EP3942772A1

EP3942772A1 - Method for securing the transmission of at least one data packet along a data path of a telecommunications network, corresponding computer program product and device

Info

Publication number: EP3942772A1
Application number: EP20726188.4A
Authority: EP
Inventors: Emile Stephan; Gaël FROMENTOUX; Frédéric FIEAU
Original assignee: Orange SA
Current assignee: Orange SA
Priority date: 2019-03-22
Filing date: 2020-03-13
Publication date: 2022-01-26
Also published as: US20220159037A1; WO2020193902A1; FR3094163A1

Abstract

The invention concerns a method for securing the transmission of at least one data packet along a data path of a telecommunications network. According to such a method, a security device performs the following steps: obtaining (E200) a variance delay representative of a difference between an actual end-to-end transit delay of the at least one data packet along the data path and an expected end-to-end transit delay of the at least one data packet along the data path; and securing (E210) the transmission by implementing at least one security action based on the variance delay.

Description

DESCRIPTION

TITLE: Method for securing the transmission of at least one data packet along a data path of a telecommunications network, corresponding computer program product and device.

Field of the invention

The field of the invention is that of the implementation of telecommunications networks. The invention relates more particularly to securing the transmission of data in such telecommunications networks.

The invention has many applications, in particular, but not exclusively, in the field of telecommunications networks of last generations or of future generations.

Prior art and its drawbacks

There are methods making it possible to verify the passage of data packets through a succession of nodes of a data path of a telecommunications network. More particularly, these methods are suitable for verifying passage through so-called trusted nodes, that is to say known to the entity in charge of verifying the entities of the network. Examples include the PoT protocol (for "Proof of Transit" in English) developed by Cisco ^® and standardized within the IETF (for "Internet Engineering Task Force" in English).

However, such methods are most of the time said to be “administered” in the sense that they assume a pre-configuration of the nodes of the path on which we want to practice the verification. In the case of the PoT protocol, this pre-configuration is complex and cumbersome: The calculation algorithm depends on the topology of the path. For example, the power of the polynomial used for verification depends on the number of nodes in the data path. In addition, the protection of the algorithm requires the dynamic determination of polynomials associating the end routers of the data path. Likewise, such methods do not support variations on the data path and therefore apply to networks whose topology is very well understood.

Moreover, such methods only make it possible to prove the passage of data packets through trusted nodes of a data path, but do not say anything about what happens between two of these trusted nodes.

There is thus a need for a technique making it possible to secure the transmission of data along a data path by making it possible to estimate whether a modification of topology could have occurred along the data path between two trusted nodes, eg if a third party device that is not one of the trusted devices has been added on the data path, or if part of the hardware functions implemented along of the path have been deported in a virtualized manner.

There is also a need for the technique in question to be simple to implement.

Disclosure of the invention

In one embodiment of the invention, a method is provided for securing the transmission of at least one data packet along a data path of a telecommunications network. According to such a method, a security device performs the following steps:

obtaining a wandering delay representative of a difference between an effective end-to-end transit delay of said at least one data packet along the data path and an expected end-to-end transit delay said at least one data packet along the data path; and

securing the transmission by implementing at least one securing action from the wandering time.

Thus, the invention proposes a new and inventive solution for securing the transmission of data in a telecommunications network.

More particularly, obtaining a wandering delay associated with a packet having followed a given data path makes it possible to determine whether the delay that it actually took to travel the path in question (ie the end transit delay - effective end along the data path, the path extending between any two nodes of the network) is different from the expected delay, for example taking into account the known constraints of the physical implementation of the data path, to travel the path in question (ie the expected end-to-end transit delay along the data path). If this is the case, it can be inferred that the path in question has been changed, for example when a third-party device which is not one of the trusted devices has been added to the data path, or if part of the hardware functions located along the path has been deported in a virtualized manner.

