A network administrator sets up two aggregation layer AOS-CX switches in a VSX pair. The switches have layer-2 VSX LAGS to access layer switches. The VSX pair has IGMP configured on the layer-3 VLAN interfaces serving the access layer switches.
What is correct regarding how the VSX pair will interact with multicast traffic and messages?
In a VSX configuration, each VSX node independently learns any IGMP join or leave messages received from downstream switches. Join and leave messages are always forwarded across the ISL link between the VSX aggregate switches to ensure consistent multicast forwarding. This ensures that both switches in the VSX pair are aware of the multicast group memberships from the downstream switches, even if a join or leave message is received by only one of the VSX switches directly.
Each VSX node individually learns any JOIN/LEAVE message received from a downstream VSX LAG. For example: Agg-1 learns on downlink from SW1, whereas Agg-2 learns on the ISL as the ISL is always included as a forwarding port for IGMP, as shown in the following figure.
Not B : Multicast traffic to these IGMP groups is pruned/forwarded based on the INDIVIDUAL IGMP group database on each VSX node https://www.arubanetworks.com/techdocs/AOS-CX/10.07/PDF/5200-7888.pdf Answer is C n Each VSX node individually learns any JOIN/LEAVE message received from a downstream VSX LAG. For example: Agg-1 learns on downlink from SW1, whereas Agg-2 learns on the ISL as the ISL is always included as a forwarding port for IGMP, as shown in the following figure.
ISL is always included as a forwarding port for IGMP
Each VSX node individually learns any JOIN/LEAVE message received from a downstream VSX LAG. For example: Agg-1 learns on downlink from SW1, whereas Agg-2 learns on the ISL as the ISL is always included as a forwarding port
IGMP snooping VSX switches can be configured for IGMP snooping on downstream VLANs facing the access switches. When enabled, the IGMP group database is independently constructed on each VSX switch. Multicast traffic to these groups is appropriately pruned/optimized. Each VSX switch has an identical IGMP group database: Each VSX node individually learns any JOIN/LEAVE message received from a downstream VSX LAG. For example: Agg-1 learns on downlink from SW1, whereas Agg-2 learns on the ISL as the ISL is always included as a forwarding port for IGMP, as shown in the following figure. The VSX IGMP process translates the received IGMP from the ISL into an IGMP join message from the VSX LAG. Multicast traffic to these IGMP groups is pruned/forwarded based on the individual IGMP group database on each VSX node. ISLP does not synchronize IGMP groups between VSX peers. The IGMP database construction is a data-plane based process. If a VSX node reboots, it must relearn all the IGMP groups. The VSX switch floods multicast traffic within the VLANs that have active physical ports being forwarded. It then sends an All Hosts Query message. When the VSX node receives all join messages, it relearns and recreates the IGMP groups database.
Page 569 Study Guide: Both switches hear JOIN/LEAVE messages they receive from the downstream VSX LAGs because the ISL is always included as a forwarding port for IGMP. [Aruba Networks]
Correct B
Should be C not B typo