Voice over ATM with AAL2 Trunking on Cisco MC3810 Series Concentrators

Note If any DS0 groups (CAS groups), channel groups, or clear channels are configured on T1/E1 controller 0, you must remove them before configuring VoATM. Because ATM uses all of the DS0 timeslots on the controller, the ATM configuration cannot take place if any DS0s on controller 0 are used by other applications.

You must perform the VoATM configuration on the Cisco MC3810 concentrators at both ends of the ATM link.

To configure a Cisco MC3810 series concentrator to support VoATM on a T1/E1 trunk, complete the following steps beginning in global configuration mode:

	Command	Purpose
Step 1	router(config)# controller {t1 | e1} 0	Select the T1 or E1 controller 0. On the Cisco MC3810, ATM is supported only on controller 0.
Step 2	router(config-controller)# mode atm	Specify that the controller will support ATM encapsulation and create ATM interface 0. 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 linecode is automatically set to B8ZS on T1 and to HDB3 on E1.
Step 3	router(config-controller)# no shutdown	Make sure the controller is activated.
Step 4	router(config-controller)# exit	Exit controller configuration mode.
Step 5	router(config)# interface atm0 [subinterface-number [multipoint | point-to-point]]	Enter interface configuration mode to configure ATM interface 0 or an ATM subinterface. For subinterfaces, the default is multipoint.
Step 6	router(config-if)# pvc [word] {vpi/vci | vci}	Create an ATM PVC for voice traffic and enter ATM virtual circuit configuration mode. vpi = 0 to 255 vci = 1 to 1023 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.
Step 7	router(config-if-atm-vc)# encapsulation aal2	Set the encapsulation of the PVC to support AAL2 voice traffic. This automatically creates channel identifiers (CIDs) 1 through 255.
Step 8	router(config-if-atm-vc)# vbr-rt peak-rate average-rate [burst]	Configure 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, 1536 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 the maximum allowed by the carrier.
Step 9	router(config-if-atm-vc)# oam-pvc [manage] [frequency]	(Optional) Configure transmission of end-to-end F5 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.
Step 10	router(config-if-atm-vc)# oam retry up-count down-count retry-frequency	(Optional) Specify 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.
Step 11	router(config-if-atm-vc)# end	Exit configuration mode.
Step 12	router# show atm vc	Verify the ATM PVC configuration.

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.

You can configure a Cisco MC3810 as either a CAC master or a CAC slave. By default, a Cisco MC3810 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 MC3810 configured as a master always performs CAC during fax/modem upspeed. A Cisco MC3810 configured as a slave sends a request for CAC to the CAC master.

To configure a Cisco MC3810 as a CAC master, complete the following steps beginning in global configuration mode:

	Command	Purpose
Step 1	router(config)# voice service voatm	Enters voice-service configuration mode.
Step 2	router(config-voice-service)# session protocol aal2	Enters voice-service-session configuration mode and specifies AAL2 trunking.
Step 3	router(config-voice-service-session)# cac master	Configures this Cisco MC3810 as a CAC master. By default, a Cisco MC3810 is a CAC slave.
Step 4	router(config-voice-service-session)# end	Exits configuration mode.

To return a Cisco MC3810 to its default operation as a CAC slave, complete the following steps beginning in global configuration mode:

	Command	Purpose
Step 1	router(config)# voice service voatm	Enters voice-service configuration mode.
Step 2	router(config-voice-service)# session protocol aal2	Enters voice-service-session configuration mode and specifies AAL2 trunking.
Step 3	router(config-voice-service-session)# no cac master	Configures this Cisco MC3810 as a CAC slave.
Step 4	router(config-voice-service-session)# end	Exits configuration mode.

Syntax Description

This command has no arguments or keywords.

Defaults

The Cisco MC3810 is enabled as a CAC slave.

Command Modes

Voice-service configuration

Command History

Release	Modification
12.1(1)XA	The command was introduced for the Cisco MC3810 series.
12.1(2)T	This command was implemented in the 12.1(2)T release.

Usage Guidelines

You should configure the Cisco MC3810 concentrators at opposite ends of an AAL2 trunk for the opposite CAC operation---master at one end and slave at the other end.

A Cisco MC3810 configured as a master always performs CAC during fax/modem upspeed. A Cisco MC3810 configured as a slave sends a request for CAC to the CAC master.

