Cisco IOS XR Interface and Hardware Component Configuration Guide for the Cisco XR 12000 Series Router, Release 4.3.x

Configuring Circuit Emulation over Packet on Cisco IOS XR Software

This module describes the configuration of Circuit Emulation over Packet (CEoP) shared port adapters (SPAs) on the Cisco XR 12000 Series Router.

Feature History for Configuring CEoP on Cisco XR 12000 Series Router

Contents

•Prerequisites for Configuration

•Overview of Circuit Emulation over Packet Service

•Information About Configuring CEoP Channelized SONET/SDH

•Clock Distribution

•Mode Change for CEoP SPA

•How to implement CEM

•Configuring Clocking

•Configuration Examples for CEM

•Additional References

Prerequisites for Configuration

You must be in a user group associated with a task group that includes the proper task IDs. The command reference guides include the task IDs required for each command. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Before configuring the Circuit Emulation over Packet (CEoP) service on your router, ensure that these conditions are met:

•You must have one of these SPAs installed in your chassis:

–Cisco 1-port Channelized OC3/STM-1 Circuit Emulation and Channelized ATM SPA

–Cisco 2-Port Channelized T3/E3 Circuit Emulation and Channelized ATM SPA

–Cisco 24-Port Channelized T1/E1 Circuit Emulation and Channelized ATM SPA

•You should know how to apply and specify the SONET controller name and interface-path-id with the generalized notation rack/slot/module/port. The SONET controller name and interface-path-id are required with the controller sonet command.

•You should know how to apply and specify the T3/E3 and T1/E1 controller name and interface-path-id with the generalized notation rack/slot/module/port. The T3/E3, T1/E1 controller name and interface-path-id are required with the controller {T3|E3|T1|E1} command.

Overview of Circuit Emulation over Packet Service

Circuit Emulation over Packet (CEoP) is a way to carry TDM circuits over packet switched network. Circuit Emulation over Packet is the imitation of a physical connection. The goal of CEoP is to replace leased lines and legacy TDM networks. This feature allows network administrators to use their existing IP/MPLS network to provide leased-line emulation services or to carry data streams or protocols that do not meet the format requirements of other multiservice platform interfaces. CEoP puts TDM bits into the packets, encapsulates them into appropriate header and then sends through PSN. The receiver side of CEoP restores the TDM bit stream from packets.

CEoP SPAs are half-height (HH) Shared Port Adapters (SPA) and the CEoP SPA family consists of 24xT1/E1/J1, 2xT3/E3, and 1xOC3/STM1 unstructured and structured (NxDS0) quarter rate, half height SPAs. The CEoP SPAs provide bit-transparent data transport that is completely protocol independent.

CEoP has two major modes:

•Unstructured mode is called SAToP (Structure Agnostic TDM over Packet) — SAToP does not look what is inside the incoming data and considers it as a pure bit stream.

•Structured mode is named CESoPSN (Circuit Emulation Service over Packet Switched Network) — CESoPSN is aware of the structure of the incoming TDM bit stream at DS0 level.

CESoPSN and SAToP can use MPLS, UDP/IP, and L2TPv3 for the underlying transport mechanism.

Note The Cisco IOS XR Release 4.2.0 supports only MPLS transport mechanism.

These SPAs are the first Cisco router interfaces designed to meet the emerging standards for Circuit Emulation Services over Packet Switched Network (CESoPSN) and Structure-Agnostic Transport over Packet (SAToP) transport.

In Cisco IOS XR Release 4.2.0, the CEM functionality is supported on the following CEoP SPAs:

•Cisco 1-port Channelized OC3/STM-1 Circuit Emulation and Channelized ATM SPA

•Cisco 2-Port Channelized T3/E3 Circuit Emulation and Channelized ATM SPA

•Cisco 24-Port Channelized T1/E1 Circuit Emulation and Channelized ATM SPA

In SAToP mode, these SPAs do not assume that data has any predefined format or structure. They simply regard the data as an arbitrary bit stream. All data bits are simply transported to a defined destination encapsulated in IP/MPLS packets. In CESoPSN mode the carrier has defined format. The SPAs support a full range of E1 and T1 framing. CESoPSN applications can save utilized bandwidth by selecting only valid timeslots for transmission. Some primary applications include:

•Transporting 2G and 3G network traffic over packet networks, for mobile operators. Mobile service providers are implementing high-speed data networks with HSDPA to support new revenue-generating services. The SPA is uniquely positioned for multigenerational migration of mobile networks (2G and 3G), simultaneously carrying TDM and ATM traffic over IP/MPLS networks. This technology provides a mechanism to enable IP/MPLS to the cell site, which can eventually be in place to transport the mobile traffic over IP from end to end.

•T3/E3 circuit emulation for leased-line replacement.

•T1/E1 circuit emulation for leased-line replacement.

•PBX to PBX connectivity over PSN.

•High density SS7 backhaul over IP/MPLS.

