If the dejitter buffer is perceived to be slowly filling, the frequency is adjusted slightly upward. If the dejitter buffer is perceived to be slowly depleting, the frequency is adjusted slightly downward.

Cisco NM-CEM-4SER

When the loop keyword is specified, the clock provided by the NM-CEM-4SER is the same as the clock provided to the NM-CEM-4SER from the attached CPE. The specification of clock source loop is only valid when the clock mode split command is specified. The clock mode command is used only during configuration of the NM-CEM-4SER.

Cisco NM-CEM-4TE1

In Cisco IOS Release 12.4(2)T, the adaptive clocking algorithm is enhanced to provide better adaptive clock accuracy. Three new keywords are used to specify the preferred mode:

•closed-loop—Specifies the closed loop mode. Taking advantage of the fact that a T1 or E1 link uses the same clock in both directions, the adaptive clock algorithm enhancements are used to improve the adaptive clock accuracy. The same clock must be used in both directions for the closed loop mode, and both ends of the CEM must be running a Cisco IOS release that supports the enhanced adaptive clock algorithm. Use the closed loop mode when clock accuracy is required, the master clock from the customer premises equipment (CPE) is of good quality, and the clocks are the same in both directions of the T1 or E1 link.

---

Note Do not use the closed loop mode in applications where the clocks are different for the two directions of the T1 or E1 link.

---

•open-loop—Specifies the open loop mode. Some of the adaptive clock algorithm is used, but this mode does not require the clocks to be the same in both directions. This mode is compatible with previous Cisco IOS releases and is the default mode if no keyword is specified. Use the open loop mode when the master clock from the CPE is of good quality, but the clocks are not the same in both directions of the T1 or E1 link.

•coarse—Specifies the coarse mode. The coarse mode uses the original adaptive clock algorithm and is used when the stability of the master clock derived from the CPE is not guaranteed. This mode is compatible with previous Cisco IOS releases.

Examples

The following example shows how to configure the clock source for the serial CEM network module, NM-CEM-4SER:

Router(config-cem)# clock source loop

The following example shows how to configure the clock source for the T1/E1 CEM network module, NM-CEM-4TE1:

Router(config-controller)# clock source adaptive 6

The following example shows how to configure the clock source for an NM-CEM-4TE1 using the closed-loop mode to improve the adaptive clock accuracy:

Router(config-controller)# clock source adaptive 5 closed-loop

Related Commands

Command	Description
cem	Enters circuit emulation configuration mode.
clock mode	Configures the clock mode on an NM-CEM-4SER network module.
show cem	Displays CEM channel statistics.

control-lead sampling-rate

To configure the sampling rate of input control leads, use the control-lead sampling-rate command in CEM configuration mode.

control-lead sampling-rate rate

Syntax Description

rate	Integer that specifies the number of samples per second. Range is from 0 to 20. Default is 0.

Command Default

The input control lead sampling rate defaults to 0 (no sampling).

Command Modes

CEM configuration

Command History

Release	Modification
12.3(7)T	This command was introduced.

Usage Guidelines

This command applies only to serial channels. This command does not have a no form; to disable control-lead sampling, set the rate argument to 0.

Examples

The following example shows how to configure the ingress control-lead sampling rate to 20 samples per second on a serial CEM port.

Router(config-cem)# control-lead sampling-rate 20

Related Commands

Command	Description
cem	Enters circuit emulation configuration mode.
clear cem	Clears CEM channel statistics.
control-lead state	Specifies the state of an output control lead.
show cem	Displays CEM channel statistics.

control-lead state

To specify the state of an output control lead, use the control-lead state command in CEM configuration mode. The choice of output lead depends on whether the port is DCE or DTE.

control-lead state {active | fail} output-lead {on | off | follow} [{local | remote} follow-lead] [and|or]

Syntax Description

active	Active template configuration.
fail	Failed template configuration.
output-lead	Specifies the name of the output control lead. The choice of the control lead depends on whether the port is DCE or DTE.
on	Activates the lead.
off	Deactivates the lead.
follow	Specifies the control lead state to follow.
local	(Optional) Specifies a local lead state.
remote	(Optional) Specifies a remote lead state.
follow-lead	(Optional) Specifies the local or remote input control lead for this control lead to follow. The choice of the control lead depends on whether the port is DCE or DTE.
and	Performs a Boolean AND operaton with specified remote follow-lead argument.
or	Performs a Boolean OR operaton with specified remote follow-lead argument.

Command Default

The default Active template that is activated depends on whether the port is DCE or DTE. The default Fail template deactivates all signals. Table 2 shows the various control-lead default states.

Table 2 Control-Lead Default States

Lead Number	DCE Name	DTE Name	Active Default	Fail Default
1	CTS	RTS	On	Off
2	DSR	DTR	On	Off
3	DCD	—	On	Off
4	—	LL	Off	—
5	TM	—	On	Off
6	RI	RL	Off	Off

Command Modes

CEM configuration

Command History

Release	Modification
12.3(7)T	This command was introduced.
12.4(2)T	The and and or keywords were added to support port muxing.

Usage Guidelines

This command applies only to serial ports. This command does not have a no form; to disable the control lead, specify the off keyword.

Output Control Lead States

The state of each output control lead may be specified to assume a constant level (on or off) or to change on the basis of the state of any input control lead, either at the local data port or at the remote data port.

EIA Pin Maps

Local EIA pin of the muxed ports map to a single EIA pin on the remote side, such that a state change in any of the muxed EIA pins are reflected on the mapped EIA pin on the remote side

Examples

The following example shows how to specify the state of an output control lead.

Router(config-cem)# control-lead state active cts on

Related Commands

Command	Description
cem	Enters circuit emulation configuration mode.
control-lead sampling-rate	Configures the sampling rate of input control leads.
show cem	Displays CEM channel statistics.

crc-threshold

To define a severely errored second (SES) by specifying the number of cyclic redundancy check (CRC) errors that occur in one second, use the crc-threshold command in controller configuration mode. To return to the default value, use the no form of this command.

crc-threshold value

no crc-threshold

Syntax Description

value

Number of CRC errors in one second that results in the second being declared a severely errored second (SES). Range is from 0 to 3000. Default is 320.

Command Default

A default SES is defined by a value of 320 CRC errors per second.

Command Modes

Controller configuration

Command History

Release	Modification
12.3(7)T	This command was introduced.

