The R-IM-SSF is triggered in the IN by the InitialDP initial request event.

Triggering the R-IM-SSF

  1. The R-IM-SSF uses the ServiceKey of the InitialDP event to find the address of the external SIP application server.

  2. The R-IM-SSF builds an INVITE (and the SDP portion) and invokes the SIP application server.

Tip The R-IM-SSF requires that the InitialDP has at least a ServiceKey, a CallingPartyNumber, and a CalledPartyNumber (or CalledPartyBCDNumber for CAP O-BCSM triggers).

The R-IM-SSF manages a number of profile tables that it uses to trigger a SIP application. The rimssf-configuration-profile-table contains global configuration information. This profile table typically contains only one profile, as the R-IM-SSF uses the same configuration information for all calls.

The R-IM-SSF uses records from three other configuration profile tables to determinate how to build the outgoing INVITE and which SIP application server to send it to:

  • rimssf-service-configuration-profile-table — external SIP application service configuration

  • rimssf-invite-builder-profile-table — information to populate the headers in the INVITE message

  • rimssf-sdp-builder-profile-table) — information to build the SDP portion of the INVITE.

The records in these three tables are indexed by service key. The ServiceKey from the incoming InitialDP is used to find the appropriate configuration information for the call.

Warning

If:

  • the InitialDP does not contain the minimum required fields …​ or …​

  • there isn’t a record corresponding to the ServiceKey in one or more of the configuration profile tables

…​then the R-IM-SSF does not attempt to trigger a SIP application server and allows the call to proceed (by responding to the switch with a Continue in a TC-End).

Finding the SIP-AS

The R-IM-SSF searches for a record in the rimssf-service-configuration-profile-table that corresponds to the ServiceKey from the InitialDP. The R-IM-SSF uses the information in the record to determine the address of the external SIP application server.

Field Description 
ServiceKey

The ServiceKey value from the InitialDP.

 
SipAsAddress

The SIP application server address (in the form address:port).

 
AnnouncementPrefix

A prefix to check for in the INVITE received from the SIP-AS that may indicate user interaction is required.

 
AnnouncementMode

Indicates whether user interaction mode is direct, assisting using separate EstablishTemporaryConnection operation fields, or assisting combining parameters into a single ETC operation field.

 
ResetTimerTimeout

Timeout used for ResetTimer operations. If 0 then ResetTimer operations are not sent by the R-IM-SSF during user interaction.
Tip See [2 Configuring R-IM-SSF Subscription Information] for the sis-console commands to use to manage the rimssf-service-configuration-profile-table.

Building the INVITE

The R-IM-SSF searches for a record in the rimssf-invite-builder-profile-table that corresponds to the ServiceKey from the InitialDP. The R-IM-SSF uses the information in the record to build the INVITE message it sends to the external SIP application server.

Field Description 
ServiceKey

The ServiceKey value from the InitialDP

 
IsSipURIUsed

Whether a SIP URI or Tel URL should be used to create initial INVITE

 
Transport

The SIP Transport used towards the service: udp, tcp, or udp/tcp

 
AccessParameter

The name of a parameter of the Route that should be used to distinguish between originating and terminating triggers

 
AccessParameterOrigValue

The value of the AccessParameter parameter that indicates an originating trigger

 
AccessParameterTermValue

The value of the AccessParameter parameter that indicates a terminating trigger

 
HasPAccessNetworkInfoHeader

If the initial INVITE should include the optional P-Access-Network-Info header

 
DefaultCgi

The default CGI parameter for the P-Access-Network-Info header; used when LocationNumber is not present on the InitialDP received

 
HasPChargingVectorHeader

If the initial INVITE should include a P-Charging-Function-Addresses header

 
HasCCF

If the initial INVITE includes the optional CCF parameter in the P-Charging-Function-Addresses header

 
CCF

CCF parameter for P-Charging-Function-Addresses header

 
HasCCF

If the initial INVITE includes the optional ECF parameter in the P-Charging-Function-Addresses header

 
ECF

ECF parameter for P-Charging-Function-Addresses header

 
ExpiresHeader

The Expires header value used for the initial INVITE

 
HasMinSEHeader

If the initial INVITE should include an optional Min-SE header

 
MinSEHeader

Min-SE header value

 
HasPCalledPartyIDHeader

If the initial INVITE should include an optional P-Called-Party-ID header

 
HasSessionExpiresHeader

If the initial INVITE should include an optional Session-Expires header

 
SessionExpiresHeader

Session-Expires header value

 
HasSupportedHeader

If the initial INVITE includes optional Supported header

 
SupportedHeader

Values to include in the Supported header

 
UserAgentHeader

User-Agent header value for initial INVITE
Example configuration …​ …​results in: 
ServiceKey
 
