rsvp with HDLC

[foliveri]

I need to enable QoS for two voice channels, in two 2610 routers connected via HDLC. For what I've read in the documentation, the following commands should be sufficient to reserve 75% of the bandwith for the

voice calls:

...

int serial 0/0

ip rsvp bandwidth

fair-queue

...

dial-peer voice 101 voip

req-qos controlled-load

...

But the voice quality quickly degrades as soon as the data traffic increases. I think I'm missing something here, thanks for any suggestion. (If possible I prefer not to change to frame-relay encapsulation)

[scadora]

What IOS version are you using on the 2600s?

[foliveri]

I'm using 12.0(4) in one of the routers, and the other is a 11.3. I'll upgrade the later as soon as possible.

[scadora]

I believe 12.1(5)T or higher is recommended for RSVP. It will give you RSVP with LLQ which will do a better job of limiting delay bounds than WFQ alone can.