US 9021112

Patent Overview — US9021112B2

Title: Content request routing and load balancing for content distribution networks

Patent number / application: US9021112B2; Application US12/050,648.

Inventors: Michael Slocombe, Matthew Miller, Casey Ajalat, Vincent A. Fuller, III.

Assignee information (as listed): Original assignee Level 3 Communications LLC; current assignees listed as Genuity Inc and Sandpiper CDN LLC. (Recorded reassignments appear in the source; they are noted here only as listed.)

Key dates (as listed): Prior art date 2001-10-18; filing date 2008-03-18; publication of US20080235400A1 on 2008-09-25; grant/publication of US9021112B2 on 2015-04-28; anticipated expiration 2021-10-18. Legal status: Expired – Fee Related.

Purpose: Embodiments relate generally to information retrieval in a network and, more particularly, to hosting and distributing content on a content delivery network such as the Internet. The stated aim is to let a content requester retrieve content from a content site closer than the content provider's origin server, while distributing load from many end users among multiple systems across different parts of the network.

Plain-language scope (from the excerpt): A method of content delivery in a network includes associating Domain Name System (DNS) devices with content server systems that maintain and serve a content provider's content, each DNS device configured to resolve the provider's name to an address for its associated content server system. The method further includes assigning to the DNS devices a common address, usable to resolve the provider's name so that a content request is sent to the content server system nearest the requestor. The described implementation uses pre-existing routing infrastructure, anycast address service, and Border Gateway Protocol (BGP); because DNS uses a stateless protocol (UDP) for routing, the approach is described as handling anycast-addressable caching without problems associated with anycast service, such as potential packet-by-packet load-balancing side effects of stateful protocols like TCP.

Source: https://patents.google.com/patent/[US9021112](/patent/US9021112)/en

What the excerpt does not establish: It does not provide the full claims, detailed description, or drawings; the complete written description; the full prosecution history; the precise current ownership chain; or any determination of validity, enforceability, or claim scope. The supplied text is an excerpt (indicated by "consult the source for omitted text"), and the provided figures (FIG. 1–5) are referenced but not reproduced here.