Table Of Contents
Configuring AAL2 and AAL5 for the High Performance ATM Advanced Integration Module on the Cisco 2600 Series
Feature Overview
Benefits
Restrictions
Related Documents
Supported Platforms
Supported Standards, MIBs, and RFCs
Prerequisites
Configuration Tasks
Configuring ATM for AAL5
Configuring ATM Interfaces to Support Voice Traffic
Preparing to Configure Voice Dial Peers
Creating a Peer Configuration Table
Configuring Dial Peers
Configuring Cisco-Trunk Permanent Calls
Verifying the Voice Connection
Troubleshooting Tips
Configuring ATM for AAL2
Configuring ATM for AAL2 Voice
Configuring Call Admission Control for AAL2 Voice
Configuring Subcell Multiplexing for AAL2 Voice
Configuring Dial Peers to Support AAL2
Configuring AAL2-Trunk Permanent Calls
Verifying Your Configuration
Troubleshooting Tips
Configuration Examples
Sample Configuration for VoATM at AAL5
Sample Configuration for VoATM at AAL2
Cisco 2600 Configuration at End A
Cisco 2600 Configuration at End B
Command Reference
Glossary
Configuring AAL2 and AAL5 for the High Performance ATM Advanced Integration Module on the Cisco 2600 Series
Feature History
Release
|
Modification
|
12.2(2)XA
|
The High Performance ATM Advanced Integration Module was introduced for the Cisco 2600 series.
|
This feature module describes the software functions of the High Performance ATM Advanced Integration Module (AIM) feature, which allows for ATM Adaptation Layer 2 (AAL2) and ATM Adaptation Layer 5 (AAL5) on the Cisco 2600 series. It includes information on the benefits of the new feature, supported platforms, related documents, and so on.
This document includes the following sections:
•
Feature Overview
•Supported Platforms
•Prerequisites
•Configuration Tasks
•Configuration Examples
•Command Reference
•Glossary
Feature Overview
The High Performance ATM AIM offers a cost-effective solution for supporting low-speed ATM WAN connections on the Cisco 2600 family of products. This feature enables the Cisco 2600 series to carry voice and data traffic over ATM networks using AAL2 and AAL5 without a dedicated ATM network module. AAL2 and AAL5 are the most bandwidth-efficient standards-based trunking methods for transporting compressed voice, voice-band data, circuit-mode data, and frame-mode data over ATM infrastructures. This feature provides a cost-effective, low-density ATM T1 or E1 solution for the Cisco 2600 series.
The High Performance ATM AIM helps service providers take advantage of the inherent quality of service (QoS) features of ATM multiservice applications. Transparent LAN services allow for the connection to separate sites at native LAN speeds, without requiring that the end user be familiar with ATM protocols. Frame Relay network expansion allows enterprise customers to take advantage of ATM's faster transmission speeds by leveraging core ATM switches linked to Frame Relay switches at the edge.
The High Performance ATM AIM is installed into an internal AIM slot. All Cisco 2600 routers support one internal AIM slot that connects to both the Cisco 2600's main system bus and a secondary time-division multiplexing (TDM) bus running between the WAN interface card (WIC) slots and network module slot.
Cisco 2600 routers have two WIC slots. When a High Performance ATM AIM is installed in a Cisco 2600 series router that has one 2-port T1/E1 Multiflex Voice/WAN (VWIC) in a WIC slot, the AIM card allows the router to provide a maximum of two separate ATM WAN interfaces at a DS1 or E1 rate. With a second 2-port VWIC, four separate ATM WAN interfaces are available.
To provide voice over ATM, the Cisco 2600 must have voice port capabilities provided by a digital packet voice trunk network module with a T1/E1 Multiflex VWIC. When also equipped with a High Performance ATM AIM, the router terminates up to 60 voice calls over T1 or E1 using AAL2.
Figure 1 Cisco 2600 Router with High Performance ATM AIM
Benefits
The High Performance ATM AIM provides the following improvements to the Cisco 2600 series' capabilities:
•Cisco 2600 series access to AAL2 and AAL5 capabilities across the WAN
•Cost-effective ATM WAN solution without purchasing an ATM WIC or additional network module
•Increased QoS capabilities
•Standards-based transport of voice over ATM
•Bandwidth-efficiency
•Robust architecture
•Signaling transparency
•Channel-associated signaling (CAS) and common channel signaling (CCS) support
Restrictions
•The number of virtual path identifier (VPI) and virtual channel identifier (VCI) bits must equal 13 bits. The VPI default is five bits with a range of 0 to 31 bits; the VCI default is eight bits with a range of 1 to 256 bits.
•For variable bit rate real time VBR (RT) traffic shaping, the maximum burst size (MBS) is 255 cells.
•Subcell multiplexing is defaulted and not configurable.
•AAL2 supports a permanent virtual circuit (PVC); AAL5 supports PVC and a switched virtual circuit (SVC).
