CN1319967A

CN1319967A - Method and device for providing facilities and module redundancy in telecommunication exchange equipment

Info

Publication number: CN1319967A
Application number: CN 00103776
Authority: CN
Inventors: S·K·维斯瓦纳坦; R·W·库巴格
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2000-03-09
Filing date: 2000-03-09
Publication date: 2001-10-31

Abstract

The present invention is characterized by that a crosspoint converter is used to select one from first steam of ATM informatino source and second stream of ATM information source, the first stream and second stream are identical, and further is used to make selection according to the error condition detected in first stream operation by working circuit and substitute the first stream with second stream. The working circuit mounted on the interface module is used for receiving first stream of ATM information source and operating it, and the protecting circuit mounted on the redundance interface module is used for receiving second information source stream and operating it. The protection circuit and working circuit and identical in function and mutual synchronous so as to can switch from one stream to other stream and do not interrupt network service.

Description

The method and apparatus of facility and module redundancy is provided in telecommunication exchange equipment

The present invention relates generally to communication network, more specifically, relate to and have module redundancy and connect ATM (asynchronous communication mode) equipment of fault to prevent network:

TAM (asynchronous communication mode) high speed switching network as a kind of can be with current digital service and new multimedia service, for example, video on demand, the multi-source live tv, the CD Quality music, the local area network (LAN) technology of high-speed data transfer interconnected and that be used for science and industry has put forward.For the service that realizes that these are different, the ATM net is designed to be treated to various real-time, as video conference and non real-time, and the miscellaneous transmission characteristic required as the application of browsing of Email and net, for example, constant speed, speed change are with burst.The basic principle of ATM net is known for those skilled in the art.In many published discussion (for example, referring to: Andrew S.Tanenbaum, Computer Networks, PrenticeHall, 1996,3rd ed.) that all have in reference to books and periodicals.

The data that ATM utilizes the cell exchange technology exchange to transmit.With little, fixedly the ATM cell of 53 byte longs of scale transmits all data in the ATM net between the transducer of net, and wherein 5 bytes are used for the head section, and 48 bytes are used for information or data load.The head section of each cell comprises the virtual connection identifier that is used for uploading at network the unit of delivering letters.Each ATM cell is included in two parts connection identifier (CID in the header section: virtual route identifier (VPI) and virtual circuit identifier (VCI).This two parts connection identifier (CID is identified in a virtual connection of the ATM on the physical interface uniquely.

ATM is a kind of connection-oriented technology.That is to say, require to call out to user B, be similar to call, between two users, connect by user A.In case access path is established, on identical access path, transmit all cell of data.This just guarantees that cell will send in order.Though ATM sets up circuit between two main frames, yet adopt cell exchange technology to set up sort circuit in inside.When a virtual circuit was set up between two main frames, what really take place was the charting of having set up the storage routing iinformation in each transducer on the path between the main frame.

It below is an example of the situation that when user A is connected to user B, taken place.At first, user A sends a call request to user B.Call request arrives an inlet transducer of atm network.The NNI signalling step that is positioned at call control software utilization and the NNI route service combination of inlet transducer locatees and sets up user A for user B to be connected the virtual of last swap data with user B.

Be established in case connect, data can exchange between user A and user B.In typical case, data flow is carried out as follows.The application program that user A opens on the user A computer sends data to user B.To receive data from the application program of user A at the network software of user A side, and with data placement in bag.Each grouping is arranged to the variable length sequence of one 53 byte ATM cell, carries by comprising the packets of information head section cell relevant with application program data load the preceding.Being grouped on the atm network cell connects a cell ground and sends to user B from user A.Cell is re-assemblied to dividing into groups and submitting to user B as an application packet by the software of user B end.

In order to guarantee service quality and to regulate service traffics and obstruction, atm network provides several mechanism.Traffic shaping has put forward for atm network with the Congestion Control of communicating by letter.In traffic shaping, the service quality contract has just formed before the transfer of data between user and network, has wherein stipulated desired transmission parameter.For example, the user can stipulate a kind of requirement, and promptly data 10 microseconds of delaying time transmit.Conversely, the user is required for example, to send the condition of abiding by contract below the speed of deciding through consultation.Communication control function, for example, customer parameter control (UPC) forces the user to meet clause in the contract in atm network.

