JP2003333082A - Photonic node - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To flexibly cope with addition of a new path by realizing a highly flexible photonic network, even when configuring a photonic network, while effectively utilizing a network resource by using a small number of 3R repeaters. <P>SOLUTION: To set a path with a smallest possible number of 3R repeaters, when setting a path, a non-relay reachable node as a node, positioned at a limit of being capable of transferring an optical signal without requiring 3R relay, when assuming that the own node is a source node is calculated, the calculation result is announced to other nodes, information of the non-relay reachable node announced by other nodes is made to correspond to addresses of the other nodes and respectively added, and a node for performing 3R relay so that the number of the 3R relay to the destination becomes as small as possible is selected, based on the tabulated result when setting a path. <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. It is possible to transmit up to a certain distance without performing 3R processing, but since complicated calculation is required to determine the distance, as shown in FIG. A device is inserted so that deterioration of an optical signal can be compensated for whatever route is set to a route.

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 of setting the path without using the 3R repeater as much as possible, and each node only knows a predetermined location of the 3R repeater. There are many cases in which 3R relay is redundantly performed even on a route that does not require 3R relay.

Such a redundant 3R relay is used for a small number of 3Rs.
If a photonic network including repeaters is used, a large number of paths share a small number of 3R repeaters, which may cause a problem that a large number of loads are concentrated on some of the 3R repeaters. . Also, if a large number of paths share a small number of 3R repeaters, it is necessary for the paths to pass through the insertion points of the 3R repeaters without fail, and the flexibility of path setting deteriorates.

For example, even if there is a request for adding a new path to a specific route in which the 3R load is concentrated, a situation occurs 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 using network resources by using a small number of 3R repeaters. It is an object of the present invention to provide a photonic node that can realize a nick network and can flexibly cope with the addition of new paths.

[0008]

According to the present invention, each node grasps information of a node (called a non-relayable reachable node) which can be reached from the own node without 3R relay, and when the path is set, the information is not provided from the own node. 3 to relay reachable node
It is characterized in that the path setting without the R relay is preferentially performed, and the path setting is performed with the smallest possible number of 3R relays. 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 present invention is applied to a photonic network for switching and connecting optical signals, and a path is provided between a means for switching and connecting optical signals and the own node and the destination node when the own node is a source node. And a means for setting one or more 3R repeaters, or not, wherein the 3R repeater is a photonic node selecting either a used state or an unused state.

Here, a feature of the present invention is that a non-relayable reachable node, which is a node that can transfer an optical signal without requiring 3R relay when it is assumed that the own node is a source node, has a network topology. And a recording means for recording the IP address of the non-repeater reachable node measured by the measuring means.

As described above, each node records the information of the non-relay reachable node so that when the self node becomes the source node, the path setting from the self node to the non-relay reachable node is given priority. By doing so, the route with the smallest number of 3R relays can be selected as the route to the destination node. As a result, it is possible to realize a photonic network with high flexibility even when the photonic network is configured by using a small number of 3R relays while effectively using network resources, and it is possible to flexibly deal with the addition of new paths. it can.

[0012] It is preferable that the apparatus further comprises means for publishing the IP address of the non-relay reachable node measured by the measuring means to another node.

It is desirable that the apparatus further comprises means for notifying other nodes of the connection information of the path to the non-relay reachable node measured by the measuring means. This allows
Each node, when its own node becomes the source node,
When selecting the route to the destination node, the connection information of the node can be easily recognized and the route can be easily selected.

It is desirable to have a trunk device for testing whether or not a signal can be normally received, and to provide an inserting means for inserting the trunk device or the 3R repeater into a path passing through the own node. Thereby, each node can accurately grasp the non-relay reachable node from the own node.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) A photonic node according to a first embodiment will be described with reference to FIGS.
FIG. 1 is a diagram showing a node configuration of the first embodiment. FIG. 2 is a diagram showing an example of the advertisement packet of this embodiment. FIG. 3 is a diagram showing the non-relayable reachable node information of this embodiment. FIG. 4 is a diagram showing an example of the advertisement packet of this embodiment. FIG. 5 is a diagram showing non-relayable reachable node information of the present embodiment. FIG. 6 is a diagram for explaining a method of determining a reachable range without relay according to the present embodiment.

The first embodiment is applied to a photonic network for switching and connecting optical signals, and as shown in FIG.
An optical cross connect 1 for switching and connecting optical signals, a route calculation unit 2 for calculating a shortest path that minimizes the number of transit nodes between the own node and the destination node when the own node is a source node, and A photonic node that includes a path setting unit 3 that sets a path between its own node and a destination node based on the calculation result of the route calculation unit 2 and includes one or more 3R relays 71 to 7m. .