•If all of the 60 channels for transparent common-channel switching (TCCS) and transparent channel-associated signaling (TCAS) over AAL2 are configured, you cannot save the configuration into NVRAM. The configuration must be compressed to save it to the start up.
•The number of AAL2 VCs is limited to 16. Each VC supports up to 255 subchannels, and each subchannel can be used for voice port.
Related Documents
•Cisco IOS Voice, Video, and Fax Configuration Guide, Release 12.2
•Cisco IOS Voice, Video, and Fax Command Reference, Release 12.2
•Cisco IOS Wide-Area Networking Configuration Guide, Release 12.2
•Cisco IOS Wide-Area Networking Command Reference, Release 12.2
Supported Platforms
Cisco 2600 series
Supported Standards, MIBs, and RFCs
Standards
No new or modified standards are supported by this feature.
MIBs
No new or modified MIBs are supported by this feature. The Chassis MIB has been modified to support the High Performance ATM AIM.
For descriptions of supported MIBs and how to use MIBs, seethe Cisco web site on CCO at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.
RFCs
No new or modified RFCs are supported by this feature.
Prerequisites
Before you can configure your router to use the High Performance ATM AIM, complete these tasks:
•Ensure that you have 64 MB RAM and 16 MB Flash memory.
•For Voice over IP, ensure that your Cisco 2600 has a digital T1 or E1 packet voice trunk network module with a T1/E1 multiflex Voice/WAN Interface Card and the required number of digital signal processor (DSP) modules for your configuration. For more information about DSP modules, refer to Connecting Voice Network Modules in the Cisco Network Modules Hardware Installation Guide. Note that the Cisco 2600 series routers must have at least one 1- and 2-Port T1/E1 Multiflex Voice/WAN Interface Card slot.
•Establish a working ATM network. For more information about configuring ATM, refer to the
Cisco IOS Wide-Area Networking Configuration Guide, Release 12.2.
•Complete your company's dial plan.
•Establish a working telephony based on your company's dial plan.
•Integrate your dial plan and telephony network into your existing ATM network topology.
•Contact your PBX vendor for instructions about how to reconfigure the appropriate PBX interfaces.
After you have analyzed your dial plan and decided how to integrate it into your existing ATM network, you are ready to configure your network devices to support the High Performance ATM AIM.
Configuration Tasks
Software configuration for a Cisco 2600 series router with the High Performance ATM AIM feature involves:
•Configuring ATM for AAL5
–Configuring ATM Interfaces to Support Voice Traffic
–Preparing to Configure Voice Dial Peers
–Creating a Peer Configuration Table
–Configuring Dial Peers
–Configuring Cisco-Trunk Permanent Calls
•Configuring ATM for AAL2
–Configuring ATM for AAL2 Voice
–Configuring Call Admission Control for AAL2 Voice (optional)
–Configuring Subcell Multiplexing for AAL2 Voice
–Configuring Dial Peers to Support AAL2
–Configuring AAL2-Trunk Permanent Calls (optional)
Configuring ATM for AAL5
Note The Voice over ATM (VoATM) configuration must be performed on the routers on both sides of the voice connection.
Configuring the Cisco 2600 series to support VoATM for AAL5 encapsulation involves the following:
•Configuring ATM Interfaces to Support Voice Traffic
•Preparing to Configure Voice Dial Peers
•Creating a Peer Configuration Table
•Configuring Dial Peers
•Configuring Cisco-Trunk Permanent Calls
Configuring ATM Interfaces to Support Voice Traffic
This section describes the preliminary ATM configuration tasks necessary to support VoATM.
Note The VoATM configuration must be performed on the routers on both sides of the voice connection.
To configure the Cisco 2600 series to support VoATM, use the following commands beginning in global configuration mode:
| |
Command
|
Purpose
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Step 1
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Router(config)# interface ATMslot/port
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Enters ATM interface configuration mode.
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Step 2
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Router(config-if)# pvc [name] vpi/vci
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Creates an ATM PVC for voice traffic and enter virtual circuit configuration mode.
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Step 3
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Router(config-if-atm-pvc)# encapsulation aal5mux
voice
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Sets the encapsulation of the PVC to support voice traffic.
Note To configure a PVC to support data traffic, use aal5snap encapsulation.
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Step 4
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Router(config-if-atm-pvc)# vbr-rt peak-rate
average-rate [burst]
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Configures the peak rate, average rate, and the burst cell size to perform traffic shaping between voice and data PVCs. By using the vbr-rt command, you can configure the variable bit-rate for real-time networks, such as for voice networks.
Traffic shaping is necessary, so that the carrier does not discard the incoming calls from the router. To configure voice and data traffic shaping, you must configure the peak, average, and burst options for voice traffic. Configure the burst value if the PVC will be carrying bursty traffic. The peak, average, and burst values are needed so the PVC can effectively handle the bandwidth for the number of voice calls. To calculate the minimum peak, average, and burst values for the number of voice calls, use the following calculations:
•Peak value: (2 x the maximum number of calls) x 16 kb
The peak value equals the Peak Information Rate (PIR).