Usage Guidelines

On a T1 port, this command applies only if extended super frame (ESF) framing is used because the super frame (SF) (also known as D4) frame structure does not include any CRC protection.

This command does not apply to an E1 port.

Examples

The following example shows how to set the CRC threshold at 512 CRC errors in one second.

Router(config-controller)# crc-threshold 512

data-protection

To enable data protection for a circuit emulation (CEM) channel, use the data-protection command in CEM configuration mode. To disable data protection, use the no form of this command.

data-protection

no data-protection

Syntax Description

This command has no arguments or keywords.

Command Default

Data protection is disabled for a CEM channel.

Command Modes

CEM configuration

Command History

Release	Modification
12.3(7)T	This command was introduced.

Examples

The following example demonstrates how to enable data protection.

Router(config-cem)# data-protection

Related Commands

Command	Description
cem	Enters circuit emulation configuration mode.
clear cem	Clears CEM channel statistics.
show cem	Displays CEM channel statistics.

data-strobe

To specify an input control lead to be monitored as an indicator of valid data, use the data-strobe command in CEM configuration mode. To disable the monitoring of an input control lead, use the no form of this command.

data-strobe input-lead {on | off}

no data-strobe

Syntax Description

input-lead	Specifies the input lead. The choice of leads depends on whether the port is DCE or DTE.
on	Enables packet creation when the lead is asserted.
off	Enables packet creation when the lead is deactivated.

Command Default

No input control lead is monitored.

Command Modes

CEM configuration

Command History

Release	Modification
12.3(7)T	This command was introduced.

Usage Guidelines

Any input control signal on a serial data port may be configured as a "data strobe" to indicate to the NM-CEM-4SER network module whether ingress data on the port should be encapsulated for transmission or ignored. If the data-strobe command is specified with the on keyword, data packets are created and sent when the input lead is asserted. If the data strobe is off (either intentionally or as a result of the failure of the customer premises equipment [CPE]), no data packets are created, and this results in preservation of bandwidth in the IP network.

This command applies only to serial ports.

Examples

The following example demonstrates how to specify that packets are to be created and sent to the far end only when the DTR input control lead is asserted.

Router(config-cem)# data-strobe dtr on

Related Commands

Command	Description
cem	Enters circuit emulation configuration mode.
clear cem	Clears CEM channel statistics.
control-lead sampling rate	Configures the sampling rate of input control leads.
control-lead state	Specifies the state of an output control lead.
show cem	Displays CEM channel statistics.

dejitter-buffer

To configure the size of the dejitter buffer, use the dejitter-buffer command in CEM configuration mode. To restore the dejitter buffer to its default size, use the no form of this command.

dejitter-buffer size

no dejitter-buffer

Syntax Description

size	Size, in milliseconds, of the dejitter buffer. The range is from 5 to 500. The default is 60.

Command Default

The dejitter buffer defaults to 60 milliseconds.

Command Modes

CEM configuration

Command History

Release	Modification
12.3(7)T	This command was introduced.

Examples

The following example shows how to set the dejitter buffer to 200 milliseconds.

Router(config-cem)# dejitter-buffer 200

Related Commands

Command	Description
cem	Enters circuit emulation configuration mode.
clear cem	Clears CEM channel statistics.
show cem	Displays CEM channel statistics.

failure

To specify a time period before a circuit emulation (CEM) connection enters, or recovers from, a failed state, use the failure command in CEM configuration mode. To remove the time period, use the no form of this command.

failure {activation | deactivation} msec

no failure {activation | deactivation}

Syntax Description

activation	Specifies how long the software will wait for the detection of a failure of a CEM connection until the CEM channel enters the failed state.
deactivation	Specifies how long the software will wait from the detection of a repair to the CEM connection until the CEM channel is returned to an active (up) state.
msec	Time, in milliseconds, in the range from 50 to 60000. Default is 2000. Any value entered is rounded up to the next multiple of 50 milliseconds.

Command Default

CEM channels enter or recover from a failed state immediately.

Command Modes

CEM configuration

Command History

Release	Modification
12.3(7)T1	This command was introduced.

Usage Guidelines

The detection of the failure of a CEM connection is determined by an underflow of the egress dejitter buffer. The failed state for a serial channel (on an NM-CEM-4SER) is defined by the control-lead state command, where the failed state for each egress control lead is specified. The failed state for a T1/E1 channel (on an NM-CEM-4TE1) is defined by the signaling command.

The detection of the repair of a CEM connection is determined by the egress dejitter buffer returning to its intended half-full state. The active state for a serial channel (on an NM-CEM-4SER) is defined by the control-lead state command where the active state for each egress control lead is specified. The active state for a T1/E1 channel (on an NM-CEM-4TE1) is defined using the signaling command that can be configured to carry the ABCD signaling bits transparently from end to end.

Examples

The following example shows that after a CEM connection (on an NM-CEM-4SER) failure is detected, the software will wait for 200 milliseconds before the CEM channel enters the failed state:

Router(config)# cem 2/0/0

Router(config-cem)# control-lead state fail cts on

Router(config-cem)# failure activation 200

The following example shows that after a CEM connection repair (on an NM_CEM-4TE1) is detected, the software will wait for 5000 milliseconds before the CEM channel enters the active (up) state:

Router(config)# cem 1/0/0

Router(config-cem)# signaling state active cts on

Router(config-cem)# failure deactivation 5000

Related Commands

Command	Description
cem	Enters circuit emulation configuration mode.
control-lead state	Specifies the state of an output control lead.
show cem	Displays CEM statistics.
signaling	Enables channel-associated signaling (CAS).

framing (CEM)

To specify the framing format of a circuit emulation (CEM) T1 or E1 port, use the framing command in controller configuration mode. To reset the framing format of the port to its default value, use the no form of this command.

T1 Port

framing {sf | esf | unframed}

no framing

E1 Port

framing {crc4 | no-crc4 | unframed}

no framing

Syntax Description

sf	Specifies that the T1 port framing format is set to super frame (SF) format, also commonly known as D4 framing format.
esf	Specifies that the T1 port framing format is set to extended super frame (ESF) format. This is the default for a T1 line.
crc4	Specifies that the E1 port framing format is set to the G.704 standard with the optional CRC4 mechanism defined in time slot 0 enabled. This is the default for a E1 line.
no-crc4	Specifies that the E1 port framing format is set to the G.704 standard with the optional CRC4 mechanism defined in time slot 0 disabled.
unframed	Specifies that no framing structure is sought (on the ingress data stream) or imposed (on the egress data stream) on the T1 or E1 port.

