Alt-SvcB

[Martin Thomson <[e-mail]>]

Hey everyone,

The Alt-Svc design team has been very busy recently and making some progress on working out an alternative alternative services design.

I just posted https://martinthomson.github.io/alt-svcb/draft-thomson-httpbis-alt-svcb.html as a -00 draft.  This outlines the alternative design that we've been exploring in the design team.

The basic idea is split into two procedures:

1. Use: When an Alt-SvcB field or ALTSVCB frame is encountered, the client looks for HTTPS records for the provided name in the DNS and creates a connection using what it learns.
2. Reuse: When a client that has previously used an alternative service connects again, it remembers the HTTPS record that worked.  It performs a regular HTTPS record lookup for the server - not using the alternative that it learned, but the name from the URI - but it prefers the alternative it previously used if that alternative appears in the results.

The draft explains in more detail and goes into some of the implications of the design.

This is not done by any imagining.  We have a bunch of open issues at https://github.com/martinthomson/alt-svcb/issues that do require some amount of input.  But we think that this is a promising approach and would appreciate more input.

Cheers,
Martin