•Inter-MSC connectivity.

•Preencrypted data for government, defense, or other high-security applications.

•Proprietary synchronous or asynchronous data protocols used in transportation, utilities, and other industries.

•Leased-line emulation service offerings in metropolitan (metro) Ethernet or WAN service provider environments.

For more information on Circuit Emulation service concepts, configuration, and example, see the Implementing MPLS Layer 2 VPNs module in the Cisco IOS XR Virtual Private Network Configuration Guide for the Cisco XR 12000 Series Router.

Information About Configuring CEoP Channelized SONET/SDH

To configure the Circuit Emulation over Packet Channelized SONET/SDH, you must understand the following concepts:

•Channelized SONET and SDH Overview

•Default Configuration Values for Channelized SONET/SDH

Channelized SONET and SDH Overview

Synchronous Optical Network (SONET) is an American National Standards Institute (ANSI) specification format used in transporting digital telecommunications services over optical fiber.

Channelized SONET provides the ability to transport SONET frames across multiplexed T3/E3 and virtual tributary group (VTG) channels.

The Cisco 1-port Channelized OC3/STM-1 Circuit Emulation and Channelized ATM SPA does not support the following modes:

• Clear Channel OC3

• Clear Channel E3

• Clear Channel T3

SONET uses Synchronous Transport Signal (STS) framing. An STS is the electrical equivalent to an optical carrier 1 (OC-1).

A channelized SONET interface is a composite of STS streams, which are maintained as independent frames with unique payload pointers. The frames are multiplexed before transmission.

When a line is channelized, it is logically divided into smaller bandwidth channels called paths. These paths carry the SONET payload. The sum of the bandwidth on all paths cannot exceed the line bandwidth.

When a line is not channelized, it is called clear channel, and the full bandwidth of the line is dedicated to a single channel that carries broadband services.

Channelizing a SONET line consists of two primary processes:

•Configuring the controller

•Configuring the interface into channelized paths

You configure the controller first by setting the mode of the STS path.

When the mode is specified, the respective controller is created, and the remainder of the configuration is applied on that controller. For example, mode T3 creates a T3 controller. The T3 controller can then be configured to a serial channel, or it can be further channelized to carry T1s, and those T1s can be configured to serial interfaces.

The Cisco 1-Port Channelized OC-3/STM-1 Circuit Emulation and Channelized ATM SPA does not support the following modes:

•Clear Channel OC3

•Clear Channel E3

•Clear Channel T3

On a Cisco 1-Port Channelized OC-3/STM-1 SPA, the default configuration consists of the following paths that are already configured when the SONET card is installed.

•STS 1

•STS 2

•STS 3

Each STS path can be independently configured into T3s, E3s, or VTGs, and so on.

Depending on the support for your installed SPA, each STS path can be independently configured into T3s, E3s, or VTGs, and so on.The following level of SONET channelization modes are supported in CEoP SPA:

OC3->STS-1->VTG-> VT1.5 -> Unframed T1

OC3->STS-1->VTG-> VT1.5 -> T1 -> DS0

Figure 19 shows the VTG paths that can be configured.

Note Only VTG paths are supported on the Cisco 1-Port Channelized OC-3/STM-1 SPA on the Cisco XR12000 Series Router.

Figure 19 SONET VTG Channelized Paths

Synchronous Digital Hierarchy (SDH) is the international equivalent of SONET.

SDH uses Synchronous Transport Mode (STM) framing. An STM-1 is the electrical equivalent to 3 optical carrier 1s (OC-1s). A Synchronous Transport Module (STM) signal is the Synchronous Digital Hierarchy (SDH) equivalent of the SONET STS, but the numbers are different for each bandwidth. In this guide, the STM term refers to both path widths and optical line rates. The paths within an STM signals are called administrative units (AUs).

A summary of the basic terminology differences between SONET and SDH is as follows:

•SONET STS is equivalent to SDH administrative unit (AU)

•SONET VT is equivalent to SDH tributary unit (TU)

•SDH basic building blocks are STM-1 (equivalent to STS-3) and STM-0 (equivalent to STS-1)

An administrative unit (AU) is the information structure that provides adaptation between the higher-order path layer and the multiplex section layer. It consists of an information payload (the higher-order virtual container) and an administrative unit pointer, which indicates the offset of the payload frame start relative to the multiplex section frame start.

An AU can be channelized into tributary units (TUs) and tributary unit groups (TUGs).

An administrative unit 4 (AU-4) consists of three STM-1s or an STM-3.

An administrative unit 3 (AU-3) consists of one STM-1.

An administrative unit group (AUG) consists of one or more administrative units occupying fixed, defined positions in an STM payload.

The Table 7 shows the commonly used notations and terms in SONET standards and their SDH equivalents.

