Re: [hybi] Compression spec decoupling

["Arman Djusupov" <[e-mail]>]

I'm also fine with both options.

 

With best regards,

Arman

 

From: Takeshi Yoshino [mailto:[e-mail]] 
Sent: Thursday, April 26, 2012 7:24 AM
To: [e-mail]; John Tamplin; Arman Djusupov; Greg Wilkins
Subject: Compression spec decoupling

 

As the target data is close, I'd like to list options with concrete examples
and call for opinions to settle this topic.

 

See also this thread:
http://www.ietf.org/mail-archive/web/hybi/current/msg09469.html

 

We have two options.

(I saw slight objection to add a new handshake header to pass algorithm
parameter in f2f meeting)

 

a) One per-frame compression extension for all compression algorithm

 

draft-ietf-hybi-websocket-perframe-compression defines

- an extension "perframe-compress" and how it frames data including usage of
RSV1

- an extension parameter "algorithm" and its format

- an algorithm parameter "deflate" and how it transforms data

 

RSV1 is given to perframe-compress extension. It might make incompatible
extension checking easier.

 

There something does "per-frame compression" but needs framing beyond what
we define in this spec might come in the future. Then, we need to choose
either of break this 1:1 assignment or forbid it to use RSV1.

 

Example:

Sec-WebSocket-Extensions: perframe-compress; algorithm="foo; foo-param1=123,
bar; bar-param1=abc"; general-param1=xyz", ...

 

Example (with mux):

Sec-WebSocket-Extensions: perframe-compress; algorithm="... (algorithms for
pre-mux) ...", mux, perframe-compress; algorithm="... (algorithms for
post-mux) ..."

 

b) One extension for each per-frame compression algorithm

 

draft-ietf-hybi-websocket-perframe-compression defines

- a method how to frame data with per-frame compression including usage of
RSV1

- an extension "deflate-frame" which uses the framing method and how to
transforms data

 

RSV1 is given to any extension that does per-frame compression. Endpoints
need to sort out mutually exclusive extensions.

 

Any future per-frame compression extension may or may not refer to the
framing method defined in draft-ietf-hybi-websocket-perframe-compression.

 

Example:

Sec-WebSocket-Extensions: foo-compress; foo-param1=123, bar-compress;
bar-param-1=abc, ...

 

Example (with mux):

Sec-WebSocket-Extensions: ... (extensions for pre-mux) ...", mux, ...
(extensions for post-mux) ..."