Patent ID: 7184438
Filing Date: 2007-02-27
Classification: H04L,H04Q

Abstract:
1. A method of task management for a routing automaton of a packet switch forming part of a secured packet-switching transmission network and comprising several input ports and several output ports serving as points of access to incoming and outgoing data traffic using physical transmission links externally connected to the packet switch, in the form of transmission signals containing datagrams, said datagrams containing message bits and service bits containing routing instructions used for the definition, for each datagram, of a path known as a “virtual” path to be followed within the network in order to reach its destination, wherein said task management method consists firstly in providing said routing automaton with a table, stored in random access memory, of local descriptors of the virtual paths taking the packet switch considered, a local descriptor assigned to a given virtual path containing a distribution profile listing the output ports of the packet switch considered used by the virtual path concerned, a reception profile listing the input ports of the packet switch that can be used by the virtual path concerned, information on the shape and bit-rate constraints imposed on the datagrams taking the virtual path concerned and chronological information with which to determine the earliest date for a licit arrival of the next datagram taking the virtual path concerned and, furthermore, in sharing the processing time of said routing automaton in a repetitive sequence of time slots, some of which are distributed between the different input ports, each of them being individually assigned to a particular input port and being reserved for operations forming part of the routing processing of the datagrams received by its assigned input port, this processing consisting, for a datagram, of: the reading, in the random access memory, of the virtual path local descriptor assigned to the datagram received, identified in the table of local descriptors by means of the service data drawn from the datagram received, the performance, on the datagram, of the anti-congestion safety verification operations in taking account of its date of reception by the packet switch, the identity of the input port that was used by it to access the packet switch and the information contained in the local descriptor read, either the rejection of the datagram being processed when one of the preceding verification operations is negative, or, when all the previous verification operations are positive, the updating of the chronological information used to determine the earliest date for a licit arrival of the next datagram taking the virtual path concerned and the proposing of the datagram being processed to the output ports listed in the distribution profile of the read local descriptor, with a view to the re-sending of this datagram by its output ports.