CN113114563B

CN113114563B - Traffic back-off delay method, device and storage medium based on segmented routing strategy

Info

Publication number: CN113114563B
Application number: CN202110400806.XA
Authority: CN
Inventors: 唐寅; 江逸茗; 张进; 马海龙; 韩伟涛; 谢记超; 张鹏
Original assignee: Network Communication and Security Zijinshan Laboratory
Current assignee: Network Communication and Security Zijinshan Laboratory
Priority date: 2021-04-14
Filing date: 2021-04-14
Publication date: 2022-10-21
Anticipated expiration: 2041-04-14
Also published as: CN113114563A

Abstract

The invention discloses a flow back-off delay method, a device and a storage medium based on a segmented routing strategy, wherein the method comprises the following steps: expanding a candidate path template of the defined SRPolicy, adding a delay back-switching time parameter in the candidate path template, newly adding a Sub-TLV (Sub-threshold value) in a tunnel encapsulation attribute of BGPSRPpolicy to support parameter transmission of the SRPolicy, transmitting the SRPolicy parameter to a repeater through BGPSRpolicy expansion, checking whether a RetrieveTime value of a current effective candidate path of the SRPolicy is 0 or not when a detection mechanism informs that service flow can be back-switched, displaying the effective condition of the current main and standby candidate paths of the SRPolicy when the detection mechanism informs that the service flow can be back-switched, and displaying back-switching waiting residual time, wherein the effective/standby candidate paths of the SRPolicy are in effect. The invention solves the problem of frequent switching of service flow when the link/node frequently fails and recovers through the expansion of the SRpolicy candidate path template and the corresponding expansion of the tunnel encapsulation attribute in the BGPSRPpolicy.

Description

Traffic back-off delay method, device and storage medium based on segmented routing strategy

Technical Field

The invention relates to the field of network communication, in particular to a flow back-off delay method, a storage medium and a device based on a segmented routing strategy.

Background

The source routing mechanism of the segmented routing guides the message to pass through the network by packaging an ordered instruction list at the head node. Converting the user's intent into a Segment list, the Segment list being an ordered list of segments, wherein each Segment represents a particular operation; then the edge device guides the flow to the path corresponding to the Segment list, and the Segment route can be divided into two scenes, namely Segment Routing MPLS and Segment Routing IPv6, and an SR Policy model;

BGP SR Policy: segment Routing usually combines with an SDN controller to implement a source Routing function and issue SR Policy, and besides netconf and PCEP channels, the Segment Routing may also implement issue of candidate paths of SR Policy by using an extension of BGP;

draft-ietf-idr-segment-routing-te-Policy-09 defines the extension of BGP SR Policy, SR Policy dynamically generated on a controller is transmitted to a repeater through BGP extension, the new definition of SAIF value 73 is realized through a newly defined BGP SR Policy address family. A BGP SR Policy address family neighbor is established between the controller and the repeater, so that the controller can issue SR Policy to the repeater, the capability of network automation deployment of SR Policy is improved, the BGP SR Policy address family newly defines an NLRI format, and newly defines a tunnel encapsulation attribute subtype. The contents of SR Policy are encoded in the tunnel encapsulation attribute using the new tunnel type TLV, in the format:

the range and meaning of each attribute are the same as those of the next field in the SR Policy architecture, and in the tunnel encapsulation attribute TLV, a plurality of Sub-TLVs are further defined for representing detailed parameters of candidate paths, including priority, segment list and the like.

The SR Policy allows a plurality of candidate paths to be included, and the candidate path with low priority can be used as a backup of the active candidate path. For services requiring high-reliability protection, multiple candidate paths under an SR Policy architecture may be used to implement reliable protection for the services.

When detecting that the primary active candidate path has a fault, switching the service flow from the primary active candidate path to a backup candidate path; and when detecting that the active candidate path is restored, the service flow can be restored to the active candidate path.

