PTAB challenges

Proceedings overview

There is one AIA trial proceeding on file for US patent 10701173: IPR2026-00180. This proceeding is currently Pending, with no final decision on the patentability of claims. This early stage means the patent's claims remain untested by the PTAB for now.

IPR2026-00180 — Microsoft Corporation v. Sandpiper CDN LLC

• Type: Inter Partes Review
• Filed: 2025-12-24
• Status: Pending. This IPR is in the initial stages, awaiting an institution decision from the USPTO Director.
• Judge panel: The judge panel for the trial phase would only be assigned if the IPR is instituted. Institution decisions are now made solely by the USPTO Director.
• Petition grounds: Microsoft Corporation, the petitioner, challenged all 14 claims of US10701173B2 (claims 1-14) on grounds of obviousness under 35 U.S.C. § 103.
  • Ground 1: Claims 1 and 8 are obvious over O'Rourke (U.S. Pat. No. 7,912,921). Petitioner argued that O'Rourke teaches a cache server in a CDN that uses flexible, user-determined cache policies, including a process of checking if content is local and then using policies to determine if the cached version is acceptable. The ability to add/remove "policy plug-ins" was asserted to teach the "late-binding" concept of determining a "current cache policy" upon request.
  • Ground 1A: Claims 2 and 9 are obvious over O'Rourke and Blumofe.
  • Ground 1B: Claims 4-6 and 11-13 are obvious over O'Rourke and MS-MSSO (Media Streaming Server System Overview, Microsoft Corporation, 2009).
  • Ground 1C: Claims 7 and 14 are obvious over O'Rourke and Blumofe. This ground targeted claims 7 and 14, which require the cache policy to relate to caching content both within the CDN and outside the CDN. Blumofe was cited for teaching a "CDN Extender" operating outside the CDN but controlled by the main CDN.
  • Ground 2: Claims 3 and 10 are obvious over O'Rourke and MS-MSSO. This ground addressed claims 3 and 10, which specify that the content request is an HTTP request and the content comprises one or more resources.
  • Ground 2A: Claims 1-2, 4-6, 8-9, and 11-13 are obvious over Middleton (U.S. Pat. No. 6,185,598) alone. Middleton was cited for teaching an extensible CDN platform where an edge server uses cache policies like Time-To-Live (TTL) values.
  • Ground 2B: Claims 3 and 10 are obvious over Middleton and MS-MSSO.
  • Ground 2C: Claims 7 and 14 are obvious over Middleton and Blumofe.
  • Prior Art Relied Upon: O'Rourke (U.S. Pat. No. 7,912,921), MS-MSSO (Media Streaming Server System Overview, Microsoft Corporation, 2009), Middleton (U.S. Pat. No. 6,185,598), and Blumofe (U.S. Published Patent Application No. 2004/0073663).
• Institution decision: Not yet issued. The institution decision is due approximately 6 months from the filing date (December 24, 2025), which would be around June 24, 2026. As of October 20, 2025, the USPTO Director is solely responsible for deciding whether to institute IPR trials. Recent policy changes also require the Director to consider factors such as U.S. manufacturing activity when making institution decisions.
• Final Written Decision (if issued): Not applicable, as the IPR is still pending an institution decision.
• Settlement / termination: Not applicable, as the IPR is still pending an institution decision.
• Appeal: Not applicable.
• Defensive value: This proceeding indicates that Microsoft Corporation believes all 14 claims of US10701173B2 are vulnerable to obviousness challenges based on the cited prior art. If the IPR is instituted and claims are invalidated, it would significantly weaken the patent. However, as it is still pending institution, the claims currently remain intact.

Strategic summary

US patent 10701173 currently has all 14 of its claims (claims 1-14) untested by any PTAB Final Written Decision. The sole IPR proceeding, IPR2026-00180, filed by Microsoft Corporation, challenges all of these claims based on various obviousness grounds, primarily citing O'Rourke, MS-MSSO, Middleton, and Blumofe. This IPR is still in its early stages, awaiting a decision on whether to institute a trial.

