20 Sep
2013
20 Sep
'13
3:36 p.m.
20 sep 2013 kl. 15:16 skrev Kristian Kielhofner <kris(a)kriskinc.com>om>:
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