The physical layer of atm network connects usually by forming by the optical fiber of SONET (Synchronous Optical Network) standard operation.The SONET system is by the transmission network parts, as adds/tap multiplexer (ADM), and multiplexer and transponder are formed, and are all connected by optical fiber.ATM transducer in sonet network can have one or more sonet interface cell boards that ATM cell is extracted out from the light signal of fiber path, make the ATM transducer can use ATM and handle and routing function.

In atm network, the reliability of ATM transducer is critical, because the fault that the atm device of malfunction can cause each constant virtual circuit (PVC) to be connected with the virtual circuit (SVC) that is exchanged.The malfunction of atm device is divided into two class faults usually: facility fault and equipment fault.The facility fault generally is summed up as the fault of any external object for equipment, for example is input to a cable fault in the cable of equipment, and fiber is cut off, perhaps or even the problem of connector.Someone may pull out the connector of equipment front, and this situation is classified as the facility fault.Equipment fault comprises the interior any fault (for example electronic failure) of electronic unit of the equipment of occurring in itself.

In order to keep the reliability of network, do not take the fault of above-mentioned facilities and equipment into account, provide for the protection of atm device or other communication exchange equipment and wish very much.

Summary of the invention

In order to overcome above-mentioned problem, the present invention includes for the operating circuit that receives first cell flow configuration and for receiving the protective circuit of second cell flow configuration.In typical case, cell is an ATM cell.Second stream with first-class be identical.Be identical and the phase mutually synchronization on protective circuit and the operating circuit function.The crosspoint transducer is configured to choose first-class and does further configuration so that select and first-class with the second stream replacement according to detected error condition in first operating circuit.

Error condition can be facility error condition (for example, the cable that does not connect) or equipment error condition.The equipment error condition is a kind of fault of occurring in device interior (for example, sonet framer, multiplexer, customer parameter control unit, a router, and other and operating circuit and the associated circuit of protective circuit).

In another aspect of this invention, operating circuit receives first-class from light signal, and protective circuit receives second stream from identical light signal.

In another aspect of this invention, operating circuit is implemented on first plate, and protective circuit is implemented on second plate, first plate and second plate be separate and have any different.

In another aspect of this invention, operating circuit comprises a plurality of to the first-class atm cell of carrying out atm feature of going up, and protective circuit comprises a plurality of identical atm cells of second stream being carried out identical atm feature.One in the atm cell can be multiplexer, sonet framer, router, customer parameter control unit and signalling unit.

In another aspect of this invention, it is a plurality of mouthful that first module has, and wherein one or more mouthfuls are accepted their stream as the input of operating circuit, and their stream is accepted in the input that remaining mouthful can be used as protective circuit.

In another aspect of this invention, second module comprises protective circuit, and have a plurality of mouthful, one of them mouthful as protective circuit input accept second stream, their stream is accepted in the input that remaining mouthful can be used as operating circuit.

In one side more of the present invention, the member of an ATM transducer has a plurality of input ports, a plurality of delivery outlets, and be configured to the ATM cell that the cell flow from one of input port receives is sent to any one delivery outlet.

In another aspect of this invention, the input port of ATM transducer member receives ATM cell from cell flow, or first-class or second stream, depends on the selection of crosspoint transducer.

In another aspect of this invention, the second crosspoint transducer is configured to receive ATM cell from one of delivery outlet of ATM transducer member, and guides ATM cell into the 3rd stream, and further ATM cell is guided into the 4th stream.

In another aspect of this invention, second operating circuit is configured to receive the 3rd cell flow from the second crosspoint transducer.And second protective circuit is configured to receive the 4th signal flow from the second crosspoint transducer, and the 3rd stream is identical with the 4th stream.Be identical and the phase mutually synchronization on second protective circuit and the second operating circuit function.

The accompanying drawing summary

Fig. 1 is a system diagram, and a kind of the utilization according to the exemplary ATM converter structure that the invention provides the crosspoint transducer that prevents fault is shown.

Fig. 2 is a kind of being used at the block diagram of importing the exemplary sonet interface unit of working on the atm cell stream.

Fig. 3 is a kind of being used at the block diagram of exporting the exemplary sonet interface unit of working on the atm cell stream.

Fig. 4 is the example system sketch of a kind of foundation ATM converter structure of the present invention.

Fig. 5 is an exemplary block diagram, with explaining the data flow of guiding into by according to crosspoint of the present invention transducer.

Fig. 6 is an exemplary block diagram, with explaining the signal flow of guiding into by according to crosspoint of the present invention transducer.