Examples

The following example configures the CAC operation of a Cisco MC3810 as master:

router(config)# voice service voatm
router(config-voice-service)# session protocol aal2
router(config-voice-service-session)# cac master
 

The following example returns the CAC operation of a Cisco MC3810 to slave:

router(config)# voice service voatm
router(config-voice-service)# session protocol aal2
router(config-voice-service-session)# no cac master

Syntax Description

itut	Specifies the profile-number as an ITU-T type.
atmf	Specifies the profile-number as an ATMF type.
custom	Specifies the profile-number as a custom type.
profile-number	The available profile-number selections depend on the profile type. For ITU-T: 1 = G.711ulaw 2 = G.711ulaw with silence insertion descriptor (sid) 7 = G.711ulaw and G.729ar8 For ATMF: None. ATMF is not supported. For custom: 100 = G.711ulaw and G.726r32 110 = G.711ulaw, G.726r32, and G.729ar8
codec	Enter one codec for the DSP. The possible codec entries depend on the profile-number. The valid entries are as follows: For ITU 1---g711ulaw For ITU 2---g711ulaw For ITU 7---g711ulaw or g729ar8 For custom 100---g711ulaw or g726r32 For custom 110---g711ulaw or g726r32 or g729ar8

Defaults

The default is ITU profile 1 (G.711ulaw).

Command Modes

Dial-peer configuration

Command History

Release	Modification
12.1(1)XA	The command was introduced for the Cisco MC3810 series.
12.1(2)T	This command was implemented in the 12.1(2)T release.

Usage Guidelines

Use this command to configure the DSP to operate with specified a profile type and codec(s).

You must enter the session protocol aal2-trunk command before configuring the codec AAL2 profile.

This command is used instead of the codec (dial-peer) command for AAL2 trunk applications.

Examples

The following example sets the codec AAL2 profile type to ITU and configures a profile-number of 7, enabling codec G.729ar8:

router(config)# dial-peer voice 100 voatm 
router(config-dial-peer)# session protocol aal2-trunk
router(config-dial-peer)# codec aal2-profile itu 7 g729ar8
 

The following example sets the codec AAL2 profile type to custom and configures a profile-number of 100, enabling codec G.726r32:

router(config)# dial-peer voice 200 voatm 
router(config-dial-peer)# session protocol aal2-trunk
router(config-dial-peer)# codec aal2-profile custom 100 g726r32

Related Commands

Command	Description
session protocol (dial-peer)	Establishes a session protocol for calls between the local and remote routers via the packet network.

Note This document only describes encapsulation settings for AAL2 Voice over ATM on the Cisco MC3810 series. For the full syntax of the encapsulation command, refer to the Cisco IOS Wide-Area Networking Command Reference.

Syntax Description

aal-encap

ATM adaptation layer (AAL) and encapsulation type. For AAL2 Voice over ATM the value for aal-encap is aal2.

Defaults

The global default encapsulation is aal5snap.

Command Modes

Virtual circuit (vc) configuration

Command History

Release	Modification
11.3 T	This command was first introduced.
12.0	This command superseded the encapsulation atm command for the Cisco MC3810, and the aal5mux frame and aal5mux voice suboptions appeared.
12.0(7)XK	Support for the aal5mux voice option was added to the Cisco 3600 series routers.
12.1(1)XA	Support for the aal2 option was added to the Cisco MC3810 series concentrators.
12.1(2)T	This command was implemented in the 12.1(2)T release.

Usage Guidelines

Use aal2 encapsulation to dedicate the specified PVC to AAL2 Voice over ATM.

If you specify virtual template parameters after the ATM PVC is configured, you should issue a shutdown command followed by a no shutdown command on the ATM subinterface to restart the interface, causing the newly configured parameters (such as an IP address) to take effect.

Examples

The following example configures a PVC to support AAL2 encapsulation for Voice over ATM on a Cisco MC3810 series concentrator:

router(config-interface-atm)# pvc 20/20
router(config-interface-atm-vc)# encapsulation aal2

Syntax Description

aal2-trunk	AAL2 nonswitched trunk session protocol.
cisco	Cisco session protocol.

Defaults

VoATM trunks use Cisco session protocol.

Command Modes

Dial-peer configuration

Command History

Release	Modification
11.3(1)T	This command was introduced for Cisco 3600 series VoIP peers with the keyword cisco.
12.0(3)XG	The cisco-switched and frf11-trunk keywords were added for VoFR dial peers.
12.1(1)XA	Support was added for VoATM dial peers on the Cisco MC3810 series with the aal2-trunk keyword.
12.1(2)T	This command was implemented in the 12.1(2)T release.

Usage Guidelines

The keyword cisco is only applicable to VoIP on the Cisco 3600 series.

The keyword aal2-trunk is only applicable to VoATM on the Cisco MC3810 series.

