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JN0-649 Exam - Question 15


Click the Exhibition button.

Referring to the exhibit, ServerA sends a single IP packet destined to 10.0.0.127.

Which two statements correctly describe the behavior of the resulting outbound VXLAN packets that contain the original packet destined to 10.0.0.127? (Choose two.)

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Correct Answer: BC

Router C will send a VXLAN packet destined only to router D and router E. This is due to the behavior of EVPN when handling Broadcast, Unknown Unicast, and Multicast (BUM) traffic, as the source leaf sends the packet to all VTEPs with the same VLAN/VNI. Once Router D receives the VXLAN packet destined to 10.0.0.127, it will treat it as unicast traffic and forward it to the appropriate destination. Router D will not replicate and send a copy of the received VXLAN packet to router E because the replication of BUM traffic is only handled by the ingress device, which is Router C in this scenario.

Discussion

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JoeSunOptions: BC
Dec 23, 2022

It is about how EVPN handle BUM traffic. The source leaf will send the unknown unicast traffic to all leaf that with same VLAN/VTEP.

Anarky19Options: AB
Jun 7, 2023

Router E will replicate and send a copy of the received VXLAN packet to router D Ingress Replication Ingress replication involves an ingress device replicating every incoming BUM packet and sending them as a separate unicast to the remote egress devices. Ingress replication happens through EVPN route type 3, also called as inclusive multicast ethernet tag (IMET) route

Anarky19Options: BD
Jun 7, 2023

Router C will send a VXLAN packet destined only to router D and router E Underlay Multicast: In underlay multicast, the underlay network replicates the traffic through a multicast group. Forwarding BUM traffic using underlay multicast requires the configuration of IP multicast in the underlay network. A single copy of the BUM traffic moves from the ingress or source VTEP towards the underlay transport network. The network forwards this copy along the multicast tree so that it reaches all egress or destination VTEPs participating in the given multicast group.

YunasOptions: BC
Aug 23, 2023

BC is correct, ingress BUM traffic would be sent by local PE, other PEs will not replicate BUM traffic to remote PEs

harrypogiOptions: BC
Sep 23, 2023

bc is correct

somanyquestionsOptions: BC
Oct 19, 2023

The source leaf (C) will send the broadcast traffic to all VTEPs of leafs that with same VLAN (D and E). those routers will not forward it again...