Example: Configuring an Egress Protection LSP for a Layer 2 Circuit

Egress protection LSPs are supported on Juniper Networks MX Series routers only. This requirement applies to the PE routers facilitating the egress protection LSP.

If there is a link or node failure in the core network, a protection mechanism such as MPLS fast reroute can be triggered on the transport LSPs between the PE routers to repair the connection within tens of milliseconds. An egress protection LSP addresses the problem of when a link failure occurs at the edge of the network (for example, a link failure between a PE router and a CE device). Egress protection LSPs do not address the problem of a node failure at the edge of the network (for example, a failure of a PE router). An egress protection LSP is an RSVP-signaled ultimate hop popping LSP.

This example includes the following configuration concepts and statements that are unique to the configuration of an egress protection LSP:

• context-identifier—Specifies an IPV4 address used to define the pair of PE routers participating in the egress protection LSP. The context identifier is used to assign an identifier to the protector PE router. The identifier is propagated to the other PE routers participating in the network, making it possible for the protected egress PE router to signal the egress protection LSP to the protector PE router.

• egress-protection—Configures the protector information for the protected Layer 2 circuit and configures the protector Layer 2 circuit at the [edit protocols l2circuit] hierarchy level. Configures an LSP as an egress protection LSP at the [edit protocols mpls label-switched-path lsp-name] hierarchy level. It also configures the context identifier at the [edit protocols mpls] hierarchy level.

• protected-l2circuit—Specifies which Layer 2 circuit is to be protected by the egress protect LSP. This statement includes the following sub-statements: ingress-pe, egress-pe, and virtual-circuit-id. These sub-statements specify the address of the PE router at the ingress of the Layer 2 circuit, the address of the PE router at the egress of the Layer 2 circuit, and the Layer 2 circuit’s identifier respectively.

• protector-interface—Specify the interface used by the egress protection LSP. In the event of a local link failure to a CE device, the egress protect LSP uses the interface specified to communicate with the protector PE router.

• protector-pe—Specify the IPv4 address of the protector PE router. The protector PE router must have a connection to the same CE device as the protected PE router for the egress protect LSP to function. This statement includes the following sub-statements: context-identifier and lsp. The lsp statement specifies the LSP to be used as the actual egress protection LSP.

Topology

Figure 1: Egress Protection LSP Configured from Router PE2 to Router PE3

Pseudowires are configured along two paths, one from router PE1 to router PE2 (pseudowire 12) and one from router PE1 to router PE3 (pseudowire 13). In the event of a failure on the link between router PE2 and device CE2, traffic is switched to the egress protection LSP configured between router PE2 and router PE3 (the protector PE router):

• Device CE1—Traffic origin

• Router PE1—Ingress PE router

• Router PE2—Egress PE router

• Router PE3—Protector PE router

• Device CE2—Traffic destintation

This example shows how to configure routers PE1, PE2, and PE3.

• CLI Quick Configuration
• Step-by-Step Procedure
• Results