Examples

The following example selects AAL2 trunking as the session protocol on a Cisco MC3810 series concentrator:

router(config)# dial-peer voice 10 voatm
router(config-dialpeer)# session protocol aal2-trunk
 

The following example selects Cisco Session Protocol as the session protocol on a Cisco 3600 series router:

router(config)# dial-peer voice 20 voip
router(config-dialpeer)# session protocol cisco

Related Commands

Command	Description
session target	Configures a network-specific address for a dial peer.

Syntax Description

This command has no keywords or arguments.

Defaults

There is no default setting for this command.

Command Modes

Voice-service configuration

Command History

Release	Modification
12.1(1)XA	This command was introduced on the Cisco MC3810 series.
12.1(2)T	This command was implemented in the 12.1(2)T release.

Usage Guidelines

This command applies to VoATM on the MC3810 series.

In the voice-service-session configuration mode for AAL2, you can configure only AAL2 features, such as call admission control and subcell multiplexing.

Examples

The following example shows how to access the voice-service-session configuration mode, beginning in global configuration mode:

router(config)# voice service voatm
router(config-voice-service)# session protocol aal2
router(config-voice-service-session)#

Syntax Description

serial	A serial interface for the dial-peer address.
atm	An ATM interface for the dial-peer address.
interface-number	The interface number for the dial-peer address.
pvc	The specific ATM permanent virtual circuit (PVC) for this dial peer.
word	(Optional) A name to identify the PVC. You can use word to identify the PVC if a word identifier was assigned when the PVC was created.
vpi/vci	ATM network virtual path identifier (VPI) and virtual channel identifier (VCI) of this PVC. On the Cisco MC3810 series the valid range is: for vpi 0 to 255 and for vci 1 to 1023.
vci	ATM network virtual channel identifier (VCI) of this PVC. On the Cisco MC3810 series the valid range is 1 to 1023.
cid	ATM network channel identifier (CID) of this PVC. The valid range is 8 to 255.

Defaults

No network specific address is specified.

Command Modes

Dial-peer configuration

Command History

Release	Modification
11.3(1) T	This command was first introduced.
11.3(1) MA	Support was added for VoFR, VoATM, and VoHDLC dial peers on the Cisco MC3810 series.
12.0(3) XG	The cid option was added. Support was added for VoFR dial peers on the Cisco 2600 and Cisco 3600 series routers.
12.0(4)T	This command was implemented in the 12.0(4)T release.
12.0(7)XK	Support was added for VoATM dial peers on the Cisco 3600 series routers. Support was added for VoIP dial peers on the Cisco MC3810 series. Support for VoHDLC on the Cisco MC3810 series was removed.
12.1(1)XA	Support was added for VoATM dial peers on the Cisco MC3810 series.
12.1(2)T	This command was implemented in the 12.1(2)T release.

Usage Guidelines

Use the session target command to specify a network-specific address or domain name for a dial peer. Whether you select a network-specific address or a domain name depends on the session protocol you select.

You must enter the session protocol aal2-trunk dial-peer configuration command before you can specify a cid for a dial peer.

Examples

The following example configures a session target for Voice over ATM on a Cisco MC3810. The session target is sent to ATM interface 0, and is for a PVC with a VPI/VCI of 1/100.

router(config)# dial-peer voice 12 voatm
router(config-dialpeer)# destination-pattern 1310222....
router(config-dialpeer)# session protocol aal2-trunk
router(config-dialpeer)# session target atm 0 pvc 1/100 10

Related Commands

Command	Description
codec (dial-peer)	Specifies the voice coder rate of speech for a dial peer.
destination-pattern	Specifies either the prefix or the full E.164 telephone number to be used for a dial peer.
dtmf-relay	Enables the DSP to generate FRF.11 Annex A frames for a dial peer.
session protocol (dial-peer)	Establishes a session protocol for calls between the local and the remote routers via the packet network.
signal-type	Sets the signaling type to be used when connecting to a dial peer.

Syntax Description

atmf	Displays ATMF profiles configured on the system.
itut	Displays ATU-T profiles configured on the system.
all	Displays ATU-T, ATMF, and custom AAL2 profiles configured on the system.
custom	Displays custom profiles configured on the system.
profile-number	Specifies the profile number of the AAL2 profile to display. The available choices are as follows: For ITU-T: 1 = G.711ulaw 2 = G.711ulaw with silence insertion descriptor (sid) 7 = G.711ulaw and G.729ar8 For ATMF: None. ATMF is not supported. For custom: 100 = G.711ulaw and G.726r32 110 = G.711ulaw, G.726r32, and G.729ar8

Command Modes

User EXEC

Command History

Release	Modification
12.1(1)XA	This command was introduced on the Cisco MC3810 series.
12.1(2)T	This command was implemented in the 12.1(2)T release.