According to one embodiment, obtaining the wandering delay corresponds to a calculation of the wandering delay comprising obtaining the effective end-to-end transit delay by:

pre-measure end-to-end transit delay along the data path; or by preliminary measurement of a half value of the round trip transit delay along the data path.

For example, when the data packet (s) is formatted according to the QUIC protocol, the total round trip transit times and on the downstream and upstream segments are obtained by observing the change in the value of the “spinbit” according to this protocol. . In this way, the effective end-to-end transit delays relating to the observation point are easily obtained.

According to one embodiment, the data path passes through at least one node of the network. For each of the nodes, the calculation of the wandering delay comprises obtaining a node crossing delay for said at least one data packet. The expected end-to-end transit delay is a function of said at least one crossing delay.

According to one embodiment, the data path passes through at least two nodes of the network. For each pair of nodes among the at least two nodes, calculating the roaming delay includes obtaining a propagation delay of said at least one data packet along the data path between the nodes of the node pair. The expected end-to-end transit delay is a function of said at least one propagation delay. The propagation delay is a physical parameter that is generally available in the equipment or during link deployments.

Thus, the expected end-to-end transit delay is more precise because it also takes into account the delay on the interconnections between the nodes.

According to one embodiment, the wandering delay is calculated as a function of the effective end-to-end transit delay from which is subtracted said at least one crossing delay and / or said at least one propagation delay.

Thus, the calculation of the wandering time is simple and robust.

According to one embodiment, the data path extends between a first and a second network node of the network, the security device being housed in the second network node. Said at least one crossing delay is obtained from at least one parameter conveyed within said at least one data packet.

For example, in the case of several data packets of a connection of the QUIC protocol, the crossing delay aggregated locally then conveyed by the last RESET or GOAWAY type packet of the stream in question. Thus, the crossing delays are easily conveyed along the data path to the device calculating the wandering delay.

According to one embodiment, when the securing device is housed in the second network node, said at least one securing action belongs to the group comprising:

recording of the wandering time in said at least one data packet. So the delay wandering remains associated with the data packet (s) regardless of its destination, thereby allowing subsequent verification that it (or they) may have been altered along the data path;

registration of the wandering delay in association with the data path in a routing plan of an autonomous domain of the network to which the data path belongs. Thus an overall security of the network is obtained via a mapping of the wandering times of the data paths of the network;

destruction or duplication for analysis of said at least one data packet when the wandering time is greater than a predetermined threshold;

transmitting the roaming delay to at least one other device included in a node which is not located along the data path for implementation of another security action. Thus a specific securing action can be implemented by a dedicated device; and

a combination of all or part of the alternatives of the aforementioned group.

Thus, a very low wander network can be formed based on a selection only of the roads whose wander is less than a predetermined value.

According to one embodiment, the securing device is not located along the data path. The crossing delay is received from said at least one node via at least one other data packet distinct from said at least one data packet.

According to one embodiment, when the securing device is not located along the data path, the crossing delay is received in encrypted form, the securing device and said at least one node sharing the knowledge of minus an encryption information.

Thus, the transfer of the crossing delay from the node (s) to the securing device is secure. For example, the encryption information can use some shared parameters of the PoT protocol.

According to one embodiment, said at least one piece of encryption information is obtained by said at least one node via said at least data packet.

According to one embodiment, when the securing device is not located along the data path, said at least one securing action belongs to the group comprising:

registration of the wandering delay in association with the data path in a routing plan of an autonomous domain of the network to which the data path belongs. Thus an overall security of the network is obtained via a mapping of the wandering times of the data paths of the network; transmitting the roaming delay to at least one other device included in a node which is not located along the data path for implementation of another security action. Thus a specific securing action can be implemented by a dedicated device; and

a combination of all or part of the above-mentioned alternatives of the group.

According to one embodiment, obtaining the wandering delay corresponds to receiving, via another data packet distinct from said at least one data packet, of the wandering delay from another device located along the data path. . Said at least one securing action belongs to the group comprising:

a combination of all or part of the above-mentioned alternatives of the group.

