[VoiceOps] The peer of my peer is my peer?
abalashov at evaristesys.com
Tue Jul 13 18:42:12 EDT 2010
On 07/13/2010 05:35 PM, Kristian Kielhofner wrote:
> I've seen this happen with resellers that only use a proxy between
> their customers (Bandwidth.com). In that case all transport, codec,
> and caller ID parameters must be compatible (Bandwidth won't do
> anything about them).
It's even worse if the end-users behind the ITSP's proxy are behind NAT.
You can do signaling-level NAT fixups in a proxy, but without relaying
media, you rely on the upstream carrier's edge equipment to do
draft-comedia style NAT traversal on the media, whereupon the true UDP
source port of the RTP is discovered prior to sending RTP to the
end-user leg (on the assumption of symmetric RTP), instead of using the
UDP port declared in the SDP body coming from the end-user.
Bandwidth.com's edge equipment does not do such fixups, so it is
entirely incumbent upon the ITSP to deal with this situation.
> With Level(3) Vector they hold media and can make codecs compatible.
> However, one problem we have found is Caller ID presentation. When
> going to a peer Level(3) will not do a dip and set the from name, they
> depend on the originating network to set the CID appropriately or they
> depend on the terminating network to do a dip.
... in E.164, no less.
Alex Balashov - Principal
Evariste Systems LLC
1170 Peachtree Street
12th Floor, Suite 1200
Atlanta, GA 30309
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