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New Member


Hi, my name is Alexandre and I've been work with

Cisco router for the past two years.

I configured a lot of VOIP and VOFR and many

VPN connections with 3DES.

Recently I got a problem:

Imagine the following situation:

I have two routers in different places and I have to configure a 3DES VPN between these routers and

also I have to do VOIP and multicast traffic such

as video conference and EIGRP updates.

One router is a 2620 with 4 E&M analog voice ports

and in the other side I have a 3640 with an E1. And

the bandwidth of the link is 128kbps

My questions are :

- Voice packets can be encrypted ?

- I know that multicast packets can't flow with a

VPN I have to configure a tunnel interface to work,

is that right ?

- Does the proccess of encryptation can cause a lot

of delay in the voice packets?

- And finally is it possible to do this kind of configuration, because I didn't find any sample configuration in Cisco's web page.

New Member

Re: VOIP over VPN

Hi Alexandre!

I have deployed a lot of VPN like yours, but I've never passed the voip traffic via crypto tunnels.

Have in mind, that the proccess to encrypt the traffic, takes a lot of time (i say a lot, talking about voice traffic), 20ms added for voice, could be considerable. Much more, if you are talking about a 128kbps link.