According to one embodiment, the securing method is implemented successively for a plurality of data paths of the network.

The invention also relates to a computer program comprising program code instructions for implementing the method as described above, according to any one of its various embodiments, when it is executed on a computer.

In one embodiment of the invention, there is provided a device for securing the transmission of at least one data packet along a data path of a telecommunications network. Such a securing device comprises a reprogrammable computing machine or a dedicated computing machine configured to implement the steps of the securing method according to the invention (according to any one of the various aforementioned embodiments).

Thus, the characteristics and advantages of this device are the same as those of the corresponding steps of the securing method described above. Therefore, they are not detailed further.

In one embodiment of the invention, there is provided a node of a telecommunications network. Such a network node comprises at least one aforementioned security device (according to any one of the various aforementioned embodiments). List of Figures

Other aims, characteristics and advantages of the invention will emerge more clearly on reading the following description, given by way of simple illustrative example, and not limiting, in relation to the figures, among which:

[fig. 1] represents a data path of an autonomous domain of a telecommunications network along which the data transmission is secured by implementing a security method according to an embodiment of the invention;

[fig. 2] represents the steps of a method for securing the transmission of data along a data path according to one embodiment of the invention;

[fig. 3] represents an example of exchanges between entities of a telecommunications network implementing the method for securing the transmission of data according to one embodiment of the invention;

[fig. 4] represents an example of exchanges between entities of a telecommunications network implementing the method for securing the transmission of data according to another embodiment of the invention;

[fig. 5] represents an example of exchanges between entities of a telecommunications network implementing the method for securing the transmission of data according to yet another embodiment of the invention;

[fig. 6] shows an example of a device structure allowing the implementation of the steps of the method of [fig. 2] according to one embodiment of the invention.

Detailed description of embodiments of the invention

The general principle of the invention is based on obtaining a wandering delay of one (or more) data packets along a data path (eg which extends between two of the nodes of the network) . More particularly, the wandering delay is representative of a difference between: an effective end-to-end transit delay of the data packet along the data path (ie the delay that the packet actually took to travel the data path); and an expected end-to-end transit delay of the data packet along the data path (i.e. all or part of the known delay, eg associated with trusted nodes, that the packet is supposed to take to travel the data path ).

Such a metric is relevant in order to secure the transmission of data in the network and a securing action can be implemented on the basis of such a wandering delay. For example, a value of the wandering time greater than a predetermined threshold is representative of the fact that the data path taken by the data packet could have been modified, for example example when a third-party device which is not part of the trusted devices has been added to the data path, or if part of the hardware functions located along the path have been deported in a virtualized manner.

We now present, in relation to [fig. 1] a data path of an autonomous domain AS (for “Autonomous System” in English) of a telecommunications network along which the data transmission is secured by a securing method according to an embodiment of the invention .

More particularly, a user terminal UE (for “User Equipment” in English) sends a data packet to a server Serv via the data path passing through the five network nodes, NI to N5, which are here nodes. of confidence. For example, trust in the nodes NI to N5 is established by implementing the PoT mechanism.

A securing device 100 implements the securing method described further below in relation to the steps shown in [fig. 2] in order to secure the data path between the UE terminal and the server Serv.

More particularly, during a step E200, a wandering delay representative of a difference between an effective end-to-end transit delay of one (or more) data packets along the data path and a The expected end-to-end transit delay of the data packet (s) along the data path is obtained.

In the embodiment of [fig. 1], obtaining the wandering time corresponds to a calculation of the wandering time by the device 100.

To do this, the device 100 obtains a time limit for crossing all or part of the trusted nodes for the data packet (s), the end-to-end transit delay expected at the node in which the device is located. device 100 being a function of the crossing time (s) in question.