Detailed Description Of The Invention

Fig. 1 illustrates a kind of preferred embodiment that is used to protect ATM exchange member 118 to exempt the structure of the present invention 100 of facilities and equipment malfunctions.Yet, should be appreciated that other embodiment of the present invention can be used the translation building block beyond the ATM.The present invention is for each independent constant virtual circuit (PVC) of atm network and the protection of 50 milliseconds of magnitudes is provided by the virtual circuit (SVC) that exchanged.Briefly, in order to provide identical information to two separate modules, the method for being implemented is to adopt 1+1APS (protection exchange automatically).Under the situation of fault, protection module will move and provide service.By adopting the crosspoint transducer that protection module is moved for the transducer member.

Fig. 1 illustrates the structure 100 with four SONET (Synchronous Optical Network) interface modules (SIU) 112,114,122,124.Crosspoint

transducer

116 and 120 joins these four SIU modules to transducer member 118.In optimum implementation,

module

112 and 122 circuit as transmitter-receiver on identical circuit board, implementing, same,

redundant module

114 and 124 circuit as transmitter-receiver on identical circuit board, implementing.Yet Fig. 1 has described module 112,114 on function, 122 and 124, therefore, the present invention is not limited to module 112,114,122,124 and circuit board hardware between any specific correspondence.Like this, other configuration is possible.In addition, module 112,114,122 and 124 circuit is two-way.Although be described to be input to

module

112 and 114 in these data, flow through system and pass through

module

122 and 124 outputs, should be noted that data also can be input to

module

122 and 124 flowing in the other direction, flow through system and pass through

module

112 and 114 outputs.

Fig. 2 is illustrated in mouthful optimum implementation of the SIU module 112 of the stream 131a-d of 1-4 reception sonet frame.Redundant module 114 is similarly worked with module 112.In optimum implementation, stream 131a-d is made up of the SDNET frame.The load structure that sonet frame is made up of frame administration overhead information and a series of ATM cell.The synchronous SONET carrier wave of this utilization supports that the process of asynchronous ATM layer is well-known in telecommunication technique.

SONET goes frame device 133a-d that the ATM load is extracted out from the sonet frame of stream 131a-d.The load of extracting out from each sonet frame is an atm cell stream.

Only at mouth 0, SIU module 112 comprises AAL5 (ATM Adaptation Layer 5) the unit 131f that is received in the ATM signal of telecommunication (non-light) on the mouth 0 from atm network.AAL5 unit 131f carries out the function of signaling by setting up with the calling of cancelling for atm network.In embodiments of the invention, a signalling function unit for four oral affairs of each module is arranged.The SIU module in the future modification or change the unnecessary this configuration constraint that is subjected to.Multiplexer unit 135a will be from the ATM signal of AAL5 131f output and the atm cell stream combination of exporting from SFM 133a.

Multiplexer unit 135a-135d will be sent to parameter control (UPC) unit 137a-d from the data flow that SONET goes frame device (SFM unit) 133a-133d and AAL5 131f to receive, the atm cell stream that monitoring receives from unit 135a-135d is so that implement user's contract and well-known other control function in the atm network technology.

The ATM cell that router one 39a-d will be received by UPC unit 137a-137d from the input port 119 of transducer member 118 is sent to suitable delivery outlet 121 (see figure 1)s of transducer member 118.Each ATM cell has a stature section and a load that carries information bit.The head section of ATM cell indicates a virtual address, and router determines where ATM cell is delivered to thus.For example, an ATM cell that is input to ATM transducer member 118 will be delivered to one of transducer member delivery outlet 1-8 according to the head section.Router is put in the ATM cell internal code so that this cell is transmitted by transducer member 118.

Fig. 3 is illustrated in the SIU module 122 that the atm cell stream 141a-d that receives from crosspoint transducer 120 delivery outlet 1-4 (is working hole at standing situation end opening 1-4) works.Router one 43a-143d can executable operations deliver to external network so that prepare with them on atm cell stream 141a-d.UPC unit 145a-145d can be in the shaping of executive communication amount or other operation from the cell flow of router one 43a-143d output.Multiplexer 147a-147d transmits data from UPC unit 145a-145d.In mouth 0, contrary multiplexer 147a is separated to signalling unit 142 with the call signal data from the ATM data flow.SFM module 149a-149d sets up the sonet frame be used to transmit the ATM cell that receives from MUX147a-147d.In addition, should be noted that,

module

122 and 124 is two-way, therefore when ATM signal flow 151a-151d be when mouth 1-4 receives, module 122,124 router unit (RT) 143a-143d, UPC145a-145d, MUX147a-147d, SFM149a-149d, carrying out above with AAL5 unit 142 is the identical functions of each unit description of module 112,114.

