CN111181848B

CN111181848B - Network fragmentation method, system, router and storage medium

Info

Publication number: CN111181848B
Application number: CN201811328141.0A
Authority: CN
Inventors: 朱永庆; 陈华南; 龚霞; 黄灿灿; 伍佑明
Original assignee: China Telecom Corp Ltd
Current assignee: China Telecom Corp Ltd
Priority date: 2018-11-09
Filing date: 2018-11-09
Publication date: 2022-02-15
Anticipated expiration: 2038-11-09
Also published as: CN111181848A

Abstract

The invention discloses a network fragmentation method, a network fragmentation system, a router and a storage medium, and relates to the field of data communication. The network fragmentation method comprises the following steps: the router obtains a Segment Routing (SR) label corresponding to the router, wherein the SR label is allocated based on time slot information of a Flexe subinterface of the router on a path of the network fragments; the router sends the SR label of the router to other routers in the network; the router acquires SR labels sent by other routers in the network; and responding to the router as a head-end router, the router inserts a label forwarding stack into the message, wherein the label forwarding stack is generated based on the SR label on the path of the network fragment through which the message flows, so that other routers forward the message based on the label forwarding stack. The embodiment of the invention can bear the time slot information of the Flexe subinterface through the SR label. Therefore, the transmission of the time slot information of the Flexe subinterface is realized while the label forwarding based on the SR is realized, and the networking based on the Flexe is realized.

Description

Network fragmentation method, system, router and storage medium

Technical Field

The present invention relates to the field of data communications, and in particular, to a network fragmentation method, system, router, and storage medium.

Background

The FlexE (Flexible Ethernet) technology defines a mechanism for decoupling a MAC (Media Access Control) Layer from a PHY (Port Physical Layer), and supports MAC data streams with various Flexible rates. The Flexe fragments divide a physical Ethernet port into a plurality of Ethernet pipelines through time slot scheduling, and more choices are provided for 5G network fragments. FlexE is the future network fragmentation development direction.

However, the industry has no perfect FlexE bearing technology and mode, which limits the popularization and application of the FlexE technology, and is difficult to realize the FlexE-based networking.

Disclosure of Invention

The embodiment of the invention aims to solve the technical problem that: how to implement FlexE-based networking.

According to a first aspect of some embodiments of the present invention, there is provided a network fragmentation method, including: the router obtains a Segment Routing (SR) label corresponding to the router, wherein the SR label is allocated based on time slot information of a Flexe subinterface of the router on a path of the network fragments; the router sends the SR label of the router to other routers in the network; the router acquires SR labels sent by other routers in the network; and responding to the router as a head-end router, the router inserts a label forwarding stack into the message, wherein the label forwarding stack is generated based on the SR label on the path of the network fragment through which the message flows, so that other routers forward the message based on the label forwarding stack.

In some embodiments, the SR tag is assigned by the router or a controller of the router based on the time slot information of the FlexE subinterface of the router on the path of the network slice.

In some embodiments, the SR label corresponding to the router is an adjacency label Adjacent Segment of a link to which the router is connected.

In some embodiments, the network fragmentation method further comprises: and responding to the condition that a user defines the physical interface as a Flexe mode to generate a Flexe subinterface and allocates bandwidth for the Flexe subinterface, and allocating corresponding time slots for the Flexe subinterface by the router.

In some embodiments, the network fragmentation method further comprises: the router receives the message; responding to the router as a head end router, and determining the service type of the message by the router; the router acquires a path of the network fragment through which the message flows according to the service type of the message.

In some embodiments, the SR tag value is the same as the timeslot information of the FlexE subinterface of the corresponding router on the path of the network slice.

In some embodiments, the network fragmentation method further comprises: and after each router on the path of the network fragment through which the message flows receives the message, popping up first time slot information in a label forwarding stack, and forwarding the message to a link corresponding to the popped time slot information.

According to a second aspect of some embodiments of the present invention, there is provided a router comprising: the router label obtaining module is configured to obtain an SR label corresponding to the router, wherein the SR label is allocated based on time slot information of a Flexe subinterface of the router on a path of the network segment; the label sending module is configured to send the SR labels of the label sending module to other routers in the network; the other router label acquiring module is configured to acquire SR labels sent by other routers in the network; and the label forwarding stack insertion module is configured to insert a label forwarding stack into the message in response to the router serving as a head-end router, wherein the label forwarding stack is generated based on an SR label on a path of the network segment through which the message flows, so that other routers forward the message based on the label forwarding stack.

