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Member
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Registered: ‎02-03-2014
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Multicast problem: UAP-AC 3.2.5: Works fine in OpenWRT Barrier Breaker

[ Edited ]

I have a UAP-AC v1 connected to the POE injector supplied with the device. I'm currently running UniFi 3.2.5 with no customizations. @UBNT-Jerry @UBNT-MikeD , perhaps my description of the problem might lead to an obvious solution?

 

Problem summary:

The UAP-AC almost always sort-of isolates wifi clients from multicast communications that happen on the LAN the AP is connected to. The AP has been factory reset, and there are no config overrides in the site config.properties file. I have tested with 3.2.5, 3.2.1, 3.1.13, and 2.4.6 and had the same result with each version. I factory reset, readopted, and "upgraded" the AP each time I changed the controller version.

 

If I connect the wireless clients to a TP-Link wireless router (configured as a bridge) connected to the same switch as the UAP-AC the problem does not occur.

 

What might I have done wrong, and what can be done to make multicast behave as expected? I've looked through the Knowledge Base and searched the forums a bit, but haven't come up with any promising solution.

 

A network diagram and detailed problem description follows:

 

Network diagram:

Wired: [server, mindy] <--> [dumb switch] <---> [dumb switch] <---> [UAP-AC, TP-Link]

Wifi: [campstove, kubuntu]

 

Server and Mindy are connected with wired ethernet. Campstove and Kubuntu are either connected to the UAP or the TP-Link, but both machines are connected to the same AP and SSID. All machines involved are in the same subnet. Kubuntu is a machine booted from a Kubuntu 14 LiveCD.

 

Detailed Problem Description:

On each machine, I install socat and run the following command:

socat UDP4-RECVFROM:1901,ip-add-membership=239.255.255.251:$MACHINE_IP,fork EXEC:'bash -c ./blah.sh'

 blah.sh is this:

printf "%s %s\\n" `date -Ins` `hostname`

 On one of the wired machines, I run the following command:

socat STDIO UDP4-DATAGRAM:239.255.255.251:1901

 When I press return, I get messages back from the socat listeners like this:

2014-10-20T17:58:48,061522701-0700 server
2014-10-20T17:58:47,833022211-0700 mindy
2014-10-20T17:58:48,065617032-0700 campstove
2014-10-21T00:58:48,132129630+0000 kubuntu

 On one of the WiFi machines connected to the UAP-AC, I run the same socat datagram generator, but I get back these messages when I press return:

2014-10-20T17:55:05,460369763-0700 campstove
2014-10-21T00:55:05,430976969+0000 kubuntu

It's like the WiFi-connected machines are in their own island when they try to talk to the LAN.

 

When I connect both of the Wifi machines to the TP-Link AP, restart the socat listener, and run the datagram generator on one of the Wifi-connected machines, I get these messages when I press return:

2014-10-20T17:58:48,534873897-0700 server
2014-10-20T17:58:48,305108774-0700 mindy
2014-10-20T17:58:48,539899075-0700 campstove
2014-10-21T00:58:48,615774097+0000 kubuntu

 I also get the full set of messages when I walk over to the wired machines' datagram generator and press return.

 

Now, remember how I said that the UAP-AC almost always isolated the WiFi clients? If I wait for some random period of time, when I run the WiFi datagram generator, I'll get messages from all listeners on the LAN. BUT, when I run the wired datagram generator, I only get messages from the wired machines. If I restart the listeners on the WiFi machines, then the WiFi machines are back in their little island and only the wired machines can see them.

 

Another interesting note: For a while, I had the listener listen on port 1900; the same port as SSDP. Even though the listeners weren't listening on the SSDP multicast address (239.255.255.250), machines connected to the UAP-AC would reply to multicast SSDP discovery requests with the date and their hostname. Machines on the wired network never replied to SSDP discovery requests.

 

Any idea what's going wrong? How can I fix this? What more information should I supply?

Member
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Re: Multicast problem: UAP-AC 3.2.5: Works fine in OpenWRT Barrier Breaker

I guess I can supply the device system.cfg file, no? Usernames, passwords, and SSIDs have been redacted, but otherwise this file is unedited.

Attachment
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Re: Multicast problem: UAP-AC 3.2.5: Works fine in OpenWRT Barrier Breaker

[ Edited ]

Did you try disabling IGMP snooping? If not, see THIS article.