Command Default

The framing format of a T1 line defaults to esf.
The framing format of an E1 line defaults to crc4.
If an unframed CEM channel is created on the port using the cem-group command, no framing structure is sought or imposed.

Command Modes

Controller configuration

Command History

Release	Modification
12.3(7)T	This command was introduced to support circuit emulation.

Usage Guidelines

Framing must be configured to match the framing format used by the attached equipment.

In order to change a line between unframed and any framed mode, you must first delete the CEM channels defined in the line.

Examples

The following example shows how to set the framing format of a CEM T1 port to be super frame format.

Router(config-controller)# framing sf

The following example shows how to set the framing format of a CEM E1 port to the G.704 standard with the optional CRC4 mechanism defined in time slot 0 disabled.

Router(config-controller)# framing no-crc4

Related Commands

Command	Description
cem-group	Creates CEM channels on T1 or E1 ports.

idle-pattern

To define the idle pattern that a circuit emulation (CEM) channel transmits when the channel experiences an underrun condition or to replace any missing packets, use the idle-pattern command in CEM configuration mode. To stop sending idle pattern data, use the no form of this command.

idle-pattern {pattern | length pattern1 [pattern2]}

no idle-pattern

Syntax Description

pattern	An 8-bit hexadecimal number. T1 and E1 channels require only this argument.
length	Length, in bits, of the pattern. Serial cards require that you enter a value for length.
pattern1	Specifies (in hex notation) up to 32 bits of the least significant bits of the idle data pattern. Default is 0xFF.
pattern2	(Optional) Specifies (in hex notation) the most significant bits of the idle data pattern. If the length argument is 32 bits or less, this argument is not permitted.

Command Default

For T1 or E1 channels, the default idle pattern is 0xFF.
For serial channels, the default idle pattern is 0xFF and 8 bits in length.

Command Modes

CEM configuration

Command History

Release	Modification
12.3(7)T	This command was introduced.

Usage Guidelines

Idle pattern data is always sent in multiples of one entire packet payload. If a single packet is missing from the arriving data stream it is replaced by an idle packet of the same payload size and composed of repetitions of the specified idle pattern. If the CEM channel outbound (egress) buffer experiences an underrun condition, identical idle packets are transmitted until the dejitter buffer is filled to at least half its total depth.

Examples

The following example shows how to configure a 32-bit idle pattern for a serial CEM channel.

Router(config-cem)# idle-pattern 32 0x12345678

Related Commands

Command	Description
cem	Enters circuit emulation configuration mode.
clear cem	Clears CEM channel statistics.
show cem	Displays CEM channel statistics.

ip dscp

To enable the use of IP differentiated services code point (DSCP) for packets that originate from a circuit emulation (CEM) channel, use the ip dscp command in CEM configuration mode. To disable the use of IP DSCP, use the no form of this command.

ip dscp [dscp-value]

no ip dscp

Syntax Description

dscp-value

(Optional) Value placed in the DSCP field of IP packets that originate from a CEM channel. Range is from 0 to 63. Default is 46.

Command Default

IP DSCP is enabled for packets that originate from a CEM channel.

Command Modes

CEM configuration

Command History

Release	Modification
12.3(7)T	This command was introduced.

Usage Guidelines

DSCP is mutually exclusive from both IP type of service (ToS) and IP precedence. Thus, if DSCP is configured, the ip tos command and the ip precedence command are both unavailable at the command-line interface (CLI).

Examples

The following example shows how to set the IP DSCP field value to 36.

Router(config-cem)# ip dscp 36

Related Commands

Command	Description
ip precedence	Configures the IP precedence bits for the CEM channel.
ip tos	Configures the IP ToS bits for the CEM channel.

local ip address

To define an IP address to identify a local circuit emulation (CEM) channel, use the local ip address command in CEM xconnect configuration mode.

local ip address ip-address

Syntax Description

ip-address

IP address of a regular or loopback interface in the local router. Default is 0.0.0.0

Command Default

The default local IP address is 0.0.0.0 for a CEM channel.

Command Modes

CEM xconnect configuration

Command History

Release	Modification
12.3(7)T	This command was introduced.

Usage Guidelines

This command does not have a no form. To remove a local IP address, either configure a new local IP address or enter the no xconnect command to disable the connection and all its parameters.

The local IP address used to identify the local end of a CEM connection must be the same as the IP address defined by the remote-ip-address argument used in the xconnect command to identify the CEM channel at the other end of the CEM connection.

---

Note If there are multiple CEM connections that originate from the same router, they may share the same
local IP address provided that each local IP address defines a unique UDP port number using the
local udp port command.

---

Examples

The following example demonstrates how to configure the IP address of the local endpoint of the CEM over IP (CEoIP) connection.

Router(config-cem-xconnect)# local ip address 10.0.5.1

Related Commands

Command	Description
clear cem	Clears CEM statistics.
local udp port	Defines the UDP port at the local end of a CEM connection.
show cem	Displays CEM statistics.
xconnect (CEM)	Builds one end of a CEM connection and enters CEM xconnect configuration mode.

local udp port

To define the User Datagram Protocol (UDP) port of the local endpoint of a circuit emulation (CEM) connection, use the local udp port command in CEM xconnect configuration mode.

local udp port port

Syntax Description

port	Number of the CEM local UDP port. Possible values are 0, 2141, and 15872 through 16383. The default is 0.

Command Default

The default local UDP port number is 0 for the local endpoint of a CEM connection.

Command Modes

CEM xconnect configuration

Command History

Release	Modification
12.3(7)T	This command was introduced.

Usage Guidelines

This command does not have a no form. To remove a local UPD port number, either configure a new UPD port number or enter the no xconnect command to disable the connection and all its parameters.

Examples

The following example demonstrates how to configure the UDP port of the local endpoint of the CEM over IP (CEoIP) connection.

Router(config-cem-xconnect)# local udp port 2141

Related Commands

Command	Description
remote udp port	Defines the UDP port of the remote endpoint of a CEM connection.
show cem	Displays CEM channel statistics.
xconnect (CEM)	Builds one end of a CEM connection and enters CEM xconnect configuration mode.

loopback (CEM)

To set the loopback method for testing a T1, E1, or serial CEM interface, use the loopback command in controller configuration or CEM configuration mode. To remove any existing loopback, use the no form of this command.

