[TLS] The qpack_static_table_version TLS extension (Draft version 02)

[Rory Hewitt <[e-mail]>]

Hey folks,

Following my presentation at the meeting at IETF 118 today (thanks for
taking it easy on me, as this was my first IETF appearance as well as being
my first I-D), I have created another version of my I-D:

https://www.ietf.org/archive/id/draft-hewitt-ietf-qpack-static-table-version-02.html

Significant changes from version-01 are as follows:

1. I changed references to registry "Version" to "Variant" to make it clear
that they could be very different.

2. I added a section on vendor-defined registries, which would contain
static tables that might be much smaller and/or contain vendor-specific
field names or values - for instance for personal assistants and APIs which
only use a very small set of headers with known values.

3. In the QPACK Static Table Background
<https://www.ietf.org/archive/id/draft-hewitt-ietf-qpack-static-table-version-02.html#name-qpack-static-table-backgrou>
section,
I added an example showing how the use of a static table can significantly
reduce bytes on the wire by passing only 2- or 3-byte references to much
longer strings that are known to both client and server.

4. The details of the TLS extension has been changed so that it is no
longer simply a Variant/Length pair, but similarly to ciphersuite support,
it is (when passed in the ClientHello) an array of Variant/Length
combinations supported by the client and (when passed in the ServerHello) a
single negotiated Variant/Length pair which will be used by both client and
server.

Note that the draft still refers to this as a "TLS extension" - I think
many of us agree that it would be preferable if it were defined in ALPS,
but since ALPS support is still minimal, I'll keep referring to it as a TLS
extension for now. Given that, I would really appreciate any comments on
the high-level concept, on the understanding that it may not end up being a
TLS extension. Speaking of which, where can I find details of why ALPS was
not taken up - it was mentioned in the meeting that there were 'concerns'
about ALPS, but I'm not clear on what they were or who was concerned - HTTP
WG or TLS WG or both or some other entity?

Finally, I'm still trying to build a test harness to determine whether the
benefits of any additional compression make sense - is this even worth the
hassle? I would greatly appreciate any help on this - you'll get co-author
credit, for what that's worth :)

Thanks,

Rory