In some embodiments, the router further comprises: and the time slot information allocation module is configured to respond to the fact that a user defines the physical interface as a Flexe mode to generate a Flexe subinterface, allocate the bandwidth for the Flexe subinterface and allocate the corresponding time slot for the Flexe subinterface.

In some embodiments, the router further comprises: a path determination module configured to receive a message; responding to the router as a head end router, and determining the service type of the message; and acquiring a path of the network fragment through which the message flows according to the service type of the message.

In some embodiments, the router further comprises: and the message forwarding module is configured to pop up first time slot information in a label forwarding stack after receiving the message, and forward the message to a link corresponding to the popped time slot information, wherein the label forwarding stack is inserted by the head end router.

According to a third aspect of some embodiments of the present invention, there is provided a network fragmentation system, including: a plurality of any of the aforementioned routers.

According to a fourth aspect of some embodiments of the present invention, there is provided a router comprising:

a memory; and a processor coupled to the memory, the processor configured to perform any of the foregoing network fragmentation methods based on instructions stored in the memory.

According to a fifth aspect of some embodiments of the present invention, there is provided a computer readable storage medium having a computer program stored thereon, wherein the program when executed by a processor implements any one of the network fragmentation methods described above.

Some embodiments of the above invention have the following advantages or benefits: the embodiment of the invention can bear the time slot information of the Flexe subinterface through the SR label. Therefore, the transmission of the time slot information of the Flexe subinterface is realized while the label forwarding based on the SR is realized, and the networking based on the Flexe is realized.

Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a flow diagram of a network fragmentation method according to some embodiments of the invention.

Fig. 2 is a flow diagram of a network fragmentation method according to some embodiments of the invention.

Fig. 3 is a flow diagram of a router configuration method according to some embodiments of the invention.

Fig. 4A is a schematic flow chart of a message forwarding method according to some embodiments of the present invention.

Fig. 4B is an SR packet encapsulation format in some example embodiments of the invention.

FIG. 5 is an exemplary application scenario of some embodiments of the present invention.

Fig. 6 is a schematic diagram of a router according to some embodiments of the invention.

Fig. 7 is a schematic structural diagram of a network fragmentation system according to some embodiments of the invention.

Fig. 8 is a schematic diagram of a router according to further embodiments of the present invention.

Fig. 9 is a schematic diagram of a router according to further embodiments of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

Fig. 1 is a flow diagram of a network fragmentation method according to some embodiments of the invention. As shown in fig. 1, the network fragmentation method of this embodiment includes steps S102 to S108.

In step S102, the router obtains an SR tag corresponding to the router, where the SR tag is allocated based on time slot information of a FlexE (flexible ethernet) subinterface of the router on a path of the network segment. The slot information may be, for example, a slot number.

In some embodiments, the SR tag value is the same as the timeslot information of the FlexE subinterface of the corresponding router on the path of the network slice. The SR tag can thus reflect the slot information of the FlexE subinterface more directly.

In some embodiments, the SR tag is assigned by the router or a controller of the router based on the time slot information of the FlexE subinterface of the router on the path of the network slice. That is, the router may assign the SR tag by itself, or may be assigned collectively by the controller of the router.

In step S104, the router transmits its own SR tag to other routers in the network.

In step S106, the router acquires SR labels transmitted by other routers in the network.

Steps S104 and S106 may be performed in any order, or simultaneously. In some embodiments, each router may distribute the SR label through IGP (Interior Gateway Protocol).

In step S108, in response to the router acting as a head-end router, the router inserts a label forwarding stack into the packet, where the label forwarding stack is generated based on an SR label on a path of the network segment through which the packet flows, so that other routers forward the packet based on the label forwarding stack.

Since the SR tag is allocated based on the timeslot information of the FlexE subinterface, the timeslot information of each FlexE subinterface is also reflected in the tag forwarding stack. The router forwards the message based on the label forwarding stack, which is equivalent to forwarding the message based on the time slot information, that is, forwarding the message to the path corresponding to the label in the corresponding time slot.

By the method of the above embodiment, the timeslot information of the FlexE subinterface may be carried by the SR tag. Therefore, the transmission of the time slot information of the Flexe subinterface is realized while the label forwarding based on the SR is realized, and the networking based on the Flexe is realized.

In some embodiments, the SR label corresponding to the router is an adjacency label (adjacentsegment) of a link to which the router is connected. An embodiment of the network fragmentation method of the present invention is described below with reference to fig. 2.

