JP3367499B2 - Ultra-high-speed network construction method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrahigh-speed network construction method using an add / drop circuit and a bus load balancing technology in which the network is configured in a ring shape in an ultrahigh-speed network realized by a wavelength multiplexing method. .

[0002]

2. Description of the Related Art Information flowing through networks is rapidly increasing with the spread of the Internet. The capacity of the network deployed in the conventional backbone tends to be incapable of supporting the transfer of these increasing amounts of information, and the transfer capacity of the information required for the backbone network, that is, the bandwidth of the network is dramatically increased. Is required.

As a network that can meet these requirements, WDM (Wavelength) using optical technology is used.
Division Multiplexing (wavelength division multiplexing) or a network having an optical interface can be considered.

A switching technique using an optical element is still under development, and it is not realistic to develop a device for switching a large capacity using the optical element. Also, considering the configuration on the extension line of the conventional technology, it will be realized by an n × n switch using an electric circuit, and the line speed per line input to the switch will be high or the line speed will be input. As the n value of the number of lines to be used increases, the switch speed of n × n increases and the scale of hardware also increases.
Further, there is a problem that the processing speed has an upper limit and the input line speed is limited.

In order to deal with such a problem, if the processing information is developed by parallel expansion, it is necessary to increase the number of parallel expansions as the speed increases, resulting in an increase in hardware scale. Become.

When a non-blocking network is to be constructed, the local networks 1004 are connected in a mesh form to form a network as shown in the network configuration diagram of FIG.
In this case, ultra-high speed network (WDM network)
Assuming that the number of local networks 1004 connected to 1001 is n, the number of lines connected from each local network 1004 is n−1 lines, and a line is added every time the number of local networks 1004 connected to the ultra high speed network 1001 increases. It will be necessary to re-install, and the number of connection lines will increase, and the network itself will become complicated. Each line here is wavelength-multiplexed (WDM line), and the local networks 1004 are connected by a large capacity line.

As described above, the ultra high speed network 100
It is necessary to increase the capacity of the line connecting the networks as the amount of information flowing over the network increases. In this case, WDM
In networks using technology, this is handled by increasing the number of wavelengths to be multiplexed. However, ultra-high speed network 1
When the number of connected local networks 1004 increases, it is necessary to connect each network in a one-to-one manner as the number of connected networks increases, which causes a problem of complicated addition.

Furthermore, when data of an extremely high-speed optical wavelength division multiplexing network is taken into each local network, a data overflow or the like occurs at a network connection point due to a difference in transfer information speed or a difference in data processing capability in the local network. This has been an obstacle to freely connecting local networks of various sizes.

Under such circumstances, Japanese Patent Laid-Open No. 7-23130
In the invention described in Japanese Patent Publication No. 5, an add-drop multiplexer is used to configure a network in a ring shape, and a multi-wavelength light source supplies wavelength-multiplexed light to each node. It discloses an optical wavelength division multiplexing network having means for modulating the. However, even in the above-mentioned related art, regarding the flexibility of changing the network configuration and the method for absorbing the speed difference of the transfer information generated when the data of the high-speed optical wavelength division multiplexing network is dropped at each node, I haven't listed it at all.

[0010]

SUMMARY OF THE INVENTION According to the present invention, when constructing an ultra-high speed network realized by a wavelength multiplexing system, the network is configured in a ring shape, not by a large capacity crossbar switch or the like. And a simple Add
An object of the present invention is to provide an ultra-high-speed network construction method that simplifies the network and device configuration by using the load balancing technology of the / Drop circuit and the bus, and provides more flexible network expandability.

[0011]

An ultra-high-speed network construction method of the present invention is configured such that a ring-shaped WDM network realized by a wavelength multiplexing method is connected to the WDM network by an Add / Drop device, and a plurality of user terminals are connected. An ultra-high-speed network composed of a plurality of accommodating local networks, wherein the Add / D
The rop device transfers a signal for m wavelengths input from the WDM network to a wavelength demultiplexing circuit that separates each wavelength by wavelength, and transfers the information of each demultiplexed wavelength to the local network side, or directly through the Add circuit to the WDM network. Drop circuit for each wavelength that determines whether to pass to the side,
It includes a band sharing circuit that shares the band of the information for which the Drop determination is made by the Drop circuit with a line for m wavelengths and connects it to a local network.

Further, in the Add / Drop apparatus of the present invention, the Drop circuit provided for each wavelength is
The input information for performing the Drop in the Drop device is provided with n provided at the connection point with the local network.
It has means for separating the input ports by the number of × n packet switches and inputting them into the band sharing circuit.

