PAI (P-Asserted Identity) Header
A P-Asserted-Identity (PAI) header field is used on the SIP Private Networking interface to carry identity information. The number in the PAI header field shall be a fully qualified number. It shall be a private number if the Srx/Main/OutGoingCallingPartyNumberType RTP variable is set to 1 (private) or 2 (unknown) and shall be a public number if the RTP variable is set to 0 (public). The information within the PAI header field can be used by the receiver for display purposes, feature handling, and billing features. .
In order to provide SIP-Q equivalent operation, the receipt and sending of PAI header field must be supported on the SIP Private Networking interface in the following requests:
INVITE, re-INVITE, UPDATE w/o SDP
and responses: 8X, 200 OK, 3XX, 480, 486
A From header field is used on the SIP Private Networking interface to indicate the calling party. The originating Telephony Control Server system may remove the original identity information from the received From header field from the client and may insert name and number information from the database. This header field always contains the public identity of the calling party. If the calling party does not have an external DID number, the BG main directory number is substituted. This information can be used by the receiver for display, billing. The calling party number may be sent to the public network. The From header field shall not be anonymized by the originating Telephony Control Server. Instead the terminating Telephony Control Server shall anonymize the From header field based on the value of the Privacy header field. This applies to all cases where the calling party activated (either through configuration or via access code) identification restriction.
A Privacy header field is used on the SIP Private Networking interface to indicate whether the number and name in the PAI and the From header fields are restricted.
The number and name information should not be anonymized until sent on the SIP subscriber interface or towards an untrusted SIP endpoint. Telephony Control Server uses the Privacy header field value "id" to indicate that the name and number in the PAI and From header fields are restricted.
When only the name is restricted (i.e. the number is not restricted), then the name is anonymized (i.e. set to "anonymous") at local Telephony Control Server before sending the header field on the SIP Private Networking interface.
When only the number is restricted (i.e. the name is not restricted), then the Privacy header field must be set with value "id" to indicate restriction of the number. Unfortunately, this means that though the name is not restricted it will be anonymized at the Telephony Control Server interworking the SIP Private Networking to an untrusted SIP endpoint or to the SIP-Q Private Networking interface.
PAI and Privacy header fields are used during most feature operations. When an endpoint is configured for SIP Private Networking, configuration of Full Privacy support (i.e. 'trusted') SIP endpoint is implied. This means that even if it is not explicitly configured, this setting is assumed by the Telephony Control Server.
A To header field is used on the SIP Private Networking interface to indicate the original called party to a called subscriber. No constraints on content (any URI scheme is supported).
Parent topic: Attributes for a SIP Endpoint