Nokia SR Linux EVPN and Data Center Interconnect 4A0-D03 Question # 4 Topic 1 Discussion
4A0-D03 Exam Topic 1 Question 4 Discussion:
Question #: 4
Topic #: 1
Consider the exhibit.
Leaf-1 has received an ARP request from host-1 for host-2. Leaf-1 has added host-1's MAC address in its MAC table and host-1's MAC/IP addresses in its proxy-ARP table.
Which of the following steps is FALSE?
A.
Leaf-1 sends a route-type 2 EVPN update with host-1's MAC with the IP address set to 0.0.0.0 to the remote peers.
B.
Leaf-1 sends a route-type 2 EVPN update with host-1's MAC with the IP address set to 192.168.100.1 to the remote peers.
C.
The remote peers ignore the EVPN update with the IP address set to 0.0.0.0 and use the update with the IP address set to 192.168.100.1 to populate their MAC forwarding tables.
D.
The remote peers generate a gratuitous ARP towards their directly connected hosts to announce the learned IP/MAC mapping information.
Comprehensive and Detailed 150 to 250 words of Explanation From [SR Linux EVPN and Data Center Interconnect/Course Guide/topics]:
When Leaf-1 receives an ARP request from Host-1, it learns the source MAC address in the local MAC table and learns the source IP/MAC binding in the proxy ARP table. For EVPN distribution, the relevant control-plane advertisement is an EVPN route type 2 MAC/IP advertisement containing Host-1's MAC and the actual host IP address, 192.168.100.1. This allows remote PEs to populate their EVPN-derived forwarding and proxy ARP state with the correct endpoint binding. Option A is false because advertising the host MAC with the IP address set to 0.0.0.0 does not represent the learned MAC/IP binding required for proxy ARP synchronization. A MAC-only RT-2 advertisement may exist in EVPN contexts, but the question specifically states that Leaf-1 has learned the MAC/IP binding through ARP and is distributing that information. Therefore, the valid advertisement must include the real host IP address. Remote PEs use the MAC/IP route to learn the endpoint, not an all-zero IP placeholder for this proxy ARP learning event. Reference: EVPN RT-2 MAC/IP advertisement, proxy ARP table population, endpoint synchronization.
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