The estoppel landscape has not yet been formed by this proceeding. If IPR2026-00180 is instituted and proceeds to a Final Written Decision, 35 U.S.C. § 315(e)(2) would bar Microsoft (and its privies) from asserting in future district court litigation or other USPTO proceedings any ground of invalidity that it raised or reasonably could have raised during the IPR. Until then, all prior-art grounds remain available to other potential challengers. Given the recent policy shifts at the USPTO, where the Director now solely decides on institution and may consider factors like U.S. manufacturing footprint, the outcome of the institution decision for IPR2026-00180 is subject to these new discretionary considerations.

There isn't a clear pattern signal yet from this single, pending IPR. However, the petitioner being Microsoft Corporation suggests a significant defendant is actively challenging the patent. There is also a related district court case, Sandpiper CDN, LLC v. Microsoft Corporation (2:25-cv-00664) in the Eastern District of Texas, filed on 2025-06-26, alleging infringement of this and other patents. This IPR is likely a defensive maneuver in response to that litigation.

Recommended next steps

• Monitor the status of IPR2026-00180 closely. The institution decision is expected around June 24, 2026. A favorable decision for Microsoft would indicate that the PTAB Director believes there is a reasonable likelihood that at least one of the challenged claims is unpatentable, opening the door for trial. A denial of institution would strengthen the patent owner's position against future IPR challenges by Microsoft on these grounds.
• Review the IPR petition and any Patent Owner Preliminary Response (if filed) for IPR2026-00180 on the USPTO PTAB E2E portal (searchable via https://www.uspto.gov/patents/ptab) to understand Microsoft's full invalidity arguments and Sandpiper CDN LLC's responses.
• Given the concurrent district court litigation (2:25-cv-00664 in E.D. Texas), understanding the interplay between the IPR and the court proceedings is crucial, especially regarding potential stays of litigation if the IPR is instituted.## Proceedings overview

There is one AIA trial proceeding on file for US patent 107011173: IPR2026-00180. This proceeding is currently Pending, with no final decision on the patentability of claims, meaning the patent's claims remain untested by the PTAB for now.

IPR2026-00180 — Microsoft Corporation v. Sandpiper CDN LLC

• Type: Inter Partes Review
• Filed: 2025-12-24
• Status: Pending. This IPR is in the initial stages, awaiting an institution decision from the USPTO Director.
• Judge panel: The judge panel for the trial phase would only be assigned if the IPR is instituted. Institution decisions are now made solely by the USPTO Director.
• Petition grounds: Microsoft Corporation, the petitioner, challenged all 14 claims of US10701173B2 (claims 1-14) on grounds of obviousness under 35 U.S.C. § 103.
  • Ground 1: Claims 1 and 8 are obvious over O'Rourke (U.S. Pat. No. 7,912,921). Petitioner argued that O'Rourke teaches a cache server in a CDN that uses flexible, user-determined cache policies, including a process of checking if content is local and then using policies to determine if the cached version is acceptable. The ability to add/remove "policy plug-ins" was asserted to teach the "late-binding" concept of determining a "current cache policy" upon request.
  • Ground 1A: Claims 2 and 9 are obvious over O'Rourke and Blumofe (U.S. Published Patent Application No. 2004/0073663).
  • Ground 1B: Claims 4-6 and 11-13 are obvious over O'Rourke and MS-MSSO (Media Streaming Server System Overview, Microsoft Corporation, 2009).
  • Ground 1C: Claims 7 and 14 are obvious over O'Rourke and Blumofe. This ground targeted claims 7 and 14, which require the cache policy to relate to caching content both within the CDN and outside the CDN. Blumofe was cited for teaching a "CDN Extender" operating outside the CDN but controlled by the main CDN.
  • Ground 2: Claims 3 and 10 are obvious over O'Rourke and MS-MSSO. This ground addressed claims 3 and 10, which specify that the content request is an HTTP request and the content comprises one or more resources.
  • Ground 2A: Claims 1-2, 4-6, 8-9, and 11-13 are obvious over Middleton (U.S. Pat. No. 6,185,598) alone. Middleton was cited for teaching an extensible CDN platform where an edge server uses cache policies like Time-To-Live (TTL) values.
  • Ground 2B: Claims 3 and 10 are obvious over Middleton and MS-MSSO.
  • Ground 2C: Claims 7 and 14 are obvious over Middleton and Blumofe.
  • Prior Art Relied Upon: O'Rourke (U.S. Pat. No. 7,912,921), MS-MSSO (Media Streaming Server System Overview, Microsoft Corporation, 2009), Middleton (U.S. Pat. No. 6,185,598), and Blumofe (U.S. Published Patent Application No. 2004/0073663).
• Institution decision: Not yet issued. The institution decision is due approximately 6 months from the filing date (December 24, 2025), which would be around June 24, 2026. As of October 20, 2025, the USPTO Director is solely responsible for deciding whether to institute IPR trials. Recent policy changes also require the Director to consider factors such as U.S. manufacturing activity when making institution decisions.
• Final Written Decision (if issued): Not applicable, as the IPR is still pending an institution decision.
• Settlement / termination: Not applicable, as the IPR is still pending an institution decision.
• Appeal: Not applicable.
• Defensive value: This proceeding indicates that Microsoft Corporation believes all 14 claims of US10701173B2 are vulnerable to obviousness challenges based on the cited prior art. If the IPR is instituted and claims are invalidated, it would significantly weaken the patent. However, as it is still pending institution, the claims currently remain intact.