•Average value: (1 x the maximum number of calls) x 16 kb
The average value equals the Average Information Rate (AIR). This correlates to the carrier's sustained cell rate.
•Burst value: (4 x the maximum number of calls)
The burst value is the burst size in cells.
Note When you configure data PVCs that will be traffic shaped with voice PVCs, use the aal5snap encapsulation and calculate the overhead as 1.13 times the voice rate.
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Step 5
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Router(config-if-atm-pvc)# exit
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Exits ATM virtual circuit configuration mode.
The only commands in ATM virtual circuit configuration mode used for ATM voice PVCs are encapsulation aal5mux voice, vbr-rt, and ilmi.
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Step 6
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Router(config-if)# pvc [name] vpi/vci
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Creates an ATM PVC for data traffic and enters virtual circuit configuration mode.
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Step 7
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Router(config-if-atm-pvc)# encapsulation aal5snap
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Sets the encapsulation of the PVC to support ATM data traffic. In ATM PVC configuration mode, configure either the ubr, ubr+, or the vbr-nrt traffic shaping commands for the data PVC as appropriate.
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Step 8
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Router(config-if-atm-pvc)# exit
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Exits ATM virtual circuit configuration mode. Repeat Steps 6 and 7 for each data PVC configured.
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Step 9
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Exits interface configuration mode.
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Step 10
|
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Exits global configuration mode.
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Step 11
|
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Verifies the ATM PVC configuration.
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Note When verifying your ATM PVC connectivity, note that you cannot issue the ping command over a voice PVC because the command applies to data only. If you have data and voice PVCs set to the same destination, you can issue the ping command over the data PVC.
Preparing to Configure Voice Dial Peers
After you have analyzed your dial plan and decided how to integrate it into your existing network, you are ready to configure your network devices to support VoATM. The actual configuration procedure depends on the topology of your voice network.
Timesaver If possible, you might want to configure the ATM dial peers in a back-to-back configuration before separating them across the ATM network. Using a back-to-back configuration, you can test your VoATM and dial-peer configuration to see if you can successfully make a voice connection. Then, when you place both peers on the network, if you cannot make a voice connection, you can isolate the cause as a network problem.
Creating a Peer Configuration Table
There is specific information relative to each dial peer that you must identify before you can configure VoATM. One way to do this is to create a peer configuration table.
Figure 2 shows a diagram of a small voice network in which Router 1, with ATM virtual circuit 20, connects a small sales branch office to the main office through Router 2. There are only two devices in the sales branch office that need to be established as dial peers: a basic telephone and a fax machine. Router 2, with an ATM virtual circuit of 40, is the primary gateway to the main office; as such, it needs to be connected to the company's PBX. There are three basic telephones connected to the PBX that need to be established as dial peers in the main office.
Table 1 shows the peer configuration table for the example illustrated in Figure 2.
Figure 2 Sample VoATM Network
Table 1 Peer Configuration Table for Sample VoATM Network
Dial Peer
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Extension
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Prefix
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Dest-Pattern
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Type
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Voice Port
|
Session Target
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Router 1
|
|
|
|
|
|
|
1
|
61111
|
|
+13101161111
|
POTS
|
2/0/0
|
|
2
|
62222
|
|
+13101162222
|
POTS
|
2/0/1
|
|
10
|
|
|
+1310117....
|
VoATM
|
|
S2 20
|
Router 2
|
|
|
|
|
|
|
11
|
|
|
+1310116....
|
VoATM
|
|
S2 40
|
3
|
73333
|
7
|
+1310117....
|
POTS
|
2/1/0
|
|
4
|
74444
|
7
|
+1310117....
|
POTS
|
2/1/0
|
|
5
|
75555
|
7
|
+1310117....
|
POTS
|
2/1/0
|
|
The dial plan shown in lists a simple dial-peer configuration table with no special configuration for how you forward or play out excess digits. For more information on other options for designing your dial plan and configuring your dial peers to connect with PBXs, see the Cisco IOS Voice, Video, and Fax Configuration Guide, Release 12.2.
Configuring Dial Peers
Dial peers describe the entities to and from which a call leg is established. Dial-peer configuration tasks define the address or set of addresses serviced by that dial peer and the call parameters required to establish a call leg to and from that dial peer.
Two different kinds of dial peers are used for this procedure:
•Plain old telephone service (POTS)—Dial peer connecting a traditional telephony network. POTS dial peers point to a particular voice port on a voice-network device.
•VoATM—Dial peer connecting an ATM WAN backbone. VoATM dial peers point to specific voice-network devices.
