Cisco (Codian) MCU to C\SX connection problem.

[afadeyev1]

Hi, We have around 50 remote sites with 99% of them connected via MPLS with properly implemented QOS. All point to point and multipoint calls works fine with exception of 2 sites, that connected via GRE or IPSEC tunnels without QOS. The interesting moment is that point to point calls from those 2 sites to other sites works fine, but once you place the call to MCU's (5320, 4501, 4205) video and audio is dramatically worse. I tried different codecs, jabber clients - the problem is consistent. I suspect that MCU does not have one of the advanced error recovery algoritms that codecs have, but cannot find direct evidence of it. Would appreciate any ideas.

[Martin Koch]

I would have to check but from how I recall it there is only an experimental setting regards rate adoption which

is not on by default, so that might not be the case here.

Please always say a bit more about the deployment and the possible traffic flow (adding a sketch is helpful).

Is it just in a specific direction, like to the endpoint or in both directions?

If you know that there is not enough bandwidth, did you adjust the max bandwidth settings on the endpoint

and/or via a vcs (links/pipes)

What is the bandwidth and the MTU on the GRE link?

Also do not forget that the media traffic might flow completely different when using the MCU instead of

calling an other endpoint (especially if its a non-traversal call)

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[afadeyev1]

When you talking about the badwidth on non-guaraneed link it's always a gamble. But I don't think it's the bandwidth.

One site has 20 up/ 5 down and another one 50/50. I tried dropping call rate to 768 and still got green distortion all over the screen. There was no other traffic at the time.

The problem is visible in both directions. Initially I was blaming tunnel (MTU size, router performance...) but I did few tests: placed call via my expressway. All traffic went directly from codec to expressway without the tunnel - same thing.

I connected test system to the same switch as MCU to duplicate the traffic flow. But regardless of what I tryed  - point to point always good. Connection between MCU and endpoint via non QOS connection is worse. There is only ocasional packet loss and jitter is average.

[Wayne DeNardi]

What software version are you running on your MCU?  I can vaguely recall someone having a similar issue in these forums previously which they solved by upgrading to a recent release.

Another thing that can cause issues which you may have in your network are WAN optimization devices - make sure to bypass these for any of your VC traffic.

Wayne
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[afadeyev1]

The software on 5320 is 4.4(3.57), 4501 - 4.4 (3.49).

As I said before - I tried placing a call via Expressway - same thing. So, I don't thing network infrustructure is to blame.

I mean there is some packet loss and jitter, but why is direct call so much better than call via MCU?

[Wayne DeNardi]

Can you post the settings for your MCU conference and any of the settings for the MCU itself - so we can see if there's anything that looks odd in the configuration - ie, are you limiting the bandwidth on it, or the codecs, video packet size, etc?

Wayne
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[afadeyev1]

Hi Wayne,

Here is 2 screenshots with General and conference settings.

The MCU port mode is HD.

I'm  limiting the bandwidth on the VCS (per site basis). About 60% of my  systems are set to maximum bandwidth (we have a fat pipe at the main  locations). The 2 locations, that are having problems set to 768 kbps  and unlimited.

I tried changing the "per call" badwidth to 512 kbps, but it did not help.

Thank you.

[Wayne DeNardi]

About the only setting that's different on yours to mine, that could possibly be affecting the image, is the "Motion / sharpness tradeoff" setting.  I do also vaguely recall an issue with some of the codecs and the "Sharpness" setting - and things working better when set to "Motion" - mine's set to "Balanced". 

I also allow H.261 to and from the MCU - but that's not likely to be your issue.  (And I'm in the PAL part of the world, instead of NTSC - not that that should matter at all).

Otherwise, the settings are pretty identitical. 

Wayne
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[afadeyev1]

I tried playng with Motion\Sharpness\Balanced, but can't see a difference. Left it at "Balanced" on both MCU's  - will see how it goes. Thank you.