Further, the Add / Drop device of the present invention determines the output line according to the transfer destination of the signal received from the local network via the n × n packet switch and transfers it to the Add circuit of the subsequent stage. The add circuit has an output line selection circuit for controlling the contention of the information that passes through the local network without being dropped and the output of the transfer information from the local network transmitted from the output line selection circuit. It has a means to transfer at a wavelength specified in the network.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, when constructing an ultrahigh-speed network realized by a wavelength multiplexing system, the network is configured in a ring shape and a simple Add / Drop circuit and a bus load balancing technique are used. Thus, the network and device configuration are simplified, and an ultra-high-speed network construction method with more flexible network expandability is provided.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a block diagram of an ultrahigh-speed network according to the present invention. Ultra-high-speed networks use wavelength division multiplexing technology (W
An ultra-high speed network (WDM network) 101 connected by an optical interface using DM) and a local network group 1 configured by a conventional network
04, the user terminal 105 and another local network are connected to each local network 104 to form the entire network.

As described above, the network transfers (Drops) information destined for the local network 104 at the connection point between the ultra-high-speed network 101 and the local network 104, and at the same time, the local network 10
4 to transfer information to the ultra-high speed network 101 (Ad
d) connected by Add / Drop 102 used to Furthermore, the ultra-high speed network 10
A network interface unit 103 is provided for matching the interfaces at the connection points between the network 1 and the local network 104.

Next, FIG. 2 shows a configuration diagram of the Add / Drop portion. FIG. 2 is a configuration diagram of the Add / Drop unit of the present invention.

The interface of the part connected to the ultra-high-speed network 101 in Add / Drop 102 in FIG. 1 is an optical interface by WDM, and is connected to a network in which m wavelengths are multiplexed.

As shown in FIG. 2, the Add / Drop 102 has a wavelength separation circuit 201 for separating a signal input from a WDM network into wavelengths (λ1 to λm).
And the Drop circuit 202 that determines whether to transfer the separated wavelength information to the local network side or to pass through the branch point of the Drop circuit 202 and exit to the WDM network side via the Add circuit 208.
It is configured by a band sharing circuit 203 that shares the band of information for which Drop determination is performed by the circuit with a line for m wavelengths and is connected to a local network.

At the connection point between the ultra high speed network and the local network, it is connected to the n × n packet switch 205 provided at the input point of the local network 104, but as a countermeasure when the interface with the ultra high speed network side is different. , Deploy a network interface 204 at the network connection point.

In the route from the local network to the ultra high speed network, the information output from the n × n packet switch 206 provided at the output point of the local network is connected to the output line selection circuit 207 via the network interface 204. To be done.

Regarding the network interface 204, the conditions are the same as those described when the information is taken into the local network. Output line selection circuit 2
The output line is determined by 07, and the Add circuit 208 of the corresponding line is determined.
Transfer information to. The Add circuit 208 controls contention between information that passes through the local network without being dropped and information that is transferred from the local network.
Transfer at specified wavelength to ultra-high speed network. The wavelength to be transferred differs in each Add circuit 208, and the information of these wavelengths is multiplexed in the wavelength multiplexing circuit 209 and output to the ultra high speed network.

FIG. 3 shows detailed blocks of the Drop circuit. An equivalent of the Drop circuit 202 in FIG. 2 is the Drop circuit 300 in FIG. Drop circuit 300
Exist for the number of wavelengths multiplexed on the ultra-high-speed network. In this example, since m wavelengths are multiplexed, there are m Drop circuits 300. Drop circuit 300
From the destination information described in the header of the transfer information, the Drop / Table 304 refers to Drop-Table 304 to determine whether to transfer (Drop) to the local network or transfer to the ultra-high speed network (Through).
It is determined by the rough select circuit 301. The information that has received the Drop determination makes effective use of the n × n band provided at the input point of the local network, and thus performs load distribution for n channels. The load distribution circuit 302 performs this load distribution. After the load distribution, the buffer 303 before transferring to the band sharing circuit 305 for band sharing the information separated into n channels by the information transferred in m kinds of wavelengths
Is provided so that the competition that occurs when sharing the bandwidth can be absorbed.

FIG. 4 shows a detailed block diagram of the Add circuit. An equivalent circuit of the Add circuit 208 in FIG. 2 is shown in FIG.
The Add circuit 400 in FIG. In the Add circuit 400,
Transfer to the ultra-high speed network by the judgment of the Drop circuit (Th
It has a function of controlling the competition between the information determined as “root” and the information transferred from the local network, and transferring to the ultra-high speed network. In the ultra-high speed network, the line valid setting information 402 in which whether transfer at the corresponding wavelength is possible is set and the information is referred to, and the Drop circuit judges and transfers to the ultra-high speed network (Through).
A availability determination circuit 403 is provided to determine whether the information determined to be transferred is being transferred and to determine whether the information from the local network side can be transferred.

