Problems with wireless Multicast Stream in AV Installation

  • 0
  • 1
  • Question
  • Updated 3 years ago
  • Answered
Hi Community,
I have a problem running a AV streaming device in a customers wireless network. The device is the following: https://www.wolfvision.com/vsolution/index.php/en/presentation-systems/cynap/overview
The network setup is as follows:
2 pcs. Summit X460-48p
6 pcs. AP3825i
1 pcs. V2110 Hyper-V Edition

Streaming through the wired network is no problem either multi- nor unicast has any issues. Streaming through the wireless network does only work with unicast streams. At the moment I activate the multicast group 225.0.0.1 I get a very bad picture and a very slow connection speed to the wireless network. It makes no difference if I use a laptop, iPhone or iPad (Airplay works fine). I have activated multicast bridging for the VNS and added 0.0.0.0/0 All Multicast.

Within the wireless network I have 25 participans 80% smart devices 20% laptops so this should be no problem for the above mentioned network setup.

I have read through the articels about multicasting and I can ́t find a way to get it work.

By the way, connecting the wolfvision device to a standalone AP with 811.2n everything works fine. So for me it looks like I have screwed up something with the multicast handling.

Thanks for your help!

Marco
Photo of Marco Pfiffer

Marco Pfiffer

  • 414 Points 250 badge 2x thumb

Posted 3 years ago

  • 0
  • 1
Photo of Ostrovsky, Yury

Ostrovsky, Yury, Employee

  • 3,050 Points 3k badge 2x thumb
Hi Marco. First of all, make sure you set DTIM to 1, since multicast packet will be sent every DTIM period. Second - multicast by default using Minimum basic rate , so try to increase it up to 24 Mbps. Thats the first step.
There are also some multicast optimization settings, but that you can dtart playing with after you fix first two things I mentioned. Btw, what is the video stream bitrate you using?
Photo of Marco Pfiffer

Marco Pfiffer

  • 414 Points 250 badge 2x thumb
Hi Yury, I have tried your solutions and it improved the streams. I also played around with the mutlicast optimization settings you and Ron mentioned but I still get no satisfying stream especially when I try to stream to two or more endpoints on the same AP.
Photo of Ostrovsky, Yury

Ostrovsky, Yury, Employee

  • 3,050 Points 3k badge 2x thumb
Well, if you are not using mulicast-to-unicast conversion, there should be not match difference between the number of endpoints, the video stream should be only one, right? The end points are in the same subnet, on the same SSID? On your wired network, make sure you do not using any dynamic multicast routing (PIM,DVRP) between VLANS.

The conversion will help when the number of clients is not high , becouse each packet goes with much higher speed then multicast -instead of MBR its using full data rate, but at the same time the number of packets multiplying to the number of clients.
Photo of Ostrovsky, Yury

Ostrovsky, Yury, Employee

  • 3,050 Points 3k badge 2x thumb
I would also recommend to open a case with GTAC, include your configuration and the file sample . You can share the case # here, so probably we can ask our QA to run the file and see if there any problem . 
Photo of Jarek

Jarek

  • 2,398 Points 2k badge 2x thumb
Hello All,

I'm not a big fan of multicast stream via wireless, but...
Marco you wrote that you have a group 225.0.0.1.

As we know (or nor not :) )  multicast  has address overlap 32:1.
In this case we have group 225.0.0.1 and this is the same as 224.0.0.1.

Old school says that we should avoid class  224.0.0.0/24,
(address like X.0.0.Y and X.128.0.Y,)
because this is groups are copied to CPU.

Maybe this is the issue ? Maybe stream is soft switched?


--
Jarek
Photo of Marco Pfiffer

Marco Pfiffer

  • 414 Points 250 badge 2x thumb
Hi Yury,
thank you for your reply!
I will set the DTIM and increase the basic rate.
The stream is between 7 and 13 Mbit for a 1080p video. It depends on the software and the devices used to stream.
I can make the changes to the controller on monday, latest on tuesday next week.
Photo of Ronald Dvorak

Ronald Dvorak, Embassador

  • 51,328 Points 50k badge 2x thumb
Keep in mind that changing the min basic rate from i.e. 6mb to 24mb will reduce the coverage area / cell size of the APs.
That is OK if you've a very good / high density AP deploymnet but not very good if the site survey wasn't done with that value.

Might be that this will help - never tried it..
https://gtacknowledge.extremenetworks.com/articles/Q_A/What-does-Multicast-to-Unicast-feature-in-Ide...

-Ron
Photo of Marco Pfiffer

Marco Pfiffer

  • 414 Points 250 badge 2x thumb
Hi Ron,
thank you for the information. It is a small and quite high density installation but I will keep in mind. Thank ́s for the link maybe this will help also. I ́ll kepp you guys updated as I am visiting the customer tomorrow.
Photo of Marco Pfiffer

Marco Pfiffer

  • 414 Points 250 badge 2x thumb
Hi guys, I have tried everything you wrote in your posts above. Unfortunately there was nothing that helped to solve the problem. I have opened a GTAC case #01200662 now. I will keep you up to date.