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Configuring the FAT Flow Label for FEC 128 VPLS Pseudowires for Load-Balancing MPLS Traffic

This topic shows how to configure flow-aware transport of pseudowires (FAT) flow labels for forwarding equivalence class (FEC) 128 virtual private LAN service (VPLS) pseudowires for load-balancing MPLS traffic.

Before you begin:

  1. Configure the device interfaces and enable MPLS on all the interfaces on the provider edge (PE) router.

  2. Configure MPLS and an LSP from the ingress PE router to the remote egress PE router.

  3. Configure an interior gateway protocol (IGP) on the PE router and provider (P) routers.

  4. Configure the circuits between the PE routers and the customer edge (CE) routers.

  5. Configure LDP on all the interfaces.

FAT flow labels enable load-balancing of MPLS packets across equal-cost multipath (ECMP) paths or link aggregation groups (LAGs) without the need for deep packet inspection of the payload. FAT flow labels can be used for LDP-signaled FEC 128 and FEC 129 pseudowires for VPLS and virtual private wire service (VPWS) networks.

You can configure FAT flow labels to be signaled by LDP on FEC 128 VPLS pseudowires by including the flow-label-transmit and flow-label-receive configuration statements at the [edit routing-instances instance-name protocols vpls] hierarchy level. This configuration sets the T bit and R bit advertisement to 1 (the default being 0) in the Sub-TLV field, which is one of the interface parameters of the FEC for the LDP label-mapping message header. This configuration is applicable for all the pseudowires providing full mesh connectivity from the VPLS routing instance to all its neighbors.

To configure the FAT flow label for an FEC 128 VPLS pseudowire, on the ingress PE router:

  1. Configure the FEC 128 VPLS routing instance.
  2. Configure the routing instance to signal the capability to push the flow label in the transmit direction to the remote PE router.
  3. Configure the routing instance to signal the capability to pop the flow label in the receive direction to the remote PE router.
  4. Verify and commit the configuration.

    For example:

  5. Repeat the configuration on the remote egress PE router.