FR2823041A1 - Serial bus packet handling procedure purges link layer without marker transmission is fast - Google Patents

Abstract

A serial bus (1-5) packet handling procedure inserts a marker packet in a packet stream to start a mode change to local processing in a gateway (6-9) transmission (10-17) unit for previous packets with deletion of marker and processed packets without transmission.

Description

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Method, application, devices and modules for managing data packets in a communication node

 The present invention relates to the field of communication networks, and in particular to the transmission of data in a high-speed communication network.

 More specifically, the invention relates to the management and processing of the packets present in a communication node, when the operating conditions of the network are modified.

 In a network environment, events such as network topology changes require specific processing, which impacts the data packets to be transferred.

ajout d'au moins un dispositif sur le réseau ; et/ou mise à jour d'informations de routage. Thus, for example, the IEEE 1394 standard provides for topology changes associated with the following operations resulting in bus resets called reset bus: loss of connection of part of the network following the removal of at least one bridge portal (a portal being here a connection between a bridge and a bus
IEEE 1394);

adding at least one device on the network; and / or updating routing information.

 The IEEE standard is specified in the following documents issued by the IEEE (Institute of Electrical and Electronics Engineers): P1394. 1 Draft Standard for high performance serial bus bridges, or in French P1394.1 Provisional standard for high-performance serial bus bridges published in version 0.14 in December 2000 by the IEEE; - IEEE Std 1394-1995, Standard for High Performance Serial Bus or French IEEE Std 1394-1995: Standard for a high performance serial bus; and

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   IEEE Std 1394a-2000, Standard for High Performance Serial Bus (Supplement), or IEEE Std 1394a-2000, Standard for High Performance Serial Bus (Supplement).

 Note that the IEEE 1394 standard defines three protocol layers below the application layer: - a physical layer; a bond layer; and - a transaction layer.

 Thus, according to this example, the packets can be in three possible states, depending on the layer considered: the packets awaiting transfer (the application requests a transmission); - Packets put in a queue by the transaction layer before being sent to the link layer; and - packets in transit in the link layer, put in a queue for transmission to the physical layer.

 For networks comprising buses according to the IEEE 1394 standard, after the generation of a bus reset signal, asynchronous packets (as defined in the IEEE 1394 standard under the name of asynchronous sub-actions) must be processed. according to certain criteria. Thus, the IEEE 1394 standard requires different processing of packets according to their origin and / or destination: packets to and from a local bus must be discarded while packets to and / or from a remote bus will be put in a queue for later transmission.

 Packets awaiting transfer (first case) or put in a queue by the transaction layer (second case) can be discarded according to a conventional method of queue management (software).

 On the other hand, packets already in transit in the link layer (third case) require unconventional specific processing. These packets put in a queue for a delayed transmission, these packets are usually:

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- already stored in an ATF memory (from Asynchronous English)
Transmit FIFO or FIFO memory (First In First Out or memory where the first stored data are the first transmitted) of the link layer which is used to transmit the asynchronous packets); or - already taken into account by a direct memory access controller (or
DMA allowing fast transfer between two memories, the controller using the source address of the first data to be transferred, its destination address and the size of the block to be transferred) for storage in an ATF memory.

 It is known in the prior art, the TSB12LVO1A component of the company TEXAS INTRUMENTS (registered trademark) which is a component of the IEEE 1394 link layer.

 The link layer contains at least one Asynchronous Transmission FIFO (ATF) type component.

Upon receipt of bus reset information, this component inhibits its asynchronous transmission means by putting into play a TxA-En signal. This signal has a representative bit in the control register (CONTROL REGISTER), which is accessible by a software command.

In addition, the software command can generate the ATF dump using write access to the FIFO CONTROL register.

 In summary, the TSB12LV01A component inhibits the asynchronous transmission means upon receipt of a bus reset detection signal and provides the ability to clear the contents of the ATF prior to reactivation of the asynchronous transmission means. It is the software control that is responsible for ensuring that there are no more packets in the DMA controller queue.

 A disadvantage of this prior art technique is that it is slow in its execution.

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 In addition, following a change in the operating mode of the network, the transmission of new data packets is relatively slow to establish.

 The invention in its various aspects is intended to overcome these disadvantages of the prior art.

 The invention also aims to optimize the processing of packets in transit in a communication node according to specific criteria, especially when the data rate on the physical layer is high (for example greater than 10 Mbps).

 The invention also aims to allow the transmission of data packets addressed to a local bus during a quarantine period prohibiting the transfer of data packets from and to distant buses.

 Another object of the invention is, of course, to provide a method for managing packets in transit, which is reliable and efficient, simple and inexpensive to implement.

 These objectives as well as others which will appear later are achieved according to the invention, using a packet management method that can be processed according to at least one first mode of transmission and at least one mode of transmission. local processing, in a communication node of a communication network, remarkable in that the packets are inserted chronologically in at least one packet stream and in that it comprises a step of inserting a marker in each stream of packets, when a mode change is detected, so that, following the detection of the mode change, the packets remaining in the stream of packets before the marker are processed according to one of the local processing modes.

qui peut être continu ou discontinu ; et qui peut être synchrone ou non. It should be noted that the term packet stream is understood here in a broad sense and relates to a stream (or an ordered sequence): containing one or more packets that can be addressed to different recipients;

which can be continuous or discontinuous; and which can be synchronous or not.

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 This stream may, in particular, constitute an input stream in a transmission memory. It can then be assimilated to the contents of this memory.

 According to a particular characteristic, the method is remarkable in that the marker is a particular package of structure.

 According to one particular characteristic, the method is remarkable in that it comprises a step of purging the marker so that it is not transmitted on the network.

 Thus, the invention advantageously allows a similar processing of the protocol data unit type (PDU) packets and marker type packets which simplifies its implementation, operations strictly related to the management. of the flow being identical in both cases.

 Nevertheless, since the marker is used locally in a communication node, it is preferably purged in the communication node so as not to be transmitted over the network. This allows in particular not to unnecessarily clutter the network and / or not to disrupt the network.

