JPH1117695A - Atm communication network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To economically secure the transfer route of cells for transferring general information and the transfer route of the cells for transferring control information inside an optical wavelength routing network, capable of flexibly coping with the increase in traffic and to effectively utilize network resources by setting the output route of the optical cell, corresponding to the wavelength of the inputted optical cell. SOLUTION: In access control parts 1-1-1-4, the kinds of information included in the cells arriving from LANs 2-1-2-4 are judged. The cell is converted into the optical cell of a determined wavelength, corresponding to the information kind and the destination and is transferred to a center network 50. The center network 50 is provided with optical wavelength cross-connection devices 3-1-3-4, for which the output route of the optical cell is set corresponding to the wavelength of the inputted optical cell. Then, in an LAN of a non-destination which receives the optical cell from the center network 50 transfers the optical cell to a route other than the route from which the optical cell arrived. Thus, the optical cell can finally reach a target destination.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ATM (Asynchronou).
s Transfer Mode) Used for communication. The present invention provides a plurality of A
Local area network by TM (hereinafter referred to as LAN)
It is suitable for use in large-scale ATM communication networks including In particular, the present invention relates to a traffic control technique in communication between LANs by ATM.

[0002]

2. Description of the Related Art In an ATM communication network, a large-scale ATM communication network is constructed by interconnecting LANs using a plurality of ATMs. This conventional example will be described with reference to FIG. FIG. 6 is a diagram showing a conventional ATM communication network.

In a conventional ATM communication network, for example, LAN
When the communication terminal 10 connected to 2-1 transfers a cell to the communication terminal 20, first, the communication terminal 20 as a destination is searched in the LAN 2-1. Is recognized, then LA
The cell is transferred to N2-2. Here, the communication terminal 20 as the destination is searched, and if it is recognized that the communication terminal 20 does not exist on the LAN 2-2, the cell is transferred to the LAN 2-3. By repeating such a procedure, the cell finally arrives at the communication terminal 20 connected to the LAN 2-4. If such a flow of cells occurs constantly, it is dealt with by providing a dedicated line 30.

[0004] In addition, the bridges 40 to 42 connecting the LANs 2-1 to 2-4 are connected to the cells that frequently pass through the bridges 40 to 42. Since it is possible to learn whether or not the cell exists, the cell transfer can be performed smoothly.

[0005]

SUMMARY OF THE INVENTION Such a conventional AT
In the M communication network, as the scale of the LANs 2-1 to 2-4 increases, the amount of traffic passing through the bridges 40 to 42 also increases.

For this purpose, it is necessary to provide a dedicated line 30 or to increase the line capacity of the bridges 40 to 42.
If the size of the is large, it will not be able to cope.

Further, the traffic distribution of the bridges 40 to 42 is not always distributed to the respective bridges 40 to 42 on average. -3, the traffic is biased in order from the bridge 42 closer to the LAN 2-4 to the bridge 41 and the bridge 40. Therefore, the capacity of each of the bridges 40-42 must be able to cope with the maximum traffic that can occur in the entire ATM communication network.

As described above, in the conventional ATM communication network, it is difficult to flexibly cope with traffic expected to increase in the future.

The applicant of the present application has filed a prior application (Japanese Patent Application No. 9-1496).
No. 14, unpublished at the time of filing the present application) proposed an ATM communication network using an optical wavelength routing network. The ATM communication network using the optical wavelength routing network is provided with a center network accommodating each LAN in a star shape so as to flexibly cope with expansion of each LAN. By using a fixed optical wavelength routing network for the center network, a large-scale ATM communication network can be easily realized without using a complicated device such as a center server.

In the ATM communication network using the optical wavelength routing network of the prior application, only the transfer path of cells for transferring general information is set, and the transfer path of control information (hereinafter referred to as control line) is set. Did not mention.

The present invention has been made in view of such a background, and has a cell transfer path and control for transferring general information in an optical wavelength routing network which can flexibly cope with an increase in traffic. It is an object of the present invention to provide an ATM communication network capable of economically securing a cell transfer path for transferring information and effectively using network resources. SUMMARY OF THE INVENTION An object of the present invention is to provide an ATM communication network capable of easily configuring a large-scale and large-capacity network.

[0012]

SUMMARY OF THE INVENTION The most important aspect of the present invention is to provide an optical wavelength routing network for relaying traffic between all LANs by ATM, and to have only two wavelengths for control information transfer in each LAN. Features.

[0013] The conventional technique is to pass traffic between all LANs through an optical wavelength routing network,
The traffic between them is distributed in a distributed manner, the optical wavelength routing network is semi-fixed, and there are two wavelengths for control information transfer, and this wavelength is always connected to two independent LANs. Is different.

