Method and apparatus for communication of ATM cells in a ring network

摘要

A method and apparatus for allowing communications of Asynchronous Transfer Mode (ATM) cells in a ring network is disclosed. The ring comprises at least one station A (101), a second station B (102) and a third station (001) which operates as a ring server. The communication within the ring is based on a specific frame structure having two delimiters, a frame starting and a frame ending delimiters. The frame further comprises a TOKEN field used by each station for requesting an access to the next frame which will be available in the ring. The TOKEN includes a first PRIORITY field which is continuously updated by each station when the frame circulates with the ring. This is performed by the replacement of value carried by the PRIORITY field by the own PRIORITY value of the station when the latter appears to be superior than the former. Additionally, the frame has an ACCESS field including a first LEVEL field which is used by each station, in response to a comparison with the value carried by said priority field of said ACCESS field and the internal priority of the ATM cell which station wishes to transmit, for accessing the frame. The frame is then completed with an TM cell for allowing the transport of control or data via the communicating ring.