Strategic summary

US patent 10701173 currently has all 14 of its claims (claims 1-14) untested by any PTAB Final Written Decision. The sole IPR proceeding, IPR2026-00180, filed by Microsoft Corporation, challenges all of these claims based on various obviousness grounds, primarily citing O'Rourke, MS-MSSO, Middleton, and Blumofe. This IPR is still in its early stages, awaiting a decision on whether to institute a trial.

The estoppel landscape has not yet been formed by this proceeding. If IPR2026-00180 is instituted and proceeds to a Final Written Decision, 35 U.S.C. § 315(e)(2) would bar Microsoft (and its privies) from asserting in future district court litigation or other USPTO proceedings any ground of invalidity that it raised or reasonably could have raised during the IPR. Until then, all prior-art grounds remain available to other potential challengers. Given the recent policy shifts at the USPTO, where the Director now solely decides on institution and may consider factors like U.S. manufacturing footprint, the outcome of the institution decision for IPR2026-00180 is subject to these new discretionary considerations.

There isn't a clear pattern signal yet from this single, pending IPR. However, the petitioner being Microsoft Corporation suggests a significant defendant is actively challenging the patent. There is also a related district court case, Sandpiper CDN, LLC v. Microsoft Corporation (2:25-cv-00664) in the Eastern District of Texas, filed on 2025-06-26, alleging infringement of this and other patents. This IPR is likely a defensive maneuver in response to that litigation.

Recommended next steps

• Monitor the status of IPR2026-00180 closely. The institution decision is expected around June 24, 2026. A favorable decision for Microsoft would indicate that the PTAB Director believes there is a reasonable likelihood that at least one of the challenged claims is unpatentable, opening the door for trial. A denial of institution would strengthen the patent owner's position against future IPR challenges by Microsoft on these grounds.
• Review the IPR petition and any Patent Owner Preliminary Response (if filed) for IPR2026-00180 on the USPTO PTAB E2E portal (searchable via https://www.uspto.gov/patents/ptab) to understand Microsoft's full invalidity arguments and Sandpiper CDN LLC's responses.
• Given the concurrent district court litigation (2:25-cv-00664 in E.D. Texas), understanding the interplay between the IPR and the court proceedings is crucial, especially regarding potential stays of litigation if the IPR is instituted.