Fig. 2 is a flow diagram of a network fragmentation method according to some embodiments of the invention. As shown in fig. 2, the network fragmentation method of this embodiment includes steps S202 to S208.

In step S202, the router allocates Adjacent Segment of the link to which the router is connected according to the time slot information of the FlexE subinterface of the router on the path of the network Segment. For example, the Adjacent Segment may be equal to the slot information of the FlexE subinterface.

In step S204, the router sends its Adjacent Segment to other routers in the network.

In step S206, the router acquires the Adjacent Segment sent by other routers in the network.

In step S208, in response to the router acting as the head-end router, the router inserts a label forwarding stack into the message, where the label forwarding stack is generated based on the Adjacent Segment on the path of the network Segment through which the message flows, so that other routers forward the message based on the label forwarding stack.

Adjacent Segment is a local tag, valid locally. Because Flexe is based on an interface and the Adjacent Segment is used for guiding the message to pass through a specific node and a specific port, the Adjacent Segment is more suitable for realizing network fragmentation, and the change of the existing protocol is small in the realization process.

In some embodiments, the router may also be pre-configured. An embodiment of the router configuration method of the present invention is described below with reference to fig. 3.

Fig. 3 is a flow diagram of a router configuration method according to some embodiments of the invention. As shown in fig. 3, the router configuration method of this embodiment includes steps S302 to S304.

In step S302, the user defines the physical interface as a FlexE mode to generate a FlexE subinterface and allocates bandwidth to the FlexE subinterface. In addition, the information of IP address, protocol, service and the like of the Flexe subinterface can be configured.

In step S304, the router allocates a corresponding time slot to the FlexE subinterface. Thus, through the allocated time slots, the router can determine the time slot information, such as the time slot number, corresponding to the FlexE subinterface.

Thus, the SR tag may be assigned based on the above configuration result.

An embodiment of the message forwarding process of the present invention is described below with reference to fig. 4A.

Fig. 4A is a schematic flow chart of a message forwarding method according to some embodiments of the present invention. As shown in fig. 4A, the message forwarding method of this embodiment includes steps S402 to S410.

In step S402, the head-end router receives the packet.

In step S404, the head-end router determines the service type of the packet. In some embodiments, the head-end router may determine the traffic type, e.g., whether it is video traffic, whether it needs to go through a firewall, etc., based on the IP five-tuple information in the packet.

In step S406, the head-end router acquires a path of the network segment through which the packet flows according to the service type of the packet. The determination process of the path of the network segment may be completed by the router itself or by the controller. In some embodiments, the path may be calculated from a full network topology.

In step S408, the head-end router inserts a label forwarding stack into the packet, where the label forwarding stack may be a Segment List (Segment List), where the label forwarding stack includes time slot information of each FlexE sub-interface on a path of the network Segment through which the packet flows, and the time slot information is arranged in order.

From the SR label forwarding perspective, the SR label on the forwarding path is included in the label forwarding stack. Since the SR label and the timeslot information are associated, the label forwarding stack also includes timeslot information of each FlexE subinterface on the forwarding path.

Fig. 4B is an SR packet encapsulation format in some example embodiments of the invention. As shown in fig. 4B, the Segment field includes four fields of a label Value, an EXP (priority), an S (bottom of stack), and a TTL (time to live), wherein the timeslot information of the FlexE subinterface is stored in the label Value field, that is, the label Value field is redefined. The EXP may take the value 111, for example.

In step S410, after each router on the path of the network segment through which the message flows receives the message, a first SR label in the label forwarding stack is popped up, and the message is forwarded to a link corresponding to the popped SR label.

In some embodiments, when the SR tag value is the same as the timeslot information of the FlexE subinterface of the corresponding router on the path of the network segment, after receiving the packet, each router on the path of the network segment, which is equivalent to the path through which the packet flows, pops up the first timeslot information in the tag forwarding stack, and forwards the packet to the link corresponding to the popped timeslot information.

When the router forwards the message based on the SR label, the router can forward the message according to the normal label popping and forwarding process. However, since the SR label has been given the meaning of the time slot information, the router actually performs forwarding according to the time slot information, thereby implementing FlexE-based networking and network fragmentation.

