G.711 over T1

[sknorr]

I want to send VoIP traffic over my WAN link to a remote office. Have a 2610xm on one end and a 3640 on the other. They each have T1 CSU/DSU cards to connect. My question is do I have to set anything special up for G.711 compression that is being used for IP phones? Can I use HDLC? Note the phone gateways are not on the router, they are a third part that will connect to a LAN segment on each end.

[thisisshanky]

By default most VoIP boxes should be doing g711 compression unless they do g729 by default. Default encap. on Cisco routers is HDLC by default. Since its a T1, and theoretically a g711 call takes 64 kbps, (80 kbps with overhead)...the number of calls that can go across is roughly 19.

If there is data and voice going across the same T1, you will need to apply some QOS on the link. PQ-CBWFQ with RTP header compression is the best..

[jolo07310]

I thought LLQ is the best for WAN?? Point me out if I am wrong?

[craig.watson]

CBFQ with a strict PQ is exactly what LLQ is. Some people use the LLQ acronymn, others spell it out like hanky did. Either way, its the same thing.

[thisisshanky]

I should have posted it as LLQ, but LLQ is nothing but PQ for Voice and CBWFQ for the rest...Hence LLQ = PQ+CBWFQ