Method of restoring the correct cell sequence, particularly in an ATM exchange, and output unit therefor

US5173897A · kind A · utility

Assignee

• Alcatel N.V. · NL

Inventors

• Karl Schrodi · Bad Buchau, DE
• Gert Eilenberger · Stuttgart, DE
• Stefan Wahl · Hemmingen, DE
• Bodo Pfeiffer · Bad Buchau, DE
• Bozo Cesar · Kornwestheim, DE

Key dates

• Filing date: Dec 19, 1990
• Grant date: Dec 22, 1992
• Expiry date: Dec 19, 2010

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04L2012/565
• WIPO field: Digital communication
• WIPO sector: Electrical engineering

Abstract

To be able to load an ATM switching network as efficiently as possible, the successive cells of one and the same connection are routed to the output by as many different paths as possible; however, mutual overtaking of successive cells must be avoided or corrected. Each cell is held at the output until it is certain that no older cell can be buffered in the switching network. Before the cell is passed on, a check is made to determine whether the cells received from the switching network later include an older cell which must be passed on before that cell. At the input end, consecutive numbers ("Sequence Numbers") are allocated to the cells. A buffer (1) at the output end is operated, at least in part (1 . . . d), in the manner of a shift register, thereby introducing a predetermined delay. Prior to the output of a cell, at least the shift-register-like portion of the buffer is examined as to whether a cell written in later is to be put out earlier: if so, the two cells are interchanged.