Some embodiments of the invention are described below in connection with an exemplary application scenario. As shown in fig. 5, routers R1 to R5 exist in the network, and R1 is the head-end router. There are two paths in the network, a FlexE Group 1 path represented by a solid line and a FlexEGroup 2 path represented by a dashed line. The Flexe Group 1 path comprises R1, R2, R3 and R5, and the Flexe Group2 path comprises R1, R2, R4 and R5. The FlexE subinterface identifications of the different routers on each path constitute a time slot combination.

The slot combination of the Flexe Group 1 path comprises 101,201 and 301, namely SR labels of links R1-R2, R2-R3 and R3-R5 on the Flexe Group 1 path are 101,201 and 301 respectively. The slot combination of the FlexE Group2 path includes 102,202,402, i.e. the SR labels of the links R1-R2, R2-R4, R4-R5 on the FlexE Group2 path are 102,202,402, respectively.

When forwarding the message, the service platform of the network may issue the optimal path to R1 in a static or dynamic manner. Assuming that the optimal path is a Flexe Group 1 path, R1 inserts a label forwarding stack {101,201,301} into the message. The R1 pops up the first time slot information 101 and forwards the message to the R2 corresponding to 101; r2 pops up the first time slot information 201 in the label forwarding stack {201,301}, and forwards the message to R3 corresponding to 201; r3 pops up the first time slot information 301 in the list {301}, and forwards the message to R5 corresponding to 301. Similarly, assuming that the optimal path is a Flexe Group2 path, R1 inserts a label forwarding stack {102,202,402} into the packet. The R1 pops up the first time slot information 102 and forwards the message to the R2 corresponding to the 102; r2 pops up the first time slot information 202 in the label forwarding stack {202,402}, and forwards the message to R4 corresponding to 202; r4 pops up the first slot information 402 in the list {402}, and forwards the message to R5 corresponding to 402. In fig. 5, the list shown above each router is a label forwarding stack in a message on a FlexE Group 1 path acquired by the router, and the list shown below each router is a label forwarding stack in a message on a FlexE Group2 path acquired by the router.

An embodiment of the router of the present invention is described below with reference to fig. 6.

Fig. 6 is a schematic diagram of a router according to some embodiments of the invention. As shown in fig. 6, the router 600 of this embodiment includes: the router tag obtaining module 6100 is configured to obtain an SR tag corresponding to a router, where the SR tag is allocated based on time slot information of a FlexE subinterface of the router on a path of a network segment; a label sending module 6200, configured to send its SR label to other routers in the network; the other router tag obtaining module 6300 is configured to obtain SR tags sent by other routers in the network; a label forwarding stack insertion module 6400 configured to insert a label forwarding stack into the packet in response to the router acting as a head-end router, where the label forwarding stack is generated based on an SR label on a path of the network segment through which the packet flows, so that other routers forward the packet based on the label forwarding stack.

In some embodiments, router 600 further comprises: the time slot information allocating module 6500 is configured to allocate a corresponding time slot to the FlexE subinterface in response to the user defining the physical interface as a FlexE mode to generate the FlexE subinterface and allocating a bandwidth to the FlexE subinterface.

In some embodiments, router 600 further comprises: a path determination module 6600 configured to receive a message; responding to the router as a head end router, and determining the service type of the message; and acquiring a path of the network fragment through which the message flows according to the service type of the message.

In some embodiments, router 600 further comprises: the message forwarding module 6700 is configured to pop up first timeslot information in a label forwarding stack after receiving the message, and forward the message to a link corresponding to the popped timeslot information, where the label forwarding stack is inserted by the head-end router.

An embodiment of the network sharding system of the present invention is described below with reference to fig. 7.

Fig. 7 is a schematic structural diagram of a network fragmentation system according to some embodiments of the invention. As shown in fig. 7, the network slicing system 70 of this embodiment includes a plurality of routers 700, and the specific implementation of the router 700 may refer to the router 600 in the embodiment of fig. 6, which is not described herein again.

Fig. 8 is a schematic diagram of a router according to further embodiments of the present invention. As shown in fig. 8, the router 80 of this embodiment includes: a memory 810 and a processor 820 coupled to the memory 810, the processor 820 configured to execute the network fragmentation method in any of the foregoing embodiments based on instructions stored in the memory 810.

Memory 810 may include, for example, system memory, fixed non-volatile storage media, and the like. The system memory stores, for example, an operating system, an application program, a BootLoader (BootLoader), and other programs.