The availability determining circuit 403 also controls the transfer of the information determined to be transferred (Through) to the ultra-high speed network while the information is being transferred from the local network. At this time, the buffer 404 is provided to temporarily hold the transfer information. It is the Add / Through selection circuit that selects whether to output the data to the ultra-high-speed network as the transfer data from the ultra-high-speed network or the transfer data from the local network according to the result of the determination by the availability determination circuit 403. 401
Is.

Transfer information from the local network is
The output line selection circuit 40 is stored in the temporary buffer 406.
At 5, the available wavelength at the present time is determined from the availability information determined by the availability determination circuit 403 from the Add circuit 400 for each wavelength, and the wavelength of the output destination is determined. At this time, in order to average the information flowing through each wavelength as much as possible, the load is dispersed and the wavelength to be used is determined in order. Description of Operation of Embodiment FIG. 1 shows an example of the ultra-high speed network of the present invention. The information flowing on the network in FIG. 1 is the IPv4 packet shown in FIG. The user terminal 105 is connected to the local network 104, and has a network interface 103 for matching the interface between the local network 104 and the ultra-high speed network 101.
Through the connection to the Add / Drop 102, the information transfer is realized.

The local network 104 to which the user terminal 105 is connected is a network currently used for IPv4 packet transfer, and more specifically, SDH for transferring IP packets by packet over SONET (PoS). A network or Ethernet is possible.

There is a network interface 103 as a conversion unit for connecting these different interfaces to an ultra high speed network. This network interface 103 absorbs the interface difference between the networks such as protocol conversion, and then adds / Dr
IP to the ultra-high speed network 101 via op102
The packet is forwarded.

On the other hand, the transfer to the local network 104 is judged by Add / Drop 102, the destination information of the IPv4 packet flowing on the ultra-high speed network 101 is read, and if it is the corresponding local network, the local network side is sent. Transfer to (Dro
p). In this way, the ultra high speed network 10
The IPv4 packet is forwarded via 1. Here, the ultra-high speed network 101 is a wavelength division multiplexing (WDM) system.
As an example, a case will be described below in which a 128 Gbps optical interface is multiplexed with 128 waves and the local network has eight 2.4 Gbps optical interfaces as an example.

First, the operation principle will be described with reference to the configuration diagram of the Add / Drop section shown in FIG. As mentioned above, the wavelength multiplexed in the ultra high speed network 101 is 128.
Because of the wave, the number of wavelengths separated by the wavelength separation circuit 201 is 1
28 and λ1 to λ128. In addition, the packet switch 2 provided on the local network 104 side
06 has a capacity of 2.4 Gbps per line of 8 × 8.

The information λ1 to λ128 for each wavelength separated by the wavelength separation circuit 201 is the D provided for each.
Each is input to the rop circuit 202, and it is determined whether to transfer to the local network 104 side or to the ultra high speed network 101 side.

When it is determined to transfer to the local network 104 side, the load is distributed to the number of input ports of the packet switch 205 provided in the local network 104, and in this example, it is distributed to 8 ports of 2.4 Gbps, In the band sharing circuit 203, information for the number of wavelengths is band-shared. In this example, 128 waves of information are band-shared. In simple calculation, the information transfer capacity on the ultra high speed network 101 side is 128 wavelengths × 2.4 G
bps, at the input point of the local network 104,
It becomes 8 Line × 2.4 Gbps, and since the input side has a capacity of 16 times, it overflows at peak time.

However, the amount of information transferred to the local network 104 side is relatively small compared to the information flowing on the ultra-high speed network, and the local network 10
Even if information exceeding the capacity of the packet switch 205 provided at the input point is made to flow into the four side, it will eventually overflow because it cannot be processed in the local network.
In actual operation, it is unlikely that the peak value will always continue to occur, and even if a transient overflow occurs, it will not cause a system problem.

Further, since the information is transferred by distributing the loads of the eight Lines before the input to the band sharing circuit 203, the load at the local network input point at the peak time is dispersed and the overflow is avoided. The method is adopted. In the local network and the interface at the output point of the band sharing circuit 203, a network interface 204 having a function of performing frame conversion and terminating depending on the transfer method of the connected local network is provided.

This network interface 204
Through 8x8 (2.4 Gbps / Lin deployed at the local network input point after frame conversion via
e) connected to the packet switch 205.

