Relay node in optical networks

Abstract

A relay node used in a WDM optical network is disclosed. The relay node includes: a high-speed side port configured to send and receive a high-speed signal; a low-speed side port configured to send and receive a low-speed signal; a unit configured to generates a checking message for requesting another node to report constraint information of a low-speed side port of the another node, wherein the constraint information relates to adding an optical signal from the low-speed side port to a high-speed side port of the another node or dropping an optical signal from the high-speed side port to the low-speed side port of the another node; a unit configured to generate a response message including the constraint information of the own node in response to receiving the checking message sent from the another node; and a storing unit configured to store at least the constraint information of the another node.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings, in which:

FIG. 1 shows a relay node having no constraint of wavelengths and ports;

FIG. 2 shows a relay node having constraints of wavelengths and ports;

FIG. 3 shows a WDM optical network in an embodiment of the present invention;

FIG. 4 shows a method for establishing a connection according to the embodiment of the present invention;

FIG. 5 is a partial functional block diagram of a relay node;

FIG. 6A shows an example of the constraint information stored in the database;

FIG. 6B shows an example of the constraint information stored in the database;

FIG. 6C shows an example of the constraint information stored in the database;

FIG. 7A shows a transmission scheme for a checking/response message;

FIG. 7B shows a transmission scheme for a checking/response message;

FIG. 8A shows a transmission scheme for a checking/response message;

FIG. 8B shows a transmission scheme for a checking/response message;

FIG. 9 shows a situation (1) in which the checking/response message is transmitted;

FIG. 10 shows a situation (1-2) in which the checking/response message is transmitted;

FIG. 11A shows a situation (2) in which the checking/response message is transmitted in a bus type network;

FIG. 11B shows a situation (2) in which the checking/response message is transmitted in a ring type network;

FIG. 12 shows a situation (2-2) in which the checking/response message is transmitted in a bus type network;

FIG. 13A shows a situation (2-3) in which the checking/response message is transmitted in a ring type network;

FIG. 13B shows a situation (2-3) in which the checking/response message is transmitted in a ring type network;

FIG. 14A shows a situation (2-4) in which the checking/response message is transmitted in a ring type network;

FIG. 14B shows a situation (2-4) in which the checking/response message is transmitted in a ring type network;

FIG. 15A shows a situation (3) in which the checking/response message is transmitted in a bus type network;

FIG. 15B shows a situation (3) in which the checking/response message is transmitted in a ring type network;

FIG. 16 shows a situation (3-2) in which the checking/response message is transmitted in a bus type network;

FIG. 17A shows a situation (4) in which the checking/response message is transmitted in a bus type network;

FIG. 17B shows a situation (4) in which the checking/response message is transmitted in a ring type network;

FIG. 18 shows a situation (4-2) in which the checking/response message is transmitted in a bus type network.

Claims

1. A relay node used in a WDM optical network, comprising: a high-speed side port configured to send and receive a high-speed signal;a low-speed side port configured to send and receive a low-speed signal;a unit configured to generate a checking message for requesting another node to report constraint information of a low-speed side port of the another node, wherein the constraint information relates to adding an optical signal from the low-speed side port to a high-speed side port of the another node or dropping an optical signal from the high-speed side port to the low-speed side port of the another node;a unit configured to generate a response message including the constraint information of the own node in response to receiving the checking message sent from another node; anda storing unit configured to store at least the constraint information of the another node.

2. The relay node as claimed in claim 1, wherein the checking message is sent when the relay node starts up.

3. The relay node as claimed in claim 1, wherein the checking message is sent periodically.

4. The relay node as claimed in claim 1, wherein the checking message is sent when usage of both or one of the high-speed side port and the low-speed-side port is changed.

5. The relay node as claimed in claim 1, wherein both or one of the checking message and the response message is transmitted via the high-speed side port.

6. The relay node as claimed in claim 1, both or one of the checking message and the response message is transmitted over a line that is prepared separately from an optical fiber for the WDM optical network.

7. The relay node as claimed in claim 1, both or one of the checking message and the response message includes identification information of a destination node, a source node, a checking source node and the low-speed side port.

8. The relay node as claimed in claim 1, wherein the constraint information includes information indicating a use status of the low-speed side port.

9. The relay node as claimed in claim 1, wherein the constraint information includes information indicating a high-speed side port to which an optical signal can be added or from which an optical signal can be dropped.

10. The relay node as claimed in claim 1, wherein the checking message sent from the own node includes constraint information of the own node.

11. The relay node as claimed in claim 1, wherein the checking message is generated and sent individually for each of other nodes.

12. The relay node as claimed in claim 1, wherein the checking message is sent only to an adjacent other node.

13. The relay node as claimed in claim 12, wherein when a checking source of a checking message received from another node is the own node, transfer of the checking message to the adjacent other node is prohibited.

14. The relay node as claimed in claim 1, wherein the checking message sent from a checking source is transmitted to a plurality of adjacent nodes.

15. The relay node as claimed in claim 1, wherein the checking message includes checking identification information that is assigned to each checking activity.

16. The relay node as claimed in claim 15, wherein when the relay node receives the checking message including checking identification information the same as checking identification information of another checking message for which a response is already sent, generation of a response message is prohibited.

17. The relay node as claimed in claim 1, wherein when a generated new response message is the same as a response message that is already sent, transmission of the new response message is prohibited

18. The relay node as claimed in claim 1, wherein when the relay node is an end node of a bus type WDM optical network, the relay node sends a response message, and the checking message sent from the own node includes constraint information of the own node.

19. The relay node as claimed in claim 1, wherein constraint information of the own node is added to the checking message received from an adjacent node, and the checking message to which the constraint information is added is sent to another adjacent node or to a checking source.

20. The relay node as claimed in claim 19, wherein a response message is sent to the adjacent node.