CCNP Virtualization Practice Question
A network engineer is designing a VXLAN EVPN fabric using Cisco Nexus 9000 switches. The engineer must choose a multicast mode for BUM (Broadcast, Unknown unicast, Multicast) traffic replication. Which two statements are true regarding the use of multicast in a VXLAN EVPN fabric? (Choose two.)
⚠ Common exam trap
The trap here is assuming multicast replaces BGP EVPN or that ingress replication is used alongside multicast, when in fact they are alternative methods for BUM traffic handling.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Each VNI is typically mapped to a unique multicast group address.
In a VXLAN EVPN fabric using multicast for BUM traffic, the underlay must support multicast routing, typically PIM SM with an RP. Each VNI is mapped to a unique multicast group address, and VTEPs join the group for their VNIs. This allows BUM traffic to be replicated to all VTEPs in the VNI. BGP EVPN is still used for control plane learning.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Ingress replication is required when using multicast mode.
Why it's wrong here
Ingress replication is an alternative to multicast for BUM traffic handling. In ingress replication, the ingress VTEP replicates the BUM packet and sends it unicast to each remote VTEP in the VNI. This does not require multicast in the underlay. Therefore, ingress replication is not required when using multicast mode; they are mutually exclusive approaches.
- ✗
Multicast mode eliminates the need for BGP EVPN for control plane learning.
Why it's wrong here
Multicast mode only affects how BUM traffic is replicated in the data plane. It does not replace the BGP EVPN control plane. BGP EVPN is still used to advertise MAC addresses and IP prefixes, providing control plane learning and avoiding flooding for unknown unicast. Multicast is used for broadcast and multicast traffic, but BGP EVPN remains essential for unicast MAC learning.
- ✓
Each VNI is typically mapped to a unique multicast group address.
Why this is correct
In a multicast-based VXLAN fabric, each VNI is mapped to a multicast group address. VTEPs that have the VNI configured join that group via IGMP. When a VTEP needs to send BUM traffic for that VNI, it sends the VXLAN-encapsulated packet to the multicast group, and all VTEPs in the group receive it. This mapping is configured on each VTEP.
- ✓
Multicast requires the underlay network to support PIM SM and an RP.
Why this is correct
When using multicast for BUM traffic replication in VXLAN, the underlay network must support multicast routing. Typically, PIM Sparse Mode (PIM SM) is used, and a Rendezvous Point (RP) is required to build the shared tree. Each VTEP joins a multicast group per VNI, and BUM traffic is sent to that group, allowing all VTEPs in the VNI to receive it.
- ✗
Multicast mode requires a separate multicast group for each VTEP.
Why it's wrong here
Multicast mode uses one multicast group per VNI, not per VTEP. All VTEPs that participate in a given VNI join the same multicast group. Using a separate group per VTEP would not provide the necessary replication to all VTEPs in the VNI. The group is shared among VTEPs to ensure BUM traffic reaches all members.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
This 350-401 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 350-401 exam.