JP3690997B2 - Optical wavelength cut-through network and optical cross-connect equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is used in a network that forms a cut-through path using an optical wavelength as a label.
[0002]
[Prior art]
In a conventional MPLS (Multi-Protocol Label Switch) network, a high-traffic packet with a heavy processing load on a router is transferred without forming a cut-through path between a transmission line and an optical cross-connect device without going through the router. In recent years, a method of forming a cut-through path by using an optical wavelength instead of a label has come out, and this is called MPλS.
[0003]
FIG. 6 shows the configuration of a cut-through path in the conventional MPλS. 1 and 2 are routers, 3 is a packet distribution function, 4 and 5 are optical cross-connect devices, 6 is an optical wavelength multiplexing function, 7 is an optical wavelength separation function, 8 is a cut-through path, and 9 is a connection between the router 1 and the router 2 It is an optical transmission line.
[0004]
When a high traffic packet with a heavy processing load is detected in the router 1, the distribution function 3 is instructed not to pass through the routers 1 and 2 but through the cut-through path 8. The paths between the transmission side and the reception side are adjusted by the optical cross-connect devices 4 and 5 while being adjusted between the router 1 and the router 2. The optical wavelength is the same wavelength (indicated as λ1 in FIG. 6) from the transmission side to the reception side.
[0005]
Note that packets that do not have a heavy processing load on the routers 1 and 2 pass through the routers 1 and 2, but the router once converts the optical signal into an electrical signal, performs necessary processing, and then repeats the optical signal. Send it to the correct position. At this time, the light wavelength can be changed from λx to λy, for example, as shown in FIG.
[0006]
[Problems to be solved by the invention]
However, in MPλS, the optical wavelength used by one cut-through path in one network does not realize the optical wavelength conversion technology in the network, so the same optical wavelength is used from the transmission side to the final reception side. Will be used.
[0007]
Accordingly, since the optical wavelength used by one cut-through path cannot be used by other cut-through paths, paths can be configured only up to the number of optical wavelengths that can be used in the network, and it is difficult to expand the network scale.
[0008]
This problem can be solved by converting the optical wavelength by the optical cross-connect device every time it passes through the optical cross-connect device, but the technology has not been realized at present.
[0009]
The present invention has been carried out against such a background. By periodically switching the path, an optical path configuration having the number of optical wavelengths or more is possible, and a large-scale MPλS network can be realized. An object is to provide a wavelength cut-through network and an optical cross-connect device.
[0010]
[Means for Solving the Problems]
A first aspect of the present invention is an optical wavelength cut-through network including a plurality of N routers and a means for forming a cut-through path using an optical signal between the plurality of N routers.
[0011]
Here, a feature of the present invention is that the means for forming the cut-through path includes means for forming N cut-through paths starting from a plurality of N routers, each having a different light wavelength, and the cut-through path. Means for periodically and sequentially setting the end point of the through path to a plurality of N-1 routers excluding the router in which the start point of the cut-through path is set.
[0012]
Thus, by periodically switching the cut-through path, an optical wavelength cut-through path configuration equal to or greater than the number of optical wavelengths can be realized, and a large-scale MPλS network can be realized. For example, if a cut-through path having different optical wavelengths is to be formed between N routers, N ² -N types of optical wavelengths are required, and this becomes difficult to achieve when the value of N increases. Since a cut-through path can be formed between N routers by N types of optical wavelengths, even if the value of N increases, it is possible to cope with it.
[0013]
The second aspect of the present invention is an optical cross-connect device, and the feature of the present invention is that the optical wavelength cut-through network of the present invention is provided with a plurality of input terminals to which the plurality of cut-through paths are connected. And an output terminal, and means for connecting the input terminal and the output terminal on a one-to-one basis, wherein the means for connecting the output terminal to which the input terminal is connected to a different output terminal periodically and sequentially. There is a means to change.
[0014]
By using such an optical cross-connect device, the optical wavelength cut-through network of the present invention can be realized.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
An optical wavelength cut-through network and an optical cross-connect device according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a conceptual diagram of an optical wavelength cut-through network according to this embodiment. FIG. 2 is a configuration diagram of the optical cross-connect device of this embodiment. FIG. 3 is a diagram for explaining a switching pattern of the optical cross-connect device of the present embodiment. FIG. 4 is a diagram for explaining the switching timing of the optical cross-connect device of the present embodiment. FIG. 5 is a diagram for explaining the operation of the optical wavelength cut-through network of the present embodiment.
[0016]
As shown in FIG. 1, the first aspect of the present invention is that eight routers R1 to R8 connected to an optical XC (cross-connect) network and an optical wavelength cut between the eight routers R1 to R8. An optical wavelength cut-through network including a path setting device C that forms a through path. In FIG. 1, the path setting device C is illustrated at the center of the optical XC network, but the installation location is arbitrary and may be distributed at a plurality of locations in the network. Moreover, you may install in router R1-R8.
[0017]
