Control architecture in optical burst-switched networks

• US 6,721,315 B1
• Filed: 09/30/1999
• Issued: 04/13/2004
• Est. Priority Date: 09/30/1999
• Status: Expired due to Term

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Alcatel SA (Nokia Corporation)
• Inventors: Cankaya, Hakki C., Vandenhoute, Marc L. J., Xiong, Yijun
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): JONES, PRENELL P
• Application Number:
  US09/409,573
• Time in Patent Office: 1,657 Days
• Field of Search: 370/389-396, 370/222-225, 370/351, 370/338, 370/410-413, 370/397, 370/474, 370/392, 370/471, 370/355, 370/356, 370/390, 359/120-139, 359/121, 359/133, 359/124
• US Class Current: 370/389
• CPC Class Codes: H04L 49/205 Quality of Service based
• CPC Class Codes: H04L 49/254 Centralised controller, i.e. arbitration or scheduling
• CPC Class Codes: H04L 49/30 Peripheral units, e.g. input or output ports
• CPC Class Codes: H04L 49/3009 Header conversion, routing tables or routing tags
• CPC Class Codes: H04Q 11/0066 Provisions for optical burst or packet networks
• CPC Class Codes: H04Q 11/0071 Provisions for the electrical-optical layer interface
• CPC Class Codes: H04Q 2011/002 using optical delay lines or optical buffers or optical recirculation
• CPC Class Codes: H04Q 2011/0064 Arbitration, scheduling or medium access control aspects
• CPC Class Codes: H04Q 2011/0084 Quality of service aspects

Abstract

A control architecture for an optical burst-switched network includes an electronic ingress edge router, a switch control unit at each hop, and an electronic egress edge router. The electronic ingress edge router assembles multiple data packets into a burst. The switch control units at each hop configure the optical switching matrix to switch the burst through the optical burst-switched network. Finally, the electronic egress edge router receives the burst from the optical burst-switched network and disassembles the burst into multiple data packets.

Claims

1. A control system for switching data packets through an optical burst-switched network, comprising:

an electronic ingress edge router operable to assemble a plurality of said data packets into a burst;

a switch control unit at each hop operable to configure an optical switching matrix to switch said burst through said optical burst-switched network; and

an electronic egress edge router operable to receive said burst from said optical burst-switched network and disassemble said burst into said plurality of data packets.

2. The system of claim 1, wherein said electronic ingress edge router is operable to assemble said plurality of data packets into said burst according to each said data packet'"'"'s electronic egress edge router address and the quality of service information in each said data packet.

3. The system of claim 1, wherein said switch control unit at each hop is operable to configure a plurality of fiber delay line optical buffers.

4. The system of claim 1, wherein said data packet is comprised of a data packet header and a data packet payload.

5. The system of claim 1, wherein said burst is comprised of a burst header packet and a burst payload.

6. The system of claim 5, wherein said burst header packet is comprised of routing information and optical burst switching specific information including a synchronization hint which contains hints for the receiving egress edge router synchronization, an offset time specifying the offset time from a first bit of said burst header packet to a first bit of said burst payload, a burst duration specifying the duration of said burst payload, a burst bit rate which gives said bit rate at which said burst payload is transmitted, a data channel identifier specifying an identifier (ID) of said data channel on which said burst payload is sent, said QoS information specifying the quality of service to be received by said burst payload, a burst sequence number identifying said bursts having the same said electronic ingress and egress edge router addresses (said bursts may arrive out of order even if they follow the same path, and a cyclic redundancy check.

7. The system of claim 6, wherein said electronic ingress edge router comprises at least one burst assembly and transmission board operable to receive said plurality of data packets, said burst assembly and transmission board comprising:

a burst assembler operable to assemble said plurality of data packets into said burst according to each said data packet'"'"'s electronic edge router address and each said data packet'"'"'s quality of service information;

a shared memory operable to store said burst;

a burst queue operable to receive and buffer said burst header packet and an address in said shared memory where said burst is stored;

a first scheduler operable to receive said burst header packet and said address of said burst in said shared memory, find the earliest times to transmit said burst header packet and said burst, find associated data channels and control channels to transmit said burst and said burst header packet, respectively, and attach the time to send said burst header packet and said burst, said control channel ID, and said data channel ID to said burst header packet;

a transmission controller operable to receive said burst header packet and said burst address in said shared memory from said first scheduler and to transmit said burst header packet and said burst at said times specified by said first scheduler; and

a burst and burst header packet transmission module operable to receive said burst header packet, said control channel ID, said shared memory burst address, and said data channel ID from said transmission controller, use said shared memory burst address to retrieve said burst from said shared memory, generate said burst payload, and output said burst payload and said burst header packet to the appropriate said data channel and said control channel, respectively.