Usage Guidelines

This command applies to AAL2 VoATM applications on the Cisco MC3810 series.

Use the show aal2 profile EXEC command to display the AAL2 profiles configured in the system.

Examples

The following is sample output from the show aal2 profile command for displaying all of the configured profiles in the system:

router# show aal2 profile all
Printing all the Profiles in the system
 
 
Profile Type: ITUT Profile Number: 1 SID Support: 0
Red enable: 1 Num entries: 1
Coding type: g711ulaw Packet length: 40 UUI min: 0 UUI max: 15
 
Profile Type: ITUT Profile Number: 2 SID Support: 1
Red enable: 1 Num entries: 1
Coding type: g711ulaw Packet length: 40 UUI min: 0 UUI max: 15
 
Profile Type: custom Profile Number: 100 SID Support: 1
Red enable: 1 Num entries: 2
Coding type: g711ulaw Packet length: 40 UUI min: 0 UUI max: 7
Coding type: g726r32 Packet length: 40 UUI min: 8 UUI max: 15
 
Profile Type: ITUT Profile Number: 7 SID Support: 1
Red enable: 1 Num entries: 2
Coding type: g711ulaw Packet length: 40 UUI min: 0 UUI max: 15
Coding type: g729ar8 Packet length: 10 UUI min: 0 UUI max: 15
 
Profile Type: custom Profile Number: 110 SID Support: 1
Red enable: 1 Num entries: 3
Coding type: g711ulaw Packet length: 40 UUI min: 0 UUI max: 7
Coding type: g726r32 Packet length: 40 UUI min: 8 UUI max: 15
Coding type: g729ar8 Packet length: 30 UUI min: 8 UUI max: 15
 

Related Commands

Command	Description
codec aal2-profile	Sets the codec profile for a DSP on a per-call basis.

Syntax Description

This command has no arguments or keywords.

Defaults

Subcell multiplexing is not enabled.

Command Modes

Voice-service configuration

Command History

Release	Modification
12.1(1)XA	The command was introduced for the Cisco MC3810 series.
12.1(2)T	This command was implemented in the 12.1(2)T release.

Usage Guidelines

Use this command to enable AAL2 common part sublayer (CPS) subcell multiplexing when the Cisco MC3810 interoperates with other equipment that uses subcell multiplexing.

Examples

The following example enables AAL2 CPS subcell multiplexing on a Cisco MC3810:

router(config)# voice service voatm
router(config-voice-service)# session protocol aal2
router(config-voice-service-session)# subcell-mux

Syntax Description

pots	Specifies telephony voice service (not supported)
voatm	Specifies Voice over ATM encapsulation
vofr	Specifies Voice over Frame Relay encapsulation (not supported)
voip	Specifies Voice over Internet Protocol encapsulation (not supported)

Defaults

There is no default setting for this command.

Command Modes

Global configuration

Command History

Release	Modification
12.1(1)XA	This command was introduced on the Cisco MC3810 series.
12.1(2)T	This command was implemented in the 12.1(2)T release.

Usage Guidelines

Use the voice service command to switch to the voice-service configuration mode from the global configuration mode and to specify a voice encapsulation type. Use the exit command to exit the voice-service configuration mode and return to the global configuration mode.

Examples

The following example shows how to access the voice-service configuration mode and specify VoATM voice encapsulation, beginning in global configuration mode:

router(config)# voice service voatm
router(config-voice-service)#

Syntax Description

This command has no arguments or keywords.

Defaults

Debugging for AAL2 sessions is not enabled.

Command History

Release	Modification
12.1(1)XA	This command was introduced on the Cisco MC380 series.
12.1(2)T	This command was implemented in the 12.1(2)T release.

Usage Guidelines

Use this command when troubleshooting an AAL2 trunk setup or teardown problem.

