WO2009053636A2 - Method and device for processing data packets in a communication network supporting a plurality of levels of importance and of classes of service for the data packets - Google Patents

Abstract

The invention relates to a method of processing data packets in a communications network supporting a plurality of levels of importance and of classes of service. The method comprises the following steps; receiving data packets each having a chosen level of importance and a chosen class of service; providing a plurality of queues (Q1 to Q6) each dedicated to a chosen level of importance; each queue (Q) possessing a plurality of storage areas (Zij) each dedicated to a chosen class of service; storing the current data packet in the storage area (Zij) corresponding to the class of service of said data packet thus processed and belonging to the queue (Q) of corresponding level of importance; and for each data packet thus stored, applying a processing algorithm dependent on the level of importance and the class of service of said packet.

Description

 METHOD AND DEVICE FOR PROCESSING DATA PACKETS IN A COMMUNICATION NETWORK SUPPORTING A PLURALITY OF IMPORTANCE LEVELS AND SERVICE CLASSES FOR DATA PACKETS.

The present invention relates to the processing of data packets in a communications network supporting a plurality of importance levels and classes of service for the data packets. It finds a general application in communication services of the voice, video and / or application data type, and more particularly in Voice over IP type communications still called VoIP for "Voice over Internet Protocol".

Under VoIP, especially under the MPLS ("Multiple Protocol Label Switching") protocol, data packets representing voice, video, and / or application data are typically transmitted by routers that can introduce a processing delay or delete the data. because of congestion problems, or congestion of the network occurring, for example, in the case of specific events such as natural disasters, terrorist attacks or the like, to enable the routing of priority calls, despite such events, commercial routers process the VoIP data packets according to separate priority queues or queues in which the highest priority packets, for example clock clock data packets, may be treated first, while others can be treated later or deleted to decongest the network, for example, architecture is based on eight queues associated respectively with eight classes of service, one queue for each class of service.

In US-B-7006440, the classes of service may also be processed according to customer-related criteria so as to preferentially treat certain customers who have subscribed to a particular service to the detriment of customers who have not subscribed to it. Such a method thus makes it possible process data packets based on predefined customer discrimination.

Also known are differentiated services, also called "DiffServ" in which certain types of traffic such as voice have precedence over other types such as video or application data (ftp, http, ...). Thus, the data packets representing the voice are processed in priority over the data packets representing the video or the application data.

In document US-B-7050447, a so-called "priority" processing queue also has larger memory resources than the other non-priority queues for processing the data packets in a discriminatory manner according to a predefined priority scheme.

Such data packet processing of the prior art is not entirely satisfactory insofar as the discrimination of the packets is of relatively restrictive and fixed implementation since it is linked to the client (US-B-7006440), to the source or the nature of the packets (DiffServ), or requires an additional management algorithm of the memory resources of a priority queue (US7050447).

The present invention overcomes these disadvantages. It thus aims to further improve the processing of data packets in a communication network supporting a plurality of importance levels and classes of services of the packets and this independently of the source (port) of the data packets, the client, the memory space of the queues or the nature of the data packet (voice, video, applications).

It relates to a method of processing data packets in a communications network supporting a plurality of importance levels and classes of service for the data packets.

According to a general definition of the invention, the method comprises the following steps: receiving data packets each having a chosen importance level and a chosen class of service; providing a plurality of tails each dedicated to a selected level of importance; each queue having a plurality of storage areas each dedicated to a selected class of service;

storing the current data packet in the storage area corresponding to the service class of said data packet thus processed and belonging to the corresponding importance level queue; and

for each data packet thus stored, apply a processing algorithm according to the importance level and the service class of said packet.

Such processing of data packets according to several queues according to the importance level and the service class of the packets allows for a more flexible, richer, and more robust data packetization discrimination than the discriminations of the data packets. prior art.

Indeed, it is possible to define a "drop" algorithm for data packets, taking into account, first and foremost, the importance level of the packet and then the class of service to which the packet belongs. In practice, the communication network supports six levels of importance and eight classes of service for the data packets.

According to one embodiment, each data packet comprises a field dedicated to the importance level and a field dedicated to the service class of said packet. For example, in the IP protocol ("Internet Protocol"), the field dedicated to the importance level and the field dedicated to the class of service are contained in the TOS field.

As a variant, in the MPLS protocol, the field dedicated to the importance level is the Cos field and the field dedicated to the class of service is contained in the tag field.

The present invention also relates to a device for processing data packets in a communications network supporting a plurality of importance levels and classes of service for the data packets.

According to another aspect of the invention, the device comprises:

receiving means for receiving data packets each having a chosen importance level and a selected class of service; a plurality of tails each dedicated to a selected level of importance; each queue having a plurality of storage areas each dedicated to a selected class of service; storage means for storing the current data packet in the storage area corresponding to the service class of said data packet thus processed and belonging to the corresponding importance level queue; and

processing means able, for each data packet thus stored, to apply a processing algorithm depending on the importance level and the service class of said packet.

Other features of the invention will become apparent in the light of the detailed description below and the drawings in which: FIG. 1 schematically illustrates a plurality of tails able to discriminate the data packets according to the level of importance and the class of service of said packets according to the invention; and

FIG. 2 is a variant of implementation of the tails according to the invention.

