Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

iLBC codec packetization issue

I have video call between two phone as below

9971 -- CME --- CUBE ----CUCM --- 9971   (delay offer)

call from cme end to CUCM end works (video and audio) h264 and iLBC

call from CUCM end to cme end connect(video works) but no audio (can see on phone both ends Rcvr discarded) due to cucm end doing 30ms and CME end doing 20ms


Debugs on CUBE shows CME send offer with 30ms but CUBE send offer to CUCM without any ptime ?

CUBE has codec transparent on both ends.



New Member

Try asymmetric payload full

Try asymmetric payload full under voice service voip > sip.

Do this on both CUBE and CME.

use codec ilbc mode 30 at

use codec ilbc mode 30 at your CME End

Cisco Employee

I had the same issue. I

I had the same issue. I resolved it two ways.

The less preferred way:

Go to the inbound and outbound dial-peers on the CUBE. On the dial-peer enter the command

codec ilbc mode #

where # is the lower of the two ptime values. In this instance 20 (from CME side) is lower so the command for this scenario is

codec ilbc mode 20

The more preferred way:

We can tell CUBE to passthru the SDP. I recommend doing it on the dial-peer instead of doing it globally:

CUBE#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
CUBE(config)#dial-peer voice <tag>
CUBE(config-dial-peer)#voice-class sip pass-thru content sdp
Building configuration...