JP2003333086A - Photonic node and photonic network - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a photonic network of high flexibility to flexibly deal with addition of a new path, even if the photonic network is constituted, while effectively using network resources by using a few 3R (reshaping, retiming and regenerating) repeaters. <P>SOLUTION: When setting path, the number of non-repeater reachable nodes is calculated, the node being a node positioned at a limit to perform transfer of an optical signal, without requiring the 3R repeater in assuming that the own node is a source node. The calculation result and the number of 3R repeaters own node has are announced to the other nodes. The information. about the number of non-repeater reachable nodes and the 3R repeaters, which are announced from another node, are summed respectively so as to correspond to addresses of the other nodes. The 3R repeater nodes are selected so that the number of 3R repeaters becomes as small as possible to the number of destinations nodes. When there are a plurality of 3R repeater node candidates, a candidate having the largest margin of 3R repeating performance is selected. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a photonic network for switching and connecting optical signals. Especially 3R (R
eshaping, Retiming, Regenerating) A photonic network including photonic nodes for relaying.

[0002]

2. Description of the Related Art In a photonic network, it is necessary to perform 3R processing in the middle of an optical transmission line in consideration of fiber loss, loss, and crosstalk. A conventional photonic network configuration is shown in FIG. To perform the 3R processing, a 3R repeater is inserted in a node in the optical transmission line. 3R
Although it is possible to transmit up to a certain distance without performing processing, a complicated calculation is required to determine the distance. Therefore, as shown in FIG. So that the deterioration of the optical signal can be compensated no matter what route the path is set to.

Alternatively, there is also a usage mode in which a 3R repeater is inserted in a specific route of the photonic network, a path is set by using this as a common route for many paths, and the 3R repeater is shared. However, in this usage mode, the route to be taken in the case of data transfer requiring 3R processing is limited.

[0004]

The 3R repeater is expensive, and if the 3R repeater is not used as much as possible, the photonic network can be realized very economically. However, in the conventional path setting, there is no consideration that the node grasps the usage status of the 3R repeater to perform the path setting, and each node only has to know the predetermined location of the 3R relay. However, if a large number of paths share a small number of 3R repeaters, there is a possibility that a large number of loads will concentrate on some of the 3R repeaters.
If a large number of paths share a small number of 3R repeaters, 3R
The path must always pass through the insertion point of the repeater, which reduces the flexibility of path setting.

For example, even if there is a request for adding a new path to a specific route in which the 3R load is concentrated, there occurs a situation in which the path cannot be set for that route despite the availability of other routes.

The present invention has been made against such a background, and a photonic network having a high flexibility even if a photonic network is configured while effectively utilizing network resources by using a small number of 3R repeaters. An object of the present invention is to provide a photonic node and a photonic network that can realize a network and can flexibly cope with the addition of new paths.

[0007]

According to the present invention, each node advertises information indicating the 3R relay capability of its own node to other nodes,
Each node receives this announcement and
R relay capability is grasped and 3R of each node is set at the time of path setting.
By setting the path considering the relay capacity, 3
It is characterized in that a path can be set for a route with a low R processing load. As a result, it is possible to avoid the situation where the 3R processing load is concentrated on a specific location even when the photonic network is configured while using a small number of 3R relays to effectively use the network resources. Therefore, a highly flexible photonic network can be realized, and an empty route can be effectively used to flexibly cope with the addition of a new path.

That is, the first aspect of the present invention is applied to a photonic network for switching and connecting optical signals,
1R 3R repeater including means for switching and connecting optical signals and means for setting a path between the own node and the destination node when the own node is a source node.
The 3R repeater with or without the above is a photonic node in which either the used state or the unused state is selected, and the feature of the present invention is that the own node or the own node does not have the 3R There is a means for notifying other nodes of the number of 3R repeaters that all nodes that can be connected by relay have.

[0009] The means for making the announcement includes 3 of the own node or all the nodes to which the own node can connect without 3R relay.
It is desirable to periodically announce the number of unused 3R repeaters among the R repeaters.

A second aspect of the present invention is a photonic network including the photonic node of the present invention.

As described above, the source node can grasp all the nodes that perform 3R relay on the show test path up to the destination node and their capabilities by receiving the announcement from the other nodes. On top of that, the number of 3R relays should be reduced to 3
A node that performs R relay can be selected. further,
When there are a plurality of node candidates that perform the same 3R relay with the same number of 3R relays, it is possible to select the node that performs the 3R relay with the largest 3R relay capability.

