VOIP calls get disconnected if placed on hold

[Comm12]

Hi - new to IPO. Here's the problem we have:

While inter-office 4 digit calls from site to site via IPO networking channels otherwise work OK, if the calling party is placed on hold, they get disconnected after approximately 1 minute and 50 seconds. I know this is a long time for someone to be placed on hold but due to the nature of their business the customer frequently has to place callers on hold for several minutes at a time.

The call is disconnected after the approximate one minute and 50 second interval even when they are taken off hold after only a few seconds, or when the call timer triggers a ring back to the phone that has placed the call on hold. The current hold call back timer in System settings is for 90 seconds. If the calling party is taken off hold upon the hold call timer ringing back the phone, I believe the caller is dropped after about 20 seconds (1 minute 50 seconds - minus the 90 second call back timer). The call is disconnected without warning, sound, or any error displaying on the phone.

It seems the trigger is when the inter-office VOIP caller is placed on hold regardles of how long they are on hold for. If the caller is not placed on hold their is no disconnect. Callers to the customer's POTS lines do not get disconnected after being placed on hold.

The customer is running 6.018 at each site on IPO 500 V2s with a combo card in each providing 10 VCM channels. Phones are the digital model 1416.

The current VOIP networking channel configuration is via QSIG. QSIG is currently being used because though SCN when configured registers as "Up" in System Status and you can see the hunt groups from other sites callers get an "Unobtainable" message when they try to 4 digit dial another office. But I think this may be a separate issue to the hold disconnect issue - and seems to possibly be related to the data vendor needing to open the approporiate ports in the firewall.

I have not had a chance yet to look at the on hold call issue via System Status or Monitor. But if anyone has had any experience with the hold disconnect issue ( or the SCN issue) and has suggestions please let me know.

Thanks

 

[tlpeter]

Sounds like the connection between sites isn't very good.
When scn doesn't work and QSIG either then I think I am in the right direction.

When you pay peanuts, you get monkeys!

honey, i fried the IP Office !!!

Sarcasm, it's only one of the services I offer.

 

[Comm12]

Thanks for the reply. I would agree that there are probably network issues that need to be resolved. But just to be clear, when I configure the networking channels to use QSIG or H450 IP calls between offices work OK.

It is only when the IP caller is placed on hold that they consistently get disconnected after a certain amount of time has elapsed. This happens to every VOIP call that is placed on hold.

Does anyone have any suggestions on what might be causing the disconnect on hold that I could talk to the customer's data vendor about? Or could it be something in the IPO settings that I need to tweak?

Thanks.

 

[TheSmash]

Have you run a trace and captured this?

ACSS (SME)

I never touched anything...

 

[intrigrant]

Each H.323 line trunk needs to have a unique Incoming/Outgoing line ID number within the scn, this sounds like a anti-tromboning issue.
Call on Hold on remote site times out, local IP Office tries to recapture the call but it cannot because there are conflicting line IDs, the stupid box gets confused and drops the line.

 

[Comm12]

Thanks All. I plan to be there later today to do some more testing and will look into your suggestions about running a trace and reconfiguring the lines with unique I/O line IDs.

 

[kwing112000]

What type of Data devices are in between. I have seen things like this when the fix-ups/Inspect options on cisco are not disabled.

Kevin Wing
ACSS Small and Medium Enterprise (SME) Communications
ACS- Implement IP Office
ACA- Implement IP Office
Carousel Industries

 

[Comm12]

They have Sonic Wall TZ 190's at each site with HP Pro Curve switches. Sites are small - 8-12 users per site. Presently they use Comcast cable as their internet provider but will begin transitioning to an MPLS network soon. Any known issues with the Sonic wall relative to the hold issue or SCN?

Thanks

 

[Comm12]

Hi- just a follow up for future reference...

I was able to resolve the hold disconnect issue by rebuilding the lines using new unique line numbers and the H450 protocol instead of QSIG. It seems that the key difference was using H450 instead of QSIG as new line numbers using QSIG did not resolve the issue. I don't know if this was/is a by product of issues on the network, or if QSIG is just not as IPO compatible as H450.

Now if I can just get SCN to work I can re-build the lines using SCN instead of H450 and I'll really be all set

Thanks to all for your help.

 

[DanACS]

You should use Park for putting people on hold for long periods not hold.

ACS - IP Telephony + IP Office
ACA - Too many to remember
ACSS - Would do it but i don't get a free TShirt anymore!

 

[tlpeter]

The sonicwalls do have a H.323 inspect which should be turned off.
Read this topic:

http://www.tek-tips.com/faqs.cfm?fid=7323

When you pay peanuts, you get monkeys!

honey, i fried the IP Office !!!

Sarcasm, it's only one of the services I offer.

 

[Comm12]

The Sonic Wall fix Faq may be the root cause of the SCN issue I am having because when configured the SCN trunk shows as "Up" in System Status. But when you dial a remote extension, you get an "Unobtainable" message on the display even though you can dial the same extension when that same line is configured as H450 or QSIG. I will check it out and let you know.

Thanks again.

 

[TheSmash]

Oooooh, Sonicwall and SCN... not a good mix.

I have an outstanding issue with Avaya which they are trying to work out. SCN drops periodically and then re-establishes itself 15 seconds later. Get the dreaded "Unobtainable" message during this 15 seconds. This is on V5 but sounds similar, if not as severe as what you are experiencing. It was fine on V4.

And before anyone says it, yes, H323 Transformations have been disabled...

ACSS (SME)

I never touched anything...

 

[intrigrant]

It is documented that you MUST use H.450 for a SCN, this is the default value anyway. Never change default values unles documentation tells you to change it, good lesson here.

Anti tromboning only works within a SCN with H.450 AND unique line ID's but it is not often noticed if anti tromboning doesn't work.