CN101001123B - Inversion method and device for optical transmission - Google Patents

Abstract

An embodiment of the present invention provides a switching method for an optical transmission network, wherein the optical transmission network includes a terminal A and a terminal B, and a protection channel and a working channel are established between them. When the protection channel from terminal B to terminal A fails, And when terminal B requires protection, the method includes the following steps: terminal B sends K-byte information including a bridging request through its working channel to terminal A; The protection channel and the working channel of the terminal carry services at the same time; the A terminal sends the bridged information through the protection channel to the B terminal; after receiving the bridged information, the B terminal selects and receives the service from the protection channel to complete the switchover. The embodiment of the invention also provides a switching device for an optical transmission network. The technical solution of the embodiment of the present invention improves the protection function of the multiplex section, thereby solving the problem that one end of the protection channel fails to effectively know the switching request of the opposite end.

Description

Switching method and device for optical transmission network

technical field

The present invention relates to the field of network communication, more specifically, to a switching method and device for an optical transmission network. the

Background technique

In SONET (Synchronous Optical Network, synchronous optical network), if LOS (Loss Of Signal, signal loss), LOF (Loss Of Frame, frame loss), AIS-L (Line AIS, line alarm indication signal), BER (Bit Error Ratio, bit error rate) exceeds the limit (for example, SONET regulations exceed 0.001), then SF (SignalFailure, signal failure) will be generated. the

In SONET, RDI-L (Line Remote Defect Indication, Line Remote Defect Indication) is used to indicate that the opposite end detects AIS-L, and the detected LOS and LOF will generate AIS-L. the

SDH (Synchronous Digital Hierarchy, Synchronous Digital System)/SONET path protection includes linear protection and shared protection ring, they all transmit protection information through K bytes, K bytes should be transmitted in the protection channel, and the protection channel is when switching occurs , the channels allocated for transmitting normal services. When there is no switchover, the protection channel can be used to carry additional services. When the switchover occurs, the services on the affected working channel are bridged to the protection channel for transmission. The working channel is the channel that transmits normal services when no switchover occurs. Switching refers to the action of selecting and receiving normal services from the protection channel instead of the working channel. The so-called bridging refers to the action of transmitting normal business on the working and protection channels at the same time. A shared protection ring means that the protection channels of the entire ring are shared by normal services on each working section, so the entire ring is also called a shared protection ring. the

Linear protection is divided into two architecture modes: 1+1 and 1:N. In the 1+1 architecture, the working service is permanently bridged to the working and protection channels. According to the switching mode, it can be refined into 1+1 single-ended, 1+1 double-ended, 1:N single-ended, and 1:N double-ended. the

The bridging and switching control rules of linear protection are as follows:

(1) In the 1+1 architecture, the working service is permanently bridged to the working and protection channels. the

(2) In the 1:n single-ended architecture, the service indicated by the K1 byte at the receiving side is bridged to the protection channel. the

(3) In the 1:n double-ended architecture, the bridging control is accomplished by comparing the channel numbers indicated by the receiving and sending K1 bytes. If the receiving and sending K1 bytes indicate the same working channel number, the corresponding services are bridged to the protected channel. the

(4) Single-ended operation of 1+1 architecture, the selector is controlled by the highest priority local request. the

(5) Double-ended operation in 1+1 architecture. The control of the selector is completed by comparing the channel number indicated by receiving K2 and sending K1 bytes. If the two match, the service carried on the indicated channel will be selected from the protection channel. receive. the

(6) In the 1:n architecture, the control of the selector is completed by comparing the channel number indicated by the receiving K2 byte and the sending K1 byte, if the receiving side K2 byte and the sending side K1 byte indicate the same working channel number , the service carried by the working channel is selected from the protection channel. the

The meaning of linear protection K bytes is as follows:

K1 high 4 bits K1 lower 4 bits K2 high 4 bits K2 No. 5 K2 lower 3 bits request type request bridge channel number bridged channel number 0, 1+1 architecture; 1, 1:n architecture 4: Single-ended mode 5: Double-ended mode 6: MS_RDI7: MS_AIS

Wherein, the request types include: protection locking, forced switching, signal failure, signal degradation, manual switching, practice switching, and the like. A protection lock will deny all working traffic (and additional traffic, if any) from using the protection channel. Forced switching will force the specified working service to be switched to the protection channel under the condition that the external switching command of the same or higher priority takes effect or the SF condition exists on the protection segment. Manual switching will switch the designated working service to the protection channel when there is failure or degradation on other channels (including the protection channel) or the switching command with the same or higher priority takes effect. Practice switching When the protection channel is not in use, issue this command to check the response of the APS (Auto Protection Switching, automatic protection switching) byte, but do not perform the actual switching action. the

The shared protection ring is divided into two-fiber shared protection ring and four-fiber shared protection ring. the

The meaning of the shared protection ring K byte is as follows:

K1 high 4 bits K1 lower 4 bits K2 high 4 bits K2 No. 5 K2 lower 3 bits request type destination node source node 0: short diameter 1: long diameter 0: idle 1: bridged 2: bridged switching 3: extra service on the protection channel 6: MS_RDI7: MS_AIS

Among them, the request types include: protection locking, section forced switching, ring forced switching, protection channel signal failure, signal failure section switching, signal failure ring switching, protection channel signal degradation, signal degradation section switching, signal degradation ring switching, Manual section switching, manual ring switching, section practice switching, ring practice switching, etc. A section is a collection of multiplex sections between adjacent nodes on the ring. Ring switching is applicable to two-fiber and four-fiber rings. When ring switching occurs, normal services transmitted in the direction of the failed section are switched to the protection channel on the reverse long path. Section switching is only applicable to four-fiber rings. When only the working channel fails in a section on the ring, normal services are carried by the protection channel of the same section through section switching. the

If there is already a ring switch on the ring, and a failure of the same priority occurs in another section, a ring switch is also required (including SF-R (Signal Fail-Ring, signal failure ring switch) and FS-R (Forced Switched Normal Traffic to Protection -Ring, Forced Ring Switching), then, if the priority of the bridge request is SF-R or higher, both ring switches will be performed. the

The ring should be able to protect all possible protected services, even in the case of multiple bridge requests with the same priority (including SF-R and FS-R combinations). the

For a four-fiber ring, the following combinations on the same section will cause the following situations in SF-R:

a) The working line and protection line on the same section fail;

b) Deterioration of working lines and protection lines on the same section;

c) Deterioration of working lines and failure of protection lines on the same section. the

If the node performing ring bridging and switching no longer receives valid ring bridging requests on the long path, the node should end its ring bridging and switching. the

The short-path K-byte bridging request is the only basis for section switching to be started or stopped, and the long-path bridging request is the only basis for ring switching to be started or stopped. The short path refers to the segment that initiates the bridge request. The long path refers to the channel formed by other segments on the ring that are far away from the segment that initiates the bridge request. the

When a node performing segment switching receives a long-path ring bridging request with a relatively higher priority for a non-adjacent segment, the node should discard the segment switching. the

The switching process in the prior art multiplex section protection (such as SONET architecture) will be described below with reference to the accompanying drawings. the

(1) Linear 1+1 switching process

FIG. 1 is a schematic diagram of a linear 1+1 switching process in the prior art. As shown in Figure 1, for the linear 1+1 single-ended protection mode, the selector is controlled by the local request without using K bytes. For the heterogeneous work and protection of fiber cuts described in the figure, the B-side is based on the local request ( That is, the working channel SF) selects and receives services from the protection channel;

For the 1+1 double-ended mode, since the protection channel at one end has failed, the working channel should not be protected. the

(2) Linear 1:N single-ended switching process

FIG. 2 is a schematic diagram of a linear 1:N single-ended switching process in the prior art. Single-ended switching refers to a protection switching architecture in which only the affected direction is switched to the protection channel for a unidirectional failure. Double-ended switching refers to a protection switching architecture in which both directions (including the affected direction and the unaffected direction) are switched to the protection channel for a unidirectional failure. the

As shown in Figure 2, the B side detects SF, and the switching establishment process is as follows:

a) Terminal B sends K bytes to node A on the protection channel (the existing technology stipulates that K bytes should be transmitted on the protection channel) to request A to bridge the service carried on channel 1, that is, to send the lower four bits of K1 in K bytes is "0001";

b) Terminal A receives the bridging request from terminal B on the protection channel, bridges channel 1 to the protection channel, and sends K bytes to B on the protection channel to indicate that the service of channel 1 has been bridged, that is, K2 high four in the sent K bytes The bit is "0001";

c) Terminal B receives the bridging information of the 1-channel service of terminal A from the protection channel (that is, the upper four bits of K2 in the K byte are received as "0001"), and will selectively receive services from the protection channel, and the single-ended switching is completed. the

(3) Two fiber ring switching process

FIG. 3 is a schematic diagram of a two-fiber ring switching process in the prior art. In the two-fiber ring shown in Figure 3, SF is detected on both fibers in section #1<--->#2. If there is no other switching request on the ring, both #1 and #2 will The request (detected SF) requests to initiate SF-R ring switching, and can receive the request from the other party on the long path, and establish the switching according to the long path switching request;

And when there are other coexisting ring switching on the ring (SF-R, FS-R), although #1 and #2 cannot receive each other's switching request on the long and short paths, according to the local request (detected The coexistence ring switching request on the SF) and the long path can still maintain the SF-R ring switching. the