These are the levels of SDH channelization that are supported on the CEoP SPA:

•For E1 :

–STM1-> AU-4 -> TUG-3 -> TUG-2 ->VC12-> Unframed E1

–STM1-> AU-4 -> TUG-3 -> TUG-2 ->VC12-> E1 -> DS0

•For T1 :

–STM1-> AU-3-> TUG-2 -> VC11->Unframed T1

–STM1-> AU-3-> TUG-2 -> VC11->T1 -> DS0

Figure 20 shows an example of SDH AU-3 paths that can be configured on the CEoP SPA.

Figure 20 SDH AU3 Paths

Figure 21 shows the SDH AU4 paths that can be configured on the CEoP SPA.

Figure 21 SDH AU4 Paths

Default Configuration Values for Channelized SONET/SDH

Table 8 describes the default configuration parameters that are present on the Channelized SONET/SDH.

Clock Distribution

Clocking distribution in the CEoP SPA can be done in these ways:

•Synchronous Clocking — With synchronous clocking, TDM lines on source and destination are synchronized to the same clock delivered by some means of physical clock distribution (SONET/SDH, BITS, GPS, and so on). The clock to the particular TDM line can be delivered from

–Line: the transmit clock is from the receiver of the same physical line

– Internal: the transmit clock is taken from line card and can be derived either from an internal free running oscillator or from another physical line

–Recovered: In-band pseudowire-based activeclock recovery on a CEM interface which is used to drive the transmit clock

The number of recovered clocks that can be configured for CEoP SPA are:

–Cisco 24-Port Channelized T1/E1 Circuit Emulation and Channelized ATM SPA : 24 clocks for each SPA.

–Cisco 2-Port Channelized T3/E3 Circuit Emulation and Channelized ATM SPA : 10 clocks for each SPA in the T1/E1 mode and 2 clocks for each SPA in the T3/E3 mode.

–Cisco 1-port Channelized OC3/STM-1 Circuit Emulation and Channelized ATM SPA : 10 clocks per SPA in the T1/E1 mode.

•Adaptive Clocking — Adaptive clocking is used when the routers do not have a common clock source. See Figure 22. The clock is derived based on packet arrival rates. Two major types of adaptive clock recovery algorithms are:

–Based on dejitter buffer fill level

–Based on packet arrival rate

The clock quality depends on packet size, has less tolerance to packet loss/corruption and introduces unnecessary delay in order to have sufficient number of packets in the buffer for clock recovery. The dejitter buffer size determines the ability of the emulated circuit to tolerate network jitter. The dejitter buffer in CEoP software is configurable up to a maximum of 500 milliseconds.

Note The CEoP SPA hardware supports only the packet arrival rate algorithm.

Figure 22 Adaptive Clock Recovery

Note CEM supports only adaptive clocking in the Cisco XR 12000 Series Router.

For a sample CEM interface configuration, refer Circuit Emulation Interface Configuration: Examples.

Mode Change for CEoP SPA

This section explains about the command to change the mode of operation of CEoP SPA. At any specific instance, only one of this feature combination is possible on all the CEoP SPAs:

•Combination 1 : ATM + IMA + L3QoS

•Combination 2 : ATM + IMA + CEM

The hw-module subslot nodeid mode CEM command is introduced in Cisco XR 12000 Series Router to configure the modes. The ATM + IMA + L3QoS is the default mode. These sections describe two scenarios for both the mode combinations.

Host is configured and SPA is running in ATM + IMA + CEM mode

When L3QoS is configured on an ATM / IMA interface and committed, the commit operation fails, as the mode is CEM mode.

When the hw-module subslot nodeid mode CEM command is executed to switch the mode to ATM + IMA + L3QoS mode, with CEM configuration already present in running configuration, the commit fails with the message that CEM needs to be unconfigured before the change of mode to ATM + IMA + L3QoS. You must manually remove the CEM configuration before the SPA can be reloaded and booted in this new mode.

Host is configured and SPA is running in ATM + IMA + L3QoS mode

When CEM is configured and committed, the commit operation fails, as the mode is L3QoS mode.

When the hw-module subslot nodeid mode CEM command is executed to switch the mode to ATM + IMA + CEM mode, with L3QoS configuration already present in running configuration, the commit fails with the message that L3QoS needs to be unconfigured before the change of mode to ATM + IMA + CEM. You must manually remove the L3QoS configuration before the SPA can be reloaded and booted in this new mode.

The Table 9 shows the support for L3QoS functionality on the three CEoP SPAs.

How to implement CEM

This section contains the following procedures:

•Configuring SONET VT1.5-Mapped T1 Channels and Creating CEM Interface

•Configuring SDH AU-3 Mapped to C11-T1 or C12-E1

•Configuring the Cisco 24-Port Channelized T1/E1 Circuit Emulation and Channelized ATM SPA and Creating CEM Interface

•Configuring the Cisco 2-Port Channelized T3/E3 Circuit Emulation and Channelized ATM SPA and Creating CEM Interface

•Configuring CEM Interface

•Configuring Clocking

•Show Commands for CEM

Configuring SONET VT1.5-Mapped T1 Channels and Creating CEM Interface

In the case of Cisco 1-port Channelized OC3/STM-1 CEoP SPA, the STS stream can be channelized into the VT1.5 mapped T1 channel.