Cisco NM-CEM-4SER

loopback {local | network}

no loopback

Cisco NM-CEM-4TE1

loopback {local {payload | line} | network}

no loopback

Syntax Description

local

Places the interface into local loopback mode and creates a loopback wherein information received from the locally-attached customer premises equipment (CPE) is transmitted back to the locally-attached CPE. •payload—(Used only if a local loopback is specified for a T1/E1 channel) Creates a loopback of only the data in individual time slots. In this mode, framing bits are terminated and then regenerated instead of being looped back. This mode is not available if the port is configured for framing unframed. •line—(Used only if a local loopback is specified for a T1/E1 channel) Creates a full physical layer loopback of all bits, including data and framing bits.

network

Creates a loopback wherein data received over the network from the remote CPE is transmitted back to the remote CPE.

Command Default

No loopback is configured for a CEM interface.

Command Modes

Cisco NM-CEM-4SER

CEM configuration

Cisco NM-CEM-4TE1

Controller configuration

Command History

Release	Modification
12.3(7)T	This command was introduced.

Usage Guidelines

Use this command to create a loopback for a CEM interface. You can use a loopback to test for equipment malfunction caused by the interface.

The NM-CEM-4TE1 does not respond to loopback requests initiated by the CPE, locally attached or remote, using the extended super frame (ESF) Facility Data Link (FDL) mechanism or by any other mechanism.

The NM-CEM-4SER does not respond to any form of loopback request initiated by the locally attached or remote CPE on the Local Loop (LL) or Remote Loop (RL) control leads. Nor does the NM-CEM-4SER respond to any form of loopback request initiated by the locally attached or remote CPE using in-band loopback codes.

Examples

The following example shows how to create a loopback on a CEM T1/E1 interface so that data received from a remote CPE is transmitted back to the remote CPE on the network.

Router(config-controller)# loopback network

The following example shows how to create a loopback of data in individual time slots on a CEM T1/E1 interface. Data received from a locally attached CPE will be sent back to the locally attached CPE.

Router(config-controller)# loopback local payload

The following example shows how to create a loopback on a serial CEM channel so that data received from a remote CPE is transmitted back to the remote CPE on the network.

Router(config-cem)# loopback network

Related Commands

Command	Description
cem	Enters circuit emulation configuration mode.
controller	Enters controller configuration mode.

payload-compression

To enable payload compression, use the payload-compression command in CEM configuration mode. To disable payload compression, use the no form of this command.

payload-compression

no payload-compression

Syntax Description

This command has no arguments or keywords.

Command Default

Payload compression is disabled by default.

Command Modes

CEM configuration

Command History

Release	Modification
12.3(7)T	This command was introduced.

Usage Guidelines

Payload compression can be enabled only for a maximum of 3 Mbps per network module.

Examples

The following example demonstrates how to enable payload compression.

Router(config-cem)# payload-compression

Related Commands

Command	Description
cem	Enters circuit emulation configuration mode.
payload-size	Configures payload size.
show cem	Displays CEM statistics.

payload-size

To configure the payload size of a circuit emulation (CEM) over IP (CEoIP) packet, use the payload-size command in CEM configuration mode. To restore the default payload size, use the no form of this command.

payload-size size

no payload-size

Syntax Description

size

Integer that defines the number of bytes per CEoIP packet. Range is from 1 to 1312. The maximum configurable payload size is as follows: •1312 bytes if data protection is not enabled •656 bytes if data protection is enabled The minimum configurable payload size for an unframed T1 or E1 channel is 256 bytes. The minimum configurable payload size for a framed T1 or E1 channel is as follows: •56 bytes if the data rate is less than or equal to 256,000 kbps •128 bytes if the data rate is greater than 256,000 kbps and less than or equal to 512,000 kbps •256 bytes if the data rate is greater than 512,000 kbps The minimum configurable payload size for a serial channel is as follows: •1 byte if the data rate is less than or equal to 2400 kbps •4 bytes if the data rate is greater than 2400 kbps but less than or equal to 9600 kbps •16 bytes if the data rate is greater than 9600 kbps but less than or equal to 32,000 kbps •32 bytes if the data rate is greater than 32,000 kbps but less than or equal to 64,000 kbps •64 bytes if the data rate is greater than 64,000 kbps but less than or equal to 256,000 kbps •128 bytes if the data rate is greater than 256,000 kbps but less than or equal to 512,000 kbps •256 bytes if the data rate is greater than 512,000 kbps Note For T1 and E1, the integer must be a multiple of the number of time slots and 16.

Command Default

The default payload size for a serial channel is 32 bytes. Defaults for T1 and E1 channels are shown in Table 3 and Table 4.

Table 3 Default Payload Size for N*64-kbps T1/E1 Channels

Number of Time Slots	Channel Data Rate (kbps)	Default Payload Size (bytes)
1	64	64
2	128	64
3	192	96
4	256	64
5	320	160
6	384	144
7	448	224
8	512	128
9	576	288
10	640	320
11	704	352
12	768	288
13	832	416
14	896	336
15	960	480
16	1024	256
Unframed T1	1544	512
Unframed E1	2048	512
17	1088	544
18	1152	576
19	1216	608
20	1280	560
21	1344	672
22	1408	528
23	1472	736
24	1536	528
25	1600	800
26	1664	624
27	1728	864
28	1792	560
29	1856	928
30	1920	720
31	1984	992

Table 4 Default Payload Size for N*56-kbps T1 Channels

Number of Time Slots	Channel Data Rate (kbps)	Default Payload Size (bytes)
1	56	56
2	112	56
3	168	168
4	224	56
5	280	280
6	336	168
7	392	168
8	448	168
9	504	504
10	560	280
11	616	616
12	672	336
13	728	728
14	784	280
15	840	840
16	896	336
17	952	952
18	1008	1008
19	1064	1064
20	1120	560
21	1176	672
22	1232	616
23	1288	1288
24	1344	672

Command Modes

CEM configuration

Command History

Release	Modification
12.3(7)T	This command was introduced.

Usage Guidelines

Use this command to configure the size of each CEoIP packet. Smaller sizes reduce delay but diminish efficiency.

