Partition network state by the network partition key (which consists of top frame site and possibly frame site), to protect against cross-site tracking through the use of side channels. "Network State" here includes connections (H1, H2, H3, websocket), the DNS cache, ALPN/H2 support data, TLS/H3 resumption information, Reporting/NEL configuration and uploads, and Expect-CT information. Explainer:


Cross-site tracking is a major privacy concern for users. This is a necessary part of addressing the problem.


Specification link

Final published standard: Recommendation, Living Standard, Candidate Recommendation, or similar final form

Status in Chromium


In developer trial (Behind a flag) (tracking bug)

Consensus & Standardization

After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.


Intent to Prototype url

Intent to Prototype thread


Note that the tracking bug covers more than this feature covers.

Last updated on 2021-12-05