This task explains how to configure a SONET line into VT-mapped T1 Channels.

Prerequisites

None.

Restrictions

Channelized SONET STS stream with VT1.5-T1 mapping is supported on the following SPA:

•Cisco 1-Port Channelized OC-3/STM-1 SPA

SUMMARY STEPS

1. configure

2. hw-module subslot node-id cardtype type

3. hw-module subslot node-id mode CEM

4. commit

5. controller sonet interface-path-id

6. sts number

7. mode mode

8. root

9. controller t1 interface-path-id

10. cem-group unframed

11. controller t1 interface-path-id

12. cem-group framed group-number timeslots range1-range2

13. no shutdown

14. end
or
commit

15. show runn interface cem interface-path-id

DETAILED STEPS

root

Uncommitted changes found, commit them before 
exiting(yes/no/cancel)? 

[cancel]:

Configuring SDH AU-3 Mapped to C11-T1 or C12-E1

This section includes the following tasks:

•Configuring SDH AU-3 Mapped to C11-T1 and Creating CEM Interface

•Configuring SDH AU-3 Mapped to C12-E1 and Creating CEM Interface

Configuring SDH AU-3 Mapped to C11-T1 and Creating CEM Interface

This task explains how to configure SDH AU-3 with c11-t1 mapping.

Prerequisites

•You should know how to configure the SONET/SDH controller.

Restrictions

Channelized SDH AU-3 with c11-t1 mapping is supported on the following SPA:

•Cisco 1-Port Channelized OC-3/STM-1 SPA

SUMMARY STEPS

1. configure

2. hw-module subslot node-id cardtype type

3. hw-module subslot node-id mode CEM

4. commit

5. controller sonet interface-path-id

6. au number

7. mode mode

8. root

9. controller t1 interface-path-id

10. cem-group unframed

11. controller t1 interface-path-id

12. cem-group framed group-number timeslots range1-range2

13. no shutdown

14. end
or
commit

15. show runn interface cem interface-path-id

DETAILED STEPS

root

Uncommitted changes found, commit them before 
exiting(yes/no/cancel)? 

[cancel]:

Configuring SDH AU-3 Mapped to C12-E1 and Creating CEM Interface

This task explains how to configure SDH AU-3 with c12-e1 mapping.

Prerequisites

•You should know how to configure the SONET/SDH controller.

Restrictions

Channelized SDH AU-3 with c12-e1 mapping is supported on the following SPAs:

•Cisco 1-Port Channelized OC-3/STM-1 SPA

SUMMARY STEPS

1. configure

2. hw-module subslot node-id cardtype type

3. hw-module subslot node-id mode CEM

4. commit

5. controller sonet interface-path-id

6. au number

7. mode tug3

8. width number

9. tug3 number

10. mode mode

11. root

12. controller e1 interface-path-id

13. cem-group unframed

14. controller e1 interface-path-id

15. cem-group framed group-number timeslots range1-range2

16. no shutdown

17. end
or
commit

DETAILED STEPS

root

Uncommitted changes found, commit them before 
exiting(yes/no/cancel)? 

[cancel]:

Configuring the Cisco 24-Port Channelized T1/E1 Circuit Emulation and Channelized ATM SPA and Creating CEM Interface

This task explains how to configure the Cisco 24-Port Channelized T1/E1 Circuit Emulation and Channelized ATM SPA.

SUMMARY STEPS

1. configure

2. hw-module subslot node-id cardtype type

3. hw-module subslot node-id mode CEM

4. commit

5. controller t1 interface-path-id

6. cem-group unframed

7. controller t1 interface-path-id

8. cem-group framed group-number timeslots range1-range2

9. no shutdown

10. end
or
commit

11. show runn interface cem interface-path-id

DETAILED STEPS

Uncommitted changes found, commit them before 
exiting(yes/no/cancel)? 

[cancel]:

Configuring the Cisco 2-Port Channelized T3/E3 Circuit Emulation and Channelized ATM SPA and Creating CEM Interface

T3/E3 Channelization Mode

This task explains how to configure the Cisco 2-Port Channelized T3/E3 Circuit Emulation and Channelized ATM SPA using T3/E3 channelization.

Note The T3/E3 channels can be channelized further into T1s or E1s, and the T1s or E1s can be channelized into time slots (DS0s), on the Cisco 2-Port Channelized T3/E3 Circuit Emulation and Channelized ATM SPA.

SUMMARY STEPS

1. configure

2. hw-module subslot node-id cardtype type

3. hw-module subslot node-id mode CEM

4. commit

5. controller {t3 | e3} interface-path-id

6. cem-group unframed

7. no shutdown

8. end
or
commit

9. show runn interface cem interface-path-id

DETAILED STEPS

Uncommitted changes found, commit them before 
exiting(yes/no/cancel)? 

