SEGMENT ROUTING FOR OPTICAL NETWORKS

• US 20170311056A1
• Filed: 04/22/2016
• Published: 10/26/2017
• Est. Priority Date: 04/22/2016
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: MEHRVAR, HAMID
• Granted Patent: US 10,750,255 B2
• Time in Patent Office: Days
• CPC Class Codes: H04J 14/0267 Optical signaling or routing
• CPC Class Codes: H04J 2203/0023 Routing/path finding
• CPC Class Codes: H04J 2203/0053 Routing
• CPC Class Codes: H04L 45/62 Wavelength based optical switching H04Q11/0062
• CPC Class Codes: H04L 49/25 Routing or path finding in a switch fabric
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 11/0066 Provisions for optical burst or packet networks
• CPC Class Codes: H04Q 2011/0009 using wavelength filters
• CPC Class Codes: H04Q 2011/0015 using splitting combining
• CPC Class Codes: H04Q 2011/002 using optical delay lines or optical buffers or optical recirculation
• CPC Class Codes: H04Q 2011/0039 Electrical control
• CPC Class Codes: H04Q 2011/0041 Optical control
• CPC Class Codes: H04Q 2011/0069 using dedicated optical channels
• CPC Class Codes: H04Q 2011/0073 Provisions for forwarding or routing, e.g. lookup tables
• CPC Class Codes: H04Q 2011/0088 Signalling aspects

Abstract

Aspects of the disclosure involve a source node, having some predetermined knowledge of the optical network generating a list of nodes and/or optical links between nodes that form a route in the optical network from the source node to the destination node. The nodes in the optical network do not necessarily need to know the entire route from source node to destination node. Each node simply decodes the control information identifying the next hop in the route towards the destination node. By utilizing the decoded control information identifying the next hop, a switch in the node can be controlled to route the optical signal including the payload and some or all of the control information onto the next optical link toward the destination node.

Claims

1. A method for operating an optical switch node in a segment routed optical network, the method comprising:

receiving from a first prior node, over a first optical link in the optical network, a first optical signal carrying a payload and control information associated with the optical switch node and with subsequent optical switch nodes in a segment routed path;

controlling a switching fabric in accordance with the control information associated with the optical switch node read from the received first optical signal in a manner non-destructive to the control information associated with the subsequent optical switch nodes in the segment routed path;

forwarding to a subsequent node in the optical network, through the switching fabric, in a manner determined in accordance with the read control information, an optical signal carrying the received payload and the control information associated with the subsequent optical switch nodes in the segment routed path.

2. The method of claim 1 further comprising:

filtering the received first optical signal to extract a wavelength channel associated with the optical switch node; and

reading the control information from the extracted wavelength channel.

3. The method of claim 1 further comprising:

tapping the received first optical signal; and

reading the control information from the tapped optical signal.

4. The method of claim 2 wherein filtering the received first optical signal to extract the wavelength channel associated with the optical switch node comprises:

extracting all wavelength channels carrying control information; and

reading the control information comprises reading the control information from an extracted wavelength channel associated with the optical switch node.

5. The method of claim 4 further comprising:

combining wavelength channels carrying control information not associated with the optical switch node with the payload prior to forwarding to the subsequent optical switch nodes the optical signal carrying the received payload and the control information associated with the subsequent optical switch nodes in the segment routed path.

6. The method of claim 1 further comprising delaying the received first optical signal prior to forwarding while the control information associated with the optical switch node is read.

7. The method of claim 1, wherein receiving the first optical signal comprises:

receiving the payload and control information in a same waveband comprising a plurality of wavelength channels;

or

receiving the control information and the payload in separate respective wavebands, each comprising a plurality of wavelength channels.

8. The method of claim 7, wherein receiving the payload and control information in separate respective wavebands comprises receiving the control information in one of a 1310 nm waveband or a 1550 nm waveband and receiving the payload in the other of the 1310 nm waveband or the 1550 nm waveband.

9. The method of claim 1, wherein the control information comprises at least one of:

routing information including a list of optical links or optical switch nodes in the segment routed path, the list defining at least a route from the optical switch node to a destination optical switch node;

burst mode reset information; and

update and/or management information.

