AudioCodes Mediant 800 User Manual page 784

CHAPTER 30 SBC Overview
The first stage of the SIP dialog-initiating process is determining source and destination URLs.
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.
■ All SIP requests (e.g., INVITE) except REGISTER:
● Source URL: Obtained from the From header. If the From header contains the value
'Anonymous', the source URL is obtained from the P-Preferred-Identity header. If the P-
Preferred-Identity header does not exist, the source URL is obtained from the P-Asserted-
Identity header.
● Destination URL: Obtained from the Request-URI.
■ REGISTER dialogs:
● Source URL: Obtained from the To header.
● Destination URL: Obtained from the Request-URI.
Mediant 800 Gateway & E-SBC | User's Manual
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