INVITEs UPDATEs Received by Second SBC

The second Oracle® Enterprise Session Border Controller receives the INVITE or UPDATE with the newly inserted Require: header. Standard SIP convention indicates that if the UAS receiving the request does not know how to handle the Require header, the request should be rejected.

When the following three conditions are met, the INVITE is permitted into the system for processing:

The ingress conditional cac admit in the SIP profile on the ingress realm, SIP interface, session agent parameter is set to enabled
The con-cac-tag sip config option is configured to the same value as the received Require header’s option tag
The call is a candidate for media-release

The call is considered a candidate for media-release on the second system (indicated by the ingress conditional cac admit parameter is set to enabled) when either the ingress or egress realms have any of these parameters set to disabled:

mm-in-realm
mm-in-network
mm-same-ip
mm-in-system

and the following parameter is set to enabled:

msm-release

If the call, as received by the second system is not considered a candidate for release, the INVITE or UPDATE is failed with a 503 Insufficient Bandwidth message.

After the INVITE has been processed by the Oracle® Enterprise Session Border Controller, the Require: header is removed upon egress from the system.

The following diagram shows the two-system scenario: