Before invoking a provisioned originating or terminating sequenced application, Session Manager checks for the value of the Enable Media Filtering flag of the application.

• If the flag is set, Session Manager applies application filtering based on the provisioned media attributes conditions and the media types requested in the SDP. Session Manager invokes the sequenced application only if it passes the filter condition.

• If the flag is not set, Session Manager unconditionally invokes the sequenced application.

Session Manager applies the media based filtering for both orig-side and term-side applications.

For filtering the requests, Session Manager compares the SDP of the SIP request against the following attributes of the sequenced application: Audio, Video, Text, MatchType, and “If SDP Missing”.

The following table shows some of the possible examples for analysis of the media based filtering treatment:

Audio	Video	Text	MatchType	If SDP Missing	Description
Y	Y	Not Only	Exact	Allowed	Enables: {A,V,T} , {A,V} and request with no SDP only.
Y	Y	Not Only	Exact	Skip	Enables: {A,V,T} and {A,V} only. (Does not allow requests without SDP)
N	N	Not Only	Exact	Allowed	Invalid combination.
N	Not Only	Not Only	Not Exact	Skip	Invalid combination. At least one attribute must be Yes.
Y	Y	Not Only	Not Exact	Skip	Enables: {A}, {V}, {A, V}, {A,T}, {V, T}, {A,V,T}
Y	N	Not Only	Not Exact	Skip	Enables: {A} {A,T}

For an application with the Mandatory condition in an application sequence

If the Enable Media Filtering flag is enabled for an application, Session Manager applies application filtering based on media irrespective of the Mandatory condition defined for the application.

For example:

1. Setup details

   • An application sequence vector seq-vector-abc consists of three applications app-a, app-b, and app-c in sequence.

   • Only app-a and app-b have the Mandatory conditions defined.

   • The media-based applicable filtering is enabled for seq-vector-abc. app-a and app-c support audio whereas app-b does not support audio.

2. Call processing details

   Upon receiving an originating audio request from a user of seq-vector-abc, Session Manager removes app-b from the list based on the media attribute filter processing. Even the Mandatory condition is defined for app-b, Session Manager does not invoke app-b because app-b does not meet the media attribute filter condition. Session Manager invokes app-a followed by app-c in the sequence. If the request fails when Session Manager invokes app-a, Session Manager does not proceed with the request because app-a has the Mandatory condition.

In survivable condition

When in the survivable mode, for requests that either originate from or are targeted to the branch SIP endpoint and meet the media attribute filter conditions, Branch Session Manager invokes the SRS as the sequenced application. If the request does not meet the filter condition of SRS, Branch Session Manager skips the sequenced application invocation step.