WO2007009347A1

WO2007009347A1 - A method and apparatus for transmitting service stream on a virtual interchange system

Info

Publication number: WO2007009347A1
Application number: PCT/CN2006/001593
Authority: WO
Inventors: Xiaojun Duan; Lingyuan Fan; Yuepeng Chen; Dengchao Wu; Meng Ke
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2005-07-15
Filing date: 2006-07-06
Publication date: 2007-01-25
Also published as: CN1897567A; CN100486216C

Abstract

A method and apparatus for improving transmission reliability of virtual interchange system. Its key point is as follows: when selecting service stream path, the connection controlling layer selects more than two transmission paths simultaneously for the service stream and determines the primary path; once the primary path is in failure condition, the bearing ability layer can switch service stream to the alternate path automatically, thus failure restoring ability of the bearing ability layer of V-Switch is achieved. The invention reduces risk of service interruption, improves reliability of private line service, and enhances stability of network running. The invention applies to network of any size, tends to realization ,maintenance and management.

Description

TECHNICAL FIELD The present invention relates to the field of network communication technologies, and in particular, to a method and an apparatus for transmitting a service flow in a virtual switching system.

BACKGROUND OF THE INVENTION With the increasing scale of the Internet, various network services are rushing to emerge, and advanced multimedia systems are emerging one after another. Since multimedia services take up a large amount of bandwidth, it is difficult to obtain reliable transmission of key services to be guaranteed by existing networks. As a result, various QoS (Quality of Service) technologies have emerged. Portal-based applications and services as well as broadband multimedia services, including rich video (video) / audio (audio) streaming, VOD (video on demand), video multicast, multimedia interaction, high bandwidth requirements for ordinary residential users Games; provide video conferencing, distance education, VPN (virtual private network), data line with QoS guarantee for business users, and become an important part of broadband operation.

For these commercial users, VPN/VPDN (Virtual Dial-up Private Network) dedicated line schemes such as V-Switch (Virtual Switching), L2TP (Layer 2 Tunneling Protocol), and MPLS (Multi-Protocol Label Switching) are proposed. The V-Switch technology is mainly used to build a stable, practical, and economical carrier-class metro Ethernet. It can implement QoS guarantee, network security protection, carrier-class network maintenance and management functions, and has number-based user management and certain Core business management capabilities such as mobility, centralized management of business open management billing, and services such as intelligent Layer 2 traffic scheduling, LAN (local area network) private line, and IP traffic planning, which have filled the current network in pure two. Insufficient layering ability.

As shown in Figure 1, the V-Switch system is divided into three layers: the V-Switch service control layer, the V-Switch connection control layer, and the V-Switch bearer capability layer. The service control layer completes the control of the service and the registration of the V-Switch private line, etc.; the connection control layer is used to maintain the exchange resources in the DRE (data forwarding entity), including devices, ports, links, VLANs (virtual local area networks), and accepts service control. The V-Switch establishment request of the layer SCR (service control registration), the service flow path is selected for the V-Switch connection, the bandwidth and the VLAN (virtual local area network) resource are allocated, and the control information is sent to the DRE device through which the service flow passes; DRE is in the bearer capability layer, and it is set according to the connection control layer. The VLAN switch entry completes the forwarding of the service flow in the Ethernet frame format. The VLAN switch entries are as follows:

The DRE uses the VLAN switch table as the routing basis for service flow forwarding. The forwarding process of the service data is described as follows: The Ethernet frame of ID1 of the VLAN received in port 1 is sent to port 2, and the ID 1 of the VLAN is converted into the ID 2 of the VLAN; and the VLAN ID received in port 2 is received. When the Ethernet frame of 2 is sent to port 1, the ID2 of the VLAN is converted into the ID1 of the VLAN. In this form, a virtual channel of a VLAN can be established throughout the network. The virtual channel is described as:

[Device 1, Port 1, VLAN ID 1] [Device 1, Port 2, VLAN ID 2] [Device 2, Port 3, VLAN ID 2] [Device 2, Port 1, VLAN ID 3]... .

In the above-mentioned service data forwarding process, the bearer capability layer itself has no fault recovery mechanism. Once a physical link between the DREs of the bearer capability layer fails, the V-Switch leased line service is removed, that is, when the bearer capability layer detects the virtual channel state failure. When the connection is closed and all the affected resources are released, the service is interrupted and the reliability of the leased line service is reduced.

Summary of the invention

The present invention provides a method and apparatus for transmitting a traffic flow in a virtual switching system to improve the reliability of transmission in a virtual switching system.

The technical solution of the present invention includes: A method for transmitting a service flow in a virtual switching system, comprising:

The connection control layer selects two or more equivalent transmission paths for the service flow, determines the primary path, and sends the path selection message including the primary and secondary path information to the data forwarding entity DRE of the bearer capability layer;

DRE selects the primary path to transport the traffic.

The process of selecting an equivalent transmission path for a service flow is:

The connection control layer preferentially selects a path with a different DRE sequence as the equivalent transmission path, and secondly selects a path with the same DRE sequence but different physical links as the equivalent transmission path.

The path selection message delivery process specifically includes: sending, by the VSC of the connection control layer, the path information to the DRE in the form of a flow mapping command.

The process of determining the primary path includes:

The connection control layer determines the path priority according to the number of DREs in the path, and specifies a shortest path with less DRE as the primary path, and the rest is the backup path.

The method further includes: determining a priority of the backup path according to the number of DREs, and the priority of the backup path with a small number of DREs is relatively high.

The method further includes: performing fault detection on the primary path and the backup path for performing service transmission in the virtual switching system; and switching the service to the backup when determining that the primary path is faulty and the backup path is normal Transfer on the path.

The process of switching from the primary path to the backup path is to select the highest priority backup path to switch according to the priority of the backup path in the non-faulty backup path.

The path switching process is initiated by the first and last DREs of the transport service flow and is transparent to the connection control layer.

The method further includes: when the primary path is normal and the backup path is faulty, the service bearer is not switched, only the failed backup path is recorded.

An apparatus for transmitting a service flow in a virtual switching system, comprising: a transmission path selection module connected to a control layer, and a data forwarding entity DRE of a bearer capability layer, where

The transmission path selection module is configured to select two or more equivalent transmission paths for the service flow, determine the primary path, and send the path selection message including the primary and secondary path information to the data forwarding entity DRE of the bearer capability layer. ; The DRE selects an active path to transport a service flow.

The device further includes: a link failure detecting module and a path switching module, wherein the link fault detecting module is configured to perform fault detection on the primary path and the backup path for performing service transmission in the virtual switching system; When the primary path is faulty and the backup path is normal, the path switching module is notified to perform the switching operation. When it is determined that the primary path is normal and the backup path is faulty, the service bearer is not switched, and only the failed backup path is recorded;

The path switching module is configured to switch the service to a backup path according to the received handover notification.

The process of selecting an equivalent transmission path for a service flow is:

The connection control layer preferentially selects a path with a different DRE sequence as an equivalent transmission path, and secondly selects a path with the same DRE sequence but different physical links as an equivalent transmission path.

As can be seen from the technical solution provided by the present invention, the present invention enables the bearer capability layer to have a fault recovery function. When a physical link between DREs on the primary path fails, the backup path mechanism is used to quickly switch services. On the backup path, the reliability of the transmission in the virtual switching system is improved, the risk of service interruption of the leased line is reduced, the reliability of the leased line service is improved, and the stability of the network operation is enhanced. The present invention is applicable to networks of any size, is easy to implement, and maintains management.

DRAWINGS

1 is a schematic diagram of a prior art V-Switch architecture;

2 is a schematic diagram of a backup path of a bearer capability layer according to an embodiment of the invention;

3 is a flow chart of a backup path operation in a virtual switching system according to an embodiment of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The core idea of the present invention is: When a connection control layer selects a service flow path, it selects two or more transmission paths for the service flow at the same time, and determines one of the primary paths, and the rest is a backup path, once the primary path is used. In the event of a fault, the service flow layer can be automatically switched to the backup path to carry the fault recovery capability of the bearer capability layer of the V-Switch.

2 is a schematic diagram of a backup path of a bearer capability layer according to an embodiment of the present invention, and FIG. 3 is a flowchart of a backup path operation according to an embodiment of the present invention. The present invention is described below with reference to FIGS. 2 and 3. One: 3 one

The process of transmitting a service flow is described.

The V-Switch system in the embodiment shown in FIG. 2 and FIG. 3 includes a service control layer, a connection control layer, and a bearer capability layer, where the service control layer and the connection control layer may be one physical entity or two separate physical entities. . The three representative entity names are SCR (V-Switch Service Control Entity), VSC (V-Switch Connection Control Entity), and DRE. The method for transmitting a service flow in the virtual switching system includes:

Step 10: The VSC selects two or more equivalent paths for the service flow;

One or more links exist between the two DREs on the bearer capability layer. Each link carries at least one V-Switch leased line service. Each V-Switch leased line service is distinguished by a specific connection identifier. - The switch private line can carry the service flow data. Before the bearer capability layer sends the data, the connection control layer VSC first selects the path. When the VSC selects the path, if it is a cross-domain situation, it needs to cooperate with other VSCs to complete the path selection. At the same time, two or more equivalent paths are selected for the service flow, and are sent to the bearer capability layer in the form of a flow mapping command, and the service flow is identified by the bearer capability layer ^^ flow mapping information, and the traffic is divided, and The sent path is carried. The equivalent paths are mutually backup relationships, and there is no case where every DRE node and each link on the path are identical between any two equivalent paths. In this case, first ensure that the DRE sequences on different paths are as different as possible. Secondly, when the DREs are the same, the links between the DREs should be guaranteed to be different. The specific method is that each VSC tries to select a path without the same DRE in the routing process. Secondly, if the DRE cannot be avoided, then different links between the same DRE should be selected, for example, links E and F in FIG. It is two different links; that is, the paths with different DRE sequences are preferentially selected, and the paths with the same DRE sequence but different physical links are selected, but the end-to-end link overlap of the two paths cannot occur.