As a result, even if the photonic network is constructed using a small number of 3R repeaters, a highly flexible photonic network can be realized, and a new path can be flexibly dealt with.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) A photonic node and a photonic network according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing an example of the photonic network of this embodiment. FIG. 2 is a block diagram of the photonic node of this embodiment. FIG. 3 is a diagram showing a notification packet of the first embodiment. FIG. 4 is a diagram showing a 3R relay information list of the first embodiment. FIG. 5 is a flowchart showing the operation of the path setting unit of the first embodiment.

This embodiment is applied to a photonic network for switching and connecting optical signals as shown in FIG. 1, and as shown in FIG. 2, an optical cross-connect 1 for switching and connecting optical signals and its own node When it is a source node, a route calculation unit 2 that calculates a shortest path that minimizes the number of transit nodes between the own node and the destination node, and the own node and the destination node based on the calculation result of this route calculation unit 2. And a path setting unit 3 that sets a path between and, and is a photonic node with or without one or more 3R relays 71 to 7n.

Here, the feature of the first embodiment is that, as shown in FIG. 2, when the own node is assumed to be the source node, it is possible to transfer an optical signal without requiring 3R relay. A 3R relay information calculation unit 5 that calculates a relay-less reachable node that is a located node each time a change occurs in the network topology, a calculation result of the 3R relay information calculation unit 5, and 3R relays 71 to 71 included in the own node.
As shown in FIG. 3, the 3R relay information announcement unit 6 that announces the number of 7n to other nodes by using an OSPF signaling packet
And a 3R relay information collection unit 4 that aggregates information on the number of non-relay reachable nodes and the number of 3R relays announced by other nodes in association with the address of the other node, as shown in FIG. As shown in FIG. 5, when the self-node is the source node, the path setting unit 3 causes the route calculation unit 2 to calculate the show test path to the destination node (step 1), and in the middle of the show test path. It is determined whether or not 3R relay is necessary (step 2), and if necessary, the 3R relay information collection unit 4
On the basis of the totaling result of (3), a node that performs 3R relay is selected so that the number of 3R relays is as small as possible to the destination node (step 3), and when there are a plurality of node candidates that perform this selected 3R relay (step 4). ) Based on the result of counting by the 3R relay information collecting unit 4,
The candidate having the largest margin of 3R relay capability is selected from the node candidates for R relay as an optimum node for 3R relay (step 5), and at this time, based on the result of counting by the 3R relay information collecting unit 4. The number of 3R relays in the recognized node candidates for 3R relay is used as a margin of the 3R relay capability to select a node candidate for 3R relay with the largest number of 3R relays.

(Second Embodiment) A second embodiment will be described with reference to FIGS. 2 and 5 to 7. FIG. 6 is a diagram showing a notification packet of the second embodiment. FIG. 7 shows the 3R of the second embodiment.
It is a figure which shows a relay information list.

The feature of the second embodiment is that, as shown in FIG. 2, a node located at the limit of being able to transfer an optical signal without requiring 3R relay when the own node is assumed to be a source node. 3R relay information calculation unit 5 that calculates a relayless reachable node that is each time the network topology changes, the calculation result of this 3R relay information calculation unit 5 and the number of 3R relays 71 to 7n that the own node has. The 3R relay information notifying unit 6 for notifying the usage status of the 3R relays 71 to 7n to other nodes by the OSPF signaling packet shown in FIG. 6, a non-relay reachable node and the number of 3R relays announced by the other nodes, and As shown in FIG. 7, the information on the usage status of the 3R repeaters is associated with the addresses of the other nodes, and the 3Rs are totaled.
5, the path setting unit 3 causes the route calculation unit 2 to calculate a shortest test path to the destination node when the own node is a source node (step 1). ), It is determined whether or not 3R relay is required in the middle of the show test pass (step 2), and if necessary, the 3R relay information collection unit 4
On the basis of the totaling result of (3), a node that performs 3R relay is selected so that the number of 3R relays is as small as possible to the destination node (step 3), and when there are a plurality of node candidates that perform this selected 3R relay (step 4). ) Based on the result of counting by the 3R relay information collecting unit 4,
The candidate having the largest margin of 3R relay capability is selected from the node candidates for R relay as an optimum node for 3R relay (step 5).

