- From: Bence Béky <bnc@chromium.org>
- Date: Fri, 8 May 2015 09:37:15 -0400
- To: HTTP <ietf-http-wg@w3.org>
Hello httpbis, This is a heads up about a parameter that we have been using in Alternate-Protocol headers, and are planning to use in Alt-Svc headers and ALTSVC frames. It is "p=" (probability), that Google servers emit and Chrome observes. This takes a numerical value between 0.0 and 1.0 inclusive, and tells the client to only observe the alternative service with that given probability (and ignore it otherwise). This parameter can be used for finer grade load balancing, for gradual rollout of a new protocol, and for performance testing. My understanding is that the current HTTP Alternative Services draft at https://tools.ietf.org/id/draft-ietf-httpbis-alt-svc-06.html#rfc.section.3 permits parameters other than "ma=", therefore using a customary parameter is conformant to the specification. If there is interest in more technical documentation of this parameter, I would be happy to coordinate efforts of writing that documentation on our part. Given that according to my best understanding, the Alternative Services specification is not in Last Call yet, there is the possibility of including the probability parameter in that document in case there is a benefit to the community. In case of lack of interest, this was just an FYI. Thank you, Bence
Received on Friday, 8 May 2015 13:38:08 UTC