MULTI-CHASSIS ROUTER WITH MULTIPLEXED OPTICAL INTERCONNECTS

• US 20080044181A1
• Filed: 08/01/2007
• Published: 02/21/2008
• Est. Priority Date: 08/21/2006
• Status: Active Grant

• Current Assignee: Juniper Networks Incorporated
• Original Assignee: Juniper Networks Incorporated
• Inventors: Sindhu, Pradeep
• Granted Patent: US 8,050,559 B2
• Time in Patent Office: Days
• US Class Current: 398/49
• 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 14/0241 Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths
• CPC Class Codes: H04J 14/0257 Wavelength assignment algorithms
• CPC Class Codes: H04J 14/0267 Optical signaling or routing
• CPC Class Codes: H04J 14/028 WDM bus architectures
• CPC Class Codes: H04L 45/62 Wavelength based optical switching H04Q11/0062
• CPC Class Codes: H04L 49/101 using crossbar or matrix
• CPC Class Codes: H04L 49/102 using shared medium, e.g. bus or ring
• CPC Class Codes: H04L 49/25 Routing or path finding in a switch fabric
• CPC Class Codes: H04L 49/40 Constructional details, e.g. power supply, mechanical construction or backplane
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 2011/0039 Electrical control
• CPC Class Codes: H04Q 2011/0052 Interconnection of switches

Abstract

A multi-chassis network device includes a plurality of nodes that operate as a single device within the network and a switch fabric that forwards data plane packets between the plurality of nodes. The switch fabric includes a set of multiplexed optical interconnects coupling the nodes. For example, a multi-chassis router includes a plurality of routing nodes that operate as a single router within a network and a switch fabric that forwards packets between the plurality of routing nodes. The switch fabric includes at least one multiplexed optical interconnect coupling the routing nodes. The nodes of the multi-chassis router may direct portions of the optical signal over the multiplexed optical interconnect to different each other using wave-division multiplexing.

Claims

1. A multi-chassis router comprising:

a plurality of routing nodes that operate as a single router within a network; and

a switch fabric that forwards packets between the plurality of routing nodes, wherein the switch fabric includes at least one multiplexed optical interconnect coupling the routing nodes.

2. The multi-chassis router of claim 1, wherein the multiplexed optical interconnect includes optical taps that distribute an optical signal from a transmitting one of the routing node to the other routing nodes.

3. The multi-chassis router of claim 2, wherein the optical taps distribute substantially equal portions of the optical signal from the transmitting routing node to each of the other routing nodes.

4. The multi-chassis router of claim 1,

wherein the multi-chassis router has N routing nodes, and

wherein the multiplexed optical interconnect is one of a set of N multiplexed optical interconnects, wherein the set of N multiplexed optical interconnects includes a multiplexed optical interconnect coupled to a respective one of the N plurality of routing nodes.

5. The multi-chassis router of claim 4,

wherein the switch fabric has M stages,

wherein the set of N multiplexed optical interconnects is a first set of N multiplexed optical interconnects,

wherein the multi-chassis router includes a total of (M−

1) sets of N multiplexed optical interconnects.

6. The multi-chassis router of claim 4, wherein each of plurality of nodes includes an output that sends signals over one of the set of multiplexed optical interconnects to the remainder of the plurality of nodes.

7. The multi-chassis router of claim 1, wherein the switch fabric is a multi-stage switch fabric and the multiplexed optical interconnect provides a connection between at least two stages in the multi-stage switch fabric.

8. The multi-chassis router of claim 1, wherein each of the routing nodes of the plurality of routing nodes include a filter to isolate a different wavelength of an optical signal transmitted via the optical interconnect.

9. The multi-chassis router of claim 1, wherein the plurality of routing nodes comprises line card chassis.

10. The multi-chassis router of claim 1, wherein the switch fabric is a multi-stage switch fabric, and wherein each node includes a portion of each stage in the multi-stage switch fabric.

11. The multi-chassis router of claim 10,

wherein the multiplexed optical interconnect includes a plurality of fiber optic cables, and

wherein the plurality of fiber-optic cables provide connections between the portions of each stage in the multi-stage switch fabric.

12. The multi-chassis router of claim 1, wherein a transmitting one of the routing nodes outputs an optical signal to the other routing nodes via the multiplexed optical interconnect using wave-division multiplexing, time-division multiplexing or code-division multiplexing.

13. The multi-chassis router of claim 1, wherein each routing node comprises:

a first optical emitter that emits a multiplexed optical signal for forwarding packets from a first stage of the switch fabric to a second stage; and

a second optical emitter that emits a multiplexed optical signal for forwarding packets from a second stage of the switch fabric to a third stage.