In the second embodiment, as shown in FIG. 7, since the total number of 3R relays and the number of unused 3R relays in other nodes are announced, the path setting unit 3 performs 3R relay. 3R as a margin of 3R relay capability in node candidates
The relevant 3R recognized based on the result of counting by the relay information collecting unit 4.
The number of unused 3R relays in the node candidates for relaying is used as a margin of the 3R relay capability, and a node candidate for 3R relay with the largest number of unused 3R relays is selected.

Alternatively, the path setting unit 3 sets 3R as a margin of 3R relay capability in a node candidate for 3R relay.
The relevant 3R recognized based on the result of counting by the relay information collecting unit 4.
The value obtained by subtracting 1 from the number of unused 3R relays in the node candidate for relaying is divided by the number of all 3R relays in the node candidate for performing 3R relay, and is the most divided result as the margin of the 3R relay capability. Selects a node candidate for 3R relay with a large value.

As described above, it can be expressed whether the margin of the 3R relay capability is high or low depending on whether the usage rate of the 3R relay in the node is high or low. Here, the 3R
The reason why the value obtained by subtracting 1 from the number of unused 3R relays in the node candidate for relay is divided by the number of all 3R relays in the node candidate for 3R relay is as described above. When the number of unused 3R relays is 0, the arithmetic expression is (0-1) / n = -n (n is the number of all 3R relays), and the 3R relay cost has a negative value. However, in such a case, it may be defined as indicating that the 3R relay capability is absent (value “0”).

The 3R relay information announcement unit 6 periodically updates the information on the usage status of the 3R relay, and periodically sends out the announcement including the updated information on the usage status.

(Third Embodiment) A third embodiment will be described with reference to FIGS. 2 and 8 to 11. FIG. 8 is a diagram showing a notification packet of the third embodiment. FIG. 9 shows the third embodiment.
It is a figure which shows a R relay information list. 10 and 11
6 is a flowchart showing the operation of the path setting unit of the third embodiment.

The characteristic feature of the third embodiment is that, as shown in FIG. 2, a node located at the limit where optical signals can be transferred without requiring 3R relay when the own node is assumed to be a source node. 3R relay information calculation unit 5 that calculates a relayless reachable node that is each time a change occurs in the network topology, and 3R relays 71 to 71 included in the own node.
The number of 7n and its use status are announced to other nodes by an OSPF signaling packet as shown in FIG. 8 3
As shown in FIG. 9, the R relay information notifying unit 6 and the information about the number of 3R relays announced by other nodes and the use status thereof are totaled in correspondence with the addresses of the other nodes 3
The R relay information collecting unit 4 is provided, and the path setting unit 3 is configured as shown in FIG.
As shown in (3), when the own node is the source node, the route calculation unit 2 is caused to calculate the show test path to the destination node (step 1), and whether or not 3R relay is required in the middle of the show test path is determined. (Step 2), and if necessary, the 3R relay information collecting unit 4
Based on the aggregated results of 3Rs, there are as few relayless reachable nodes as possible toward the destination node
A node that performs 3R relay is selected so as to have the number of relays (step 3), and when there are a plurality of node candidates that perform the selected 3R relay (step 4), the node is selected based on the aggregation result of the 3R relay information collection unit 4. Of the node candidates for 3R relay, the candidate with the largest margin of 3R relay capability is selected as the node for optimal 3R relay (step 5).
Where it is.

Further, when the own node is a node selected as a node for performing 3R relay from another node,
As shown in FIG. 11, when a 3R relay request is received from an upstream node such as a source node (step 1), a further 3
It is determined whether or not R relay is necessary (step 2), and if necessary, the number of 3R relays is as small as possible until the non-relay reachable node heading toward the destination node based on the counting result of the 3R relay information collection unit 4. A node that performs 3R relay is selected so as to become (step 3), and when there are a plurality of node candidates that perform this selected 3R relay (step 4), the 3R relay is selected based on the aggregation result of the 3R relay information collection unit 4. The candidate having the largest margin of 3R relay capability is selected from among the node candidates to be performed as an optimum node for 3R relay (step 5).

In the third embodiment, as in the second embodiment, as shown in FIG. 9, since the total number of 3R repeaters and the number of unused 3R repeaters in other nodes are announced, the path setting is performed. The unit 3 recognizes the number of unused 3R relays in the node candidate performing the 3R relay, which is recognized based on the aggregation result of the 3R relay information collecting unit 4 as a margin of the 3R relay capability in the node candidate performing the 3R relay. A node candidate for performing 3R relay with the largest number of unused 3R relays is selected as the capacity margin.