 

Thanks,
Mike

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Member
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Re: Multicast problem: UAP-AC 3.2.5: Works fine in OpenWRT Barrier Breaker

[ Edited ]

Gah. How did I overlook IGMP snooping?

 

Anyway, I disabled IGMP snooping on all of my SSIDs. My wireless clients are still isolated. After I disabled IGMP snooping I disabled multcast filtering. The wireless clients are still isolated.

 

A diff between the current UAP-AC config and the one that's attached to comment #2 is attached.

 

EDIT: To eliminate confusion, note that six SSIDs are configured on this UAP-AC, but the wireless clients are all connected to SSID #1; whose settings begin with "aaa.1" or "wireless.1" in the config file.

Member
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Solutions: 4

Re: Multicast problem: UAP-AC 3.2.5: Works fine in OpenWRT Barrier Breaker

[ Edited ]

I did some more testing:

 

I plugged the TP-Link AP into the bridged ethernet port on the UAP-AC, then connected my wireless clients to the TP-Link. The clients were not isolated in any way, so this is not some crazy bridging issue.

 

I deactivated Multicast snooping and Multicast/broadcast filters and re-tried my multicast test with 3.2.5, 3.2.1, 3.1.13, and 2.4.6. The client sort-of isolation problem was present in every one of those Unifi versions. I double-checked the device config to verify that wireless.N.mcast.enhance=0 was present in each config file before performing the test.

 

I discovered that I can control the directionality of the multicast isolation:

If I disconnect and reassociate with the AP, the wireless client will get messages from all wired clients and from itself. However, the wired clients will only get messages from other wired clients. If I then restart the multicast listener on the wireless client, the wireless client only receives messages from itself, but wired clients receive messages from other wired clients, as well as the wireless client.

 

This is probably obvious, but packet captures indicate that stopping the multicast listener on the wireless client sends a multicast leave message, then a restart of the listener sends a multicast join message. It smells like there's still some smart multicast management code running on the UAP.

 

Do I (somehow) have a bum unit? Can anyone at Ubiquiti (or any forumgoer with an hour to kill) reproduce this problem in the lab?

 

Thanks!

New Member
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Registered: ‎12-09-2014
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Re: Multicast problem: UAP-AC 3.2.5: Works fine in OpenWRT Barrier Breaker

Having this exact same issue with every UAP-AC we've deployed. It does not appear to be an issue with any other class of UniFi APs. Disabling IGMP Snooping and Multicast filtering via config.properties does not correct the issue. Here is a related thread I've found:

 

http://community.ubnt.com/t5/EdgeMAX/ERL-UniFi-problems/td-p/643407

 

We've experience the exact issue in the above thread with the exact same use case. It appears that the UAP-ACs do not properly forward multicast traffic between the LAN and WLAN.

 

Sean

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Re: Multicast problem: UAP-AC 3.2.5: Works fine in OpenWRT Barrier Breaker

Hi guys,

 

Thanks for the information. I've opened a ticket for this issue. Will report back.

 

Cheers,

Mike

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Re: Multicast problem: UAP-AC 3.2.5: Works fine in OpenWRT Barrier Breaker

hi @kl, I am suspecting that maybe this is cause by multicast enhancement feature which converts multicast to unicast. Could you try these:

 

  1. ssh into the UAP-AC
  2. execute below commands
  • wl -i eth1 wmf_ucast_igmp 0
    wl -i eth2 wmf_ucast_igmp 0
    wl -i wl0.1 wmf_ucast_igmp 0
    wl -i wl0.2 wmf_ucast_igmp 0
    wl -i wl1.1 wmf_ucast_igmp 0
    wl -i wl1.2 wmf_ucast_igmp 0

    wl -i eth1 wmf_ucast_upnp 0
    wl -i eth2 wmf_ucast_upnp 0
    wl -i wl0.1 wmf_ucast_upnp 0
    wl -i wl0.2 wmf_ucast_upnp 0
    wl -i wl1.1 wmf_ucast_upnp 0
    wl -i wl1.2 wmf_ucast_upnp 0

ethX and wlX.X are used for indicating different wlan interfaces.  Redo your tests after executing above. Note that these will be gone if UAP-AC rebooted. For now, I am only trying to determine if this is indeed the cause. Thanks.

