KR100602889B1 - A virtual protection method and means for the fiber path - Google Patents

Abstract

The present invention relates to a virtual protection method of an optical fiber path. In the method, the optical port is physically divided into a plurality of minimum protection units. Based on the minimum protection unit, the system is divided into one or more logical systems. In a logical system, each node can work in one of four working modes: normal work mode, pass through mode, bridge work mode, and switchover mode. If there is a need to provide protection, the multiplexer protection step, the sub-network connection protection step, or the channel protection step will switch the node from the normal operation mode to the other three operation modes. The invention also relates to a virtual protection device of the optical fiber path. The use of the method and apparatus according to the present invention not only solves the problem of conventional protection schemes, but also facilitates transmission networking, which can meet the increasing user demands.

Fiber Optic Path, Virtual Protection Device, Logic System, Work Page, Page Analyzer, Switch Controller, Cross-Connect Panel

Description

A VIRTUAL PROTECTION METHOD AND MEANS FOR THE FIBER PATH

The present invention relates to a virtual protection method and apparatus of an optical fiber path, and more particularly, to an extended protection scheme based on various current protection methods for SDH (synchronous digital layer) optical fiber networks such as protocol protection and channel protection. To provide.

At present, the demand for network bandwidth is high and due to the advantages of SDH transmission, the scale of fiber optic network is rapidly and continuously expanding. As a result, the self-healed protection of the fiber optic network has also become more important. According to the ITU-T standard, main protection schemes of the SDH optical fiber transmission network include channel protection, multiplex section protection, and sub-network connection protection. Among other things, multiplexer protection is the most popular protection scheme for current transport networks, which includes 1 + 1 linear multiplexer protection, 1: N linear multiplexer protection, and 2/4 fiber unidirectional / bidirectional multiplexer sharing. Includes protection.

The basic principle of the multiplexer protection is to transfer the switching information in K1 / K2 bytes of the SDH frame to realize the protocol switching function. However, since K1 / K2 bytes are located in the multiplexer of the SDH frame, only one set of K1 / K2 bytes can be transmitted to one strand of optical fiber or one optical port. This means that one strand of optical fiber must belong to one multiplexer system, that is, a conventional multiplexer is based on an optical port. On the protection mode, there is a disadvantage in that proper protection cannot be flexibly realized on the basis of different services, resulting in waste of VC (virtual container) 4 resources on the optical port. The reason why there are so many SDH protection modes is the need to apply different protection schemes for different application situations. For applications that require a short switching time, for example a switching time of less than 20ms, multiplexer protection may not meet the requirements, in which case it is necessary to employ channel protection. In addition, the multiplexer switch has the inherent drawback of its protocol byte, i.e., only 4 bits are used to indicate the node number, and one ring has a maximum of 16 nodes (except REG nodes, ie relay nodes). Can only support. If the number of nodes in the ring exceeds 16, you have no choice but to use another protection mode. In addition, in the network topology shown in FIG. 1, node A, node B, node C, and node D make up ring 101, and node A, node B, node D, and node E connect ring 102; If the ring 101 employs multiplexer protection or channel protection, the service between node B and node E or the service between node D and node E cannot be protected. Similarly, if ring 102 employs multiplexer protection or channel protection, the service between Node B and Node C or the service between Node D and Node C cannot be protected.

Indeed, this phenomenon is very common as SDH networks become more complex.

It is an object of the present invention to provide a virtual protection method and apparatus for an optical fiber path in order to solve the above problems. Not only is protection more seamless and networking is seamless, it also provides a protection mode that perfectly meets your needs.

The virtual protection method of the optical fiber path according to the present invention includes the following steps.

That is, a. Physically dividing the optical port into a plurality of minimum protection units;

b. Dividing the minimum protection unit having one or more protection channels on each optical port into one or more portions to form one or more logic systems;

c. Each node in each logical system working in a normal working mode;

d. In the event of a failure in the optical fiber link between two nodes in one of the one or more logical systems, if the input side working optical fiber link fails, the node of the logical system is switched from the normal working mode to the switching working mode, and the output working If a fiber link fails, switching a node of the logical system from the normal working mode to a bridged working mode and switching another node of the logical system from the normal working mode to a pass through mode.