14. The multi-chassis router of claim 13, wherein the multiplexed optical interconnect is arranged in a circle within an interior of the multi-chassis router to interconnect the switch fabric.

15. The multi-chassis router of claim 1, wherein the routing nodes of the multi-chassis router are arranged in a substantially circular layout.

16. The multi-chassis router of claim 1, wherein each of the routing nodes has a chassis having a substantially trapezoidal shape.

17. The multi-chassis router of claim 1, wherein the nodes are configured such that the nodes substantially form a circle when interconnected.

18. The multi-chassis router of claim 1, wherein nodes are located in a less-than-full-circle configuration including a gap that provides access to a center of the multi-chassis router.

19. The multi-chassis router of claim 1, wherein the packet is a fixed-length data unit.

20. The multi-chassis router of claim 1, wherein the packet is a variable-length data unit.

21. A multi-chassis router comprising:

a plurality of N routing nodes that operate as a single router within a network;

an M-stage switch fabric that forwards packets between the plurality of routing nodes; and

N*(M−

1) multiplexed point-to-point data interconnects coupling the data planes of routing nodes via the switch fabric.

22. The multi-chassis router of claim 21, wherein each of the multiplexed interconnects carries an optical signal from a transmitting one of the routing nodes to the N−

1 remaining routing nodes.

23. A fiber-optic cable for connecting a plurality of routing nodes in a multi-chassis router comprising:

a cable input to receive an optical signal from a first routing node of the plurality of routing nodes; and

a plurality of optical taps to output a portion of the optical signal to each of the remaining routing nodes,

wherein the plurality of optical taps divide an optical power of the optical signal substantially equally among the remainder of the plurality of routing nodes.

24. The fiber-optic cable of claim 23, further comprising a plurality of wavelength filters to filter the divided optical signal the optical taps.

25. The fiber-optic cable of claim 24, wherein each of the plurality of wavelength filters isolates a different wavelength.

26. A set of fiber-optic cables to interconnect N network devices, the set of fiber-optic cables comprising:

N fiber-optic cables, wherein N is an integer greater than or equal to 2,

wherein each of the N fiber-optic cables includes an input for receiving an optical signal from a first one of the N network devices, and N−

1 optical taps for outputting the optical signal to the N−

1 remaining network devices,

wherein the N−

1 optical taps divide the optical signal to output substantially equal portions of the optical signal to the N−

1 remaining network devices.

27. The set of fiber-optic cables of claim 26, wherein each of the N fiber-optic cables further includes wavelength filters to filter the divided optical signal from the optical taps.

28. The set of fiber-optic cables of claim 27, wherein each of the wavelength filters in one of the N fiber-optic cables isolates a different wavelength.

29. The set of fiber-optic cables of claim 26, wherein N is selected from the set of 4, 16 or 32.

30. A method comprising:

receiving a packet at one of a plurality of routing nodes of a multi-chassis router;

selecting a wavelength based on information within the packet, wherein the wavelength corresponds to one of the routing nodes within the multi-chassis router;

transmitting the packet via an optical signal having the selected wavelength from a first one of the routing nodes of the multi-chassis router to a second one of the routing nodes via a switch fabric having an optical interconnect.

31. The method of claim 30, further comprising:

receiving portions of the optical signal with at least two other routing nodes of the multi-chassis router; and

filtering the portions of the optical signal to isolate wavelengths for the receiving routing nodes.

32. The method of claim 30, wherein the optical signal incorporates wavelength division multiplexing (WDM).

33. The method of claim 30, wherein the switch fabric is a data plane switch fabric.

34. The method of claim 30, wherein the data packet is a fixed-length data packet.

35. A network device comprising:

a plurality of forwarding nodes coupled to a plurality of devices within a network; and

a set of multiplexed optical interconnects coupling the forwarding nodes to each other.

36. The network device of claim 35, wherein each of plurality of forwarding nodes includes an output that sends signals over a single one of the multiplexed optical interconnects to the remainder of the plurality of forwarding nodes.

37. The network device of claim 35, wherein the network device is a switch or a router.

38. A system comprising:

a plurality of network devices coupled to a network; and

a multi-chassis network device connecting the plurality of network devices on the network, wherein the multi-chassis network device includes;

a plurality of nodes that operate as a single device within the network, and

a switch fabric that forwards data plane packets between the plurality of nodes, wherein the switch fabric includes a set of multiplexed optical interconnects coupling the nodes.

39. The system of claim 38, wherein the plurality of nodes includes N nodes, wherein the switch fabric includes M stages, wherein the set of multiplexed optical interconnects includes N*(M−

1) cables.

40. The system of claim 38, wherein the system is a data center.