METHOD AND APPARATUS FOR REDUCING FLOOD TRAFFIC IN SWITCHES
First Claim
1. A method for limiting the flooding of unicast traffic on one or more logical network segment (LNS) operatively coupled with a switching device said switching device comprising one or more ports each said port capable of operatively coupling one or more of said LNSs and said switching device, said switching device capable of bridging and filtering data frames between said operatively coupled LNSS, said method comprising:
- (i) identifying and selecting one or more limited flooding logical network segment (LFLNS) selected from the group consisting of said LNSs operatively coupled to said switching device wherein (a) a selected LFLNS has a predetermined maximum number of device addresses expected to be concurrently operatively associated with said LFLNS and (b) said method is to be utilized on said LFLNS;
(ii) for one or more first LFLNS selected from the group consisting of said LFLNSs on said switching device, identifying as a loaded LFLNS each said first LFLNS wherein the number of said device addresses currently operatively associated with said first LFLNS in a forwarding table of said switching device is equal to or greater then said predetermined maximum number of said device addresses expected to be concurrently operatively associated with said first LFLNS, said operative association of a first device address and said first LFLNS in said forwarding table indicating a reasonable expectation by said switching device that the device associated with said first device address is operatively coupled with said first LFLNS;
(iii) executing a forwarding decision operation on said switching device for a unicast frame to be forwarded by said switching device, said forwarding decision operation comprising (a) looking up the destination LNS said device address operatively associated with said unicast frame in said forwarding table of said switching device and (b) excluding each second LFLNS from selection as an LNS for the forwarding of said frame if (1) said destination device address was not operatively associated with said second LFLNS in said forwarding table and (2) said second LFLNS is currently identified as a loaded LFLNS.
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Accused Products
Abstract
An improved method and apparatus for making forwarding decisions in a switching device. The invention reduces the flooding of frames to particular network segments connected to the switch. To insure a device sees a frame addressed to it, if a switch does not know what segment a device address is connected to for a unicast frame, the switch typically floods the frame to all segments in the broadcast domain. This invention allows segments to be identified as having a predefined maximum number of device addresses that will be associated with it. When that number of addresses is already in the forwarding table the switch will not flood unicast frames to that segment since no more devices should be connected to that segment.
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Citations
20 Claims
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1. A method for limiting the flooding of unicast traffic on one or more logical network segment (LNS) operatively coupled with a switching device said switching device comprising one or more ports each said port capable of operatively coupling one or more of said LNSs and said switching device, said switching device capable of bridging and filtering data frames between said operatively coupled LNSS, said method comprising:
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(i) identifying and selecting one or more limited flooding logical network segment (LFLNS) selected from the group consisting of said LNSs operatively coupled to said switching device wherein (a) a selected LFLNS has a predetermined maximum number of device addresses expected to be concurrently operatively associated with said LFLNS and (b) said method is to be utilized on said LFLNS; (ii) for one or more first LFLNS selected from the group consisting of said LFLNSs on said switching device, identifying as a loaded LFLNS each said first LFLNS wherein the number of said device addresses currently operatively associated with said first LFLNS in a forwarding table of said switching device is equal to or greater then said predetermined maximum number of said device addresses expected to be concurrently operatively associated with said first LFLNS, said operative association of a first device address and said first LFLNS in said forwarding table indicating a reasonable expectation by said switching device that the device associated with said first device address is operatively coupled with said first LFLNS; (iii) executing a forwarding decision operation on said switching device for a unicast frame to be forwarded by said switching device, said forwarding decision operation comprising (a) looking up the destination LNS said device address operatively associated with said unicast frame in said forwarding table of said switching device and (b) excluding each second LFLNS from selection as an LNS for the forwarding of said frame if (1) said destination device address was not operatively associated with said second LFLNS in said forwarding table and (2) said second LFLNS is currently identified as a loaded LFLNS. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An apparatus with limited flooding of unicast traffic on one or more logical network segment (LNS) said apparatus comprising:
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(i) one or more ports each said port capable of communicatively coupling with one or more logical network segment (LNS); (ii) one or more forwarding table said forwarding table capable of associating one or more device addresses with a said port; (iii) one or more processor capable of executing a forwarding decision operation; wherein said ports comprise a means of sending and receiving frames over said one or more LNS; and wherein when a frame is received on a said LNS, said forwarding decision operation selects a group of zero or more LNSs on which to forward said frame; and wherein one or LNSs are identified as limited flooding LNSs (LFLNSs), said LFLNSs having a predetermined maximum number of device addresses expected to be concurrently operatively associated with said LFLNS; and wherein when a said LFLNS is associated with at least said maximum number of said device addresses in said forwarding table, said LFLNS is identified as a loaded LFLNS; and wherein when said forwarding decision operation does not find the destination device address in said forwarding table for a unicast destination addresss and said forwarding decision operation selects to flood said frame to a group of ports, said LFLNS are excluded from said group of LNSs for flooding. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification