JPH07273797A - Optical packet switching device - Google Patents

Abstract

PURPOSE:To transmit a packet signal for maintenance by providing a means monitoring the packet signal for maintenance, outputting it in the case where the collection is not necessary, and providing a collecting means in the case where it is necessary. CONSTITUTION:After a cell signal for maintenance consisting of optical cell signals is converted into an electric cell signal by an optical/electric coversion part 110, a cell collection part 106 for maintenance judges whether or not a cell signal for maintenance is the one to be collected by a cell monitoring part 111 for maintenance. In this case, when the cell signal for maintenance is inserted by an optical ATM switching device, it is not collected and the cell signal for maintenance is outputted to an electric/optical conversion part 112. When it is judged to be a cell signal for maintenance to be collected, it is analyzed by a cell analysis part 113 for maintenance to have the maintenance information and it is given to a maintenance operation monitoring control part 121. Thus, even when a switching device 100 converts an optical packet signal, the packet signal for maintenance can be collected from the network, improving the maintenance and operation functions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical packet switching device, and more particularly to a method of inserting and recovering a maintenance packet signal.

[0002]

2. Description of the Related Art In recent years, a high-speed packet switching system called ATM (asynchronous transfer mode) switching, which has been put into practical use, uses an electronic ATM switch (a kind of packet switching device) using electronic logic. ing. In order to further increase the speed of this ATM switch, development and research of an ATM switch for exchanging cell signals (packets are called cells in the case of ATM switch) consisting of optical signals between both switches are in progress ( See, for example, Documents 1 and 2.

Reference 1 “Yasushi Takahashi, Taizo Kinoshita, Koji Ishida, Eiichi Amada,“ Experiment of HDTV Signal Exchange by Optical ATM Switch ”, Optical Switching Technology Study Group, PST91-24, pp33
-37, July 9, 1991] Reference 2 “H.Kobriski, E. Arthurs, RMBulley, JMCo.
oper, ELGoldstein, MSGoodman and MPVecch
i, ”An optoelectronic packet switch utilizing fas
t wavelength tuning ”, CH2535-3 / 88 / 0000-0948 1.0
0 c 1988 IEEE, pp29.5.1-29.5.6 ”The operation of an example of a conventional optical ATM switch (see Reference 1) will be briefly described. In the following description, a cell signal formed of an optical signal will be referred to as an optical cell signal when necessary, and a cell signal formed of an electric signal will be referred to as an electric cell signal as necessary.

In an optical ATM switch, an optical cell signal input from an input end sent through an optical fiber is
After being converted into an electric cell signal by the optical / electrical conversion unit,
The destination in the header of the cell signal is analyzed by the header processing unit, a new header is added, transferred to the buffer unit, and temporarily stored. An electric cell signal is read from the buffer section at a timing at which cell signals from a plurality of input terminals to the same output path do not collide in the optical switch described later, and the electric cell signal is read by the electric / optical conversion section. After being converted into a cell signal, it is input to the optical switch that is switching the route according to the above analysis result, guided to the designated output route, and output to the next ATM switch or terminal device side. Sent out.

This optical ATM switch is capable of operating at high speed and low power consumption as compared with the case of performing electrical processing because it switches cell signals which are optical signals.

In the above-mentioned conventional optical ATM switch, the switching means for guiding the optical cell signal to the output path is an optical switch, but as the switching means for guiding the optical cell signal to the output path,
An optical ATM switch to which a structure using a star coupler is applied has already been proposed.

[0007]

However, all of the conventional optical ATM exchanges have been put into the research and development of the basic optical exchange configuration, probably because the maintenance cell signal is inserted into the network. The method and recovery method were not disclosed, and the method was unknown.

Incidentally, as shown in FIG. 2, in a general ATM exchange in which a switching means for guiding a cell signal to an outgoing route handles a cell signal which is an electric signal, as shown in FIG. It is designed to be transmitted between two.

In the upstream ATM exchange 1, the maintenance cell inserting section 10 generates a maintenance cell signal at a certain time interval and inserts it into the input side transmission system of the switch 11, whereby another ATM exchange ( The maintenance cell signal reaches the downstream ATM exchange 2), and in the ATM exchange 2, the maintenance cell recovery unit 20 recovers the maintenance cell signal after the switch 21 is switched.

Therefore, the downstream ATM switch 2 is connected to the upstream ATM.
While the cell signal from the exchange 1 can be received, it can be determined that the line is alive. Also,
If the maintenance cell signal does not arrive forever, it can be determined that some failure has occurred in the line. Further, by writing the transmission time information (time stamp) in the data portion of the maintenance cell signal, the downstream AT
The M switch 2 can know the transmission delay time until arrival and its variation, and can check the line quality.

As described above, the conventional electric ATM
In the exchange, by transmitting the maintenance cell signal, it is possible to check the operation status such as whether the network is operating normally, and the maintenance cell signal transmission is very significant.

However, in the conventional optical ATM switch, unlike the electric type ATM switch, no method for inserting or recovering the maintenance cell signal into the network is proposed, so that it is determined whether the network is normal or abnormal. Therefore, it is desired to provide the optical ATM switch with a configuration for inserting the maintenance cell signal into the transmission system and a configuration for collecting the maintenance cell signal from the transmission system. Of course, there are many differences between the conventional electric ATM switch and the optical ATM switch, including the switching means, and the transmission configuration of the maintenance cell signal in the electric ATM switch is as follows.
There is no relationship applicable to the transmission configuration of the maintenance cell signal in the optical ATM switch.

Such a problem similarly occurs not only in the optical packet switching apparatus for the ATM switching network (optical ATM switching apparatus) but also in the optical packet switching apparatus for other packet switching networks.

[0014]

In order to solve such a problem, in the first aspect of the present invention, an optical packet switching apparatus in which a switching means for guiding an input packet signal to an outgoing route handles a packet signal which is an optical signal. In the above, the following means are provided.

That is, it is necessary to collect the packet signal based on the optical / electrical converting means for converting the packet signal composed of the optical signal after the exchange processing by the exchanging means into the electric signal and the packet signal converted into the electric signal. Maintenance packet monitor that determines whether the packet signal is a proper maintenance packet signal, outputs the packet signal from the optical packet switching device when collection is unnecessary, and collects the packet signal when collection is necessary. And means.

In the second aspect of the present invention, the switching means guides the packet signal input to the output route according to the information obtained by analyzing the packet signal input by the header processing means. In the optical packet switching device in which the switching means handles the packet signal of the optical signal, the following means are provided.

That is, depending on the result of analysis by the header processing means, a certain optical attribute (for example, wavelength or polarization) is determined depending on whether the input packet signal is a maintenance packet signal that needs to be collected or other packet signals. Optical attribute variable means provided in the preceding stage of the switching means or as an internal configuration for making packet signals of optical signals different in wave state) and packet collection for maintenance that collects packet signals made up of optical signals when given Means and the packet signal of the optical signal output from the switching means according to the content of the optical attribute of the packet signal, and when the attribute content relates to a packet signal that does not need to be recovered, the packet signal Is output from the optical packet switching device, and the packet signal is maintained when the attribute content is related to the packet signal that needs to be collected. It provided an optical attribute discriminating means for providing the packet recovery unit.

Further, in the third aspect of the present invention, the switching means guides the packet signal input to the output route according to the information obtained by analyzing the packet signal input by the header processing means, In the optical packet switching device in which the switching means handles the packet signal of the optical signal, the maintenance packet inserting means for inserting the maintenance packet signal into the network is provided with the header processing means as an entrance.

[0019]

In the first and second aspects of the present invention, the optical packet switching apparatus has a maintenance packet signal collecting structure.

