Calling Name Presentation
Calling Name Presentation (CNAP) is a supplementary telecommunications service that enables the called party to receive and display the name information associated with the calling party's telephone number during call setup for incoming calls.[1] Standardized by the 3rd Generation Partnership Project (3GPP) in TS 22.096, it applies to all circuit-switched bearer services except Short Message Service (SMS), and is invoked automatically by the network when name data is available.[1] The service supports names up to 80 characters in length and includes presentation indicators, such as "presentation restricted" if the caller has invoked Calling Line Identification Restriction (CLIR) or "name not available" otherwise.[1] In practice, CNAP operates by querying centralized databases maintained by network operators to retrieve the caller's registered name, which is then transmitted via signaling protocols like SS7 or SIP in modern networks.[2] It interacts with related services, including CLIR (which takes precedence to withhold the name) and call forwarding (where the original caller's name is preserved unless restricted).[1] While the core functionality is defined internationally, implementations vary by region; in North America, it is commonly known as Caller Name Delivery (CNAM) and relies on a shared national database for landline and mobile numbers.[3] Globally, CNAP has been deployed in various countries to improve call security and reduce spam, with recent expansions in regions like the Middle East and Asia.[2] For instance, in India, the Telecom Regulatory Authority of India (TRAI) approved its nationwide rollout in October 2025, mandating verified names linked to SIM registration documents to combat fraudulent calls, with pilots underway and full implementation expected by March 2026.[4][5] The service requires subscription by the called party for automatic activation and display on compatible devices, with callers able to restrict name presentation via CLIR.[1]Definition and Functionality
Core Concept
Calling Name Presentation (CNAP) is a telecommunications service that retrieves and displays the name associated with the calling party's telephone number on the recipient's device during an incoming call.[6] Standardized by the 3rd Generation Partnership Project (3GPP) in TS 22.096, this functionality operates within telephony networks to provide alphanumeric caller identification, typically appearing alongside or in lieu of the phone number in the caller ID field.[1][7] By associating names with numbers through centralized databases, CNAP extends beyond traditional numeric-only displays to offer more contextual information about the caller.[8] CNAP represents the broad international term for this name delivery capability, while in the United States, the equivalent service is termed Caller Name Delivery (CNAM), a standardized variant embedded in the country's public switched telephone network.[9] Both terms describe the same core objective of name-based caller presentation, though implementations may vary by region due to differing network architectures.[10] The service aims to combat spam, scams, and unwanted calls by presenting names tied to identities from telecom operator databases, thereby empowering recipients to assess call legitimacy before answering.[11] This enhances overall user protection and call management, as names foster greater trust in incoming communications compared to anonymous or spoofed numbers.[7] A practical example involves a call from a business line: instead of showing only a generic number like (555) 123-4567, the recipient's screen might indicate "ABC Bank Customer Service," enabling quick identification of legitimate entities.[12]Operational Mechanism
Calling Name Presentation (CNAP), also known as Caller Name Delivery (CNAM) in some regions, operates through a real-time database lookup mechanism triggered by incoming calls in telephony networks. When a call is placed, the caller's phone number, known as the Calling Line Identification (CLID), is transmitted through the network to the recipient's carrier. The terminating carrier's switch then initiates a query to a centralized Line Information Database (LIDB) or equivalent name database to retrieve the associated caller's name, which is pulled rather than pushed by the originating network.[13][14] The operational flow proceeds as follows:- Call Initiation: The caller dials the recipient's number, and the call is routed via the originating carrier's network, including the CLID in signaling messages.
- Query Trigger: Upon reaching the terminating carrier's switch, a real-time database "dip" is performed using the CLID to search the LIDB for the registered name. In international CNAP implementations, names can be up to 80 characters per 3GPP TS 22.096, while in US CNAM, they are typically limited to 15 alphanumeric characters.[1][13][14] This query occurs in milliseconds to avoid call setup delays.
- Response Retrieval: If a match is found, the LIDB returns the name; otherwise, no name or a default indicator is provided. The response is integrated into the call signaling.
- Name Transmission and Delivery: The retrieved name is forwarded to the recipient's device alongside the CLID, enabling display during the ringing phase.[6]