Overview

A static Constraint-based Routed Label Switched Path (CRLSP) is established by manually specifying CRLSP setup information on the ingress, transit, and egress nodes of the forwarding path. The CRLSP setup information includes the incoming label, outgoing label, and required bandwidth. If the device does not have enough bandwidth resources required by a CRLSP, the CRLSP cannot be established.

Static CRLSPs consume fewer resources, but they cannot automatically adapt to network topology changes. Therefore, static CRLSPs are suitable for small and stable networks with simple topologies.

Follow these guidelines to establish a static CRLSP:

• Configure the ingress node as follows:

  • Specify the outgoing label for the CRLSP, the next hop or the outgoing interface to the next hop, and the required bandwidth.

  • Create an MPLS TE tunnel interface.

  • Specify the static CRLSP for the tunnel interface.

  The tunnel interface adds the outgoing label of the static CRLSP to each packet, and forwards the packet to the next hop or out of the outgoing interface.

• A transit node swaps the label carried in a received packet with a label. It forwards the packet to the next hop or out of the outgoing interface. You must specify the incoming label, the outgoing label, the next hop or the outgoing interface, and the required bandwidth on each transit node.

• If it is not configured with the penultimate hop popping function, an egress node pops the incoming label of a packet. It performs label forwarding according to the inner label or IP forwarding. You are only required to specify the incoming label on the egress node.

• The outgoing label specified on an LSR must be the same as the incoming label specified on the directly connected downstream LSR.