Call Quality Degrades Under Heavy Load

[IPOLackey]

Hi Guys,

We have a customer with an IP500v2 on 8.0.53. They used to have 60 channels of ISDN going into a Ubigate for a SIP gateway (There's a Historic Call Recorder they didn't want to lose). We recently added a further 15 SIP Trunks. Also they only use 1608 handsets for the tel-ops. It seems that when they go over 70 concurrent calls, the IPO seems to be failing and dropping packets. We checked this using Wireshar and it's extremely strange. The internal network is more than capable, and is the Fibre link for their SIP trunks.

So far we have replaced the 500, the VCM's and upgraded to 8.0 as they were on 6.0 to begin with. We have bypassed the router so we are now Point-Point with no natting or BGP. (It connects to our own ISP infrastructure so only 3 hops to the SIP trunk provider.) Also they are on G711 all the way through.

Is anyone aware of any issues with more than 70 SIP Trunks and full IP handsets? Has anyone found a solution yet?

Thanks,

 

[tlpeter]

The only thing i can think of is that you are using G.729 and not G.711.
G.729 requires compressing which is an extra step and uses more VCM channels (if used)

BAZINGA!

I'm not insane, my mother had me tested!

 

[IPOLackey]

It's definitely 711. Thought it might have been myself so checked on Wireshark. I can pull the calls and listen to them using Wireshark so it's 711.

 

[tlpeter]

Then it is G.711

Do you have 70 concurrent call all day long?
If that is the case then i get the feeling this is too much for the IPO.
Perhaps the server edition is better as it can handle more calls.


BAZINGA!

I'm not insane, my mother had me tested!

 

[crashtest1000]

I am trying to understand how you how you have ot configure.

If you SIP lines are directly connected to say the Lan 2 then once the call is set up it should go direct media so voip packets are not going through the system and the vcm is not used.

How is the recorder connected and do all the callgo via the ISDN to sip gateway.

 

[amriddle01]

crashtest, with SIP it still terminates onto the system physically so the you best you get RTP relay not true DMP, in this case the systems (fairly rubbish) LAN and/or LAN2 port(s) are still carrying the traffic


Avaya Implementation Qualified Professional Specialist Technical Engineer (AIQPSTE)

 

[IPOLackey]

The old setup was IP Handsets, to PRI cards, to an In-Line call recorder, then Ubigate for SIP Gateway.

I have just tested with just 75 channels of SIP on the IPO WAN and got a mass of warnings out on the Monitor Trace. Almost 100% the IPO just can't handle the traffic. These guys do 70+ concurrent calls all day long so come 11am the quality dies. Raised to Avaya and recommend to their Account Manager to upgrade.

Thanks for your thoughts.

 

[tlpeter]

70 concurrent calls at the same time all day long is too much.
This sounds like a big callcenter to me.


BAZINGA!

I'm not insane, my mother had me tested!

 

[amriddle01]

Yep, and Avaya claim it will take 128 SIP channels, I'd like to see that


Avaya Implementation Qualified Professional Specialist Technical Engineer (AIQPSTE)

 

[hairlessupportmonkey]

We do some of the busiest taxi firms in the UK, and some of these have 2 x ISDN 30s that fill up on good / bad days depending on how you look at it weather wise. Bad weather = lots of calls and have never has a single complaint about call quality.

ACSS - SME
General Geek

 

[IPOclueless]

Hi IPOLackey,

This really needs to be looked at by Avaya. If your saying that the calls start to degrade at 11 o'clock but are fine before 11 then this would indicate a potential memory issue.

I would recommend that a service request be opened up ASAP.


Ross Shorrocks | Avaya SME BackBone Engineer | Global Support Services

 

[IPOLackey]

Absolutely. Raised and waiting for a response. Just like to check with the guys who know.

 

[IPOclueless]

Do you know the SR#?

If you do, let me know it and I will look at it for you.

Ross Shorrocks | Avaya SME BackBone Engineer | Global Support Services

 

[amriddle01]

Sean, PRI's would be dependant on the LAN Port though and would at least half the load even if they were using IP phones


Avaya Implementation Qualified Professional Specialist Technical Engineer (AIQPSTE)

 

[IPOLackey]

Hi IPOClueless,

The SR# is 1-4102312432.

They had a fairly peacefull Friday and Monday but the issue has inflammed again this morning. I've sent on this morning's traces and see what we get.

Thanks.