- insérés dans le flux de paquets par un moyen de contrôle ; et - mémorisés dans un moyen de transmission ; le moyen de contrôle et le moyen de transmission étant aptes à mettre en oeuvre le premier mode de transmission et au moins un des modes de traitement local. According to one particular characteristic, the method is remarkable in that the packets and the markers are:

- inserted into the packet stream by a control means; and - stored in a transmission means; the control means and the transmission means being able to implement the first mode of transmission and at least one of the local processing modes.

 Thus, the invention advantageously makes it possible to implement a step of inserting packets and markers into the packet stream and a storage step in the transmission means, the control and transmission means being able to easily discern the mode to be transmitted. apply to packages.

 According to one particular characteristic, the method is remarkable in that it comprises a step of managing a direct access to the memory allowing the

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 transferring packets and markers inserted in the packet flow from the control means to the transmission means.

 Thus, the invention advantageously allows a quick and easy transfer to implement packets and markers, the control means to the transmission means.

prendre en compte les différents modes ; ou, au contraire, se faire de manière transparente vis-à-vis des différents modes. It is noted that the management of a direct access to the memory can:

take into account the different modes; or, conversely, be transparent to the different modes.

 According to one particular characteristic, the method is remarkable in that a mode change corresponds to a modification of network operation.

 According to a particular characteristic, the method is remarkable in that the mode change belongs to the group comprising: resets of at least part of the network; - modifications of the network topology; and changes in packet routing conditions within the network.

 According to a particular characteristic, the method is remarkable in that the mode change is detected by the reception of a corresponding information signal (bus reset).

 Thus, the invention is advantageously implemented during changes in the operation of the network, in particular when receiving an information signal, for example of the bus reset type.

 It should be noted that, according to the invention, the transmission means can advantageously easily determine the non-transmitted packets before receiving an information signal and inserted in the packet stream before the corresponding marker, and thus apply to them a mode of transmission. adequate treatment.

 According to one particular characteristic, the method is remarkable in that the local processing modes belong to the group comprising:

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- un mode de purge totale de tous les paquets prêts à émettre sur le réseau ; et - un mode mixte au cours duquel les paquets prêts à émettre sur le réseau sont purgés ou transmis sur le réseau selon une première règle déterminée.

a mode of total purge of all packets ready to transmit on the network; and a mixed mode in which the packets ready to transmit on the network are purged or transmitted on the network according to a first determined rule.

 Thus, the invention advantageously allows filtering, selective (mixed mode) or not (full purge mode), packets ready to send.

 According to one particular characteristic, the method is remarkable in that a local processing mode is implemented as long as the number of detected mode changes is strictly greater than the number of markers purged by a transmission means.

 Thus, the invention takes into account, preferentially, the detection of successive information signals.

 According to a particular characteristic, the method is remarkable in that the mixed mode is implemented when the network does not allow the transmission of certain packets according to the first determined rule.

According to a particular characteristic, the method is remarkable in that, in the mixed mode, a transmission means implements for each packet ready to transmit: a step of checking transmission authorization criteria; a step of transmitting the packet on the network, if the result of the verification step is positive; and a step of purging the packet that is ready to transmit, if the result of the verification step is not positive
According to one particular characteristic, the method is remarkable in that the transmission authorization criteria belong to a group comprising: packet validity criteria; and packet transmission authorization criteria depending on the state of the network and / or the characteristics of the packet.

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According to one particular characteristic, the method is remarkable in that the step of verifying the transmission authorization criteria comprises taking into account the characteristics of the packet belonging to the group comprising: a source address of the packet; a destination address of the packet; - a network element identifier in the source address of the packet; and a network element identifier in the destination address of the packet.
According to one particular characteristic, the method is remarkable in that according to the transmission authorization criteria, packets to and from a remote bus that is part of the network are not allowed to be transmitted on the network.

 Thus, the invention advantageously makes it possible to optimize the transmission of packets according to rules (in particular from standards such as, for example, the IEEE1394 standard) which authorize or on the contrary forbid the transmission of certain packets.

 According to one particular characteristic, the method is remarkable in that, during the total purge mode and / or during the mixed mode, a control means reinserts the purged packets into the stream of packets.

 Thus, the invention advantageously allows not to lose packets, particularly after the marker.

 According to a particular characteristic, the method is remarkable in that during the total purge mode and / or during the mixed mode, a control means updates at least one field inside the packets according to a second rule determined beforehand. re-insert the purged packets into the packet stream.

 According to one particular characteristic, the method is remarkable in that according to this second predetermined rule, the fields are packet address fields from and / or to a local bus destination.

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 Thus, the invention advantageously allows the updating of packets, (in particular fields that may be obsolete, for example, the physical address fields that can be modified after a change of topology network) without having to completely discard these packets.

 According to a particular characteristic, the method is remarkable in that the control means inserts the purged packets again only if immediate transmission of the packet is authorized on the network.

- un placement du paquet dans une file d'attente de paquets mis de coté si la vérification n'indique pas une autorisation immédiate à transmettre ; et - une étape de détection de changement de mode d'autorisation à transmettre et d'insertion dans le flux de paquets des paquets placés dans la file d'attente de paquets mis de coté. According to a particular characteristic, the method is remarkable in that the control means implements: a verification of each packet to be transmitted, a new insertion of the packet into the packet stream if the verification indicates an immediate authorization to be transmitted;

- placing the packet in a queue of packets set aside if the verification does not indicate an immediate authorization to be transmitted; and a step of detecting a change of authorization mode to be transmitted and insertion in the packet flow of the packets placed in the queue of packets set aside.

- à émettre des paquets pour la transmission dès que cette opération est autorisée. Thus, preferably, the transmission of the packets is optimized so as: - not to block the transmission by inserting into the stream packets that could not be transmitted; and or

- to send packets for transmission as soon as this operation is authorized.

 The invention also relates to an application of the remarkable method in that the communication node is connected to at least one IEEE1394 bus.

 The invention also relates to a packet management device implementing the previously described method and in particular a management device.