In the first aspect of the present invention, the optical / electrical converting means converts the packet signal, which is an optical signal after the exchange processing, into an electric signal, and the maintenance packet monitoring is performed based on the packet signal converted into the electric signal. Means determines whether or not the packet signal is a maintenance packet signal that needs to be collected, outputs the packet signal from the optical packet switching device when collection is unnecessary, and when the collection is necessary, Collect the packet signal. As described above, the maintenance packet signal can be recovered even if the exchange process is performed with the packet signal of the optical signal.

In the second aspect of the present invention, the optical attribute changing means determines whether the input packet signal is a maintenance packet signal which needs to be collected or not depending on the analysis result by the header processing means. In some cases, a packet signal of an optical signal having a certain optical attribute (for example, wavelength or polarization state) is different, and the optical attribute discriminating means outputs the packet signal of the optical signal output from the switching means as an optical signal included in the packet signal. Discriminate according to the content of the attribute, and if the attribute content relates to a packet signal that does not need to be collected, the packet signal is output from the optical packet switching device, and the attribute content relates to the packet signal that needs to be collected. When the packet is a packet, the packet signal is given to the maintenance packet collecting means to be collected. Therefore, the optical / electrical conversion is not required for the recovery, the configuration is simplified, and the packet signals other than the maintenance packet signal do not have to pass through the maintenance packet recovery means, so that the transmission delay time can be shortened. .

The structure of the recovery side has been described above.
Needless to say, an optical packet switching device having a maintenance packet signal insertion structure is also required. A third aspect of the present invention is an optical packet switching apparatus having a maintenance packet signal recovery configuration.

A third aspect of the present invention is a header processing means capable of grasping a general packet signal transmission state so that a maintenance packet signal can be inserted into a network without affecting a packet signal already transmitted through the network. The maintenance packet insertion means inserts the maintenance packet signal into the network with the entry point at. Further, when such a portion is used as the insertion portion, the maintenance packet signal always passes through the buffer unit for contention adjustment, which has the greatest influence on the transmission delay time, so that the transmission delay information having high utility value can be obtained.

[0024]

【Example】

(A) First Embodiment A first embodiment in which the optical packet switch according to the present invention is applied to an optical ATM switch for an ATM network will be described below in detail with reference to the drawings.

FIG. 1 shows the optical ATM of the first embodiment.
FIG. 3 is a block diagram showing a configuration of the exchange 100, and FIG. 3 shows a format of a maintenance cell signal.

Note that FIG. 1 shows a case in which there are four incoming routes and four outgoing routes for simplification of the drawing. In the following description, the same constituent element provided for each incoming or outgoing route is given the same three-digit code (only this is shown in FIG. 1), and when distinction is required , "-1", "-2", "-3", and "-4" are given after that. The same applies to the description of other embodiments described later.

In FIG. 1, this optical ATM switch 100 is shown.
Is an optical / electrical conversion unit 101, a header processing unit 102, a buffer unit 103, from the input end IN to the output end OUT.
An electric / optical conversion unit 104, an optical switch 105, and a maintenance cell collection unit 106 are sequentially provided. Here, the optical / electrical conversion unit 101, the header processing unit 102, and the buffer unit 10
3, electric / optical conversion unit 104 and maintenance cell recovery unit 106
Is provided for each route, and the optical switch 105 is commonly provided for each route. In addition to the configuration related to the general cell signal transmission processing as described above, the maintenance operation monitoring control unit 121 and the maintenance cell insertion unit 12 related to the maintenance operation.
0 is provided. The maintenance cell collection unit 106
Is also a configuration related to a general cell signal transmission process,
It is also a configuration related to the maintenance operation.

An optical cell signal sent through an optical fiber (not shown) has an input end IN- corresponding to its source.
, ..., IN-4 are input to the optical ATM switch 100. The optical cell signals input in this way are converted into optical / electrical conversion units 1 corresponding to the input terminals IN-1, ..., IN-4.
01-1, ..., 101-4.

Each optical / electrical conversion unit 101-1, ..., 101
-4 respectively convert the incoming optical cell signals into electric cell signals and correspond to the corresponding header processing units 102-1, ..., 102.
Give to -4.

Each header processing unit 102-1, ..., 102-
4 analyzes the destination existing in the header of the input cell signal, adds a new header for directing the destination to the next communication node of the optical ATM switch 100, and corresponds to the corresponding buffer unit 103-1. , 103-4. Note that each header processing unit 102-1 in FIG.
, 102-4 are buffer units 103-1, ..., 103
-4, both access control configurations (write configuration and read configuration) are included. In addition, each header processing unit 10
2-1, ..., 102-4 respectively give the analysis result to the optical switch 105 so that the optical switch 105 switches the route according to the analysis result.

Further, each header processing unit 102-1, ...,
Reference numeral 102-4 functions as an entrance for inserting a maintenance cell signal OAM as shown in FIG. 3 formed by a maintenance cell insertion unit 120 described later into a transmission route (network).

FIG. 3 shows an example of the maintenance cell signal. The maintenance cell signal OAM in this example includes a 5-byte header portion and a 53-byte data portion.
A bit pattern indicating that this cell signal is a maintenance cell signal OAM transmitted between adjacent optical ATM exchanges (100) in the 4 bytes on the head side of the header part (arbitrary bits also exist in 4 bytes). ) Has been inserted. on the other hand,
The maintenance cell signal OAM is stored in the data section by the maintenance cell inserting section 120 and any of the header processing sections 102.
, ..., 102-4, time information (time stamp) to be inserted into the transmission route (network) is inserted. Further, in the header portion or the data portion, the identification information of the optical ATM switch 100 which is the transmission source in which the maintenance cell signal OAM is inserted in the transmission route is also inserted.

As the maintenance cell signal, a maintenance cell signal transmitted between adjacent optical ATM switches (100) and a maintenance cell signal transmitted between terminal devices (end-to-end) are used. Although there are types, the present invention relates to the former maintenance cell signal OAM.

Each buffer unit (FIFO memory) 103-
, 103-4 respectively temporarily store the cell signals from the corresponding header processing units 102-1, ..., 102-4, and as will be described later, a conflict occurs in the output route from the optical switch 105. At a timing such that there is no such, the accumulated cell signals are converted into corresponding electric / optical conversion units 104-1, ..., 1
It outputs to 04-4.

Each of the electric / optical converters 104-1, ..., 104
-4 is the corresponding buffer unit 103-1, ..., 103-
The electric cell signal from the No. 4 is converted into an optical cell signal and input to the optical switch 105. In the case of the first embodiment, each electric / optical conversion unit 104-1, ..., 104-4
The wavelength of the optical cell signal from is arbitrary. A laser diode, for example, can be applied to the electric / optical conversion units 104-1, ..., 104-4.

The optical switch 105 is for switching between four incoming routes and four outgoing routes. The optical switch 105 here has a built-in contention control unit and switches between the ingress route and the egress route according to the header analysis result from each header processing unit 102-1, ..., 102-4. At the same time, if any conflict with the outgoing route is likely to occur, one of the cell signals is prioritized. That is, the priority cell signal is transferred to the buffer unit 103- via the header processing unit 102-i related to the cell signal.
i is read and driven to be input to the optical switch 105,
The non-priority cell signal is continuously stored in the buffer unit 103-j. The optical cell signal output from the optical switch 105 is input to each maintenance cell recovery unit 106-1, ..., 106-4 inserted in each path.

The optical switch (excluding the contention controller) 105 may be a waveguide optical switch or an optical transistor array.

Each maintenance cell collection unit 106-1, ..., 10
Reference numerals 6-4 denote optical / electrical conversion units 110-1, ..., 1 respectively.
10-4, maintenance cell monitoring unit 111-1, ..., 111-
, 112-4 and electrical / optical conversion units 112-1, ..., 112-4 and maintenance cell analysis units 113-1, ..., 113-4.

