Cisco Call Manager & SIP Proxy

leblanc
leblanc used Ask the Experts™
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I was reading about SIP and in the phones setup process, they have to go through the SIP proxy server. Now if I look at the Cisco Call Manager, does the SIP proxy server part of the Cisco CM? Thanks
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Commented:
SIP is a protocol. Lync sends call over a SIP connection to CISCO, next CISCO routes the call to its destination

SIP is a protocol that runs on top on TCP/IP
http://en.wikipedia.org/wiki/Session_Initiation_Protocol
Callmanager is not a SIP Proxy. Proxy  is a different functionality within the SIP standard. Callmanager is a Back to back User Agent:

http://tools.ietf.org/html/draft-ietf-straw-b2bua-taxonomy-03

You could say Callmanager is a Proxy in the sense that, phones do not established connections to the final destination by themselves. They do not have a dial plan of their own (although you could provision a dialplan file on each phone, this is not really a dialplan per se as you don't get to choose different destinations for each call), so they are kind of dummy in these regards, they need Callmanager to proxy their request and process it somehow until it gets connected.

Callmanager can do many things with SIP calls, including handling of powerful features such as Single Number Reach, that is why a Back to back User Agent goes "beyond the the definition of a SIP Proxy"

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