SIU module 114 is redundant modules that have with the SIU112 same circuits.Equally, SIU module 124 is redundant modules that comprise with SIU module 122 same

circuits.Interface module

112 and 122 is designated as action

module.Interface module

114 and 124 is designated as spare module.On any given time, one can be configured to or working hole or protection mouth in the module.When a protection mouthful maintenance was failure to actuate, working hole was working and is handling the input data.For clear this point, to give an example, the mouth 1 of SIU module 112 or the mouth 1 of module 114 will be working holes, other mouth will be the protection mouth.Similarly, the mouth 2 of SIU module 112 can be a working hole, and the mouth 2 of SIU module 114 is protection mouths, perhaps conversely.In this exemplary embodiment, all mouths of the SIU module 112 of action are chosen as working hole at the beginning, and all mouths of SIU module 114 are protection mouths.Refer again to Fig. 1, translation building block 118 can any one be sent to any one (8 mouths shown in Figure 1 for simplicity) in 8 delivery outlets 121 from 8 input ports 119 with all ATM cell.Usually, the ATM transducer can have the input (N) of any amount, that is to say, and can be N * Metzler matrix.Best, 16 input and output mouths are arranged.

Two crosspoint transducers 116,120 are arranged, the crosspoint transducer 120 on crosspoint transducer 116 on the transducer member input stage and transducer member 118 output stages.Crosspoint transducer 116 with input port and delivery outlet is connected in the delivery outlet 117 any with in its input port 136 any.Crosspoint transducer 120 is linked in the delivery outlet 141 any with in its input port 123 any.

Fig. 4 makes it more detailed than Fig. 1 with explaining basic structure 100 of the present invention by comprising the SIU modular circuit shown in Fig. 2 and 3.

Fig. 5 is with explaining according to the crosspoint transducer 116 of exemplary embodiment of the present invention and 120 data flow operations.In this specific configuration, the mouth 1 of

SIU module

112 and 2 and the mouth of redundant SIU module 114 3 are current working holes.Mouth 4 is not used in this example.In fact, mouth 4 both can be SIU122 and also can be SIU124 work in non-protected mode.

Present data flow with key-drawing 5.At first, remove frame device 133a at the mouth 1 atm cell stream 131a that receives of SIU module 112 by SONET, MUX135a, UPC unit 137a and router one 39a handle and export as atm cell stream 136a.Crosspoint transducer 116 201 is guided to delivery outlet 1 with atm cell stream 136a from the input port 1 of crosspoint transducer 116 along the path, makes cell flow link the mouth 1 of transducer member 118 and received by it.

Atm cell stream 131b is received and removes frame device 133b by SONET at the mouth 2 of SIU module 112, MUX135b, and UPC unit 137b and router one 39b handle, and export as atm cell stream 136b.Crosspoint transducer 116 207 is guided to delivery outlet 2 with atm cell stream 136b from its input port 2 along the path, makes cell flow link the mouth 2 of transducer member 118 and received by it.

The mouth 3 atm cell stream 131c that receive in SIU module 114 remove frame device 133c by SONET, and MUX135c, UPC unit 137c and router one 39c handle and export as atm cell stream 136c.Crosspoint transducer 116 213 is guided to delivery outlet 3 with atm cell stream 136c from the input port 7 of crosspoint transducer 116 along the path, makes cell flow link the input port 3 of transducer member 118 and received by it.Therefore, crosspoint transducer 116 is linked redundant module 114 delivery outlets 7 input port 3 of transducer member 118 to substitute standing path, and this path is mouth 3 input ports 3 of linking transducer member 118 with SIU module 112 when working.

Atm cell stream 131a also is provided for the input port 1 of SIU module 114.If in mouth 1 path of SIU112 equipment fault is arranged, communication can be switched so, is handled and is sent to the input port 1 of transducer member 118 and does not cancel calling by crosspoint transducer 116 by the mouth 1 of SIU module 114.In fact call out in the flyer mode and rebulid interruption concerning the user.This is a kind of progress aspect the atm network switching, does not cancel communication or calling because of crosspoint transducer treatment facility fault.

