QuestionQ4

EVPN for ELAN services

Proxy-ARP/ND is operational for a VPLS. Which of the following statements is FALSE?

  • A The PE has proxy-ARP and dynamic-populate enabled for the VPLS.
  • B The proxy-ARP table is populated by snooping IP packets received from remote PEs.
  • C When the PE learns a local host IP address, it adds an entry into its proxy-ARP table.
  • D The PE advertises a MAC/IP route that includes the MAC and IP address of a local host.
Explanation

In a VPLS/EVPN deployment, proxy-ARP/ND table entries for locally attached hosts are created by snooping ARP, Gratuitous ARP, or IPv6 Neighbor Advertisement messages received on local SAPs/SDP bindings (i.e., from CEs directly attached to that PE), not by snooping IP data packets arriving from remote PEs over the core. Once a local entry is learned, the PE advertises that host's MAC and IP address to remote PEs via a BGP EVPN MAC/IP Advertisement (Route Type 2) route. Remote PEs then populate their own proxy-ARP/ND tables with these EVPN-learned entries by importing the received BGP routes — this is a control-plane mechanism, not data-plane snooping of IP traffic from remote PEs. Traffic arriving on core-facing/network interfaces from remote PEs is explicitly excluded from ARP/ND snooping in standard implementations. Therefore, the statement claiming the proxy-ARP table is populated by snooping IP packets received from remote PEs is incorrect.

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