CN101056143A - Optical layer based protection recovery scheme of the optical Ethernet network - Google Patents

Abstract

A physical dual-route protection and recovery scheme based on optical layer. The switchover time of this solution can meet the requirements of real-time services, and the mutual protection of optical cables can be realized by combining with WDM technology. The invention is simple in design (mainly optical splitter, optical switch, and optical PIN detector), low in cost, fast in detection speed, and short in switching recovery time. Business application. There are two ways to implement this solution, one is that both the working optical fiber S and the protection optical fiber P have detection, and the other is that the protection optical fiber P has no detection. In the attached figure, both the working optical fiber S and the protective optical fiber P have detection methods.

Description

Protection and Restoration Scheme Based on Optical Layer for Optical Ethernet

Technical Field The present invention relates to an optical layer-based physical dual-routing protection recovery scheme, which belongs to the optical layer protection of optical fibers in the field of data communication.

Background technology Due to the development of municipal construction, communication line engineering maintenance departments cooperate with municipal construction to relocate, modify and cut urban optical cable lines very frequently. Planned, unplanned, pre-planned or unscheduled constructions are threatening the safety of communication pipelines and optical cable lines in them all the time. Therefore, maintenance personnel of communication line engineering are required to ensure the safety and stability of communication and reduce economic losses and adverse social impacts caused by bad communication habits during construction and troubleshooting.

At the same time, due to the fierce competition in the telecommunication market and the availability of the telecommunication network due to the growing telecommunication transmission business, the reliability puts forward higher requirements. Once a network failure occurs due to man-made reasons or accidental events, it is an urgent problem for telecom operators to minimize the impact of the failure on users or even prevent the failure from affecting users.

However, the self-protection ability of the current optical fiber transmission system is limited, and some have no self-protection ability at all, such as some access networks and some point-to-point communication environments. When a total resistance fault occurs in the optical cable line, it is difficult to ensure the safety and smoothness of the line. Another example is the automatic monitoring system for optical cable lines that has emerged and been adopted in recent years. Although it can complete real-time and automatic monitoring of optical cable lines, it cannot prevent and predict sudden blockage of optical cables caused by external forces, and cannot occur in optical cable lines. It protects the optical fiber transmission system in case of failure. That is to say, no matter which fiber optic cable is fully blocked or partially blocked, it will cause a communication interruption for a certain period of time to the optical communication system that is not protected by another physical optical cable transmission route.

At present, most of the metro trunk optical cables and user backbone optical cables have more than 24 cores, and most of the cores in the optical cables are in use. Once blocked, even if the conditions are relatively good, it will take 6h to 10h to completely repair it. Even if it is a planned cutover, under the current technical conditions, the communication must be interrupted for 1h to 6h. Therefore, it will not only have a greater impact on high-speed, broadband, and large-capacity optical fiber transmission. In order to provide users with high-quality, efficient, safe and smooth communication lines, the communication line engineering maintenance department must take more practical and effective protection measures. For example, mutual protection of physical dual routers is a very effective protection measure. Through this mutual protection, whether it is a sudden line blockage or link blockage, or the cutover of an optical cable line, there will be no obvious communication interruption or communication interruption that users can feel.

Summary of the invention The present invention proposes a physical dual-routing protection and restoration scheme based on the optical layer. The switchover time of this solution can meet the requirements of real-time services, and the mutual protection of optical cables can be realized by combining with WDM technology. Through this mutual protection scheme, whether it is a sudden line or link blockage, or a cutover of an optical cable line, there will be no obvious or user-feeling communication interruption.

The technical scheme adopted in the present invention is as follows:

Provide an optical layer protection and recovery scheme. In the specific experiment, the optical Ethernet is used to build the test environment, and the protection and recovery services at the optical layer are realized according to the principle of dual transmission and selective reception. The output signal of the optical port of the Ethernet switch is divided into two paths for transmission through the splitter, and the two paths of optical fibers are the working optical fiber S and the protection optical fiber P respectively. After S and P carry the same business and transmit it to the opposite end at the same time, they are divided into two paths again, one of which is used to connect to the optical switch, and the other is used to connect to the PIN detector for detection, and the PIN detector will detect the The signal passes through the circuit to control the optical switch and select the path to ensure that the signal can be switched to the P fiber when the S fiber is interrupted.

Provides a dual-route switching solution based on optical layer protection and restoration, which is designed for point-to-point communication protection switching to protect the physical damage of optical fibers, and is applied in non-SDH ring network environments. The working optical fiber and the protective optical fiber represent two optical cable lines with different physical routes. It can be used for the reliable access protection of the optical access network, that is, the optical fiber link protection between OLT and ONU; it can also be used as a supplementary application of other protection switching methods of the metropolitan area network or core network or directly used for the protection of the core network ; Optical path protection between important nodes and so on. At present, there are many schemes for various broadband access, but in terms of the protection switching mechanism, only the scheme at the optical layer can be compared with the self-healing function of SDH. This solution is suitable for communication environments with abundant optical fibers.

Provides a system mutual protection scheme based on wavelength division multiplexing for protection and recovery at the optical layer. It uses the difference in physical paths to realize spatial mutual protection on two optical cable lines or optical fiber transmission links. When the optical fiber is blocked or artificially interrupted, the optical switch will automatically switch under the drive of the detection control circuit, and the communication transmission will be almost unaffected, so there will be enough time for repair and cutover, thus ensuring the transmission quality.

The present invention is simple in design (mainly optical splitter, optical switch, optical PIN detector), low cost, fast detection speed, short switching recovery time, almost imperceptible to upper layer applications, very suitable for voice communication and other real-time business application.