Here, the feature of the present invention is that the path setting device C forms eight cut-through paths starting from the eight routers R1 to R8 with different optical wavelengths λ1 to λ8, respectively. Are periodically set to seven routers excluding the router in which the start point of the cut-through path is set.
[0018]
The second aspect of the present invention is an optical cross-connect device X shown in FIG. 2, and the feature of the present invention is that it is provided in the optical XC network shown in FIG. A plurality of input terminals L1 to L4 and output terminals L5 to L8 to which cut-through paths are connected, and a switching unit S that connects the input terminals L1 to L4 and the output terminals L5 to L8 on a one-to-one basis, As shown in FIG. 3, S is that the output terminals L <b> 5 to L <b> 8 to which the input terminals L <b> 1 to L <b> 4 are connected are sequentially changed to different output terminals periodically at regular time intervals as shown in FIG. 4. The optical cross-connect device X of the present invention sets an optical wavelength cut-through path between the routers R1 to R8 under the control of the path setting device C.
[0019]
In the following, embodiments of the present invention will be described in more detail.
[0020]
The optical cross-connect device X shown in FIG. 2 has 4 inputs × 4 outputs, an input optical transmission line to the optical cross-connect device X is connected to the input terminals L1 to L4, and an optical cross is connected to the output terminals L5 to L8. The output optical transmission lines of the connection device X are connected, P1-1 to P1-4 shown in FIG. 3 are connection paths in the switching pattern # 1 of the optical cross-connect device X, and P2-1 to P2-4 are optical cross-connects. The connection path in the switching pattern # 2 of the device X is shown.
[0021]
Switching pattern # 1 and switching pattern # 2 are periodically switched at regular time intervals as shown in FIG. That is, the input terminal L1 is connected to the output terminal L7 in the time zone of the switching pattern # 1. In the time slot | zone of switching pattern # 2, it has shown that the input terminal L1 is connected to the output terminal L6.
[0022]
Since switching of the optical cross-connect device X is performed in synchronization with the entire network, packets are not cut off during switching. One transmitting side uses one optical wavelength, but the receiving side needs to receive as many optical wavelengths as the other transmitting side. In the case of FIG. 3, since there are two switching patterns, it is only necessary to receive two optical wavelengths.
[0023]
The optical wavelength cut-through network of the present invention shown in FIG. 1 is provided with the optical cross-connect device X of the present invention shown in FIG. 2, and FIG. 5 shows the light of the connection path in the optical wavelength cut-through network of FIG. An example of wavelength and time switching is shown. λ1 to λ8 are optical wavelengths transmitted by the routers R1 to R8, and t1 to t7 are switching times of the optical cross-connect device X in the optical wavelength cut-through network.
[0024]
In FIG. 5, the router R1 transmits to the optical wavelength cut-through network at the optical wavelength λ1. In the optical wavelength cut-through network, the cut-through path is sequentially connected to the partner router such that the input time t1 from the router R1 is to the router R2 and the time t2 is to the router R3.
[0025]
The router R2 transmits to the optical wavelength cut-through network at the optical wavelength λ2. In the optical wavelength cut-through network, the cut-through path is sequentially connected to the partner router such that the input from the router R2 is time t1 to the router R3 and time t2 is the router R4.
[0026]
In general, in MPλS, in order to interconnect N routers, N ² −N optical wavelengths are required. However, in the present invention, the number of routers, that is, N optical wavelengths is sufficient.
[0027]
【The invention's effect】
As described above, according to the present invention, by switching the path periodically, it is possible to realize an optical path configuration equal to or more than the number of optical wavelengths and to realize a large-scale MPλS network.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of an optical wavelength cut-through network according to the present embodiment.
FIG. 2 is a configuration diagram of an optical cross-connect device according to the present embodiment.
FIG. 3 is a diagram for explaining a switching pattern of the optical cross-connect device according to the embodiment.
FIG. 4 is a diagram for explaining switching timing of the optical cross-connect device according to the embodiment.
FIG. 5 is a diagram for explaining the operation of the optical wavelength cut-through network of the present embodiment.
FIG. 6 is a diagram showing a configuration of a cut-through path in a conventional MPλS.
[Explanation of symbols]
1, 2, R1 to R8 Router 3 Packet distribution function 4, 5, X Optical cross-connect device 6 Optical wavelength multiplexing function 7 Optical wavelength separation function 8 Cut-through path 9 Optical transmission line C path connecting router 1 and router 2 Setting devices L1 to L4 Input terminals L5 to L8 Output terminals P1-1 to P1-4 Connection paths P2-1 to P2-4 in switching pattern # 1 Connection paths λ1 to λ8 in switching pattern # 2 Routers R1 to R8 Optical wavelengths t1 to t7 to be transmitted Switching time S Switching unit

Claims (2)

In an optical wavelength cut-through network comprising a plurality of N routers and means for forming a cut-through path by an optical signal between the plurality of N routers,
The means for forming the cut-through path is:
Means for forming N cut-through paths starting from a plurality of N routers, each having a different optical wavelength;
Means for periodically switching and setting the end point of the cut-through path to a plurality of N-1 routers excluding the router in which the start point of the cut-through path is set. . A plurality of input terminals and output terminals provided in the optical wavelength cut-through network according to claim 1, to which the plurality of cut-through paths are connected;
Means for connecting the input terminal and the output terminal in a one-to-one relationship;
The optical cross-connect device characterized in that the means for connecting comprises means for periodically changing the output terminal to which the input terminal is connected to different output terminals periodically.

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