For example, the crossing delay is supplied by the corresponding trusted node (ie NI or N2 or N3 or N4 or N5) to the device 100 in order to determine the wandering delay. To do this, in the embodiment of [fig. 1], each trusted node adds its own crossing delay to the value of the crossing delays of the nodes previously traversed by the packet or flow along the data path. The cumulative crossing delay value thus obtained is conveyed in a predefined field of the packet or stream in question (eg in the last RESET or GOAWAY packet of a QUIC connection, or periodically in any packet of the stream, or again in a packet added to the stream such as an ICMP packet, etc.). This is a so-called “in-band” embodiment (ie the crossing delay is included in the data packet (s) in the form of a particular field). In other so-called “out-of-band” embodiments, the value of the crossing delay is exported to the securing device via one (or more) packet which is not a data packet passing through the data path. . For example, the value of the crossing delay is exported via a PSAMP (for “Packet SAMPling”) protocol in the case of a single packet, or IPFIX (for “Internet Protocol Flow Information Export” in English, eg netflow v9 for Cisco ^® and Juniper) for the case of a flow of packets.

Back to [fig. 1], Table 1 below gives examples of crossing times (taking into account, for example, processing times in the entities in question, switching, etc.) involved in the various entities represented in [fig. . 1] when known.

[Table 1]

Moreover, in order to calculate the wandering delay, the device 100 obtains the effective end-to-end delay (i.e. between the terminal and the server). For example, the effective end-to-end delay is obtained by device 100 via the half value of the round trip delay of the data path. The value of the round trip delay in question is obtained for example via the “spinbit” when the data packet is according to the QUIC protocol. In other embodiments, the effective end-to-end delay is obtained by measuring the transit delay along the data path beforehand.

Assuming that the effective end-to-end transit delay in the present case is equal to 200ms, the device 100 calculates the wander delay by subtracting the known crossing delays, here 15 and 10 ms from the transit delay of effective end-to-end. We then obtain 200 - 15 - 10 = 175ms.

Furthermore, assuming that the propagation delay between trusted nodes along the path is known, the wandering delay can be refined in some embodiments by taking into account the propagation delay in question in the calculation of the transit delay. end-to-end expected. Such a propagation delay is obtained for example by preliminary measurement. For example, assuming that the propagation delay is equal to 30 ms in the topology of [fig. 1], the wander delay can be refined by subtracting the 30ms in question from the previously calculated value, ie 175ms. In the end, we obtain a wandering time calculated as being equal to 175 - 30 = 145ms.

In other embodiments not shown in [fig. 1], the security device 100 is implemented not in the server Serv, but in one of the trusted nodes NI to N5. In this case, device 100 calculates the time to wander from its position along the data path.

Moreover, in other embodiments described below in connection with [fig. 3], [fig. 4] and [fig. 5], the securing device does not calculate the wandering time, but receives it from a third-party device which performed the calculation. In this case, the step E200 for obtaining the wandering time limit is reduced to a step for receiving the wandering time.

During a step E210, the data transmission is made secure by implementing one (or more) securing action from the wandering time obtained in step E200.

For example, in the embodiment of [fig. 1] in which the security device 100 calculates the wandering time on the basis of information (eg the crossing times) included in the data packet (s) (the aforementioned "in-band" case), the security action belongs to the group comprising:

recording of the wandering period in the data packet (s);

registration of the wandering delay in association with the data path in a routing plan of an autonomous domain AS of the network to which the data path belongs (eg using an EGP protocol (for "Exterior Gateway Protocol" in English) of the type BGP (for “Border Gateway Protocol” in English));

destruction or duplication for analysis (e.g. via the transmission of the duplicated packet to analysis equipment) of the data packet (s) when the wandering time is greater than a predetermined threshold;

transmission of the wandering delay to at least one other device included in a node which is not located along the data path for the implementation of another security action (eg to a collector implementing an IPFIX protocol (for “Internet Protocol Flow Information Export” in English)); and

a combination of all or part of the above-mentioned alternatives of the group

We now present, in relation to [fig. 3] an implementation of the securing method according to one embodiment of the invention.

