I've been spending some time looking at some of the significant changes Apple has made to Facetime in iOS 7. I'm far from an Apple fanboy but some of them are pretty interesting:
- multiplexing everything over a single UDP port - deflate compression with SIP - various /slight/ protocol violations ;)
More here:
http://blog.krisk.org/2013/09/apples-new-facetime-sip-perspective.html
As SDP bodies swell more and more can we hope to build significant support for multiplexing and deflate compression in the SIP-focused open source ecosystem?
20 sep 2013 kl. 15:16 skrev Kristian Kielhofner kris@kriskinc.com:
I've been spending some time looking at some of the significant changes Apple has made to Facetime in iOS 7. I'm far from an Apple fanboy but some of them are pretty interesting:
- multiplexing everything over a single UDP port
That's what's Google has done with Hangouts and what we're currently working on in the IETF to standardize, driven by WebRTC. Will be very beneficial for all VoIP.
- deflate compression with SIP
- various /slight/ protocol violations ;)
getting depressed....
/O
More here:
http://blog.krisk.org/2013/09/apples-new-facetime-sip-perspective.html
As SDP bodies swell more and more can we hope to build significant support for multiplexing and deflate compression in the SIP-focused open source ecosystem?
-- Kristian Kielhofner
SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list sr-users@lists.sip-router.org http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users
--- * Olle E Johansson - oej@edvina.net * Cell phone +46 70 593 68 51, Office +46 8 96 40 20, Sweden
20 sep 2013 kl. 15:16 skrev Kristian Kielhofner kris@kriskinc.com:
I've been spending some time looking at some of the significant changes Apple has made to Facetime in iOS 7. I'm far from an Apple fanboy but some of them are pretty interesting:
- multiplexing everything over a single UDP port
After reading your very good blog entry (thanks!) I suspect that they have gone the extra way and mixed SIP/RTP/RTCP due to carrier grade nats. There's a new RFC describing issues with those and one is a shortage of ports. Every customer gets only a few allocations and only one per common port. ONly one SIP phone on 5060 as an example.
Limiting the number of ports used will not only make firewall traversal easier, it will make CGN traversal easier. While waiting for the real stuff - IPv6.
Blog: http://blog.krisk.org/2013/09/apples-new-facetime-sip-perspective.html CGN RFC: http://www.rfc-editor.org/rfc/rfc7021.txt
/O
On Fri, Sep 20, 2013 at 9:36 AM, Olle E. Johansson oej@edvina.net wrote:
20 sep 2013 kl. 15:16 skrev Kristian Kielhofner kris@kriskinc.com:
I've been spending some time looking at some of the significant changes Apple has made to Facetime in iOS 7. I'm far from an Apple fanboy but some of them are pretty interesting:
- multiplexing everything over a single UDP port
After reading your very good blog entry (thanks!) I suspect that they have gone the extra way and mixed SIP/RTP/RTCP due to carrier grade nats. There's a new RFC describing issues with those and one is a shortage of ports. Every customer gets only a few allocations and only one per common port. ONly one SIP phone on 5060 as an example.
Limiting the number of ports used will not only make firewall traversal easier, it will make CGN traversal easier. While waiting for the real stuff - IPv6.
Blog: http://blog.krisk.org/2013/09/apples-new-facetime-sip-perspective.html CGN RFC: http://www.rfc-editor.org/rfc/rfc7021.txt
/O
Olle,
Great point! I've updated my blog post with this information.
Thanks!
Hello,
interesting, thanks for sharing!
What else I could say, I am really deeply extremely ... (can't find other words) ... shocked they don't use SIGCOMP specs [ha ha!]! I remember some discussions when I said that usage of one well established compression algoritm will get it done in few hours (implementatio wise) than what IETF came up with in this regard. Sad but true, many IETF specs have no touch with reality...
Maybe I missed while quick reading, what are the "various /slight/ protocol violations" you spotted?
