Multicast not working via wireless

I have a modemrouter (o2-6431 and EasyBox904) running LEDE 17.01.4. I want to connect a Media-Receiver for IPTV, most channel there are delivered with multicast, some with unicast. I have bridged wired-eth and wireless to a br-lan-interface (lan). I have installed/configured igmpproxy. If I connect the receiver wired, everything works like a charm, but I want to connect it wireless. The receiver has no wireless-iface. To achive that, I set up a Raspberry/OrangePi as a repeater or media-converter wired/wireless. This device has a wlan and a wired-eth-interface. I installed also Lede 17.01.4 on this device and bridged both interfaces with via pseudobridge (relayd). Unicast-channels working with this setup without problem, but no multicast. The firewall on this device is wide open or disabled. What could be the reason for that? Could it be a relayd issue? Or is there another setup-possible, maybe some kind of layer2-passthrough?. I heard about bandwidth-problems with wireless-multicast, but there seem to be no multicast-traffic at all. As the wired connection is working, it shouldn't be also no firewall/igmpproxy configuration-issue on the router

Multicast is not recommended over WiFi.

Most IPTV providers warn you not to use WIFI for streaming.

You're going to need a Ethernet cable.

An alternative is using a homeplug AV device which will work well if you can't run a Ethernet cable all the way back to your router or switch.

1 Like

I read those stories, no one of them could substantiated explain why it shouldn't work generally, maybe at least with some stutter or pixel when the wifi-connection isn't perfect. But on the other side, there are also many success-stories of people got it working. People also reporting about problems with powerline

You will generally have some dedgregation.

It will; but as you noted, you may experience serious "stutter." This is due to UDP being stateless. If the packets are received out of order or not at all, you loose the frame and audio.

I know there are some degregation over wired, but the wireless connection is very stable and I get real transfer-rates of at least 70MBit with iperf3, so it should be possible to get decent results for a stream of 7Mbit. I also mentioned, that I don't get any multicast-traffic at all

Common remedies to multicast over wifi problems

One common solution to the multicast over wifi problem is to convert the multicast traffic into unicast. This is often referred to as multicast to unicast (MC2UC). Converting the packets to unicast is beneficial because unicast packets are acknowledged and retransmitted as needed to prevent as much loss. The Access Points (AP) is also able to provide rate limiting as needed. The drawback with this approach is that the benefit of using multicast is defeated.

Using 802.11n helps provide a more reliable and higher level of signal-to-noise ratio in a wifi environment over which multicast (broadcast) packets can be sent. This can provide higher throughput and reliability but the broadcast limitations remain.

Did you enable IGMP Snooping on any VLAN or switch port?

tried it with both, no difference

echo "0/1" > /sys/devices/virtual/net/br-lan/bridge/multicast_snooping

and if this an issue, why should there be a difference between wired and wireless

as mbo2o stated, if I convert it to unicast with udpxy on the router, no problem with multicast streams, if I use an Android-TV-Box with a configurable IPTV-Player. Unfortunatly the media-receiver has proprietary-SW and I cannot change the URL to the udpxy

Because, if you enabled it on the port, it wouldn't be enabled on wireless (VLAN bridge). And to be clear, some devices allow you to set this on the switch.

Since you have the same behavior in both instances, it should be OK.

Correct, most devices looking for multicast packets, expect them to be UDP. There's a thread on this forum where posters had the same issues converting to unicast...I think this thread, beginning around post #53 may be helpful:

Thanks IIeachii, your linked threads gives me some hints to investigate further, unfortunately I didn't find that thread before, I only found this similar one, which didn't give me a real clue

I've got it working now, I omitted the forward-rule in the firewall that already is set by the igmpproxy start-script. Unfortunatly I have, like already predicted, horrible stutter, so it's unusable.
My next approach is, as udpxy works perfect, to send the stream via wireless-unicast to the repeater-device (OrangePI), and convert it there back to multicast and also prepare the request for udpxy, so it's transparent to the media-receiver. My question: Is there some SW opposite udpxy?