METHOD AND DEVICE FOR SWITCHING BETWEEN AGENTS

1 . A method of communication between agents in an interconnection system comprising at least three elements, the method comprising:

sending a message destined for a determined receiver agent by a message initiator agent over a point-to-point interconnection network;

detecting an error and, if an error is actually detected, the said message is marked as being erroneous, wherein the error detection is performed by an intermediate agent of the point-to-point interconnection network; and

forwarding the message to the said determined receiver agent if the said forwarding is possible and, if the said message is marked as being erroneous, the receiver agent formulates an error message and sends it to the initiator agent so as to warn the said initiator agent of the presence of an error, wherein if the message cannot be forwarded to the said determined receiver agent from the said initiator agent, then the message is marked as being erroneous and forwarded to another receiver agent linked to the said interconnection network.

2 . The method according to claim 1 , wherein the said message is marked as being erroneous by the setting of at least one bit of the said message.

3 . The method according to claim 1 , wherein the receiver agent detects the marking of the message before responding to the initiator agent.

4 . The method according to claim 3 , wherein the detection of the said marking of the message disables the normal processing of the message by the receiver agent.

5 . The method according to claim 1 , wherein the other receiver agent is a determined receiver agent.

6 . The method according to claim 1 , wherein the said other receiver agent receives all the messages that cannot be forwarded from the said initiator agent.

7 . The method according to claim 1 , wherein if the said determined receiver agent belongs to a zone of restricted access wherein the said message does not have authorization to enter, then the said message is marked as being erroneous and then sent to the said determined receiver agent notwithstanding the access restriction.

8 . A system for communication between agents in a point-to-point interconnection system, comprising at least three elements, the system comprising:

at least one initiator agent capable of dispatching at least one message destined for at least one determined receiver agent, at least one intermediate agent capable of forwarding at least one message to at least one determined receiver agent, at least one receiver agent capable of receiving at least one message originating from said at least one initiator agent via said at least one intermediate agent, means of error detection and means of erroneous message marking, the receiver agent comprising means for formulating an error message and means for sending the error message to the initiator agent so as to warn the said initiator agent of the presence of an error, wherein at least one intermediate agent includes means of error detection and means of erroneous message marking, wherein at least one intermediate agent includes means for forwarding an erroneous marked message to another receiver agent linked to the interconnection network, the said forwarding means being active if the message may not be forwarded to the said determined receiver agent from the said initiator agent.

9 . The system according to claim 8 , wherein the means of erroneous message marking include a means of setting at least one determined bit of the said message.

10 . The system according to claim 9 , wherein the receiver agent includes means for disabling the elaboration of a response to an erroneous message.

11 . The system according to claim 8 , wherein the receiver agent includes means for disabling the elaboration of a response to an erroneous message.