Configuring LSP Stitching Cross-Connects Using CCC
LSP stitching cross-connects “stitch” together LSPs to join two LSPs. For example, they stitch together LSPs that fall in two different traffic engineering database areas. The topology in Figure 1 illustrates an LSP stitching cross-connect. In this topology, the network is divided into two traffic engineering domains. CCC allows you to establish an LSP between the two domains by stitching together LSPs from the two domains. For LSP stitching to work, the LSPs must be dynamic LSPs, not static.
Figure 1: LSP Stitching Cross-Connect
Without LSP stitching, a packet traveling from Router A to Router C is encapsulated on Router A (the ingress router for the first LSP), de-encapsulated on Router B (the egress router), and then reencapsulated on Router B (the ingress router for the second LSP). With LSP stitching, you connect LSP1 and LSP2 into a single, stitched LSP, which means that the packet is encapsulated once (on Router A) and de-encapsulated once (on Router C).
You can use LSP stitching to create a seamless LSP for LSPs carrying any kind of traffic.
To configure LSP stitching cross-connects, configure the two LSPs that you are stitching together on the two ingress routers. Then on the interdomain router (Router B in Figure 1), you define the connection between the two LSPs. The connection joins the LSP that comes from the connection’s source to the LSP that leads to the connection’s destination.
You can configure these statements at the following hierarchy levels:
- [edit protocols connections]
- [edit logical-systems logical-system-name protocols connections]
Example: Configuring an LSP Stitching Cross-Connect
Configure a full-duplex LSP stitching cross-connect between Router A and Router C. To do this, you configure Router B, which is the interdomain router. See the topology in Figure 2.
Figure 2: Example Topology of LSP Stitching Cross-Connect