Each optical / electrical converter 110-1, ..., 110
-4 respectively converts the optical cell signal coming from the optical switch 105 into an electric cell signal and corresponds to the monitoring unit 111-
1, ..., 111-4.

Each of the maintenance cell monitoring units 111-1, ..., 11
1-4 respectively monitor whether the input cell signal is a maintenance cell signal to be collected, and if it is a maintenance cell signal to be collected, the corresponding maintenance cell analysis unit 113-1,
, 113-4, and on the other hand, the electrical / optical conversion units 112-1, ..., 11 corresponding to the cell signals that are not the recovery target.
Give to 2-4. That is, only the maintenance cell signal in which the bit pattern defining the maintenance cell signal as shown in FIG. 3 is inserted in the header, and the exchange identification information of the transmission source is not that of the optical ATM exchange 100. , Corresponding maintenance cell analysis units 113-1, ..., 11
3-4, and the other cell signals are provided to the corresponding electric / optical conversion units 112-1, ..., 112-4.
Therefore, although there is a maintenance cell signal in the cell signals that are not recovered, the maintenance cell signal is inserted by the optical ATM switch 100 as a transmission source, and is difficult to be recovered.

Each of the electric / optical conversion units 112-1, ..., 112
-4 is the corresponding maintenance cell monitoring unit 111-
, ..., 111-4 are converted into optical cell signals and output from output terminals OUT-1, ..., OUT-4 to an optical fiber (not shown). Each of the electrical / optical converters 112-1, ..., 124-4 converts into an optical cell signal having a predetermined wavelength, for example.

Each of the maintenance cell analysis units 113-1, ..., 11
3-4 respectively analyze the received maintenance cell signal,
Maintenance operation monitoring control unit 1
Give to 21. For example, the time stamp inserted in the maintenance cell signal is compared with the reception time, and a certain optical A
The transmission delay time from the TM exchange to the optical ATM exchange 100 is obtained, and the transmission delay time, the average value of the transmission delay times, and / or the change tendency of the transmission delay times are given to the maintenance operation unit 121. Further, for example, the fact that the maintenance cell signal is not continuously received for a long period of time is given to the maintenance operation monitoring control unit 121.

The maintenance operation monitoring control unit 121 stores the information given from the maintenance cell analysis units 113-1 to 113-4,
Useful for network maintenance and operation. In addition, the maintenance operation monitoring control unit 121 appropriately controls activation of the maintenance cell insertion unit 120.

Under the control of the maintenance operation monitoring control unit 121, the maintenance cell inserting unit 120 controls each header processing unit 102-1.
, 102-4, the maintenance cell signal having the current time information (time stamp) shown in FIG. 3 is inserted into the transmission route (network) every predetermined time (for example, 1 second). The maintenance cell insertion unit 120 inserts the maintenance cell signal into the path to be inserted at a timing when there is no general cell signal. Therefore, strictly speaking, the insertion period is not constant at the predetermined time, and the time stamp is also changed accordingly.

Optical ATM switch 1 comprising the above-mentioned respective parts
At 00, an ordinary optical cell signal from an optical ATM switch (or terminal device) on the upstream side (not shown) is, for example, input terminal I.
It is assumed that the data is input to N-2.

This optical cell signal is transferred to the optical / electrical converter 101.
-2, the destination in the header of the cell signal is analyzed by the header processing unit 102-2, a new header is added, and the buffer unit 103 is added.
-2 and is temporarily stored. This buffer unit 10
From 3-2, an electric cell signal is read out at a timing when cell signals from a plurality of input terminals do not compete in the optical switch 105, and the electric cell signal is read out.
After being converted into an optical cell signal in 4-2, it is input to the optical switch 105 that is switching the route according to the above-mentioned analysis result, and the maintenance cell is inserted in the designated output route. It is input to the section (here, 106-1).

In the maintenance cell collecting section 106-1,
This optical cell signal is converted into an electric cell signal by the optical / electrical conversion unit 110-1, and then the maintenance cell monitoring unit 111 is used.
-1 determines whether the maintenance cell signal should be recovered. Since this cell signal is not a maintenance cell signal to be collected, it is given from the maintenance cell monitoring section 111-1 to the electrical / optical conversion section 112-1 and output.

Next, the maintenance cell signal (optical cell signal) sent by the upstream optical ATM switch (not shown) is the first cell signal.
For example, the input end IN-1 of the optical ATM switch 100 of the embodiment.
Suppose that it is input to.

This optical cell signal is transferred to the optical / electrical converter 101.
After being converted into an electric cell signal by -1, the header of the cell signal is analyzed by the header processing unit 102-1 and after the reception cell signal is recognized as a maintenance cell signal, the buffer unit 103- 1, and is temporarily stored. A maintenance cell signal is read from the buffer unit 103-1 at a timing at which cell signals from a plurality of input terminals do not conflict with each other in the optical switch 105, and the maintenance air cell signal is read by the electrical / optical conversion unit 104-1. After being converted into an optical cell signal, it is input to the optical switch 105. In the first embodiment, for example, when a maintenance cell signal is received, it is switched by the optical switch 105 in the same manner as the immediately preceding cell signal from the incoming route. It is input to the maintenance cell collection unit (here, 106-3) inserted in the outgoing route.

In the maintenance cell collecting section 106-3,
After the maintenance cell signal composed of this optical cell signal is converted into an electric cell signal by the optical / electrical conversion unit 110-3, the maintenance cell monitoring unit 111-3 determines whether the maintenance cell signal should be recovered. To be done. In this case, it is determined that the maintenance cell signal should be collected, and the maintenance cell analysis unit 113-
3, the maintenance cell analysis unit 113-3 analyzes the received maintenance cell signal and obtains maintenance information such as the fact that the maintenance cell signal is transmitted regularly and its transmission time. It is given to the maintenance operation monitoring control unit 121.

Next, the operation of transmitting the maintenance cell signal to the optical ATM switch (not shown) on the downstream side will be described.

The maintenance operation monitoring control section 121 activates the maintenance cell inserting section 120 every predetermined time. In the first embodiment, the maintenance cell insertion unit 120 cyclically moves every time it is activated, the route for inserting the maintenance cell signal (hence the header processing units 102-1, ..., 102-4). It is arranged to switch the time information and the optical signal A in the data section.
A maintenance cell signal in which the identification information of the TM switch 100 is inserted is formed, and the maintenance cell is switched to a predetermined entry route via the header processing unit (here, 102-2) which is switched and selected. Insert the signal.

Such a maintenance cell signal is transferred to the buffer section 103-2 and once accumulated, and then read at a timing at which the optical switch 105 does not conflict with other cell signals. Electric / optical converter 10
After being converted into an optical cell signal in 4-2, the optical switch 105
Entered in. In the first embodiment, for example, when a maintenance cell signal is transmitted, the optical switch 105 switches the cell signal in the same manner as the cell signal immediately before the maintenance cell signal. The maintenance cell signal to be transmitted is input to the maintenance cell collection unit (here, 106-1) inserted in the outgoing route.

In the maintenance cell collecting section 106-1,
After the maintenance cell signal composed of this optical cell signal is converted into an electrical cell signal by the optical / electrical conversion unit 110-1, the maintenance cell monitoring unit 111-1 determines whether the maintenance cell signal should be recovered. To be done. In this case, the cell signal for maintenance is inserted by the optical ATM switch 100, so it is determined that the cell signal is not to be collected, and the maintenance cell monitoring unit 111-1 transfers it to the electrical / optical conversion unit 112-1. The maintenance cell signal is given and output.

Therefore, according to the first embodiment, the ATM
Even when a switch that exchanges optical cell signals is applied to the switch, it is possible to insert the maintenance cell signal into the network and recover the maintenance cell signal from the network.
Maintenance and operation functions can be further enhanced.

