DiffServ

Differentiated Services. Defined in RFC 2474 and 2475, DiffServ is an architecture for implementing scalable service differentiation in the Internet. Each IP header has a DiffServ (DS) field, formerly known as the Type of Service (TOS) field. The value in this field defines the QoS (Quality of Service) priority the packet will have throughout the network by dictating the forwarding treatment given to the packet at each node.

DiffServ is a flexible architecture that allows for either end-to-end QoS or intra-domain QoS by implementing complex classification and mapping functions at the network boundary or access points. In the Extreme Networks implementation, you can configure the desired QoS by replacing or mapping the values in the DS field to egress queues that are assigned varying priorities and bandwidths.