On the other hand, the information from the local network 104 to the ultra high-speed network 101 side is, first, 8 × 8 which is arranged at the output point of the local network 104.
(2.4 Gbps / Line) packet switch 20
It is switched at 5 and output. It is connected to the output line selection circuit 207 of the ultra high-speed network 101 via the network interface 204 to match the interfaces between the networks.

In the output line selection circuit 207, the transfer state on the ultra high speed network is monitored from the Add circuit 208 provided for each wavelength, and the local network 104 is connected.
The information output from the above is considered so that the output is averaged for each wavelength line, and the transferable state is monitored and output to the available line.

At the output point of the local network 104, these pieces of information may be transferred to any of 128 lines of 2.4 Gbps in 8 lines of 2.4 Gbps. At the output point, contention control with the information passing through the ultra high speed network 101 is performed by the Add circuit 208, and the transfer information of each wavelength is wavelength-multiplexed and then output to the ultra high speed network.

In the example of FIG. 2, the wavelength separation circuit 201 and Dr
O / E (optical / electrical conversion) 210 between the op circuit 202
Between the Add circuit 208 and the wavelength multiplexing circuit 209.
An O (electrical / optical conversion) 211 is provided, and the processing during this period is currently composed of an electric circuit that can be realized.

Further detailed operation of the Drop circuit will be described with reference to FIG. FIG. 3 is a configuration diagram of the Drop side of the present invention.

As described above, the Drop circuit is a device block that determines whether to transfer information to the local switch side or the ultra-high speed side. At the input point, Dr
The op / Through selection circuit 301 reads the destination information from the transferred information, and drops the Drop-Table.
Go to refer to 304. In this example, since the transferred information is an IPv4 packet, the referenced destination information is contained in the 17th byte to the 20th byte as shown in the IPv4 packet structure in FIG. This destination information is extracted and referred to the Drop-Table 304, and if applicable, is transferred to the local network side.

Further, in order to simplify the destination determination, an identification address unique to the local network is assigned to
By labeling and adding this identification address to the v4 packet, a method of determining the destination at a higher speed can be adopted.
In addition, by adding transmission source information to the destination, it is possible to incorporate a function of determining a packet having no destination on the ring.

That is, when the address of the source local network is detected again in the source network, it indicates that the transmitted packet was not accepted by any local network. If it continues to flow on the network, there arises a problem that useless packets consume bandwidth on the network. To deal with this problem, discarding these packets also has the effect of preventing abnormal packets from continuing to flow on the network.

If nothing is set in the Drop-Table 304, the pass-through mode is set and there is no transfer to the local network side. Therefore, when it is desired to disconnect the local network from the ultra high speed network, it can be realized by setting nothing in this Drop-Table 304. When the information flowing through the Drop / Through selection circuit 301 has a capacity of 2.4 Gbps and is determined to be transferred to the local network side,
It is input to the load distribution circuit 302.

Information having a maximum input capacity of 2.4 Gbps and having a maximum input capacity of 2.4 Gbps, which is load-balanced according to the number of Lines of the packet switch arranged at the input point of the local network, is distributed to 8 Lines having a maximum transfer capacity of 2.4 Gbps.
At this time, packets belonging to the same IP flow have the same L
By allocating to the ine, the context of the packet is maintained and the packet is transferred. This distribution can be realized by a method of determining a route from a value obtained by using a hash function from the destination information of the IP. In the case of different destinations, different Lines are randomly selected to some extent, and in the case of the same destination, , Same L
ine is selected.

After the load is distributed by the load distribution circuit 302, information is temporarily stored in the buffer 303 and then transferred to the band sharing circuit 305. This band sharing circuit 305 is
It corresponds to the band sharing circuit 203 in FIG. The reading from the buffer 303 is performed under the control of the band sharing circuit 305, receives a determination signal of whether the band sharing circuit 305 can transfer the data, and transfers the signal when the reading is possible. Transfer Lin
There is a case where e cannot be transferred in a busy state, so a buffer 303 is provided to handle this.

The band sharing circuit 305 can be implemented in various ways, but the basic function in this example is to load-balance 128 lines into eight lines and then aggregate them into eight lines.

