ECE495 Chapter Notes - Chapter 2: Voip Phone, Multiprotocol Label Switching, Frame Relay

• School: University of Alberta
• Department: Electrical and Computer Engineering
• Course: ECE495
• Professor: mint

Document Summary

Conceptually, diffserv qos involves three steps: traffic must be identified and then classified into groups, traffic must be marked on trust boundaries, policies must be created to describe the per-hop behavior for classified traffic. Diffserv qos relies on the classification of traffic, to provide differentiated levels of service on a per-hop basis. Access-lists can be used to identify traffic for classification, based on address or port. However, a more robust solution is cisco"s network-based. Application recognition (nbar), which will dynamically recognize standard or custom applications, and can classify based on payload. Once classification has occurred, traffic should be marked, to indicate the required level of qos service for that traffic. Marking can occur within either the layer-2 header or the layer-3 header. The point on the network where traffic is classified and marked is known as the trust boundary. Qos marks originating from outside this boundary should be considered untrusted, and removed or changed.