Further, according to the first embodiment, the maintenance cell signal is inserted into the network via the header processing units 102-1, ..., 102-4, so that the insertion structure is simple. In addition, the insertion can be executed at an appropriate timing. For example, the optical / electrical conversion unit 1
When an optical multiplexer is provided in the preceding stage of 01-1, ..., 101-4, or an optical multiplexer is provided in the preceding stage of the optical switch 105 and is inserted, timing adjustment with other cell signals is performed. It cannot be performed properly.

Further, according to the first embodiment, the insertion point of the maintenance cell signal into the network and the recovery point of the maintenance cell signal from the network are selected as shown in FIG. It is possible to obtain very effective delay time information. The transmission delay time is used for checking the quality of the line, but this time is not sufficient only for the optical fiber, and the processing delay time in the exchange should also be reflected. The largest cause of fluctuations in the processing delay time in the exchange is fluctuations in the accumulation time in the buffer units 103-1, ..., 103-4 (due to contention adjustment), and as shown in FIG. 1, the buffer units 103-1 ,. , 103-4 inserts a cell signal for maintenance on the front side of the buffer units 103-1, ..., 103.
It is preferable to collect the maintenance cell signal on the rear side of -4.

Furthermore, according to the first embodiment, the maintenance cell signals can be inserted into the network from all the incoming routes, and the maintenance cell collecting unit 106-inserted in all the outgoing routes. Since 1 to 106-4 are adapted to collect the maintenance cell signal, the transmission delay time information can be obtained for all the routes that are the combination of the ingress route and the egress route, if necessary.

By the way, it has been considered that a general cell signal and a maintenance cell signal are transmitted between both optical ATM exchanges by different wavelengths or polarization states (angles of polarization planes). Even in such a case, the maintenance cell signal can be recovered by the configuration of the first embodiment, that is, the maintenance cell signal with accurate transmission delay time passing through the buffer section in the exchange can be recovered. By the way, in the study stage, a structure for separating a general cell signal and a maintenance cell signal according to the wavelength and the polarization state (angle of the polarization plane) is provided at the first stage of the optical ATM switch to collect them. Was becoming.

(B) Second Embodiment Next, a second embodiment in which the optical packet switch according to the present invention is applied to an optical ATM switch for an ATM network will be described in detail with reference to the drawings. FIG. 4 shows the configuration of the optical ATM switch of the second embodiment, and the same or corresponding parts as those in FIG. 1 according to the first embodiment described above are designated by the same reference numerals.

The second embodiment differs from the first embodiment in the exchange means for guiding the received optical cell signal to the outgoing route, and the characteristic configuration of the first embodiment concerning the insertion and recovery of the maintenance cell signal. Is the same in the second embodiment. That is, in the second embodiment, the star coupler unit 132 and the wavelength selection filter 13 are used instead of the optical switch 105 of the first embodiment as a switching means for guiding the received optical signal to the outgoing route.
3-1 to 133-4 are provided, and the electric / optical conversion units 131-1 to 131-4 in the next stage of the buffer units 103-1 to 103-4 are the same as those in the first embodiment. Unlike the electric / optical conversion units 104-1, ..., 104-4, they have a variable wavelength configuration.

In the case of the second embodiment, a header analysis result is given from each of the corresponding header processing units 102-1, ..., 102-4 to each of the electric / optical conversion units 131-1 ,. , 131-4 output to the star coupler section 132 optical cell signals having wavelengths λ 1, ..., λ 4, respectively, which are set in the output path according to the analysis result. To do. In addition, all the electrical / optical conversion units 1
A competition control unit (not shown) is provided in relation to 31-1, ..., 131-4, and a plurality of optical cell signals having the same wavelength do not exist at the output end from the star coupler unit 132 at the same time. ing.

Electric / optical converter 13 capable of varying output wavelength
Examples of the 1-1, ..., 131-4 include, for example, a plurality of laser diodes having different output wavelengths, which selectively drive any one of the laser diodes, or only an optical signal from any one of the laser diodes. One of them can be selectively output.

The star coupler section 132 has, for example, a 4-input 4-output configuration composed of four star coupler elements of 1-input and 4-output. Star coupler unit 13
The optical cell signal input to any one of the two input terminals is distributed and given to all the output terminals of the star coupler unit 132.

A wavelength selection filter 133-1 and a wavelength selection filter 133-1 are provided at the respective output paths connected to the respective output terminals of the star coupler section 132.
.., 133-4 are inserted, and the same maintenance cell collection units 106-1, ..., 106-4 as in the first embodiment are provided at the subsequent stages of the respective wavelength selection filters 133-1 ,. It is provided.

Each wavelength selection filter 133-1, ..., 13
3-4 are respectively selected so as to pass different wavelength components λ1, ..., λ4.

Therefore, in this second embodiment, when a normal optical cell signal having a destination related to the third outgoing route is transmitted, it is converted into an electric cell signal in the same manner as in the first embodiment. The converted data is once stored in the buffer unit 103-1 and then read out and input to the electrical / optical conversion unit 131-1 to be converted into an optical cell signal having a wavelength λ3 related to the third output route and then converted into a star signal. It is input to the coupler unit 132 and given to all outgoing routes. However, only the wavelength selection filter 133-3 on the third outgoing route can pass this optical cell signal, and the maintenance cell recovery unit 106-3 confirms whether this optical cell signal is the maintenance cell signal. , A negative result is obtained and is output from the output terminal OUT-3 as it is.

Next, the operation when the maintenance cell signal is transmitted will be described for the electrical / optical conversion section (here, 131-2). For example, if the same path as the immediately preceding cell signal (outgoing path 1) is used for the maintenance cell signal, the electrical / optical conversion unit 131-2 causes the wavelength corresponding to the first outgoing path. It is converted into an optical cell signal having λ1 and input to the star coupler unit 132, and thus the maintenance cell signal composed of an optical signal is given to all output routes. But,
Only the wavelength selection filter 133-1 on the first outgoing path can pass this optical cell signal, and this optical cell signal is given to the maintenance cell recovery unit 106-1 to check whether it is the maintenance cell signal. To be done. At this time, since it is the maintenance cell signal, the maintenance cell collection unit 106-1 performs collection.

The description of the operation of inserting the maintenance cell signal will be omitted. Also in the description of the third and subsequent embodiments described later, the description of the operation of inserting the maintenance cell signal is omitted.

As described above, the second embodiment is different from the first embodiment only in the cell signal exchange structure, and the maintenance cell signal insertion structure and recovery structure are different from those in the first embodiment. Since it is similar, the same effect as the first embodiment can be obtained.

(C) Third Embodiment Next, a third embodiment in which the optical packet switch according to the present invention is applied to an optical ATM switch for an ATM network will be described in detail with reference to the drawings. FIG. 5 shows the configuration of the optical ATM switch of the third embodiment, and the same or corresponding portions as those in FIG. 1 according to the first embodiment described above are designated by the same reference numerals.

In the optical ATM switch 100 of the first embodiment, buffer units 103-1, ..., 103-4 for timing adjustment when cell signals to the same outgoing route compete are provided on the input side of the switching configuration. However, the optical ATM switch 140 of the third embodiment has a buffer unit 103-1 for timing adjustment when cell signals to the same outgoing route compete with each other,
..., 103-4 is provided on the output side of the exchange configuration.

That is, in FIG. 5, the electric cell signals from the respective header processing units 102-1, ..., 102-4 are directly applied to the corresponding electric / optical conversion units 104-1 ,. On the other hand, in each of the maintenance cell collection units 106-1, ..., 106-4, the optical / electrical conversion units 110-1, ..., 110-4 and the maintenance cell monitoring unit 111-1 ,. Buffer unit 103-between 111-4
1, ..., 103-4 are inserted. Before reaching these buffer units 103-1, ..., 103-4, since there is no competition of cell signals, the buffer units 103-1,
..., so that different cell signals do not flow through the same route before reaching 103-4, the optical switches 120-1,
, 120-4 are provided, and each of the optical / electrical conversion units 110-1, ..., 110-4 has a 4-input 4-output configuration.