In the embodiment of [fig. 3], the first and second autonomous domains AS1 and AS2 of the network each comprise a data path connecting a user terminal UE1 or UE2 to an ASBR1 or ASBR2 border router (for “Autonomous System Border Router”) via a trusted network node of the router type R_AS1 or R_AS2. Other autonomous domains, indexed j and k, are also present, of which only the edge routers ASBRj and ASBRk are represented in order to interface with the other autonomous domains of the network.

All or part of the edge routers ASBR1, ASBR2, ASBRj, ASBRk comprises a securing device 100 'according to an embodiment different from the embodiment described above in relation to [FIG. 1] More particularly, the securing device 100 'does not calculate the wandering time, but receives it from a third party device which has previously performed the calculation. For example the device 100 'included in the edge router ASBR1 receives (arrow 300_1) the wandering delay sent by the network node R_AS1 which, for its part, implements the method according to the embodiment described above in relation with [fig. 1] (e.g. the network node R_AS1 comprises a securing device 100 as described above). It is the same with the device 100 'included in the edge router ASBR2 which receives (arrow 300_2) the wandering delay sent by the network node R_AS2 which, for its part, implements the method according to the embodiment described. above in relation to [fig. 1]

In general, the edge routers ASBR1, ASBR2, ASBRj, ASBRk can receive the wandering times of the various data paths, for example when the securing method is implemented successively for a plurality of data paths of the network. Such reception is done for example via information according to an IGP protocol (for “Interior gateway protocol”). The edge routers ASBR1, ASBR2, ASBRj, ASBRk aggregate the wandering delays of the data paths for which they receive such wandering delays and insert them as metrics in an EGP protocol (eg according to the BGP protocol) intended for other autonomous domains (arrows 300_3). Such transmissions can for example take place in parallel with transmissions of “conventional” EGP information (arrows 300_4).

In this way, according to the embodiment of [fig. 3] in which the securing device 100 'receives the wandering delay, the securing action belongs to the group comprising: registration of the wandering delay in association with the data path in a routing plan of an autonomous domain the network to which the data path belongs;

transmission of the wandering delay to at least one other device included in a node which is not located along the data path for the implementation of another security action (eg a registration by a third device of the delay d 'wandering in association with the data path in a routing plan); and

a combination of all or part of the above-mentioned alternatives of the group. In other embodiments not illustrated, the edge routers ASBR1, ASBR2, ASBRj, ASBRk comprise the securing device 100 according to the embodiment of [FIG. 1] In this way, the calculation of the wandering time of the data path on which a given edge router is located is carried out in the edge router in question.

We now present, in relation to [fig. 4] an implementation of the securing method according to another embodiment of the invention.

More particularly, the embodiment shown in [fig. 4] uses the elements of the embodiment of [fig. 3] Only a road reflector RR1, RR_ASj, RR_ASk (for "Route Reflector" in English) is used in the corresponding autonomous domains.

In this way, the security device 100 ′ is for example here included in the route reflector RR1 so as to inject the wandering times of the data paths received from the edge router ASBR1 (arrow 400_1) as metrics in the EGP (eg according to the BGP protocol). According to the considered embodiment discussed above in relation to [fig. 3], the edge router ASBR1 itself calculated the wandering time associated with the data path on which it is located (eg the edge router ASBR1 includes a device 100 as illustrated in [fig. 4]) or received the wandering delay in question (calculated by a trusted node of the path in question which, for its part, comprises eg a device 100 in this case not illustrated in [fig. 4]) as well as possibly the wandering delays associated with the other paths of the autonomous domain considered.

Back to [fig. 4], the updated EGP is sent to the edge router ASBR1 (arrow 400_2) for forwarding to the other autonomous domains (arrows 300_3). Such transmissions can for example take place in parallel with transmissions of “conventional” EGP information (arrows 300_4).

