For Layer 2 Policy-Based Forwarding (PBF) redirect actions, a far-end router may discard redirected packets when the PBF changes the destination IP interface the packet arrives on. This happens when a far-end IP interface uses a different MAC address than the IP interface reachable via normal forwarding (for example, one of the routers does not support a configurable MAC address per IP interface). To avoid the discards, operators can deploy egress destination MAC rewrite functionality for VPLS SAPs (config>service>vpls>sap>egress>dest-mac-rewrite). Figure: Layer 2 policy-based forwarding (PBF) redirect action shows a deployment.
When enabled, all unicast packets have their destination MAC rewritten to operator-configured value on an Layer 2 switch VPLS SAP. Multicast and broadcast packets are unaffected. The feature:
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Is supported for regular and split-horizon group Ethernet SAPs in a regular VPLS Service
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Is expected to be deployed on a SAP that faces far-end IP interface (either a SAP that is the target of PBF action, as shown in Figure: Layer 2 policy-based forwarding (PBF) redirect action, or a VPLS SAP of a downstream Layer 2 switch that is connected to a far-end router—not shown).
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Applies to any unicast egress traffic including LI and mirror.
Restrictions:
Mutually exclusive with SAP MAC ingress and egress loopback feature: tools perform service id service-id loopback eth sap sap-id {ingress | egress} mac-swap ieee-address