POTS dial peers associate a telephone number with a particular voice port, so that incoming calls for that telephone number can be received. VoATM dial peers point to specific voice-network devices (by associating destination telephone numbers with a specific ATM virtual circuit), so that outgoing calls can be placed. Both POTS and VoATM dial peers are required if you want to send and receive calls using VoATM.
Establishing two-way communication with VoATM requires establishing a specific voice connection between two defined endpoints. As shown in Figure 3, for outgoing calls (from the perspective of POTS dial peer 1), the POTS dial peer establishes the source (the originating telephone number and voice port) of the call. The VoATM dial peer establishes the destination by associating the destination phone number with a specific ATM virtual circuit.
Figure 3 Calls from the Perspective of Router No. 1
In the example, the destination pattern string14085554000 maps to a U.S. phone number 555-4000, with the digit 1 plus the area code (408) preceding the number. When configuring the destination pattern, set the dial string to match the local dial conventions.
To complete the two-way communications loop, configure VoATM dial peer 2 as shown in Figure 4.
Figure 4 Calls from the Perspective of Router No. 2
The only exception is when both POTS dial peers are connected to the same router, as shown in Figure 5. In this circumstance, because both dial peers share the same destination IP address, you do not need to configure a VoATM dial peer.
Figure 5 Communication Between Dial Peers Sharing the Same Router
When configuring dial peers, you need to understand the relationship between the destination pattern and the session target. The destination pattern represents the pattern for the device at the voice connection endpoint, such as a telephone or a PBX. The session target represents the serial port on the peer router at the other end of the ATM connection. Figure 6 and Figure 7 show the relationship between the destination pattern and the session target, as seen from the perspective of both routers in a VoATM configuration.
Figure 6 Relationship Between the Destination Pattern and Session Target from the Perspective of Router No.1
Figure 7 Relationship Between the Destination Pattern and Session Target from the Perspective of Router No.2
Configuring POTS Dial Peers
To configure a POTS dial peer, identify the peer (by assigning it a unique tag number), define its telephone number, and associate it with a voice port through which calls can be established. Under most circumstances, the default values for the remaining dial-peer configuration commands are sufficient to establish connections.
To configure POTS peers, use the following commands beginning in global configuration mode:
| |
Command
|
Purpose
|
Step 1
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Router(config)# dial-peer voice tag pots
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Defines a POTS dial peer and enter dial-peer configuration mode.
Note All subsequent commands that you enter in dial-peer voice mode before you exit apply to this dial peer.
The tag value identifies the dial peer and must be unique on the router. Do not duplicate a specific tag number.
|
Step 2
|
Router(config-dial-peer)# destination-pattern string
|
Configures the dial peer's destination pattern.
The string is a series of digits that specify the E.164 or private dialing plan telephone number. Valid entries are the digits 0 through 9 and the letters A through D. You can enter the following special characters in the string:
•The star character (*) and the pound sign (#) that appear on standard touch-tone dial pads can be used in any dial string. However, do not use these characters as leading characters in a string (for example, *650).
•The period (.) can be entered any time, and is used as a wildcard character.
•The comma (,) can be used only in prefixes, and is used to insert a one-second pause or a delay.
•The timer (T) character can be used to configure variable-length dial plans.
|
Step 3
|
Router(config-dial-peer)# port slot/port/subunit
|
Associates this POTS dial peer with a specific logical dial interface. Enters the slot/port/subunit number of the voice port connected to the POTS dial peer.
|
Step 4
|
Router(config-dial-peer)# preference value
|
(Optional) Configures a preference for the POTS dial peer. The value is a number from 0 to 10 where the lower the number, the higher the preference. If POTS and voice-network (VoATM) peers are mixed in the same hunt group, POTS dial peers are searched first, even if a voice-network peer has a higher preference number.
|
Step 5
|
Router(config-dial-peer)# forward-digits {num-digit
| all | extra}
Router(config-dialpeer)# default forward-digits
Router(config-dialpeer)# no forward-digits
|
(Optional) If using the forward-digits feature, configures the digit-forwarding method. The range for the number of digits forwarded (num-digit) is 0 to 32.
In the default condition, dialed digits not matching the destination pattern are forwarded.
Note The no state is not the default state.
|
Step 6
|
Router(config-dial-peer)# prefix string
|
(Optional) If the forward digits feature was not configured in the last step, assigns the dialed digits prefix for the dial peer.
|
Step 7
|
Router(config-dial-peer)# exit
|
Exits dial-peer configuration mode.
|
To configure additional POTS dial peers, repeat the previous steps.
Configuring VoATM Dial Peers
To configure a VoATM dial peer, you need to uniquely identify the peer by assigning it a unique tag number and define the outgoing serial port number and the virtual circuit number.
To configure VoATM dial peers, use the following commands beginning in global configuration mode:
| |
Command
|
Purpose
|
Step 1
|
Router(config)# dial-peer voice tag voatm
|
Defines a VoATM dial peer for VoATM and enter dial-peer configuration mode.
