System and method for router arbiter protection switching
First Claim
1. A method of protection switching of redundant central arbiters in a router system, comprising:
- selecting an active central arbiter;
selecting a standby central arbiter different from said active central arbiter;
communicating the active status of said active central arbiter;
communicating the standby status of said standby central arbiter;
receiving at said active central arbiter requests to pass chunks of data through an optical switching fabric;
at said active central arbiter in response to said requests concurrently issuing grants to pass said chunks and issuing optical switch configuration information corresponding to said grants, such that each said chunk passes during a single chunk period;
at said standby central arbiter periodically receiving keep-alive requests;
at said standby central arbiter concurrently issuing keep-alive grants and standby configuration information in response to said keep-alive requests; and
interchanging said active and standby status of said respective active and standby central arbiters, such that said standby central arbiter becomes a new active central arbiter and said active central arbiter becomes a new standby central arbiter;
wherein decisions of said selecting and said interchanging are initiated by a control processor selected from the group consisting of a master control processor (MCP) and shelf control processors, wherein said communicating of said active status occurs simultaneously from said active central arbiter to an optical switch ASIC and to a plurality of ingress ASICs; and
said communicating of said standby status occurs simultaneously from said standby central arbiter to an optical switch ASIC and to a plurality of ingress ASICs, wherein said issuing grants and said issuing corresponding switch configuration information both occur within the same chunk period, wherein said issuing keep-alive grants and said issuing standby configuration information both occur within the same chunk period, wherein said requests received by said active central arbiter are issued from a plurality of ingress ASICs through first multiple links, wherein said grants issued by said active central arbiter are received by said plurality of ingress ASICs through said first multiple links, and wherein, if a grant is not received by said ingress ASIC within a predetermined timeout period after the corresponding request was issued, then said ingress ASIC resets an internal outstanding request queue as well as request queues in said active central arbiter, until the respective queues of both said ingress ASIC and said active central arbiter are emptied of all outstanding requests, such that said ingress ASIC and said active central arbiter are synchronized in an empty state.
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Accused Products
Abstract
In a router with redundant central arbiters, a set of control processors (CPs) determines which arbiter is active, which is standby, and when to switch between them. In normal operation ingress ASICs issue requests to the active central arbiter ASIC and keep-alive requests cyclically once per chunk period to the passive arbiter ASIC, which then returns keep-alive grants through the same links to the ingress ASICs and sends standby configuration information to the optical switch ASICs. The arbiter ASICs pass a switch-over decision simultaneously to the optical switch ASICs and ingress ASICs, which empty all queues of outstanding requests, and then resend all of those requests to the new active central arbiter after all queues are empty, such that no router traffic is lost. Mechanisms ensure that during the transition the ASICs properly recognize which data links are healthy and which arbiter is active.
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Citations
12 Claims
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1. A method of protection switching of redundant central arbiters in a router system, comprising:
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selecting an active central arbiter; selecting a standby central arbiter different from said active central arbiter; communicating the active status of said active central arbiter; communicating the standby status of said standby central arbiter; receiving at said active central arbiter requests to pass chunks of data through an optical switching fabric; at said active central arbiter in response to said requests concurrently issuing grants to pass said chunks and issuing optical switch configuration information corresponding to said grants, such that each said chunk passes during a single chunk period; at said standby central arbiter periodically receiving keep-alive requests; at said standby central arbiter concurrently issuing keep-alive grants and standby configuration information in response to said keep-alive requests; and interchanging said active and standby status of said respective active and standby central arbiters, such that said standby central arbiter becomes a new active central arbiter and said active central arbiter becomes a new standby central arbiter; wherein decisions of said selecting and said interchanging are initiated by a control processor selected from the group consisting of a master control processor (MCP) and shelf control processors, wherein said communicating of said active status occurs simultaneously from said active central arbiter to an optical switch ASIC and to a plurality of ingress ASICs; and said communicating of said standby status occurs simultaneously from said standby central arbiter to an optical switch ASIC and to a plurality of ingress ASICs, wherein said issuing grants and said issuing corresponding switch configuration information both occur within the same chunk period, wherein said issuing keep-alive grants and said issuing standby configuration information both occur within the same chunk period, wherein said requests received by said active central arbiter are issued from a plurality of ingress ASICs through first multiple links, wherein said grants issued by said active central arbiter are received by said plurality of ingress ASICs through said first multiple links, and wherein, if a grant is not received by said ingress ASIC within a predetermined timeout period after the corresponding request was issued, then said ingress ASIC resets an internal outstanding request queue as well as request queues in said active central arbiter, until the respective queues of both said ingress ASIC and said active central arbiter are emptied of all outstanding requests, such that said ingress ASIC and said active central arbiter are synchronized in an empty state. - View Dependent Claims (2, 3, 4)