 The switching in the switching step may be a multiplexer protection switch, a sub-network connection protection switch, a channel protection switch, or another protection switch capable of realizing the same function.

The switching in the converting step means multiplexing unit protection switching, and the step d includes the following steps.
That is, d1. Creating a logical system for protection switching;

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d2. For each of the generated logical systems, generating four sets of pages of normal work pages, conversion pages, bridge pages, and pass pages;

d3. Send the transition page to a node in the logical system to switch to the transition work mode, send the bridge page to the node to switch to the bridge work mode, and send the pass page to the node to pass the work mode Switching to.

Here, step d3 may include: passing a pass page to the current node directly from the node's input protection bus to the node's output protection bus; If a bridging page is sent to the current node, connecting the node's input working bus to the node's output protection bus; And if the switching page is sent to the current node, connecting the node's input protection bus to the node's output work bus.

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In this way, the minimum protection unit is VC4 or VC3, and in step b, one or more VC4 or VC3 may consist of one or more logical systems.

In this way, if a protection transition is performed in either of the logical systems, only the services that cannot be transmitted normally of the logical system can be included in the protection transition.

The optical fiber path virtual protection device according to the present invention,
A page analyzer for generating a normal working page, a passing page, a bridged page, and a conversion page corresponding to each logical system;
A conversion controller which stores the generated page by the page analyzer and transmits corresponding normal work pages, passing pages, bridged pages, and conversion pages according to the conversion status; And

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The normal work page, the pass page, the bridge page, and the switch page are transmitted by the switch controller, and upon receiving the normal work page, the input work bus and the output work bus of the current node are connected, and when the pass work page is received, The input protection bus and the output protection bus of the current node are connected, and upon receiving the switch page, the input protection bus and the output work bus of the current node are connected. When the bridge node is received, the input work bus of the current node is connected. And a cross connection panel connecting the output protection bus.

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Using this approach, the optical port can be divided into a plurality of logical systems because the logical system can be separated based on the minimum protection unit such as VC4, VC3, etc., so that the optical port can have a plurality of minimum protection units. As a result, different services can flexibly choose different protection modes, and different logical systems (different services, different networks) can use different transition conditions. In this way, transport networking is smoother and protected mode is more in line with user needs. Since the same system can be divided into a plurality of logical systems that can employ different protection modes, the disadvantage that the system must be this protection mode or the low protection mode is overcome. In this way, more nodes may be included in the protection system. For example, node E in FIG. 1, which cannot be protected by the conventional mode, may be protected according to the present invention. It can be seen that the protection according to the invention is more flexible, comprehensive and satisfactory.

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1 is a diagram showing that two rings cannot be protected at the same time.

2 is a diagram illustrating that different services use different protection modes.

3 is a diagram of a bus crossing method of an embodiment of the present invention.

4 is a diagram illustrating execution of unidirectional multiplexer switching in an embodiment of the present invention.

5 is a diagram for a multiplexer switching algorithm of the present invention.

6 is a diagram of conventional networking.

7 is a diagram illustrating the division for a logical system of virtual path protection.

8 is a diagram showing the structure of the virtual protection device of the optical fiber path of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

As shown in FIG. 2, the present invention can realize protection of various services such as a video service, a voice service, a signal service, and an overseas service. Different services may employ different protection modes. The core idea of the technical method according to the present invention is as follows.

The first idea is the concept of minimum protection unit. This is based on the fact that the optical port can be physically divided into a plurality of VC4 and the minimum protection unit is one VC4. For example, an optical port with a transmission rate of 62 Mbit / s can be viewed as four independent VC4 since its transmission payload is four VC4.