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 packets that can be processed according to at least a first transmission mode and at least one local processing mode, in a communication node of a communication network, characterized in that the packets are inserted chronologically in at least one stream of packets and in that the device comprises means for inserting a marker in each packet stream, when a mode change is detected, so that, following the detection of the mode change, the packets remaining in the stream of packets before the marker are processed according to one of the local processing modes.

un moyen de détection d'un marqueur inséré dans chaque flux de paquets, lorsqu'un changement de mode est détecté, de façon que, suite à la détection du changement de mode, les paquets restant dans le flux de paquets avant le marqueur soient traités selon un des modes de traitement local. In addition, the invention relates to a packet filtering module implementing at least part of the previously described method. Since the packets can be processed according to at least a first transmission mode and at least one local processing mode, in a communication node of a communication network, the module is remarkable in that it comprises: means for receiving packets inserted chronologically in at least one packet stream; and

means for detecting a marker inserted in each packet stream, when a mode change is detected, so that, following the detection of the mode change, the packets remaining in the packet stream before the marker are processed according to one of the local processing modes.

 The invention also relates to an IEEE1394 communication node remarkable in that it comprises a device and / or a module as previously described.

 The invention further relates to a bridge for a communication network which is remarkable in that it comprises a device and / or a module as previously described and in that it connects at least two elements of the network.

 In addition, the invention relates to a computer program comprising program code instructions for executing the steps of the packet management method as previously described when the program is run on a computer.

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 The invention also relates to a computer program product comprising program code instructions recorded on a medium usable in a computer, comprising computer readable programming means for performing a marker insertion step in at least one packet stream when a mode change is detected, packets being capable of being processed according to at least a first transmission mode and at least one local processing mode, in a communication node of a communication network and inserted chronologically in at least one of the packet streams, so that, following the detection of the mode change, the packets remaining in the packet stream before the marker are processed according to one of the local processing modes.

 The benefits of applying the method, the packet management device, the packet filtering module, the communication node, the communication network bridge, the computer program and the computer program product are the same. than those of the packet management method, they are not detailed further.

la figure 3 présente le format d'un paquet primaire asynchrone transitant sur le réseau de la figure 1 ; - la figure 4 représente un protocole d'échanges entre différents éléments de la figure 2, avec illustration d'une phase de quarantaine mise en oeuvre ; Other features and advantages of the invention will emerge more clearly on reading the following description of a preferred embodiment, given as a simple illustrative and nonlimiting example, and the appended drawings, among which: FIG. 1 presents a network architecture connecting several buses
IEEE 1394 according to the invention according to a particular embodiment; FIG. 2 partially represents a portal providing the connection between two IEEE 1394 buses illustrated in FIG. 1;

FIG. 3 presents the format of an asynchronous primary packet transiting on the network of FIG. 1; FIG. 4 represents a protocol for exchanges between different elements of FIG. 2, with illustration of a quarantine phase implemented;

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- la figure 5 représente un protocole d'échanges entre différents éléments de la figure 2, sans phase de quarantaine ; - la figure 6 illustre un algorithme de génération de marqueurs effectuée par un microprocesseur du portail illustré en regard de la figure 2 ; la figure 7 illustre un algorithme de comptage de réinitialisation de bus effectuée par un microprocesseur du portail illustré en regard de la figure 2 ; - la figure 8 décrit un algorithme de contrôle d'ATF mis en oeuvre lors de la détection d'une réinitialisation de bus par le portail de la figure 2.

FIG. 5 represents a protocol of exchanges between different elements of FIG. 2, without quarantine phase; FIG. 6 illustrates a marker generation algorithm performed by a gate microprocessor illustrated with reference to FIG. 2; FIG. 7 illustrates a bus reset counting algorithm performed by a portal microprocessor illustrated with reference to FIG. 2; FIG. 8 describes an ATF control algorithm implemented during the detection of a bus reset by the gate of FIG. 2.

 The invention has applications in many fields, and is particularly applicable in the context of: high-speed switching; distributed applications; transmission and / or reception of digital data; audio applications; business networks; and the transmission of images in real time.

 A preferred field of application of the invention is that of domestic applications for high-speed transfers. An exemplary system embodying the invention is described below, used to interconnect a plurality of audio and video devices in the home.

 A communication node is used to relay data packets between different elements of a network. Typically, the communication node receives data packets to be transmitted, prepares them for transmission and transmits them. Thus, it generally comprises: a buffer zone for storing the packets to be transmitted before the preparation; a module for preparing the packets to be transmitted (for example DMA controller); and

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 a packet transmission module (for example, a transmission FIFO type memory) on the physical layer.

 After a modification of the operating conditions of the network (for example change of topology of the network), the addressing and / or routing information contained in the packets are no longer valid. This information must be updated.

 When the packets are being prepared for transmission by the link layer, it is difficult to modify the content and thus update the addressing and / or routing information.

 During a modification of the operating conditions of the network, a modification signal is sent on the network.

 The general principle of the invention is based on the insertion on the fly by a communication node, of a marker (for example of a particular packet type) in a stream of packets sent to packet transmission modules, as soon as a change of mode of the network or part of the network is detected.

 Taking into account the packets by the modules responsible for the transmission on the physical layer being done sequentially and the detection information being inserted into the packet stream, after a modification of the operating conditions of the network, all the packets are found in the stream after the occurrence of the modification signal and before the marker relating to that signal and only these packets may contain obsolete addressing and / or routing data; thus, these packets require special processing that can be performed by the transmission modules during the particular processing period.

 The communication node (and more particularly, the packet transmission module) then changes from a normal transmission mode (which is the default mode) to a separate processing mode. This mode is easily detected by the packet transmission module. Indeed, a distinct mode of treatment is delimited by the occurrence of a network operating mode change signal and the taking into account of the marker

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 corresponding (for the sake of clarity, it is assumed here that there is no change in network operating mode during the separate processing mode).

 Thus, the packet transmission module performs particular packet processing whose preparation has started and which are placed in the stream of packets to be transmitted have not been transmitted before the occurrence of the mode change.

These particular processes are for example of transmission type of the packets on the physical layer or put away (purge). According to the invention, their nature depends on the mode (default mode or separate processing mode) of the communication node.

Several different processing modes are possible: in some cases, only certain packets can not be transmitted on the physical layer (in case some packet fields are obsolete or if a quarantine period prohibits the transfer of or to remote buses); - in other cases, no packet can be transmitted.

 Thus, the different processing modes can take into account these aspects and in particular allow total purges of the packets ready to be transmitted on the physical layer or purges more targeted.