Each optical switch 120-1, ..., 120-4
Have a one-input and four-output configuration, and perform switching to a predetermined output route according to the header analysis result from the corresponding header processing units 102-1, ..., 102-4. Each optical / electrical converter 110-1, ..., 11
0-4 are all the optical switches 120-1 to 12-12, respectively.
An optical cell signal from 0-4 (incoming route) to the same outgoing route is given (thus, four cell signals may be inputted at the same time), and the inputted optical cell signal is inputted. Is converted into an electric cell signal, and the corresponding buffer unit 1
03-1, ..., 103-4. Each buffer unit 10
.., 103-4 distinguishably store the cell signals related to the respective incoming routes, and perform competition adjustment to output the cell signals from any one of the incoming routes.

In other words, in the third embodiment, the transmitted cell signal is appropriately processed and subjected to a predetermined output before reaching the buffer units 103-1, ..., 103-4 without competition adjustment. Maintenance cell collection unit (106-
1, ..., 106-4), and the buffer sections 103-1, ...

Therefore, the third embodiment is different from the first embodiment only in the cell signal contention adjustment configuration.
Since the maintenance cell signal insertion configuration and the recovery configuration are the same as those in the first embodiment, the third embodiment can also obtain the same effect as that of the first embodiment.

(D) Fourth Embodiment Next, a fourth embodiment in which the optical packet switch according to the present invention is applied to an optical ATM switch for an ATM network will be described in detail with reference to the drawings. FIG. 6 shows the configuration of the optical ATM switch of the fourth embodiment, and the same or corresponding portions as those in FIG. 1 according to the first embodiment described above are designated by the same reference numerals.

Optical ATM switch 150 of the fourth embodiment.
Is the optical ATM switch 10 of the first to third embodiments described above.
Compared with 0, 130, and 140, the configuration of the maintenance cell recovery unit is made smaller and simpler, and the optical AT for cell signals other than the maintenance cell signals to be recovered is provided.
This is intended to minimize the transmission delay time in the M switch. Compared with the first embodiment, the processing contents of the header processing units 102-1, ..., 102-4 are slightly different, and the wavelength selection filter 152 with the demultiplexing function is also provided.
The difference is that -1 to 152-4 are provided,
Furthermore, the electrical / optical conversion units 104-1 to 104 having arbitrary wavelengths
-4 instead of -4, wavelength-variable electric / optical converters 151-1 to 151-1
51-4 is different, and furthermore, the maintenance cell collection units 153-1 to 15-1 have a simple internal structure.
The difference is that 53-4 is provided.

In FIG. 6, each of the header processing units 102-1, ..., 102-4 in this embodiment sends the result information obtained by the header analysis to not only the optical switch 105 but also the corresponding electric / optical conversion unit 151. , ..., 151-4. Information necessary for routing is given to the optical switch 105, while the electrical / optical conversion units 151-1, ..., 151- are provided.
A signal for distinguishing whether the transmitted cell signal is a maintenance cell signal or another general cell signal is given to 4.

Each electric / optical conversion unit 151-1, ..., 151
-4 are corresponding buffer units 103-1, ...,
When the cell signal from 103-4 is a maintenance cell signal to be recovered, it is converted into an optical cell signal having a wavelength λ10, and the cell signal from the corresponding buffer unit 103-1, ..., 103-4 is a general cell. In the case of a signal (including a maintenance cell signal inserted in the optical ATM switch 150), it is converted into an optical cell signal having a wavelength λ11 and given to the optical switch 105.

Wavelength selection filter 152 with each demultiplexing function
, ..., 152-4 are connected to the corresponding output terminals of the optical switch 105. The wavelength selection filters 152-1, ..., 152-4 with demultiplexing functions are respectively provided in the optical switch 1.
When the wavelength of the optical cell signal from 05 is λ11, the output terminal OU
The optical cell signal is output from T-1, ..., OUT-4. On the other hand, the wavelength selection filter with each demultiplexing function 152-
1, ..., 152-4 give the optical cell signals to the maintenance cell recovery units 153-21, ..., 153-4 corresponding to the wavelength of the optical cell signals from the optical switch 105 being .lamda.10, respectively. These wavelength selection filters 152-1, ..., 1
52-4 is realized by an optical demultiplexer, for example.

As described above, the electric / optical converters 151-1 to 151-1
Since 151-4 is performing the electric / optical conversion, all the optical cell signals given to the maintenance cell collection units 153-1, ..., 153-4 are maintenance cell signals to be collected.

Each of the maintenance cell collection units 153-1, ..., 15
3-4 are optical / electrical converters 110-1, ..., 1 respectively.
10-4 and maintenance cell analysis unit 113-1, ..., 113
It becomes -4. These optical / electrical conversion units 110-1 to 110
-4 and the functions of the maintenance cell analysis units 113-1 to 113-4 are the same as those of the first embodiment, and the description thereof will be omitted.

In the fourth embodiment having the above-mentioned configuration, it is assumed that a normal optical cell signal having the destination associated with the first outgoing route is transmitted and input from the input terminal IN-2. Also in this case, similarly to the first embodiment, it is converted into an electric cell signal and temporarily stored in the buffer unit 103-2,
Then, it is read and input to the electric / optical conversion unit 151-2. Since it is a general cell signal, the electrical / optical conversion unit 15
By 1-2, it is converted into an optical cell signal having a wavelength λ11 instructing that and inputted to the optical switch 105,
It is exchanged by the optical switch 105 and input to the wavelength selection filter 152-1. Since the wavelength of this optical cell signal is λ11, the wavelength selection filter 152-1 outputs this optical cell signal as it is from the output end OUT-1.

On the other hand, it is assumed that the maintenance cell signal is transmitted and input to the input terminal IN-1. Again, for example,
For the maintenance cell signal, it is assumed that the same path as the cell signal immediately before (the output path 3) is used. Electric / optical converter 1
Since the processing before reaching 51-1 is almost the same as the case where a general cell signal is transmitted, the description thereof will be omitted.
The electrical / optical converter 151-1 converts the electrical cell signal from the buffer unit 103-1 into an optical cell signal having the wavelength λ10 based on the information from the header processing unit 102-1 and inputs the optical cell signal to the optical switch 105. . The optical cell signal is exchanged by the optical switch 105 and the wavelength selection filter 152-.
Input to 3. Since the wavelength of this optical cell signal is λ10 (that is, it is a maintenance cell signal), the wavelength selection filter 152-3 gives this optical cell signal to the maintenance cell recovery unit 153-3.

In the maintenance cell collecting section 153-3,
The optical / electrical conversion unit 110-3 converts this optical cell signal (maintenance cell signal) into an electric cell signal, and the maintenance cell analysis unit 1
13-3, the maintenance cell analysis unit 113-3 analyzes the received maintenance cell signal, and supplies the maintenance operation monitoring control unit 121 with the maintenance information obtained by the analysis or the like.

Therefore, according to the fourth embodiment as well, the AT
Even when an optical switch for exchanging optical cell signals is applied to the M switch, the maintenance cell signal can be inserted into the network and the maintenance cell signal can be recovered from the network.
The maintenance and operation functions can be further enhanced, and the insertion and recovery points of the maintenance cell signal are almost the same as those in the first embodiment, so that the effects other than the above according to the first embodiment can be obtained similarly. it can.

Furthermore, according to the fourth embodiment, the structure of the maintenance cell recovery unit can be made small and simple, and the power consumption can be reduced, and the cell signals other than the maintenance cell signals to be recovered can be obtained. It is possible to reduce the transmission delay time in the optical ATM switch with respect to.

