VoIP Mailing List Archives

[jbr at consiglia.dk]

How do I read the contents of the SIP headers sdp in a dialplan?

[brian at freeswitch.org]

Do you want the SDP or the SIP Headers? Your question is ambiguous!

SDP should be in ${switch_r_sdp}

X-Header should be in ${sip_h_X-Header}

The "info" app helps show all the variables.

/b


On Sep 17, 2008, at 2:11 AM, Jon Bruel wrote:

[jbr at consiglia.dk]

Well, let me be more precise: In general, I want to be able to modify the SIP headers to my liking. I would like to add a tag to the To-header sent to the B-phone. This tag information can be used at a later stage to put the phone on/off hold from the switch by sending a NOTIFY with an header: Event: hold or Event:talk.

[mike at jerris.com]

if you mean tag= param on the to header, there should be one added automatically as defined in rfc3261. To send the notify might be a bit trickier, I think we added a way to use an event to send a notify, are you trying to control as iff the user hit the hold button on their phone? In response to what?

Mike



On Sep 17, 2008, at 7:09 AM, Jon Bruel wrote:

[jbr at consiglia.dk]

Mike, in my test setup, no tags are added to the To-header by the FreeSWITCH. The reason why I want to control it? Well, many phones uses the tag to relate an existing call to a NOTIFY message (send after the INVITE has been sent) with the same headers (and the same to-tag) as the INVITE. I’m not aware of how this functionality is described in the RFC, though.
My aim is the check if I can use the FreeSWITCH to replicate a function known in BroadWorks. In this system, there are a number of plug-ins and web-interfaces which are used to control the SIP phone: Answer, put on hold and resume. The plug-in controls the application server through a XML interface, which in turn sends the NOTIFY to the phone. Thus the phone can be controlled without connectivity between the PC and the phone. These three states are controlled by a Notify message sent from the application server. So it would be useful to find a way of sending a Notify message to the phone from the FreeSWITCH. Other NOTIFY messages could be used for other useful things such as resetting the phone.

[mike at jerris.com]

Can you open up a bug on http://jira.freeswitch.org with full traces both of freeswitch and how broadworks does it, along with if possible the language about to tags from the rfc. There are a bunch of interop qwirks related to those tags and when they should or shouldn't be in there so we need to do that down in the sip stack, and need to understand more fully how this behaves in regards to other devices and the rfc.

Mike

On Sep 17, 2008, at 12:20 PM, Jon Bruel wrote:

[rob.dyck at telus.net]

There should be no To tag with the initial INVITE. The tag is added by the
callee per RFC3261.

On Wednesday 17 September 2008, Jon Bruel wrote:

[anthony.minessale at g...]

don't forget the bounty amount willing to pay for us to implement something to make it work.


On Wed, Sep 17, 2008 at 12:39 PM, Michael Jerris <mike@jerris.com (mike@jerris.com)> wrote:

[jbr at consiglia.dk]

Thank you for your replies. In checking the SIP messaging sequence, I saw that you are right about the source of the tag to the To-header: it is the phone, which as a response to the INVITE, adds the tag (and not, as I wrote, the FreeSWITCH). Still, we need a way to read it, and not the least to send NOTIFYs with the right tag. I have raised two issues on the Jira, maybe the category is wrong.
One of the tricky things to sort out is how to handle it in the case of bridging to a list of devices, and bridging to a user with multiple registrations. The NOTIFY method should include measures to send a NOTIFY to a specific phone among the many phones responding.
Thanks again for your excellent responsiveness – it adds the trust of the FreeSWITCH. Jon.

[mike at jerris.com]

On Sep 18, 2008, at 4:53 AM, Jon Bruel wrote: