This is an example of how to modify a SIP header with an Acme Packet Session Border Controller (SBC). An SBC is a device most commonly used by Service Providers to provide topology hiding between their SIP platform and the public Internet. In the most simplistic terms think of it as a Cisco PIX or ASA but explicitly dedicated to Voice over IP (SIP, H.323, MGCP).
The topology in this scenario is an Avaya IP PBX with a SIP Trunk registered to an ITSP’s SIP platform running Broadsoft Broadworks. The Avaya user wants to place an anonymous outbound call but the Avaya platform is sending the SIP URI as restricted@sip.domain.com rather than anonymous@sip.domain.com. Although RFC 3261 does not forbid a User Agent Client (UAC) from using something other than anonymous, using anonymous is recommended. However, Avaya chose not to follow the recommendation.
Our Acme Packet SBC is physically located in the core of the network but provides the logical separation between all customer facing devices and the core Broadworks cluster nodes. This means all SIP signaling must traverse through the SBC before reaching Broadworks. This provides a huge benefit when it comes to SIP incompatibilities between various vendors. In this case we can modify the messaging coming from the Avaya IP PBX and literally replace anything that matches a URI with restricted@ and send anonymous@ before the SBC passes the messaging to Broadworks.
I have provided the examples in the form of screenshots to retain the formatting of the Acme Packet configuration text placement.
The first step in doing this is to create the actual SIP manipulation rules in the Acme Packet SBC.
The second step is to assign the SIP manipulation rule to the Access realm where the Avaya’s signaling is coming in.
The in-manipulationid parameter is what tells the SBC to identify a match for the values assigned to anonSwitch. If there is a match, the URI is modified and successfully sent to Broadworks.