The information in which the load is distributed for each wavelength is distributed to eight lines. The names of the outputs are λ1-ch1 and λ1-ch.
2, ... λ1-ch8, λ2-ch1, λ2-ch2,
..... lambda.2-ch8, ..., .lamda.128-ch1, and .lamda.128
-Ch2, ... λ128-ch8, λ1-c
Line h1 and λ2-ch1 ··· λ128-ch1
1, λ1-ch2 and λ2-ch2 ... λ128-c
h2 to Line2, λ1-ch8 and λ2-
ch8 ... Means that .lamda.128-ch8 is integrated into Line8. The process of selecting one from 128 may be performed for each line. Therefore, it is sufficient to manage which line of 128 wavelength division multiplex information is being transferred, and to realize a function of transferring the information when other lines are not transferring information.

FIG. 6 shows an example of a method of realizing the band sharing circuit. Further, the operation timing is shown in the band sharing circuit timing chart of FIG. It is a band sharing circuit block diagram of this invention. FIG. 7 is a time chart of the band sharing circuit.

Data of each wavelength is converted to λ1_data to λ12.
8_data, and when transfer information is accumulated in the buffer 303 in FIG. 3, a transfer request is sent out.

This request signal is sent to λ1_req to λ128_.
Let req. When information transfer is accepted by the band sharing circuit, acceptance permission signals λ1_act to λ128_a.
Output ct. Bandwidth sharing is performed by these controls.
In FIG. 6, when the information to be transferred is generated, the λ_req signal is generated.

In the example of the time chart of FIG. 7, the request of λ1 is generated at the time of. If this request does not conflict with the transfer of information of another wavelength in the acceptance order determination circuit 603 in FIG. 6, it is immediately accepted, and if there is a conflict, the acceptance order is taken into consideration, and there is a request at an early time. Accept the reception from the wavelength information.

In the time chart of FIG. 7, λ2 is accepted at the time of, and the requests for λ2 and λ3 are made at this time, but the request is made at the time of λ2 and the time of λ3. , As a result, λ that was requested earlier in terms of time
Two requests have been accepted. This control is performed by the acceptance order determination circuit 603 in FIG.

After determining the context of the order of acceptance, it is determined whether or not an information transfer request for another wavelength has been made by λx for each wavelength.
After the determination by and (x: 1 to 128) 602, when information of another wavelength is not transferred, λx_act (x: 1
~ 128) is activated and acceptance is permitted. The gate 601 is opened and the output path as Line_data is established in the route of the wavelength information for which the reception is permitted.

At the same time, reading from the buffer 303 in FIG. 3 is started and information is transferred. When the transfer is completed, λx_req (x: 1 to 128) is turned off to open the bus, and at the same time, the information of another wavelength for which the transfer is requested is accepted. Line sharing circuit that operates as above
Several minutes, in this example, eight circuits are provided and connected to the local network.

In order to realize the band sharing circuit, the CSMA / CD method used in Ethernet is used.
It can also be realized by means of transferring a book line by a method of sharing.

Next, the detailed operation of the Add circuit will be described with reference to FIG.
Using. The information from the local network 104 is accommodated in the buffer 406 in FIG. 4 after absorbing the interface difference between the networks in the network interface 204 in FIG.

In the output line selection circuit 405, transferable wavelengths are searched by referring to the transfer permission signal from the Add circuit 400 provided for each wavelength. In addition, the destination stored in the 17th to 20th bytes of the packet to be transferred is load-balanced, and one packet having the same destination is selected from 128 wavelengths so as to be assigned to the same wavelength. .

This load balancing method includes a method of randomly selecting a line from the destination information by using a hash function and transferring the line. Since the result obtained by the same calculation method is used,
The information of the same destination can select the same wavelength, and the information of different destinations selects random wavelengths to distribute the load. This can be realized by the same idea as the load balancing method described in the operation of the Drop circuit 300 in FIG. If the transfer permission signal from the load-balanced output destination Add circuit 400 is in the transfer permission state, the transfer state is entered, and reading from the buffer 406 is started.

If the transfer is not permitted, a waiting state is entered. Add circuit for λx for each wavelength (x: 1 to 12
8) 400 is not transferred to the local network,
A buffer 404 for temporarily storing information passing through to the ultra-high speed network and an Add / Through selection circuit 40 for selecting information transferred from the local network side and information passing through to the ultra-high speed network.
1, and line availability setting information 402 and an availability determining circuit 403 that controls transfer information based on the transfer status. The line valid setting information 402 is for setting whether the corresponding wavelength is valid or invalid. When it is set invalid, information transfer at that wavelength cannot be performed. It is possible to determine whether the information from the local network side can be transferred from the setting information and the state of the buffer 404 that temporarily stores the information passing through the ultra high speed network, and output the transfer permission signal. The circuit 403.

When the line valid setting information 402 is invalid, the availability determining circuit 403 notifies the output selecting circuit 405 that the line is unavailable, and the output selecting circuit 405 displays the line. Control to exclude from the target of load balancing.

