Method and system for establishing transmission priority for optical light-trails

• US 20060210268A1
• Filed: 03/15/2005
• Published: 09/21/2006
• Est. Priority Date: 03/15/2005
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Kinoshita, Susumu, Gumaste, Ashwin Anil
• Granted Patent: US 7,466,917 B2
• Time in Patent Office: Days
• US Class Current: 398/31
• CPC Class Codes: H04J 14/0227 Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
• CPC Class Codes: H04J 14/0238 Wavelength allocation for communications one-to-many, e.g. multicasting wavelengths
• CPC Class Codes: H04J 14/0246 using one wavelength per ONU
• CPC Class Codes: H04J 14/0283 WDM ring architectures
• CPC Class Codes: H04J 14/0284 WDM mesh architectures

Abstract

An optical network is operable to carry optical traffic in a plurality of wavelengths between a plurality of nodes. The optical network includes a light-trail, a convener node, one or more intervening nodes, and an end node. The light-trail is established in the optical network between the convener node and the end node and couples the convener node, the intervening nodes, and the end node. Furthermore, the light-trail is associated with one of a plurality of wavelengths. The convener node and the intervening nodes are each operable to determine whether another node having a higher priority is transmitting optical traffic on the light-trail and, in response to determining that no node having a higher priority is transmitting on the light-trail, transmit optical traffic to one of the nodes in the light-trail. The convener node and the intervening nodes are each further operable to indicate to one or more nodes on the light-trail that optical traffic is being transmitted on the light-trail.

Claims

1. An optical network operable to carry optical traffic in a plurality of wavelengths between a plurality of nodes, the optical network comprising:

a light-trail established in the optical network between a convener node and an end node, wherein the light-trail couples the convener node, one or more intervening nodes, and the end node, and wherein the light-trail is associated with one of the plurality of wavelengths;

the convener node and the intervening nodes each operable to;

determine whether another node having a higher priority is transmitting optical traffic on the light-trail;

in response to determining that no node having a higher priority is transmitting optical traffic on the light-trail, transmit optical traffic to one of the nodes in the light-trail; and

indicate to one or more nodes on the light-trail that optical traffic is being transmitted on the light-trail.

2. The optical network of claim 1, wherein the convener node and the intervening nodes are each further operable to indicate to one or more other nodes that optical traffic is being transmitted on the light-trail by transmitting an intimation message to the one or more other nodes in a control channel associated with a different wavelength than the wavelength associated with the light-trail.

3. The optical network of claim 2, the intimation message is transmitted to all nodes in the light-trail.

4. The optical network of claim 2, wherein the intimation message is transmitted to nodes in the light-trail that have a lower priority than the node transmitting the intimation message.

5. The optical network of claim 1, wherein each of the convener node and the one or more intervening nodes is operable to determine whether another node having a higher priority is transmitting based on a previously-received intimation message from the node having the higher priority.

6. The optical network of claim 1, wherein the convener node is further operable to establish the optical light-trail by transmitting, in a control channel associated with a different wavelength than the wavelength associated with the light-trail, a setup message to the intervening nodes and the end node.

7. The optical network of claim 6, wherein each of the one or more intervening nodes is further operable to configure a wavelength-blocking unit of that intervening node, in response to receiving the setup message, to allow optical traffic propagating at the wavelength associated with the light-trail to pass through that intervening node.

8. The optical network of claim 7, wherein the convener node is further operable to configure a wavelength-blocking unit of the convener node to prevent optical traffic propagating at the wavelength associated with the light-trail from passing through the convener node;

and wherein the end node is further operable to configure a wavelength-blocking unit of the end node, in response to receiving the setup message, to prevent optical traffic propagating at the wavelength associated with the light-trail from passing through the end node.

9. The optical network of claim 1, wherein each of the convener node and the intervening nodes is operable to store a light-trail table that, when a node is transmitting on the light-trail, identifies a priority associated with the node transmitting on the light-trail, and wherein the convener node and each of the intervening nodes are operable to determine whether a node associated with a higher priority is transmitting based on the light-trail table.

10. The optical network of claim 1, wherein each of the convener node and the one or more intervening nodes is operable to transmit optical traffic by:

determining whether any node associated with a lower priority is transmitting on the light-trail;

in response to determining a node having with a lower priority is transmitting on the light-trail, transmit an intimation message to the node associated with the lower priority; and

transmitting optical traffic on the light-trail.

11. The optical network of claim 10, wherein the node having the lower priority is operable to terminate a transmission of optical traffic on the light-trail in response to receiving the intimation message.

12. A method for providing optical communication, comprising:

determining whether any node having a higher priority than a first node is transmitting on a light-trail, the light-trail established between a convener node and an end node in an optical network and coupling the convener node, one or more intervening nodes, and the end node, wherein the light-trail is associated with one of a plurality of wavelengths on which an optical network carries optical traffic;

in response to determining that no other node having a higher priority than the first node is transmitting optical traffic on the light-trail, transmitting optical traffic from the first node to a second node that is located in the light-trail; and

indicating to one or more nodes in the light-trail that optical traffic is being transmitted on the light-trail.

13. The method of claim 12, wherein indicating to one or more other nodes comprises transmitting, in a control channel associated with a different wavelength than the wavelength associated with the light-trail, an intimation message from the first node to one or more other nodes.

14. The method of claim 13, wherein indicating to one or more other nodes comprises transmitting an intimation message to all nodes on the light-trail.

15. The method of claim 13, wherein indicating to one or more other nodes comprises transmitting an intimation message to nodes on the light-trail that have a lower priority than the first node.

16. The method of claim 12, wherein determining whether a node having a higher priority is transmitting comprises determining, based on an intimation message previously received by the first node from a node having a higher priority, that the node having a higher priority is transmitting.

17. The method of claim 12, further comprising establishing the optical light-trail by transmitting, in a control channel associated with a different wavelength than the wavelength associated with the light-trail, a setup message from the convener node to the intervening nodes and the end node.

18. The method of claim 17, further comprising configuring a wavelength-blocking unit of each intervening node, in response to receiving the setup message at that intervening node, to allow optical traffic propagating at the wavelength associated with the optical light-trail to pass through that intervening node.

19. The method of claim 18, further comprising:

configuring a wavelength-blocking unit of the convener node to prevent optical traffic propagating at the wavelength associated with the light-trail from passing through the convener node; and

configuring a wavelength-blocking unit of the end node, in response to receiving the setup message, to prevent optical traffic propagating at the wavelength associated with the light-trail from passing through the end node.

20. The method of claim 12, wherein determining whether a node associated with a higher priority is transmitting comprises determining whether a node associated with a higher priority is transmitting on the light-trail based on a light-trail table that identifies a priority associated with any node currently transmitting on the light-trail.

21. The method of claim 12, further comprising:

determining whether any node associated with a lower priority than the first node is transmitting on the light-trail;

in response to determining that a node associated with a lower priority than the first node is transmitting on the light-trail, transmit an intimation message to the node associated with the lower priority; and

transmitting optical traffic from the first node to a second node on the light-trail.

22. The method of claim 21, further comprising terminating a transmission of optical traffic on the light-trail by the node having the lower priority in response to the node having the lower priority receiving the intimation message.