US 7724662

Patent Overview: US7724662B2 — "Dynamic rate limiting adjustment"

Bibliographic data (from supplied text)

• Patent number: US7724662B2; application US11/998,654, filed 2007-11-30; granted 2010-05-25.
• Priority date listed as 2002-07-17; legal status shown as "Expired - Fee Related," with adjusted expiration 2023-04-12.
• Inventor: Fan Xu. Original assignee: Foundry Networks LLC. Current assignees listed: Avago Technologies International Sales Pte Ltd and Foundry Networks LLC.
• Classification: H04L47/00, H04L47/10 (traffic control/flow control, congestion control), H04L47/39 (credit based).
• Source: https://patents.google.com/patent/[US7724662](/patent/US7724662)/en

Purpose
The patent addresses shortcomings in credit-based rate limiting. Because a credit cannot be partially consumed and traffic arrives unevenly, actual throughput can drift from the configured limit; dropped packets may also cause TCP applications to slow down, further widening the gap. The disclosed approach samples actual output rates from a rate-limited device and uses that information to modify configured traffic limits, so actual output rates converge toward the desired limits.

Plain-language scope
A two-part system—a hardware component and a software component—limits traffic rates for defined traffic classes on a switch or router. The hardware may support up to 128 traffic classes per chip; a class may correspond to a physical port, an outgoing queue, or a flow defined by an ACL group. Credits, each worth a fixed number of bytes, are issued per time interval; packets are forwarded if the class counter has enough credits and dropped otherwise. Operation is either "accumulated mode" (unused credits carry over) or "fixed mode" (unused credits are lost). Software sets intervals and credit values, computing credits from a configured rate R_c; a dynamic rate adjustor samples the actual average output rate R_s every Δt seconds, compares it to R_c, and sends the sum of C and Δc as the new credit allotment until convergence.

What the excerpt does not establish
The supplied text omits the claims, detailed description, and drawing content; it does not establish specific claim language, the full adjustor algorithm, other cited prior art, or litigation, ownership, or validity matters—which are outside this scope.