IGMP snooping not working on access switches

[dloeliger]

Hello,

We are implementing a network for AV applications, like Dante audio over IP, NDI and lighting control.

Last year, we implemented the core part and 3 access switches and this year we added quite a bunch of access switches.

Before this year's extension, we had IGMP snooping enabled on the whole network and things worked fine - all multicast traffic was flowing as expected.

The following multicast groups are used for all devices to work properly:

Group address	Port	Usage
239.255.0.0/16	4321	ATP Multicast Audio
239.69.0.0/16	5004	AES67 Multicast Audio (RTP / AVP port)
223.0.0.233	8700-8706	Dante Control
224.0.1.129-132	319, 320	PTP
224.0.0.251	5353	mDNS
224.0.0.230 – 233	8700 – 8708	Multicast Control and Monitoring
239.16x.x.x		ACN Yamaha
239.192.x.x-239.195.x.x	SDT session, dyn. Based on IP and MAC Shure
239.254.1.1	9998	Logging
239.254.3.3	9998	PTP Logging (if enabled)
239.254.44.44	9998	Logging
239.255.254.253	8427	Multicast SLP Shure/Yamaha
239.255.255.250	1900	SSDP, service discovery Shure
239.255.255.253		SLP multicast address Shure
239.255.255.255	9875	SAP (AES67 discovery)

After adding the access switches this year, we have a problems with multicast traffic reaching them from other switches. Only on the NEW switches. They are all connected over a trunk LAGG to the core switches with the same admin VLAN and allow all VLANs.

So we had to limit IGMP snooping to the core switches to re-gain normal functionality. This is a problem for access points and 100Mbps devices, we can't leave the network in this situation.

Does someone know what can be a problem for multicast traffic on Meraki switches? All switches are MS425-32, MS125-24/48.

And how on earth this problem happens only on new switches?? Is there a hardware change?

Thanks,

Daniel

[cmr]

@dloeliger are the old and new access switches all the same MS125 models?

[cmr]

And there are differences, the ms120-8p models we got a couple of months ago differ from the ones we received a year or so ago as the new ones experienced the PoE mis-location issue, but the old did not...

[dloeliger]

No, 24 and 48 ports models.

[ww]

https://community.meraki.com/t5/Switching/Multicast-Basic-s/m-p/25867#M2125

[dloeliger]

IGMP snooping querier is enabled on each VLAN where needed.

[ofelipe]

@dloeliger Sorry to revive this topic, but I'm having problems very similar to the MS120, the igmp traffic apparently doesn't flow in the LAGG between the switches, were you able to resolve this somehow?
I'm also using this for Dante, I don't know if it was a good idea lol

[dloeliger]

@ofelipe So we we found one problem, we had to unstack the core switches to have multicast work fine with igmp snooping enabled. Maybe even brake lagg also (but no more abolutely sûre about this point).