Issue on two 2811 routers with 7 BRI for CUCM

[tboucheau]

Hi,

I'm having trouble with 2811 routers hosting 7 BRI (4 on the first and 3 on the second). When I reach 4 simultaneous calls, the voice quality is very poor : delay, distortion...

I though of DSP issue but I'm not sure of what is configured... My provider do not let me access the configuration... What should I do to debug this. The BRI has been reviewed by the PTT and only 2 are dysfuncts. So making 4 calls simultaneously shouldn't be a problem.

Thanks for your responses... if you have...

[troullier00]

If your voice quality is suffering I would suspect a QOS issue. Could you post more information about the setup and the configuration.

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[tboucheau]

No it's definitly not in QoS as we already have installes several sites. It's the only site with 7 BRI with no additionnal PVDm modules. I'm thinking of an hardware limitation as it appears only on the 4th call done simultaneously.

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[troullier00]

What PVDM module is installed, can you post a show inventory.

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[tboucheau]

There's no pvdm module installed. The only DSPs availlable are those built-in on the network module (i don't know the hardware exactly as my provider is not fully transparent.)

Should I have pvdm modules to make 4 simultaneous calls on BRI ?

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[paolo bevilacqua]

I think you must complain to your "not fully transparent" provider and stop paying bills until the issue if fixed.

It is his fault, not your. You cannot do anything about it.

[tboucheau]

Really ? There should be PVDm modules in my configuration ?

What a disaster...

Thanks for the answer...

[troullier00]

I can't say for sure if you need PVDMs or not unless I know exactly what hardware you are using. If the NM/VWIC has appropriate DSPs then you should be fine. Unless you can post your hardware and network setup then there is nothing we can do. You should really get your ISP to help you out on this.

[tboucheau]

So it's a NM-HD-2V with 2 VIC2-2BRI-NT/TE on each router. One with 3 BRI connected and one with 4 BRI connected.

I only want to be sure that should allow me to have 4 simultaneous calls before coming back to my ISP. Thanks for your advices.

[troullier00]

Yes that module has a single DSP which will support up to 4 calls when using a medium complexity Codec.

[tboucheau]

Ok i'll check the modem complexity and will go back to my ISP. Thanks for this answer.

Regards

[DelaporteOlivier]

Hello,

I'm working with Tony Boucheau (the poster) on this case.

After check, the NM-HD-2V can "Supports up to eight channels of analog/BRI voice using medium complexity codec or six channels using any supported codec."

Source :

http://www.cisco.com/warp/public/cc/pd/rt/ps282/prodlit/guido_ds.pdf

So normaly, no problem of DSP with 4 calls on this module... I suspect maybe a wrong dspfarm configuration,

because it's allways the 4th call and more, even if all calls are on a single router or if they are split into the two routers.

The symptom are always the same on the 4th call and the next ones (whatever which BRI ports is used) :

The incoming voice from the PSTN is perfect.

The outgoing voice from BRI ports has :

a very big latence (~ 3-4sec compared to 0.5sec on a normal call)

a metalic sound

a loss of some parts

ununderstanble voice

We'll post the configuration when we get it, and it will better if we get a "

show voice dsp" too.

Thanks

[paolo bevilacqua]

Unlikly it's a config issue.

Try reloading trhe router, even better a power cycle.