METHODS AND APPARATUSES FOR PATH SELECTION IN A PACKET NETWORK

• US 20120120951A1
• Filed: 11/12/2010
• Published: 05/17/2012
• Est. Priority Date: 11/12/2010
• Status: Active Grant

• Current Assignee: Tellabs Operations Incorporated (Infinera Corp.)
• Original Assignee: Tellabs Operations Incorporated (Infinera Corp.)
• Inventors: Richmond, Mark A., Kangas, Bradley R., Mathew, Anoop J., Harpalani, Jai, Turner, James N., Mizialko, Kenneth S.
• Granted Patent: US 9,178,804 B2
• Time in Patent Office: Days
• US Class Current: 370/390
• CPC Class Codes: H04L 45/125 based on throughput or bandwidth
• CPC Class Codes: H04L 45/24 Multipath
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04Q 2213/13003 Constructional details of switching devices
• CPC Class Codes: H04Q 2213/1301 Optical transmission, optical switches
• CPC Class Codes: H04Q 2213/1302 Relay switches
• CPC Class Codes: H04Q 2213/1304 Coordinate switches, crossbar, 4/2 with relays, coupling field
• CPC Class Codes: H04Q 2213/13166 Fault prevention
• CPC Class Codes: H04Q 2213/13292 Time division multiplexing, TDM
• CPC Class Codes: H04Q 2213/1336 Synchronisation
• CPC Class Codes: H04Q 3/54558 Redundancy, stand-by

Abstract

Embodiments including methods, systems, and apparatuses for distributing, processing, and reacting to path information distributed via a service-agnostic packet fabric for the purpose of enabling path selection are disclosed. By configuring two ingress line cards to send path quality words to each other via the switch fabric, compare the path quality words, and determine whether to transmit traffic to an egress line card via the switch fabric based on the comparison of the path quality words, the embodiments enable a central switch fabric to be unaware of the paths that it carries, and enable both ingress and egress bandwidth of the switch fabric to be sized according to the facilities for which it is terminating. The switch fabric does not need to support working and protection paths simultaneously in some embodiments, allowing it to be scaled appropriately to termination facilities.

Claims

1. A switching domain, comprising:

a switch fabric; and

first and second ingress line cards configured to (i) send path quality words to each other via the switch fabric, (ii) compare the path quality words, and (iii) determine whether to transmit traffic to a third line card via the switch fabric based on the comparison of the path quality words.

2. A switching domain as in claim 1 wherein the path quality words represent quality of received ingress traffic.

3. A switching domain as in claim 1 wherein the first and second ingress line cards are further configured to multicast their respective path quality words to all line cards in the switching domain.

4. A switching domain as in claim 1 wherein the switching domain is configured to have either of the first or second line cards transmit traffic for a protected path, and wherein the first and second line cards are each further configured to determine independently whether to transmit traffic based on whether the path quality word it sent represents a higher path quality than the path quality word sent by the other of the first and second line cards.

5. A switching domain as in claim 1 wherein the first and second line cards are each further configured to transmit traffic for a protected path if a path quality word is not received from the other of the first and second line cards within a predetermined interval.

6. A switching domain as in claim 1 wherein the first and second ingress line cards are each configured to squelch its traffic based on the determination of whether to transmit traffic.

7. A switching domain as in claim 1 wherein the third line card is configured to accept traffic from the first or second ingress line cards.

8. A switching domain as in claim 1 wherein the first and second ingress line cards are further configured to batch multiple path quality words together before sending the batched path quality words to each other via the switch fabric.

9. A switching domain as in claim 8 wherein the first and second ingress line cards are further configured to extract path quality words from a message including multiple path quality words.

10. An ingress line card in a switching domain, the ingress line card comprising:

a message generator configured to generate a local path quality word and to send the local path quality word to a remote ingress line card via a switch fabric; and

a comparator configured to compare the local path quality word to a remote path quality word received from the remote ingress line card and to determine whether to transmit traffic based on a comparison of the local and remote path quality words.

11. An ingress line card as in claim 10 wherein the local path quality word represents the quality of received ingress traffic at the ingress line card for a given protected path, and the remote path quality word represents the quality of received ingress traffic at the remote ingress line card for the given protected path.

12. An ingress line card as in claim 10 wherein the ingress line card is configured to multicast the local path quality word to all line cards in operative communication with the switch fabric.

13. An ingress line card as in claim 10 wherein the ingress line card is configured to determine independently whether to transmit traffic for a protected path based on whether the local path quality word represents a higher path quality than the remote path quality word.

14. An ingress line card as in claim 10 wherein the ingress line card is configured to transmit traffic for a protected path if the remote path quality word is not received from the remote line card within a predetermined interval.

15. An ingress line card as in claim 10 wherein the message generator is further configured to generate a message with multiple local path quality words to be sent to the remote ingress line card.

16. An ingress line card as in claim 15 wherein the comparator is further configured to extract path quality words from a message including multiple path quality words.

17. A method of switching traffic, the method comprising:

generating a local path quality word;

sending the local path quality word to a remote ingress line card via a switch fabric;

comparing the local path quality word to a remote path quality word received from the remote ingress line card; and

determining whether to transmit traffic based on the comparison of the local and remote path quality words.

18. A method as in claim 17 wherein generating a local path quality word includes generating a local path quality word representing the quality of received ingress traffic.

19. A method as in claim 17 wherein sending the local path quality word includes multicasting the local path quality word to all line cards in operative communication with the switch fabric.

20. A method as in claim 17 wherein determining whether to transmit traffic includes independently determining whether to transmit traffic based on whether the local path quality word represents a higher path quality than the remote path quality word.

21. A method as in claim 17 wherein determining whether to transmit traffic includes transmitting traffic if the remote path quality word is not received from the remote line card within a predetermined interval.

22. A method as in claim 17 wherein determining whether to transmit traffic includes squelching traffic.

23. A method as in claim 17 wherein sending the local path quality word includes batching the local path quality word together with other local path quality word before sending.

24. A method as in claim 23 wherein comparing the local and remote path quality words includes extracting the remote path quality word from a message including other remote path quality words.

25. A switch fabric, comprising:

a table configured with entries representing addresses of line cards; and

a replicator configured to replicate packets containing path quality words with respective source addresses and to transmit the replicated packets to the line cards according to the entries in the table.

26. A switch fabric as in claim 25 wherein (i) the table is multicast table and (ii) the replicator is further configured to multicast the replicated packets to the line cards according to the entries in the multicast table.

27. A switch fabric as in claim 25 wherein at least some packets include multiple parts, each part including a source address and one or more path quality word.

28. A line card in a switching domain, comprising:

a table having entries representing source addresses of local ingress paths on which local traffic can be received; and

an associator configured to generate, based on the table, a message packet with an entry and a path quality word, and configured to transmit the message packet into a line card message stream to be transmitted to a switch fabric known to be configured to inspect the message packet and direct the message packet to at least one other line card corresponding to the entry in the message packet.

29. A line card as in claim 28 wherein the entry of the message packet is a multicast address.

30. A line card as in claim 28 wherein message packets include multiple parts, each part including a source address and a path quality word.

31. A line card, comprising:

a table configured with entries representing source addresses of local and remote protection paths; and

a comparison module configured to compare path quality words representing qualities of local and remote protected paths and configured to cause a local traffic transmission module to enable or disable transmission of received local traffic based on the comparison and the entries of the table.