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5. A method of protection switching of redundant central arbiters in a router system, comprising:
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selecting an active central arbiter; selecting a standby central arbiter different from said active central arbiter; communicating the active status of said active central arbiter; communicating the standby status of said standby central arbiter; receiving at said active central arbiter requests to pass chunks of data through an optical switching fabric; at said active central arbiter in response to said requests concurrently issuing grants to pass said chunks and issuing optical switch configuration information corresponding to said grants, such that each said chunk passes during a single chunk period; at said standby central arbiter periodically receiving keep-alive requests; at said standby central arbiter concurrently issuing keep-alive grants and standby configuration information in response to said keep-alive requests; interchanging said active and standby status of said respective active and standby central arbiters, such that said standby central arbiter becomes a new active central arbiter and said active central arbiter becomes a new standby central arbiter; wherein decisions of said selecting and said interchanging are initiated by a control processor selected from the group consisting of a master control processor (MCP) and shelf control processors, wherein; said communicating of said active status occurs simultaneously from said active central arbiter to an optical switch ASIC and to a plurality of ingress ASICs; and said communicating of said standby status occurs simultaneously from said standby central arbiter to an optical switch ASIC and to a plurality of ingress ASICs, wherein said issuing grants and said issuing corresponding switch configuration information both occur within the same chunk period, wherein said issuing keep-alive grants and said issuing standby configuration information both occur within the same chunk period, wherein said requests received by said active central arbiter are issued from a plurality of ingress ASICs through first multiple links, wherein said grants issued by said active central arbiter are received by said plurality of ingress ASICs through said first multiple links, wherein said optical switch configuration information is issued by said active central arbiter to said optical switching fabric through second multiple links differing from said first multiple links, wherein said optical switch configuration information is issued by an active central arbiter ASIC in said active central arbiter to an optical switch ASIC in said optical switching fabric, wherein said keep-alive requests received by said standby central arbiter are issued from a plurality of ingress ASICs through third multiple links differing from said first and second multiple links, wherein said keep-alive grants issued by said standby central arbiter are received by said plurality of ingress ASICs through said third multiple links differing from said first and second multiple links, wherein said standby configuration information is issued by said standby central arbiter to said optical switching fabric through fourth multiple links differing from said first, second, and third multiple links, wherein said standby configuration information is issued by a standby central arbiter ASIC in said standby central arbiter to an optical switch ASIC in said optical switching fabric, wherein the issuing of said keep-alive requests and the receiving of said keep-alive grants by said ingress ASICs is performed cyclically; encoding grants, requests, keep-alive grants, keep-alive requests, optical switch configuration information, standby configuration information, and active or standby status communication messages with error detection codes; sending said grants, requests, keep-alive grants, keep-alive requests, optical switch configuration information, standby configuration information, and arbiter active or standby status bit messages with error detection codes to destinations through multiple links selected from the group consisting of said first, second, third, and fourth multiple links; within each chunk period at said destinations receiving said messages and decoding said error detection codes to determine a healthy or weak state of said multiple links; and within each chunk period intercomparing said determinations among a plurality of said destinations to decide whether to interchange the active or standby status of said central arbiters. - View Dependent Claims (6, 7, 8, 9, 10, 11)
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12. A communication network router incorporating a system for central arbitration protection, said system comprising:
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redundant interchangeable central arbiters including an active central arbiter and a standby central arbiter; a plurality of control processors including a master control processor and distributed control processors, said control processors being interconnected with one another and with said redundant central arbiters through a control network; a plurality of ingress ASICs interconnected through first multiple links with said active central arbiter and through third multiple links with said standby central arbiter; an optical switching fabric containing an optical switch ASIC interconnected through second multiple links with said active central arbiter and through fourth multiple links with said standby central arbiter; said standby central arbiter configured to receive keep-alive requests and send keep-alive grants cyclically through said third multiple links, and to send standby configuration information through said fourth multiple links in response to said keep-alive requests; said redundant central arbiters being configured to interchange in response to a switch over decision from said plurality of control processors, such that said standby central arbiter becomes a new active central arbiter and said active central arbiter becomes a new standby central arbiter, such that said ingress ASICs reset request queues within said ingress ASICs and within said redundant central arbiters, and such that the active and standby status of respective redundant central arbiters is communicated through said first through said fourth multiple links; and said ingress ASICs and said optical switch ASICs being configured to cooperatively determine a healthy or weak state of each of respective first through fourth multiple links and said active and standby status of said respective redundant central arbiters.
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Specification