Administrator's Guide

Chapter 11. SIP Traffic
SIP (Session Initiation Protocol) is a protocol for creating and terminating various media
stream sessions over an IP network. It is for example used for Internet telephone calls and
distribution of video streams.
SIP takes care of the initiation, modification and termination of a session with one or more
participants. The protocol makes it possible for the participants to agree on what media types
they should share. You can find more information about SIP in appendix A, More About SIP,
and in RFC 3261.
The SIP module in the 3Com VCX IP Telecommuting Module handles SIP requests for
users who have registered on the Telecommuting Module itself or a machine connected to the
Telecommuting Module (see also Local Registrar). The Telecommuting Module receives the
request via the firewall (or, for the Standalone type, directly from the clients) and processes
it. When the SIP negotiation is finished, the Telecommuting Module lets the media streams
of this SIP session through. All media streams pass through the Telecommuting Module if
the clients are located on different firewall interfaces.
These SIP functions are configured in the SIP Traffic section:
• Allowed SIP methods
• Filtering of SIP signaling
• Local SIP domains
• SIP users
• SIP user authentication
• RADIUS accounting for SIP
• Routing of outgoing SIP requests
• Routing of incoming SIP requests
SIP Methods
Enter the SIP methods you want to allow and/or authenticate. Methods that are not listed
here will be blocked by the Telecommuting Module.
Common methods are predefined (from RFC 3261). Note that the standard methods ACK
and CANCEL cannot be authenticated.
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