Link aggregation

• US 7,414,985 B1
• Filed: 02/01/2002
• Issued: 08/19/2008
• Est. Priority Date: 02/01/2002
• Status: Active Grant

• Current Assignee: Ciena Corporation
• Original Assignee: Ciena Corporation
• Inventors: Gulati, Neeraj, Curtis, Paul, Tedijanto, Theodore E., Zhang, Helen
• Primary Examiner(s): Pham; Chi H.
• Assistant Examiner(s): MEW, KEVIN D
• Application Number:
  US10/061,995
• Time in Patent Office: 2,391 Days
• Field of Search: 370/255, 370/400, 370/401, 370/410, 370/391, 370/254, 370/230, 370/230.1, 370/231, 370/232, 370/233, 370/235, 370/236, 370/236.1, 370/236.2, 370/352, 370/353, 370/354, 370/355, 370/356, 370/390, 370/392, 370/395.21, 370/396, 370/408, 370/409
• US Class Current: 370/255
• CPC Class Codes: H04J 2203/0053 Routing
• CPC Class Codes: H04J 2203/0067 Resource management and allocation
• CPC Class Codes: H04J 2203/0094 Virtual Concatenation
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/245 Link aggregation, e.g. trunking
• CPC Class Codes: H04L 45/62 Wavelength based optical switching H04Q11/0062
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A method and system for aggregating a plurality of parallel communications links transmitting data between adjacent nodes in a network is provided. The method simplifies network topology by replacing multiple parallel communications links between nodes in the network with a single aggregated link. The method advertises the available bandwidth of each aggregated link to the network, the available bandwidth being the maximum bandwidth available for any one of the parallel links in the aggregate. The method permits each aggregated link to select which of the parallel links in the aggregate is to be used to transfer data from one node to the other. Aggregating links can be automatic and based on one or more predetermined criteria, such as the service class supported by the parallel links.

Claims

1. A method for aggregating a plurality of physical lines connecting adjacent nodes within a network comprising a plurality of nodes, the method comprising:

determining line status information for at least two of said plurality of physical lines connecting adjacent first and second nodes, where said line status information includes information regarding available data transmission bandwidth for transferring data between said adjacent first and said second nodes;

associating at least a first and second of said plurality of physical lines connecting said first and second nodes with one another to create a first aggregated link, wherein said first and second of said plurality of physical lines are associated without affecting traffic;

determining aggregate status information for said first aggregated link;

broadcasting aggregate status information for said first aggregated link to at least one adjacent node and one non-adjacent node, where said first aggregated link includes the maximum data transmission bandwidth available over a one of said plurality of physical lines within said first aggregated link; and

if one of said at least said first and second of said plurality of physical lines fails, performing local span restoration within said first aggregated link;

wherein the network comprises an optical network; and

wherein the method is implemented as one of part of a signaling and routing protocol for the optical network, a sub-network connection client module communicating with the optical network, and combinations thereof.

2. The method of claim 1 further including the step of using a greedy algorithm to assign traffic across said first aggregated link.

3. The method of claim 1 wherein said first aggregate link consists solely of physical lines directly connecting the first node to the second node.

4. The method of claim 3 wherein said first aggregate link consists solely of physical lines directly connecting the first node to the second node, and wherein there are no intermediate nodes between the first node and the second node.

5. The method of claim 1, further comprising the step of associating at least a third of said plurality of physical lines connecting the first node to the second node with a second aggregated link containing line status information on said third physical line.

6. The method of claim 5, wherein said physical lines only include physical lines directly between the first node and the second node and there are no intermediate nodes between the first node and the second node.

7. The method of claim 5, wherein said second aggregate link consists of physical lines having a different class of service than said physical lines in said first aggregate link.

8. The method of claim 1, further comprising the steps:

determining the class of service for said plurality of physical lines connecting the first node to the second node by said status information;

prior to associating physical lines for said first aggregated link, selecting said first and second of said plurality of physical lines to be associated with each other in said first aggregate link from a group of said plurality of physical lines having a first class of service; and

creating a second aggregate link to include at least a third of said plurality of physical lines connecting the first node to the second node having a second class of service different from the first class of service.

9. The method of claim 1 wherein the first node is a sub network connection network element.

10. The method of claim 9 wherein the sub network connection network element is a sub network connection switch.

11. The method of claim 1 comprising the additional step of transmitting the aggregate status information of the first aggregated link to said second node.

12. The method of claim 1 wherein said aggregate status information of said first aggregated link includes a class of service based upon the line status information of each of said plurality of physical lines associated with said first aggregated link.

13. The method of claim 1 further comprising the step of automatically associating at least two of said plurality of said physical lines with the first aggregated link.

14. The method of claim 1 further comprising the step of reassociating one of said plurality of physical lines from the first aggregated link to a second aggregated link without affecting traffic on said one of said plurality of physical lines.

15. The method of claim 1 further comprising the step of designating which of said plurality of physical lines associated with said first aggregated link transmits data to said second node.

16. The method of claim 1 wherein at least one of said plurality of physical lines includes optical fiber.

17. A method for directing information across a plurality of physical lines and switches in a network, the method comprising:

storing line status information from said plurality of physical lines connecting a first switch to a second switch adjacent said first switch, the line status information including at least currently available bandwidth across each of said plurality of physical lines;

grouping at least two of said plurality of physical lines connecting the first switch and the second switch into a first aggregated link without affecting traffic on said at least two of said plurality of physical lines;

storing aggregate status information about the first aggregated link including the currently available bandwidth for a one of said plurality of physical lines within said first aggregated link having the highest currently available bandwidth selected from the line status information for said plurality of physical lines, where said aggregate status information is accessible by remote switches;

receiving a request to send information from said first switch to said second switch, said request including the amount of required bandwidth for the information;

directing the information across said first aggregated link only if said stored aggregate status information includes a currently available bandwidth greater than the required bandwidth for the information; and

if one of said at least two of said plurality of physical lines fails, performing local span restoration within said first aggregated link;

wherein the network comprises an optical network; and

wherein the method is implemented as one of part of a signaling and routing protocol for the optical network, a sub-network connection client module communicating with the optical network, and combinations thereof.