(4) Four-fiber ring switching process

FIG. 4 is a schematic diagram of a four-fiber ring switching process in the prior art. As shown in Figure 4, #2 detects the failure of the working channel (SF-S (Signal Fail-Span, signal failure section switching)) at time T1 on the four-fiber ring, and at time T2, the upper and lower eastbound rings are forced to switch at #3 (FS -R) command, #1 detects the failure of the protection channel (SF-P (Signal Fail-Protection, signal failure of the protection channel)) at time T3. According to the existing technology, the state transition on the ring is as follows:

a) At time T1, #1<--->#2 section establishes SF-S section switching, that is, #1 and #2 are in the section switching state, and #3 and #4 are in the K byte pass-through state;

b) At time T2, the FS-R ring switching in section #3<--->#4 preempts the SF-S section switching, that is, #1 and #2 are in the full pass-through state, and #3 and #4 are in the ring switching state , where, full passthrough refers to an action of sending the received K1, K2 bytes and protection channel signals as they are;

c) At time T3, #1 detects the SF-P at the local end and the MS-RDI (Multiplex Section-Remote Defect Indication) in K bytes on the working channel (MS-RDI in SDH) RDI, and the equivalent concept in SONET is RDI-L) indicates that the calculated #1<--->#2 section switching request should be SF-R, and the ring switching request (SF-R) and FS-R coexist , so #1 sends an SF-RK byte request on the long and short paths, and #2 calculates #1<--->#2 based on the SF-S detected at the local end and the SF-R switching request received on the protection channel The section switching request should be SF-R, and the ring switching request (SF-R) and FS-R coexist, so the state on the ring after time T3 is that both ring switching of SF-R and FS-R coexist. the

However, for the above-mentioned linear 1:N single-ended protection architecture, as shown in FIG. 5 , which is another schematic diagram of the linear 1:N single-ended switching process in the prior art, the inventor found the following problems during the invention process: When the protection channel in the receiving direction of terminal A fails, the working channel of terminal B also fails, and the services carried by the working channel of A-->B should be transmitted through the protection channel in the same direction. However, according to the rule of "in the 1:n single-ended architecture, the service carried by the working channel indicated by the K1 byte on the receiving side is bridged to the protection channel", the switchover cannot be established because the protection channel in the receiving direction of the A end is invalid and cannot obtain B Of course, it is impossible to know the "working channel indicated by the K1 byte", thus causing A-->B service interruption. the

Similarly, if end B has an external switching command to switch to the protection channel, if the protection channel in the receiving direction of end A fails, it will not be able to obtain the switching request of end B and cannot complete the bridging action, and finally end B cannot establish switching. Wherein, the external switching commands include commands such as protection locking, forced switching, manual switching, and practice switching. the

In addition, for the above-mentioned four-fiber ring, as shown in FIG. 6, FIG. 6 is another schematic diagram of a four-fiber ring switching project in the prior art. The inventor also found the following problem during the invention process: at time T3, the The MS-RDI indicated in the K byte of the working channel, #1 finally calculates the coexistence of FS-R and SF-R ring switching, however, there is a certain uncertainty with the help of MS-RDI, in SONET, and MS-RDI The equivalent concept is RDI-L, and there is no one-to-one correspondence between SF and RDI-L in SONET. The generation conditions of SF include LOS, LOF, AIS-L, and BER violation (specified in SONET), while only LOS, LOF, AIS-L will generate RDI-L, but BER violation will not generate RDI-L. the

If the SF detected by #2 at time T1 in Figure 6 is caused by BER OVER, then #1 will not be able to detect RDI-L on the eastbound working channel, so at time T3, #1 cannot receive the RDI-L due to failure of the eastbound protection channel For the short-path request to #2, the west direction receives the FS-R long-path K-byte request that does not point to itself, and detects SF-P by itself. Under this input combination, #1 will enter the SF-P section switching state , but cannot enter the SF-R ring switching, resulting in FS-R and SF-R not coexisting on the ring, unable to protect all services as much as possible, and does not meet the recommended specifications. It can be seen that the existing technology relying on RDI is unreliable, has certain defects, and may cause unnecessary service interruption. the

All in all, in the linear 1:N single-ended protection and four-fiber shared protection ring, if the protection channel fails, the switching request of the opposite end cannot be known, which will lead to incorrect establishment of switching in some cases. the

Therefore, people need a solution to improve the multiplex section protection function, which can solve the problems in the above-mentioned prior art. the

Contents of the invention

The embodiment of the present invention aims to provide a switching method and device for an optical transmission network, which can solve the problem that the existing linear 1:N single-ended protection and four-fiber shared protection ring cannot correctly establish switching in some cases, etc. problem, in order to improve the multiplex section protection function. the

