The IESG has approved the following document: - 'CDN Loop Detection' (draft-ietf-httpbis-cdn-loop-02.txt) as Proposed Standard This document is the product of the Hypertext Transfer Protocol Working Group. The IESG contact persons are Adam Roach, Alexey Melnikov and Ben Campbell. A URL of this Internet Draft is: https://datatracker.ietf.org/doc/draft-ietf-httpbis-cdn-loop/ Technical Summary This simple document defines a new request header field for HTTP: CDN-Loop. CDN-Loop addresses an operational need that occurs when an HTTP request is intentionally forwarded between CDNs but then is accidentally re-routed back into the original CDN causing a non terminating loop. The new header field is used to identify the error and terminate the loop. The document was co-authored by employees of three different large CDNs. Working Group Summary The group was largely in agreement that this was a sensible solution and consensus was quickly reached. About 35 emails were exchanged on the document. A majority of the comments dealt with the relationship between CDN-Loop and the existing Via header field. Consensus was reached that Via was essentially 'burned' at this point and not operationally suitable for that purpose. Document Quality Participation in the document's review and development was sufficient given the tight scope of the document. In addition to the 3 primary authors, 9 other individuals weighed in with comments and reviews. This represented contributors from both clients, servers, and intermediaries The Working Group Last Call requested information on any plans to implement. In addition to the author's CDNs one other CDN stepped forward at that time with interest. There has been at least one pre-release deployment already. Personnel Tommy Pauly is the document shepherd; Alexey Melnikov is the responsible Area Director.