Configuring Forwarding Policy Options

Class-of-service (CoS)-based forwarding (CBF) enables you to control next-hop selection based on a packet's class of service and, in particular, the value of the IP packet's precedence bits.

For example, you might want to specify a particular interface or next hop to carry high-priority traffic while all best-effort traffic takes some other path. When a routing protocol discovers equal-cost paths, it can pick a path at random or load-balance across the paths through either hash selection or round robin. CBF allows path selection based on class.

To configure CBF properties, you can include the following statements at the [edit class-of-service] hierarchy level of the configuration:

class-of-service {

    forwarding-policy {

        next-hop-map map-name {

            forwarding-class class-name {

                next-hop [ next-hop-name ];

                lsp-next-hop [ lsp-regular-expression ];

            }

        }

        class (CoS-Based Forwarding) class-name {

            classification-override {

                forwarding-class class-name;

            }

        }

    }

}

This chapter discusses the following topics:

• Configuring CoS-Based Forwarding
• Overriding the Input Classification
• Example: Configuring CoS-Based Forwarding