 Basic packet erase or transmission operations are part of the usual tasks of the modules in charge of the transmission. According to the invention, their management is based on the exploitation of the aforementioned distinct processing modes, in particular by electronic means that are simple to implement, software-driven and adapted to high data rates.

 In addition, according to the invention, a control means (which may be especially software and which is preferably in charge of the insertion of the packets and the marker in the stream of packets to be transmitted) may in particular: - modify the obsolete fields of packets present in the buffer zone to insert these updated packets as quickly as possible into the packet stream; and or

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 - postpone the insertion of unauthorized packets for immediate transmission to promote the transmission of other packets.

 A particular embodiment will now be exposed.

 Figure 1 illustrates an interconnected IEEE 1394 bus network 1, 2,3, 4 and 5.

 The IEEE 1394 buses are notably standardized according to the aforementioned documents P1394.1, IEEE Std 1394-1995 and IEEE Std 1394a-2000.

 Buses 1,2, 3,4 and 5 are interconnected by bridges 6,7, 8 and 9 as standardized in document P1394. 1 Draft Standard for high performance serial bus bridges cited above. The bridges 6, 7, 8 and 9 comprise at least two communication interfaces 10 and 11, 12 and 13, 14 and 15, 16 and 17, respectively. The bridges 6, 7, 8 and 9 can generate packets and enable communication between two adjacent buses. Thus, the bridge 9 allows communication between the buses 4 and 5.

 The communication interface on the bus is called portal (or in English, according to IEEE 1394 standards). Each portal can take into account all the signals transiting on the bus to which it is connected and all or part of the packets transmitted on this bus. Bridges 6,7, 8 and 9 include an element that allows data transfer and control between these two portals.

 Bridge portals must process data packets transferred across the network based on the identification of their destination and / or source. Thus, communication through an intermediate bus to a remote bus requires different processing of the communication on an initial bus or termination.

 All packets on an IEEE 1394 bus contain an address (or identifier) of a source node (packet sender) and a destination node.

 When a packet originates (respectively destination) a node on a local bus, its source identifier (respectively destination) corresponds to

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 a physical address that is not persistent during a bus reset on the network.

 In contrast, when a packet originates (respectively destination) a node on a remote bus, its source identifier (respectively destination) corresponds to a virtual address that is persistently maintained during a bus reset on the network.

- un composant 44 d'interface couche physique étroite IEEE 1394 pour la transmission sur le bus série IEEE 1394 2. Figure 2 illustrates the part of a portal relating to the invention. It describes the transmission means on a bridge gate 10 as illustrated with reference to FIG. 1. The gates 11 to 17 are quite similar to the gate 10 and will not be further described.
The portal 10 comprises in particular: a processor 50; a non-volatile memory (ROM) 52; a volatile memory (RAM) 51; a DMA (Direct Memory Access or Direct Memory Access) controller 41; an IEEE 1394 link layer 42 comprising an ATF memory (Asynchronous Transmit FIFO or FIFO of asynchronous transmission) 43; a bus 53 internal to the gate for the communication of data and control signals between these modules;

an IEEE 1394 narrow physical layer interface component 44 for transmission on the IEEE 1394 serial bus 2.

 The data transmission is under the control of a software control module 40 executed on the processor 50.

 The data is transferred to the IEEE 1394 link layer 42 from a RAM 51 memory location to the ATF 43 by the DMA controller 41 which can process a list of pending DMA transfers. The method for transferring data according to a DMA well known to those skilled in the art of

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 telecommunications is not the subject of this invention and will not be more detailed.

The ATF 43 can store several packets before a transmission on the bus 2 is allowed, that is to say before the PHY layer 44 gains an arbitration phase on the bus. The IEEE 1394 physical layer can detect and relay to the ATF 43 and the processor 50 any signal on the IEEE 1394 bus 2 in particular the reset bus signals (reset).

Note that when the transfer of a DMA addressed to the ATF 43 has been requested by the software control module 40, no control is possible on the data packets without the addition of a substantial hardware control logic which is costly in terms of resource and / or without emptying all packets in transit.

 Figure 3 describes the format of an IEEE 1394 asynchronous primary packet, as defined in the IEEE 1394 standards cited above.

 The package comprises two parts: - a header 20; and - a useful data part 21.

 For reasons of readability, the CRC (Cyclic Redundancy Check) and the CRC data that are added by the IEEE 1394 link layer before transmission on the IEEE 1394 bus are not mentioned in Figure 3. Thus, only the fields useful in the context of the present invention are highlighted.

 The header 20 comprises in particular: a destination identification field or Destination Id 22; a source identifier field Source Id 23; and a transaction code field tcode 24.

 The destination identification field or Destination Id 22 represents the destination address of the packet (physical or virtual address according to the cases as mentioned previously).

 He understands :

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 a 10-bit BusID field (or bits) that define the bus identifier (according to the IEEE 1394 standard, this identifier is equal to Ox3FF for a transmission on the local bus and any other value, which is unique , for transmission on a remote bus); and a 6-bit Node Id field which defines the node identifier.

 The Node ID node identifier field has a physical value when the packet is transferred to a local bus, and a virtual value when transferred from a remote bus.

 The physical identifier is not retained during a bus initialization (reset) while the virtual identifier is.

 The source identifier field Source Id 23 represents the initiator of an asynchronous packet. It comprises: a 10 bit field which defines the bus identifier (0x3FF) for a transmission from the local bus and any other value (but unique for each bus of a network) for a transmission from a remote bus; and a 6-bit field that defines the node identifier. This node identifier field has a physical value when the packet is transferred from a local bus, and a virtual value when transferred from a remote bus.

 The transaction code field tcode 24 notifies the type of the transaction.

The IEEE 1394 bus standards mentioned above specify the set of values to be used for the transaction code field. Some of them are not specified by standards and are reserved for future needs.

 FIG. 4 represents an exchange protocol between the RAM 51, the DMA controller 41, the ATF 43 and the bus 2 as illustrated with reference to FIG. 2, with a quarantine phase implemented. These different elements are

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 represented in FIG. 4 by vertical lines. The different operations between these elements are represented by arrows.

