[SR-Users] Stupid NAT tricks to learn from Apple

Kristian Kielhofner kris at kriskinc.com
Fri Sep 20 16:01:43 CEST 2013

On Fri, Sep 20, 2013 at 9:36 AM, Olle E. Johansson <oej at edvina.net> wrote:
> 20 sep 2013 kl. 15:16 skrev Kristian Kielhofner <kris at 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
> http://www.rfc-editor.org/rfc/rfc7021.txt
> /O


  Great point!  I've updated my blog post with this information.


Kristian Kielhofner

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