[cancel]:

T1/E1 Channelization Mode

This task explains how to configure the Cisco 2-Port Channelized T3/E3 Circuit Emulation and Channelized ATM SPA using T1/E1 channelization.

SUMMARY STEPS

1. configure

2. hw-module subslot node-id cardtype type

3. hw-module subslot node-id mode CEM

4. commit

5. controller t3 interface-path-id

6. mode {t1|e1}

7. controller t1 interface-path-id

8. cem-group unframed

9. controller t1 interface-path-id

10. cem-group framed group-number timeslots range1-range2

11. no shutdown

12. end
or
commit

13. show runn interface cem interface-path-id

DETAILED STEPS

Uncommitted changes found, commit them before 
exiting(yes/no/cancel)? 

[cancel]:

Configuring CEM Interface

This section provides information about how to configure CEM. CEM provides a bridge between a time-division multiplexing (TDM) network and a packet network using Multiprotocol Label Switching (MPLS). The router encapsulates the TDM data in the MPLS packets and sends the data over a CEM pseudowire to the remote provider edge (PE) router.

The following sections describe how to configure CEM:

•Configuration Guidelines and Restrictions

•Configuring a Global CEM Class

•Attaching a CEM Class

•Configuring Payload Size

•Setting the Dejitter Buffer Size

•Setting an Idle Pattern

•Enabling Dummy Mode

•Setting a Dummy Pattern

Configuration Guidelines and Restrictions

Not all combinations of payload size and dejitter buffer size are supported. If you apply an incompatible payload size or dejitter buffer configuration, the router rejects it and reverts to the previous configuration.

Configuring a Global CEM Class

This task explains how to configure a global CEM class.

Note Any interface configuration would have higher precedence over configuration applied through attaching a CEM class. Also, CEM class attached to an interface would have higher precedence than CEM class attached to the parent controller. For example, if the dummy pattern value of 0xcf is applied directly to an interface and then a CEM class which contains dummy pattern value of 0xaa is attached to the same interface, then the dummy pattern value would be 0xcf. The new configuration would not be applied until the dummy pattern value applied directly to the interface is removed.

SUMMARY STEPS

1. configure

2. cem class class-name

3. payload value

4. dejitter value

5. idle pattern value

6. dummy mode {last-frame | user-defined}

7. dummy pattern value

8. end
or
commit

DETAILED STEPS

Uncommitted changes found, commit them before 
exiting(yes/no/cancel)? 

[cancel]:

Attaching a CEM Class

This task explains how to attach a global CEM class.

Note You can attach a CEM class either to a CEM interface or to a T1/E1 controller.

SUMMARY STEPS

1. configure

2. interface cem interface-path-id (or) controller {t1|e1} rack/slot/subslot/port

3. cem class-attach class-name

4. end
or
commit

DETAILED STEPS

Uncommitted changes found, commit them before 
exiting(yes/no/cancel)? 

[cancel]:

Configuring Payload Size

To specify the number of bytes encapsulated into a single IP packet, use the cem payload command. The size argument specifies the number of bytes in the payload of each packet. The range is from 32 to 1312 bytes.

Default payload sizes for an unstructured CEM channel are as follows:

•E1 = 256 bytes

•T1 = 192 bytes

•E3 = 1024 bytes

•T3 = 1024 bytes

Default payload sizes for a structured CEM channel depend on the number of time slots that constitute the channel. Payload (L in bytes), number of time slots (N), and packetization delay (D in milliseconds) have the following relationship: L = 8*N*D.

The default payload size is calculated using the packetization latency depending on the number of time slots the cem interface represents. The relationship between the number of time slots and the packetization latency is provided below:

•For N = 1, D is 8 milliseconds (with the corresponding packet payloadsize of 64 bytes)

•For 2 <=N <= 4, D is 4 milliseconds (with the corresponding packetpayload size of 32*N bytes)

•For N >= 5, D is 1 millisecond (with the corresponding packet payloadsize of 8*N octets).

Support of 5 ms packetization latency for N = 1 is recommended.

Setting the Dejitter Buffer Size

To specify the size of the dejitter buffer used to compensate for the network filter, use the cem dejitter command. The configured dejitter buffer size is converted from milliseconds to packets and rounded up to the next integral number of packets. Use the size argument to specify the size of the buffer, in milliseconds. The range is from 1 to 500 ms. The following is an example:

Router(config-cem)# cem dejitter 5

The default dejitter buffer for a CEM channel, irrespective of CESoPSN or SAToP, is as follows:

•E1 = 16 milliseconds

•T1 = 16 milliseconds

•E3 = 5 milliseconds

•T3 = 5 milliseconds

Note Refer Table 10, Table 11, and Table 12 for the relationship between payload and dejitter buffer on SAToP T1/E1, T3/E3, and CESoPSN lines. Configuration of payload and dejitter should be in accordance with the minimum and maximum values as mentioned in the table.