 It is noted that a first packet of data Pl (Idsl, Iddl) (the notation Pn (Idsx, Iddy) signifying a packet Pn having a source address Idsx in its field 23 and an destination address Iddy in its field 22) is transmitted to the RAM 51 during an operation 101, then to the controller 41 during an operation 105, then to the ATF during an operation 109 and finally on the bus 2 during an operation 102. These transmissions occurring in the absence of a bus reset, there is no modification of the source and destination addresses, nor of transfer interruption.

d'un paquet P3 ? (7 < 3, 7J37) par la RAM 51 et sa transmission 108 vers le contrôleur 41, un signal d'initialisation du bus est reçu par le microprocesseur 50, l'ATF 43 et le bus 2 lors d'une opération 104. Following receipt 102 of a packet P2 (Ids2, Idd2) by the RAM 51, then its transmissions 106 and 110 to the controller 41 and the ATF 43, to the generation of a packet P4 (Ids41, Idd4) by the gate 10, its transmission 107 of the RAM 51 to the controller 41 and its transmission 111 to the ATF 43, the reception 103

a P3 package? (7 <3, 7J37) by the RAM 51 and its transmission 108 to the controller 41, a bus initialization signal is received by the microprocessor 50, the ATF 43 and the bus 2 during an operation 104.

By way of example, the following packet characteristics are assumed: the packet P2 has remote source Ids2 and destination Idd2 addresses; the packet P3 has a remote Ids3 source address and a local destination address Odd31; and the P4 packet has a remote Ids41 source address and a local Idd4 destination address.

 The detection of the bus initialization signal has several immediate consequences, in particular: a period of quarantine starts (some so-called bridge aware devices implements a NETGENERATION register defined by the standard pl394.1 mentioned above so that they can manage their period quarantine thanks to a bit of the register noted q set to 1 (this

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- un paquet de type marqueur est généré par le processeur 50 et transmis de la RAM 51 vers le contrôleur 41 au cours d'une opération 113 ; puis un paquet P5 (Ids5, Idd5) (avec adresse destination Idd5 locale) est généré par le processeur 50 et transmis de la RAM 51 vers le contrôleur 41 au cours d'une opération 114 (la génération du paquet P5 est donné ici à simple titre illustratif, car relativement fréquente mais non obligatoire à la suite d'une réinitialisation de bus) ; puis - l'adresse destination Idd31 étant locale du paquet P3, c'est une adresse physique. Elle est donc devenue obsolète après la réinitialisation du bus. Le microprocesseur 50 la met à jour dans le paquet P3 stocké en mémoire RAM 51. Le paquet P3 (Ids3, Idd32) est alors transmis au contrôleur 41 au cours d'une opération 115. which indicates that a change in severe topology has taken place); the quarantine period ends when the coordinating node of the local bus performs a write operation in the register
NET-GENERATION of all the components attached to the bus, which has the effect of resetting the bit q);

a marker type packet is generated by the processor 50 and transmitted from the RAM 51 to the controller 41 during an operation 113; then a packet P5 (Ids5, Idd5) (with destination address Idd5 local) is generated by the processor 50 and transmitted from the RAM 51 to the controller 41 during an operation 114 (the generation of the packet P5 is given here as a simple illustrative title, because relatively frequent but not mandatory after a bus reset); then - the destination address Idd31 being local of the packet P3, it is a physical address. It has become obsolete after the bus has been reset. The microprocessor 50 updates it in the packet P3 stored in RAM 51. The packet P3 (Ids3, Idd32) is then transmitted to the controller 41 during an operation 115.

 The DMA controller 41 continues to normally process the packets it receives by transmitting them to the ATF 43 in their chronological order of reception. Thus, the packet P3 (lds3, Idd31), the marker and then the packets P5 (lds5, Idd5) and P3 (Ids3, odd32) are transmitted to the ATF 43 during the operations 116, 117, 118 and 120.

- ne pas émettre des paquets comportant une adresse de destination distantes pendant la période de quarantaine 119 ; et - ne pas émettre de paquets comportant au moins une adresse locale, celle-ci étant devenue obsolète. Resetting the bus also has consequences for the ATF, which will discard the packets that reach it before the marker for:

- Do not send packets with a remote destination address during the quarantine period 119; and - not to send packets containing at least one local address, this one having become obsolete.

 Thus, the tcode code 24 of each packet present in the ATF will be analyzed according to its chronological order of arrival to determine if it possesses

<Desc / Clms Page number 21>

l'ATF efface le marqueur au cours d'une opération 124. a value corresponding to that of a marker. As an illustration, it is assumed here that there is no new bus reset. Thus, as long as a marker-type packet is not detected, the ATF clears the packets. This is why the packets P2, P4 and P3 (Ids3, Odd31) are discarded during operations 121 to 123. Then,

the ATF clears the marker during an operation 124.

 Then (that is after detection of the marker), the ATF can transmit without analysis of their contents the packets that it receives. Thus, the packets P5 and P3 (Ids3, Idd32) are transmitted on the bus 2 during the operations 125 and 126.

 After the quarantine period 119, the packets destined for remote nodes can be transmitted again on the bus 2.

l'ATF 43 et au bus 2 au cours des opérations 127 à 132. Also, the packets P2 (Ids2, Idd2) and P4 (Ids42, Idd4) (the microprocessor 50 has previously replaced the source address of P4, Ids41, local by an updated address Ids42) are transmitted from the RAM 51, to the DMA controller 41 then to

ATF 43 and bus 2 during operations 127 to 132.

FIG. 5 represents a protocol for exchanges between the RAM 51, the DMA controller 41, the ATF 43 and the bus 2 as illustrated with reference to FIG. 2, without quarantine phase implemented. These different elements are represented in the figure by vertical lines. The different operations between these elements are represented by arrows.

 The transmitted packets are similar to those mentioned in Figure 4.

 Likewise, the operations until the bus is reset are identical to those in FIG. 4. They are therefore not recalled here.

 Here, it is assumed that there is no quarantine period (the q bits of the NETGENERATION register are not all set to 1).

 Under these conditions, the detection of the bus initialization signal does not have quite the same consequences as those related to the presence of a quarantine period. In particular, packets that have remote source and destination addresses can be transmitted without modification. Only an update of the local addresses is necessary in the concerned packets.

<Desc / Clms Page number 22>

Also, the following operations are repeated: - generation of marker 113 and transmission to the controller 41, then - generation 114 and transmission of the packet P5 (Ids5, Idd5) of the RAM 51 to the controller 41.

