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. And see here for current known issues.

New Member

Dimensioning Router because transcoding issues.

I want to deploy the following scenario:

My Telephony Service Provider give me a Digital E1 (30-channels PCM) on Main Site and I want to receive them with a router and VWIC-1MFT-E1 to transmit via ethernet to another site with other router with VWIC-1MFT-E1 to connect with one PBX. I am going to use G.729 codec in ethernet media to reduce bandwidth. I am a little confuse of I must take care about transcoding issues for router's dimensioning.

Thanks in advance for any help and tips.

Daniel Toro

Hall of Fame Super Silver

Re: Dimensioning Router because transcoding issues.

Hello Daniel,

if you would use G.711 codec on the voip dial peer to the othe router you wouldn't need to transcode.

Transcoding is the operation of converting in real time between one codec and another and requires additional DSP resources.

You will find out that it is easier to use G.711 for your application instead of adding DSPs to the router.

in adding DSP resources for transcoding you should take in account possible 30 B channels to be converted at the same time

for example you would need a PVDM2-32

(2 DSPs) to handle 32 real time transcoding sessions

depending on your routers you may be able to install these additional modules or not

But again using G.711 is to be preferred for this application

Hope to help


New Member

Re: Dimensioning Router because transcoding issues.

Hello Giuseppe. Thank you very much for your help.

The critical problem is that the transport medium for voice traffic will be satellite link and how you understand that is a very expensive medium reason for what I require as much as possible reduce bandwidth.

In fact, my question would be: Could be solved by just putting a higher compression codec on dial-peer to other router?

What do you think?

Thanks again.


CreatePlease login to create content