Nortel Networks COMMUNICATION SERVER 1000 NN43021-110 - Manual (Page 54)

54 System architecture
The H.323 Gatekeeper and the SIP Redirect Server can reside on the
same Signaling Server. Examples of H.323 and SIP-compatible endpoints
needing the services of the NRS are CS 1000E. The NRS also supports
endpoints that do not support H.323 Registration, Admission, and Status
(RAS) or SIP registration with the NRS.
Note: Systems that do not support H.323 RAS procedures and H.323
Gatekeeper procedures are referred to as non-RAS or static endpoints.
Each CS 1000E in an IP Peer network must register to the NRS. The NRS
software identifies the IP addresses of PBXs based on the network-wide
numbering plan. NRS registration eliminates the need for manual
configuration of IP addresses and numbering plan information at every
site.
SIP Proxy
Communication Server (CS) 1000 Release 5.5 adds a transaction stateful
SIP Proxy to the IP Peer Network.
A SIP Proxy acts as both a server and a client. A SIP Proxy receives
requests, determines where to send the requests, and acting as a client on
behalf of SIP endpoints, passes requests to another server.
A SIP Proxy makes the following features and functionality, which are
provided by CS 1000 Release 5.5, possible:
1. Transport Layer Security (TLS).
TLS provides the NRS with private, secure signaling, message
authentication, confidentiality, and integrity through end-to-end
encryption of media exchanged between two SIP endpoints.
2. Mixed transport layer protocol.
A mixed transport layer protocol enables gateways using TCP, TLS
over TCP, or UDP to interoperate.
3. Network features.
By default the SIP Proxy and Redirect Server functions as a SIP Proxy.
However, an endpoint can request transaction by transaction that the
SIP Proxy act as a SIP Redirect Server.
A SIP Redirect Server receives requests, but does not pass the
requests to another server. Instead, a SIP Redirect Server sends a
response back to the SIP endpoint, indicating the IP address of the
called user.
4. Post-routing SIP URI modification.
5. Transaction forking.
Nortel Communication Server 1000
Communication Server 1000M and Meridian 1 Large System Overview
NN43021-110 02.05 Standard
30 September 2008
Copyright © 2003-2008 Nortel Networks
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