Table 15.2.1.1 below indicates the procedures used between the (G)MSC server and the MGW in the Mc interface. These procedures are defined in clause 16.2 of TS 23.205.

The clauses below indicate the procedures used between the (G)MSC server and the MGW in the Mc interface that are specific for a SIP-I based Nc network. The procedures are logical, i.e. message identifiers are not part of the protocol. Several logical procedures can be combined into one H.248 command in order to perform required transactions. If several logical procedures are combined into one H.248 command, only one context/context request and only one bearer termination/bearer termination request is sent in the H.248 command. All the procedures below describe a successful operation. If the procedure is rejected, a Command Reject is sent back to the entity that sent the command request. Each Information Element, IE, is marked as (M) Mandatory, (C) Conditional or (O) Optional. A mandatory information element shall always be present. A conditional information shall be present if certain conditions are fulfilled; if those conditions are not fulfilled it shall be absent. An optional information element may be present or absent, at the discretion of the application at the sending entity. This categorisation is a functional classification, i.e., stage 2 information and not a stage 3 classification to be used for the protocol. The stage 2 and stage 3 message and information element names are not necessarily identical.