Using the above principles, the fault recovery method can be implemented in two cases: The first is that when a DRE on the primary path fails, it can be switched to the backup path that does not pass the DRE; the second is if the DRE is not faulty. If a link on the DRE is faulty, you can switch to another backup link of the DRE to carry the bearer. If no backup link is available, you can switch to the backup path that does not pass the DRE.

For example, referring to FIG. 2, it is assumed that the connection control layer selects a service flow path for a dedicated line between the user terminal 1 (UE1) and the UE2, and may follow the above-mentioned routing principle at the initial DRE 1 and terminate the DRE6. At the same time, two or more paths are selected end-to-end. Here, two paths are used. The first one is that the links ^ D, F, and H are connected end to end to form a path. The DRE sequence of the service flow is: <DRE1, DRE2, DRE4, DRE5, DRE6>; The second is a path consisting of 6 links A, C, E, G, K, and L. The DRE sequence of the service flow is: DRE1, DRE3 DRE4, DRE5, DRE7, DRE8, DRE6>.

Step 11: Determine the priority of the selected path above;

After the path is selected, the priority of the path is determined. The path priority can be determined according to the number of DREs passing through the path, that is, the length of the path. When the path selection message is sent by the connection control layer, a DRE number is specified. The shortest path is the primary path, and the rest is the backup path. The backup path can also determine the priority of the backup path according to the number of DREs. The priority of the backup path with a small number of DREs is relatively high. The principle of shortest priority of the path, the above example can determine that the priority of the first path is higher than the priority of the second path.

Step 12: Deliver the selected path message to the bearer capability layer.

The VSC sends the path information to each DRE in the form of a flow mapping command, where the flow mapping command includes a session ID, a flow information, a quality of service Qos parameter, a traffic descriptor, an ingress port name of the DRE, and a virtual local area network VLAN. ID, outgoing port name, and outgoing VLAN ID. When the VSC delivers the path, the first path is specified as the primary path, because the path has fewer DREs than the second one, the path is relatively short, and the second is the backup path. The connection control layer sends the path selection message. On each DRE of the bearer capability layer, it is guaranteed that the service flow can have two paths for carrying. At this time, the traffic between UE1 and UE2 is carried only on the first path.

Step 13: Detecting a link failure, and switching the bearer path when the primary path fails;

The first two DREs on the path periodically initiate end-to-end link detection messages, such as the two DREs of the two paths in Figure 2: DRE 1 and DRE6 need to periodically detect the access of the full path, is there a In the case of a local link failure, once any link on the two paths fails, the two DREs at the beginning and the end of the link can be automatically detected, and the link failure information is automatically notified to the surrounding DREs. There are various implementation methods for link fault detection in the industry, which are not the focus of the present invention, so the present invention will not be described in detail.

If the primary path is faulty and the backup path is normal, the primary (first) path is switched to the backup (second) path. After the successful handover, the backup path becomes the primary path. The primary path before the occurrence becomes the backup path. When there are multiple backup paths, the optimal backup path is selected according to the priority of the backup path to switch, that is, the backup path with the higher priority is selected for switching. The first and last DREs are used to initiate the handover, which is transparent to the connection control layer, and the connection control layer does not interfere; if the primary path is normal and the backup path is faulty, only the failed backup path is recorded, and the bearer of the service is not switched; When determining the primary path failure, if there is no normal backup path, the leased line is removed. Therefore, when the selected path message is sent by the connection control layer, the VSC specifies the primary path. At this time, the primary backup relationship is absolute, but the primary path that is initially delivered by the VSC fails, and after switching to the backup path, this The future primary path and backup path are relative, that is, the path of the current bearer service is the primary use, it may not be the shortest path, and the other backup path may be the shortest path. The path switching process may be transparent to the connection control layer, and may not notify the connection control layer, but may also notify the connection control layer of an event, so that the connection control layer and the service control layer perform some policy adjustment.

In summary, the present invention implements the V-Switch fault recovery function, and selects more than two paths at the same time by using the connection control layer to be routed to the bearer capability layer, and the bearer capability layer selects the path priority level. The high-priority path carries the bearer, and the bearer capability layer detects the link fault through the link detection technology. Once the link fault causes the primary path to fail, the service is switched to the backup path with the highest priority to continue the bearer. The recovery speed of the leased line is reduced, the risk of service interruption of the leased line is reduced, and the fault recovery capability of the V-Switch private line service is improved. The backup path technology is applicable to networks of any size, is easy to implement, and performs maintenance management.