When a link/node in a network frequently fails and recovers, for example, link oscillation occurs and the node frequently fails and recovers, frequent switching and switching back of candidate paths of SR Policy occurs, which causes frequent switching of service traffic on multiple candidate paths of SR Policy, and increases instability of network service.

Uncertainty also exists in the timing of the detection mechanism for the back-off, and besides the commonly used mechanisms such as SBFD/NQA, other detection mechanisms may also be used for detecting candidate paths of the segment routing SR Policy. There may be the following: the detection mechanism considers that the main path has been restored, and actually some intermediate node/link in the candidate path of SR Policy still has a problem; after the notification is switched back, the service flow is interrupted.

When an entry as above is received via BGP SR Policy, if checked valid, a candidate path for the SR Policy is generated; and multiple candidate paths corresponding to the SR Policy can be received through the BGP SR Policy, and an active candidate path and a backup candidate path are determined according to a selection rule of the candidate paths, and for this case, a traffic cutback delay method, a storage medium, and an apparatus based on a segment routing Policy are proposed.

Disclosure of Invention

The invention aims to provide a flow back-switching time delay method, a storage medium and a device based on a segmented routing strategy, which solve the problem of frequent switching of service flow when a link/node frequently breaks down and recovers through the expansion of an SR Policy candidate path template and the expansion of tunnel encapsulation attributes in corresponding BGP SR policies; the problem of accuracy of a detection mechanism in judging the back-switching time can be corrected, the flexibility and customization of reliability protection and back-switching by using the main and standby candidate paths under an SR Policy framework are improved, and various complex back-switching situations of service flow can be dealt with. And the integrity of the function is promoted through the SR Policy template and the extension of the BGP SR Policy address cluster tunnel encapsulation attribute.

The purpose of the invention can be realized by the following technical scheme:

the method comprises the steps of expanding a candidate path template of the SR Policy, adding a time delay back-switching time parameter in the candidate path template, providing richer choices for switching time among a plurality of candidate paths, and better implementing the configuration management of the SR Policy through the expanded template;

for the tunnel encapsulation attribute extension of the BGP SR policy protocol, newly adding a Sub-TLV (Sub-TLV) representation field 'Retrieve Time' for representing the delayed back-switching Time in the candidate path; therefore, the delay switching-back time of the SR Policy can be issued through a BGP SR Policy protocol by a third-party network element such as a controller, and the adaptive capacity of the repeater to the northbound protocol is improved.

When the detection mechanism informs that the service flow can be switched back, checking whether the Retrieve Time value of the current effective candidate path of the SR Policy is 0, and if the Retrieve Time value is 0, immediately switching back to the main candidate path; if the value is not 0, switching back to the main candidate path after waiting the Retrieve Time;

promoting the state display of whether the candidate path is effective or not, displaying the effective condition of the current main/standby candidate path of the SR Policy, and displaying the back-switch waiting residual time, so that a user can better perceive the back-switch state of the current candidate path;

furthermore, in the step, a master-slave path exists in a head-end device, after the master-slave switching occurs, when the detection mechanism notifies that the back-switch is possible, a delay back-switch waiting time in the backup candidate path is triggered, and the back-switch is performed after the time.

The invention has the beneficial effects that:

1. the invention solves the problem of frequent switching of service flow when the link/node frequently fails and recovers through the expansion of the SR Policy candidate path template and the expansion of the tunnel encapsulation attribute in the corresponding BGP SR Policy;

2. the invention can correct the accuracy problem of the detection mechanism to the judgment of the back-cut opportunity;

3. the invention improves the flexibility and customization of reliability protection and switching back by using the main and standby candidate paths under the SR Policy architecture, and can cope with various complex service flow switching back conditions. And the integrity of the function is promoted through the SR Policy template and the extension of the BGP SR Policy address cluster tunnel encapsulation attribute.