(E) Fifth Embodiment Next, a fifth embodiment in which the optical packet switch according to the present invention is applied to an optical ATM switch for an ATM network will be described in detail with reference to the drawings. FIG. 7 shows the configuration of the optical ATM switch of the fifth embodiment. The same or corresponding parts as those of FIGS. 1 and 6 according to the first and fourth embodiments described above are designated by the same reference numerals. Is shown.

Optical ATM switch 160 of the fifth embodiment.
Also, similar to the optical ATM switch 150 of the fourth embodiment, the optical ATM switches 100 and 130 of the above-described first to third embodiments are also provided.
And 140, the configuration of the maintenance cell recovery unit is made smaller and simpler, and the transmission delay time in the optical ATM switch for cell signals other than the maintenance cell signal to be recovered is minimized. I tried to make it smaller.

Optical ATM switch 15 of the fourth embodiment described above.
0 is for recovering the maintenance cell signal by making it possible to distinguish the maintenance cell signal of the recovery target of the optical signal state from the general cell signal according to the wavelength. The ATM switch 160 collects the maintenance cell signal by making it possible to distinguish the maintenance cell signal of the recovery target of the optical signal state and the general cell signal by the plane of polarization (polarization plane).

The optical ATM switch 160 of the fifth embodiment is (1) compared with the fourth embodiment, (1) a maintenance cell signal to be recovered or a general cell signal (including a maintenance cell signal inserted by the switch). Header processing units 102-1, ..., 10 representing
The analysis result information from 2-4 corresponds to the corresponding polarization controller 16
1-1, ..., 161-4, (2) Fixed-wavelength optical cell signals (polarization control sections 161-1, ..., Next to each buffer section 103-1 ,. 161-4, which may or may not be polarized light) is provided with electric / optical conversion units 104-1 to 104-4, (3) Electric / optical conversion units 104-1 To 104-4 and the optical switch 105, each header processing unit 102-1
, 161-4 for outputting an optical cell signal obtained by polarizing the polarization plane of the input optical cell signal in accordance with the analysis result information from 102-4. (4) Wavelength selection filter with demultiplexing function 152-
1, ..., 152-4 in place of the polarization splitting unit 162-1,
The difference is that 162-4 are provided.

Here, the polarization control units 161-1 to 161-
4 and various types of polarized wave demultiplexing units 162-1 to 162-4 are applicable, for example, the following types are applicable. Polarization control units 161-1 to 161-4
And the polarization separation units 162-1 to 162-4
A mode converter or a mode splitter can be applied (for example, Reference 3, “Nishihara et al.,“ Optical Integrated Circuit ”, published by Ohmsha,
pp271-275, pp315-316, 1985 "). Also,
A Faraday effect element or the like is also applicable.

In the fifth embodiment having the above-mentioned configuration, it is assumed that a general optical cell signal having the destination associated with the first outgoing route is transmitted and input from the input terminal IN-2. Also in this case, similarly to the first embodiment, it is converted into an electric cell signal and temporarily stored in the buffer unit 103-2,
After that, it is read out, input to the electrical / optical conversion unit 104-2, converted into an optical cell signal, and input to the polarization control unit 161-2. Since it is a general cell signal, the polarization controller 16
The polarization state (S) for a general cell signal is input to the optical switch 105 by 1-2, and is input to the optical switch 105, exchanged by the optical switch 105, and input to the polarization demultiplexing unit 162-1. Since the polarization state S of this optical cell signal indicates a general cell signal, the polarization demultiplexing unit 162-1 outputs this optical cell signal as it is from the output end OUT-1.

On the other hand, it is assumed that the maintenance cell signal is transmitted and input to the input terminal IN-1. Again, for example,
For the maintenance cell signal, it is assumed that the same path as the cell signal immediately before (the output path 3) is used. Polarization controller 161
Since the processing before reaching -1 is almost the same as the case where a general cell signal is transmitted, the description thereof will be omitted. The polarization control unit 161-1 sets the optical cell signal from the electrical / optical conversion unit 104-1 to the polarization state (P) related to the maintenance cell signal based on the information from the header processing unit 102-1. It is converted into an optical cell signal that it has and input to the optical switch 105. This optical cell signal is exchanged by the optical switch 105 and input to the polarization demultiplexing unit 162-3. Since the polarization state P of this optical cell signal indicates the maintenance cell signal, this optical cell signal (maintenance cell signal) is the polarization demultiplexing unit 1.
62-3 is given to the maintenance cell collection unit 153-3,
Similar to the fourth embodiment, the maintenance cell collecting unit 153-3.
Be recovered by.

Therefore, according to the fifth embodiment as well, the AT
Even when an optical switch for exchanging optical cell signals is applied to the M switch, the maintenance cell signal can be inserted into the network and the maintenance cell signal can be recovered from the network.
The maintenance and operation functions can be further enhanced, and the insertion and recovery points of the maintenance cell signal are almost the same as those in the first embodiment, so that the effects other than the above according to the first embodiment can be obtained similarly. it can.

Further, according to the fifth embodiment as well, the structure of the maintenance cell recovery unit can be made small and simple, and the power consumption can be reduced, and the optical ATM switch for cell signals other than the maintenance cell signal to be recovered can be obtained. The transmission delay time can be reduced.

(F) Sixth Embodiment Next, a sixth embodiment in which the optical packet switch according to the present invention is applied to an optical ATM switch for an ATM network will be described in detail with reference to the drawings. FIG. 8 shows the structure of the optical ATM switch of the sixth embodiment. The same or corresponding parts as those in FIGS. 4 and 6 according to the second and fourth embodiments described above are designated by the same reference numerals. Is shown.

Optical ATM switch 170 of the sixth embodiment.
Is different from the optical ATM switch 130 of the second embodiment in that a star coupler section is mainly used to guide the received optical cell signal to the output path and the wavelength difference is the same as in the optical ATM switch 150 of the fourth embodiment. It has a configuration that is combined with a recovery cell recovery configuration that utilizes the.

Therefore, in the following, the components will be described only for the electrical / optical conversion units 171-1, ..., 171-4, and the operation will be described immediately.

Each of the electric / optical conversion units 171-1, ..., 171
-4 corresponds to the corresponding header processing unit 102-1 and
From 102-4, header analysis information for routing is given, as well as header analysis information indicating a maintenance cell signal to be recovered or a general cell signal. The electric / optical conversion units 171-1, ..., 171-4 are respectively
The inputted electric cell signal can be converted into an optical cell signal so as to have any one of the eight kinds of wavelengths λ21 to λ28. Each electric / optical converter 171-1, ..., 171
-4 selects the wavelength determined by the combination of the output route and whether or not the maintenance cell signal to be recovered, as the wavelength of the optical cell signal to be output.

In the optical ATM switch 170 of the sixth embodiment, it is assumed that a general optical cell signal having a destination related to the first outgoing route is transmitted to the input terminal IN-2. In this case, the processing up to the buffer unit 103-2 is similar to that of the second embodiment, and therefore its explanation is omitted. Buffer unit 103
-2, the electric cell signal read from
1-2 is converted into an optical cell signal having a wavelength λ21 associated with the combination of the first output path and the general cell signal by the electric / optical conversion section 171-2, and then the star coupler section 172. Selection filters 173-1 to 173 with a demultiplexing function that are input to all the output routes
Given to 4. However, since this optical cell signal has the wavelength λ21, only the wavelength selective filter 173-1 with the demultiplexing function on the first output path outputs this optical cell signal to the output terminal OU.
It can be passed to the T-1 side and is output as it is from the output terminal OUT-1.