Examples

The following example shows sample output from the debug ccaal2 session command for a forced shutdown of a voice port:

router# debug ccaal2 session
router(config)# voice-port 1/1
router(config-voiceport)# shutdown
router(config-voiceport)#
3d21h:%Voice port in use.  Force shutdown.
3d21h:%Voice-port 1/1 is down.
3d21h:ccaal2_call_disconnect:peer tag 0
3d21h:ccaal2_evhandle_call_disconnect:Entered
3d21h:ccaal2_call_cleanup:freeccb 1, call_disconnected 1ccaal2_receive:xmitFunc is NULL
ccaal2_receive:xmitFunc is NULL
 
3d21h:starting incoming timer:Setting accept_incoming to FALSE and 
3d21h:timer 2:(0x126AD48)starts - delay (70000)
3d21h:ccaal2_call_cleanup:Generating Call record
3d21h:cause=81 tcause=81    cause_text=unspecified
3d21h:ccaal2_call_cleanup:ccb 0x1506A84, vdbPtr 0x15ACFD0
        freeccb_flag=1, call_disconnected_flag=1
3d21h:%LINK-3-UPDOWN:Interface FXS 1/1, changed state to Administrative Shutdown

The following example shows sample output from the debug ccaal2 session command for a trunk setup on a voice port:

router(config-voiceport)# no shutdown
router(config-voiceport)#
3d21h:%Voice-port 1/1 is up.
3d21h:%LINK-3-UPDOWN:Interface FXS 1/1, changed state to up
3d21h:ccaal2_call_setup_request:Entered
3d21h:ccaal2_evhandle_call_setup_request:Entered
3d21h:ccaal2_initialize_ccb:preferred_codec set(-1)(0)
3d21h:ccaal2_evhandle_call_setup_request:preferred_codec set(5)(40). VAD is 0
3d21h:ccaal2_call_setup_trunk:subchannel linking successful
 
3d21h:ccaal2_caps_ind:PeerTag = 2007
3d21h:     codec(preferred) = 1, fax_rate = 2, vad = 1
3d21h:     cid = 25, config_bitmask = 0, codec_bytes = 40, signal_type=8
3d21h:encap VOAAL2
3d21h:%HTSP-5-UPDOWN:Trunk port(channel) [1/1] is up

Related Commands

Command	Description
show debug	Shows which debug commands are enabled.

Syntax Description

all_dsp	Display messages to and from the DSP.
from_dsp	Display messages from the DSP.
to_dsp	Display messages to the DSP.

Defaults

Debugging for display of AAL2 packets is not enabled.

Command History

Release	Modification
12.1(1)XA	This command was introduced on the Cisco MC3810 series.
12.1(2)T	This command was implemented in the 12.1(2)T release.

Usage Guidelines

Syntax Description

all_dsp	Display messages to and from the DSP.
from_dsp	Display messages from the DSP.
to_dsp	Display messages to the DSP.

Defaults

Debugging for display of AAL2 packets is not enabled.

Command History

Release	Modification
12.1(1)XA	This command was introduced on the Cisco MC3810 series.
12.1(2)T	This command was implemented in the 12.1(2)T release.

Usage Guidelines

Syntax Description

alarms	Display type 3 alarm packets.
alltype3	Display all type 3 packets.
cas	Display type 3 CAS signaling packets.
dialed	Display type 3 dialed digit packets.
faxrelay	(Not supported) Display type 3 fax relay packets.
state	Display type 3 user state packets.
all_dsp	Display messages to and from the DSP.
from_dsp	Display messages from the DSP.
to_dsp	Display messages to the DSP.

Defaults

Debugging for display of AAL2 packets is not enabled.

Command History

Release	Modification
12.1(1)XA	This command was introduced on the Cisco MC3810 series.
12.1(2)T	This command was implemented in the 12.1(2)T release.

Usage Guidelines

This is the preferred debug command for displaying specific types of control packets. It is usually preferable to specify a particular type of control packet rather than alltype3, to avoid excessive output display and CPU utilization.

Examples

The following example shows a sample output from the debug vpm voaal2 type3 command, where the example selection is to display type 3 CAS packets sent from the DSP:

router# debug vpm voaal2 type3 cas from_dsp
Aal2 trace is on
router#
3d21h:TYPE 3, len = 8, cid = 25, uui = 24
3d21h:CAS
 redundancy = 3, timestamp = 4, signal = 5
- 19 13 8 C0 4 5 F 68 -
 
3d21h:TYPE 3, len = 8, cid = 25, uui = 24
3d21h:CAS
 redundancy = 3, timestamp = 4, signal = 5
- 19 13 8 C0 4 5 F 68 -
 
3d21h:TYPE 3, len = 8, cid = 25, uui = 24
3d21h:CAS
 redundancy = 3, timestamp = 4, signal = 5
- 19 13 8 C0 4 5 F 68 -

Related Commands

Command	Description
debug vpm voaal2 type1	Displays type 1 (voice) AAL2 packets sent to and received from the DSP.
debug vpm voaal2 type3	Displays type 3 (control) AAL2 packets sent to and received from the DSP.
show debug	Shows which debug commands are enabled.