---

Note The payload size must be a multiple of the number of time slots and 16. The payload size entered
by the user will be automatically changed to match the above requirement, and a console message
will inform the user of this change.

---

Examples

The following example demonstrates how to configure a payload size of 224.

Router(config-cem)# payload-size 224

Related Commands

Command	Description
cem	Enters circuit emulation configuration mode.
payload-compression	Enables payload compression.
show cem	Displays CEM channel statistics.

remote udp port

To define the User Datagram Protocol (UDP) port of the remote endpoint of a circuit emulation (CEM) connection, use the remote udp port command in CEM xconnect configuration mode.

remote udp port port

Syntax Description

port	Number of the circuit emulation (CEM) remote UDP port. Possible values are 0, 2142, and 15872 through 16383. The default is 0.

Command Default

The default UDP port number is 0 for the remote endpoint of a CEM connection.

Command Modes

CEM xconnect configuration

Command History

Release	Modification
12.3(7)T	This command was introduced.

Usage Guidelines

This command does not have a no form. To remove a remote UPD port number, either configure a new UPD port number or enter the no xconnect command to disable the connection and all its parameters.

Examples

The following example demonstrates how to configure the UDP port of the remote endpoint of the CEM over IP (CEoIP) connection.

Router(config-cem-xconn)# remote udp port 2142

Related Commands

Command	Description
cem	Enters circuit emulation configuration mode.
local udp port	Defines the UDP port of the local endpoint of a CEM connection.
show cem	Displays CEM channel statistics.
xconnect (CEM)	Builds one end of a CEM connection and enters CEM xconnect configuration mode.

show cem

To display circuit emulation (CEM) statistics, use the show cem command in privileged EXEC mode.

show cem {slot/port/channel | summary}

Syntax Description

slot	Slot number where the Circuit Emulation over IP (CEoIP) network module (NM) is installed on the networking device.
/port	Port number on the CEoIP NM. The slash mark is required between the slot argument and the port argument.
/channel	Channel number that identifies the channel that you want to configure (T1/E1 only). The channel number on a serial port is always 0. The slash mark is required between the port argument and the channel argument.
summary	Displays summary CEM statistics.

Command Modes

Privileged EXEC

Command History

Release	Modification
12.3(7)T	This command was introduced.
12.4(2)T	Output was modified to support enhanced adaptive clocking.

Examples

show cem summary Example

The following example shows a summary of some of the configuration parameters of the CEM channels.

Router# show cem summary

cem summary

CSTATE: CEM state

LSTATE: line state

OSTATE: operational state

PSIZE: payload-size

PCOMP: payload-compression

DPROT: data-protection

CEM    CSTATE    LSTATE     OSTATE          PSIZE    PCOMP      DPROT

----------------------------------------------------------------------

2/0/0   shutdown   up     config-incomplete   256    disabled   disabled 

2/1/0   shutdown   up     config-incomplete   256    disabled   disabled 

2/2/0   shutdown   up     config-incomplete   256    disabled   disabled 

2/3/0   shutdown   up     config-incomplete   256    disabled   disabled 

4/0/1   up         up     active              96     enabled    disabled 

4/0/2   up         up     active              96     enabled    disabled 

4/0/3   up         up     active              96     enabled    disabled 

4/0/4   up         up     active              96     enabled    disabled 

4/0/5   up         up     active              96     enabled    disabled 

4/0/6   up         up     active              96     enabled    disabled 

4/0/7   up         up     active              96     disabled   disabled 

4/0/8   up         up     active              96     disabled   disabled 

4/0/9   up         up     active              96     disabled   disabled 

4/0/10  up         up     active              96     disabled   disabled 

4/0/11  up         up     active              96     disabled   disabled 

4/0/12  up         up     active              96     disabled   disabled 

4/0/13  up         up     active              96     disabled   disabled 

4/0/14  up         up     active              96     disabled   disabled 

4/1/1   down       down   config-incomplete   96     enabled    disabled 

4/1/2   down       down   config-incomplete   96     enabled    disabled 

4/1/3   down       down   config-incomplete   96     enabled    disabled 

4/1/4   down       down   config-incomplete   96     enabled    disabled 

4/1/5   down       down   config-incomplete   96     enabled    disabled 

4/1/6   down       down   config-incomplete   96     enabled    disabled 

4/1/7   down       down   config-incomplete   96     disabled   disabled 

4/1/8   down       down   config-incomplete   96     disabled   disabled 

4/1/9   down       down   config-incomplete   96     disabled   disabled 

4/1/10  down       down   config-incomplete   96     disabled   disabled 

4/1/11  down       down   config-incomplete   96     disabled   disabled 

4/1/12  down       down   config-incomplete   96     disabled   disabled 

4/1/13  down       down   config-incomplete   96     disabled   disabled 

4/1/14  down       down   config-incomplete   96     disabled   disabled

Table 5 describes the significant fields shown in the display.

Table 5 show cem summary Field Descriptions 

Field	Description
CEM	Displays the slot, port, and channel number of a CEM channel.
CSTATE	Displays the current state of a CEM channel. The state can be one of the following: •up—The channel is receiving valid packets from a source CEM channel. •down—The channel is receiving no packets (for example, the dejitter buffer is empty). •shutdown—The CEM channel has been administratively shut down.
LSTATE	Displays the current line state of a CEM channel. The line state can be one of the following: •up—The line is ready. •down—The line is down. A T1 or E1 line is down when the line is experiencing a physical-layer failure, such as loss of signal (LOS), loss of multiframe alignment (OOF), or alarm indication signal (AIS). A serial line is down when no cable is attached to the port.
OSTATE	Displays the current operational state of a CEM channel. The operational state can be one of the following: •config-incomplete—The channel is in a config-incomplete state when any of the following conditions exist: –An xconnect is not defined. –A local IP address is not defined. –A local UDP port is not defined. –A remote UDP port is not defined. –The CEM channel is administratively shut down. •enabled—If none of the conditions for the config-incomplete state exists, but the CEM channel is receiving no packets from the remote side, the CEM channel is in an enabled state. •config-mismatch—If packets are arriving from the remote side but with a different payload size, data protection setting, or compression setting, the channel is in the config-mismatch state. •active—The CEM channel is active if none of the conditions outlined above exist.
PSIZE	Payload size configured for the CEM channel, in bytes.
PCOMP	Displays whether payload compression is enabled or disabled for the CEM channel.
DPROT	Displays whether data protection is enabled or disabled for the CEM channel.