 Nevertheless, here, it is no longer necessary to defer the transmission of the packet P4. Also, the processor 50 updates the local source address and the packet P4 (Ids42, Idd4) is transmitted to the controller 41 during an operation 142.

 Then, the processor 50 updates the local destination address of the packet P3 and the packet P3 (Ids3, Idd32) is transmitted to the controller 41 during an operation 115.

reçoit en les transmettant à l'ATF 43 suivant leur ordre chronologique de réception. Ainsi, le paquet P3 (Ids3, Odd31), le marqueur puis les paquets P5 (Ids5, Idd5), P4 (Ids42, Idd4) et P3 (Ids3, Idd32) sont transmis à l'ATF 43 au cours des opérations 116,117, 118, 130 et 120. The DMA controller 41 continues to process normally the packets it

receives by transmitting them to the ATF 43 according to their chronological order of reception. Thus, the packet P3 (Ids3, Odd31), the marker and then the packets P5 (Ids5, Idd5), P4 (Ids42, Idd4) and P3 (Ids3, Idd32) are transmitted to ATF 43 during operations 116, 117, 118. , 130 and 120.

 Resetting the bus also has consequences for the ATF 43 which will discard the packets that reach it before the marker for not sending packets containing at least one local address, it has become obsolete.

 On the other hand, the ATF 43 may send packets with two remote source and destination addresses since there is no quarantine period.

 Thus, the tcode 24 of each packet present in the ATF will be analyzed according to its chronological order of arrival to determine if it has a value corresponding to that of a marker. As an illustration, it is assumed here that there is no new bus reset.

- si les deux adresses source et destination du paquets sont distantes, le paquets est émis sur le bus 2 ; dans le cas contraire, le paquet est effacé. Thus, as long as a tag type packet is not detected, the ATF analyzes the local or remote character of the source and destination addresses of the packets:

if the two source and destination addresses of the packets are distant, the packets are transmitted on the bus 2; otherwise, the packet is erased.

<Desc / Clms Page number 23>

Therefore, the P2 packet (Ids2, Idd2) (Ids2 and Idd2 being remote node addresses) is transmitted on the bus 2 during an operation 133.

In addition, the P4 packets (Ids41, odd4) and P. ? (73, 737) (the addresses Ids41 and Odd31 being local) are discarded during operations 134 and 135. Then, the ATF erases the marker during an operation 136.

 Then (that is after detection of the marker), the ATF can transmit without analysis of their contents the packets that it receives. Thus, the packets P5, P4 (Ids42, Idd4) and P3 (Ids3, Idd32) are transmitted on bus 2 during operations 137, 138 and 141.

 FIG. 6 illustrates a marker generation algorithm performed by a microprocessor of the gate 10 illustrated with reference to FIG. 2.

 The processor 50 implements the marker generation algorithm which comprises a first initialization operation 82 which generates a marker-type packet, i.e. having a tcode field 24 having a particular value not used in the process. standard and known to ATF 43 and lacking a useful data field 21.

 Then, this marker is placed in RAM 51 and will be kept during the entire operating phase of the portal 10.

 Then, during an operation 80, the processor 50 waits then detects (for example, by a dedicated interrupt signal) a reset of the bus.

 Then, during an operation 81, the processor 50 requests the transmission of the marker-type packet from the RAM 51 to the DMA controller 41 and the ATF 43.

 Then, operation 80 is reiterated.

 FIG. 7 illustrates a bus reset counting algorithm implemented by the link layer 42 illustrated with reference to FIG. 2.

 A bus bus reset counter is incremented at each bus initialization (according to the counting algorithm described with reference to FIG. 7) and decremented at each marker-type packet detection (according to the control algorithm described next to FIG. Figure 8). It allows in particular

<Desc / Clms Page number 24>

 the ATF to know if it is inside or outside a purge period of packets.

 The bus reset count algorithm includes a first initialization operation 92 that initializes the count counter to zero.

 Then, during an operation 90, the link layer 42 waits then detects (for example by a dedicated signal) a reset of the bus.

 Then, during an operation 91, the link layer 42 increments the count counter by one.

 Then, operation 90 is reiterated.

 The implementation of the bus reset count algorithm is relatively simple and generally requires a high speed of operation, it is preferably in electronic form.

 FIG. 8 describes an ATF control algorithm 43 to be applied during the detection of a bus reset, and implemented by the link layer 42 of the gate 10.

 Since the implementation of the control algorithm of ATF 43 is relatively simple and generally requires a high speed of operation, it is preferably in electronic form.

 After an initialization step, during a step 60 of detecting a bus reset signal, the ATF controller 43 waits then detects that the counter counter value is strictly positive. This indicates that ATF 43 is entering a packet purge phase.

sera indiqué au contrôleur de logiciel. It is recalled that during this purge phase, if the packet at the output of the ATF 43 is to or from a local bus, it will be discarded and the next packet can be processed. A dedicated erase or transmission signal

will be indicated to the software controller.

Then, during a step 61, the ATF 43 waits then takes into account a packet at its output.

<Desc / Clms Page number 25>

 Then, during a test 62, the link layer 42 analyzes the tcode field 24 of the packet and determines whether this field 24 has a value equal to the predefined hexadecimal value OxD corresponding to a marker.

 If so, the packet is a marker-type packet and, during an operation 143, the count counter is decremented by one, the packet is cleared and a clear-out signal is transmitted to the processor 50.

 Then, during a test 144, the link layer determines whether the count counter is zero.

 If not, operation 61 is repeated.

 If so, transaction 60 is repeated.

 If the result of the test 62 is negative, the packet is not a marker-type packet and, in a step 63, the link layer 42 determines whether the destination address indicated in the field 22 corresponds to a local address. . In other words, the link layer 42 tests whether the 10-bit field relative to the destination bus in the field 22 has a hexadecimal value equal to 0x3FF.

opération 70, l'ATF 42 efface le paquet et un signal indiquant un effacement est émis vers le processeur 50. If yes, the package is destined for the local bus during a

operation 70, the ATF 42 clears the packet and a signal indicating an erasure is transmitted to the processor 50.