That is, the present invention is an ATM communication network comprising a plurality of local area networks based on ATM and a center network for transferring cells between the plurality of local area networks. . A feature of the present invention is that, in the cell, a cell including general information and a cell including control information are mixed, and a means for determining an information type included in a cell coming from the local area network, Means for converting a cell into an optical cell having a wavelength determined according to its information type and its destination, and transferring the cell into the center network. An output route is provided with an optical wavelength routing means. In the center network, it is preferable that an output route of the optical cell is fixedly set.

As a result, each LAN is connected to the center network in a star configuration, so that it is possible to avoid a decrease in throughput due to the passage of traffic. In the present invention, by using the optical wavelength routing means in the center network, there is no need to provide a complicated device such as a center server. Therefore, as compared to the case where a complicated device such as a center server is provided, the maintenance and inspection of the center network is not troublesome, and the probability of occurrence of a failure or the like is low.

The cell may be an optical cell already at the LAN stage, or may be an electric signal cell at the LAN stage and converted into an optical cell by the transfer means.

According to the present invention, a path for transferring general information and a path for transferring control information can be individually provided.

Preferably, the transfer means includes a table in which a local area network as a destination for each type of information and wavelength information for transferring to the local area network are recorded.

Preferably, two control information transfer paths are set in each of the plurality of local area networks, and two different wavelengths are assigned to the two transfer paths.

It is preferable that one control information transfer path is set between any two local area networks of the plurality of local area networks.

As a result, the control line can be configured with a small number of allocated wavelengths and a small number of routes, so that network resources can be effectively used.

A configuration may be adopted in which two wavelengths are selected in common for the plurality of local area networks, and these two wavelengths are alternately assigned each time a control information transfer path passes through the local area network.

According to this, since the control line can be constituted by the required minimum number of allocated wavelengths, network resources can be effectively used.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing the overall configuration of an embodiment of the present invention. FIG. 2 is a diagram showing a table of the access control unit. FIG. 3 is a diagram illustrating a main block configuration of the access control unit.

The present invention relates to an ATM communication network,
This is an ATM communication network including -1 to 2-4 and a center network 50 for transferring cells between the LANs 2-1 to 2-4.

Here, a feature of the present invention is that cells including general information and cells including control information are mixed in the cells, and the access control units 1-1 to 1-4 are provided with LAN2
An information type determination unit 13 as means for determining the type of information included in the cell arriving from -1 to 2-4, and converting the cell into an optical cell having a wavelength determined according to the information type and its destination, and An optical cell generator 11 as means for transferring the data into the network 50; and the center network 50 comprises an optical cell as an optical wavelength routing means in which the output route of the optical cell is set according to the wavelength of the input optical cell. The wavelength cross-connect devices 3-1 to 3-4 are provided. In the center network 50, the output route of the optical cell is fixedly set.

The access control units 1-1 to 1-4 record destination LANs 2-1 to 2-4 and wavelength information to be transferred to the LANs 2-1 to 2-4 for each information type. Table 12 is included.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In an ATM communication network according to an embodiment of the present invention, LAN2
The transfer of the optical cell between -1 and 2-4 is performed by LAN 2-1 to 2-
4 access control units 1-1 to 1-4 respectively
Is processed by For example, LAN2-1 to LAN2
-2 is automatically transferred to the LAN 2-2 via the access control unit 1-2 by selecting the wavelength λ1 by the access control unit 1-1.

The center network 50 is a passive network, and the transfer is fixedly determined. However, it is possible to rearrange the configuration of the network instead of real-time depending on the traffic volume and the situation.

As shown in FIG. 2, the transmission-side access control unit 1-i (i = 1 to 4) determines the destination LAN 2-j (j = 1 to 4) from the destination information of the optical cell. Or
However, j ≠ i) can be determined, and the optical cell can be transferred to the destination LAN 1-j by selecting the corresponding wavelength.

When transferring an optical cell from the LAN 2-1 to the LAN 2-4, the transmission of the optical cell from the LAN 2-1 to the LAN 2-4 is performed.
Although there is no direct wavelength path to 2-4, in this case, for example, the optical cell is transferred to the LAN 2-3 using the wavelength λ2. In LAN 2-3, the optical cell is the LAN
Since this is not the destination in 2-3, this optical cell is transferred to the center network 50 again using the wavelength λ3. The optical cell having the wavelength λ3 is transferred to the LAN 2-2 via the access control unit 1-2. In the LAN 2-2, since the optical cell can be transferred to the LAN 2-4 by the wavelength λ2,
Can receive this optical cell. Alternatively, the optical cell is transferred from the LAN 2-1 to the LAN 2-2 using the wavelength λ1. In LAN2-2, the optical cell is the LAN
Since it is not the destination in 2-2, this optical cell is transferred to the center network 50 again using the wavelength λ2. In this way, the optical cell can be finally received at the target LAN 2-4.

