AudioCodes Mediant 4000 SBC - Page 629

CHAPTER28 Advanced SBC Features
Mediant 4000 SBC | User's Manual
3. The device performs SIP message manipulation (Pre-classification Manipulation) on the
REGISTER messages to add a special parameter ("ac-int=<value>") to the Contact header to
identify the SIP Interface on which each message is received. For example:
● REGISTER for Primary Proxy received on SIP Interface "Interface-1":
REGISTER
To: <sip:100@audc.com>
Contact: <sip:100@172.17.100.20;ac-int=1>
● REGISTER for Secondary Proxy received on SIP Interface "Interface-2":
REGISTER
To: <sip:100@audc.com>
Contact: <sip:100@172.17.100.20;ac-int=2>
4. The device adds to the Contact header a special string with a unique value, "ac-feu=<value>"
for each registration (e.g., "Contact: <sip:100@172.17.100.20;ac-int=1;ac-feu=x>").
5. The device saves the two contacts (100@172.17.100.20;ac-int=1;ac-feu=x and
100@172.17.100.20;ac-int=2;ac-feu=y) under the same AOR (100@audc.com) in its user
registration database.
The SIP call flow for dual registration is shown below:
The basic SIP call flow for INVITEs to and from the registered user is shown below:
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