US 8495725

US8495725 — Patent Overview

Title: Methods, systems, and computer readable media for adaptive packet filtering
Patent number: US8495725B2
Inventor: David K. Ahn
Assignee of record (per source): Great Wall Systems; later Centripetal Networks LLC (as listed)
Priority date: 2009-08-28 | Filed: 2010-08-30 | Granted/Published: 2013-07-23
Application number: US12/871,806 | Status: Active; anticipated expiration 2030-08-30

Purpose. The patent addresses firewall scalability. Per the source, firewalls generally process packets against an ordered rule list to find the first match, and the list represents an aggregate security policy whose order cannot be arbitrarily changed. Prior WFU reordering/parallelization techniques can still degrade as the rule count grows, because linear search may require up to N comparisons per packet. The described "adaptive packet filtering" (APF) is a set of techniques for processing firewall rules and packets, intended to improve performance, and can be combined with WFU or other parallel/pipelining/optimization techniques.

Plain-language scope. One described method identifies at least one subset of rules in an ordered firewall rule set such that the subset contains disjoint rules — rules whose order can be changed without changing the integrity of the policy. Rules in the subset are sorted to statistically reduce packet comparisons. Packets are then filtered using the sorted subset via binary search, interpolated search, informed search, or hash lookup, until the packet is allowed or denied, with comparison ceasing at that point, thereby achieving sub-linear searching. The subject matter can be embodied as a non-transitory computer readable medium (including chip memory, disk memory, programmable logic devices, ASICs), distributed across devices, or as a network firewall with interfaces and packet-filtering hardware/software.

Source: https://patents.google.com/patent/US8495725/en

What the excerpt does not establish. It does not provide the full claim text, complete specification, drawings, or the scope of any specific claim. It also does not establish validity, infringement, enforceability, the accuracy of the listed assignee/status, or the content of cited prior art. The excerpt indicates omitted text ("Excerpt only"), so no legal conclusions should be drawn from it.