Thus, according to the embodiment of [fig. 4] the securing securing action is of the same nature as in the embodiment described above in relation to [fig. 3]

We now present, in relation to [fig. 5] an implementation of the securing method according to yet another embodiment of the invention.

In the embodiment of [fig. 5], the security device 100 "calculates the wandering delay on the basis of information (eg the crossing delays) which are transmitted to it by a means other than via the data packet (s). In other words, the data packet (or packets) passing along the data path for which the wandering delay is to be obtained does not convey the crossing delays (“out-of-band” embodiment mentioned above). In fact, the security device 100 "is located here in a collector Coll of the IPFIX type. In other embodiments, device 100 "is located in a trusted node which is not located on the data path to be secured. More particularly, the securing device 100 "receives the crossing delay (s) from a corresponding trusted node NI, N2, N3, N5, N6 via one (or more) other data packet distinct from the (or des) data packet transiting on a data path for which the securing device 100 "will calculate the wandering time.

To do this, the controller configures (arrows 500_1) in addition the level of aggregation of the flow and the address of the collector Coll in each node NI, N2, N3, N5, N6. The Contr controller also configures the level of aggregation of the flow and the characteristics of the connection with the Coll collector (address, keys, etc.).

Then the data packets transport the two parameters "in-band" (i.e. in a data field which they themselves transport):

RND; and

PoT: partial sum of the shared secret that the nodes NI, N2, N3, N5, N6 calculate (the constant of the polynomial POLY1 according to PoT).

As recalled above, in the embodiment of [fig. 5], the securing device 100 "calculates the wandering delay on the basis of information (eg the crossing delays) which are not transmitted to it via the data packet (s) passing along the data path for which we want to calculate the wandering delay (the aforementioned “out-of-band” case). In this way, the nodes NI, N2, N3, N5, N6 do not insert their crossing delay in the data packets transiting on the data path in question, an NI, N2, N3, N5 or N6 cannot therefore calculate a wander delay.

In order to protect the exchanges, the Contr controller activates the PoT protocol on the NI path to N5 in NI, N2 and N5. More particularly, the Controller Contr configures (arrows 500_1) the common secret POLY2 and the secret of each node NI, N2, N5 of the path (xi, yi) at the level of each of the nodes in question, as well as of the expected result at the level of the last node of the path, here N5. N5 is therefore the only one (after the Contr controller) to know the expected PoT measurement (aka the constant of POLY1). Then each node protects its crossing delay value using at least one of the PoT parameters known or calculable by the controller Contr, for example POLY1, POLY2, RND and the secret of each node (xi, yi). For example. This allows :

The detection of the modification and authentication of the transit nodes in the nodes: (xi, yi) is used as HMAC signature key (for "keyed-hash message authentication code" in English),

Read protection: RND and used as an encryption key for example with AES (for "Advanced Encryption Standard" in English). The activation of PoT can be partial and limited to POLY1. Optionally, for a flow of packets of a connection according to the QUIC protocol going from the user terminal UE to the server Serv, each node NI, N2, N3, N5 or N6 synchronizes the export of the IPFIX ticket on the rising edges of the "spinbits" QUIC packets and adds the half effective round trip transit time measurements obtained in the ticket. This does two things:

each node NI, N2, N3, N5 or N6 exports (arrows 500_2) to the collector Coll a ticket describing the same sequence of data packets. This increases the precision of the comparison and the aggregation of the crossing times; and

the half effective round trip transit time obtained, in particular at node N5, allows a very precise calculation of the wandering delay.

