Re: First draft of negotiation requirements document

Ted Hardie (hardie@thornhill.arc.nasa.gov)
Tue, 17 Jun 1997 14:39:09 -0700 

On Jun 17, 11:04pm, Koen Holtman wrote:
> Section 3 start of last paragraph:
>
> |Content negotiation based on User-agent strings also creates
> |difficulties for caching proxies,
> The same problems also exist for negotiation based on Accept headers.

I see no problem in changing it to:

"Content negotiation based on Accept headers or User-agent strings....",
if you think that meets the case.

> Section 5.2.1 end of first paragraph:
>
> | [TCN] describes a standard method for delineating
> |the axes along which a resource varies and a set of methods by which
> |caches can participate in the negotiation process.
>
> I assume that you mean that remote variant selection algorithms are in
> this set of methods.  In that case, it would be better to write
>
>  `a set of methods by which origin servers and proxy caches can
>  optimize the negotiation process.'

I think we still need to test whether or not they do optimize the
negotiation process.  I think it is very clear that they allow the proxy
caches to participate in the negotiation, but that we will need actual
data on hit rates using proxy-negotiated selections before we can
say that it works.  I agree that the current language is a bit weak, but
I think it would be more useful to find language which concisely describes
*how* they participate.  Any help you can provide there would be
much appreciated.

> Section 5.2.1 last sentence:
>
> |Many times, however, this process [elective negotiation] requires a
> |user to actively select among the resources provided, which reduces
> |perceived efficiency and increases perceived latency.
>
> I am not sure what you mean by `many times'.  Do you mean `for many
> methods of elective negotiation'?  You would always select by hand
> with the `click here for...' negotiation method you describe first.
> But for TCN, selection is automatic.  A list of variants for the user
> to select would only appear if the user asks for it, or in an error
> message if the user agent detects that every variant is completely
> unacceptable according to its configuration database.

I meant that the current user experience of elective negotiation commonly
involves a manual selection.  If it were replaced with:

"this proccess may require a user to select among a list of resources, which
reduces perceived efficiency and increases perceived latency."

would that work better?

Thanks for your comments,
			regards,
				Ted Hardie
				NASA NIC


> Koen.
>-- End of excerpt from Koen Holtman