US 10701173

US patent 10701173, titled "Caching in a content delivery framework," was issued on June 30, 2020. The application for this patent, US15/588,935, was filed on May 8, 2017. The inventors are Christopher Newton and William Crowder. While Level 3 Communications LLC was the original assignee, the current assignee is Sandpiper Cdn LLC as of a 2024-07-09 assignment.

Abstract:
The patent describes a computer-implemented method for caching within a content delivery network (CDN) that utilizes "late binding" of caching policies. When a caching node in the CDN receives a request for content, it first determines if that content is already cached locally. If it is, the node then determines the current cache policy associated with the content. Based on this policy, the node decides whether the locally cached version is acceptable to serve. If it's not acceptable, a new version of the content is obtained and served. Otherwise, if the locally cached version is acceptable, it is served. [cite: US10701173B2]

Plain-language overview of Independent Claims:

• Independent Claim 1 (Computer-Implemented Method):
  This claim describes a method for a node within a Content Delivery Network (CDN) to handle content requests.

  1. When a request for content is received, the node checks if it has a local copy of that content.
  2. If the content is cached locally, the node then determines the most up-to-date caching policy for that content, specifically identifying how long the content should be considered valid in the cache.
  3. Using this current cache policy, the node decides if it's okay to deliver the locally cached content.
  4. If the locally cached content is not acceptable based on the current policy (e.g., it's stale), the node gets and serves a new version of the content.
  5. If the locally cached content is acceptable, the node serves that local version. [cite: US10701173B2]

• Independent Claim 8 (Computer Program Product):
  This claim covers a computer program product, essentially software instructions stored on a non-transitory computer-readable medium. These instructions, when run on a device with hardware (like memory and a processor) within a CDN, implement the exact same method described in Claim 1. That is:

  1. In response to a content request, a CDN node determines if the content is locally cached.
  2. If locally cached, the node determines the current cache policy, including the content's expiration time.
  3. Based on this policy, the node decides if the locally cached content can be served.
  4. If not acceptable, a new version is obtained and served.
  5. If acceptable, the locally cached version is served. [cite: US10701173B2]

Litigation Status:
The patent family is involved in litigation. A PTAB case, IPR2026-00180, has been filed and is currently pending. Additionally, a US case has been filed in the Texas Eastern District Court (case 2:25-cv-00664). [cite: US10701173B2]