Further, in the availability determining circuit 403, when the information that passes through the ultra-high speed network is input during the information transfer from the local network side, the reading of the buffer 404 is stopped and the information from the local network side is transmitted. It also controls the output to wait until the transfer is completed.

The information thus output passes through the E / O (electrical / optical conversion) 211 in FIG. 2 and is converted into optical information of a designated wavelength, and then passes through the wavelength multiplexing circuit 209 to the ultra-high speed network. Is output to. Other Embodiments of the Invention Next , other embodiments of the present invention will be described.

In FIG. 2, assuming that the wavelengths transferred to the local network side are limited to 8 wavelengths, in this case, the information transferred to the local network side is 2.4 Gbp.
There are eight s, which are matched with the input capacity of the packet switch at the input point of the local network.

A method constructed under such conditions is shown in FIG. Further, FIG. 9 shows a network configuration diagram in which Add / Drop having a function of transferring to such a local network is provided. In FIG. 9, each Add / Drop9
In 02, the wavelength to be transferred to the local network side is limited, and for example, Add / Drop λ1 to λ8 (902-
In A), only wavelengths λ1 to λ8 are transferred to the local network side, and Add / Drop λ9 to λ16 (90
In 2-B), wavelengths of only λ9 to λ16 are transferred to the local network side.

Therefore, the transfer destination local network is determined by the wavelength, and the output line selection circuit 807 in FIG. 8 is a circuit for selecting the line of the wavelength assigned to the transfer destination local network. By adopting such a configuration, the band sharing circuit 203 shown in FIG. 2 becomes unnecessary. In addition, the Drop circuit 802 of FIG.
Is the Drop / T in the Drop circuit 300 in FIG.
Hough select circuit 301 and Drop-Table3
It can be realized with a circuit configuration of only 04.

By thus assigning a wavelength to each local network and managing the destinations by wavelength, information for the same local network is transferred for each wavelength, and flows on one line. Compared to the case where the destinations have different information, it is easier to manage on the network and traffic is easier to manage.

As described above, according to the present invention, when constructing an ultrahigh-speed network realized by the wavelength division multiplexing method, the network is configured in a ring shape, rather than a large-capacity crossbar switch, and a simple structure is adopted. Add / Dro
This is an ultra-high-speed network construction method that simplifies the configuration and provides more flexible network expandability by using the load distribution technology of the p-circuit and the bus.

As described above, according to the present invention, in the ultra high-speed network connected in a ring by the wavelength division multiplexing system shown in FIG. 1, the connection with the local network close to the subscriber is connected by the Add / Drop circuit. It is applied in a network that realizes and has the following features.

First, in Add / Drop at the time of taking in the local network, the header of the packet is checked to determine whether to take it in. By determining by referring to the destination described in the header of the conventional packet, it can be realized without constructing a new frame.

Secondly, at the entrance to the local network, a plurality of lines are prepared and the load is distributed in order to effectively use the band of the lines. By performing load balancing, there is a feature that it is possible to absorb to some extent the difference in transfer rate when an ultra-high-speed network with a high transfer rate takes in a local network with a low transfer rate compared to an ultra-high-speed network. The load distribution is a distribution number corresponding to the Line number of the packet switch at the intake port to the local network.

Since the above dispersion is performed corresponding to one wavelength of the wavelength-multiplexed wavelengths, each Lin of the packet switch
In the case of e, the information of the lines corresponding to the number of wavelength-multiplexed wavelengths after the load distribution is shared. It is characterized in that the band sharing is performed by the band sharing circuit.

Thirdly, a packet switch is installed at the entrance to the local network, but 2.4
It is composed of an existing packet switch such as G 8 × 8. The switch capacity here is the capacity of the packet switch determined by the maximum value of the capacity handled by the local network. Therefore, the amount of information that can be taken into the local network is limited to this packet switch capacity. In other words, at the connection point from the ultra-high-speed network to the local network, the maximum bandwidth that the ultra-high-speed network has is not necessary, and the maximum bandwidth that the local network can handle can be reduced.

Fourth, in this ultrahigh-speed network construction method, the connection with the local network is simply added / added.
It is connected by Drop, and the number of connectable local networks can be increased by increasing the number of Add / Drop points. Also, by increasing the number of wavelengths to be wavelength-multiplexed, the bandwidth of the network can be increased, and as a result, the amount of information that can be processed by the network can be increased. As described above, this ultra-high-speed network construction method has excellent expandability, and when increasing the capacity of the network, the
It has the feature that the network capacity can be easily expanded by changing the settings at the Add / Drop points and increasing the types of wavelengths to be transmitted, instead of replacing the hardware.