According to an aspect of an embodiment of the present invention, a switching method for an optical transmission network is provided, wherein the optical transmission network includes a terminal A and a terminal B, and a protection channel and a working channel are established between them. When terminal B connects to terminal A When the protection channel of the end (that is, the protection channel of the receiving direction of the A end) fails, and the B end requires protection, the method comprises the following steps: the B end sends the K byte information that includes the bridging request through its working channel to the A end; the A end receives After receiving the K-byte information, designate the protection channel from terminal A to terminal B and the working channel to carry services at the same time according to the bridging request; terminal A sends the bridged information through the protection channel from terminal A to terminal B (that is, the protection channel in the sending direction of terminal A); B After receiving the bridged information, the terminal selects services from the protection channel to complete the switchover. the

In the above-mentioned switching method, the method also includes: when the B-side no longer requires protection, the B-side releases the switching, and the B-side sends the K-byte information that does not include the bridging request through its working channel to the A-side; If the received K-byte information does not include the bridging request, the protection channel bearer service designated from terminal A to terminal B is removed. the

In the above switching method, the K byte includes a K1 byte and a K2 byte, wherein the lower four bits of K1 are used to indicate the number of the requested bridged channel, and the upper four bits of K2 are used to indicate the number of the bridged channel. the

In the above-mentioned switching method, the method specifically includes: establishing a protection channel and a working channel between the A-end and the B-end of the optical transmission network according to a linear 1:N single-ended protection architecture; wherein, the protection channel from the B-end to the A-end has a signal failure, and there is a signal failure or signal degradation in the working channel from terminal A to terminal B, or terminal B receives an external switching command. the

In the above-mentioned switching method, the method specifically includes: establishing a protection channel and a working channel according to the four-fiber ring architecture between the A-end and the B-end of the optical transmission network; wherein, there is a signal failure in the protection channel from the B-end to the A-end, and the A-end There is a signal failure or signal degradation in the working channel to the B terminal, and the B terminal is in the signal failure ring switching state. the

According to another aspect of the present invention, a switching device for an optical transmission network is provided, wherein the optical transmission network includes a terminal A and a terminal B, and a protection channel and a working channel are established between each other, and the device includes: a working channel The K-byte sending module is used to instruct the B-side to send the K-byte information including the bridging request through the working channel from the B-side to the A-side when the protection channel from the B-side to the A-side fails, and the B-side requires protection; After receiving the K-byte information at the instruction end A, designate the protection channel from the A end to the B end and the working channel to carry services at the same time according to the bridging request; the response module is used to instruct the A end to send the bridged information through the protection channel from the A end to the B end; And a switching module, which is used to instruct terminal B to select and receive services from the protection channel according to the received bridged information, so as to complete the switching. the

In the above-mentioned switching device, it also includes: a recovery module, which is used to instruct the B-side to release switching when the B-side no longer requires protection, and the B-side sends K-byte information that does not include the bridging request through its working channel to the A-side , and instruct terminal A to remove the protection channel bearer service specified from terminal A to terminal B according to the received K-byte information that does not include the bridging request. the

In the above switching device, the K byte includes a K1 byte and a K2 byte, wherein the lower four bits of K1 are used to indicate the number of the requested bridged channel, and the upper four bits of K2 are used to indicate the number of the bridged channel. the

In the above switching device, a protection channel and a working channel are established between the A terminal and the B terminal according to a linear 1:N single-ended protection architecture. the

In the above switching device, a protection channel and a working channel are established between the A terminal and the B terminal according to the four-fiber ring architecture; wherein, there is a signal failure in the protection channel from the B terminal to the A terminal, and there is a signal failure in the working channel from the A terminal to the B terminal. Or the signal is degraded, and the B terminal is in the signal failure ring switching state. the

It can be seen from the above description that the embodiment of the present invention uses the working channel to send K bytes to improve the multiplex section protection function, thereby solving the problem that the end of the protection channel failure cannot effectively obtain the switching request of the opposite end. Therefore, the embodiment of the present invention has The beneficial effect is that the multiplex section protection in the following situations can be improved:

(1) In the linear 1:N single-ended protection architecture, one end has a working channel switching request, and the opposite end protection channel fails. In this case, the switching cannot be completed under the existing technology. After adopting the present invention, as long as the opposite end corresponds to the working channel Switchover can be completed without failure, so as to better realize service protection;

(2) There is SF or SD in the working channel at one end of the same section of the four-fiber ring, and only the protection channel at the opposite end fails. Under the existing technology, it can be indicated by means of RDI (MS-RDI in SDH, RDI-L in SONET) To establish and maintain switching, due to the unreliability of RDI, there are certain defects. After adopting the present invention, the coexistence of ring switching can be better ensured, and all possible protected services can be protected as much as possible. the

Other features and beneficial effects of the embodiments of the present invention will be set forth in the ensuing description and, in part, will be apparent from the description, or be learned by practice of the present invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description, claims hereof, as well as the appended drawings. the

Description of drawings

The drawings described here are used to provide a further understanding of the present invention, constitute a part of the present application, and do not constitute an improper limitation of the present invention. In the attached picture:

Fig. 1 is the linear 1+1 switching process of prior art;

