Configuring PW APS

This chapter applies only to the NetEngine 8000 F1A.

Context

In a PW APS scenario, PW OAM detects the status of the active and standby PWs. When PW OAM detects a fault on the active PW, it immediately notifies PW APS of the fault, which is then triggered to perform an active/standby PW switchover. The PWs can be classified as single-segment PWs (SS-PWs) or multi-segment PWs (MS-PWs) or be classified as dynamic PWs or static PWs. See Figure 1 and Figure 2.

Figure 1 PW APS networking for MS-PWs

Figure 2 PW APS networking for SS-PWs

Pre-configuration Tasks

Before configuring PW protection, complete the following tasks:

• Configure IP addresses and an IGP on PEs.

• Establish public network tunnels or between PEs. The public network tunnels can be:

  • LDP tunnel: To establish an LDP tunnel, you must enable MPLS and MPLS LDP both globally and per interface on each public network node along the tunnel. If two PEs are indirectly connected, establish a remote LDP session between them.

  • TE tunnel: To establish a TE tunnel, you must enable MPLS, MPLS TE, and RSVP-TE both globally and per interface on each public network node along the tunnel, and enable CSPF in the MPLS view of the tunnel ingress.

    

    Because pseudo wire emulation edge-to-edge (PWE3) uses LDP to distribute VPN labels, you must globally enable MPLS LDP on PEs and establish remote MPLS LDP sessions if TE tunnels are used as public network tunnels.

    If the public network tunnels are not LDP tunnels, you must configure tunnel policies and apply them to these tunnels.

• Enable MPLS L2VPN on PEs.