name: TNA
full_form: Trusted Node Authentication
context: The main use case for TNA is to provide access to the IMS network for legacy or IMS enabled equipment when connected via a CS access domain as defined for ICS (see TS 23.292 [50]). TNA relies on the following assumptions: - The trusted node can be in either the home or visited network - The trusted node provides sufficient means for authentication in the CS access domain - The trusted node provides interworking between the IMS domain and the CS access domain The authentication flow is depicted below in Figure U.1. Figure U.1 Trusted Node performs registraton on behalf of the UE The details of the signalling flows are as follows: 1. CS attach (UE A to Trusted Node) As a result of some stimulus, UE A performs CS attachment toward the CS network 2. Authentication and Update Location (MSC/VLR to HLR/HSS) The CS network performs standard CS location update, authentication and obtains subscriber data. 3. CS attach accept (MSC to UE A) The CS attach request is accepted by the network, an
description: Trusted Node Authentication (TNA) is a protocol used for authenticating user equipment (UE) in the IMS network when connected via a Circuit Switched (CS) access domain. It relies on a trusted node that provides sufficient means for authentication and interworking between the IMS domain and the CS access domain.
explanation: The text describes TNA as a mechanism governing the interaction between user equipment, a trusted node, and the IMS network for authentication purposes. This clearly defines TNA as a set of rules and procedures dictating how these entities communicate, thus classifying it as a protocol.
section_title: U.2	Use case and detailed description
biotag_Context: O,O,O,O,O,B-Protocol,O,O,O,O,O,O,B-Network,O,O,O,O,B-Network,O,O,O,O,O,O,B-Mode,O,O,O,O,O,B-Specification,O,B-Specification,O,O,B-Protocol,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,B-Mode,O,O,O,O,O,O,O,O,O,O,B-Network,O,O,O,B-Mode,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,B-Device,O,O,O,O,O,O,O,O,O,O,B-Mode,O,O,O,O,O,O,O,O,O,O,O,O,B-Device,O,O,B-Mode,O,O,O,B-Mode,O,O,O,O,O,O,O,O,O,O,B-Mode,O,O,O,B-Mode,O,O,O,O,O,O,O,O,B-Mode,O,O,O,O,B-Device,O,O,B-Mode,O,O,O,O,O,O,O,O
biotag_Description: B-Protocol,I-Protocol,I-Protocol,O,O,O,O,O,O,O,O,O,O,O,O,B-Network,O,O,O,O,O,B-Mode,I-Mode,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,B-Network,O,O,O,B-Mode,O,O