[SR-Users] RTPProxy and bridging IPv4/IPv6 with parallel forking

[Klaus Darilion]

Am 14.04.2011 09:55, schrieb Olle E. Johansson:
> 
> 14 apr 2011 kl. 09.48 skrev Klaus Darilion:
> 
>> 
>> 
>> Am 13.04.2011 15:55, schrieb Daniel-Constantin Mierla:
>>> If does not work with one instance, I would use branch flags to
>>> mark the branch doing ipv4 to ipv6 translation and engage a
>>> dedicated rtpproxy for it. You can run two rtpproxy-es on the
>>> same server, in different sets: 
>>> http://kamailio.org/docs/modules/stable/modules_k/rtpproxy.html#id3012059
>>>
>>> 
http://kamailio.org/docs/modules/stable/modules_k/rtpproxy.html#id3009496
>>> 
>>> So the branch doing ipv4-ipv6 will have a flag set and use a
>>> particular rtpproxy. On the 200ok, you can check the branch flag
>>> and engage again the proper rtpproxy.
>> 
>> That's a nice idea. Some time ago I tried the same setup and
>> failed. Are there some easy methods to find out if a target is IPv4
>> or IPv6, e.g. something like
>> 
>> if ( is_ipv6("$rd") ) { ... }
>> 
> Now you have opened a can of worms. Let me start :-)
> 
> If I have a dual stack UA and registers with an IPv4 address - how do
> you know that I'm dual stack? I really don't need an RTP proxy.

Maybe the rtpproxy is used anyway (NAT traversal, legal intercept ...)

> The IETF thinks we should use SIP outbound and register twice.
> Kamailio doesn't support this as far as I remember and won't see that
> we have two locations for the very same UA.
> 
> Now, if you have a URI like "sip:board at kamailio.org" and that URI's
> domain has two priority levels of SRV records. The first level is
> only IPv4 and the second level includes IPv6 to indicate a preference
> to receive calls in IPv4 and an ability to receive them in IPv6 if
> that's preferred by the caller. Would Kamailio understand this?

No. Because in branch route you only see the domain, you will not know
if the request will be forwarded via IPv4 or IPv6.

But to be pragmatic: for a service provider without "open SIP
connectivity" it does not matter as the customers will use IP addresses
and not domains for there clients.

regards
Klaus

> There is work to be done here. /O
> 
> 
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