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Upstream Multicast on WLC


Dear Experts,

may i request your advice.

Following is the scenario:

Imagine a subway tunnel.

The trains, going with a maximum speed of 23 Meters per second are wireless clients with static IP configuration.

Connectivity and roaming work excellent

On the ceiling are mounted 40 Air-AP1242 (future 200) with 5GHz Radio shut.

A WLC 4400 series WLC with 7. - Software ist controlling these APs.

The trains have surveillance cameras installed.

These deliver up to 6 IP- Multicaststreams upstream each to the Controller.

I refer to this traffic pattern as "Upstream Multicast".

I know that the intended Multicast behaviour with WLCs is downstream which is Multicast source is on the wired side and wireless clients are optional Multicast recievers.

Now here comes the tricky part.

Whatever i try, the controller is reflecting the videostreams coming from one or multiple trains simultaneously either back into every LWAPP/ CAPWAPP - Tunnel (Setting "Unicast) or delivers it to a Multicast - Address (Setting Multicast).

I would like to prohibit this "reflection" as the only intended reciever of this video streams is as you might fancy the security personnel on the wired side in the Subway Controll Cennter.

Did i overlook some features in the 7 Software?

I had a closer look to implemented "solutions" from competing vendors. These were pure boasts. They had no idea what they were doing.

I would really like to stick to the Cisco solution.

So are there any ideas out there?

Many thanks in advance


11 Replies 11

Cisco Employee
Cisco Employee

Hello Hermann,

my 2 cents on this ;o)

as i understand you want to avoid sending the stream to all AP's joined to WLC , right?

can you please check about the multicast stream feature that has been added into WLC 7.0

hope this helps.

Kind regards



please rate answers that you find useful.

Nicolas Darchis
Cisco Employee
Cisco Employee

I'm sorry to contradict a little bit Talal, but the VideoStream feature on 7.0 is mainly intended when wireless clients are the mutlicast receivers.

Here, I would actually wonder if you have IGMP snooping enabled Hermann ? On the WLC I mean.



Hello Talal, hello Nicolas,

thank you both for your kind answers.

@ Talal

After reading the excerpt of the config guide you mentioned in your post i am sorry to say that Nicolas seems to be right as the configuration steps covered imply wireless clients as Multicast recievers. This paper deals with the task to improve multicast to this clients. My wireless Clients (more precisely put - the surveillance cameras in the subwaytrains) are the multicast sources.

@ Nicolas

Yes. IGMP snooping is enabled.

The status of the system in this very moment is the following:

Wireless Client sends 4 surveillance camera video streams via AP 1242 via CAPWAP - Tunnel to WLC 4404 Software 7.0.98.

as intended.

WLC copies Multicast streams to the VLAN to which the WLAN is mapped.

as intended.

WLC copies Multicast stream to configured Multicast Group which is routed via PIM- sparse mode (HP - Procurve Multilayer Switches) and thus reaches each Ap 1242.

not intended.

AP does not forward Multicast stream on the Wireless Interface.

I am very pleased with this.

But i really would like to stop the spreading of the Multicast back to the APs as there will never be a Wlan - Client which is in need to get this Video streams.

Sorry if i didn't put my intentions clear enough.

Maybe there are any other ideas.

By the way: any ACLs on the WLC or cutting down the Multicast forwarding on the HP switches kills WLC <-> AP connectivity.

Again thank you all for reading and partially giving your 4  2 or 1 cent ;-)

kind regards


Hi h-zenk,

  Did you find a solution for this ? I also have a situation of upstream multicast with cameras connecting through a WGB to a WLC infrastructure and streaming multicast video (cameras as sources). I am experiencing video quality issues.



Hello Joe,

we stopped investigating into this issue as the underlying Multicast network easily handles the surplus multicast streams which are mirrored back to the Access Points. Second the controller load is not to high.

May I say that i have a "feeling" that your problem is in the "air".

Is your WGB moving?

Do your Access Points forward the reflected multicasts into the SSID?

What about your retry counters on the WGB?

Kind regards


Hi Zenk,

Are these camera source multicast traffic to same group address or individual camera stream is having unique group address ?


Hi Rasika

there have been a maximum of 24 individual streams if i remember right.



Hi Hermann,

Please correct me if my understading is wrong.

Camera1  Stream to group - (for example)

Camera2  Stream to group -


Issue is WLC is sending copy of each group traffic to all APs  even though there is no wireless client required/join to these group addresses. Is that correct ?

Where is the receivers for this streaming traffic ? Are they purely on your wired network ?

This is an interesting issue & I am trying to understand it


Hi Rasika

you are understanding correctly.

Up to 24 group addresses used,

streams are delivered solely to the wire.

If you read the first two posts of mine thoroughly you might get a good picture of the situation.



Hi Hermann,

Do a test when train is not moving (when it stopped) & see traffic stream coming from one camera is reflected to all APs ? If not all what APs get this.

Since train is moving fast, when AP2 get multicast stream from a camera, still AP1 may have information (not aged-out) already got from the same camera few seconds earlier, not sure though.

If you do this test, we know whether issues is due to moving nature (mobility) or purly the way WLC treat upstream multicast traffic.



Hi Rasika,

we did all the tests you mentioned.

Under all circumstances the Multicaststreams have been reflected in EVERY CAPWAP - tunnel.

So the only thing i would have needed (2 years ago) would have been a command on the controller.

Something like "do not multiplex multicast which is originating from your APs".

When asking for that, we have been told "maybe in an upcoming version".

As customer is satisfied with the system and due to harsh restrictions on state budget in this country the problem is more or less cosmetic, and i am the single person who feels uncomfortable with it.

Kind regards


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