The tag value identifies the dial peer and must be unique on the router. Do not duplicate a specific tag number.
|
Step 2
|
Router(config-dial-peer)# destination-pattern string
|
Configures the dial peer's destination pattern. The same restrictions for the string listed in the POTS dial-peer configuration also apply to the VoATM destination pattern.
|
Step 3
|
Router(config-dial-peer)# session target ATMx/y pvc
[name] | [vpi/]vci]
|
Configures the ATM session target for the dial peer.
On the Cisco 2600, if you specify a vpi/vci combination, the valid values depend on the network module installed.
If you have the Multiport T1/E1 ATM network module with IMA installed, the valid range for vpi is 0-15, and the valid range for vci is 1-255.
If you have the OC3 ATM Network Module installed, the valid range for vpi is 0-15, and the valid range for vci is 1-1023.
|
Step 4
|
Router(config-dial-peer)# preference value
|
(Optional) Configures a preference for the VoATM dial peer. The value is a number from 0 to 10 where the lower the number, the higher the preference.
|
Step 5
|
Router(config-dial-peer)# codec type [bytes bytes]
|
Specifies the voice coder rate of speech and payload size for the dial peer. The default dial peer codec is g729r8.
Specifying the payload size by entering the bytes value is optional. Each codec type defaults to a different payload size if you do not specify a value. To obtain a list of the default payload sizes, enter the codec command and the bytes option followed by a question mark (?).
|
Step 6
|
Router(config-dial-peer)# dtmf-relay
|
(Optional) If the codec type is a low bit-rate codec such as g729 or g723, specifies support for DTMF relay to improve end-to-end transport of DTMF tones. DTMF tones do not always propagate reliably with low bit-rate codecs.
DTMF relay is disabled by default.
|
Step 7
|
Router(config-dial-peer)# signal-type {cas | cept |
ext-signal | transparent}
|
(Optional) Defines the type of the ABCD signaling packets that are generated by the voice port and sent to the data network. The signal type must be configured to the same setting at both ends of the permanent voice call.
Enter cas to support CAS. Enter cept to support the European CEPT standard (related to MEL CAS).
Enter ext-signal to indicate that ABCD signaling packets should not be sent, for configurations where the line signaling information is carried externally to the voice port.
Enter transparent (for digital T1/E1 interfaces) to read the ABCD signaling bits directly from the T1/E1 interface without interpretation and to pass them transparently to the data network. (This is also known as transparent FRF.11 signaling.)
|
Step 8
|
Router(config-dial-peer)# no vad
|
(Optional) Disables voice activity detection (VAD) on the dial peer. This command is enabled by default.
|
Step 9
|
Router(config-dial-peer)# sequence-numbers
|
(Optional) Enables the voice sequence number if required for your configuration. This command is disabled by default.
|
Step 10
|
Router(config-dial-peer)# preference value
|
(Optional) Configures a preference for the VoFR dial peer. The value is a number from 0 to 10 where the lower the number, the higher the preference in hunt groups.
|
Step 11
|
Router(config-dial-peer)# session protocol
cisco-switched
|
(Optional) Configures the session protocol to support Cisco-trunk permanent (private line) trunk calls.
The cisco-switched option is the default setting, and entering this command is not required.
If you do not want the dial peer to support Cisco-trunk permanent (private line) trunk calls, enter no session protocol cisco-switched.
|
Step 12
|
Router(config-dial-peer)# fax rate {2400 | 4800 | 7200 |
9600 | 14400 | disable | voice}
|
(Optional) Configures the transmission speed (in bps) at which a fax will be sent to the dial peer.
The default is voice, which specifies the highest possible transmission speed allowed by the voice rate.
|
Step 13
|
Router(config-dial-peer)# exit
|
Exits dial-peer configuration mode.
|
To configure additional VoATM dial peers, repeat the previous steps.
Configuring Dial Peer Hunting
After you have configured dial peers, you can configure how the router performs dial peer hunting functions. To configure the dial peer hunting behavior on the router, perform the following steps beginning in global configuration mode:
| |
Command
|
Purpose
|
Step 1
|
Router(config)# dial-peer hunt hunt-order-number
|
Specifies the hunt selection order for dial peers.
|
Step 2
|
Router(config)# dial-peer terminator character
|
(Optional) Designates a special character to be used as a terminator for variable length dialed numbers.
|
If using dial peer hunting, there may be situations when you want to disable dial-peer hunting on a specific dial peer. To disable dial-peer hunting on a dial peer, use the following commands beginning in global configuration mode:
| |
Command
|
Purpose
|
Step 1
|
Router(config)# dial-peer voice tag {pots | voatm}
|
Enters dial-peer configuration mode for the specified dial peer.
|
Step 2
|
Router(config-dial-peer)# huntstop
|
Disables dial-peer hunting on the dial peer. Once you enter this command, no further hunting is allowed if a call fails on the specified dial peer.
|
Step 3
|
Router(config-dial-peer)# exit
|
Exits dial-peer configuration mode.
|
To reenable dial-peer hunting on a dial peer, enter the no huntstop command.