Next, the operation when the maintenance cell signal is transmitted to the input terminal IN-1 will be described with reference to the electric / optical conversion unit 171-.
1 and subsequent will be described. Here, for example, for the maintenance cell signal, the same route (egress route 3
Is used), the electric / optical conversion unit 171-1
Converts the electric cell signal from the buffer unit 103-1 into an optical cell signal having a wavelength λ27 related to the combination of the third output route and the maintenance cell signal, and inputs the optical cell signal to the star coupler unit 172. Then, the wavelength selection filters 173-1 to 173-4 with the demultiplexing function are provided in all the outgoing routes. Since this optical cell signal has the wavelength λ27, the wavelength selection filter 173-3 with the demultiplexing function on the third output path is provided.
Only the optical cell signal is sent to the maintenance cell collection unit 153-3.
Can be passed to the side, similar to the fourth embodiment,
It is collected by the maintenance cell collection unit 153-3.

Optical ATM switch 170 of the sixth embodiment.
Is a second means for guiding the received optical cell signal to the outgoing route.
Although an optical ATM switch 130 such as that of the embodiment centering around a star coupler unit is applied, the processing configuration of the maintenance cell signal is the same as that of the optical ATM switch 150 of the fourth embodiment, and as a result, The same effect as the fourth embodiment can be obtained.

(G) Seventh Embodiment Next, a seventh embodiment in which the optical packet switch according to the present invention is applied to an optical ATM switch for an ATM network will be described in detail with reference to the drawings. FIG. 9 shows the configuration of the optical ATM switch of the seventh embodiment, and the same or corresponding portions as those in FIG. 8 according to the sixth embodiment described above are designated by the same reference numerals.

In the case of the optical ATM switch 170 of the sixth embodiment, each of the electric / optical conversion units 171-1, ..., 171-4 is eight.
It is compatible with wavelengths and its structure is complicated.
The optical ATM switch 180 of the seventh embodiment takes this point into consideration, and each electric / optical conversion unit 171-1, ..., 1
This is to reduce the number of wavelength types of the optical cell signal output from 71-4, and to simplify the configuration of the latter stage side of the star coupler unit 172.

Each electric / optical converter 171-1, ..., 171
-4 are corresponding buffer units 103-1, ...,
The electric cell signal from 103-4 is converted into an optical cell signal having a wavelength according to whether or not it is a maintenance cell signal to be recovered, and in the case of a general cell signal. That is, when the input electric cell signal is a general cell signal (including the maintenance cell signal inserted in the exchange), it is converted into an optical cell signal having wavelengths λ21, ..., λ24 corresponding to the output path and input. When the electric cell signal is a maintenance cell signal, the electric cell signal is converted into an optical cell signal having a wavelength λ30 corresponding to the signal and is input to the star coupler unit 172.

The star coupler section 172 in this embodiment is
It has four input terminals and five output terminals. Even if an optical cell signal is input from any of the input terminals, the optical cell signal is distributed to all five output terminals.

The four output terminals of the star coupler section 172 are
The wavelength selection filter 173- interposed on each outgoing route
1 to 173-4. The wavelength selection filters 173-1, ..., 173-4 of this embodiment are respectively
Only the optical cell signals of the wavelengths λ21, ..., λ24 assigned to itself are passed.

The remaining output terminals of the star coupler section 172 are
It is connected to the recovery-use wavelength selection filter 181. The recovery-dedicated wavelength selection filter 181 passes only the optical cell signal having the wavelength λ30, that is, the optical cell signal of the maintenance cell signal to be recovered, and is similar to the fourth to sixth embodiments,
Moreover, it is given to the maintenance cell collection unit 153 common to each entry route.

In the optical ATM switch 180 of the seventh embodiment, it is assumed that a general optical cell signal having a destination related to the first outgoing route is transmitted to the input terminal IN-2. In this case, the processing up to the buffer unit 103-2 is similar to that of the sixth embodiment, and therefore its explanation is omitted. Buffer unit 10
The electric cell signal read from 3-2 is converted into the electric / optical conversion unit 1.
71-2, and is converted into an optical cell signal having a wavelength λ21 because it is a general cell signal to the first output path by the electric / optical conversion section 171-2 and input to the star coupler section 172. The selected wavelength filters 173-1 to 173 are inserted into all the outgoing routes and the maintenance cell recovery routes.
-4 and 181. However, since this optical cell signal has the wavelength λ21, only the wavelength selection filter 173-1 on the first output path can pass this optical cell signal, and it is output as it is from the output terminal OUT-1.

Next, the operation when the maintenance cell signal is transmitted to the input terminal IN-1 will be described with reference to the electric / optical conversion unit 171-.
1 and subsequent will be described. Here, for example, for the maintenance cell signal, the same route (egress route 3
Is used), the electric / optical conversion unit 171-1
Converts the electric cell signal from the buffer unit 103-1 into an optical cell signal having a wavelength λ30 based on the fact that it is a maintenance cell signal and inputs the optical cell signal to the star coupler unit 172. The wavelength selection filters 173-1 to 173-4 and 181 are inserted in the maintenance cell recovery path. Since this optical cell signal has the wavelength λ30, only the recovery dedicated wavelength selection filter 181 can pass this optical cell signal to the common maintenance cell recovery section 153 side.
The cells are recovered by the maintenance cell recovery unit 153 in the same manner as in the sixth embodiment.

Optical ATM switch 180 of the seventh embodiment.
The basic recovery method is similar to that of the sixth embodiment, and as a result, the same effect as that of the sixth embodiment can be obtained. In addition to this, there is an effect that the structure can be simplified more than the sixth embodiment.

(H) Eighth Embodiment Next, an eighth embodiment in which the optical packet switch according to the present invention is applied to an optical ATM switch for an ATM network will be described in detail with reference to the drawings. FIG. 10 shows the configuration of the optical ATM switch of the eighth embodiment. The same or corresponding parts as those of FIGS. 4 and 7 according to the second and fifth embodiments described above are designated by the same reference numerals. Is shown.

The optical ATM switch 190 of the eighth embodiment.
Is a configuration for guiding a received optical cell signal centered on a star coupler unit such as the optical ATM switch 130 of the second embodiment to an output path, and a polarization state like the optical ATM switch 160 of the fifth embodiment. The configuration has a configuration in which a maintenance cell signal recovery configuration that utilizes the difference of 1) is combined.

Therefore, in the following, the description of the components will be omitted and the operation will be described immediately.

In the optical ATM switch 190 of the eighth embodiment, it is assumed that a general optical cell signal having a destination associated with the first outgoing route is transmitted and input from the input terminal IN-2. In this case as well, the signal is converted into an electric cell signal and temporarily stored in the buffer unit 103-2, then read and input to the electric / optical conversion unit 131-2. In the electric / optical conversion unit 131-2, the inputted electric cell signal is converted into an optical cell signal having a wavelength λ1 related to the output path thereof and inputted into the polarization control unit 161-2. Since the cell signal is a general cell signal, the polarization control unit 161-2 controls the polarization state (S) for the general cell signal to control the star coupler unit 13.
Entered in 2. That is, the optical cell signal input to the star coupler unit 132 has a wavelength of λ1 and a polarization state of S. Such an optical cell signal is given to the wavelength selection filters 133-1 to 133-4 inserted in each output path via the star coupler unit 132. But,
Since this optical cell signal has the wavelength λ 1, only the wavelength selection filter 133-1 on the first outgoing path passes this optical cell signal, and this optical cell signal is transmitted to the polarization separation unit 162-1.
To reach. Since the polarization state S of this optical cell signal indicates a general cell signal, the polarization demultiplexing unit 162-1 outputs this optical cell signal as it is from the output end OUT-1.