8. The system of claim 7, wherein said burst assembler comprises:

a packet receiver operable to receive said plurality of data packets and transmit said plurality of data packets to said shared memory for storage;

a processor operable to receive data packet headers of said plurality of data packets from said packet receiver and read said electronic egress router address from each said data packet header and determine which said electronic egress edge router to which each said data packet will be transmitted; and

a plurality of buckets operable to store said shared memory address of each said data packet in a particular said bucket based on each said data packet'"'"'s electronic egress router address and quality of service requirements.

9. The system of claim 8, wherein each said bucket comprises:

a timer operable to record the elapsed time since the first said data packet arrives in said bucket; and

a counter operable to record the number of bytes accumulated in said bucket.

10. The system of claim 7, wherein said burst and burst header packet transmission module comprises:

a plurality of burst transmitters operable to receive said shared memory burst address and said data channel ID from said transmission controller and transmit said burst payload;

a plurality of burst header packet transmitters operable to receive said burst header packet and said control channel ID from said transmission controller and transmit said burst header packet; and

a plurality of electronic to optical converters operable to convert said burst payload or said burst header packet to a pre-specified wavelength.

11. The system of claim 7, wherein said burst assembly and transmission board comprises:

a plurality of said burst assemblers;

a plurality of said burst queues;

said shared memory;

a combined said first scheduler and said transmission controller module; and

said burst and burst header packet transmission module.

12. The system of claim 7, wherein said burst assembly and transmission board comprises:

a plurality of said burst assemblers;

a plurality of said burst queues;

said combined first scheduler and said transmission controller module; and

said burst and burst header packet transmission module.

13. The system of claim 6, wherein said switch control unit comprises:

a plurality of second schedulers operable to;

read the burst payload timing information and said optical burst switching specific information from said burst header packet to determine when said burst payload will arrive at said optical switching matrix and how long said burst payload will last;

determine if any outgoing data channels available are in said optical switching matrix at the time said burst payload is to arrive, either without using any fiber delay line, or using said fiber delay line from said plurality of fiber delay line buffers;

determine the time to send out said burst header packet; and

send configuration information;

a plurality of switch controllers operable to;

receive said configuration information from said scheduler; and

configure said data channels in said switching matrix if any are available; and

a plurality of burst header packet transmission modules operable to read said time to send information from said burst header packet and transmit said burst header packet at the appropriate time on an appropriate said control channel.

14. The system of claim 13, wherein said configuration information includes an incoming said data channel identifier, an outgoing said data channel identifier, a time to switch said burst payload, said burst payload duration, and a fiber delay line identifier specifying which said fiber delay line of said fiber delay line buffers to use.

15. The system of claim 13, wherein said second scheduler comprises:

a scheduling queue operable to store said burst header packet;

a burst header packet processor operable to receive said burst header packet from said scheduling queue, extract said burst payload timing information and said optical burst switching specific information, create said configuration information and modify said burst header packet;

a data channel scheduling module operable to receive said burst payload timing information and said burst payload duration information from said burst header packet processor and search for an idle said outgoing data channel where said burst payload can be transmitted and inform said burst header packet processor when the first bit of said burst payload will leave said optical switching matrix (time-to-leave); and

a control channel scheduling module operable to receive said burst payload time-to-leave information from said burst header packet processor and select a time to send said burst header packet to an outbound control channel group.

16. The system of claim 13, wherein said switch controller comprises:

a time slot calculation processor operable to;

receive said configuration information from said second scheduler;

convert said configuration information into a format that said switch controller can understand; and

calculate said appropriate time slot (ts) to configure said optical switching matrix according to the following formula;

17. The system of claim 13, wherein said burst header packet transmission module comprises a plurality of said time slots and a second time slot pointer operable to point to a current transmission time slot, each said time slot comprising:

a flag operable to indicate if there is said burst header packet in said time slot to be transmitted; and

a pointer which points to an address of said burst header packet when said flag is equal to one (1).

18. The system of claim 1, wherein said electronic egress edge router comprises:

a plurality of burst header packet receivers operable to read said burst header packet and set said burst payload timing information;

a plurality of said fiber delay lines operable to delay said burst payload;

a plurality of burst receivers operable to receive a signal from said burst header packet receiver informing said burst receiver when and how to receive said burst payload from said fiber delay line; and

a plurality of burst disassemblers operable to disassemble said burst into said plurality of data packets.

42. The system of claim 5, wherein said burst header packet and said burst payload are separately transmitted and switched.

19. A method for switching data packets through an optical burst-switched network, comprising the steps of:

assembling a plurality of data packets into a burst at an electronic ingress edge router;

using a switch control unit to configure an optical switching matrix;

switching said burst through said optical burst-switched network; and

disassembling said burst into said plurality of data packets at an electronic egress edge router.