 If not, the packet is destined for the remote bus and during a test 65, the link layer 42 determines whether the source address indicated in the field 22 corresponds to a local address. In other words, the link layer 42 tests whether the 10-bit field relative to the source bus in the field 23 has a hexadecimal value equal to Ox3FF.

 If so, the packet comes from the local bus and during an operation 70, the ATF 42 clears the packet and an erase signal is sent to the processor 50.

 If not, during a test 66, the ATF control 43 determines whether the local bus is in a quarantine period. In other words, the ATF control 43 tests whether the bit q of the NETGENERATION register is 1.

<Desc / Clms Page number 26>

Dans la négative, au cours d'une opération 67, l'ATF 42 émet sur le bus 2 le paquet et un signal indiquant la transmission et son statut (code d'acquittement provenant d'une réception sur un bus local ou code d'erreur de transmission) est émis vers le processeur 50. If so, during an operation 68, the ATF 42 clears the packet and an erase signal is sent to the processor 50.

In the negative, during an operation 67, the ATF 42 transmits on the bus 2 the packet and a signal indicating the transmission and its status (acknowledgment code from a reception on a local bus or code of transmission error) is transmitted to the processor 50.

 According to one variant, the tests 63 and 65 are grouped in a single operation.

 According to another variant, the tests are not performed in the same order.

 In general, during the purge phase, only packets to and from a remote bus can be transmitted and during the quarantine phase, packets destined for a remote bus can not be transmitted.

attente (incluant ceux qui étaient écartés par l'ATF 43) dans la file d'attente DMA 37 durant le traitement de réinitialisation de bus. Le contrôle logiciel 40 peut mettre dans la file d'attente DMA 37 tous les paquets asynchrones adressés au bus local durant la période de quarantaine sans bloquer l'ATF. Regardless of the processing mode of the ATF controller 43, the software control 40 still requires direct access to the DMA memory for all the asynchronous packets. The packets are processed sequentially and thus the software controller can always advance in its processing even if the ATF controller 43 has not finished purging the transit packets 31 to 35. This allows the software controller 40 to initialize sub-packets. asynchronous actions during the quarantine period (for example, to obtain the uniquely defined addresses commonly denoted EUI64, nodes connected on the local bus for filling a virtual identifier / physical identifier mapping table) and if no period quarantine (ie when the bit q of the NET-GENERATION register is set to zero). The software control 40 can then start putting packets that were in

waiting (including those discarded by ATF 43) in the DMA queue 37 during bus reset processing. The software control 40 can put in the DMA queue 37 all the asynchronous packets addressed to the local bus during the quarantine period without blocking the ATF.

<Desc / Clms Page number 27>

 Of course, the invention is not limited to the embodiments mentioned above.

 In particular, the skilled person may provide any variant in the definition of the architecture of the network which may include in particular several interfaces of the type of communication links for example of the IEEE1394 type.

la transmission de données numériques ; la réception de données numériques ; les applications audio ; les réseaux d'entreprise ; et la transmission d'images en temps réel. It is also noted that the invention applies to the following areas: high-speed switching; distributed applications;

digital data transmission; receiving digital data; audio applications; corporate networks; and the transmission of images in real time.

 In addition, it is noted that the communication node implementing the invention may comprise several FIFO-type transmission memories, some FIFOs being loaded for example with transmission over different links and / or transmission of different priorities. Each time the network mode of operation changes, a marker will then be inserted in each of the FIFOs which can then independently manage a packet processing mode.

 It will be noted that the invention is not limited to a purely material implantation but that it can also be implemented in the form of a sequence of instructions of a computer program or any form mixing a material part and a part software. In the case where the invention is partially or totally implemented in software form, the corresponding instruction sequence can be stored in a removable storage means (such as for example a floppy disk, a CD-ROM or a DVD-ROM) or no, this storage means being partially or completely readable by a computer or a microprocessor.

Claims (39)

1. A method of managing packets that can be processed according to at least a first transmission mode and at least one local processing mode, in a communication node (6) of a communication network, characterized in that said packets are inserted (105, 106, 107, 114) chronologically into at least one stream of packets and in that it comprises a step of inserting (113, 81) a marker in each said packet stream, when a change of mode is detected (114), so that, following the detection of said mode change (114), the packets (P2, P4, P3) remaining in said packet stream before said marker are processed according to one of said local processing modes. 2. Method according to claim 1, characterized in that said marker is a package of particular structure. 3. Method according to claim 2, characterized in that it comprises a purge step (124) of said marker so that it is not transmitted on said network. 4. Method according to any one of claims 1 to 3, characterized in that the packets and markers are: - inserted into said stream of packets by a control means (40,50); and - stored in a transmission means (42); said control means and said transmission means being adapted to implement said first transmission mode and at least one of said local processing modes. 5. Method according to claim 4, characterized in that it comprises a step of management (41) of a direct access to the memory allowing the transfer of the packets and markers inserted in said stream of packets of said control means to said means of transmission. <Desc / Clms Page number 29>  6. Method according to any one of claims 1 to 5, characterized in that a mode change corresponds to a change in operation of said network. 7. Method according to claim 6, characterized in that said mode change belongs to the group comprising: - resets (reset) of at least a portion of said network; the modifications of the topology of said network; and changes in packet routing conditions within said network. 8. Method according to any one of claims 1 to 7, characterized in that said mode change is detected by receiving a corresponding information signal (bus reset). 9. Method according to any one of claims 1 to 8, characterized in that said local processing modes belong to the group comprising: a total purge mode of all packets ready to transmit on said network; and a mixed mode in which packets ready to transmit on said network are purged or transmitted on said network according to a first determined rule. 10. Method according to claim 9, characterized in that a local processing mode is implemented (60,144) as the number (count) of the detected mode change is strictly greater than the number of markers purged by a transmission means. .  11. Method according to any one of claims 9 and 10, characterized in that said mixed mode is implemented when said network does not allow the transmission of certain packets according to said determined first rule. 12. Method according to any one of claims 9 to 11, characterized in that, during said mixed mode, a transmission means implements for each packet ready to transmit: a verification step (63,65,66) transmission authorization criteria; a step of transmission (67) of said packet on said network, if the result of said verification step is positive; and <Desc / Clms Page number 30>  a purge step (70, 69, 68) of said packet ready to transmit, if the result of said verification step is not positive 13. The method of claim 12, characterized in that said transmission authorization criteria are part of a group comprising: validity criteria of said packet; and - criteria for authorizing the transmission of the packet according to the state of the network and / or the characteristics of said packet. 14. Method according to any one of claims 12 to 13, characterized in that said step of verifying the transmission authorization criteria comprises taking into account the characteristics of the packet belonging to the group comprising: a source address (ID source) of the packet; a destination address (Destination ID) of the packet; an identifier (source ID, bus id) of network element in said source address of the packet; and - an identifier (ID Destination .id bus) of network element in said destination address of the packet. 15. Method according to any one of claims 12 to 14, characterized in that according to said transmission authorization criteria, the packets to and from a remote bus (1,4, 5) forming part of the network. are not allowed to be broadcast on the network (119 quarantine). 16. Method according to any one of claims 9 to 15, characterized in that, during said total purge mode and / or during said mixed mode, a control means reinserts said purged packets into said stream of packets. 17. The method of claim 16 characterized in that during said total purge mode and / or during said mixed mode, a control means updates (P3 (Ids3, Idd32), P4 (Ids42, Idd4)) at least one field inside the packets according to a determined second rule before inserting (P3, P4) again said purged packets into said packet stream. <Desc / Clms Page number 31>  18. Method according to claim 17, characterized in that according to this second predetermined rule, the fields are packet address fields from (P4 (Ids42, Idd4)) and / or destination (P3 (Ids3, Ide32 of local bus. 19. Method according to any one of claims 16 to 18, characterized in that said control means reinserts said purged packets (P3) only if immediate transmission of said packet is authorized on said network. 20. Method according to claim 19, characterized in that the control means implements: a verification of each packet to be transmitted; a new insertion of said packet in said packet stream if the verification indicates an immediate authorization to be transmitted; placing said packet in a queue of packets set aside if the verification does not indicate an immediate authorization to be transmitted; and a step of detecting a change of authorization mode to be transmitted and inserting into said packet flow packets placed in said packet queue set aside. 21. Application of the method according to any one of claims 1 to 20, characterized in that said communication node (6) is connected to at least one IEEE1394 bus. 22. Device for managing packets that can be processed according to at least a first transmission mode and at least one local processing mode, in a communication node (6) of a communication network, characterized in that said packets are inserted (105, 106, 107, 114) chronologically into at least one stream of packets and in that said device