The second idea is the concept of a bus. The SDH transmission system can be largely divided into branch units, line units, and cross-connection units. The logic system of the present invention is the division of the line unit and the branch unit. The switching page described below is generated by this division, and the conversion pages generated according to different divisions are different. Switching execution is mainly carried out by the cross connection unit. In add / drop multiplex (ADM) facilities, there are many types of services that can be added or branched, for example, 2Mbit / s, 34Mbit / s, 155Mbit / s, etc. Capacities on the line can be 155 Mbit / s, 622 Mbit / s, 2.5 Gbit / s, and so on. Different cross-connected units cannot be selected if the lines have different capacities or different add and branch services. When a low priority service is added on the line, it is multiplexed to VC4, and using time-division cross-connect unit at the intersection, services entering into the expected VC4 from different VC4s are subject to adjustment of the time-division cross-connect unit. To cross on the VC4. Here, VC4 is the basic speed of the bus unit. 3 shows the meaning of this bus crossing. In FIG. 3, the left part of the arrow indicates three different VC4s, that is, VC4 # 1, VC4 # 2, and VC4 # 3, wherein the blocks filled with diagonal lines each represent the second unit (1, 2) of the first VC4, The second units 2, 3 of the second VC4 and the third units 3, 1 of the third VC4 are displayed, respectively. The right part of the arrow indicates that after the bus time-sharing cross-connection, the SDH system multiplexes the services coming from three different VC4s into one VC4, in order (3,1), (1,2), (2,3) It is shown sending a service loaded on.

The third idea is the concept of logical systems. Since a node can be dependent on different basic network topology structures, and the protection modes on each network can be different, the logical system is viewed collectively by physical media with the same basic topology, the same level, and the same protection mode. It is called a (logic-system). Attributes of logical systems include, for example, levels of 155M, 622M, 2500M, etc., network element types such as add / branch multiplexers (ADM), terminals (TM), players (REG), for example unidirectional or Service direction, such as bidirectional, for example, channel protection, multiplexer protection, 1 + 1 protection, 1: N protection, protection modes such as subnetwork connection protection, for example, the number of optical fibers such as two or four, and rings There are basic network topology types, such as links and links. The ADM logic system includes an east direction line, a west line and a selectable branch. The TM logic system includes trend / west lines and selectable lines. By these attributes, the logical system can be analyzed for add / branch services or passing services to generate work pages and protected pages. The concept of a logical system simplifies service deployment and at the same time offers the possibility for smooth implementation of protection.

When a protection transition occurs in one logical system, if other logical systems do not satisfy the logical system protection transition triggering condition, only services on the logical system participate in the protection transition process, i.e., logical independence exists. do.

The fourth idea is the concept of bus replacing. Multiplexer switching can be performed by the idea of changing one node to bridge mode, the other node to switch mode, and the intermediate node to pass-through mode. The method shown in Fig. 4 showing the embodiment can be adopted. The left part of the arrow in FIG. 4 is the network topology, which represents two fiber rings representing the working channel and the guard channel, respectively, and four nodes A, B, C, and D on the ring. In FIG. 4, the right arrow indicates the working state of the working channel and the protection channel of the three nodes of the passing node, the bridging node, and the switching node, among which, the white block indicates the working channel and the hatched block protects it. Display the channel. If a failure occurs in the optical fiber 401 between two nodes of B and C, the working channel and the protection channel between B and C are no longer active. In this case, the transmission service between two nodes of B and C or the transmission service through node B and node C is transmitted to the destination node through the protection channel between BA, AD and DC. At this time, node B is bridged and node C is switched and node A and D are pass-through, that is, node A and node D are pass-through nodes, node B is a bridged node, and node C is a switch node. In this embodiment, 1 to 4 of each node are the input buses of the working channel, 1 'to 4' are the output buses of the working channel, 5 to 8 are the input buses of the protection channel, and 5 'to 8' are the protection buses. It is an output bus of the channel, and at this time, as can be seen in FIG. 4, at the passing nodes (for example, nodes A and D), signals input from the input buses 5, 6, 7, 8 on the protection channel are received. It intersects the output buses 5 ', 6', 7 ', 8' on the guard channel, and for bridged nodes (e.g., Node B), the output buses 1 ', 2', 3 ', 4 on the working channel. The signal originally output from ') is sent to the output buses (5', 6 ', 7', 8 ') on the protection channel, and for the switching node (e.g. node C), the input bus (1) on the working channel The signals originally input from 2, 3, 4 are converted into input buses 5, 6, 7, 8 on the protection channel.

