Re: [hybi] WebSocket and metadata (Was: BWTP Proposal - Bidirection Web Transfer Protocol)

[Salvatore Loreto <salvatore.loreto at ericsson.com>]

Ian Hickson wrote:
> On Tue, 16 Jun 2009, Salvatore Loreto wrote:
>   
> > It would be interesting understand why WebSocket does not have defined 
> > 'meta'; if there is any specific reason why there aren't.
> >     
>
> The WebSocket protocol is designed on the principle that there should be 
> minimal framing (the only framing that exists is to make the protocol 
> frame-based instead of stream-based, and to support a distinction between 
> Unicode text and binary frames). It is expected that metadata would be 
> layered on top of WebSocket by the application layer, in the same way that 
> metadata is layered on top of TCP/IP by the application layer (HTTP).
>   
I don't see any minimal framing requirement from the requirements list 
you sent on this list a couple
of months ago:
http://www.ietf.org/mail-archive/web/hybi/current/msg00007.html

actually, in theory also BWTP meets all the requirements you have listed 
in that mail.
> Conceptually, WebSocket is really just a layer on top of TCP/IP that adds 
> a Web "origin"-based security model for browsers; 
the problem here is that WebSocket are not built directly on top of TCP/IP,
but it tries to reuse the HTTP infrastructure to in somehow perform a 
downgrade from the HTTP protocol to
the TCP protocol and then start to build on top of it.
So IMHO the protocol should try to interwork in a fair way with the 
existent HTTP infrastructure,
asking for as minimal as possible update to the elements present in that 
infrastructure.

regards
Sal

> adds an addressing and 
> protocol naming mechanism to support multiple services on one port and 
> multiple host names on one IP address; and layers a framing mechanism on 
> top of TCP to get back to the IP packet mechanism that TCP is built on, 
> but without length limits. Other than that, it adds nothing. 
> Basically it 
> is intended to be as close as possible to just exposing raw TCP/IP to 
> script as possible given the constraints of the Web. (It's also designed 
> in such a way that its servers can share a port with HTTP servers, by 
> having its handshake be a valid HTTP Upgrade handshake also.)
>
> HTH,
>