Hi there, Well it's mostly rtpengine question but didn't know where should I send it and probably the answer will be more or less useful for kamailio users.
By default if an offer has ICE candidates rtpengine leaves them untouched and just inserts itself as an additional low priority candidate and also rewrites c= line for the callee without ICE support. Using ICE=force-relay rtpengine inserts itself as a "relay" candidate what is great but doesn't touch c= line and callee without ICE have no chance to send RTP to rtpengine. Is it possible somehow to make a third behavior like force-relay + rtpengine IP in c= param? It would allow any callee to send media to rtpengine regardless of ICE support.
On Thu, Mar 14, 2019 at 02:47:24PM +0200, Vitalii Aleksandrov wrote:
Well it's mostly rtpengine question but didn't know where should I send it and probably the answer will be more or less useful for kamailio users.
I get the feeling. You could open an issue in github, but sipwise/rtpengine devs frequent here.
By default if an offer has ICE candidates rtpengine leaves them untouched and just inserts itself as an additional low priority candidate and also rewrites c= line for the callee without ICE support. Using ICE=force-relay rtpengine inserts itself as a "relay" candidate what is great but doesn't touch c= line and callee without ICE have no chance to send RTP to rtpengine. Is it possible somehow to make a third behavior like force-relay + rtpengine IP in c= param? It would allow any callee to send media to rtpengine regardless of ICE support.
What is wrong with the default behavior? That adds ICE records and rewrites SDP c=.
On 14.03.19 17:09, Daniel Tryba wrote:
On Thu, Mar 14, 2019 at 02:47:24PM +0200, Vitalii Aleksandrov wrote:
Well it's mostly rtpengine question but didn't know where should I send it and probably the answer will be more or less useful for kamailio users.
I get the feeling. You could open an issue in github, but sipwise/rtpengine devs frequent here.
It's not a bug. rtpengine works exactly as described in docs. Maybe a feature request issue.
By default if an offer has ICE candidates rtpengine leaves them untouched and just inserts itself as an additional low priority candidate and also rewrites c= line for the callee without ICE support. Using ICE=force-relay rtpengine inserts itself as a "relay" candidate what is great but doesn't touch c= line and callee without ICE have no chance to send RTP to rtpengine. Is it possible somehow to make a third behavior like force-relay + rtpengine IP in c= param? It would allow any callee to send media to rtpengine regardless of ICE support.
What is wrong with the default behavior? That adds ICE records and rewrites SDP c=.
When a call goes through multiple proxies and every proxy inserts itself SDP becomes really huge. What I like in "force-relay" is that it removes previously inserted "relay" candidates and inserts itself. Hope rtpengine will still talk to those relay candidates on incoming leg if "host" are not reachable. So I'm satisfied with "force-relay" when call to ICE supported phone, but when callee can't do ICE I'm in trouble.
On Thu, Mar 14, 2019 at 06:01:41PM +0200, Vitalii Aleksandrov wrote:
What is wrong with the default behavior? That adds ICE records and rewrites SDP c=.
When a call goes through multiple proxies and every proxy inserts itself SDP becomes really huge. What I like in "force-relay" is that it removes previously inserted "relay" candidates and inserts itself. Hope rtpengine will still talk to those relay candidates on incoming leg if "host" are not reachable. So I'm satisfied with "force-relay" when call to ICE supported phone, but when callee can't do ICE I'm in trouble.
ICE is end to end. rtpengine does nothing with other ICE candidates (AFAIK). So removing those other candidates defeats the purpose IMHO. You might as well remove any ICE and simply rewrite DSP
On Thu, Mar 14, 2019 at 06:01:41PM +0200, Vitalii Aleksandrov wrote:
What is wrong with the default behavior? That adds ICE records and rewrites SDP c=.
When a call goes through multiple proxies and every proxy inserts itself SDP becomes really huge. What I like in "force-relay" is that it removes previously inserted "relay" candidates and inserts itself. Hope rtpengine will still talk to those relay candidates on incoming leg if "host" are not reachable. So I'm satisfied with "force-relay" when call to ICE supported phone, but when callee can't do ICE I'm in trouble.
ICE is end to end. rtpengine does nothing with other ICE candidates (AFAIK). So removing those other candidates defeats the purpose IMHO. You might as well remove any ICE and simply rewrite DSP
Oh, it actually does. If you use ICE=force, rtpengine removes all ICE candidates and inserts its own and both call participant can't to talk to each other directly but still can use ICE to establish media streams to rtpengine. ICE=force-relay does another cool thing. Using it call participants try to talk directly and if they can't (both behind NAT) they can still use "relay" candidate inserted by rtpengine and exchange media via it. I just need a mixed behavior like default + force-relay and don't want to hack rtpengine sources and then maintain my patches when need to update it.
On Fri, Mar 15, 2019 at 12:37:16PM +0200, Vitalii Aleksandrov wrote:
Oh, it actually does. If you use ICE=force, rtpengine removes all ICE candidates and inserts its own and both call participant can't to talk to each other directly but still can use ICE to establish media streams to rtpengine. ICE=force-relay does another cool thing. Using it call participants try to talk directly and if they can't (both behind NAT) they can still use "relay" candidate inserted by rtpengine and exchange media via it. I just need a mixed behavior like default + force-relay and don't want to hack rtpengine sources and then maintain my patches when need to update it.
How is this any different than the default ICE setting (without rewriting rtp)? rtpengine will add itself to ICE candidates (with a lower priority than already present ICE). Allowing the rtpengine to be skipped entirely if there is a better (higher priority) ICE candidate.
endpoint A with ICE support <-> rtpengine with ICE <-> endpoint B with ICE
Here RTP can go directly from A to B. If any point doesn't support ICE, the rtpengine will be used (with ICE for the endpoint that does support ICE) if rtpengine rewrites RTP for legacy endpoints.
The problem of removing ICE is more apparent with more parties involved: a <-> r1 <-> r2 <-> b
if a,r1 and r2 have ICE support but b doens't, do you want a to communicate with r1 or r2? If you remove ICE with force-relay, it will talk to r1, if you "do nothing", it may talk to r2 as ICE candidate.
On 15/03/2019 06.37, Vitalii Aleksandrov wrote:
On Thu, Mar 14, 2019 at 06:01:41PM +0200, Vitalii Aleksandrov wrote:
What is wrong with the default behavior? That adds ICE records and rewrites SDP c=.
When a call goes through multiple proxies and every proxy inserts itself SDP becomes really huge. What I like in "force-relay" is that it removes previously inserted "relay" candidates and inserts itself. Hope rtpengine will still talk to those relay candidates on incoming leg if "host" are not reachable. So I'm satisfied with "force-relay" when call to ICE supported phone, but when callee can't do ICE I'm in trouble.
ICE is end to end. rtpengine does nothing with other ICE candidates (AFAIK). So removing those other candidates defeats the purpose IMHO. You might as well remove any ICE and simply rewrite DSP
Oh, it actually does. If you use ICE=force, rtpengine removes all ICE candidates and inserts its own and both call participant can't to talk to each other directly but still can use ICE to establish media streams to rtpengine. ICE=force-relay does another cool thing. Using it call participants try to talk directly and if they can't (both behind NAT) they can still use "relay" candidate inserted by rtpengine and exchange media via it. I just need a mixed behavior like default + force-relay and don't want to hack rtpengine sources and then maintain my patches when need to update it.
You can always submit a pull request as long as it doesn't break existing functionality, e.g. by making it a new optional feature.
Cheers
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Daniel Tryba -
Richard Fuchs -
Vitalii Aleksandrov