IGMP V2

[ngidwani09]

Question 1

When a multicast is streaming from an interface will the switch (Cisco Nexus 9372PX) send periodic IGMP membership queries to that interface, or is multicast streaming on the interface sufficient to maintain multicast group membership without a periodic IGMP membership queries from the switch?

Question 2

If a device is sending packets on an interface on a regular basis such that the switch can see the source IP address and MAC addresses associated, do ARP requests still occur periodically to that interface or does ARP refresh the association based on the outgoing packets?  (This would seem like a logical thing to do.)

[Jean-Francois Dube]

Greetings ngidwani09,

Q1: IGMP querier will do periodic queries no matter if there is multicast traffic or not. One important concept for multicast is the separation of forwarding and signaling.

Q2: ARP request will occur after an ARP entry expires in the table. MAC learning does keep going for as long as there is traffic. Remember a switch operates at layer 2 and does not perform lookup at layer 3. It cannot learn IP addresses that way.

Hope this helps.

Cheers,

JF

[ngidwani09]

Thank you for the response.

I had my preservations and after reading and viewing all prevalent IGMP information from the numerous sources that neither were permissible.