Here, the feature of the first embodiment is that when the own node is assumed to be the source node,
An unrepeatered reachable node calculation unit 5 that measures an unrepeatered reachable node, which is a node located at the limit where optical signals can be transferred without requiring R relay, every time a change occurs in the network topology, and the unrepeatered reachable node. As shown in FIG. 2, the measurement result of the node calculation unit 5 announces the non-relayable reachable node information announcement unit 6 that announces to other nodes using the OSPF signaling packet, and the non-relayable reachable that is announced by the other nodes Figure 3 shows the node information.
As shown in FIG. 4, the non-relayable reachable node information collection unit 4 records the addresses corresponding to the addresses of the other nodes.
And the path setting unit 3 includes a relayless reachable node information collecting unit 4 when the own node is a source node.
Based on the recording result of (3), the node that performs 3R relay is selected so that the number of 3R relays is as small as possible to the destination node.

Further, as shown in FIG. 4, the relayless reachable node information announcement unit 6 can also advertise connection information from the own node to the relayless reachable node. According to this, the relayless reachable node information collection unit 4 can grasp the connection relationship from the own node to the relayless reachable node as the network topology information as shown in FIG.

Further, as shown in FIG. 1, a signal reception test trunk 8 for receiving an optical signal coming from another node and determining whether or not the optical signal requires 3R relay is provided. The test trunk 8 notifies the other node of the test result.

The first embodiment will be described in more detail below.

It is possible to adaptively insert the 3R repeaters 71 to 7m in the interface units 91 to 9m. FIG. 6 shows a method of determining a 3R non-relay section using this node. Signals are sequentially transmitted from the source node, and the signal reception test by the signal reception test trunk 8 is carried out at each node. As a result, the K-th node could receive the signal without relaying. The reception level is insufficient at the (K + 1) th stage, that is, up to the Kth stage is a reachable range without 3R.

In the example of FIG. 6, the 3R repeater is inserted in the Kth stage, but the 3R repeater may be inserted in the node before the Kth stage. That is, the node can adaptively insert the 3R relay as shown in FIG. 1, and for example, the K-stage node mostly uses the 3R relay, and the number of newly available 3R relays decreases. In the case where it has been removed, it is sufficient to insert it in the K-1th stage.

FIG. 5 is a network diagram showing the reachable range without relay when node A is the source node. From node A, nodes # 1, # 3, # 5, #
It can be seen that the nodes within the range of 8 and # 10 are reachable without the 3R relay.

As shown in FIG. 2, each node voluntarily announces the information of the reachable node without relay to the neighboring nodes. OS is an example of a packet to be announced
For example, the IP address of each reachable node is accommodated in the PF packet and is announced. Alternatively, as shown in FIG. 5, it is possible to publicize by showing a non-relaying route. According to this, it is understood that it is possible to transfer a non-relay path through, for example, the route # 2 → # 1.

(Second Embodiment) The configuration of the node of the second embodiment will be described with reference to FIG. In the node of the second embodiment, stationary 3R repeaters 71 to 7n are mounted, and the input line m
For a book, it is possible to economically realize a node by providing n 3n repeaters 71 to 7n (n << m).

[0026]

As described above, according to the present invention,
By using a small number of 3R repeaters, a photonic network with high flexibility can be realized even if a photonic network is configured while making effective use of network resources, and a new path can be flexibly dealt with.

[Brief description of drawings]

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

FIG. 2 is a diagram showing an example of a notification packet of this embodiment.

FIG. 3 is a diagram showing relayless reachable node information according to the present embodiment.

FIG. 4 is a diagram showing an example of a notification packet of this embodiment.

FIG. 5 is a diagram showing relayless reachable node information according to the present embodiment.

FIG. 6 is a diagram for explaining a method for determining a reachable range without relay according to the present embodiment.

FIG. 7 is a diagram showing a node configuration of a second embodiment.

FIG. 8 is a configuration diagram of a conventional photonic network.

[Explanation of symbols]

1 Optical cross connect 2 route calculator 3 pass setting section 4 Relayless reachable node information collection unit 5 Repeaterless reachable node calculator 6 Non-relayable reachable node information public notice department 71-7n, 7m 3R repeater 8 signal reception test trunk 91-9m interface section

   ─────────────────────────────────────────────────── ─── 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                       MA01 MA04 MB04 MC03 MD07

Claims (4)

[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. In the photonic node that includes one or more 3R (Reshaping, Retiming, Regenerating) repeaters or does not include, and the 3R repeater selects either a used state or an unused state, Measuring means for measuring a repeaterless reachable node, which is a node capable of transferring an optical signal without requiring 3R relay when it is assumed to be a source node, each time a change occurs in the network topology; And a recording means for recording the IP address of the repeaterless reachable node. Kunodo. 2. The photonic node according to claim 1, further comprising means for notifying an IP address of the repeaterless reachable node measured by the measuring means to another node. 3. The photonic node according to claim 1, further comprising means for publicizing to another node the connection information of the path to the non-relay reachable node measured by the measuring means. 4. A trunk device for testing whether or not a signal can be normally received, and an inserting means for inserting the trunk device or the 3R repeater into a path passing through the own node. Photonic node described in Crab.