Fifth, in the method of the present invention, each wavelength can be assigned to each local network, and a method of assigning a wavelength to each destination and managing the destination according to the wavelength can also be adopted. By adopting such a method, since information for the same local network is sent for each wavelength, management on the network is easier and traffic management is easier than when the information flowing on one line is a different destination. There is a feature that makes it easy.

[0076]

According to the present invention, it is necessary to improve the hardware processing speed as the bandwidth to be handled increases in the network. In the present invention, the network is constructed and transferred using the wavelength division multiplexing (WDM) technique. Basically, even if the amount of information increases, it can be dealt with by increasing the number of wavelengths that are wavelength-multiplexed. Therefore, the processing upper limit per line used in the current technology can be about 2.4 Gbps.

In the present invention, in constructing an ultra-high speed network, wavelength-multiplexed (WDM) lines are used to connect in a ring shape, and Add / Drop is provided at the point of connection to the local network to connect the network. The overall configuration can be simplified.

In addition, in anticipation of future expansion, the Ad may be previously set at a place where it may be connected to the local network.
Deploy d / Drop, set it to the transit state for the time being, and at the time of increasing the connection of the local network,
It is highly expandable because it can be operated by connecting to the added local network by setting the transfer settings.

Further, in the mesh-shaped network, n-1 lines are taken in at the points connected to the local network with respect to the number n of connected local networks, and one of the local networks is added. As a result, it is necessary to add n-1 lines. However, in the present invention, since the Add / Drop configuration is adopted at the point connected to the ultra high speed network, only the number of lines connected to the local network needs to be connected, and the expansion is relatively easy. You can do it.

The network of the present invention uses wavelength division multiplexing (WD).
Since it is connected in a ring shape by M), it is possible to cope with the increase in the amount of information by increasing the number of wavelengths to be multiplexed.
Furthermore, the bandwidth can be shared up to the maximum capacity of the line, and non-blocking switching can be performed as in a mesh-shaped network.

Further, by assigning a wavelength to each local network and assigning a wavelength to each destination, it is possible to transfer between networks, and management on the network becomes clear.

Furthermore, by providing a network interface that absorbs the difference between the interface of the local network and that of the ultra-high speed network, a network having different interfaces can be created.
Can be connected via a common ultra-high speed network.

As described above, according to the present invention, unlike the case where the network is configured by the crossbar switch even if the number of connected networks increases, the delay does not increase, and the present technology can realize the speed. It can take various configurations.

[Brief description of drawings]

FIG. 1 is a block diagram of an ultra-high speed network according to the present invention.

FIG. 2 is a configuration diagram of an Add / Drop unit of the present invention.

FIG. 3 is a configuration diagram of a Drop side of the present invention.

FIG. 4 is a configuration diagram of an Add side of the present invention.

FIG. 5 is an IPv4 packet configuration diagram.

FIG. 6 is a block diagram of a band sharing circuit of the present invention.

FIG. 7 is a band sharing circuit time chart.

FIG. 8 is a second configuration diagram of the Add / Drop unit of the present invention.

FIG. 9 is a second configuration diagram of the ultra-high speed network of the present invention.

FIG. 10 is a block diagram of a mesh type ultra high speed network.

[Explanation of Codes] 101, 901, 1001 Ultra High Speed Network (WD
M network) 102,902 Add / Drop 103,903,1003 Network interface 104,904,1004 Local network 105,905,1005 User terminal 201 Wavelength separation circuit 202 Drop circuit 203 Band sharing circuit 204 Network interface 205,206,805 , 806 n × n packet switch 207 Output line selection circuit 208 Add circuit 209 Wavelength multiplexing circuit 210, 810 O / E 211, 811 E / O 300 Drop circuit 301 for λn Drop / Through selection circuit 302 Load distribution circuit 303 Buffer 304 Drop -Table 305 Band sharing circuit 400 Add circuit 401 for λn Add / Through selection circuit 402 Line valid setting information 403 Availability judgment times 404,406 Buffer 405 outputs the line selection circuit 600 bandwidth sharing circuit 601 gate 602 lambda] n for And 603 accepts order determination circuit 801 wavelength demultiplexing circuit 802 Drop circuit 804 network interface 807 outputs the line selection circuit 808 Add circuit 809 Wavelength multiplexing circuit