Note The maximum and minimum dejitter buffer value, that is the range is fixed for a given payload value.

Setting an Idle Pattern

To specify an idle pattern, use the [no] cem idle pattern pattern command. The payload of each lost CESoPSN data packet must be replaced with the equivalent amount of the replacement data. The range for pattern is from 0x0 to 0xff; the default idle pattern is 0xff. This is an example:

Router(config-cem)# cem idle pattern 0xff

If the expected CEM packets are not received for a given CEM interface and are considered as being lost, then the CEoP SPA will play out the idle pattern towards the TDM attachment circuit in the respective timeslots configured in the CEM group.

Enabling Dummy Mode

Dummy mode enables a bit pattern for filling in for lost or corrupted frames. To enable dummy mode, use the cem dummy mode [last-frame | user-defined] command. The default is last-frame. This is an example:

Router(config-cem)# cem dummy mode last-frame 

When packets are lost due to misordering or where reordering of packets is not successful, the CEoP SPA will play out the Dummy pattern towards the TDM attachment circuit in respective timeslots configured in the CEM group.

Setting a Dummy Pattern

If dummy mode is set to user-defined, you can use the cem dummy-pattern command to configure the dummy pattern. The range for pattern is from 0x0 to 0xff. The default dummy pattern is 0xff. This is an example:

Router(config-cem)# cem dummy-pattern 0xff 

The Table 10 shows the relationship between payload and dejitter for T1/E1 SAToP lines.

Table 10 T1/E1 SAToP lines:

Payload and Jitter Limits

The Table 11 shows the relationship between payload and dejitter for T3/E3 SAToP lines.

Table 11 T3/E3 SAToP lines:

Payload and Jitter Limits

The Table 12 shows the relationship between payload and dejitter for DS0 lines.

Table 12

CESoPSN DS0 Lines: Payload and Jitter Limits

Configuring Clocking

Each SPA port shall be configured either to use system clock from the host card or loop timed independently. Each SPA also supplies a reference clock to the host which can be selected among the received port clocks. This section provides information about how to configure clocking on the 1xOC3, 24xT1/E1 and 2xT3/E3 SPA.

This section describes the following topics:

•Configuring Clock Recovery

•Verifying Clock recovery

Configuring Clock Recovery

When configuring clock recovery, consider the following guidelines:

Adaptive Clock Recovery

•Clock source:

–In Cisco IOS XR Release 4.2.0 and later, recovered clock from a CEM interface on the 1-Port Channelized OC-3/STM1 CEoP SPA, 24xT1/E1 CEoP SPA and 2xT3/E3 CEoP SPA can be used as a clock source on the SPA itself.

•Number of clock sources allowed:

–Refer the section Clock Distribution for more information.

•The minimum bundle size of CEM pseudowires on the network that delivers robust clock recovery is 4 DS0s.

•The minimum packet size of CEM pseudowires on the network that delivers robust clock recovery is 64 bytes.

To configure clock recovery on the CEoP SPA and to apply the recovered clock to the controller, use the following procedure:

SUMMARY STEPS

1. configure

2. interface cem rack/slot/subslot/port:cem-group

3. recover-clock clock-id {adaptive}

4. controller {t1|e1|t3|e3} rack/slot/subslot/port

5. clock source recovered clock-id

DETAILED STEPS

Verifying Clock recovery

To verify clock recovery, use the show recovered-clock command.

Router# show recovered-clock sublsot 0/3/0

Recovered clock status for subslot 0/3/0

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

Clock    Mode         Port CEM  Status     Frequency Offset(ppb)

1        ADAPTIVE     0    1    HOLDOVER   0       

Router# show recovered-clock 

Recovered clock status for subslot 3/0

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

Clock    Mode         Port CEM  Status     Frequency Offset(ppb)

1        ADAPTIVE     0    1    ACQUIRING  -694 

Show Commands for CEM

You can use the command show controller cem <forward interface instance> to verify the CEM parameter information. The following example provides a sample output for the command.

Ouput of show controller cem forward interface instance command

RP/0/0/CPU0:Router# show controllers cem 0/4/1/0:0

Interface                : CEM0/4/1/0:0

Admin state              : Up

Driver link state        : Up

Port bandwidth(kbps)     : 1984

Dejitter buffer          : 16

Payload size             : 248

Dummy mode               : last-frame

Dummy pattern            : 0xff

Idle pattern             : 0xff

Signalling               : No CAS

RTP                      : Enabled

Ingress packets          : 1638960097, Ingress packets drop     : 0

Egress packets           : 1207954294, Egress packets drop      : 287140468

Missing packets          : 160475876, Reordered packets        : 50092

Malformed packets        : 73, Misorder drops           : 7

Jitter buffer underrun   : 28, Error seconds            : 79673

Severely error seconds   : 25721, Unavailable seconds      : 160361

Failure counts           : 2

Configuration Examples for CEM

This section contains the following examples:

