4-30
Cisco VISM Installation and Configuration Guide
Release 3.0, Part Number OL-2521-01 Rev. D0, June 2004
Chapter4 Configuring VISM Features
Configuring VISM Features
Step 4 Type the cnferl command, the echo-ret-loss argument value, and press Enter to specify the ECAN
algorithm’s return echo loss applied by ECAN DSPs, in decibels. Specify the echo-ret-loss argument
with one of the following values:
•echo-ret-loss:
–
1 = 0 dB
–
2 = 3 dB
–
3 = 6 dB
–
4 = 1 dB
Step 5 Type the cnfconvbdpol command, lcn, carrier-loss-pol, and cac-reject-pol argument values, and press
Enter to specify the fax/modem upspeed connection admission control (CAC) failure and carrier loss
policies for a channel. Specify the arguments with the following values:
•lcn (logical channel number): In the range from 131 to 51 0.
•carrier-loss-pol (carrier loss policy):
–
1 = Revert to the previous codec
–
2 = Maintain the upspeed codec
–
3 = Unspecified
•cac-reject-pol (CAC rejection policy):
–
1 = Delete the connection
–
2 = Maintain the connection
–
3 = Unspecified
You have completed enabling and configuring ECAN on your lines. Proceed to the “Configuring Jitter”
section on page 4-30.
Configuring Jitter
You can dejitter the voice payload to improve the quality of the egress voice stream.
Note If your application uses the AAL2 trunking operation mode, you cannot change the jitter parameters
while the CIDs are active.
Complete the following steps to specify and configure jitter mode:
Step 1 Type the cnfjtrmode command, the jitter-mode argument value, and press Enter to set the jitter mode.
Specify the jitter-mode argument with one of the following values:
•1 = Fixed buffer size; recommended value if the jitter amount is expected to be constant or near
constant.
•2 = Adaptive; you specify a starting buffer size and VISM adapts the buffer size to handle jitter.
Step 2 If you chose a fixed buffer size in Step 1, you have completed configuring jitter. Proceed to the
“Configuring the ATM Network Side” section on page 4-31. If you chose an adaptive buffer size in
Step 1, proceed to Step 3.