Member
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Re: Multicast problem: UAP-AC 3.2.5: Works fine in OpenWRT Barrier Breaker

Executing those commands didn't resolve the problem. My wireless clients are still either in an island, or don't reply to wired clients, as described above.

 

Did you find that this worked for you in the lab? If so, were you using a UAP-AC v2? I'm using a v1 that has really disappointing 802.11ac performance.

New Member
Posts: 1
Registered: ‎02-02-2015

Re: Multicast problem: UAP-AC 3.2.5: Works fine in OpenWRT Barrier Breaker

Hi I am curious if any update on this problem as I am wanting to install a Control4 home automation system and they currently recommend not using the Ubiquiti AC access points due to this problem which causes issues with their system.

The older access points work but I would rather have AC if the multicast bug can be fixed.
Previous Employee
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Re: Multicast problem: UAP-AC 3.2.5: Works fine in OpenWRT Barrier Breaker

We believe we are now able to reproduce the multicast issue on UAP-AC. The ticket based on this thread has been escalated and has a dedicated developer investigating the issue.  Will update. Thanks.

New Member
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Registered: ‎05-11-2014

Re: Multicast problem: UAP-AC 3.2.5: Works fine in OpenWRT Barrier Breaker

Similarly, we've just purchased a bunch of AC v2 access points and are having trouble using Airplay between APs, presumably due to the multicast filtering feature.

 

An update would be greatly appreciated.

Member
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Re: Multicast problem: UAP-AC 3.2.5: Works fine in OpenWRT Barrier Breaker

 Hey, OP here.

 

Is there any progress to report? I hear that Broadcom can be really difficult to work with if you're anything smaller than a megacorp.

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Re: Multicast problem: UAP-AC 3.2.5: Works fine in OpenWRT Barrier Breaker


kl wrote: Is there any progress to report? I hear that Broadcom can be really difficult to work with if you're anything smaller than a megacorp.

It appears a fix was made several weeks ago. I would expect it to be included in the next release.

 

Cheers,

Mike

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Re: Multicast problem: UAP-AC 3.2.5: Works fine in OpenWRT Barrier Breaker

That's good to hear! Any idea what the version number of the release that contains the fix will be (or is) and where/how to get it?

 

Thanks!

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Re: Multicast problem: UAP-AC 3.2.5: Works fine in OpenWRT Barrier Breaker

@UBNT-MikeD

 

Hey. OP here, checking in again to see if you know the Unifi version that will -or does- contain the fix for the multicast bug that I and others reported.

 

Thanks.

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Re: Multicast problem: UAP-AC 3.2.5: Works fine in OpenWRT Barrier Breaker


kl wrote:

@UBNT-MikeD

 

Hey. OP here, checking in again to see if you know the Unifi version that will -or does- contain the fix for the multicast bug that I and others reported.

 

Thanks.


I want to say it's resolved in 3.2.11/4.6.4, but I can't confirm. Can't access trac right now, seem to be having VPN issues while tethered..

 

If you wish to try the firmware, you can grab it from HERE. If you wish to just flash the UAPs, without changing the controller, see the steps I've written HERE. I haven't added 3.2.11 to the table yet, just in case that isn't the final version number (as that release is in public testing right now).

 

Cheers,

Mike

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Re: Multicast problem: UAP-AC 3.2.5: Works fine in OpenWRT Barrier Breaker

[ Edited ]

Hey. Just a heads up: I just pulled down Unifi 4.6.4 and installed it on my troublesome AP. If this was the version that was supposed to fix my problem, then know that it does *not* fix my problem.

 

Edit: I instructed Unifi to forget and factory reset my AP after I upgraded the firmware. My problem was not fixed. I then modified system.cfg as mentioned in post #4 in this thread and reprovisioned the AP. My problem is still not fixed.

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Re: Multicast problem: UAP-AC 3.2.5: Works fine in OpenWRT Barrier Breaker

Thanks for the prompt response/test. I'll double check trac when I'm home, but that probably won't be until tomorrow.

Cheers,
Mike
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Re: Multicast problem: UAP-AC 3.2.5: Works fine in OpenWRT Barrier Breaker

Yes, there's a ticket in trac for this. We also have a fix for this in next release. Please help us try 3.2.11 and verify if this still exists or not.

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