•Circuit Emulation Interface Configuration: Examples

–Channelized Sonet / SDH Configurations and CEM Interface Creation

–SAToP CEM interface creation on T3 / E3 on Cisco 2-Port Channelized T3/E3 Circuit Emulation and Channelized ATM SPA

–SAToP CEM interface creation on T1 / E1 on Cisco 2-Port Channelized T3/E3 Circuit Emulation and Channelized ATM SPA

–CESoPSN CEM interface creation on T1/E1 on Cisco 2-Port Channelized T3/E3 Circuit Emulation and Channelized ATM SPA

–SAToP CEM interface creation on T1 / E1 on Cisco 24-Port Channelized T1/E1 Circuit Emulation and Channelized ATM SPA

–CESoPSN CEM interface creation on T1 / E1 on Cisco 24-Port Channelized T1/E1 Circuit Emulation and Channelized ATM SPA

•Clock Recovery : Example

–Adaptive Clock Recovery Configuration:

Circuit Emulation Interface Configuration: Examples

The following example shows a sample CEM interface configuration on the Cisco 1-port Channelized OC3/STM-1 SPA.

Channelized Sonet / SDH Configurations and CEM Interface Creation

Sonet - T1 Channelization and CEM Interface Creation

hw-module subslot  <loc> cardtype sonet

controller SONET 0/0/1/0

 sts 1

  mode vt15-t1

sts 2

  mode vt15-t1

sts 3

  mode vt15-t1

commit

In case of structure agnostic cem interface:

controller T1 0/0/1/0/1/4/1

 cem-group unframed

In case of structure aware cem interface:

controller T1 0/0/1/0/1/5/1

 cem-group framed 0 timeslots 1

 cem-group framed 1 timeslots 2-3

 cem-group framed 2 timeslots 4-6

 cem-group framed 3 timeslots 7-10

 cem-group framed 4 timeslots 11-15

 cem-group framed 5 timeslots 16-21

 cem-group framed 6 timeslots 22-24 

SDH - T1 Channelization and CEM Interface Creation

hw-module subslot  <loc> cardtype sdh

controller SONET0/0/2/0

 au 1

  mode c11-t1

 au 2

  mode c11-t1

 au 3

  mode c11-t1

commit

In case of structure agnostic cem interface:

controller T1 0/0/2/0/1/1/4

 cem-group unframed

In case of structure aware cem interface:

controller T1 0/0/2/0/1/7/1

 cem-group framed 0 timeslots 1

 cem-group framed 1 timeslots 2-3

 cem-group framed 2 timeslots 4-6

 cem-group framed 3 timeslots 7-10

 cem-group framed 4 timeslots 11-15

 cem-group framed 5 timeslots 16-21

 cem-group framed 6 timeslots 22-24 

SDH - E1 Channelization and CEM Interface Creation

hw-module subslot  <loc> cardtype sdh

controller SONET 0/0/2/0

 au 1

  mode tug3

  width 3

  tug3 1

   mode c12-e1

tug3 2

   mode c12-e1

 tug3 3

   mode c12-e1

commit

In case of structure agnostic cem interface:

controller E1 0/0/2/0/1/1/1/1

 cem-group unframed

In case of structure aware cem interface:

controller E1 0/0/2/0/1/1/7/1

 cem-group framed 0 timeslots 1

 cem-group framed 1 timeslots 2-3

 cem-group framed 2 timeslots 4-6

 cem-group framed 3 timeslots 7-10

 cem-group framed 4 timeslots 11-15

 cem-group framed 5 timeslots 16-21

 cem-group framed 6 timeslots 22-31 

CEM Interface Configuration

RP/0/RSP0/CPU0:CEOP-01#show runn interface cem 0/0/2/0/1/1/1/1:1

interface CEM0/0/2/0/1/1/1/1:1

 l2transport

 !

CEM Interface Config Options :

RP/0/RSP0/CPU0:CEOP-01(config)#interface cem 0/0/2/0/1/1/1/1:1

RP/0/RSP0/CPU0:CEOP-01(config-if)#cem ?

  class-attach  Attach a CEM class to this interface

  clock         Configure clocks on this CEM interface

  dejitter      Configure dejitter buffer

  dummy         Configure dummy frame parameters

  idle          Configure idle frame parameters

  payload       Configure payload size of CEM frames 

SAToP CEM interface creation on T3 / E3 on Cisco 2-Port Channelized T3/E3 Circuit Emulation and Channelized ATM SPA

RP/0/0/CPU0:router(config)#controller t3 0/4/2/0

RP/0/0/CPU0:router(config-t3)#cem-group ?

  unframed  clear channel carrying CEM

RP/0/0/CPU0:router(config-t3)#cem-group unframed

RP/0/0/CPU0:router(config-t3)#commit

RP/0/0/CPU0:router(config-t3)#

SAToP CEM interface creation on T1 / E1 on Cisco 2-Port Channelized T3/E3 Circuit Emulation and Channelized ATM SPA