An example of a ticket format is:

{

Flux identify quintupled, ...

to,

tl,

number of bytes,

number of packages,

cumulative local crossing time,

Spatial delay: {half effective round trip upward transit time, half effective round trip downward transit time}

}

The device 100 "of the collector Coll receives the crossing times from the various nodes NI, N2, N3, N5, N6. It decrypts them using the" decryption keys "received from the controller Contr during configuration as described above. (In other words, the device 100 "decrypts (or decrypts) the crossing times of the various nodes NI, N2, N3, N5, N6 on the basis of encryption information which has been obtained by the various nodes in question NI, N2, N3, N5, N6 via the data packet (s) passing along the data path considered. Such encryption information is used by the various nodes in question to encrypt (or encrypt) their delay respective crossing). The device 100 "groups together the crossing times received from the various nodes NI, N2, N3, N5, N6 by flow of data packets according to the aggregation flows also received from the controller Contr during configuration. The device 100" calculates a delay d 'wandering for the data path corresponding to the requested aggregation.

The device 100 "groups the results together in a wandering delay matrix. The entries in the matrix correspond to the level of aggregation of the chosen stream (host, network, system autonomous). The device 100 ″ allows access to the matrix using, for example, the ALTO protocol (for “Application-Layer Traffic Optimization”). The security device 100 ″ measures the variation in wandering time. It signals an excessive increase as a possible attack of a path node on the packet flow.

Alternatively, or in combination, the securing device 100 "transmits the wandering delay (s) to at least one other device included in a node which is not located along the data path for implementation of another securing action (eg an entry by a third party device of the wandering delay (s) in association with the data path in a routing plan).

Thus, according to the embodiment of [fig. 5] the securing action is of the same nature as in the embodiment described above in relation to [fig. 3] and [fig. 4]

For example, the securing device 100 ″ transmits the wandering delay (s) to a route reflector RR (eg the route reflector RR comprises a device 100 ′ as illustrated in [fig. 5]) so as to inject the wander delay (s) of the calculated or received data paths (arrow 500_3) as metrics in the EGP (eg according to the BGP protocol). The updated EGP is sent back by the route reflector RR to all or part of the nodes NI, N2, N3, N5, N6 (arrow 500_4).

In other embodiments, types of protection other than that implemented in the PoT protocol are used for the transmission of data (e.g. the crossing or link delay (s)) to the securing device.

In yet other embodiments, no data protection is implemented for the transmission of the data (e.g. the crossing or link delay (s)) to the securing device.

We now present, in relation to [fig. 6] an example of a device structure 600 making it possible to implement the steps of the securing method of [FIG. 2] according to one embodiment of the invention.

The device 600 comprises a random access memory 603 (for example a RAM memory), a processing unit 602 equipped for example with a processor, and controlled by a computer program stored in a read only memory 601 (for example a ROM memory or a hard disc). On initialization, the code instructions of the computer program are, for example, loaded into the random access memory 603 before being executed by the processor of the processing unit 602.

This [fig. 6] illustrates only one particular way, among several possible, of making the device 600 so that it performs certain steps of the securing method according to the invention (according to any one of the embodiments and / or variants described). s above in relation with [fig. 2]). In fact, these steps can be carried out either on a reprogrammable computing machine (a PC computer, a DSP processor or a microcontroller) executing a program comprising a sequence of instructions, or on a dedicated computing machine (for example a set of logic gates such as an FPGA or ASIC, or any other hardware module).

In the case where the device 600 is produced with a reprogrammable computing machine, the corresponding program (that is to say the sequence of instructions) can be stored in a removable storage medium (such as for example a floppy disk, CD-ROM or DVD-ROM) or not, this storage medium being partially or totally readable by a computer or a processor.

In some embodiments, device 600 implements any one of securing devices 100, 100 'or 100 ".

In some embodiments, the device 600 implements several or all of the securing devices 100, 100 'or 100 ".

In some embodiments, device 600 is included in a network node

(e.g. NI, N2, N3, N4, N5, N6, RR, Coll, AS B R, R_AS, etc.).

Claims

1. Method for securing the transmission of at least one data packet along a data path of a telecommunications network,

characterized in that a securing device (100, 100 ', 100 ", 600) performs the following steps:

obtaining (E200) a wandering delay representative of a difference between an effective end-to-end transit delay of said at least one data packet along said data path and an end-to-end transit delay expected end of said at least one data packet along said data path; and

securing (E210) of said transmission by implementing at least one securing action from said wandering time.