Configuring Cisco-Trunk Permanent Calls
To configure Cisco-trunk permanent calls on a Cisco 2600 series router for VoATM, use the following commands from global configuration mode:
| |
Command
|
Purpose
|
Step 1
|
For Cisco 2600 series analog voice ports:
Router(config)# voice-port slot/subunit/port
For Cisco 2600 series digital voice ports:
Router(config)# voice-port slot/port:ds0-group
|
Identifies the voice port you want to configure and enter voice-port configuration mode.
|
Step 2
|
Router(config-voiceport)# connection trunk
destination-string [answer-mode]
|
Configures the trunk connection and specify the telephone number in the destination-string.
When configuring Cisco-trunk permanent calls, one side must be the call initiator (master) and the other side is normally the call answerer (slave). By default, the voice port operates in master mode. Enter the answer-mode keyword to specify that the voice port operates in slave mode.
|
Step 3
|
Router(config-voiceport)# shutdown
|
Shuts down the voice port.
|
Step 4
|
Router(config-voiceport)# no shutdown
|
Reactivates the voice port to enable the trunk connection to take effect.
|
Step 5
|
Router(config-voiceport)# exit
|
Exits voice-port configuration mode.
|
Note Every time you enter the connection trunk or no connection trunk command, you must toggle the voice port (by entering shutdown, then no shutdown) for the changes to take effect.
Verifying the Voice Connection
Verify that the voice connection is working by doing the following:
•Pick up the handset on a telephone connected to the configuration and verify that you can get a dial tone.
•Make a call from the local telephone to a configured dial peer and verify that the call attempt is successful.
You can check the validity of your dial-peer and voice-port configuration by performing the following tasks:
•If you have relatively few dial peers configured, you can use the show dial-peer voice command to verify that the data configured is correct.
•To show the status of the voice ports, use the show voice port command.
•To show the call status for all voice ports, use the show voice call command.
•To show the current status of all DSP voice channels, use the show voice dsp command.
Troubleshooting Tips
If you are having trouble connecting a call and you suspect the problem is associated with the dial-peer configuration, you can try to resolve the problem by performing the following tasks:
•Use the show dial-peer voice command on the local and remote routers to verify that the data is configured correctly on both.
•Use the show interface command to verify that the ATM interface is up.
•Make sure the voice ports, serial ports, and controllers are set to no shutdown.
Configuring ATM for AAL2
To configure the High Performance ATM AIM for AAL2, complete the following tasks, as required:
•Configuring ATM for AAL2 Voice
•Configuring Call Admission Control for AAL2 Voice (optional)
•Configuring Subcell Multiplexing for AAL2 Voice
•Configuring Dial Peers to Support AAL2
•Configuring AAL2-Trunk Permanent Calls (optional)
Note ATM defaults to Interim Local Management Interface (ILMI). If your carrier is using Local Management Interface (LMI), be sure to configure LMI support on the router.
Configuring ATM for AAL2 Voice
This section describes the ATM configuration tasks necessary to support VoATM using AAL2. The commands and procedures in this section are specific to the Cisco 2600 series.
Note If any DS0 groups (CAS groups), channel groups, or clear channels are configured on the T1/E1 controller at the slot/port, you must remove them before configuring VoATM. Because ATM uses all of the DS0 time slots on the controller, the ATM configuration cannot take place if any DS0s on the controller at the slot/port are used by other applications.
You must perform the VoATM configuration on the Cisco 2600 series at both ends of the ATM link.
To configure a Cisco 2600 series router to support VoATM on a T1/E1 trunk, complete the following steps, beginning in global configuration mode:
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Command
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Purpose
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Step 1
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Router(config)# network-clock-participate slot
slot
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Enables the Cisco 2600 series router to receive clock signals from the High Performance ATM AIM by entering the slot number on the router.
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Step 2
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Router(config)# network-clock-select priority
{t1 | e1} slot/port
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Names the 1- and 2-Port T1/E1 Multiflex Voice/WAN Interface Card as the resource that will provide timing for the network clock. Specify the selection priority for the clock.
Use the no form of this command to cancel the selection.
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Step 3
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Router(config)# controller {t1 | e1} slot/port
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Selects the T1 or E1 controller slot or port. On the Cisco 2600 router, ATM is supported by a slot and port.
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Step 4
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Router(config-controller)# clock-source line
primary
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Specifies the primary time-division multiplexing (TDM) source clock as T1 or E1. Use the no form of this command to change or remove the clocking source.
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Step 5
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Router(config-controller)# mode atm aim 0
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Specify that the controller will support ATM encapsulation and create ATM AIM interface 0. The purpose of this command is to create an interface in preparation for Step 8.