Drawings

The invention will be further described with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a template for extended SR Policy according to the present invention;

FIG. 2 is a schematic representation of a template for Sub-TLV of the present invention;

FIG. 3 is a schematic diagram of the definition of the extended Sub-TLV of the present invention for "Retrieve Time";

FIG. 4 is a schematic flow chart of the implementation of the flow back-off delay design based on the segment routing strategy according to the present invention;

FIG. 5 is a schematic diagram of a failure of link 2-3 on the primary path according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of the present invention when the failure of the link 2-3 on the original main path is recovered;

FIG. 7 is a schematic diagram of the present invention when the timer of Retrieve Time 20000ms times out.

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. 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 flow back-cut delay design, storage medium and device based on the segmented routing strategy comprise the following steps:

the method comprises the following steps: and expanding a candidate path template of the SR Policy defined by draft-ietf-spring-segment-routing-Policy-08 and draft-ietf-idr-segment-routing-te-Policy-09, adding a delay back-cut time parameter in the candidate path template, and newly adding a Sub-TLV (threshold value limit) in the tunnel encapsulation attribute of the BGP SR Policy for representing the delay back-cut time in the candidate path.

The head end equipment has a main/standby path, after the main/standby switching occurs, when the detection mechanism informs that the switching can be performed, the delay switching-back waiting time in the backup candidate path is triggered, and the switching-back is performed after the time.

Expanding the template of SR Policy, as shown in FIG. 1, adding a "Retrieve Time" field in the candidate path, where the Time is used to indicate the waiting Time after the detection mechanism notifies the switchback, and the unit is second;

the effective condition is as follows: the candidate path is a backup path and the main/standby switching has already occurred, and the detection mechanism informs the original main path to take effect when the original main path is recovered.

When set to 0: indicating that the terminal is not waiting and switching back directly;

when set to non-0: indicating that a switchback is to be made after waiting this time.

Step two: tunnel encapsulation attribute extension

The draft-ietf-idr-tunnel-encaps defines the tunnel encapsulation attribute of the BGP; the draft-ietf-idr-segment-routing-te-Policy-09 expands the attribute to support the parameter transmission of SR Policy; transmitting the data to the repeater through BGP SR policy extension;

draft-ietf-idr-segment-routing-te-Policy-09 defines a plurality of Sub-TLVs for tunnel encapsulation attributes, which are used to represent detailed parameters of SR Policy candidate paths, such as Binding SID, preference, priority, etc., and the Sub-TLVs follow the format shown in FIG. 2.

The Sub-TLV is extended herein for the definition of "Retrieve Time" to denote the delayed cutback Time, as in fig. 3.Type field, 1 byte, value 17; length is Length field, 1 byte, value is 2; 2 bytes, representing the cutback latency in milliseconds.

Step three: backup candidate path switchback flow

When the detection mechanism informs that the service flow can be switched back, checking whether the Retrieve Time value of the current effective candidate path of the SR Policy is 0, and if the Retrieve Time value is 0, immediately switching back to the main candidate path; if the value is not 0, switching back to the main candidate path after waiting the Retrieve Time; if the candidate path which is currently effective is detected to have a fault in the waiting time, the main path is immediately switched back to, and the flow is implemented as shown in fig. 4.

Step four: operation, maintenance and management

When the detection mechanism notifies that the service traffic can be switched back, the effective condition of the current active/standby candidate path of the SR Policy should be displayed, whether the active candidate path is effective or the standby candidate path is effective, and the remaining time of the back-switching waiting should be displayed, so that the user can sense the back-switching state of the current candidate path and the back-switching time.

Example 1

As shown in fig. 5,

nodes

1, 2, 3, 4, and 5 are in a Segment Routing network domain, SR Policy is configured on a head-end node 1, and active/standby candidate paths are configured, a main path is 1-2-3, a standby path is 1-4-5, a Retrieve Time value configured for the standby candidate path is 20000ms, and when a link 2-3 on the main path fails, service traffic is quickly switched to the standby path 1-4-5.