18. The method of claim 17, further comprising:

selecting a physical line from said plurality of physical lines within the first aggregated link by determining a group of physical lines having a currently available bandwidth at least as great as the required bandwidth for the information and selecting an optimal physical line from said determined group having the least currently available bandwidth; and

directing the information across said optimal physical line.

19. The method of claim 17, further comprising:

grouping at least a further two of said plurality of physical lines connecting the first switch and the second switch into a second aggregated link without affecting traffic on said at least said further two of said plurality of physical lines;

storing second aggregate status information about the second aggregated link including the currently available bandwidth for a one of said plurality of physical lines within said second aggregated link having the highest currently available bandwidth selected from the line status information for said plurality of physical lines; and

assigning the plurality of physical lines to the first aggregated link or the second aggregated link by placing physical lines having a first class of service in the first aggregated link and placing physical lines having a second class of service in the second aggregated link, wherein said assigning the plurality of physical lines to the first aggregated link or the second aggregated link is performed without affecting traffic.

20. The method of claim 19, further comprising:

receiving a class of service request within the request to send information between said first switch and said second switch; and

selecting an optimal aggregated link from said first aggregated link and said second aggregated link by selecting an aggregate link that matches the class of service request in said request to send information.

21. The method of claim 20, further comprising:

selecting a physical line from said plurality of physical lines within the optimal aggregated link by determining a group of physical lines having a currently available bandwidth at least as great as the required bandwidth for the information and selecting an optimal physical line from said determined group having the least currently available bandwidth; and

directing the information across said optimal physical line.

22. A method for directing information across a plurality of physical lines and switches in a network, the method comprising:

grouping at least two of said plurality of physical lines connecting a first switch and a second switch adjacent said first switch into a first aggregated link without affecting traffic of said at least two of said plurality of physical lines;

storing aggregate status information accessible by a third switch from said plurality of physical lines connecting a first switch to a second switch, the aggregate status information including at least currently available bandwidth across each of said plurality of physical lines;

receiving a request to send information from said first switch to said second switch, said request including the amount of required bandwidth for the information; and

directing the information across said first aggregated link only if said stored aggregate status information includes a currently available bandwidth greater than the required bandwidth for the information; and

if one of said at least two of said plurality of physical lines fails, performing local span restoration within said first aggregated link;

wherein the network comprises an optical network; and

wherein the method is implemented as one of part of a signaling and routing protocol for the optical network, a sub-network connection client module communicating with the optical network, and combinations thereof.

23. The method of claim 22, further comprising:

selecting a physical line from said plurality of physical lines within the first aggregated link by determining a group of physical lines having a currently available bandwidth at least as great as the required bandwidth for the information and selecting an optimal physical line from said determined group having the least currently available bandwidth; and

directing the information across said optimal physical line.

24. The method of claim 22, further comprising:

grouping at least a further two of said plurality of physical lines connecting the first switch and the second switch into a second aggregated link without affecting traffic on said at least said further two of said plurality of physical lines;

storing second aggregate status information about the second aggregated link including the currently available bandwidth for a one of said plurality of physical lines within said second aggregated link having the highest currently available bandwidth selected from the line status information for said plurality of physical lines;

assigning the plurality of physical lines to the first aggregated link or the second aggregated link by placing physical lines having a first class of service in the first aggregated link and placing physical lines having a second class of service in the second aggregated link.

25. The method of claim 22, further comprising:

receiving a class of service request within the request to send information between said first switch and said second switch; and

selecting an optimal aggregated link from said first aggregated link and said second aggregated link by selecting an aggregate link that matches the class of service request in said request to send information.

26. The method of claim 22 wherein said first aggregate link consists solely of physical lines directly connecting the first node to the second node.

27. The method of claim 22 wherein said first aggregate link consists solely of physical lines directly connecting the first node to the second node, and wherein there are no intermediate nodes between the first node and the second node.

28. A method for directing information across a plurality of physical lines and switches in a network, the method comprising:

grouping at least two of said plurality of physical lines connecting a first of said switches and a second of said switches into a first aggregated link without affecting traffic on said at least two of said plurality of physical lines;

storing aggregate status information from said plurality of physical lines connecting a first switch to a second switch, the aggregate status information including at least currently available bandwidth across each of said plurality of physical lines and the class of service for each of said plurality of physical lines;

receiving a request to send information from said first switch to said second switch, said request including the amount of required bandwidth for the information and the minimum class of service required; and

directing the information across said first aggregated link only if said stored aggregate status information includes a currently available bandwidth greater than the required bandwidth for the information;

selecting a physical line from said plurality of physical lines within the first aggregated link by determining a group of physical lines having a currently available bandwidth at least as great as the required bandwidth for the request and having at least the minimum class of service required by the request;

selecting an optimal physical line from said determined group having the least currently available bandwidth;

directing the information across said optimal physical line; and

if one of said at least two of said plurality of physical lines fails, performing local span restoration within said first aggregated link;

wherein the network comprises an optical network; and

wherein the method is implemented as one of part of a signaling and routing protocol for the optical network, a sub-network connection client module communicating with the optical network, and combinations thereof.