The Differentiated Services Code Point (DSCP) or DiffServ is a packet prioritization scheme. DiffServ uses the Type of Service (ToS) byte in the packet header to indicate the forwarding class of the packet and Per Hop Behaviors (PHBs). After the packets are marked with the forwarding class, the interior routers and gateways use this ToS byte to differentiate the treatment of packets.

A DiffServ policy must be established across the entire IP network. The DiffServ values used by Communication Manager and by the IP network infrastructure must be the same.

If you have a Service Level Agreement (SLA) with a service provider, the volume of traffic of each class that you can inject into the network is limited by the SLA. The forwarding class is directly encoded as bits in the packet header. After the packets are marked with the forwarding class, the interior nodes, including routers and gateways, can use this information to differentiate treatment of packets.