Version 7.2 609 Mediant 1000B Gateway & E-SBC
User's Manual 28. SBC Overview
28.3 Call Processing of SIP Dialog Requests
The device processes incoming SIP dialog requests (SIP methods) such as INVITE,
SUBSCRIBE, OPTIONS, REFER, INFO, UNSOLICITED NOTIFY, MESSAGE, and
REGISTER. The process is summarized in the following figure and subsequently
described:
Figure 28-2: SBC Call Processing
The SIP dialog-initiating process consists of the following stages:
1. Determining Source and Destination URL: The SIP protocol has more than one
URL in a dialog-initiating request that may represent the source and destination URLs.
The device obtains the source and destination URLs from certain SIP headers. Once
the URLs are determined, the user and host parts of the URLs can be used as
matching rule characteristics for classification, message manipulation, and call routing.