Voice Quality Issues Over SCN 2

[fakename05]

I have a customer that has 4 locations that are all SCN linked over their WAN. There are 2-406v2 systems, 1-412 at the central location, and 1-500. All of the sites use digital sets except the location with the IP500--they use 5610 sets. They have Cisco routers and switches. Everything sounds great most of the time but occasionally the voice quality is degraded so much that they hang up and use cell phones when calling between sites. Their voicemail also sounds bad from time to time.

The method of prioritization that they are using is to give the traffic from the IP address of the phone systems and from the voicemail pc the highest priority. That is how their network guys have it set up and they are blaming the poor audio quality on the fact that the 412 uses half-duplex on the ethernet port.

A tier 3 engineer isn't being much help. He simply says that it looks like network problems but offers no suggestions to what I should have their network people change to make this better.

Any suggestions?? This customer is getting frustrated. (and so am I!) Thanks for any help anyone can offer.

 

[MrIPO]

Guys if this by chance does not resolve, please send me all configurations reflecting 4.1(1201) and Router Configs via the emil link on the website below, I am happy to have a look for you and give further solutions.

Mr IPO

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[fakename05]

MrIPO,
I just got back from upgrading the customer from 4.12 to 4.1201 and the number of collisions on the port has gone from 2-3 a second to around 1 every minute or two.

The real test comes tomorrow when all of the users start making calls and loading the network but as of this moment things are really looking up.

Thanks for the extremely valuable post!

 

[MrIPO]

I thought this would be the case. !
I would still suggest you send the configs, and confirm the QoS on the Edge Routers for correct queue and diffserv markings.

Mr IPO

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[MrIPO]

Can you also confirm is the 412 LAN 1 interface connected to a ethernet interface on the router - or via Cisco Switch with the 100/half ?

Mr IPO

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[fakename05]

LAN 1 is connected to a Cisco switch that is set to 100/half.

I haven't called the customer this morning to see how many collisions they've had or if the voice is sounding better.

The other day there were collsions occurring constantly even late at night when there wasn't any traffic on the switch. Last night there were still a few but the number seemed to go down significantly.

I appreciate your offer to look at the configs. You are correct that Avaya wants all sorts of packet traces and so on before they'll move forward. I'm going to send over the system and router configs just as soon as they arrive from the customer. (I'm not on site at the moment)

Thanks again for all of your help.

 

[fakename05]

I think it's a little better than it was but the customer is still having problems with voice quality. Conversations sound pretty bad at times even after the upgrade.

Any other suggestions?

 

[tlpeter]

When there is a call check System status and go to active calls

Double click on a call to the other end and see if there is any latency and packet loss

It must be a call over the SCN


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[fakename05]

Several hours ago I put a Small Office Edition onto their LAN and made it part of the SCN. I connected a digital set to it and made a test call to a digital extension on the 412. I did this to sort of emulate a call that would be traveling across their WAN to see if I could take the WAN circuit out of the equation.

During the call I listened for warbling, echo, and other sound quality issues that you can hear over the calls that have been traveling across their WAN. We also watched the switch port to see if we had any collisions and/or output errors. I heard all the same problems that the distant SCN callers have been reporting. I especially heard the problems right as the call was being switched over to voicemail and that is when collisions and output errors showed up on the port.

Could a bad VCM module on the 412 cause these kinds of problems? It's a VCM 30 and it doesn't have any kind of echo cancellation on it.

It seems to me that this would at least help narrow down the problem back down to the 412.