Since each node can handle all transition situations, each node needs to prepare four sets of pages: normal page, passing page, bridged page, and conversion page. Normal pages are generated by analysis of the logical system, and all other pages are based on bus replacement with normal pages. In the present invention, "replacement" and "switching" are two different concepts, in which replacement is a numerical meaning, for example, replacement of input bus 1 with output bus 9, the conversion refers to a network element, specifically It refers to the operation adopted by the logic system, for example, that multiplexer switchover occurs in the logical system, but it does not mean that multiplexer replacement occurs in the logical system, but the switchover refers to the transition from the working part to the protected part.

Based on the above concept, the virtual protection method of the optical fiber path of the present invention includes the following steps.

a. Physically divide the optical port into one or more minimum protection units.

b. Depending on the service requirements, the minimum protection units of the plurality of protection channels of each optical port are divided into different logical systems to form one or more logical systems, and the optical ports are divided into a plurality of different logical systems.

c. In each logical system, each node can work in one of four working modes: normal work mode, pass through mode, bridge work mode, and switch work mode.

d. If protection is needed, normal operation All the multiplexer transitions are made to switch to the other three modes of operation.

The fifth idea is the concept of protection independence. Different protection characteristics have different protection conditions. The channel protection is based on the auxiliary unit alert indication signal (TU-AIS) on the path. The multiplexer protection is based on the alarm indication signal (MS-AIS) or the like on the multiplexer. Different protections are logically dependent on different network topologies and typically take different physical paths, so protection does not occur at the same time. Therefore, if the protection of one logical system is required, it does not affect the working mode of the other logical system.

5 is a simple flowchart for implementing the multiplexer switching algorithm of the present invention. First, create a logical system of multiplexer protection. Then, based on the batch, four sets of work pages are analyzed: normal work pages, conversion pages, bridged pages, and passing pages. The normal work page is from the input work bus to the output work bus, the transition page is from the input protection bus to the output work bus, the bridged page is from the input work bus to the output protection bus, and the pass page is from the input protection bus to the output protection bus. Until. This type of node is analyzed by the protection switch controller. If this node is a bridging node, a bridging page is sent, replacing the output work bus with the input protection bus. If the node is a switching node, it sends a switching page and replaces the output protection bus with the input work bus. If the node is a pass node, it passes a pass page, and the input protection bus passes directly to the output protection bus. As shown in FIG. 4, when a failure occurs in the optical fiber between node B and node C and multiplexer switching is required, the system analyzes the normal work page and the location of the failure of each node to the node A to node D. Analyze what happens. After analysis, if node A and node D are found to be pass-through nodes, node B is a bridged node, and node C is a transition node, send pass-through pages to node A and node D, send bridge pages to node B, Send the conversion page to node C. From this switching algorithm, it can be seen that the bus switching is different from the conventional switching scheme (all VC4 on the optical port participate in the switching), and participating in the switching is the VC4 belonging to the logical system. Therefore, the number of VC4 participating in the conversion can be arranged based on the request, so that another VC4 can be used for other protection.

6 is a topology diagram of a network used in any province of the prior art. According to the counterclockwise direction, network elements A, B, C, D, E, F, and G constitute a ring 601, and network elements H, I, J, K, L, M, N, and O are rings 602, the two rings are connected via G, H and F, I. The services in the ring 601 and the ring 602 can be protected by adopting the multiplexer protection mode or another protection mode, but the services between the rings cannot be protected.