─────────────────────────────────────────────────── --Continued from the front page (56) Reference JP-A-56-75735 (JP, A) JP-A-3-258053 (JP, A) JP-A-4-2238 (JP, A) JP-A-11- 331224 (JP, A) JP 2000-13329 (JP, A) JP 2000-165425 (JP, A) JP 2000-295262 (JP, A) JP 2001-16206 (JP, A) (58) Investigation Areas (Int.Cl. ⁷ , DB name) H04L 12/42

Claims (9)

(57) [Claims] 1. A ring-shaped WDM network realized by a wavelength multiplexing system, and the WDM network and A
In an ultra high-speed network including a plurality of local networks that accommodate a plurality of user terminals and are connected by a dd / drop device, the add / drop device separates m wavelength signals input from the WDM network by wavelength. A wavelength demultiplexing circuit, and a drop circuit for each wavelength that determines whether to transfer the demultiplexed wavelength information to the local network side or to directly exit to the WDM network side via the Add circuit,
An ultra-high-speed network construction method comprising: a band sharing circuit that shares the band determined by the Drop circuit with information for m wavelengths and outputs the information to a local network. 2. The Drop circuit for each wavelength is the Add
/ Drop device is provided with means for separating the input information for performing the Drop into the number of input ports of the n × n packet switch provided at the connection point with the local network and inputting into the band sharing circuit. The ultra-high-speed network construction method according to claim 1. 3. The Add / Drop device determines an output line according to a transfer destination of a signal received from a local network via the n × n packet switch, and transfers the signal to an Add circuit at a subsequent stage. The line selection circuit and the Add circuit perform competition control between information that passes through the local network without being dropped and transfer information transmitted from the output network selection circuit from the local network, and the wavelength specified in the WDM network is controlled. The ultra-high-speed network construction method according to claim 2, further comprising means for performing transfer by. 4. The Drop circuit stores D in advance from the destination information described in the header part of the transfer information.
A Drop / Through selection circuit that determines whether to transfer to the local network or to the ultra-high speed network by referring to the drop-table, and a Drop / Through selection circuit.
In order to effectively use the bandwidth of the n × n switch arranged at the input point of the local network for the information determined by p, a load balancing circuit that performs load balancing for n channels, and a load balancing circuit after the load balancing in the load balancing circuit , A configuration in which a buffer is provided before the information separated into n channels is transferred to a band sharing circuit for band sharing by the information transferred at m types of wavelengths, and the competition generated when band sharing is absorbed The ultra-high-speed network construction method according to claim 3, further comprising: 5. The information added to the Add circuit is judged to be transferred to the ultra-high speed network by the judgment of the Drop circuit and the information transferred from the local network and stored in the buffer provided in the preceding stage of the output line selection circuit. Means for controlling contention control, line valid setting information for setting whether or not transfer at a corresponding wavelength is possible in the ultra high speed network, and transfer to the ultra high speed network when the Drop circuit judges with reference to the line valid setting information. The ultra-high-speed network construction method according to claim 4, further comprising a availability determination circuit that determines whether the information determined to be transferred is being transmitted and determines whether the information from the local network side can be transferred. 6. The availability determining circuit stops transfer of information determined to be transferred to the ultra-high speed network during transfer of information from the local network, and temporarily holds the transfer information for which transfer has been stopped. And an Add / Through selection circuit for selecting whether to output data to the ultra-high-speed network as transfer data from the ultra-high-speed network or transfer data from the local network according to the result of the determination by the availability determination circuit. The ultra-high speed network construction method according to claim 5. 7. The output line selection circuit acquires a transferable state on an ultra-high speed network from an Add circuit provided for each wavelength, and outputs information output from the local network to a line of each wavelength. 7. The ultra-high-speed network construction method according to claim 6, further comprising means for averaging the outputs and outputting them to a transferable line. 8. The Drop circuit includes destination information, source information included in transfer information from the WDM network,
5. The ultra-high speed network according to claim 4, further comprising means for determining Drop / passage / discard of the transfer information to the local network by referring to label information corresponding to an identification address unique to the local network. Construction method. 9. A ring-shaped WDM network realized by a wavelength multiplexing system, and the WDM network,
An Add / Drop device for connecting a plurality of local networks accommodating a plurality of user terminals, wherein the Add / Drop device includes a header of a packet when the packet transferred from the WDM network is taken into the local network. And a determination means for determining whether or not to take in, and a dispersion number corresponding to the Line number of the packet switch arranged at the connection point of the local network, corresponding to one wavelength of the wavelength-multiplexed wavelengths. An ultra-high-speed network construction characterized by having means for performing load distribution and band sharing means for sharing line information for each number of wavelength-multiplexed wavelengths after load distribution in each line of the packet switch apparatus.