Alternatively, the path setting unit 3 sets 3R as the margin of the 3R relay capability in the node candidate for 3R relay.
The relevant 3R recognized based on the result of counting by the relay information collecting unit 4.
The value obtained by subtracting 1 from the number of unused 3R relays in the node candidate for relaying is divided by the number of all 3R relays in the node candidate for performing 3R relay, and is the most divided result as the margin of the 3R relay capability. Selects a node candidate for 3R relay with a large value.

The 3R relay information announcement unit 6 periodically updates the information on the usage status of the 3R relay device, and periodically sends out the announcement including the updated information on the usage status.

(Fourth Embodiment) The function of controlling the photonic node of the present embodiment can be realized by using a computer device which is an information processing device. That is, by being installed in a computer device, it is applied to a photonic network for switching and connecting optical signals to the computer device, and an optical cross connect 1 for switching and connecting optical signals and the own node when the own node is a source node. And a destination node, a route calculation unit 2 that calculates a shortest path that minimizes the number of transit nodes, and a path is set between the own node and the destination node based on the calculation result of this route calculation unit 2. 3R relays 71 to 7n including the path setting unit 3
A program that realizes the function of controlling a photonic node with or without the above, and is located at a limit where optical signals can be transferred without requiring 3R relay when the own node is assumed to be a source node A function corresponding to the 3R relay information calculation unit 5 that calculates a non-relay relay reachable node each time a change occurs in the network topology, the calculation result of the 3R relay information calculation unit 5, and the 3R relays 71 to 71 included in the own node. A function corresponding to the 3R relay information announcement unit 6 that announces the number of 7n to other nodes,
A function corresponding to the 3R relay information collection unit 4 that collects the information of the non-relay reachable node and the number of 3R relays announced from other nodes in association with the address of the other node is realized, and the path setting unit 3 As a function corresponding to the above, when the own node is the source node, the number of 3R relays is reduced to the destination node as much as possible based on the counting result of the 3R relay information collection unit 3.
When there are a plurality of first selection functions that select a node that performs R relay and candidate nodes that perform 3R relay selected by this first selection function, the 3R relay is performed based on the aggregation result of the 3R relay information collection unit 4. Most among the node candidates
A second selection function for selecting a candidate having a large margin of R relay capability is realized, and as the second selection function, the 3R in the node candidate for performing the 3R relay recognized based on the aggregation result of the 3R relay information collection unit 4 is selected. The first embodiment is installed in a computer device by installing a program for realizing a function of selecting a node candidate for performing 3R relay with the largest number of 3R relays, using the number of relays as a margin of the 3R relay capability. The function of controlling the photonic node can be realized.

Alternatively, when the own node is assumed to be the source node, a non-relayable reachable node, which is a node located at the limit of optical signal transfer without requiring 3R relay, is changed every time the network topology changes. The function corresponding to the 3R relay information calculation unit 5 for calculation and this 3R
Calculation result of the relay information calculation unit 5 and 3 of own node
Number of R repeaters 71 to 7n and the 3R repeaters 71 to 7
The function corresponding to the 3R relay information notifying unit 6 for notifying the usage status of n to another node, the non-relay reachable node and the number of 3R relays announced by the other node, and the information on the usage status of the 3R relay are A function corresponding to the 3R relay information collecting unit 4 that collects data corresponding to addresses of other nodes is realized, and as a function corresponding to the path setting unit 3, when the own node is a source node, the 3R relay information collecting unit Based on the aggregation result of 4, reduce the number of 3R relays to the destination node as much as possible 3
When there is a third selection function that selects a node that performs R relay and a plurality of node candidates that perform 3R relay selected by this third selection function, the 3R relay is performed based on the aggregation result of the 3R relay information collection unit 4. Most among the node candidates
By installing a program for realizing a fourth selection function for selecting a candidate having a large margin of R relay capability in a computer device, the computer device is made to realize the function of controlling the photonic node of the second embodiment. You can

