What Is CBQoS?

CBQoS is Cisco’s implementation of class-based traffic routing. As part of Cisco IOS 12.4(4)T and above, CBQoS enables Cisco network devices to set the TOS/Diffserv bits in IP headers, determining what priority a set of IP packets is given in the routing queue.

How traffic is classed becomes important when an interface link becomes congested. In this case, applied policy rules result in more highly prioritized traffic continuing to smoothly pass through the network while less highly prioritized traffic gets delayed or even dropped.

CBQoS also includes features that keep track of QoS packet routing activity in the MIB database. In terms of monitoring how QoS policies are affecting traffic on the network, NTA polls network devices for CBQoS MIB data over SNMP, through the default port (161).

For information on configuring CBQoS on your Cisco devices, refer to the Cisco website.