Handle Session Timers

[egreenmachine]

FreeSwitch by default has Session Timeouts in the SIP headers. This header is documented in RFC4028

Session-Expires: 120;refresher=uas

The re-invites from FreeSwitch have identical SDP to what it sent on the original 200 OK (answer to the INVITE). We should be able to handle it by just sending a 200 OK with the SDP from the original INVITE. No ports or IP addresses have changed.

One potential issue I could see with this is if FreeSwitch decides to update the SDP to use a different IP address or Port. SIP.js has no way of updating the Peer Connection

[josephfrazier]

Note: this was reported in the Google Group: https://groups.google.com/forum/#!msg/sip_js/hzoMQ-xXIko/ZhTbocagi-oJ

[josephfrazier]

Putting this on the back burner for now. Partial work has been pushed to my sessiontimers branch, if anyone is interested in picking it up.

[markandrus]

@joseph-onsip there are a few commits on your branch that it looks like it would be nice to have in master, namely

• SIPMessage: dedupe Supported header generation into getSupportedHeader
• Grammar: parse Session-Expires/Min-SE header into object
• Grammar: parse Supported/Require header into list of values (I think this one would be useful even before session timer support)

any chance of getting those merged in, even before full session timer support is ready?

[josephfrazier]

Hey @markandrus, sorry for the latency on this. I've created https://github.com/onsip/SIP.js/pull/203 on your behalf, so the changes can be considered there.

[james-criscuolo]

Some work was done here, and is pushed on this branch:

https://github.com/onsip/SIP.js/tree/session-timers

The branch is a work in progress, but we hope it at least hits all the features we are looking to incorporate here.

[digitaldan]

Any updates or workarounds for this?