Fig. 2 is the linear 1: N single-ended switching process of prior art;

Fig. 3 is the switching process of two fiber rings in the prior art;

Fig. 4 is the four-fiber ring switching process of prior art;

Fig. 5 is another schematic diagram of the prior art linear 1:N single-ended switching process;

Fig. 6 is another schematic diagram of the four-fiber ring switching project of the prior art;

Fig. 7 is the schematic diagram of the linear 1:N single-ended protection of the embodiment of the present invention;

Fig. 8 is the schematic diagram of the four-fiber ring protection of the embodiment of the present invention;

Fig. 9 is the processing flowchart of the linear 1:N single-ended protection switching of the embodiment of the present invention;

Fig. 10 is another processing flowchart of the linear 1:N single-ended protection switching of the embodiment of the present invention;

Fig. 11 is the processing flowchart of the four-fiber shared protection ring switching of the embodiment of the present invention;

Fig. 12 is the flowchart of the switching method of the embodiment of the present invention; And

Fig. 13 is a block diagram of a switching device according to an embodiment of the present invention. the

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. Here, the exemplary embodiments and descriptions of the present invention are used to explain the present invention, but not to limit the present invention. the

In the description of the background technology, the technical defects of the linear 1:N single-ended switching process and the four-fiber ring switching process are respectively analyzed. Through the above analysis, it can be known that the switching cannot be established correctly in some cases, and the root cause is the protection of the receiving direction. One end of the channel failure cannot effectively know the switching request of the other end. the

In view of the above analysis, the embodiment of the present invention provides a switching method for a communication network, and the communication network includes a terminal A and a terminal B with a protection channel and a working channel established between them. the

Embodiment one:

12 is a flowchart of a switching method according to an embodiment of the present invention, wherein the optical transmission network includes a terminal A and a terminal B, and a protection channel and a working channel are established between them. When the protection path to the A end) fails and the B end requires protection, the switching method includes the following steps:

Step S1202, terminal B sends K-byte information including the bridging request through its working channel to terminal A;

Step S1204, after receiving the K-byte information, terminal A designates the protection channel and the working channel from terminal A to terminal B to carry services at the same time according to the bridging request;

Step S1206, the A terminal sends the bridged information through its protection channel to the B terminal (that is, the transmission direction protection channel of the A terminal);

In step S1208, terminal B selects and receives services from the protection channel according to the received bridged information, so as to complete the switching. the

In the above-mentioned switching method, the following steps may also be included: when the B-side no longer requires protection, the B-side releases the switching, and the B-side sends the K-byte information that does not include a bridging request through its working channel to the A-side; For the received K-byte information that does not contain a bridging request, remove the protection channel bearer service from the designated A-side to B-side (that is, when the B-side releases the switchover, restore the K-byte information on the working channel, which is no longer the same as that sent by the protection channel. Kbytes). the

The K byte includes a K1 byte and a K2 byte, wherein the lower four bits of K1 can be used to indicate the number of the bridged channel requested, and the upper four bits of K2 can be used to indicate the number of the bridged channel. the

A protection channel and a working channel can be established between the A terminal and the B terminal according to the linear 1:N single-ended protection architecture. the

A protection channel and a working channel can also be established between the A-side and the B-side according to the four-fiber ring architecture. The working channel has SF or SD, and the switching state is the SF-R ring switching state. the

Embodiment two:

FIG. 13 is a block diagram of a switching device 1300 according to an embodiment of the present invention, wherein the optical transmission network includes a terminal A and a terminal B, and a protection channel and a working channel are established between them. The switching device 1300 includes:

The working channel K byte sending module 1302 is used for when the protection channel from the B terminal to the A terminal fails, and when the B terminal requires protection, instruct the B terminal to send the K byte information including the bridging request through its working channel to the A terminal;

The business designation module 1304 is used to instruct end A to designate the protection channel and the working channel from end A to end B to carry services at the same time according to the bridging request after receiving K bytes of information;

Response module 1306, used to instruct terminal A to send bridged information through its protection channel to terminal B;

The switching module 1308 is used to instruct terminal B to select and receive services from the protection channel according to the received bridged information, so as to complete the switching. the

In the above-mentioned switching device 1300, it may also include: a recovery module (not shown), which is used to instruct the B-side to release switching when the B-side no longer requires protection, and the B-side transmits through its working channel to the A-side without including Bridge the K-byte information of the request, and instruct the A-side to remove the protection channel bearer service designated from the A-side to the B-side according to the received K-byte information that does not include the bridge request. the

The K byte includes a K1 byte and a K2 byte, wherein the lower four bits of K1 can be used to indicate the number of the bridged channel requested, and the upper four bits of K2 can be used to indicate the number of the bridged channel. the

A protection channel and a working channel can be established between the A terminal and the B terminal according to the linear 1:N single-ended protection architecture. the