In essence; exemplary embodiment of the present invention can the checkout equipment fault; pass through then the ATM cell data are thrown off from out of order work SIU as the fault in SIU module (operating circuit); utilize the crosspoint to work and protect SIU to be connected to the transducer member, the ATM cell data are reselected route from the input (protective circuit) of another one SIU module.The crosspoint transducer makes the cell data of reselecting route turn back to its original path by the transducer member.User's lost-call not during equipment fault.Therefore, set up a kind of more reliable ATM switching network.

Transducer member 118 is sent to delivery outlet 121 according to the ATM cell that route instruction will receive in its input port 119.Predetermined be sent to the ATM cell of the delivery outlet 1 of transducer member 118,203 guide to the input port 1 of SIU122 and 205 delivery outlets 5 of guiding to mouthful 1 the crosspoint transducer 120 of direct connection SIU124 along the path simultaneously by crosspoint transducer 120 along the path by the ATM cell that ATM transducer 118 is sent among the cell flow 141a that the ATM cell of delivery outlet 1 forms from ATM cell 141a.As a result, identical ATM flows the mouth 1 that is sent to

SIU module

122 and 124 by crosspoint transducer 120 on path 203 and 205, thereby this just provides redundant path to be used to support 1 to add 1 (1+1) sonet protection exchange.

The predetermined delivery outlet 2 that is sent to transducer member 118 from atm cell stream 141b of ATM cell.209 guide to the mouth 2 of SIU122 and simultaneously along path 211 delivery outlets 6 of crosspoint transducer 120 of guiding to the mouth 2 of direct connection SIU124 by crosspoint transducer 120 along the path by the ATM cell that ATM transducer 118 is sent among the cell flow 141b that the ATM cell of delivery outlet 2 forms.The predetermined delivery outlet 3 that is sent to transducer member 118 from atm cell stream 141c of ATM cell.Then by ATM transducer 118 be sent among the cell flow 141c that the ATM cell of delivery outlet 3 forms ATM cell by crosspoint transducer 120 along the path 215 mouths 3 of guiding to SIU122,217 mouths 7 of guiding to the crosspoint transducer 120 of the mouth 3 of directly linking SIU124 simultaneously along the path.

Fig. 6 shows the example of the signal data stream that occurs during the call setup in a kind of exemplary embodiment of the present invention.In this specific configuration, the mouth 1 of

SIU module

112 and 2 and the mouth of redundant SIU module 114 3 are current action mouths.Notice that mouth 4 is not used in this example.

By SFM133a, MUX135a, UPC137a and RT139a handle and export as atm cell stream 136a at the mouth 1 atm cell stream 131a that receives of SIU module 112.Crosspoint transducer 116 along the path 301 with atm cell stream 136a from its mouthful 1 to mouth 1 so that cell flow be connected to the mouth 1 of transducer member 118 and receive by it.

By SFM133b, MUX135b, UPC137b and RT139b handle and export as atm cell stream 136b at the mouth 2 atm cell stream 131b that receive of SIU module 112.Crosspoint transducer 116 along the path 303 with atm cell stream 136b from its mouthful 2 to mouth 2 so that cell flow be connected to the mouth 2 of transducer member 118 and receive by it.

The atm cell stream 131c that receives in the input port 3 of SIU module 114 is by SFM133c, and MUX135c, UPC137c and RT139c handle and export as atm cell stream 136c.Crosspoint transducer 116 305 is guided to delivery outlet 3 with atm cell stream 136c from its input port 7 so that cell flow is connected to the input port 3 of transducer member 118 and is received by it along the path.

Transducer member 118 with ATM signal cell from the path 301,303,305 delivery outlets 1 that are sent to along path 307,309 and 311 on the transducer member 118.Thereby the call setup information of all

mouthfuls

1,2 and 3 is sent to mouth 1 along the path 312 to the signal element AAL5142 that handles the SIU module of calling out.Note, might cause the fault of AAL5142 on the SIU module 122 in order to use AAL5142 on the SIU module 124.

Though have only some embodiment to be described in the accompanying drawings in the equipment of the present invention and detailed description in front in be described, should be appreciated that the present invention is not limited to disclosed embodiment, other rearranging can be arranged, revise and replace, and do not depart from the spirit of the present invention that proposes and stipulate by following claim.Therefore, should be appreciated that scope of the present invention comprises all more such arrangements and only limited by following claim.

