[SIPForum-discussion] SIP and IPv4 mapped IPv6 addresses

[Kevin P. Fleming]

On 05/04/2010 10:43 PM, Prashantm at digilink.in wrote:

> In the mentioned scenario, when the IPv6 phone sends a 200 OK response,
> it will add its SDP as IPv6 address. How can the B2BUA map this IPv6
> address to an IPv4 address, so that the remote IPv4 guy can understand
> the SDP?

This is impossible; there is no generalized way to map an IPv6 address
into an IPv4 address, since there are 2^96 more addresses. It might be
possible to map a small subset if the B2BUA is made aware of a
correlation between two private network address spaces, but even that is
not trivial. In this scenario, the B2BUA would probably also have to act
as a media proxy and send its own addresses to the endpoints, so that it
can route the media between the networks that cannot reach each other.

-- 
Kevin P. Fleming
Digium, Inc. | Director of Software Technologies
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
skype: kpfleming | jabber: kfleming at digium.com
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