A protection channel and a working channel can also be established between the A-side and the B-side according to the four-fiber ring architecture. The working channel has SF or SD, and the switching state is the SF-R ring switching state. the

It can be seen from the above description that the embodiment of the present invention uses the working channel to send K bytes to improve the multiplex section protection function, thereby solving the problem that the end of the protection channel failure in the receiving direction cannot effectively know the switching request of the opposite end. The improvement measures of the present invention for linear 1:N single-end protection and four-fiber shared protection ring multiplex section protection will be described below with reference to the accompanying drawings and specific embodiments. the

Embodiment three:

As shown in Figure 7, Figure 7 is a schematic diagram of the linear 1:N single-ended protection of the embodiment of the present invention. For the linear 1:N single-ended protection mode, in theory, the A terminal should establish a bridge, and the B terminal should be protected from the protection mode. The service is selectively received on the channel, but on the basis of the existing technology, the bridging control of the A terminal needs to use the K byte, and the service carried by the working channel indicated by the K1 byte on the receiving side is bridged to the protection channel. Invalid, K bytes cannot be received, so the bridge cannot be established, and the one-way service cannot be protected naturally; similarly, if there is an external switching command on the B side to switch to the protection channel, the switching cannot be established. the

Embodiments of the present invention make the following improvements to the problems existing in the prior art:

The protection channel in the receiving direction of the A terminal fails, and the B terminal (the working channel has a switching request terminal) sends the same K byte as the protection channel on the request bridge working channel, requesting the A terminal to bridge, that is, sending the lower four bits of K1 to indicate the request bridge channel number ;

When the protection channel in the receiving direction of the A terminal fails, it can bridge the service carried by the specified working channel according to the K byte received on the working channel (that is, according to the received request bridge channel number indicated by the lower four bits of K1);

A then sends the bridging information of the local end to the B end through the sending direction protection channel, that is, the sent high four bits of K2 indicate the bridged channel number;

Terminal B receives the bridged information from the protection channel (that is, the bridged channel number indicated by the received high four bits of K2), selects services from the protection channel, and completes the single-ended switching;

When end B releases switching (that is, no longer selectively receives services from the protection channel), it restores the K-byte information on the working channel, and no longer sends the same K-byte information as the protection channel. the

Embodiment four:

Fig. 8 is a schematic diagram of four-fiber ring protection according to an embodiment of the present invention. In the four-fiber ring shown in Fig. 8, it is assumed that before the four SFs in #1<--->#2 sections do not appear, the # 3. If the eastbound FS-R command is issued, SF-1, SF-2, SF-3, and SF-4 will appear in sequence, and the state on the ring should change as follows theoretically:

(1) When there is only SF-1, there is only FS-R switching on the ring, and both #1 and #2 are in full pass-through state;

(2) When SF-2 appears again, the SF-R synthesized by heretical SF-P and SF-S should coexist with FS-R, at this time, #1 and #2 should establish SF-R switching;

(3) When SF-3 appears, the coexistence of SF-R and FS-R ring switching is still maintained;

(4) When SF-4 appears, both #1 and #2 can synthesize SF-R according to the local request, and SF-R and FS-R still coexist. the

However, based on the existing technology (regardless of RDI), the state on the ring cannot change according to the ideal situation:

(1) When there is only SF-1, there is only FS-R switching on the ring, #1 and #2 are both in the full pass-through state, and #3 and #4 are both established for FS-R switching;

(2) When SF-2 occurs again, #1 receives a FS-R K byte request on the long path that does not point to itself in the west direction, but fails to receive K bytes in the east direction due to failure of the protection channel, and #1 sends SF-R on the long and short paths. P K bytes, #1 enters the section switching state;

And #2 can enter the SF-R switching state according to the SF-1 detected locally and the SF-PK byte received on the short-path protection channel, and according to the FS-R long-path K received from the east that does not point to itself The byte calculation should be that SF-R and FS-R ring switching coexist, so there is an SF-R switching page on #2, and #2 sends a SF-R switching request on the long and short paths;

After #3 received the SF-R long-path K bytes sent by #2 in the west direction, it also calculated that FS-R and SF-R ring switching should coexist on the ring, and #3 also maintained the ring switching state, and according to the Its own SF-R long-path K bytes maintains FS-R switching pages;

#4 releases the FS-R switching page because it no longer receives FS-R long-path K bytes;

(3) When SF-3 appears, the state on the ring remains unchanged;

(4) When SF-4 appears, both #1 and #2 can synthesize SF-R according to the local request, and SF-R and FS-R coexist on the ring. the

Comparing the state transition under the existing technology with the state transition under the ideal situation, we can find that the states of (2) and (3) under the existing technology are incorrect, and it is necessary to improve the existing technology. Through the analysis, it can be seen that the reason why the switching state is wrong in the two cases of (2) and (3) is that #1 cannot get the switching request of #2 in the east direction, which leads to the incomplete calculation of information, thus, the present invention implements For example, the following improvement measures are proposed:

When the highest switching request of #2 is SF-R, send the same K bytes on the working channel as the protection channel, that is, send SF-R short path K bytes on the west direction;

#1 When the east protection channel fails and the working channel does not fail, it can enter or maintain the SF-R ring switching state according to the short-path K bytes received on the working channel;

When #2 detects that the working channel has returned to normal, it actively restores the K-byte information on the working channel, and no longer sends the same K-byte information as the protection channel. the

After the above improvements, in Figure 8, when SF-2 appears, both #1 and #2 can calculate that the SF-R and FS-R ring switching coexists, and when SF-3 and SF-4 appear, the ring Both will maintain the coexistence of ring switching, which is already in line with the ideal situation. the

Based on the above-mentioned embodiments, the technical solutions provided by the embodiments of the present invention can be described as follows:

1. Linear 1:N single-ended protection

Applicable conditions:

One end has a working channel switching request, and the corresponding working channel at the opposite end does not fail, and the receiving direction protection channel fails. the

Countermeasures:

There is a working channel switching request end to send the same K bytes as the protection channel on the current request bridge working channel;

The failure end of the protection channel in the receiving direction can perform bridging according to the K byte request received on the working channel, and indicate the number of the bridged channel in the sent K2 byte, and the switching initiator can establish a switchover based on the K byte received , so as to complete the protection of the business;

When the switching request end of a working channel releases switching, restore the K byte information on the corresponding working channel (that is, make the K byte sent now the same as the K byte sent in the normal situation, so as to restore the K byte in the normal situation. bytes), and no longer send the same K bytes with the protection channel (that is, no longer synchronized with the protection channel). the

The processing flow of the switching request end with a working channel is shown in Figure 9, and Figure 9 is a processing flow chart of the linear 1:N single-ended protection switching of the embodiment of the present invention, including the following steps:

When there is a switching request on the working channel, if the protection channel at the opposite end is not invalid, the switching request is only sent on the protection channel according to the existing technology;

If the protection channel in the receiving direction of the opposite end fails, not only the switching request is sent on the protection channel, but also the same switching request is sent on the working channel;

When the switching is released, the K-byte information of the working channel is restored, and the same K-byte information as that on the protection channel is no longer sent. the

The processing flow of the failure end of the protection channel in the receiving direction is shown in Figure 10, and Figure 10 is another processing flow chart of the linear 1:N single-ended protection switching of the embodiment of the present invention, including the following steps:

Under the condition that the protection channel in the receiving direction fails, when receiving the K-byte request on the working channel, if the upper four bits of K1 are legal and valid switching requests, the switching request will be responded to. the

2. Four-fiber shared protection ring

Applicable conditions:

There is SF or SD in the working channel at one end of a section;

In addition, the protection channel in the receiving direction of the opposite end in the same segment fails, but the working channel does not fail. the

Countermeasures:

The SF or SD end of the working channel sends the same K bytes as the protection channel on the request bridge working channel;

In the receiving direction, when the protection channel fails and the working channel does not fail, the K byte request is received from the working channel in this section;

When the working channel SF or SD end resumes the working channel, it will no longer synchronize with the protection channel in terms of sending K bytes, and restore the original K byte information (that is, what K bytes are usually sent, what K bytes are sent now) byte). the

The processing flow of the working channel SF or SD end is shown in Figure 11, and Figure 11 is a processing flow chart of the four-fiber shared protection ring switching in the embodiment of the present invention, including the following steps:

When the working channel has SF or SD, if the protection channel at the opposite end does not fail, then according to the existing technology, only the switching request is sent on the protection channel; if the protection channel fails in the receiving direction at the opposite end, the switching request is not only sent on the The same switching request is also sent on the channel; when the signal of the working channel is recovered, the K-byte information of the working channel is restored, and the same K-byte information as that on the protection channel is no longer sent. the

The processing flow of the failure end of the protection channel in the receiving direction is similar to that in the 1:N single-end, see FIG. 10 , and the description of the steps is omitted. the

It can be seen from the above description that the embodiment of the present invention uses the working channel to send K bytes to improve the multiplex section protection function, thereby solving the problem that the end of the protection channel failure in the receiving direction cannot effectively know the switching request of the opposite end. Therefore, the implementation of the present invention The beneficial effect brought by the example is that it can improve the multiplex section protection in the following situations:

(1) In the linear 1:N single-ended protection architecture, one end has a working channel switching request, and the receiving direction protection channel of the opposite end fails. In this case, the switching cannot be completed under the existing technology. After adopting the embodiment of the present invention, as long as the opposite end If the corresponding working channel does not fail, the switching can be completed, so as to better realize service protection;

