Re: draft-ietf-impp-pres-01

I mean case 2.
Comparing URIs is seldom as simple as comparing bit-streams.

As I think you are saying, if you scope the identifier to a context
then the cost of recognizing that identifier includes the cost of
recognizing the context. If the recognizing the context just involves
adding length to a bit-stream comparison, then we're splitting hairs
arguing complexity. However, if recognizing the context is more complex
(comparing URIs for example) we have something real to consider in the
tradeoff against the properties Thanos was asking for.

For those cases where identifying the context is simple, I would
prefer to avoid small increment in interop risk due to having to
look at multiple things in order to recognize the identifier.

For those cases where identifying the context is more complex, I
anticipate that the evaluation of effort to build a self-defining ID
vs effort to identify context will almost always fall out in favor
of building a self-defining ID. I'm sure counter-examples can be
constructed, but I don't know that we need to mine this problem
so deeply.

If I understood him, the specific context Thanos was proposing was
scoping the SubscriptID to To and From (I am supposing he means
watcher and target from impp-pres-01). Comparing these fields 
involves comparing pres: URIs. Comparing pres: URIs is much harder
than comparing bit streams.

Apologies if I misunderstood what Thanos was looking for.

RjS

On Wed, 2003-01-15 at 13:40, Dave Crocker wrote:
> Robert,
> 
> Wednesday, January 15, 2003, 11:18:54 AM, you wrote:
> Robert> Another point to consider is the complexity of comparisons withing
> Robert> the context. I would very much prefer to avoid having URI comparisons
> Robert> involved in comparisons of the subscription identifier.
> 
> 1.  If you mean longer string versus shorter string, surely the
> difference in length is not relevant either to system performance or
> code complexity.
> 
> 2.  If you mean something about "interpreting" the string carefully,
> then it is important to be careful about assessing complexity.  If the
> code must be careful to make sure that it is interpreting the "simpler"
> string in the correct context, then the code will be considerably more
> complex than needed to interpret a self-defining identifier.
> 
> d/
> -- 
>  Dave <mailto:[email protected]>
>  Brandenburg InternetWorking <http://www.brandenburg.com>
>  t +1.408.246.8253; f +1.408.850.1850





  [reminder: [email protected] for non-technical discussions, please]