Re: [Sip-implementors] Handoff

2016-07-07 Thread Roman Shpount
On Thu, Jul 7, 2016 at 2:28 PM, Volkan Hatem wrote: > In fact, these were the cases where I doubted the reasoning behind "no > retransmission over TCP/TLS" for INVITE etc when you absolutely need it. > We actually always use UDP like re-transmits even when sending SIP messages over TCP or TLS. T

Re: [Sip-implementors] Handoff

2016-07-07 Thread Roman Shpount
On Thu, Jul 7, 2016 at 11:49 AM, Dale R. Worley wrote: > My impression is that this problem is most commonly seen switching > between a mobile connection and a WiFi connection, but it can happen in > pure-SIP situations as well. > > So far, it seems that a UA could use INVITE-with-Replaces (sent

Re: [Sip-implementors] Handoff

2016-07-07 Thread Volkan Hatem
Hi Paul, You are absolutely right but make-before-break is only possible, as you said, if you can get some advance warning. I think the most suitable case is cellular-to-WiFi. In this case both networks will be available, we can make, verify and only after that handoff. However, WiFi-to-Mobile mi

Re: [Sip-implementors] Handoff

2016-07-07 Thread Volkan Hatem
BTW, Everything I wrote assumes UA perspective. IMS like tighter integrations have the luxury of the advance warning and support of the network. -volkan 2016-07-07 21:28 GMT+03:00 Volkan Hatem : > Hi Paul, > > You are absolutely right but make-before-break is only possible, as you > said, if yo

Re: [Sip-implementors] Handoff

2016-07-07 Thread Brett Tate
> So far, it seems that a UA could use INVITE-with-Replaces > (sent from the new interface to the other party) to > transfer the dialog from its old interface to its new > interface. Has anyone implemented such a technique? Yes; with B2BUA acting upon Replaces. If it matters, solutions using thi

Re: [Sip-implementors] Handoff

2016-07-07 Thread Paul Kyzivat
ISTM that there is dubious likelihood of success of this is attempted after the previous connection has already failed. Make-before-break is safer if you can get some advanced warning. But make-before-break has its own implications on how you do this so that it doesn't become break-while-trying

Re: [Sip-implementors] Handoff

2016-07-07 Thread Volkan Hatem
Hi Dale, Indeed, INVITE-with-Replaces was the first alternative I could think of as well. However, in the case where I implemented the hand-off we could deterministically bring the SIP-UA to register with its "home" proxy which holds the current call-leg (dialog). A simple re-INVITE to update the

[Sip-implementors] Handoff

2016-07-07 Thread Dale R. Worley
Is there any generalized technique for "handoff", for moving a SIP dialog from one interface/medium to another? My impression is that this problem is most commonly seen switching between a mobile connection and a WiFi connection, but it can happen in pure-SIP situations as well. So far, it seems