20. The method of claim 19, wherein said switch control unit is further operable to configure a plurality of fiber delay line optical buffers.

21. The method of claim 19, wherein said data packet is comprised of a data packet header and a data packet payload.

22. The method of claim 19, wherein said burst is comprised of a burst header packet and a burst payload.

23. The method of claim 22, wherein said burst header packet is comprised of routing information and optical burst switching specific information including a synchronization hint which contains hints for the receiving egress edge router synchronization, an offset time specifying said offset time from a first bit of said burst header packet to a first bit of said burst payload, a burst duration specifying the duration of said burst payload, a burst bit rate which gives said bit rate at which said burst payload is transmitted, a data channel identifier specifying an identifier (ID) of said data channel on which said burst payload is sent, a QoS information specifying the quality of service to be received by said burst payload, a burst sequence number identifying said bursts having the same said electronic ingress and egress edge router addresses (said bursts may arrive out of order even if they follow the same path, and a cyclic redundancy check.

26. The method of claim 19, wherein said optical switching matrix is configured, comprising the steps of:

reading said burst payload timing information and said optical burst switching information from said burst header packet at a first scheduler to determine when said burst payload will arrive at said optical switching matrix and how long said burst payload will last;

determining if any outgoing data channels available are in said optical switching matrix at the time said burst payload is to arrive, either without using any said fiber delay line, or using said fiber delay line from a plurality of said fiber delay line buffers;

transmitting said outgoing data channel configuration information to a switch controller if any said outgoing data channels are available;

calculating a time slot to configure said optical switching matrix and said fiber delay line optical buffers based on said outgoing data channel configuration information; and

configuring said optical switching matrix and said fiber delay line optical buffers at said time slot.

27. The method of claim 19, wherein said burst is disassembled into said plurality of data packets comprising the steps of:

receiving said burst header packet at a burst header packet receiver;

reading said burst header packet and set said burst payload timing information;

receiving said burst payload at a fiber delay line;

receiving a signal at a burst receiver from said burst header packet receiver informing said burst receiver when and how to receive said burst payload from said fiber delay line;

receiving said burst payload at a burst disassembler; and

disassembling said burst payload into said plurality of data packets.

28. The method of claim 19, wherein said electronic ingress edge router comprises a plurality of burst assembly and transmission boards operable to receive said plurality of data packets, said burst assembly and transmission board comprising:

a burst assembler operable to assemble said plurality of data packets into said burst according to each said data packet'"'"'s electronic edge router address and each said data packet'"'"'s quality of service information;

a shared memory operable to store said burst;

a burst queue operable to receive and buffer said burst header packet and an address in said shared memory where said burst is stored;

a first scheduler operable to receive said burst header packet and said address of said burst in said shared memory, find the earliest times to transmit said burst header packet and said burst, find associated data channels and control channels to transmit said burst and said burst header packet, respectively, and attach the time to send said burst header packet and said burst, said control channel ID, and said data channel ID to said burst header packet;

a transmission controller operable to receive said burst header packet and said burst address in said shared memory from said first scheduler and to transmit said burst header packet and said burst at said times specified by said first scheduler; and

a burst and burst header packet transmission module operable to receive said burst header packet, said control channel ID, said shared memory burst address, and said data channel ID from said transmission controller, use said shared memory burst address to retrieve said burst from said shared memory, generate said burst payload, and output said burst payload and said burst header packet to the appropriate said data channel and said control channel, respectively.

29. The method of claim 28, wherein said burst assembler comprises:

said packet receiver operable to receive data packet headers of said plurality of data packets and transmit said plurality of data packets to said shared memory for storage;

a processor operable to receive said plurality of data packets from said packet receiver and read said electronic egress router address from each said data packet header and determine which said electronic egress edge router each said data packet will be transmitted to; and

a plurality of buckets operable to store said shared memory address of each said data packet in a particular said bucket based on each said data packet'"'"'s electronic egress router address.

30. The method of claim 29, wherein each said bucket comprises:

a timer operable to record the elapsed time since the first said data packet arrives in said bucket; and

a counter operable to record the number of bytes accumulated in said bucket.

31. The method of claim 28, wherein said burst and burst header packet transmission module comprises:

a plurality of burst transmitters operable to receive said shared memory burst address and said data channel ID from said transmission controller, output said burst payload on said data channel;

a plurality of burst header packet transmitters operable to receive said burst header packet and said control channel ID from said transmission controller, output said burst header packet on said control channel; and

a plurality of electronic to optical converters operable to convert said burst payload or said burst header packet to a pre-specified wavelength.

32. The method of claim 28, wherein said burst assembly and transmission board comprises:

a plurality of said burst assemblers;

a plurality of said burst queues;

said shared memory;

a combined first scheduler and said transmission module; and

said burst and burst header packet transmission module.

