Contact center terms💡
P-Asserted-Identity
Find out how PAI ensures secure caller identification and what role it plays in modern telecommunications.
What is PAI?
PAI (P-Asserted-Identity) is a SIP header field (Session Initiation Protocol) that is used within trusted networks to reliably transmit the identity of the caller. In contrast to the general "From" information, which can be easily manipulated, the PAI header is used to authenticate the actual sender number - for billing purposes or routing decisions, for example. The PAI header is generally only used between trusted network partners (e.g. carriers) and is usually not visible to the end user.
Function and purpose of PAI
The main purpose of PAI is the secure and reliable transmission of caller identity in SIP-based communication systems. It makes it possible to uniquely identify the actual call number of a subscriber, even if this is not to be displayed publicly (e.g. in the case of a suppressed number or central outbound routing). This information is only passed on within trusted networks and is generally not visible to the called subscriber. Access to this data externally is only possible for certain authorized authorities, such as emergency services, which can determine the caller's location in emergencies.