As shown in fig. 6, when the failure of link 2-3 on the original primary path is recovered, the detection mechanism running on the head-end node 1 detects that the primary path is recovered; at the moment, SR Policy starts to run a timer with a Retrieve Time of 20000ms to wait, and the service flow still runs in the original backup path 1-4-5 within 20000 ms.

As shown in fig. 7, when the timer of Retrieve Time 20000ms times out, SR policy performs a back-cut, and then the traffic flow switches back to the original main path 1-2-3.

An electronic device comprises a memory, a processor and a computer program stored on the memory and capable of running on the processor, wherein the processor executes the program to realize the above traffic switching delay method based on the segmented routing strategy. The memory can be various types of memory, such as random access memory, read only memory, flash memory, and the like. The processor may be various types of processors, such as a central processing unit, a microprocessor, a digital signal processor, or an image processor.

A computer-readable storage medium having stored thereon computer-executable instructions for performing the above method for traffic cutback latency based on a segment routing policy.

In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing shows and describes the general principles, principal features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed.

Claims

1. The flow back-off delay method based on the segmented routing strategy is characterized by comprising the following steps of:

the method comprises the following steps: expanding a candidate path template of SR Policy, adding a delay back-cut Time parameter in the candidate path template, and newly adding and defining a Sub-TLV in a tunnel encapsulation attribute of BGP SR Policy, wherein the Sub-TLV is used for representing the delay back-cut Time in the candidate path;

step two: the tunnel encapsulation attribute extension defines the tunnel encapsulation attribute of BGP; extending the attribute to support parameter transmission of SR Policy; transmitting the data to the repeater through BGP SR policy extension;

step three: backup candidate path switching back flow;

when the detection mechanism informs that the service flow can be switched back, checking whether the delayed switching back Time value of the current effective candidate path of the SR Policy is 0 or not, and if the delayed switching back Time value is 0, immediately switching back to the main candidate path;

if the value is not 0, switching back to the main candidate path after waiting for the Retrieve Time;

step four: operation, maintenance and management;

when the detection mechanism informs that the service flow can be switched back, the effective condition of the current main/standby candidate paths of the SR Policy is displayed, namely the effective main candidate path/standby candidate path, and the remaining time of the switching-back waiting is displayed.

2. The method according to claim 1, wherein a primary/secondary path exists in a head-end device, and after the primary/secondary switching occurs, when a detection mechanism notifies that the switching can be performed, a delay switching-back waiting time in the backup candidate path is triggered, and the switching-back is performed after the time elapses.

3. The method for delaying traffic back-cut based on segment routing Policy according to claim 1, wherein a "Retrieve Time" field is added to the candidate path in the template of the extended SR Policy in the first step, and the Time is used to indicate the waiting Time of the detection mechanism after notifying back-cut and is measured in seconds; the effective conditions are as follows: the candidate path is a backup path and the main/standby switching has already occurred, and the detection mechanism informs the original main path to take effect when the original main path is recovered.

4. The method of claim 1, wherein a plurality of Sub-TLVs are defined for tunnel encapsulation attribute in the second step, and are used to indicate detailed parameters of SR Policy candidate paths.

5. The method of claim 4, wherein the Sub-TLV is extended in the second step for defining "Retrieve Time" and is used to indicate the Time for delaying the back-cut.

6. The method according to claim 1, wherein in step three, if a failure of the currently valid candidate path is detected within the delay back-off Time Retrieve Time, the main path is immediately back-off.

7. The method for delaying traffic back-off based on the segment routing policy of claim 3, wherein when Sub-TLV is set to 0 in the first step: indicating that the terminal is not waiting and switching back directly; when set to non-0: indicating that a switchback is to be made after waiting this time.

8. A readable storage medium storing computer-executable instructions for implementing the traffic cutback delay method of any one of claims 1 to 7 when executed by a computer.

9. Traffic cutback delay equipment based on a segmented routing strategy comprises a memory, a processor and a computer program which is stored on the memory and can run on the processor, wherein the processor executes the program to realize the traffic cutback delay method according to any one of claims 1 to 7.