RE: CCPP Implementation

Hi Peter,

Some more comments on HTTP-ex. I want to say in advance 
that I'm not trying to be argumentative about this - it's just 
that as the CCPPex document is only a W3C note so it is only a 
suggestion and hasn't been through a formal W3C process. 
If it had been through a formal W3C process then I would have 
had an opportunity to raise my concerns about it. I feel these 
concerns are important which is why I want to explain them here. 
As ever comments / criticisms / suggestions on these concerns
are welcome. 

Firstly I think ideally all devices should use the same protocol 
regardless whether they are WAP or PCs. This is desirable from 
a device independence point of view - see 
http://www.w3.org/TR/2001/WD-di-princ-20010918/.  

Unfortunately the CCPPex document is only a W3C note so it not
a recommendation for a protocol (as a colleague has pointed 
out to me, the W3C produces recommendations not standards). 
The WAP folks have two protocols: one based on 
the CCPPex note, the other based on HTTP/1.1 (W-HTTP). 
All WAP devices have to support W-HTTP, but gateways and 
clients may optionally support the one based on CCPP-ex also.

Therefore one way of settling on a single protocol would be for
everyone to adopt W-HTTP. This protocol has the same functionality
as the CCPP-ex protocol. 

Also I'd just like to clarify the problems with CCPPex:

1. HTTP-ex is an experimental protocol and W3C recommendations
shouldn't be based on experimental protocols. Look at the RFC 
ftp://ftp.isi.edu/in-notes/rfc2774.txt which clearly states 
"This memo defines an Experimental Protocol for the Internet 
community. It does not specify an Internet standard of any kind."

2. If you use HTTP-ex you need provide support numerical 
namespaces. For people using standard frameworks like J2EE or 
servlets, this will require extra work compared to W-HTTP
(I don't think Jigsaw counts as a standard framework - not
yet anyway).

3. If clients use the new HTTP-ex methods, they won't work with 
existing servers although as you note this is for mandatory 
extensions. 
   
4. There doesn't seem to be much interest in HTTP-ex anymore
- see the mailing list archive at http://lists.w3.org - so is
it likely to move from an experimental status to an approved 
status?

Johan Hjelm, chairman of the CC-PP working group has commented
previously:

"We are trying to wrap up the (CC/PP) spec to go to candidate 
recommendation now, and then we will recharter the group to 
restart the work (I know, I have been saying that for a while 
now). One reason is for that is to do the protocol work properly
- the numerical namespaces in the HTTP header comes from the 
HTTP Extension Framework, and that was actually more or less a 
political decsion. It would have been much cleaner to do a new 
HTTP header, but we were not allowed to do so at the time."

regards

Mark H. Butler, PhD
Research Scientist
HP Labs Bristol

Received on Wednesday, 5 December 2001 09:22:08 UTC