Verifying a CEM Network Module Example

The following example displays the status of a configured CEM network module. This example uses the show cem command to monitor the configuration, status and performance of a particular CEM channel.

Router# show cem 4/1/0

cem info

cem 4/1/0 is up

Line state is up

Operational state is active

Near end ip address: 172.31.28.2, udp port: 15901

Far end ip address: 172.31.28.10, udp port: 15901

IP payload size: 512

IP dscp : 0x28

Idle pattern length: 8 , Idle Pattern: 0xFF

Payload compression is disabled

Data protection is disabled

Dejitter buffer size is 60 ms

Channel clock rate is 2048000 bps

Physical interface is E1 unframed

Ingress packets: 32505156, dropped: 0, overruns: 0

Egress packets: 32505158, dropped: 637, lost pkts: 0

Egress out of sequence pkts: 0

Egress overruns: 16, underruns: 244

Egress corrupt pkts rcvd: 0

30 second ingress rate 2050321 bits/sec, 500 packets/sec

30 second egress rate 2050184 bits/sec, 500 packets/sec

Tx interrupts: 32504249

Reorder queue flush: 0, visited: 0, max wait window: 0

Network jitter max: 8 ms, average: 1 ms, min: 0 ms

Adaptive clock ppm correction is 2 tracking

Event history: 0x00230058

Pkts dropped by burst limit: 0

Global stats for slot 4

************************

Egr free buf: 255

Egr host overruns: 0

Egr unknown dest count: 0

Last unknown dest ip : 0.0.0.0, port: 0

Last unknown dest src ip : 0.0.0.0, port: 0

Egr process switched: 0

Egr oos: 0

Egr unknown src count: 0, last unknown src ip: 0.0.0.0, port: 0

Ingr overruns: 0

NM cpu: 53.56 53.51 53.45 53.54

Table 1provides a listing and description of all of the fields displayed by the show cem command. For each line of the display, the middle column of the table indicates whether that line of the display applies to a serial CEM (S), a T1/E1 CEM (TE), or both.