Description of drawings

Figure 1 is a design scheme of point-to-point communication protection switching.

Fig. 2 is a point-to-point communication protection switching optical fiber P non-detection scheme.

Figure 3 is a protection scheme in the case of physical dual routing.

Figure 4 shows the protection method of system mutual protection for urban optical cables by using wavelength division multiplexing (WDM) technology.

Specific Implementation Modes In the specific optical layer protection and restoration scheme, the output signal of the optical output port of the switch is divided into two paths for transmission through a splitter, and the two paths of optical fibers are the working optical fiber S and the protection optical fiber P. After S and P carry the same business and transmit it to the opposite end at the same time, they are divided into two paths again, one of which is used to connect to the optical switch, and the other is used to connect to the PIN detector for detection, and the PIN detector will detect the The signal passes through the circuit to control the optical switch and select the path to ensure that the signal can be switched to the P optical fiber when the S optical fiber is interrupted. The signal detected by the PIN detector is first judged logically, that is, only when the working optical fiber S is interrupted and the protective optical fiber P is working normally, the circuit driving is executed to control the switching of the optical path of the optical switch.

Application of Protection Switching Scheme

The solution in Figure 1 is designed for point-to-point communication protection switching. Used to protect the fiber from physical damage. The working optical fiber and the protective optical fiber represent two optical cable lines with different physical routes. It can be used for the reliable access protection of the access network, that is, the optical fiber link protection between the OLT and the ONU; it can also be used as a supplementary application of other protection switching methods of the metropolitan area network or core network or directly used for the protection of the core network; Optical path protection between important nodes. This solution is suitable for communication environments with abundant optical fibers.

Figure 2 shows the point-to-point communication protection switching optical fiber P non-detection scheme. It is mainly for the modification of the scheme in Fig. 1, mainly because no light detection is provided for the protection optical fiber P in two directions. As a solution for optical fiber P without detection. Compared with the solution in Figure 1, the detection of the protective fiber is reduced, so the cost of the whole solution is reduced, and the optical signal fading caused by light splitting is reduced at the same time.

Figure 3 shows the protection scheme under the condition of physical dual routing. Figure 3 illustrates the protection from A to D as shown. A to D can communicate through a direct route, and communicate through a jump route between nodes B or C to protect communication. Such physical dual-routing protection well solves the breakage and damage of optical fibers.

Figure 4 shows the protection method of system mutual protection for urban optical cables using wavelength division multiplexing (WDM) technology. Figure 4 is a schematic diagram of a system with WDM transmission mutual protection between two points A and B. Optical cable S and optical cable P represent two optical cable lines with different physical routes. There may be no direct optical cable from A to B, and the optical cable line needs to pass through the intermediate office to switch and jump, so that the lengths of the two optical cable lines or optical fiber transmission links are not equal. In addition, the 4 wavelength division multiplexing mutual protection transmission system shown in Figure 4 (note: only half of the transmission system is drawn here. The other half, that is, the receiving at the A end and the sending at the B end are not drawn), at the A end, there are 4 The wavelengths emitted by the optical transceiver are λ1, λ2, λ3 and λ4 respectively. These optical signals are firstly distributed evenly through the 1/2 optical splitter, and then coupled to the corresponding optical fibers of the optical cable S and the optical cable P by WDM. On the B side, the optical signals with the same wavelength separated by two WDMs are sent to the same 1×2 optical switch.

In this way, it can be seen from the end A that the optical signals of λ1, λ2, λ3 and λ4 are usually kept in the corresponding optical fibers of the optical cable S and the optical cable P. Assume that at the B end, the optical switch is usually connected to the optical cable S, that is, the transmission between A and B is usually maintained by the optical cable S. When the optical fiber is blocked, the optical switch acts immediately, and automatically connects the λ1, λ2, λ3, and λ4 signals from the optical cable P in an instant, so that the entire system is only interrupted momentarily. At this time, the optical cable S can be repaired or cut over, while the communication transmission is almost unaffected, and the repair or cutover time can be relaxed, which ensures the quality of the repair or cutover. After the blocking repair or cutover of the optical cable S is completed, the optical switch can be manually or automatically connected back to the optical cable S (of course, the optical cable S may not be connected back), so that the line can be restored. If the fiber optic cable P is blocked or relocated and cut over, there is also the same processing process.

It can also be seen from Figure 4 that the loss of the splitter, wavelength division multiplexer and optical switch is added to the optical fiber link by using the transmission mutual protection method. For example, the loss of the 1/2 splitter is theoretically 3dB , The insertion loss of the 1×2 optical switch at the B end is ≤1.0Db (including fiber optic connectors), etc., but due to the large margin of the line loss index, it will not have a great impact on communication transmission. In addition, the switching time of the optical switch is less than or equal to 8ms, and no obvious communication interruption will be felt.

Claims (4)

1. A physical dual-route protection recovery scheme based on optical layer, characterized in that its switching time can meet the requirements of real-time business, and can realize the mutual protection of optical cables by combining with WDM technology. 2. Its switching time as claimed in claim 1 can meet the requirement of real-time business, it is characterized in that detection speed is fast, and switching recovery time is short, can almost make upper layer application feel imperceptible, is very suitable for the application of real-time business such as voice communication. 3. The scheme is simple in design, mainly composed of optical splitter, optical switch and PIN detector, and the cost is very low. 4. This solution supports the use on all-optical networks including optical fiber access networks, and can comprehensively transmit multimedia services such as voice, data, and video.

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