Hi, latest....
Cisco TAC asked us to disable/re-eanble PIM on the switch, this worked multicast started working for our Server. Multicast started to flow.
Something very weird in my debugs, I can see multicast flowing on the switch port but not any IGMP join requests, so I asked tour server team to send out a IGMP request for another group, the IGMP membership request was seen for new group but no replies, multicast for this group failed, I then disabled/enabled PIM, multicast started flowing for the new multicast group....still with TAC.
Below are my tests:
So PIM up & IGMP Snooping up on vlan x – Multicast is seem on the server port without IGMP requests
Disabling PIM (no ip pim sparse-mode) stops the multicast
Starting it again starts the multicast flowing. Several times I disabled PIM and the server port stopped seeing multicast, enabled it and it flows again.
So I left it disabled
Then
Disabling IGMP (vlan config x , no ip igmp snooping) starts the multicast arriving again.
Enable IGMP and the multicast stops
Again I stopped and started IGMP snooping on vlan 116 several times and whenits disable multicast arrived and when enabled the multicast stops arriving.
If you leave IGMP snooping enabled then PIM being enabled/disabled on vlan x does exactly what it did previously
But if you leave IGMP snooping disabled (Multicast flowing ) you can enable PIM on vlan x and multicast is still flowing you can then re-enable IGMP snooping and the multicast stops
Both states show PIM up & IGMP Snooping up on vlan x but multicast has stopped - I suspect at this point even if the serve requests multicast it would not arrive at the port which i might test
This is exactly the same state as at the beginning but Multicast has stopped flowing
But there is a warning
(config-if)# ip pim sparse-mode
Warning: PIM is not supported on VxLAN extended VLAN
Warning: Please ensure igmp snooping is enabled on the corresponding vlan, using the command 'show ip igmp snooping vlan <x>'. IGMP snooping MUST be enabled for correct forwarding functionality. Following this please disable and re-enable the current pim configuration.
If you disable and re-enable PIM as asked multicast beings flowing again.
I have left the switch with the multicast still being received but it looks like snooping isn’t working. Devices should only get multicast they request and not constantly receive the stuff.
Further thoughts are
1) With PIM enabled & IGMP snooping enable multicast flows without IGMP requests, when you disable PIM the multicast stops.
Question: If the server request multicast for a certain groups will the multicast arrive ?
If Yes then is it only the request groups that arrive or all multicast groups ?
Also If Yes does the multicast stop when the requests for it stop or a IGMP leave is sent?
2) In the funny state with PIM enabled & IGMP snooping enabled but Multicast is not flowing to the server port.
Question: I If the server request multicast for a certain groups will the multicast arrive ?
If Yes then is it only the request groups that arrive or all multicast groups ?
Also If Yes does the multicast stop when the requests for it stop or a IGMP leave is sent?
