Subject: Re: Capability terminology

From: Graham Klyne <[email-masked]>
Date: Thu, 12 Nov 1998 12:43:59 +0000

At 11:19 11/11/98 -0800, Dan Wing wrote:
>On Wed, 11 Nov 1998, Graham Klyne wrote:
>
>>   "capability exchange" describes any transfer of 
>>   information between communicating systems that is used to 
>>   indicate system capabilities and hence determine the form 
>>   of data transferred.
>
>"Exchange" is a two-way transaction.  I "exchange" US dollars for
>a foreign currency (two-way transaction).  I "exchange" my efforts
>at work for my paycheck.  My body "exchanges" oxygen for carbon
>dioxide.

True.  I used this form of definition because the term "capability
exchange" has also been used in the fax context which is not a two-way
communication.

But I could accept a definition that goes either way.

#g

------------
Graham Klyne
([email-masked])

---

From: Dan Wing <[email-masked]>
Date: Thu, 12 Nov 1998 14:05:44 -0800 (PST)

> exchange" has also been used in the fax context which is not a two-way

With fax there isn't a symmetric capabilities exchange but there is a
capabilities exchange between the transmitting and receiving terminals.

However, the existing proposals for capabilities aquisition for email
such as LDAP, DSN/MDN messages, etc., do not cause the sender to
provide any of its capability information at all.

Perhaps this is something we should address:  a sender knows what file
types it could render a source document in: image/tiff, image/jpeg,
application/pdf, etc., and maybe it would be useful for the sender to
query the recipient with details on the recipient's ability to handle each
individual MIME type.  I am sure in practice that this would degrade to
http's "Accept: */*" pretty quickly, though....

> But I could accept a definition that goes either way.

-Dan Wing