Station to Station SIP calls dropping at ~32 seconds

[SWITCHDOG]

Turning up multiple Spectralink 8742 phone on a Spectralink CMS.

WI-FI AP and controllers (Fortinet) are on the Spectralink approved list

Switch is an Avaya CM6, Critical reliability, CM 6.3, trunks are ISDN PRI

All switch fabric is in the same class C, access points are in a separate class C, no VLAN filtering

Problem: Calls to TDM trunks and endpoints will stay up forever. Calls between the Spectralink handsets are dropping at ~32 seconds. There are no other IP endpoints on the CM to test with.

List trace shows minor jitter, nothing major.

 

[kyle555]

30 seconds is a telltale sign that some message wasn't answered - like some 200OK or something.

Do the phones go straight to SM, or is it something like DECT where all the APs and controller are non-SIP and it translates to SIP somewhere so SM sees everything from 1 place?

 

[SWITCHDOG]

Spectralink 8742 is a SIP station on the Avaya CM, provisoning is done on session manager and the Spectralink CMS.

 

[kyle555]

I'll bet that the drop is because of some message is not being received from the Spectralink side towards SM. Do you have any other SIP stations working properly? Were you to register 2 One-X Communicator SIP softphones instead of the Spectralinks, do you have the same problem?

 

[SWITCHDOG]

The PIVOTS are the first foray into SIP stations on this particular CM. I'm waiting for the network team to wireshark it to see where the signalling is being blocked.

will try the softphones Monday

 

[kyle555]

try to validate Avaya SIP phones if you can - it'll at least confirm your config. There are a few quirks to setting up SIP stations. There are also firewalls that by default have a "sip application layer gateway" enabled by default and manipulate sip signaling to try to help.

You can avoid wireshark by getting a SIP Avaya phone working in a subnet very close to the SM and test again from where these phones are operating to confirm/deny. Otherwise, if there's a firewall in between and it's doing SIP manipulation, odds are you'll get the firewall support saying "yes I see packets and yes I'm letting them flow through. It must be your problem!