When the controller is set to ATM mode, the following takes place:
•Controller framing is automatically set to Extended SuperFrame (ESF) on T1 and to CRC4 on E1.
•The line code is automatically set to B8ZS on T1 and to HDB3 on E1.
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Step 6
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Router(config-controller)# no shutdown
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Makes sure that the controller is activated.
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Step 7
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Router(config-controller)# exit
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Exits controller configuration mode.
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Step 8
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Router(config)# interface atmslot/port
[subinterface-number [multipoint |
point-to-point]]
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Enters interface configuration mode to configure the High Performance ATM AIM slot and port, or an ATM subinterface.
For subinterfaces, the default is multipoint.
Note A subinterface is not generated by default; it must be created explicitly.
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Step 9
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Router(config-if)# pvc [word] {vpi/vci | vci}
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Creates an ATM permanent virtual circuit (PVC) for voice traffic and enter ATM virtual circuit configuration mode. The defaults are as follows:
vpi = 0 to 31 bits
vci = 1 to 255 bits
word = optional PVC identifier (letters only); if you assign a PVC identifier, you can use it to specify this PVC when configuring network dial peers.
Note The ilmi and qsaal options are not supported for AAL2.
The atm vc-per command can be used to change the vci or vpi/vci bit range.
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Step 10
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Router(config-if-atm-vc)# encapsulation aal2
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Sets the encapsulation of the PVC to support AAL2 voice traffic. This automatically creates channel identifiers (CIDs) 1 through 255.
Note The shutdown controller command shuts down the controller and ATM interface. To do a no shut, the no shutdown command must be used.
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Step 11
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Router(config-if-atm-vc)# vbr-rt peak-rate
average-rate [burst]
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Configures the PVC for variable-bit-rate real-time (voice) traffic. Guidelines for setting the peak rate, average rate, and burst size are as follows:
•Peak rate: If it does not exceed your carrier's allowable rate, set to the line rate (for example, 1500 kbps for T1-ATM).
•Average rate: Calculate according to the maximum number of calls the PVC will carry times the bandwidth per call. The following formulas give you the average rate in kbps:
G.711 with 40 or 80 byte sample size—max calls x 85
G.726 with 40 or 80 byte sample size—max calls x 43
G.729 with 30 byte sample size—max calls x 15
G.729 with 20 byte sample size—max calls x 22
G.729 with 10 byte sample size—max calls x 43
If voice activity detection (VAD) is enabled, the bandwidth usage is reduced by as much as 12 percent with the maximum number of calls in progress. With fewer calls in progress, bandwidth savings are less.
•Burst size: Set the burst size as large as possible, and never less than the minimum burst size. Guidelines are as follows:
The minimum burst size is 4 x the number of voice calls.
The maximum burst size is 255 cells.
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Step 12
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Router(config-if-atm-vc)# oam-pvc [manage]
[frequency]
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(Optional) Configures transmission of end-to-end F5 Operation and Maintenance (OAM) loopback cells on a PVC, optionally specify the number of seconds between loopback cells, and optionally enable OAM management of the connection.
The range for frequency is 0 to 600. The default is 10.
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Step 13
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Router(config-if-atm-vc)# oam retry up-count
down-count retry-frequency
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(Optional) Specifies OAM management parameters for verifying connectivity of a PVC connection. This command is supported only if OAM management is enabled.
•The up-count is the number of OAM loopback cell responses received to change the PVC connection to up. The range is 1 to 600; the default is 3.
•The down-count is the number of OAM loopback cell responses not received to change the PVC connection to down. The range is 1 to 600; the default is 5.
•The retry-frequency is the number of seconds between loopback cells sent to verify the down state of a PVC. The range is 1 to 1000; the default is 1.
Note Enter the oam retry command only once. with all of the arguments in the order shown. The first number always specifies up-count; the second down-count, and the third retry-frequency.
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Step 14
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Router(config-if-atm-vc)# end
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Exits configuration mode.
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Step 15
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Verifies the ATM PVC configuration.
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Note When verifying your ATM PVC connectivity, note that you cannot enter the ping command over a voice PVC because the command applies to data only. If you have data and voice PVCs set to the same destination, you can enter the ping command over the data PVC.
Configuring Call Admission Control for AAL2 Voice
This section describes the configuration tasks necessary to configure call admission control (CAC) for AAL2 voice. The commands and procedures in this section are specific to the Cisco 2600 series. CAC is an optional feature.
You can configure a Cisco 2600 router as either a CAC master or a CAC slave. By default, a Cisco 2600 router is a CAC slave. You typically configure a CAC master at one end of an ATM trunk and a CAC slave at the opposite end. A Cisco 2600 series router configured as a master always performs CAC during fax/modem upspeed. A Cisco 2600 series router configured as a slave sends a request for CAC to the CAC master.
To configure a Cisco 2600 series router as a CAC master, complete the following steps beginning in global configuration mode:
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Command
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Purpose
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Step 1
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Router(config)# voice service voatm
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Enters voice-service configuration mode.
