Routing Using Matching and Calculated LSP Next Hops

Normally, a route table prefix is associated with a gateway or next hop IP address.

Using MPLS, a route table prefix can also be associated with an LSP that can be used as the next hop. There are two types of LSP next hops that can be used to route a packet to its destination:

Matching and Calculated LSP Next Hops illustrates the concept of matching and calculated LSPs.

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Matching and Calculated LSP Next Hops

Label Bindings for LSR A describes the label bindings in the MPLS forwarding table for LSR A that are maintained for FECs reachable via LSR A to LSR C, shown in Matching and Calculated LSP Next Hops.

Table 1. Label Bindings for LSR A
Destination Next Hop Matching LSP Next Hop Label Calculated LSP Next Hop Label
10.1.1.1/32 10.2.1.1 31 30
10.0.1.0/24 10.2.1.1 32 31
10.0.2.0/24 10.2.1.1 33 31
10.0.3.0/24 10.2.1.1 34 31