Patent ID: 6327261
Filing Date: 2001-12-04
Classification: H04L

Abstract:
Process for translating an ATM cell header for the routing thereof over a transmission highway of a communication network via an ATM switch, consisting in having the switch translate the pair (VPI, VCI) contained in the cell header and constituting the ATM address of the cell, the first field VPI identifying a virtual path number and the second field VCI selecting a specified virtual channel within the virtual path, by carrying out successive indexations by means of five tables so as to culminate in an address compression, characterized in that it consists:in allowing a translation of the first field VPI of the header of the cell irrespective of its value by means of a field of the contexts contained in the first table (PMD context table) defining the number of useful bits of the first field VPI,in selecting a first mode of translation (VP switch) or a second mode of translation (VC switch) by means of a field of the contexts contained in the second table (mode selection table) defining the number of useful bits (NBU) of the second field VCI of the cell header, this field consisting of a first field defining a first pointer shift and of a second field defining a second pointer shift,in the second mode of translation (VC switch) in organizing the fifth table (VCI context table) into pages containing the translation values of the pair (VPI, VCI), each page being associated with a specified value of the first field VPI of the header of a cell and each page being addressed by a pointer contained in the fourth gable (table of page pointers), itself addressed by a pointer contained in the second table (mode selection table).