Fig. 9 is a schematic diagram of a router according to further embodiments of the present invention. As shown in fig. 9, the router 90 of this embodiment includes: the memory 910 and the processor 920 may further include an input/output interface 930, a network interface 940, a storage interface 950, and the like. These

interfaces

930, 940, 950 and the memory 910 and the processor 920 may be connected, for example, by a bus 960. The input/output interface 930 provides a connection interface for input/output devices such as a display, a mouse, a keyboard, and a touch screen. The network interface 940 provides a connection interface for various networking devices. The storage interface 950 provides a connection interface for external storage devices such as an SD card and a usb disk.

An embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored, where the computer program is executed by a processor to implement any one of the foregoing network fragmentation methods.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable non-transitory storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A method of network fragmentation, comprising:

responding to the situation that a user defines a physical interface as a Flexe mode to generate a Flexe sub-interface and allocates bandwidth for the Flexe sub-interface, and allocating a corresponding time slot for the Flexe sub-interface by a router;

the method comprises the steps that a router obtains a Segment Routing (SR) label corresponding to the router, wherein the SR label is allocated based on time slot information of a flexible Ethernet (Flexe) subinterface of the router on a path of a network fragment;

the router sends the SR label of the router to other routers in the network;

the router acquires SR labels sent by other routers in the network;

in response to the router acting as a head-end router, the router inserts a label forwarding stack into the packet, where the label forwarding stack is generated based on an SR label on a path of the network segment through which the packet flows, so that other routers forward the packet based on the label forwarding stack.

2. The network fragmentation method of claim 1, wherein the SR label is assigned by the router or a controller of the router based on time slot information of a Flexe subinterface of the router on a path of the network fragmentation.

3. The network fragmentation method of claim 1, wherein the SR label corresponding to the router is an adjacency label Adjacent Segment of a link to which the router is connected.

4. The network fragmentation method of claim 1, further comprising:

the router receives the message;

responding to the router as a head end router, and determining the service type of the message by the router;

the router acquires a path of the network fragment through which the message flows according to the service type of the message.

5. The network fragmentation method of any of claims 1 to 4, wherein the SR tag value is the same as the time slot information of the Flexe subinterface of the corresponding router on the path of the network fragment.

6. The network fragmentation method of claim 5, further comprising:

and after each router on the path of the network fragment through which the message flows receives the message, popping up first time slot information in a label forwarding stack, and forwarding the message to a link corresponding to the popped time slot information.

7. A router, comprising:

the time slot information allocation module is configured to respond to the fact that a user defines a physical interface as a Flexe mode to generate a Flexe sub-interface, allocate bandwidth to the Flexe sub-interface and allocate a corresponding time slot to the Flexe sub-interface;

the router tag obtaining module is configured to obtain an SR tag corresponding to a router, wherein the SR tag is allocated based on time slot information of a flexible Ethernet Flexe subinterface of the router on a path of a network fragment;

the label sending module is configured to send the SR labels of the label sending module to other routers in the network;

the other router label acquiring module is configured to acquire SR labels sent by other routers in the network;

and the label forwarding stack insertion module is configured to insert a label forwarding stack into the message in response to the router serving as a head-end router, wherein the label forwarding stack is generated based on an SR label on a path of the network segment through which the message flows, so that other routers forward the message based on the label forwarding stack.

8. The router of claim 7, wherein the SR label is assigned by the router or a controller of the router based on time slot information of a Flexe subinterface of the router on a path of the network slice.

9. The router of claim 7, wherein the SR label corresponding to the router is an adjacency label Adjacent Segment of a link to which the router is connected.

10. The router of claim 7, further comprising:

a path determination module configured to receive a message; responding to the router as a head end router, and determining the service type of the message; and acquiring a path of the network fragment through which the message flows according to the service type of the message.

11. The router according to any one of claims 7 to 10, wherein the SR tag value is the same as the timeslot information of the FlexE subinterface of the respective router on the path of the network slice.

12. The router of claim 11, further comprising:

and the message forwarding module is configured to pop up first time slot information in a label forwarding stack after receiving the message, and forward the message to a link corresponding to the popped time slot information, wherein the label forwarding stack is inserted by the head end router.

13. A network sharding system comprising:

a plurality of routers as claimed in any of claims 7 to 12.

14. A router, comprising:

a memory; and

a processor coupled to the memory, the processor configured to perform the network fragmentation method of any of claims 1-6 based on instructions stored in the memory.

15. A computer-readable storage medium, on which a computer program is stored which, when executed by a processor, implements the network fragmentation method of any of claims 1 to 6.