10. The method of claim 2, wherein:

filtering the optical signal to extract the wavelength associated with the optical switch node comprises dropping at least one wavelength channel including control information associated with the optical switch node; and

reading the control information from the extracted wavelength channel comprises converting the dropped at least one wavelength channel comprising control information associated with the optical switch node into an electrical signal for controlling an optical switch fabric in the optical switch node.

11. The method of claim 10 further comprising:

converting at least a portion of the electrical signal including control information not associated with the optical switch node back into an optical signal on a wavelength channel dedicated for control information for all optical switch nodes in the segment routed optical network; and

before switching occurs, recombining the optical signal on the dedicated wavelength channel for all optical switch nodes with a through signal remaining from the received optical signal after dropping the at least one wavelength channel associated with the optical switch node.

12. The method of claim 1 further comprising receiving from a second prior node over a second optical link in the optical network, a second optical signal carrying a second payload and second control information for all subsequent nodes in a segment routed path, wherein the second control information is on a same first wavelength channel as the channel information received from the first prior node over the first optical link, the method further comprising:

controlling the switching fabric in accordance with the second control information in the received second optical signal associated with the optical switch node read from the received second optical signal in a manner non-destructive to the control information associated with other optical switch nodes in the segment routed path;

forwarding to a subsequent node in the optical network, through the switching fabric, in a manner determined in accordance with the read second control information, the second optical signal carrying the received payload and the control information associated with subsequent nodes in the optical network.

13. The method of claim 1 further comprising receiving from a second prior node over a second optical link in the optical network, a second optical signal carrying second payload and second control information, wherein the second control information is on a different wavelength channel than the channel information received from the first prior node over the first optical link, the method further comprising;

controlling the switching fabric in accordance with the second control information in the received second optical signal associated with the optical switch node read from the received second optical signal in a manner non-destructive to the control information associated with other optical switch nodes in the segment routed path;

forwarding to a subsequent node in the optical network, through the switching fabric, in a manner determined in accordance with the read second control information, the second optical signal carrying the received payload and the control information associated with subsequent nodes in the optical network.

14. The method of claim 2, wherein filtering the received first optical signal to extract the wavelength channel associated with the optical switch node comprises:

dropping the wavelength channel comprising control information associated with the optical switch node; and

passing one or more other wavelength channels comprising control information not associated with the optical switch node, wherein the control information that is passed by the filtering traverses the optical switching node together with the payload.

15. The method of claim 2 wherein filtering the received first optical signal to extract the wavelength channel associated with the optical switch node comprises:

filtering the received first optical signal to drop a waveband including a plurality of wavelength channels comprising at least one wavelength channel carrying control information associated with the optical switch node and at least one wavelength channel carrying control information not associated with the optical switch node; and

filtering the dropped waveband in order to drop the at least one wavelength channel carrying control information associated with the optical switch node and passing the at least one wavelength channel carrying control information not associated with the optical switch node.

16. The method of claim 1 further comprising:

extracting routing information relevant to the optical switch node from the control information in the received optical signal; and

forwarding an optical signal carrying the received payload and the control information associated with subsequent nodes in the segment routed path without modifying the payload or the control information not relevant to the optical switch node.

17. A method for operating a source node in a segment routed optical network, the method comprising:

generating a segment routed path comprising an ordered list of optical switch nodes;

generating control information for each of the optical switch nodes in the ordered list;

encoding the generated control information into at least one control wavelength channel; and

transmitting a payload along with the encoded control information to a first optical switch node in the ordered list.

18. The method of claim 17 wherein the ordered list comprises an identification of a destination node, and the generated control information comprises control information other than routing information for the destination node.

19. The method of claim 17 wherein encoding the generated control information into at least one control wavelength channel comprises:

encoding the generated control information into a single wavelength channel;

or

encoding the generated control information into a plurality of wavelength channels, wherein each wavelength channel is encoded with the generated control information for a particular optical link or optical switch node in the segment routed optical network.

20. The method of claim 17 wherein generating control information for each of the optical switch nodes in the ordered list further comprises appending a burst mode reset for a destination node to the control information.

21. The method of claim 17 wherein generating control information for each of the optical switch nodes in the ordered list further comprises appending at least one of update and management information to the control information.

