[Serusers] Theory behind a media proxy and NATed UA

[Felipe Louback]

The problem with NAT is because the IP address of the SDP body is a
non routeable IP. So how does a media proxy works?

I read that a media proxy put his address at the sdp body and both UA
talks with the media proxy instead of each other. At the time a NAT
user sends an INVITE, there is no corresponding port on the NAT. So
How does a media proxy contact the NATed UA?
 Isn't this the same problem the called part will have to contact the
NATed party?

I read a couple of papers about it, but in all of them it is said that
both ends talk to the media proxy and that is all. No explanation
about how things work. I know it works because I am using mediaproxy.

If anyone could point me how this works or where I can find a document
explaining....

Thanks,

Felipe

--
Master Student - Electrical Engineering Department
Computer Engineering and Telecommunications Research Group
Universidade Federal de Minas Gerais - Brazil

"For God so loved the world that he gave his one and only Son, that
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John 3:16