Table 6 show cem Command Output Display

Display Field	Line Type	Description
cem 1/3/1 is up	S, TE	A CEM channel may be either up, down, or shutdown. The channel is up when it is receiving valid packets from a source CEM channel. The channel is down when it is receiving no packets; i.e., the de-jitter buffer is empty. The channel is shutdown when it has been administratively shut down
Line state is up	S, TE	A line state may be either up or down. A T1/E1 line is down when it is experiencing a physical layer failure such as LOS, OOF, AIS, etc.A serial line is down when no cable is attached to the port. Otherwise, the line is up.
Operational state is active	S, TE	The operational state of a CEM channel may be either config-incomplete, enabled, config-mismatch, or active. A CEM channel is in the config-incomplete state if any of the following conditions is true: •an xconnect is not defined •a local IP address is not defined •a local UDP port is not defined •a remote UDP port is not defined •the CEM channel is administratively shut down. If none of the previous conditions is true, but the CEM channel is receiving no packets from the remote side, the channel is in the enabled state. If packets are arriving from the remote side but with a different payload size, data protection setting, or compression setting, the channel is in the config-mismatch state. Otherwise, the channel is active.
Near end ip address: 30.30.30.1, udp port: 16131	S, TE	The local ip addr used to identify the near end (or source router) of a CEM connection must be the same as the remote ip address used to identify the CEM channel at the other end of the CEM connection. If there are multiple CEM connections originating on the same router, they may share the local IP address provided that each connection uses a unique UDP port number
Far end ip address: 40.40.40.1, udp port: 16200	S, TE	The IP address of the remote router. The remote udp port of a CEM channel must be the same as the local udp port of the CEM channel at the other end of the CEM connection.
IP payload size: 64	S, TE	Indicates the nominal bit rate of a serial CEM channel. The actual bit rate may be slightly different depending on whether adaptive clocking is used. See the clock source command for more details.
IP dscp : 0x2E	S, TE	This line is displayed only if DSCP is enabled.
IP dscp is not specified	S, TE	This line is displayed only if DSCP is disabled.
IP prec/tos (tos byte): 0xA0	S, TE	This line is displayed only if DSCP is disabled. Indicates the value specified in the precedence field of the ip precendence command for IP packets originating from this channel and the "type of service" (ToS) bits for the channel. The specified ToS is used in the ToS field of IP packets originating from this channel.
Idle pattern length: 8 , Idle Pattern: 0xFF	S, TE	Indicates the signaling pattern for the transport of Channel Associated Signaling (CAS) bits. It is also used to specify the signaling state for each time slot of a failed CEM channel. Applies only to framed T1 or E1 data channels.
Payload compression is disabled	S, TE	Indicates whether payload compression is configured on the channel. If payload compression is enabled, the CPU is limited to performing payload compression on an aggregate data load of 3 Mbps per network module. Software prevents compression from being enabled on a channel if the resulting aggregate data load to be compressed would exceed 3 Mbps.
Data protection is disabled	S, TE	Indicates whether data protection is enabled or disabled. Thus, each packet contains: •N payload bytes that are repeated from the previous packet, and •N new payload bytes where N is the number of payload bytes specified in the payload-size command. Consequently, when the data protection feature is enabled, the actual payload size of each packet is double the value specified in the payload-size command. Data protection ensures that no data bits are lost in the event of the loss of a single packet. However, data bits are lost if two or more consecutive packets are lost.
Dejitter buffer size is 60 ms	S, TE	Indicates the configured dejitter buffer size. CEM uses a de-jitter buffer at the destination port and holds data in the de-jitter buffer long enough to ensure that the next packet will have arrived before it needs to be played out. The amount of time that the data must be held in the de-jitter buffer is a function of the worst-case delay variation that the packets experience in the network. The de-jitter buffer size determines the connection's ability to tolerate network delay variation. The size of the buffer is specified using the dejitter-buffer command. When a connection is first established (or following any de-jitter buffer under-run), data arriving from the remote side of the connection is held in the de-jitter buffer until it is at least half-full. Then, data playout to the attached CPE is started. Thus, the average delay introduced by the de-jitter buffer is equal to one half the configured size of the de-jitter buffer.
Channel clock rate is 128000 bps	S, TE	Indicates the nominal bit rate of a serial CEM channel. The actual bit rate may be slightly different depending on whether adaptive clocking is used. See the clock source command for more details. For a T1/E1 CEM channel, the clock rate is determined by the definition of the CEM channel and is implicitly defined by the number of time slots used in the CEM channel, as specified in the cem-group command
Clock source is adaptive	S	Indicates how the clock source is defined. For serial CEM channels the clock source command is used. For a T1 or E1 CEM channel the clock source is defined as part of the T1/E1 controller configuration.
Clocking mode is normal	S	Indicates the clocking mode for serial CEM channels as set with the clock mode command. For T1 or E1 CEM channel the clock mode is defined as part of the T1/E1 controller configuration.
Loopback mode is disabled	S	Indicates whether a loopback is configured on the serial interface. not applicable to T1 or E1 lines.
Control lead sampling rate is 0 per second	S	Indicates the sampling rate of input control signals for serial CEM channels. There are no control signals defined on a T1 or E1 channel.
Output control lead states: Active template •cts on •dsr follow remote dtr •dcd on •tm on •ri off Fail template •cts off •dsr off •dcd off •tm off •ri off	S	Indicates the state of each output control signal for serial CEM channels as specified with the control lead state command. There are no control signals defined on a T1 or E1 channel.
Data strobe is not configured	S	Indicates whether an input control signal for monitoring valid data has been configured. If a data strobe is specified, data is packetized and sent to the other end ONLY when the specified control signal is in the specified state. When the specified control signal is NOT in the specified state, input data is ignored and no data packets are sent across the network for this channel. This capability is used to save bandwidth when the attached CPE is inactive.
Signaling is disabled	TE	Indicates whether signaling for the transport of Channel Associated Signaling (CAS) bits is configured for framed T1 or E1 data channels.
Physical interface is T1 channelized	TE	The physical interface may be one of: - T1 channelized - T1 unframed - E1 channelized - E1 unframed
Physical interface is RS449 DCE	S	The serial physical interface is determined by the type of cable attached. Refer to the hardware documentation for the network module for valid cable types.
Ingress packets: 215513, dropped: 0, overruns: 0	S,TE	Ingress packets is the number of packets created and sent into the network. Ingress packets dropped is the number of ingress packets that were discarded because the PCI bus to the host CPU was too busy. Ingress overruns is the number of times one or more packets were discarded because the network module's CPU was too busy to process the ingress packets.
Egress packets: 12190, dropped: 0, lost pkts: 0	S,TE	Egress packets is the number of packets received from the network and sent to the attached CPE. Egress packets dropped is the number of valid egress packets that were received but were dropped for any reason (egress de-jitter buffer overflow, lack of egress data clock, etc.) Egress lost pkts is the number of egress packets that were never received as determined by a gap in the sequence numbers of the arriving packets.
Egress out of sequence pkts: 0	S, TE	This is the number of egress packets received out of order as determined by the sequence numbers of the arriving packets.
Egress overruns: 0, underruns: 0	S, TE	Egress overruns is the number of times the egress de-jitter buffer overflowed. Egress underruns is the number of times the egress de-jitter buffer experienced an under-run.
Egress corrupt pkts rcvd: 0	S, TE	This is the number of egress packets received but discarded because the CEoIP header on the packet was found to be inconsistent or corrupt.
30-second ingress rate 128034 bits/sec, 250 packets/sec	S, TE	This is the ingress data rate of the most-recent 30 seconds, in bits/second and in packets/second, measured relative to the local oscillator. The packet rate is measured, but only the integer portion of the measurement is shown. The packets counted include the data packets as well as any control signal update packets or any CAS signaling packets. The bit rate is not measured independently. It is calculated from the measured packet rate. The calculation assumes that all packets have the same payload size as the data packets. In fact, control signal update packets and CAS signaling packets do not have the same payload size as the data packets. Therefore, the displayed bit rate is too large if control signal update packets or CAS signaling packets are included in the packet rate.
30 second egress rate 128034 bits/sec, 250 packets/sec	S, TE	This is the egress data rate of the most-recent 30 seconds, in bits/second and in packets/second, measured relative to the local oscillator. The packet rate is measured, but only the integer portion of the measurement is shown. The packets counted include the data packets as well as any control signal update packets or any CAS signaling packets. The bit rate is not measured independently. It is calculated from the measured packet rate. The calculation assumes that all packets have the same payload size as the data packets. In fact, control signal update packets and CAS signaling packets do not have the same payload size as the data packets. Therefore, the displayed bit rate is too large if control signal update packets or CAS signaling packets are included in the packet rate.
Tx interrupts: 12183	S, TE	This is the number of packets transmitted to the attached CPE. Normally, this should equal the Egress Packets above. If these two numbers are significantly different, this indicates some type of internal hardware or software failure.
Reorder queue flush: 0, visited: 0, max wait window: 0	S, TE	These counters pertain to the processing of packets that arrive out of sequence. Reorder queue flush is the number of missing packets. Reorder queue visited is the number of times that a packet was received out of sequence. Reorder queue max wait window is the maximum sequence number offset of any packet that was received out of sequence.
Network jitter max: 7 ms, average: 3 ms, min: 1 ms	S, TE	These measurements are not really jitter measurements. They are measurements of the inter-packet arrival times. Network jitter max is the integer portion of the maximum inter-packet arrival time. Network jitter average is the integer portion of the average inter-packet arrival time. Network jitter min is the integer portion of the minimum inter-packet arrival time.
Adaptive clock ppm correction is 9 tracking	S, TE	This line is displayed only if the CEM channel is configured for Adaptive Clock. It shows the integer portion of the current clock adjustment, in parts per million (ppm), relative to the local reference oscillator. The adaptive clock may be in either the tuning state or the tracking state.
Control Link state: Active	S	This line is displayed only if the control signal sampling rate on this CEM channel is configured to a non-zero value. It specifies whether the Active or the Fail interface control template (as described in Section 9.2.3.9) is currently being applied. The control link state may be in either the Active or Down state. The control link state is Down any time the CEM channel's de-jitter buffer is found to be empty at two consecutive samplings of the channel's ingress control signals. At such times, the CEM channel is down and the Fail interface control template is applied. At all other times, the control link state is Active and the active interface control template is applied.
Input control lead states: •rts = off •dtr = off •ll = off •rl = off	S	This line is displayed only if the control signal sampling rate on this CEM channel is configured to a non-zero value. It shows the current state of each of the INPUT control signals on this serial port.
Event history: 0x002B0000	S, TE	For Engineering debug purposes only.
Pkts dropped by burst limit: 0	S, TE	For Engineering debug purposes only.
Global stats for slot 1
Egr free buf: 256	S, TE	For Engineering debug purposes only.
Egr host overruns: 0	S, TE	For Engineering debug purposes only.
Egr unknown dest count: 0	S, TE	The Egr unknown dest count is the number of egress packets received with an unassigned destination UDP port.
Last unknown dest ip : 0.0.0.0, port: 0	S, TE	The last unknown dest ip is the destination IP address in the most-recently received packet with an unassigned destination UDP port. The last unknown dest port is the destination UDP port in the most-recently received packet with an unassigned destination UDP port.
Last unknown dest src ip : 0.0.0.0, port: 0	S, TE	The last unknown dest src ip is the source IP address in the most-recently received packet with an unassigned destination UDP port. The last unknown dest src port is the destination UDP port in the most-recently received packet with an unassigned destination UDP port.
Egr process switched: 0	S, TE	This is the number of egress packets that were process switched by the host router. For Engineering debug purposes only.
Egr oos: 0	S, TE	Not used.
Egr unknown src count: 0, last unknown src ip: 0.0.0.0, port: 0	S, TE	The Egr unknown src count is the number of egress packets received with a valid destination IP address and UDP port number but with an invalid source IP address or invalid source UDP port. The last unknown src ip is the source IP address in the most-recently received packet from an unknown source. The last unknown src port is the source UDP port in the most-recently received packet from an unknown source.
Ingr overruns: 0	S, TE	This is the number of packets dropped because the host router's CPU was too busy to process the packets.
NM cpu: 46.22 46.22 46.22 46.22	S,TE	This displays the percentage of the network module CPU's time that is consumed. Four consecutive eight-second intervals are shown. The most-recent eight second interval is shown first.

