Channel allocation method for a ring network

摘要

A telecommunication network having a number of stations, such as telephone sets, which are connected to a ring server station (8) by means of a token ring. Each station comprises a receiver (10) for receiving a Time Division Mutiplex (TDM) frame and a transmitter (60) for transmitting the frame to the token ring. The structure of the frame comprises a a first START field. A second TOKEN field which can carry three distinctive states: a first value (FF) representative of the token being free, a second value (00) representative of the token being busy and a third value (AA) being controlled by said ring server station (8). The TDM frame further comprises a third SNUM field representative of a slot number and a fourth and fifth field which are respectively representative of an identification address of an emitting and a receiving station. A additional SIGNA field is representative of the signalling message to by transmitted to the server station and is followed by a number of n TDM slots which are affected for the actual communication of data within the TDM frame. The station further comprises means (40, 130, 260, 270, 190) under control of a processor (200) for detecting the presence of said first value into said TOKEN field and for replacing said first value (FF) by said second value (00) in order to inform said ring server station (8) that the token is requested. Additionally, the station has means (40, 130, 260, 270, 190) for substituting the contents of said fourth ADDR_E field and said fifth ADDR_R field with values generated under control of said processor characterizing the identity of the calling and the called station. The occurrence of the busy token is monitored and followed by an analysis of the contents of the ADDR_E and ADDR_R field in order to determine the identity of the calling and the called station. The contents of the second TOKEN field is then substituted by the token ring server (8) in order to inform the calling and the called station that the communication is allowed and can be established. The ring server also substitutes the contents of the third SNUM field via a value which is representative of the slot number which is assigned to the communication between the calling and the called party. <MATH>