The present invention finds application in a communication network supporting multiple levels of importance and several classes of service for data packets. In general, data routing uses a protocol that can be IP, MPLS or the like. For example, the six levels of importance are, in descending order of importance: override override flash, override flash, flash, immediate, priority, and routine.

The importance level can be established during the call by means of a specific button or a specific action performed from a menu displayed on the terminal, or during the establishment of the call, or physically attached to the terminal (most likely).

A call server ("Call server") is responsible for establishing the call and configures the importance level and the class of service. Call related information, including IP address, negotiated bandwidth, importance level, is loaded into the router for use as filtering and rating information.

Referring to Figure 1, a router comprises a plurality of PE input ports, individualized PE1 to PEN, and connected to data sources of different nature (voice, video, application data).

Each input port PE is connected to a processing chain including in particular a packet processor CL (individualized in CL1 to

CLN) of the "classifier" type adapted to detect a field in the header of the packet that identifies the importance level and the service class of said packet.

Each CL classifier sends packets to processors of "policer / shaper" POS type processing, individualized in POSij, with i the number of importance levels here 6, and j the number of service classes here. presence of 6 levels of importance and 8 classes of services per level, the router includes for each port of entry PE 48 processors of police type / shaper POS. It will be seen with reference to FIG. 2 that the number of relevant classes to be processed may be less than eight.

The router further comprises 6 priority tails Q, individualized in Q1 to Q6.

Tail Q1 is associated with importance level "Flash override override", tail Q2 is associated with importance level "Flash override ", the queue Q3 is associated with the importance level" Flash ", the queue Q4 is associated with the importance level" Immediate ", the queue Q5 is associated with the importance level" priority "and the queue Q6 is associated at the level of importance "routine". Each priority queue Q includes Z storage areas

(individualized in Zij), each associated with a class of service. Thus, the "override override flash" level of level includes 8 individual Z11 to Z18 storage areas, the Z11 zone being associated with the "NC" class of service, the Z12 zone being associated with the "H1" class of service Z13 being associated with the service class "EF express forwarding", the Z14 zone being associated with the service class "H2", the zone Z15 being associated with the service class "L1", the zone Z16 being associated with the service class "assured forwarding AF", the zone Z17 being associated with the service class "L2", and the zone Z18 being associated with the class "best effort service BE".

Each storage area Z comprises a buffer memory.

The current data packet is stored in the storage area Z corresponding to the service class of said data packet thus processed and belonging to the corresponding importance level queue. For example, the data packet having the importance level "flash" and service class "best effort" is stored in the storage area Z38.

Packets entering and leaving the tails are counted by elementary counters SH, individualized in SH1 to SH6, and each dedicated to a respective tail.

A general counter CG counts the incoming and outgoing packets of the six elementary counters.

A processing mechanism, called "scheduling" is adapted, for each data packet thus stored, to apply a processing algorithm according to the importance level and the service class of said packet. The result of the mechanism is applied to the PS output port of the router.

Thanks to this mechanism, it is therefore possible to process only the packets belonging to the highest level of importance and to the highest class of service and to drop ("drop") the other packets in the event of traffic congestion.

Referring to FIG. 2, an implementation variant has been described in which the priority queues only process 6 classes of services, instead of 8 as described with reference to FIG. storage associated with NC and H1 service classes that are treated separately, without passing through the priority queues Q1 to Q6.

Indeed, the NC and H 1 service classes are the highest priority classes. They only contain internal network control packets (protocols, ...) that are not the result of end-user communications. It is therefore not necessary to discriminate them by the tails Q1 to Q6.

In practice, each data packet includes a field dedicated to the importance level and a field dedicated to the service class of said packet.

In IP environment, the field dedicated to the importance level and the field dedicated to the class of service are contained in the TOS field.

In the MPLS environment, the field dedicated to the importance level is the Cos field and the field dedicated to the class of service is contained in the label field.

Claims

A method of processing data packets in a communications network supporting a plurality of importance levels and classes of service, wherein the method comprises the steps of: receiving data packets each having a selected level of importance and a chosen class of service;

providing a plurality of tails (Q1 to Q6) each dedicated to a chosen level of importance; each queue (Q) having a plurality of storage areas (Zij) each dedicated to a selected class of service;

storing the current data packet in the storage area (Zij) corresponding to the service class of said data packet thus processed and belonging to the queue (Q) of corresponding importance level; and for each data packet thus stored, applying a processing algorithm according to the importance level and the service class of said packet.

The method of claim 1 wherein the communication network supports six importance levels and eight service classes for the data packets.

The method of claim 1 wherein each data packet comprises a field dedicated to the importance level and a field dedicated to the service class of said packet.

4. The method of claim 3 wherein the field dedicated to the importance level and the field dedicated to the class of service are contained in the TOS field.

5. Method according to claim 3 wherein the field dedicated to the level of importance is the Cos field and the field dedicated to the class of service is contained in the label field.

A device for processing data packets in a communications network supporting a plurality of importance levels and classes of service, characterized in that it comprises:

receiving means (PE1 to PEN) for receiving data packets each having a chosen importance level and a selected class of service;

a plurality of tails (Q1 to Q6) each dedicated to a selected level of importance; each queue having a plurality of storage areas (Zij) each dedicated to a selected class of service;

storage means for storing the current data packet in the storage area corresponding to the service class of said data packet thus processed and belonging to the corresponding importance level queue; and

processing means able, for each data packet thus stored, to apply a processing algorithm depending on the importance level and the service class of said packet.