SIP P-Charging-Vector Header

 icid-value(IMS Charging ID)

This parameter is mandatory and provided by the network. The icid-value identifies a dialog or transaction outside a dialog. The icid-value is used to correlate charging records and is a globally unique value.

orig-ioi (Originating Inter Operator Identifier)

This parameter is optional and provided by the network. This parameter represents the network responsible for the charging records in the originating part of the session or standalone request.

term-ioi (Originating Inter Operator Identifier)

This parameter is optional. This parameter represents the network responsible for the charging records in the terminating part of the session or standalone request.

icid-generated-at  

This parameter is optional and provided by the network. This parameter contains the host name or IP address of the proxy that generated the icid-value

• The P-Charging-Vector header containing the parameters icid-value and orig-ioi is interworked from I-CSCF network to the SIP B leg in the INVITE

• The P-Charging-Vector header containing the parameters icid-value, orig-ioi, and term-ioi is interworked back from the B side to the I-CSCF network in the 183 Session Progress and 200 OK INVITE responses. 

• The first 183 Session Progress response from the 2020 SBCis interworked from the B side, and thus contains the P-Charging-Vector header.

• The retransmitted periodic 183 Session Progress responses are generated by the IMG 2020, and thus do not contain the P-Charging-Vector header.

• The retransmitted periodic 183 Session Progress responses are interworked from the SIP B Leg. Since the SIP Network on the B-Leg also follows the I-CSCF -to- SIP B Leg Interface specification, it doesn’t include the P-Charging-Vector header in these periodic responses. Thus the IMG 2020 interworks the periodic 183 Session Progress responses properly without the P-Charging-Vector header.

• The RE-INVITE from the I-CSCF SIP Network side contains the P-Charging-Vector header and is handled locally by the IMG 2020. The 200 OK RE-INVITE response doesn’t contain the P-Charging-Vector header.

• The P-Charging-Vector header is interworked in the BYE message.

• The 200 OK BYE from the SIP B Leg contains the P-Charging-Vector header, but the response on the I-CSCF SIP Network side doesn’t contain any, as it is already sent before.

• The 200 OK BYE from the SIP B-leg is not interworked through the IMG 2020.

• The UPDATE message from the I-CSCF SIP Network side contains the new value icid-value2 and icid-generated-at. These new values override the values in the interworked 200 OK INVITE response from the SIP B Leg.

• The IMG 2020 adds the icid-generated-at parameter to the P-Charging-Vector header in the 200 OK INVITE and BYE messages on the I-CSCF SIP Network side. The icid-generated-at message was saved from the initial UPDATE message.

• The 200 OK INVITE response on the I-CSCF SIP Network side contains the parameter icid-generated-at saved from the UPDATE message.

• The BYE message from the SIP B Leg doesn’t contain the P-Charging-Vector header thus, the IMG 2020 doesn’t add it to the interworked BYE message on the I-CSCF SIP Network side either.

The IMG 2020 interworks the P-Charging-Vector in the BYE message from the I-CSCF SIP Network side to the SIP B Leg. None of the parameters saved from the UPDATE message on the I-CSCF SIP Network side are added. 

• The SIP B Leg sends back the 180 Ringing response without the P-Charging-Vector header.

• The IMG 2020  interworks the 180 Ringing from the SIP B Leg into the 183 Session Progress on the I-CSCF SIP Network side, without a P-Charging-Vector header.

• The 2nd 183 Session Progress on the SIP B Leg is interworked into the 183 Session Progress on the I-CSCF SIP Network side. This 183 Session Progress message contains the P-Charging-Vector header.

If the SIP B-Leg includes the P-Charging-Vector header 180 Ringing response, then the IMG 2020 will include it in its 183 Session Progress response