PBR gives you a flexible means of routing packets by allowing you to configure a defined policy for traffic flows, which lessens reliance on routes derived from routing protocols. To this end, PBR gives you more control over routing by extending and complementing the existing mechanisms provided by routing protocols. PBR allows you to set the IPv6 precedence. It also allows you to specify a path for certain traffic, such as priority traffic over a high-cost link.
PBR for IPv6 may be applied to both forwarded and originated IPv6 packets. For forwarded packets, PBR for IPv6 will be implemented as an IPv6 input interface feature, supported in the process, Cisco Express Forwarding, and distributed Cisco Express Forwarding forwarding paths.
Policies can be based on IPv6 address, port numbers, protocols, or packet size. For a simple policy, you can use any one of these descriptors; for a complex policy, you can use all of them.
PBR allows you to perform the following tasks:
- Classify traffic based on extended access list criteria. Access lists, then, establish the match criteria.
- Set IPv6 precedence bits, giving the network the ability to enable differentiated classes of service.
- Route packets to specific traffic-engineered paths; you might need to route them to allow a specific quality of service (QoS) through the network.
Policies can be based on IPv6 address, port numbers, protocols, or size of packets. For a simple policy, you can use any one of these descriptors; for a complex policy, you can use all of them.
PBR allows you to classify and mark packets at the edge of the network. PBR marks a packet by setting its precedence value. The precedence value can be used directly by routers in the network core to apply the appropriate QoS to a packet, which keeps packet classification at your network edge.