 comprises means for inserting (113, 81) a marker in each said packet stream, when a mode change is detected (114), <Desc / Clms Page number 32>  so that, following the detection of said mode change, the packets (P2, P4, P3) remaining in said packet stream before said marker are processed according to one of said local processing modes. 23. Device according to claim 22, characterized in that it comprises means for purging said marker so that it is not transmitted on said network. 24. Device according to any one of claims 22 and 23, characterized in that it comprises: at least one control means adapted to insert in said packet stream said packets and said marker; and - at least one transmission means capable of storing said packets and said marker; said control means and said transmission means being adapted to implement said first transmission mode and at least one of said local processing modes. 25. Device according to any one of claims 22 to 24, characterized in that it comprises means for managing a direct access to the memory for the transfer of packets and markers inserted in said stream of packets of said means of control towards said transmission means. 26. Device according to any one of claims 22 to 25, characterized in that said mode change belongs to the group comprising: resets of at least a portion of said network; - modifications of the network topology; and

 changes in packet routing conditions within the network. 27. Device according to any one of claims 22 to 26, characterized in that it comprises means for receiving an information signal (reset bus) for detecting said change of mode. 28. Device according to any one of claims 22 to 27, characterized in that said local processing modes belong to the group comprising: a total purge mode of all packets ready to transmit on said network; and <Desc / Clms Page number 33>  a mixed mode in which the packets ready to transmit on said network are purged or transmitted on said network according to a first determined rule. 29. Device according to claim 28, characterized in that a local processing mode is implemented as the number of detected mode change is strictly greater than the number of markers purged by a transmission means. 30. Device according to any one of claims 28 and 29, characterized in that said mixed mode is implemented when said network does not allow the transmission of certain packets according to said determined first rule. 31. Device according to any one of claims 28 to 30, characterized in that it comprises a transmission means implementing, during said mixed mode, for each packet ready to transmit: a step of verification of authorization criteria transmission; a step of transmitting said packet on said network, if the result of said verification step is positive; and a purge step of said packet ready to transmit, if the result of said verification step is not positive 32. Device according to any one of claims 28 to 31, characterized in that it comprises a control means inserting again said purged packets in said stream of packets, during said total purge mode and / or during said mixed mode . 33. Device according to claim 32, characterized in that it comprises a control means updating at least one field inside the packets according to a second determined rule before inserting again said purged packets into said stream of packets during said total purge mode and / or during said mixed mode. 34. Device according to any one of claims 32 to 33, characterized in that said control means reinserts said purged packets only if immediate transmission of said packet is authorized on said network. <Desc / Clms Page number 34>  35. Module (ATF 43) for filtering packets that can be processed according to at least a first transmission mode and at least one local processing mode, in a communication node of a communication network, characterized in that said module comprises: a means for receiving said packets inserted chronologically in at least one packet stream; and

 means for detecting a marker inserted in each said packet stream, when a mode change is detected, so that, following the detection of said mode change, the packets remaining in said stream of packets before said marker are treated according to one of said local processing modes. 36. IEEE1394 communication node, characterized in that it comprises a device according to any one of claims 22 to 34 and / or a module according to claim 35. 37. Bridge for communication network characterized in that it comprises a device according to any one of claims 22 to 34 and / or a module according to claim 35 and in that it connects at least two elements of said network. A computer program comprising program code instructions for executing the steps of the packet management method according to any one of claims 1 to 21 when said program is run on a computer. A computer program product comprising program code instructions recorded on a medium usable in a computer, comprising computer readable programming means for performing a marker insertion step in at least one packet stream when a mode change is detected, packets being able to be processed according to at least a first transmission mode and at least one local processing mode, in a communication node of a communication network and inserted chronologically in at least one one of said packet streams, <Desc / Clms Page number 35>  so that, following the detection of said mode change, the packets remaining in said stream of packets before said marker are processed according to one of said local processing modes.