Posted: Sun Dec 04, 2022 20:25 Post subject: Multicast across interfaces slow and sometimes failing
Hi all,
I've tried to search the board and the Internet for answers, but come up without any good solution to my problem, so I'm hoping someone can help me out. I have a D-link DIR-880L (A1) with a Broadcom ARM, using new firmware (50963), but I have problems using my sound system, as well as connecting to my printer. They both use multicast, and the main problem arises when I have a device on one network, say phone on 2.4 GHz, trying to connect to a device on the other network, say sound system on 5 GHz.
For the sound system - Denon Heos - it works _most_ of time, but there are delays/slowness in response and sometime the message clearly does not reach the recipient. If I'm one the same network, it works ok, but it's not fantastic either.
I also have a printer - Epson XP-235 - that uses the 2.4 GHz, and if my phone is on 5 GHz I cannot find or use it.
- Multicast to Unicast is enabled
- Bridged configuration for both interfaces, as I want same subnet
- IGMP snooping is turned on for br0 (the default and only one I use)
- mDns is enabled, with reflector
What more can I do? I know that I can Unbridge the interfaces and use the "Multicast Forwarding" setting, but I do want them on the same subnet, and I also don't know if that would solve anything.
Igmpproxy doesn't seem like as solution as that's a one way ticket only, but I need multicast flowing both ways.
I apologise if I've overlooked something obvious here, but if someone can give some pointers or insights I would be grateful. Using stock firmware I never had these issues, which is why I hope there is some kind of solution out there. Thanks!
You don’t need any IGMP proxy or mDNS responder at all. If both Wi-Fi radios are connected to the same bridge, multicast traffic will pass unless explicitly disabled.
Turn all the other stuff off, as it’s meant to proxy between two or more subnets / bridges, not across a single subnet / bridge, or you want to enable filtering. The individual devices will take care of their own multicast traffic, if the router is left at the defaults. With only two to three devices, there is little need to cull and redistribute the IGMP channels and more likely that the snooping will drop frames.
IGMP snooping also doesn’t work with IPv6, and a lot of devices set up link-local v6 addresses for mDNS and multicast, now.
What you can try is decreasing the beacon interval in each radio’s advanced settings to cut down on frame retransmissions.
True, I don't need mDNS for general multicast, but I do use Spotify Connect (and Chromecast) which requires it, sorry for not being clear there. Igmp proxy is not enabled, like I wrote. As for Multicast to Unicast, is that only across networks? It couldn't hurt to have it anyways I guess? And to be honest, I have tried both with and without. Same with IGMP snooping.
The reason for enabling all of them, or some of them, is that I don't see it working well with "defaults", which is why I'm asking the question. I did read somewhere on the forum that multicast in a bridge has problems since it only goes to one interface, not sure if that's correct or not.
Right now though, even with a factory reset router (aside from setting SSID, security etc.), it doesn't work well. That's why I'm asking. Within an interface, it works ok, across 2.4 and 5, it does not work well.
I'll try the beacon setting, to lower it (right now it's at default 100) and see if helps. Thanks for the suggestion!
