network audit program

Originally, network audit program equipment marked Call-Signaling traffic to DSCP AF31. However, the assured forwarding classes, as defined in RFC 2597, were intended for flows that could be subject to markdown and aggressive dropping of marked-down values. Marking down and aggressively dropping Call-Signaling could result in noticeable delay to dial tone (DDT) and lengthy call-setup times, both of which generally translate into poor user experiences

Therefore, the QoS Baseline changed the marking recommendation for Call-Signaling traffic to DSCP CS3 because Class-Selector code points, defined in RFC 2474, are not subject to such markdown and aggressive dropping as network audit program.