You can clear all of the CEM channel statistics and restart statistics collection using the clear cem command. The following examples shows counters being cleared with the clear cem command.

Router# clear cem 1/3/1 

Cleared counters for cem 1/3/1. 

Router# clear cem all 

Cleared counters for cem 1/1/0. Cleared counters for cem 1/3/1. Cleared counters for cem 
2/0/0. Cleared counters for cem 2/1/0. Cleared counters for cem 2/2/0. Cleared counters 
for cem 2/3/0. 

Related Commands

Commands	Description
cem	Enters circuit emulation configuration mode.
clear cem	Clears CEM statistics.

signaling

To enable channel-associated signaling (CAS), use the signaling command in CEM configuration mode. To disable signaling, use the no form of this command.

signaling [on-hook-pattern] [off-hook-pattern] [msec]

no signaling [on-hook-pattern] [off-hook-pattern] [msec]

Syntax Description

on-hook-pattern	(Optional) Specifies the ABCD signaling bits sent to the attached device (typically a PBX) to simulate the remote PBX sending notification that any call in progress has been terminated or is on-hook. The T1 default is 5 hex. The E1 default is D hex.
off-hook-pattern	(Optional) Specifies the ABCD signaling bits sent to the attached device (typically a PBX) to simulate the remote PBX sending notification that a channel is already in use, or is off-hook. The T1 default is F hex. The E1 default is 5 hex.
msec	(Optional) Specifies the time, in milliseconds, between the onhook and offhook patterns. Values are in the range from 50 to 5000. Default is 2000. Any value entered is rounded up to the next multiple of 50 milliseconds.

Command Default

CAS is disabled.

Command Modes

CEM configuration

Command History

Release	Modification
12.3(7)T	This command was introduced.
12.3(7)T1	The on-hook-pattern, off-hook-pattern, and msec arguments were added.

Usage Guidelines

When a T1/E1 channel with signaling enabled is placed in the failed state, the on-hook pattern is sent to the attached device for a duration specified by the msec attribute. After the time specified by the msec attribute, the off-hook pattern is sent to the attached device for as long as the CEM connection remains failed.

The on-hook pattern parameter specifies, as a single hexadecimal character, the ABCD signaling bits sent to the attached device (typically a PBX) to simulate the remote PBX sending notification that any call in progress has been terminated or is on-hook. This provides a forced disconnect of any calls when the CEM connection fails.

The off-hook pattern parameter specifies, as a single hexadecimal character, the ABCD signaling bits sent to the attached device (typically a PBX) to simulate the remote PBX sending notification that a channel is already in use, or is off-hook. This prevents the attached PBX from trying to use the failed channel to place a new call while the CEM connection remains failed.

Examples

The following example shows how to enable signaling.

Router(config-cem)# signaling

The following example shows how to enable signaling with onhook and offhook parameters:

Router(config-cem)# signalling 0x0 0x1 101

Delay will be set to 150 ms

Related Commands

Command	Description
cem	Enters circuit emulation configuration mode.
failure	Specifies a time period before a CEM connection enters, or recovers from, a failed state.
show cem	Displays CEM channel statistics.

xconnect (CEM)

To build one end of a circuit emulation (CEM) connection and to enter CEM xconnect configuration mode, use the xconnect command in CEM configuration mode. To remove any existing CEM connections from this CEM channel, use the no form of this command.

xconnect remote-ip-address virtual-connect-ID encapsulation encapsulation-type

no xconnect

Syntax Description

remote-ip-address	IP address of an interface—physical or loopback—on the destination router.
virtual-connect-ID	Virtual connect ID (VCID). For CEM over IP (CEoIP), you must enter a value of 0.
encapsulation	Sets the encapsulation type.
encapsulation-type	Encapsulation type. You must set the encapsulation type to UDP.

Command Default

No CEM connections are built.

Command Modes

CEM configuration

Command History

Release	Modification
12.3(7)T	This command was introduced.

Examples

The following example shows how to build one end of a CEoIP connection and to enter CEM xconnect configuration mode.

Router(config-cem)# xconnect 10.0.5.1 0 encapsulation udp

Router(config-cem-xconnect)# 

Related Commands

Command	Description
cem	Enters circuit emulation configuration mode.
local ip address	Defines the IP address of the local router.
local udp port	Defines the local UDP port.
remote udp port	Defines the UDP port of a remote endpoint.
show cem	Displays CEM channel statistics.

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