On the other hand, it is assumed that the maintenance cell signal is transmitted and input to the input terminal IN-1. Again, for example,
For the maintenance cell signal, it is assumed that the same path as the cell signal immediately before (the output path 3) is used. Electric / optical converter 1
Since the processing before reaching 31-1 is almost the same as the case where a general cell signal is transmitted, the description thereof will be omitted.
In the electrical / optical converter 131-1, the input electrical cell signal (maintenance cell signal) is converted into an optical cell signal having a wavelength λ3 related to the output path of the cell signal immediately before, and polarization control is performed. It is input to the unit 161-1. Polarization controller 161
-1 converts the optical cell signal from the electrical / optical conversion unit 131-1 into an optical cell signal having the polarization state (P) related to the maintenance cell signal based on the information from the header processing unit 102-1. It is converted and input to the star coupler unit 132. That is, the optical cell signal input to the star coupler unit 132 is
The wavelength is λ3 and the polarization state is P. Such an optical cell signal is passed through the star coupler unit 132 and the wavelength selection filters 133-1 to 13-13 inserted in the respective output routes.
3-4, since this optical cell signal has the wavelength λ3, the wavelength selection filter 133 on the third output path is provided.
Only -3 passes this optical cell signal, and this optical cell signal reaches the polarization demultiplexing unit 162-3. Since the polarization state P of this optical cell signal indicates the maintenance cell signal, the polarization demultiplexing unit 162-3 gives this optical cell signal to the maintenance cell recovery unit 153-3, and the above-described embodiment is used. Similarly to the above, the cells are recovered by the maintenance cell recovery unit 153-3.

Optical ATM switch 190 of the eighth embodiment.
Is a second means for guiding the received optical cell signal to the outgoing route.
An optical ATM switch 130 such as the one in the embodiment is used mainly for the star coupler unit, but the processing configuration of the maintenance cell signal is the same as that of the optical ATM switch 160 in the fifth embodiment. The same effect as the fifth embodiment can be obtained.

(I) Other Embodiments The above first and third embodiments relate to the input buffer type and the output buffer type, and the second and fourth to eighth embodiments are the input buffer type. Although it is a thing, the 2nd, 4th-8th
The characteristic configuration of the embodiment may be applied to an output buffer type exchange.

The above-mentioned embodiments are shown so that the features can be easily understood, and it goes without saying that they can be applied to an exchange having other components such as a multiplexer and a demultiplexer. Therefore, the wavelength-multiplexed optical cell signal may be exchanged as long as it does not affect the above-mentioned characteristic configuration.

As for the eighth embodiment, the positional relationship between the wavelength selection filter and the polarization demultiplexer in the latter stage of the star coupler 132 may be reversed. That is, the recovered cell signal and the unrecovered cell signal may be separated in the polarized state, and then the unrecovered cell signal may be separated according to the wavelength and output.

In each of the above-mentioned embodiments, the present invention is applied to the ATM.
Although the one applied to the switching device for the network is shown, it goes without saying that the optical packet switching device of the present invention can be applied to the switching device for other switching networks.

[0124]

As described above, according to the optical packet switching apparatus of the first invention (corresponding to the first to third embodiments), the packet signal which is the optical signal after the switching processing by the switching means is electrically transmitted. Based on the optical / electrical conversion means for converting into a signal and the packet signal converted into the electric signal, it is judged whether or not the packet signal is a maintenance packet signal that needs to be recovered,
Since the packet signal is output from the optical packet switching device when collection is not necessary and the packet signal for maintenance is collected to collect the packet signal when collection is required, the switching means outputs the optical packet signal. Even if it is exchanged, the maintenance packet signal can be collected from the network, and the maintenance and operation functions can be further enhanced.

Second invention (corresponds to the fourth to eighth embodiments)
According to the optical packet switching device of the above, depending on the analysis result by the header processing means, there is a certain optical attribute depending on whether the input packet signal is a maintenance packet signal that needs to be collected or a packet signal other than that. Optical attribute changing means provided before the switching means or as an internal configuration for changing the packet signal of different optical signals, and maintenance packet collecting means for collecting the packet signal composed of the optical signal when exchanged, The packet signal of the optical signal output from the means,
Discrimination is made according to the optical attribute content of the packet signal, and when the attribute content is related to a packet signal that does not need to be collected, the packet signal is output from the optical packet switching device, and the attribute content is collected. Since the optical attribute discriminating means for giving the packet signal to the maintenance packet collecting means when it relates to the necessary packet signal is provided, even if the exchanging means exchanges the optical packet signal, it is for maintenance. Packet signals can be collected from the network with a simple and compact structure, and maintenance and operation functions can be further enhanced.

Third invention (corresponds to the first to eighth embodiments)
According to the optical packet switching device of the above, since the maintenance packet inserting means for inserting the maintenance packet signal into the network is provided with the header processing means as an entrance, the maintenance packet signal can be obtained so as to obtain good information for the maintenance operation. Can be transmitted.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment.

FIG. 2 is an explanatory diagram of a conventional problem.

FIG. 3 is an explanatory diagram showing a format example of a maintenance cell signal.

FIG. 4 is a block diagram showing a configuration of a second embodiment.

FIG. 5 is a block diagram showing a configuration of a third embodiment.

FIG. 6 is a block diagram showing a configuration of a fourth exemplary embodiment.

FIG. 7 is a block diagram showing a configuration of a fifth embodiment.

FIG. 8 is a block diagram showing a configuration of a sixth exemplary embodiment.

FIG. 9 is a block diagram showing a configuration of a seventh embodiment.

FIG. 10 is a block diagram showing the structure of an eighth embodiment.

[Explanation of symbols]

100, 130, 140, 150, 160, 70, 18
0, 190 ... Optical ATM switch, 102 ... Header processing section, 103 ... Buffer section, 104, 131, 151, 171 ... Electrical / optical conversion section, 105 ... Optical switch, 106, 153 ... Maintenance cell collecting section, 110 ... Electrical / optical conversion unit, 111 ... Maintenance cell monitoring unit, 120 ... Maintenance cell insertion unit, 121 ... Maintenance operation monitoring control unit, 132, 172 ... Star coupler unit, 133, 152, 173, 181, ... Wavelength selection filter, 161 ... Polarization control unit, 162 ... Polarization separation unit.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H04M 3/00 E 3/22 Z H04Q 3/00 9466-5K H04L 11/20 D

Claims (3)

[Claims] 1. An optical packet switching apparatus in which a switching means for guiding an input packet signal to an outgoing route handles a packet signal composed of an optical signal, wherein the packet signal composed of the optical signal after the switching processing by said switching means is converted into an electrical signal. Based on the optical / electrical conversion means for converting into the electrical signal and the packet signal converted into the electrical signal, it is judged whether or not the packet signal is a maintenance packet signal that needs to be recovered. An optical packet switching device, comprising: a packet signal for maintenance, which outputs a packet signal from the optical packet switching device and collects the packet signal when the packet signal needs to be collected. 2. The header processing means guides the packet signal input by the switching means to the output route according to the information obtained by analyzing the packet signal input by the header processing means, wherein the switching means outputs an optical signal packet. In an optical packet switching device that handles signals, depending on the result of analysis by the header processing means, there are certain optical attributes depending on whether the input packet signal is a maintenance packet signal that needs to be collected or another packet signal. Optical attribute changing means provided before or as an internal configuration of the switching means for changing the packet signals of different optical signals to each other, and maintenance packet collecting means for collecting the optical signal packet signal when given. , The packet signal of the optical signal output from the switching means,
Discrimination is made according to the optical attribute content of the packet signal, and when the attribute content is related to a packet signal that does not need to be collected, the packet signal is output from the optical packet switching device, and the attribute content is collected. An optical packet switching device comprising: an optical attribute discriminating means for giving the packet signal to the maintenance packet collecting means when it relates to a necessary packet signal. 3. The header processing means guides the packet signal input by the switching means to the output route according to the information obtained by analyzing the packet signal input by the header processing means, and the switching means outputs the packet of the optical signal. An optical packet switching apparatus for handling a signal, comprising: a maintenance packet inserting means for inserting a maintenance packet signal into a network with the header processing means as an entrance.