Multicast not responding to IGMP query

[madsci1016]

I can't directly confirm this because I don't have the right wireless snooping equipment, but based on some tests i think it's a fair claim to say the ESP doesn't respond to IGMP query messages when using multicast mode.

My Christmas light display consists of a dozen ESP8266s driving pixels and dimmers in my front yard. Data is delivered via multicast from a computer on my wired network. For simplicity and traffic segregation i tried to isolate my Christmas lights onto a vLan and use layer 3 switches and routers in between my show computer, the AP and some wired light hardware. It would work, but only for a few minutes before suddenly all the ESPs in multicast mode would all stop receiving data. The few I have that use unicast would continue to work fine. Power cycling an ESP would get me another few minutes before stopping again. I can still access a web config on a dark ESP via http and ping it's normal ip address.

If i remove all the level 3 switches and swap them for dumb ones, everything works fine all night.

I can only conclude that my layer 3 switch waits until a timeout and send an IGMP query message to confirm members in a multicast group are still present on an interface. When it would get no replies, it would stop forwarding multicast data to that interface.

Firmware running on the ESP is here: https://github.com/madsci1016/ESPixelStick

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[igrr]

Which version of IGMP does your switch use?
Is there a way to reproduce this behaviour without extra equipment?
In theory, IGMP v2 should be supported by the underlying lwIP stack:
https://github.com/kadamski/esp-lwip/blob/esp8266-1.4.1/src/core/ipv4/igmp.c#L389
If it doesn't work for some reason, lwIP may be rebuilt with debug output enabled (LWIP_DEBUGF and IGMP_DEBUG), to see how queries are handled.

[madsci1016]

Well the L3 switches are responding to the IGMPv2 messages they get initially from the ESPs, so I assume they are v2 or are at least backwards compatible. You can reproduce if you have a PC, and ESP and a L3 switch in between. You might be able to test IGMP messages to an ESP without a L3 switch by handcrafting IGMP packets and looking for a response. That's outside my area of expertise.

I still haven't been able to setup a test and capture an ignored query message, but I have timed the failure. It's exactly 4:20 from power up to data blackout, which is the default Group Membership Interval according to https://tools.ietf.org/html/rfc2236 It's got to be ignoring query messages or my 2 different brands on L3 devices just don't bother sending any. But they are name (ISP) brands, so I'd would image a problem that big would be noticed.

If I disable IGMP snopping the issue goes away, but it hammers my whole network with multicast traffic.

[devyte]

@madsci1016 this issue is very old. Is it still valid with latest git?

[devyte]

@d-a-v would this be something relevant to test between lwip 1.4 and lwip2?

[bsz0206]

I am not really sure this is exactly the issue I saw but have a look at the comment on put on #1826

[d-a-v]

@bsz0206 can you please elaborate ?
With what sketch and which version of core are you triggering the crash described in #1826 ?

[bsz0206]

It is on 2.3.0. I don't know more than this as I am not the developer of the device (https://github.com/OpenGarage/OpenGarage-Firmware).

[d-a-v]

@bsz0206 Are you willing to test this and reproduce the bug with current master = latest git (which is post-2.4.0rc2) ?

[springile]

Is this issue closed ?

[bsz0206]

Yes, I don't experience it any more.

…

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[springile]

Hi

How did you fix it?

Thanks.

[springile]

I still have similar issue on using 2 networks cards in the same vlan in linux mint?

[earlephilhower]

Closing as original issue reported solved.

Yes, I don't experience it any more.