In the optical fiber ring shown in Fig. 7, the ring has the same networking topology as in Fig. 6, but any portion of the optical fiber network can be protected because the logical system partitioning of the present invention is used. In FIG. 7, the virtual ring 701 is composed of the network elements A, B, C, D, E, F, and G according to the counterclockwise direction, and the network elements H, I, J, K, L, M, Constitute a virtual ring 702 with N, and O, one large with network elements A, B, C, D, E, F, G, H, I, J, K, L, M, N, and O Configure the virtual ring 703. Virtual ring 701 and virtual ring 702 protect multiple services in a ring using multiplexer protection, and virtual ring 703 uses channel protection to protect services between rings. In this scheme, each node deploys two logic systems and maps all VC4s of each optical fiber to the multiplexer logic system according to the demand of the service, or some of the VC4s of each optical fiber are multiplexed logic system Can be mapped during In the logical system constituting the virtual ring 703, the logical system generally occupies a large number of connected nodes and also has a lot of channel protection, so that one or more of all optical ports are generally dependent on the number of services and the optical port level. VC4 are mapped into the logical system.

8 illustrates a structure of a virtual protection device for realizing the virtual protection method according to the present invention. The virtual protection device of the optical fiber path includes at least three parts of the page analyzer 801, the switching controller 802 and the cross connection panel 803. Each node sends the appropriate work page according to the current switching state, to make the appropriate bus connection. Among them, the page analyzer 801 analyzes the layout of the logic system, generates four work pages of a normal work page, a pass page, a bridged page, and a conversion page, and also stores the work page in the conversion controller 802. It is used to Since each node has a plurality of logical systems, there are many sets of pages, all of which are related to the logical system. The switch controller 802 is used to send the work page to the cross connect panel 803 according to the switch state. The cross connection panel 803 performs the connection of the corresponding bus, and thus performs the switching operation in this way.

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited thereto.

Claims (10)

In the virtual protection method of the optical fiber path, a. Physically dividing the optical port into a plurality of minimum protection units; b. Dividing the minimum protection unit having one or more protection channels on each optical port into one or more portions to form one or more logic systems; c. Each node in each said logical system working in a normal working mode; d. If a failure occurs in an optical fiber link between two nodes in one of the one or more logical systems, if an input side working optical fiber link fails, the node of the logical system is switched from the normal working mode to the switching working mode, and the output side If a working optical fiber link fails, switching a node of the logical system from the normal working mode to a bridged working mode and switching another node of the logical system from the normal working mode to a pass through mode. Fiber path virtual protection method comprising a. The method of claim 1, The switching in the switching step is a multiplexing protection switching, a sub-network connection protection switching, or a channel protection switching, characterized in that the virtual path protection. The method of claim 1, The switching in the switching step is a multiplexer protection conversion, Step d is, d1. Creating a logical system for protection switching; d2. For each of the generated logical systems, generating four sets of pages of normal working pages, conversion pages, bridged pages, and passing pages; d3. Send the transition page to a node in the logical system to switch to the transition work mode, send the bridge page to the node to switch to the bridge work mode, and send the pass page to the node to pass the work mode Steps to Switch Fiber path virtual protection method comprising a. The method of claim 3, Step d3, When the pass page is sent to a current node, passing directly from the node's input protection bus to the node's output protection bus; Connecting the node's input working bus to the node's output protection bus when the bridged page is sent to the current node; And Connecting the node's input protection bus to the node's output working bus when the switching page is sent to the current node. The optical fiber path virtual protection method further comprising. The method of claim 1, The minimum protection unit is VC4 or VC3, And in step b, at least one VC4 or VC3 consists of at least one logical system. The method of claim 1, And when protection switching is performed in any one of the logical systems, only the services that cannot be transmitted normally of the logical system are included in the protection switching. delete In the virtual protection device of the optical fiber path, A page analyzer for generating a normal working page, a passing page, a bridged page, and a conversion page corresponding to each logical system; A conversion controller for storing the generated page by the page analyzer and transmitting a corresponding normal work page, a pass page, a bridged page, and a conversion page according to a conversion state; And The normal work page, the pass page, the bridge page, and the switch page are transmitted by the switch controller, and upon receiving the normal work page, the input work bus and the output work bus of the current node are connected, and when the pass work page is received, The input protection bus and the output protection bus of the current node are connected, and upon receiving the switch page, the input protection bus and the output work bus of the current node are connected. When the bridge node is received, the input work bus of the current node is connected. And cross-connect panels for connecting output protection buses Fiber path virtual protection device comprising a. delete delete

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