Nortel SMC 2450, Implementation Manual

Page: 39 / 262

Description Page 39 of 260
Secure Multimedia Controller Implementation Guide
Media stateful filter
The SMC acts as a stateful filter for Real-time Transport Protocol (RTP)
media traffic. The SMC protects the Media Gateways from attacks, such as
User Datagram Protocol (UDP) floods. To protect the gateways, the SMC lets
a media stream come into the SMZ only if the gateway initiated a stream
going out first.
Secure UNIStim proxy
UNIStim is a Nortel-proprietary signaling protocol used within the MCS and
CS 1000 product lines; however, the first release of the SMC supports only
CS 1000. Using UNIStim, a UNIStim IP phone communicates with a
UNIStim server (TPS) using the User Datagram Protocol (UDP). The SMC
Secure UNIStim proxy provides the following functionality:
• Secure UNIStim support
• transparent proxy support
• granular policies
• key management
Secure UNIStim support
The transparent UNIStim security proxy within the SMC enables UNIStim IP
phones to communicate with insecure UNIStim servers in a protected
fashion, with encryption terminated at the SMC before the unencrypted
traffic is passed to the back-end server. Nortel recommends that you install
the SMC in close proximity to the server to minimize the exposure of insecure
traffic.