Alternatively, when the own node is assumed to be the source node, a non-relayable reachable node, which is a node located at the limit of transferring optical signals without requiring 3R relay, is changed every time the network topology changes. A function corresponding to the 3R relay information calculating unit 5 for calculating, a function corresponding to the 3R relay information notifying unit 6 for notifying other nodes of the number of 3R relays 71 to 7n that the own node has and its usage status, and another node The function corresponding to the 3R relay information collection unit 4 that collects the information of the number of 3R relays and the usage status thereof, which are announced by the device, in association with the address of the other node, and the function corresponding to the path setting unit 3 As
When the own node is the source node, or when the own node is the node selected as the node that performs the 3R relay from other nodes, the node goes as far as possible to the destination node based on the aggregation result of the 3R relay information collection unit 4. A fifth selection function that selects a node that performs 3R relay so that the number of relayless reachable nodes is as small as 3R relay, and if there are multiple node candidates that perform 3R relay selected by the fifth selection function, 3R relay By installing in the computer device a program that realizes a sixth selection function of selecting a candidate with the largest margin of 3R relay capability from among the node candidates that perform the 3R relay based on the aggregation result of the information collection unit 4, The computer device is made to realize the function of controlling the photonic node of the third embodiment. Door can be.

Further, in order for the computer device to realize the function of controlling the photonic nodes of the second and third embodiments, as the fourth or sixth selection function,
The unused 3 in the node candidate performing the 3R relay, which is recognized as the margin of the 3R relay capability in the node candidate performing the 3R relay, based on the aggregation result of the 3R relay information collecting unit 4.
The number of R relays is used as a margin of the 3R relay capability to realize a function of selecting a node candidate for performing 3R relay with the most unused 3R relays, or as the fourth or sixth selection function, The value obtained by subtracting 1 from the number of unused 3R relays in the node candidate performing 3R relay, which is recognized based on the aggregation result of the 3R relay information collection unit 4 as the margin of the 3R relay capability in the node candidate performing 3R relay, is the 3R. A function of selecting a node candidate for performing 3R relay having the largest division result as a margin of the 3R relay capability of a value obtained by dividing the number of all 3R relays in the node candidate for relay is realized.

Further, as a function corresponding to the 3R relay information notification unit 6, a function of periodically updating the information on the usage status of the 3R relay and a notification including the information on the usage status updated by the updating function. And the function of periodically sending

By recording the program of this embodiment on the recording medium of this embodiment, the computer device can install the program of this embodiment using this recording medium. Alternatively, the program of this embodiment can be directly installed in a computer device from a server holding the program of this embodiment via a network.

Thus, using the computer device,
A photonic network with high flexibility can be realized even if a photonic network is configured while making effective use of network resources by using a small number of 3R relays, and a photonic node that can flexibly respond to the addition of new paths And a photonic network can be realized.

[0035]

As described above, according to the present invention,
Even if the photonic network is configured while making effective use of network resources by using a small number of 3R repeaters, it is possible to realize a photonic network with high flexibility and to flexibly cope with the addition of new paths.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a photonic network of this embodiment.

FIG. 2 is a block configuration diagram of a photonic node according to the present embodiment.

FIG. 3 is a diagram showing a notification packet according to the first embodiment.

FIG. 4 is a diagram showing a 3R relay information list of the first embodiment.

FIG. 5 is a flowchart showing the operation of the path setting unit of the first embodiment.

FIG. 6 is a diagram showing a notification packet according to a second embodiment.

FIG. 7 is a diagram showing a 3R relay information list of the second embodiment.

FIG. 8 is a diagram showing a notification packet according to the third embodiment.

FIG. 9 is a diagram showing a 3R relay information list of the third embodiment.

FIG. 10 is a flowchart showing the operation of the path setting unit of the third embodiment.

FIG. 11 is a flowchart showing the operation of the path setting unit of the third embodiment.

FIG. 12 is a diagram showing a conventional photonic network configuration.

[Explanation of symbols]

1 Optical cross connect 2 route calculator 3 pass setting section 4 3R relay information collection unit 5 3R relay information calculation unit 6 3R relay information announcement department 71-7n 3R repeater

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kohei Shiomoto             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation F-term (reference) 5K030 GA08 HA08 HC01 HD02 JA12                       JL03 KA05 KX20 LB05 LD02

Claims (3)

[Claims] 1. A means applied to a photonic network for switching and connecting optical signals, and means for switching and connecting optical signals, and means for setting a path between the own node and a destination node when the own node is a source node. And a photonic node in which one of a 3R (Reshaping, Retiming, Regenerating) repeater is provided or not provided, and the 3R repeater is used or not used. A photonic node comprising means for notifying other nodes of the number of 3R repeaters that all nodes that the node can connect to without relaying 3R. 2. The notification means periodically announces the number of unused 3R relays among the 3R relays of the own node or all the nodes to which the own node can connect without 3R relay. The photonic node according to item 1. 3. A photonic network comprising the photonic node according to claim 1.