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Step 2
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Router(config-voice-service)# session protocol aal2
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Enters voice-service-session configuration mode and specifies AAL2 trunking.
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Step 3
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Router(config-voice-service-session)# cac master
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Configures this Cisco 2600 router as a CAC master.
By default, a Cisco 2600 router is a CAC slave.
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Step 4
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Router(config-voice-service-session)# end
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Exits voice-service-session configuration mode.
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To return a Cisco 2600 series router to its default operation as a CAC slave, complete the following steps beginning in global configuration mode:
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Command
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Purpose
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Step 1
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Router(config)# voice service voatm
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Enters voice-service configuration mode.
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Step 2
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Router(config-voice-service)# session protocol aal2
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Enters voice-service-session configuration mode and specifies AAL2 trunking.
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Step 3
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Router(config-voice-service-session)# no cac master
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Configures this Cisco 2600 as a CAC slave.
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Step 4
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Router(config-voice-service-session)# end
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Exits voice-service configuration mode.
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Configuring Subcell Multiplexing for AAL2 Voice
Subcell multiplexing is always on. It cannot be turned off.
Configuring Dial Peers to Support AAL2
For more information on dial peers and dial-peer configuration, see the Cisco IOS Voice, Video, and Fax Configuration Guide, Release 12.2. To configure a network dial peer for VoATM, complete the following steps, beginning in global configuration mode:
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Command
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Purpose
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Step 1
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Router(config)# dial-peer voice tag voatm
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Defines a Voice-over-ATM dial peer for VoATM and enter dial-peer configuration mode.
The tag identifies the dial peer. Each tag on any one router must be a unique number.
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Step 2
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Router(config-dial-peer)# destination-pattern string
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Configures the dial peer's destination pattern.
The string is a series of digits that specify the E.164 or private dialing plan telephone number. Valid entries are the digits 0 through 9 and the letters A through D. The following special characters can be entered in the string:
•The star (*) and the pound sign (#) can be used in a dial string, but not as leading characters (for example *650 is not permitted).
•The period (.) can be entered as a wildcard digit. Network dial peers typically use wildcards to represent a range of destination telephone numbers (for example, 1408555.... for all numbers in area code 408 with the 555 prefix).
•The comma (,) can be used only in prefixes, and is used to insert a 1-second pause.
•The timer (T) character can be used to configure variable-length dial plans.
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Step 3
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Router(config-dial-peer)# session protocol aal2-trunk
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Configures the session protocol to support AAL2-trunk permanent (private line) trunk calls.
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Step 4
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Router(config-dial-peer)# session target atmslot/port
pvc {word | vpi/vci | vci} cid
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Configures the ATM session target for the dial peer. Be sure to specify atmslot/port as the interface for the PVC.
Use word to identify the PVC if a word name was assigned when the PVC was created in Step 9 of the "Configuring ATM for AAL2 Voice" section.
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Step 5
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Router(config-dial-peer)# codec aal2 profile {itut |
custom} profile-number codec
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Specifies a codec profile for the DSP.
Profile options are itut 1, itut 2, itut 7, custom 100, and custom 110.
The default is itut 1 with codec G.711ulaw.
See the command reference for the codec options available for each AAL2 profile.
Note Use this command instead of the codec (dial-peer) command for AAL2 trunk applications.
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Step 6
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Router(config-dial-peer)# dtmf-relay
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(Optional) If the codec type is a low bit-rate codec such as G.729 or G.723, specifies support for Dual-Tone Multi-Frequency (DTMF) relay to improve end-to-end transport of DTMF tones. DTMF tones do not always propagate reliably with low bit-rate codecs.
DTMF relay is disabled by default.
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Step 7
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Router(config-dial-peer)# signal-type {ext-signal |
transparent}
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(Optional) Defines the type of ABCD signaling packets that are generated by the voice port and sent over the ATM network. The signal type must be configured to the same setting at both ends of the PVC.
Enter ext-signal for common channel signaling (CCS). ABCD signaling packets are not sent.
Enter transparent for nonswitched trunks using channel-associated signaling (CAS). ABCD signaling bits are passed transparently to the ATM network.
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Step 8
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Router(config-dial-peer)# no vad
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(Optional) Disables voice activity detection (VAD) on the dial peer. VAD is enabled by default.
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Step 9
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Router(config-dial-peer)# exit
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Exits from the dial-peer configuration mode.
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Step 10
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To configure additional voice over ATM dial peers, repeat Step 1 through Step 9.
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Configuring AAL2-Trunk Permanent Calls
To configure AAL2-trunk permanent calls on a Cisco 2600 series router, complete the following commands, beginning in global configuration mode:
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Command
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Purpose
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Step 1
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Router(config)# voice-port
{slot|port]:ds0-group
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For the Cisco 2600 series router's digital voice ports, enters voice port configuration mode.
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