Claims

1. one kind provides the equipment and facilities redundant devices, comprising:

Be configured to receive the operating circuit of first communication data stream;

Be configured to receive the protective circuit of second communication data flow, second stream with first-class be identical, be identical also phase mutually synchronization on protective circuit and the operating circuit function; With

The crosspoint transducer is configured to select one and be configured to select and be alternative first-class with second stream according to detected error condition at least one operating circuit and first communication data stream from first-class and second stream.

2. device as claimed in claim 1, wherein communication data is the ATM cell data.

3. device as claimed in claim 1, wherein operating circuit is first-class from the light signal reception, and protective circuit receives second stream from light signal.

4. device as claimed in claim 1, wherein operating circuit is implemented on first circuit board, protective circuit is implemented on second circuit board, first circuit board and second circuit board be separate and difference arranged.

5. device as claimed in claim 1, wherein operating circuit comprises a plurality of ATM channels of carrying out atm feature on first-class, protective circuit comprises a plurality of the 2nd ATM channels of carrying out atm feature on second stream.

6. device as claimed in claim 5, wherein in the ATM channel and the 2nd ATM channel each all comprise a multiplexer.

7. device as claimed in claim 5, wherein in the ATM channel and the 2nd ATM channel comprises a sonet framer.

8. device as claimed in claim 5, wherein in the ATM channel and the 2nd ATM channel comprises a router.

9. device as claimed in claim 5, wherein in the ATM channel and the 2nd ATM channel comprises a customer parameter control unit.

10. device as claimed in claim 1 also comprises:

First module comprises operating circuit and has a plurality of mouthfuls that one of them mouthful accepted first-class as the input of operating circuit.

11. device as claimed in claim 1 also comprises:

Second module comprises protective circuit and has a plurality of mouthfuls that one of them mouthful accepted second stream as the input of protective circuit.

12. device as claimed in claim 1 also comprises:

ATM transducer member, have a plurality of input ports, a plurality of delivery outlets, and be configured to any one that be sent in described a plurality of delivery outlet of ATM cell from described a plurality of input ports, described ATM cell receives from described operating circuit as described first part.

13. device as claimed in claim 1 also comprises:

ATM transducer member; have a plurality of input ports; a plurality of delivery outlets, and be configured to any one that be sent in described a plurality of delivery outlet of ATM cell from described a plurality of input ports, described ATM cell receives from described protective circuit as the part of described second stream.

14. the device as claim 12 also comprises:

The second crosspoint transducer is configured to from a plurality of delivery outlets of ATM transducer member one and receives ATM cell and the ATM cell that receives is guided in the output of the output of second operating circuit and second protective circuit one.

15. device as claimed in claim 1, wherein error condition is the facility error condition.

16. as the device of claim 15, wherein the facility error condition comprises the cable of disconnection.

17. device as claimed in claim 1, wherein error condition is the equipment error condition.

18. as the device of claim 17, wherein the equipment error condition comprises the sonet framer fault, multiplexer fault, at least a fault in parameter control unit fault and the router failure.

19. the ATM circuit for the realization atm feature provides the method for equipment and facilities redundancy, comprising:

With first circuit first atm cell stream is carried out one group of atm feature and produce handled first-class;

With second circuit second atm cell stream is carried out atm feature and produce second stream of handling, second flows with first-class identical, and first circuit and second circuit realization atm feature, first circuit and second circuit be mutually synchronization mutually; With

According to detected error condition in first circuit; second stream of handling is substituted first stream of handling of specifying mouth that is input to the ATM transducer; first stream of handling is selected as the appointment mouth that is input to the ATM transducer at the beginning, provides redundancy protecting for atm feature thus.

20. as the method for claim 19, wherein atm feature comprises multipath conversion, the SONET framing is selected at least one function in the control of route and customer parameter.

21. one kind for ATM circuit provides the method for equipment and facilities redundancy, may further comprise the steps:

Receive first atm cell stream;

Form second atm cell stream identical with first atm cell stream;

Detect and first-class relevant error condition; With

According to detected error condition with first-class switch to second stream.

22. one kind for ATM circuit provides the method for equipment and facilities redundancy, may further comprise the steps:

Utilize the crosspoint transducer to duplicate ATM cell; With

Utilize the crosspoint transducer that redundant cell is sent to two different paths.