33. The method of claim 28, wherein said burst assembly and transmission board comprises:

a plurality of said burst assemblers;

a plurality of said burst queues;

said combined first scheduler and said transmission module; and

said burst and burst header packet transmission module.

34. The method of claim 23, wherein said switch control unit comprises:

said plurality of second schedulers operable to;

read said burst payload timing information and said optical burst switching specific information from said burst header packet to determine when said burst payload will arrive at said optical switching matrix and how long said burst payload will last;

determine if any outgoing data channels available are in said optical switching matrix at the time said burst payload is to arrive, either without using any fiber delay line, or using said fiber delay line from said plurality of fiber delay line buffers;

determine said time to send said burst header packet; and

send configuration information;

a plurality of switch controllers operable to;

receive said configuration information from said scheduler; and

configure said data channels in said switching matrix if any are available; and

a plurality of burst header packet transmission modules operable to read said time to send information from said burst header packet and transmit said burst header packet at the appropriate time on an appropriate control channel.

35. The method of claim 34, wherein said configuration information includes an incoming said data channel identifier, an outgoing said data channel identifier, a time to switch said burst payload, said burst payload duration, and a fiber delay line identifier specifying which said fiber delay line of said fiber delay line buffers to use.

36. The method of claim 34, wherein said second scheduler comprises:

a scheduling queue operable to store said burst header packet;

a burst header packet processor operable to receive said burst header packet from said scheduling queue, extract said burst payload timing information and said optical burst switching specific information, create said configuration information and modify said burst header packet;

a data channel scheduling module operable to receive said burst payload timing information and said burst payload duration information from said burst header packet processor and search for an idle said outgoing data channel where said burst payload can be transmitted and inform said burst header packet processor when the first bit of said burst payload will leave said optical switching matrix (time-to-leave); and

a control channel scheduling module operable to receive said burst payload time-to-leave information from said burst header packet processor and select a time to send said burst header packet to an outbound control channel group.

37. The method of claim 34, wherein said switch controller comprises:

a time slot calculation processor operable to;

receive said configuration information from said second scheduler; and

convert said configuration information into a format that said switch controller can understand; and

calculate said appropriate time slot (ts) to configure said optical switching matrix according to the following formula;

38. The method of claim 34, wherein said burst header packet transmission module comprises:

a flag operable to indicate if there is said burst header packet in said time slot to be transmitted; and

a pointer which points to an address of said burst header packet when said flag is equal to one (1).

39. The method of claim 19, wherein said electronic egress edge router comprises:

said plurality of burst header packet receivers operable to read said burst header packet and set burst payload timing information from said burst header packet;

said plurality of said fiber delay lines operable to delay said burst payload;

said plurality of burst receivers operable to receive a signal from said burst header packet receiver informing said burst receiver when and how to receive said burst payload from said fiber delay line; and

said plurality of burst disassemblers operable to disassemble said burst into said plurality of data packets.

43. The method of claim 22, wherein said burst header packet and said burst payload are separately transmitted and switched.

24. The method of 19, wherein said plurality of data packets are assembled into said bursts according to each said data packet'"'"'s electronic edge router address and/or each said data packet'"'"'s quality of service information.

25. The method of 19, wherein said plurality of data packets are assembled into said burst at said electronic ingress edge router, comprising the steps of:

receiving said plurality of data packets at a packet receiver;

transmitting said plurality of data packets to a shared memory for storage;

reading said electronic egress edge router address and said quality of service information from each said data packet header;

determining which said electronic egress edge router to which each said data packet will be transmitted; and

storing said shared memory address of each data packet in a bucket based on each said data packet'"'"'s electronic egress router address and quality of service information forming said burst.

40. A method for managing an offset-time (τ

) between a burst header packet and its corresponding burst payload during transmission between hops, comprising the steps of;

setting an initial offset-time τ

₀;

resynchronizing said burst payload and said burst header packet at each hop so said offset-time (τ

) is kept as close to said initial offset-time τ

₀ as possible; and

using a departure time of said burst payload from said optical switching matrix rather than an actual switching time of said burst payload inside said optical switching matrix as a reference time to schedule the transmission of said burst header packet on said outgoing control channel group to guard any portion of said burst payload from being cut.

41. A burst assembler mechanism, comprising:

a packet receiver operable to receive a plurality of data packets from a first switch and transmit said plurality of data packets to a shared memory for storage;

a processor operable to receive data packet headers of said plurality of data packets from said packet receiver and read an electronic egress router address and quality of service information from each said data packet headers and determine which said electronic egress edge router each said data packet will be transmitted to; and

a plurality of buckets operable to store said shared memory address of each data packet in a particular said bucket based on each said data packet'"'"'s electronic egress router address and quality of service information.