As described above, when the desired wavelength path does not exist in the center network 50, the optical cell is transferred to any LAN having the wavelength path at random. In a LAN that is not the destination that has received the optical cell, the optical cell is transferred to a route other than the route from which the optical cell has arrived.
Thereby, the optical cell can finally reach the intended destination.

(First Embodiment) A first embodiment of the present invention will be described with reference to FIGS. 1 to 3 are as described above. FIG. 4 shows a plurality of LANs according to the first embodiment of the present invention.
FIG. 3 is a diagram showing the concept of a control line.

In the first embodiment of the present invention, as shown in FIG. 2, two control information transfer paths are set in each of the LANs 2-1 to 2-4, and two different transfer paths are set in the two transfer paths. Wavelengths are assigned. Furthermore, LAN2-
One transfer path is set for each of the control information transfer paths set between any two LANs 1-2.

As shown in FIG. 3, the control line has two wavelengths for each LAN, and these two wavelengths are independent LAs.
N. Here, independent means that no loop is formed,
This means that the path of the control line can be traced with one stroke. These control lines are used, for example, for communication with nodes in the LAN that do not have congestion or a working route, and for communicating information on failed nodes using this wavelength.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIG. FIG. 5 shows a plurality of Ls according to the second embodiment of the present invention.
FIG. 3 is a diagram illustrating the concept of an AN and its control lines. LAN 2-1
2 to 2-4, two control information transfer paths are respectively set, two different wavelengths are assigned to the two transfer paths, and a setting is made between any two of the LANs 2-1 to 2-4. Control information transfer paths are 1
A route is set, but in the second embodiment of the present invention, LAN2
Two wavelengths are commonly selected for -1 to 2-4, and these two wavelengths are alternately assigned each time the control information transfer path passes through the LAN.

As described above, only the wavelengths λ1 and λ2 are used for the control lines, and by repeating λ1, λ2, λ1,... Is composed of two wavelengths and can communicate with all nodes.

[0038]

As described above, according to the present invention,
It is possible to economically secure a cell transfer path for transferring general information and a cell transfer path for transferring control information in an ATM communication network using an optical wavelength routing network capable of flexibly coping with an increase in traffic. Effective use of network resources can be achieved. Further, a large-scale and large-capacity network can be easily configured.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a table of an access control unit.

FIG. 3 is a diagram showing a main block configuration of an access control unit.

FIG. 4 is a diagram showing the concept of a plurality of LANs and their control lines according to the first embodiment of the present invention.

FIG. 5 is a diagram showing the concept of a plurality of LANs and their control lines according to a second embodiment of the present invention.

FIG. 6 is a diagram showing a conventional ATM communication network.

[Explanation of symbols]

 1, 1-1 to 1-4 Access control unit 2-1 to 2-4 LAN 3-1 to 3-4 Optical wavelength cross-connect device 10, 20 Communication terminal 11 Optical cell generation unit 12 Table 13 Information type determination unit 30 Dedicated line 40-42 Bridge 50 Center network

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04Q 3/00 H04Q 11/04 C 11/04

Claims (6)

[Claims] 1. An ATM communication network comprising a plurality of local area networks based on ATM and a center network for transferring cells between the plurality of local area networks, wherein the cells include general information. Means for judging the type of information contained in a cell arriving from the local area network in which cells and cells containing control information are mixed, and an optical cell having a wavelength determined according to the information type and its destination. Means for converting the data into the center network and transferring the data into the center network, wherein the center network comprises an optical wavelength routing means in which an output route of the optical cell is set according to a wavelength of the input optical cell. ATM communication network. 2. The ATM communication network according to claim 1, wherein an output route of said optical cell is fixedly set in said center network. 3. The transfer means includes a local area network as a destination for each information type and a local area network.
2. The ATM communication network according to claim 1, further comprising a table in which wavelength information to be transferred to the area network is recorded. 4. The ATM according to claim 1, wherein two transfer paths for control information are set in each of said plurality of local area networks, and two different wavelengths are assigned to said two transfer paths. Communication network. 5. The ATM communication network according to claim 4, wherein one transfer path of control information is set between any two local area networks of the plurality of local area networks. 6. A method according to claim 1, wherein said plurality of local area networks are common to said plurality of local area networks.
One wavelength is selected and the control information transfer path is
The ATM communication network according to claim 4 or 5, wherein the two wavelengths are alternately assigned each time the light passes through the area network.