Echo on SCN, inter-network calls only

[treeco]

I have a SCN setup, with a 412 at main site, and 6x406 at the remote sites. I am getting reports of random echo on inter-system calls only, not on external calls.

The network guys assigned me ports 24 on the switches at all sites and have assured me that the port is set for QOS with 46 voice and 34 (i think that is they said) data, which should be correct.

The systems all have newer VPN cards, the 406's have VPN 8's, and the 412 has a VPN 20 in it

The echo is not on all calls, and not all the time, I have not been able to duplicate it during my testing. Is there any settings i can do on the IPoffice side to help eleviate this?

 

[tlpeter]

if you only have echo on calls from ipoffice to ipoffice then it is a network problem
the cards you mean are vcm card
they provide a voice channel (from data to voice andback)
if QOS is set then the bandwidth is not big enough
echo will say delay in voice packets ,thats all

 

[treeco]

The network is a gigabit backbone, not sure how much is slotted to the phonesystem, what would be the appropriate amount to tell the network people to have reserved for me? currently they have 512m reserved. This would give me 8 channels with 64k each...

 

[IPhello]

If you are setting your VoIP lines to auto select there would be some random echo occasionally (especially during call setup). I would try setting your voice compression to a hard rate at each end.

 

[intrigrant]

If the echo's happen at busy hours hen you might have a bandwith problem.
Using fixed codec settings on IP trunks is always the best thing to do, i advise the G.729 codec as it gives the best bandwith use / quality performance.

Do you have "direct mediapath" selected? If yes then there may be a network problem between the remote sites as the voice packets travel directly between the callers and not through the main site.

If not then enable "direct mediapath", it could decrease the time a packet runs ove the connection wich is basically the most common cause of echo's.