Method for protecting and restoring link using optical label merging and dynamic resource sharing with network load
View Patent ↗Disclosed herein is a method for protecting and restoring a link in an OBS network. The method includes a step of transmitting/receiving a liveness-confirming message for confirming liveness of the link between an up-node and a down-node respectively connected to both ends of the link at a predetermined message transmission period, to judge whether a fault is generated on the link, a step in which the up-node and down-node respectively update link information when it is judged that the link fault is not generated, and a step of restoring the link having the fault using predetermined restoration channel information based on an offered load measured when the link is in a normal state when it is judged that the link fault is generated. Accordingly, a link having a problem can be effectively protected and restored in the OBS network.
1. A method for protecting and restoring a link, comprising:
transmitting/receiving a liveness-confirming message for confirming the liveness of the link between an up-node and a down-node respectively connected to both ends of the link at a predetermined message transmission period, to judge whether a fault is generated on the link;
allowing the up-node and down-node to update link information, respectively when it is judged that the link fault is not generated; and
restoring the link having the fault using predetermined restoration channel information based on an offered load measured when the link is in a normal state when it is judged that the link fault is generated;
the up-node merging a large number of data bursts in a transmission wavelength into a small number of protection wavelengths using the restoration channel information and transmitting the protection wavelengths; and
the down-node restoring the merged wavelengths to the transmission wavelength through wavelength conversion using the restoration channel information.
2. The method as claimed in claim 1 , wherein it is judged that the link fault is generated when the liveness-confirming message is not received during the message transmission period.
3. The method as claimed in claim 2 , wherein it is judged that the link fault is generated when the liveness-confirming message is not received while the message transmission period is repeated more than once.
4. The method as claimed in claim 2 , wherein it is judged that the link fault is generated when the liveness-confirming message is not received while the message transmission period is repeated more than twice.
5. The method as claimed in claim 1 , wherein restoring the link comprises:
allowing the up-node to transmit a restoration-requesting message (request message) including the restoration channel information to the down-node;
allowing the down-node to transmit a response message to the up-node; and
allowing the down-node to update wavelength routing information using the restoration channel information.
6. The method as claimed in claim 5 , wherein the request message includes a destination node identification field, a source node identification field, a type of field for deciding the type of message, a time field for storing information on the time during which the message lives, and a control information field for storing previously appointed restoration channel information.
7. The method as claimed in claim 5 , wherein the response message includes a destination node identification field, a source node identification field, a type field for deciding the type of message, a time field for storing information on the time during which the message lives, and a control information field for storing ACK/NAK to response request message of the restoration channel information included in the request message.
8. The method as claimed in claim 5 , wherein restoring the link further includes the down-node requesting the up-node to transmit the restoration-requesting message when the request message is not transmitted during a predetermined restoration waiting time.
9. The method as claimed in claim 8 , wherein requesting the transmission of the request message comprises transmitting a message including a destination node identification field, a source node identification field, a type field for deciding the type of message, a time field for storing information on the time during which the message lives, and a control information field for storing information that requests the up-node to urgently transmit the request message.
10. The method as claimed in claim 5 , wherein restoring the link further includes the up-node requesting the down-node to transmit the response message when the response message from the down-node is not received during a predetermined response waiting time.
11. The method as claimed in claim 10 , wherein requesting the transmission of the response message comprises transmitting a message including a destination node identification field, a source node identification field, a type field for deciding the type of message, a time field for storing information on the time during which the message lives, and a control information field for storing information that requests the down-node to urgently transmit the response message.
12. The method as claimed in claim 1 , wherein the liveness-confirming message includes a destination node identification field, a source node identification field, a type field for deciding the type of message, a time field for storing information on the time during which the message lives, and a control information field for storing message transmission time at each node.