Excessive re-invites

[thohiopatriot]

Friday our SIP provider told us that they are receiving excessive re-invites from our Mitel system. This causes their SIP server to temporarily blacklist our IP address and all calls go silent (loss of audio) for 5 minutes.

This is a new install and this problem has been happening since day 1 and we were very shocked just to be hearing about this now. However, the carrier says this is being caused by the Mitel System.

The system is 8.0 SP1 using MBG 10.0.3.14. The general call flow is as follows - SIP calls come in and traverse across a WAN to a Call Director Mailbox for a schedule and plays a greeting with 2 options. Once you make a choice the calls transfer to an ACD group back on the Local LAN (local to SIP trunks) that contains three different RAD Greetings (embedded VM). Calls hold until answered. Nothing out of the normal. Calls on hold range from 10-50 minutes as a rule. When this problem was identified recently there were 10 calls on hold with an average hold time of 6 minutes.

Question - Has anyone ever had a problem with excessive re-invites? Every have a carrier blacklist an IP because of re-invites?

 

[TCSI17]

You can try and enable 'Suppress Redirection Headers' in your SIP Peer Profile-->Signal and Header Manipulation tab, for that SIP Trunk provider then re-test.
Without seeing SIP traces its hard to know what exactly is happening. What it probably is, is the SIP provider is seeing SIP re-invites from any transfer or redirection that is happening on your Mitel system and they don't like it. Typically the SIP provider doesnt care what is happening on your system, therefore it should be setup so those messages don't get sent backwards.
Also, the amount of re-invites most likely is a factor of call volume in your ACD and each time a call plays a RAD greeting, they are being transferred to it, which causes the re-invite. Just my 2 cents.

 

[thohiopatriot]

TCS117 Thank you for your quick response.

We tried this setting (Suppress Redirection Headers) and it did not reduce the number of re-invites. After a packet capture and some evaluation, we determined that each call produces two re-invites each time a RAD message plays and returns to MOH. This particular customer had 3 RAD greetings in a couple of ACD Paths playing very frequently and the last greeting replaying. We changed the timers on the RAD's and was able to reduce the re-invites to a level that the carrier feels will be acceptable. Again, thank you for your reply and I will update after further evaluation.