22. An optical switch node for use in a segment routed optical network comprising:

an input port configured to receive from a prior node in the optical network, over an optical link, an optical signal carrying a payload and control information for the optical switch node and for subsequent optical switch nodes in a segment routed path;

a wavelength diverter configured to optically divert a portion of the received optical signal;

an optical switch fabric optically coupled to the at least one input port configured to route an optical signal carrying the received payload and the control information associated with at least subsequent nodes in a segment routed path to a subsequent node in the optical network; and

a controller, optically coupled to the wavelength diverter and the optical switch fabric, the controller configured to control the optical switch fabric to direct, to an output port selected in accordance with information carried in the diverted portion of the received optical signal.

23. The optical switch node of claim 22 wherein the controller s configured to:

read control information associated with the optical switch node in the diverted portion of the received optical signal in a manner non-destructive to the control information associated with other nodes in the segment routed path;

control the optical switch fabric to route the optical signal in accordance with the read control information associated with the optical switch node.

24. The optical switch node of claim 22 wherein the wavelength diverter comprises:

at least one optical filter, each optical filter optically coupled to one or more of the at least one input port and the controller, the at least one optical filter configured to filter the received optical signal to extract a wavelength channel associated with the optical switch node; and

wherein the controller reads the control information associated with the optical switch node from the extracted wavelength channel.

25. The optical switch node of claim 22 wherein the wavelength diverter comprises:

an optical splitter, the optical splitter optically coupled to one or more of the at least one input port and the controller, the optical splitter configured to tap the received optical signal; and

wherein the controller reads the control information associated with the optical switch node from the tapped optical signal.

26. The optical switch node of claim 24, wherein:

the at least one optical filter is configured to filter the received optical signal to extract a plurality of wavelength channels, the plurality of wavelength channels carrying control information associated with the optical switch node and carrying control information not associated with the optical switch node; and

wherein the controller is configured to read the control information from a wavelength channel associated with the optical switch node.

27. The optical switch node of claim 22 further comprising a delay element configured to delay the received optical signal prior to routing while the control information associated with the optical switch node is read.

28. The optical switch node of claim 22, wherein the control information comprises at least one of:

routing information including a list of optical links or optical switch nodes in the segment routed path, the list defining at least a route from a current optical switch node to a destination optical switch node;

burst mode reset information; and

update and/or management information.

29. The optical switch node of claim 24, wherein:

the at least one optical filter comprises a respective optical filter optically coupled to each of the at least one input ports, wherein each optical filter is configured to filter a single wavelength channel;

or

the at least one optical filter comprises a respective optical filter optically coupled to each input port, wherein the optical filters are configured to each filter a different wavelength channel.

30. The optical switch node of claim 27, wherein the at least one optical filter is configured to:

drop a wavelength channel comprising control information associated with the optical switch node; and

pass one or more wavelength channel comprising control information not associated with the optical switch node, wherein the control information that is passed by the at least one optical filter traverses the optical switch node together with the payload.

31. The optical switch node of claim 22, wherein the at least one optical filter comprises:

a first optical filter configured to filter the received optical signal to drop a waveband including a plurality of wavelength channels comprising at least one wavelength channel carrying control information associated with the optical switch node and at least one wavelength channel carrying control information not associated with the optical switch node; and

at least one second optical filter configured to filter an optical signal including the dropped waveband in order to drop the at least one wavelength channel carrying control information associated with the optical switch node and pass the at least one wavelength channel carrying control information not associated with the optical switch node.

32. The optical switch node of claim 31, further comprising a combiner configured to combine at least one wavelength channel carrying control information not associated with the optical switch node with a through signal carrying the payload before switching occurs.

33. The optical switch node of claim 30, wherein the controller is further configured to, based on the at least a portion of the control information, perform at least one of triggering a burst mode reset or updating/managing the optical switch node.

34. An optical switch node for use in a segment routed optical network comprising:

a controller configured to;

generate a segment routed path through the optical network comprising an ordered list of optical switch nodes;

generate control information for each of the optical switch nodes in the ordered list;

encode the generated control information into at least one control wavelength channel; and

transmit a payload along with the encoded control information to a first optical switch node in the ordered list.

35. The optical switch node of claim 34, wherein the controller is configured to:

encode the generated control information on a plurality of control wavelength channels, wherein each control wavelength channel is encoded with the generated control information for a particular optical link or optical switch node in the optical network.

36. The optical switch node of claim 34 wherein the controller is configured to further append at least one of:

a burst mode reset to the control information; and

update and/or management information to the control information.