Avaya recommends marking call control traffic the same as voice traffic, COS=5 and DSCP=46, and therefore putting call control traffic in the same priority queue with voice during congestion.

The rational is that call control and inter-IPSI traffic is as crucial as voice and should be treated as such.

This is different than Cisco's recommendation as described in the Enterprise QoS SRND, where call control is marked as COS=3/DSCP=24 and treated via bandwidth quarantees.

Is Avaya's approach a sound approach and are there advantages to their approach? We will be deploying Avaya IP phones along with Cisco 3750's and 6509's as access-layer switches.

Any and all comments are appreciated.