2. The method of claim 1 wherein said obtaining of said wandering delay corresponds to a calculation of said wandering delay comprising obtaining said effective end-to-end transit delay by:

previously measuring said end-to-end transit delay along said data path; or by

prior measurement of a half value of the round trip transit delay along said data path.

3. The method of claim 2 wherein said data path passes through at least one node of said network,

and wherein, for each of said nodes, said calculating said wandering delay comprises obtaining a crossing delay of said node for said at least one data packet,

said expected end-to-end transit delay being a function of said at least one crossing delay.

4. The method of claim 3 wherein said data path passes through at least two nodes of said network,

and wherein, for each pair of nodes among said at least two nodes, said calculating said wandering delay comprises obtaining a propagation delay of said at least one data packet along said data path between nodes of said pair of knots, said expected end-to-end transit delay being a function of said at least one propagation delay.

5. The method of claim 4 wherein said wandering delay is calculated as a function of said effective end-to-end transit delay from which is subtracted said at least one crossing delay and / or said at least one propagation delay. .

6. Method according to any one of claims 3 to 5 wherein said data path extends between a first and a second network node of said network, said security device (100, 600) being housed in said second network node. network,

wherein said at least one crossing delay is obtained from at least one parameter conveyed within said at least one data packet.

7. Method according to any one of claims 1 to 6 wherein said at least one securing action belongs to the group comprising:

recording said wandering delay in said at least one data packet;

registering said wander delay in association with said data path in a routing plan of an autonomous domain of said network to which said data path belongs;

destruction or duplication for analysis of said at least one data packet when said wandering time is greater than a predetermined threshold;

transmitting said wandering delay to at least one other device included in a node which is not located along said data path for implementation of another security action; and

a combination of all or part of the above-mentioned alternatives of the group.

8. Method according to any one of claims 3 to 5 wherein said security device (100 ", 600) is not located along said data path,

and wherein said crossing delay is received from said at least one node via at least one other data packet distinct from said at least one data packet.

9. The method of claim 8 wherein said crossing delay is received in encrypted form, said security device and said at least one node sharing knowledge of at least one encryption information.

10. A method according to any one of claims 1 to 5, or according to claim 8 or 9, wherein said at least one securing action belongs to the group comprising: recording said wandering delay in association with said data path in a routing plan of an autonomous domain of said network to which said data path belongs; transmitting said wandering delay to at least one other device included in a node which is not located along said data path for implementation of another security action; and

a combination of all or part of the above-mentioned alternatives of the group.

11. The method of claim 1 wherein said obtaining of said wandering delay corresponds to receipt, via another data packet distinct from said at least one data packet, of said wandering delay from another device located along said path. of data,

and wherein said at least one securing action belongs to the group comprising: recording said wandering delay in association with said data path in a routing plan of an autonomous domain of said network to which said data path belongs; transmitting said wandering delay to at least one other device included in a node which is not located along said data path for implementation of another security action; and

a combination of all or part of the above-mentioned alternatives of the group.

12. Computer program product comprising program code instructions for implementing the method according to any one of claims 1 to 11, when said program is executed on a computer.

13. Device (100, 100 ', 100 ", 600) for securing the transmission of at least one data packet along a data path of a telecommunications network,

characterized in that it comprises a reprogrammable computing machine (602) or a dedicated computing machine, configured for:

obtain a wandering delay representative of a difference between an effective end-to-end transit delay of said at least one data packet along said data path and an expected end-to-end transit delay from said to at least one data packet along said data path; and

secure said transmission by implementing at least one security action at from said wandering period.

14. Node (NI, N2, N3, N4, N5, N6, RR, Coll, ASBR, R_AS) of a telecommunications network characterized in that it comprises at least one device according to claim 13.