(2) There is SF or SD in the working channel at one end of the same section of the four-fiber ring, and only the protection channel in the receiving direction fails at the opposite end. Under the existing technology, RDI (MS-RDI in SDH, RDI-L in SONET) can be used ) instruction to establish and maintain switching, due to the unreliability of RDI, it has certain defects. After adopting the embodiment of the present invention, the coexistence of ring switching can be better ensured, and all possible protected services can be protected as much as possible. the

Obviously, those skilled in the art should understand that each module or each step of the above-mentioned embodiments of the present invention can be implemented by a general-purpose computing device, and they can be concentrated on a single computing device, or distributed among multiple computing devices. Optionally, they can be implemented with executable program codes of computing devices, thus, they can be stored in storage devices and executed by computing devices, or they can be made into individual integrated circuit modules, or the Multiple modules or steps among them are realized by making a single integrated circuit module. As such, the present invention is not limited to any specific combination of hardware and software. It should be understood that changes in these specific implementations are obvious to those skilled in the art and do not depart from the spirit protection scope of the present invention. the

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention. the

Claims (10)

1. reverse method that is used for optical transport network; wherein; described optical transport network comprises side a and b; each other according to linear 1: the single-ended protection framework of N/4F Ring framework establishes protection passage and service aisle; when B holds to the protection channel failure of A end; and B holds when claimed, it is characterized in that, may further comprise the steps:

The B end sends the K byte information that comprises the bridge joint request by its service aisle to the A end;

After the A termination is received described K byte information, specify according to described bridge joint request

A holds to the protection passage of B end and service aisle while bearer service;

The A end sends bridge information by its protection passage to the B end;

The B end is according to after the described bridge information that receives, and is professional from protection passage choosing receipts, switches to finish.

2. reverse method according to claim 1 is characterized in that, this method also comprises:

When the B end was no longer claimed, the B end discharged described switching, and the B end sends the K byte information that does not comprise the bridge joint request by its service aisle to the A end;

The A end is removed and is specified A to hold to the protection passage bearer service of B end according to the described K byte information that does not comprise the bridge joint request that receives.

3. reverse method according to claim 1 is characterized in that, described K byte comprises K1 byte and K2 byte, and wherein, low four of K1 is used for indication request bridged appearances number, and high four of K2 is used to indicate bridged appearances number.

4. according to each described reverse method in the claim 1 to 3, it is characterized in that this method specifically comprises: make up upright protection passage and service aisle according to the single-ended fender bracket of linearity 1: N between the side a and b of described optical transport network; Wherein, B holds to the protection passage of A end and has Signal Fail, and A holds to the service aisle of B end and exists Signal Fail or Signal Degrade or B termination to receive that the outside switches order.

5. according to each described reverse method in the claim 1 to 3, it is characterized in that this method specifically comprises: set up protection passage and service aisle according to the 4F Ring framework between the side a and b of described optical transport network; Wherein, B holds the protection passage of holding to A to have Signal Fail, and A holds the service aisle of holding to B to have Signal Fail or Signal Degrade, and the B end is in Signal Fail ring switching attitude.

6. changeover apparatus that is used for optical transport network, wherein, described optical transport network comprises side a and b, each other according to linear 1: the single-ended protection framework of N/4F Ring framework establishes protection passage and service aisle, it is characterized in that, comprising:

Service aisle K byte sending module is used for holding protection channel failure to A end as B, and B holds when claimed, and instruction B end sends the K byte information that comprises the bridge joint request by its service aisle to the A end;

Professional designated module, be used to instruct the A termination to receive described K byte information after, specify A to hold protection passage and service aisle while bearer service according to described bridge joint request to the B end;

Responder module is used to instruct the A end to send bridge information by its protection passage to the B end; And

Switch module, be used to instruct the B end according to after the described bridge information that receives, professional from protection passage choosing receipts, switch to finish.

7. changeover apparatus according to claim 6 is characterized in that, also comprises:

Recover module; be used for instruction when the B end is no longer claimed; instruction B end discharges described switching; the B end sends the K byte information that does not comprise the bridge joint request by its service aisle to the A end; and instruction A end is removed and is specified A to hold to the protection passage bearer service of B end according to the described K byte information that does not comprise the bridge joint request that receives.

8. changeover apparatus according to claim 6 is characterized in that, described K byte comprises K1 byte and K2 byte, and wherein, low four of K1 is used for indication request bridged appearances number, and high four of K2 is used to indicate bridged appearances number.

9. according to each described changeover apparatus in the claim 6 to 8, it is characterized in that, make up upright protection passage and service aisle according to the single-ended fender bracket of linearity 1: N between the side a and b.

10. according to each described changeover apparatus in the claim 6 to 8, it is characterized in that, establish protection passage and service aisle according to the 4F Ring framework between the side a and b; Wherein, B holds the protection passage of holding to A to have Signal Fail, and A holds the service aisle of holding to B to have Signal Fail or Signal Degrade, and the B end is in Signal Fail ring switching attitude.

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