The present invention also provides an apparatus for transmitting a service flow in a virtual switching system, comprising: a transmission path selection module connected to the control layer and a data forwarding entity DRE of the bearer capability layer.

The foregoing transmission path selection module is configured to select two or more equivalent transmission paths for the service flow, determine the primary path, and deliver the path selection message including the primary and secondary path information to the data forwarding entity DRE of the bearer layer. The process of selecting the equivalent transmission path for the service flow is as follows: Connection The control layer preferentially selects the path with the different DRE sequence as the equivalent transmission path, and secondly selects the path with the same DRE sequence but different physical links as the equivalent transmission path.

The above DRE selects the primary path to transport the service flow.

The device of the present invention further includes: a link failure detecting module and a path switching module, wherein 001593

-8 - a link fault detection module, configured to perform fault detection on the primary path and the backup path for performing service transmission in the virtual switching system; and when the primary path is determined to be faulty and the backup path is normal, the path switching module is notified to perform Switching operation; When it is determined that the active path is normal and the backup path is faulty, the bearer of the service is not switched, and only the faulty backup path is recorded.

The path switching module is configured to switch the service to the backup path according to the received handover notification.

As for the method for determining the primary and secondary paths, the priority of the primary and secondary paths, the path switching process, and the like are completely the same as those of the previous method, and are not described here.

The above is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or within the technical scope disclosed by the present invention. Alternatives are intended to be covered by the scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

Rights request

A method for transmitting a service flow in a virtual switching system, comprising: the connection control layer selecting two or more equivalent transmission paths for the service flow, determining the primary path, and including the primary and secondary path information. The path selection message is sent to the data forwarding entity DRE of the bearer capability layer;

DRE selects the primary path to transport the traffic.

2. The method of transmitting a service flow in a virtual switching system according to claim 1, wherein the process of selecting an equivalent transmission path for the service flow is:

The method for transmitting a service flow in the virtual switching system according to claim 1, wherein the path selection message delivery process specifically includes:

The V-Switch connection control entity VSC connected to the control layer sends the path information to the DRE in the form of a flow mapping command.

The method for transmitting a service flow in a virtual switching system according to claim 1, wherein the determining the primary path includes:

The method for transmitting a service flow in a virtual switching system according to claim 4, wherein the method further comprises: determining a priority of the backup path according to the number of DREs, and a priority of the backup path with a small number of DREs. Relatively high.

The method for transmitting a service flow in a virtual switching system according to any one of claims 1 to 5, wherein the method further comprises:

In the virtual switching system, fault detection is performed on both the primary path and the backup path used for service transmission;

When it is determined that the primary path is faulty and the backup path is normal, the service is switched to the backup path for transmission.

The method for transmitting a service flow in a virtual switching system according to claim 6, wherein the process of switching from the primary path to the backup path is performed in the non-faulty backup path according to The priority of the backup path is used to select the highest priority backup path to switch.

The method of transmitting a service flow in a virtual switching system according to claim 6 or 7, wherein the path switching process is initiated by a first-to-last DRE of the transport service flow and is transparent to the connection control layer.

The method for transmitting a service flow in a virtual switching system according to claim 6, wherein the method further comprises:

When the primary path is normal and the backup path is faulty, the bearer of the service is not switched, only the backup path of the fault is recorded.

An apparatus for transmitting a service flow in a virtual switching system, comprising: a transmission path selection module connected to a control layer, and a data forwarding entity DRE of a bearer capability layer, wherein the transmission path selection module is configured to: The service flow selects two or more equivalent transmission paths, determines the primary path, and sends the path selection message including the primary and secondary path information to the data forwarding entity DRE of the bearer capability layer;

The DRE selects an active path to transmit a service flow.

The apparatus for transmitting a service flow in a virtual switching system according to claim 10, wherein the apparatus further comprises: a link failure detecting module and a path switching module, wherein the link failure detecting module is configured to: In the virtual switching system, the primary path and the backup path for performing service transmission are fault-detected; when the primary path is determined to be faulty and the backup path is normal, the path switching module is notified to perform the switching operation; and the primary path is determined to be normal and backed up. When the path is faulty, the bearer of the service is not switched, and only the faulty backup path is recorded.

12. The apparatus for transmitting a service flow in a virtual switching system according to claim 10, wherein the process of selecting an equivalent transmission path for the service flow is:

The connection control layer preferentially selects the path with the different DRE sequence as the equivalent transmission path, and secondly selects the path with the same DRE sequence but different physical links as the equivalent transmission path.