VVX 400 Not respecting "CANCEL" in "INVITE" on SLA


VVX 400 Not respecting "CANCEL" in "INVITE" on SLA



this is my first post...I've searched everywhere and cannot find anything that could cause this. We're a reseller and work on Polycom phones pretty regularly. 


Configuration Overview:

-I'm using FreeSwitch 1.6 as my SIP softswitch.  (Posting with FS as well)

-FreeSwitch is behind a firewall and NAT and my phones are behind firewalls and NAT.  (This is working for multiple customers without issues)

-I'm using SIP/TCP with NAT keep alives enabled every 20sec's

-SIP Compact Headers are enabled (to keep MTU below 1500 while traversing the firewall)


I do not think that I'm having any NAT issues, but I suppose that I could be.



Here is the issue:

I have two phones with multiple SLA's each (Line 1-5) and a Ring Group that rings the SLA's in order. (Freeswitch does SLA in Broadsoft mode)


The first phone will time out correctly after a certain number of rings and stop ringing but the second one continues to ring through another 20 secs. (The timeout value of the line). 


With a packet capture I found the initial INVITE to the DID which is then sent to the Ring Group app. The ring group then notify's both phones on the shared extension of the call setup. When the ringing timeout occurs due to no answer on the group I see the CANCEL notification sent in the NOTIFY headers to both phones. I see a 487 ack response from both as well. One phone stops ringing but the other continues. Is this a known issue? What could I be missing?


Any help is greatly appreicated. 


Have a great day!

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Polycom Employee & Community Manager

Re: VVX 400 Not respecting "CANCEL" in "INVITE" on SLA

Hello bissinc,

welcome to the Polycom Community.

It is always useful to include the currently used UC Software version as issues experienced or a question asked may already be addressed in a newer release.

This also allows yourself and others to check against current software release notes, Administrator Guides or FAQ post’s.

The above is also stated in the "Must Read First" and is the absolute minimum requirement every new post should include. .

In addition providing us with this basic information gives Polycom an idea what Software Versions are used in the field and avoids wasting time trying to troubleshoot issues which have already been addressed.

Therefore the Polycom VoIP FAQ contains this post here:

Question: How can I find out my SIP or UC Software Version of my Phone?
Resolution: Please check here


You may also want to look at this FAQ post:


Jan 19, 2012 Question: How to troubleshoot Polycom VoIP related Issues?

Resolution: Please check => here <=

Most likely you will need to open a ticket with support.

In order to raise a support ticket you need to work with your Polycom reseller as they need to do this for you.

If this is some sort of an Internet discounter please post either your phone's MAC address or your Polycom devices serial so I can look up who would be able to support you. This may not be who you purchased the Polycom device from.

Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.

Best Regards

Steffen Baier

Polycom Global Services


If official support is required please check how to phone or open a case here

The title Poly Employee & Community Manager is a community setting and does not reflect my role. I am just a simple volunteer in the community like everybody else. All posts and words are my own & do not represent the views of Employer.


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Notice: This community forum is not an official Poly support resource, thus responses from Poly employees, partners, and customers alike are best-effort in attempts to share learned knowledge.
Please also ensure you always check the VoIP , Video Endpoint , Microsoft Voice , PSTN or other FAQ's in the different sections
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