Cisco Cisco IOS Software Release 12.2(8)T

ATM Software Segmentation and Reassembly (SAR)

Configuration Tasks for AAL2 Trunking with CAS

Cisco IOS Release 12.2(8)T

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 common to the Cisco 2600 series and the
Cisco 3660 routers.

You can configure a Cisco 2600 series router or a Cisco 3660 as either a CAC master or a CAC slave.
By default, this 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 or a Cisco 3660 configured as a master
always performs CAC during fax/modem upspeed. A Cisco 2600 series router or a Cisco 3660
configured as a slave sends a request for CAC to the CAC master.

To configure a Cisco 2600 series router or a Cisco 3660 as a CAC master, complete the following steps
beginning in global configuration mode:

To return a Cisco 2600 series router or a Cisco 3660 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)# cac master

Configures this Cisco 2600 series router or a
Cisco 3660 as a CAC master.

Step 4

Router(config-voice-service-session)# end

Exits configuration mode.