23
 
IsSipURIUsed
 
true
 
Transport
 
udp
 
AccessParameter
 
call
 
AccessParameterOrigValue
 
orig
 
AccessParameterTermValue
 
term
 
HasPAccessNetworkInfoHeader
 
true
 
DefaultCgi
 
111111111
 
HasPChargingVectorHeader
 
true
 
HasCCF
 
false
 
CCF
 






HasCCF


false






ECF








ExpiresHeader


360






HasMinSEHeader


true






MinSEHeader


2120






HasPCalledPartyIDHeader


false






HasSessionExpiresHeader


true






SessionExpiresHeader


360






HasSupportedHeader


true






SupportedHeader


timer,replaces






UserAgentHeader


rimssf-useragent-inv-builder











INVITE sip:123456789@opencloud.co.nz SIP/2.0
From: <sip:+351987654321@opencloud.co.nz>;tag=g5qB7w
To: <sip:123456789@opencloud.co.nz>
Call-ID: n1O3nxW0T6iW5P5P3-TmjQ
CSeq: 63062 INVITE
Max-Forwards: 70
Via: SIP/2.0/UDP 192.168.62.102:5060;oc-node=101;rport;branch=z9hG4bKFAdZ7Kn7vR364EMwd73ABA;ext
Via: SIP/2.0/UDP 192.168.62.102:5060;oc-node=101;rport;branch=z9hG4bKTvm5BnH1zYrsbC0ZDLpWdw
Contact: <sip:Ai-cCypiu+hkF35L3H~FqyAw@192.168.62.102:5060;oc-node=101;transport=udp>
Route: <sip:192.168.62.102:5070;lr;transport=udp;call=orig>
Route: <sip:Ai-cCypiu+hkF35L3H~FqyAw@192.168.62.102:5060;oc-node=101;lr;transport=udp>
P-Asserted-Identity: <tel:+351987654321>, <sip:+351987654321@opencloud.co.nz>
Supported: timer, replaces, 100rel
Allow: INVITE, BYE, CANCEL, ACK, PRACK, UPDATE
P-Charging-Vector: icid-value=1283143839977;orig-ioi=opencloud.co.nz
P-Access-Network-Info: 3GPP-GERAN;cgi-3gpp=111111111
Expires: 360
Session-Expires: 360
Min-SE: 2120
User-Agent: rimssf-useragent-inv-builder
...

















Tip


See Configuring R-IM-SSF Subscription Information for the sis-console commands to use to manage the rimssf-invite-builder-profile-table.














Building the SDP portion






The R-IM-SSF searches for a record in the rimssf-sdp-builder-profile-table that corresponds to the ServiceKey from the InitialDP. The  R-IM-SSF uses the information in the record to build the SDP portion of the INVITE message it sends to the external SIP application server.












Field
Description







ServiceKey




The ServiceKey value from the InitialDP








SDPNetworkType




The SDP network type








SDPAddressType




The SDP address type








SDPMediaType




The SDP media type








SDPMediaFormat




The SDP media format








SDPMediaProtocol




The SDP media protocol








SDPFmtpAttribute




The SDP Fmtp attribute












SDPRtpmapAttribute








The SDP Rtpmap attribute




OrigPort

















Example configuration…​
…​results in
















ServiceKey


23






SDPNetworkType


IN






SDPAddressType


IPV4






SDPMediaType


audio






SDPMediaFormat


[0, 8, 18]






SDPMediaProtocol


RTP/AVP






SDPFmtpAttribute


96 0-15,66,70






SDPRtpmapAttribute


96 telephone-event/8000






OrigPort


49170











INVITE sip:123456789@opencloud.co.nz SIP/2.0
From: <sip:+351987654321@opencloud.co.nz>;tag=g5qB7w
...
User-Agent: rimssf-useragent-inv-builder
Accept: application/sdp
Content-Type: application/sdp
Content-Length: 182

v=0
o=+351987654321 3 3 IN IP4 192.168.62.102
s=oc-node=101
c=IN IPV4 192.168.62.102
t=0 0
m=audio 49170 RTP/AVP 0 8 18
a=fmtp:96 0-15,66,70
a=rtpmap:96 telephone-event/8000

















Tip


See Configuring R-IM-SSF Subscription Information for the sis-console commands to use to manage the rimssf-sdp-builder-profile-table.











                        

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