Cheers, Daniel
On 9/20/13 3:16 PM, Kristian Kielhofner wrote:
I've been spending some time looking at some of the significant changes Apple has made to Facetime in iOS 7. I'm far from an Apple fanboy but some of them are pretty interesting:
- multiplexing everything over a single UDP port
- deflate compression with SIP
- various /slight/ protocol violations ;)
More here:
http://blog.krisk.org/2013/09/apples-new-facetime-sip-perspective.html
As SDP bodies swell more and more can we hope to build significant support for multiplexing and deflate compression in the SIP-focused open source ecosystem?
Hi Daniel,
I know, shocking (heh)!
The protocol violations were very slight - omitting SDP rtpmap lines for dynamic RTP payloads, omitting a=rtcp-mux for RTP+RTCP mux (but they're already muxing SIP too, so ehh). Possibly others.
On Fri, Sep 20, 2013 at 10:19 AM, Daniel-Constantin Mierla miconda@gmail.com wrote:
Hello,
interesting, thanks for sharing!
What else I could say, I am really deeply extremely ... (can't find other words) ... shocked they don't use SIGCOMP specs [ha ha!]! I remember some discussions when I said that usage of one well established compression algoritm will get it done in few hours (implementatio wise) than what IETF came up with in this regard. Sad but true, many IETF specs have no touch with reality...
Maybe I missed while quick reading, what are the "various /slight/ protocol violations" you spotted?
Cheers, Daniel
On 9/20/13 3:16 PM, Kristian Kielhofner wrote:
I've been spending some time looking at some of the significant changes Apple has made to Facetime in iOS 7. I'm far from an Apple fanboy but some of them are pretty interesting:
- multiplexing everything over a single UDP port
- deflate compression with SIP
- various /slight/ protocol violations ;)
More here:
http://blog.krisk.org/2013/09/apples-new-facetime-sip-perspective.html
As SDP bodies swell more and more can we hope to build significant support for multiplexing and deflate compression in the SIP-focused open source ecosystem?
-- Daniel-Constantin Mierla - http://www.asipto.com http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda Kamailio Advanced Trainings - Berlin, Oct 21-24; Miami, Nov 11-13, 2013
- more details about Kamailio trainings at http://www.asipto.com -
SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list sr-users@lists.sip-router.org http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users
Hi Kristian,
On 9/20/13 5:15 PM, Kristian Kielhofner wrote:
Hi Daniel,
I know, shocking (heh)!
The protocol violations were very slight - omitting SDP rtpmap lines for dynamic RTP payloads, omitting a=rtcp-mux for RTP+RTCP mux (but they're already muxing SIP too, so ehh). Possibly others.
ahh, ok, I remarked your notes about, but somehow I had in mind only the SIP part (headers), not the SDP body. I was looking to see if they use some custom format or not-specified values for headers...
Thanks, Daniel
On Fri, Sep 20, 2013 at 10:19 AM, Daniel-Constantin Mierla miconda@gmail.com wrote:
Hello,
interesting, thanks for sharing!
What else I could say, I am really deeply extremely ... (can't find other words) ... shocked they don't use SIGCOMP specs [ha ha!]! I remember some discussions when I said that usage of one well established compression algoritm will get it done in few hours (implementatio wise) than what IETF came up with in this regard. Sad but true, many IETF specs have no touch with reality...
Maybe I missed while quick reading, what are the "various /slight/ protocol violations" you spotted?
Cheers, Daniel
On 9/20/13 3:16 PM, Kristian Kielhofner wrote:
I've been spending some time looking at some of the significant changes Apple has made to Facetime in iOS 7. I'm far from an Apple fanboy but some of them are pretty interesting:
- multiplexing everything over a single UDP port
- deflate compression with SIP
- various /slight/ protocol violations ;)
More here:
http://blog.krisk.org/2013/09/apples-new-facetime-sip-perspective.html
As SDP bodies swell more and more can we hope to build significant support for multiplexing and deflate compression in the SIP-focused open source ecosystem?
-- Daniel-Constantin Mierla - http://www.asipto.com http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda Kamailio Advanced Trainings - Berlin, Oct 21-24; Miami, Nov 11-13, 2013
- more details about Kamailio trainings at http://www.asipto.com -
SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list sr-users@lists.sip-router.org http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users
-
Daniel-Constantin Mierla -
Kristian Kielhofner -
Olle E. Johansson