RP/0/0/CPU0:router(config)#controller t3 0/4/2/0

RP/0/0/CPU0:router(config-t3)#mode ?

  atm     clear channel carrying atm

  e1      channelize into 21 E1s

  serial  clear channel carrying hdlc like payload

  t1      channelized into 28 T1s

RP/0/0/CPU0:router(config-t3)#mode e1

RP/0/0/CPU0:router(config-t3)#commit

RP/0/0/CPU0:router(config)#controller e1 0/4/2/0/1

RP/0/0/CPU0:router(config-e1)#cem-group ?

  framed    Configure a framed CEM interface on T1/E1

  unframed  Configure a unframed CEM interface on T1/E1

RP/0/0/CPU0:router(config-e1)#cem-group unframed ?

  <cr>

RP/0/0/CPU0:router(config-e1)#cem-group unframed

RP/0/0/CPU0:router(config-e1)#commit

CESoPSN CEM interface creation on T1/E1 on Cisco 2-Port Channelized T3/E3 Circuit Emulation and Channelized ATM SPA

RP/0/0/CPU0:router(config)#controller t3 0/4/2/1

RP/0/0/CPU0:router(config-t3)#mode ?

  atm     clear channel carrying atm

  e1      channelize into 21 E1s

  serial  clear channel carrying hdlc like payload

  t1      channelized into 28 T1s

RP/0/0/CPU0:router(config-t3)#mode t1

RP/0/0/CPU0:router(config-t3)#commit

RP/0/0/CPU0:router(config)#controller t1 0/4/2/1/1

RP/0/0/CPU0:router(config-t1)#cem-group ?

  framed    Configure a framed CEM interface on T1/E1

  unframed  Configure a unframed CEM interface on T1/E1

RP/0/0/CPU0:router(config-t1)#cem-group framed ?

  <0-23>  CEM group number

RP/0/0/CPU0:router(config-t1)#cem-group framed 0 ?

  timeslots  List of timeslots in the CEM group

RP/0/0/CPU0:router(config-t1)#cem-group framed 0 timeslots ?

  WORD  timeslot string seprated by (:) or (-) from 1 to 24. (:) indicates individual 
timeslot and (-) represent range

RP/0/0/CPU0:router(config-t1)#cem-group framed 0 timeslots 1:23

RP/0/0/CPU0:router(config-t1)#commit

SAToP CEM interface creation on T1 / E1 on Cisco 24-Port Channelized T1/E1 Circuit Emulation and Channelized ATM SPA

RP/0/0/CPU0:router(config)#controller e1 0/4/1/2

RP/0/0/CPU0:router(config-e1)#cem-group ?

  framed    Configure a framed CEM interface on T1/E1

  unframed  Configure a unframed CEM interface on T1/E1

RP/0/0/CPU0:router(config-e1)#cem-group unframed ?

  <cr>

RP/0/0/CPU0:router(config-e1)#cem-group unframed

RP/0/0/CPU0:router(config-e1)#commit

CESoPSN CEM interface creation on T1 / E1 on Cisco 24-Port Channelized T1/E1 Circuit Emulation and Channelized ATM SPA

RP/0/0/CPU0:router(config)#controller e1 0/4/1/1

RP/0/0/CPU0:router(config-e1)#cem-group framed ?

  <0-30>  CEM group number

RP/0/0/CPU0:router(config-e1)#cem-group framed 1 ?

  timeslots  List of timeslots in the CEM group

RP/0/0/CPU0:router(config-e1)#cem-group framed 1 timeslots ?

  WORD  timeslot string seprated by (:) or (-) from 1 to 31. (:) indicates individual 
timeslot and (-) represent range

RP/0/0/CPU0:router(config-e1)#cem-group framed 1 timeslots 1:20

RP/0/0/CPU0:router(config-e1)#commit

Clock Recovery : Example

Adaptive Clock Recovery Configuration:

(E1 configurations are similar to T1s given below)

CE1

----

Router (config)#controller t1 0/0/2/0/1/1/4

Router (config-t1)#clock source internal

PE1 (Acts as source of clock, but no specific configuration under CEM Interface is needed 
here)

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

Router (config)#controller t1 0/0/2/0/1/1/4

Router (config-t1)#clock source line

PE2 (On PE node where clock recovery is done):

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

To recover the adaptive clock:

Router(config)# interface cem 0/0/2/0/1/1/4:0

Router(config-if)#cem clock recover <clock-id> adaptive

To apply the recovered clock,

Router (config)#controller t1 0/0/2/0/1/1/4

Router (config-t1)#clock source recovered <clock-id>

CE2

----

Router (config)#controller t1 0/0/2/0/1/1/4

Router (config-t1)#clock source line

Additional References

These sections provide references to related documents.

Related Documents

Standards

MIBs

RFCs

Technical Assistance