Subject: [Sipping] Comments on draft-moran-sipping-filter-arch-00

From: "Eric Burger" <[email-masked]>
Date: Fri, 7 Jun 2002 09:11:44 -0400

In general, even I can endorse the draft :-)

The concept of a standard set of methods to set parameters in the
notification server is rather useful.  This draft exemplifies the value of
object-oriented methods.  You might want to mention that in the draft.

I have some comments and some editorial nits.  First the comments.

3.1.1 Current time
Is it meaningful to have millisecond accuracy for something that can easily
take 500ms of one-way transit time?
In the 3G case, the endpoint does have a pretty good sense of network time.
For that matter, 2G handsets have a good sense of network time.  However,
can we rely on this in the general case?  More importantly, is there a use
case for a current time parameter?

3.3 Operators
Do all servers have to support all operators?  If they don't, and I don't
see how one could require them to, then do we need to differentiate between
"I recognize that operator but I don't support it" versus "I don't get what
you are trying to say."?

3.3.2 Comparison and Logical Operators
For Has-changed-by, I would propose the default units are specified by the
package.  In the appendix, this corresponds to the "location-radius-meters"
attribute.  Otherwise, I would suggest passing the value and units as opaque
strings.

One option is to link the tag to a value, such as
'<interval>900s</interval>'.  This has the benefit of saying what you mean.
It has the drawback of being long.

Another options is to specify the value in the VoiceXML way, such as
'<interval value="900s"/>'

'<interval seconds="900"/>' is rather grating and makes for a big DTD if you
wanted to also allow <interval minutes="15"/>, <interval days=".01041667"/>.

3.3.3 Time-based Logical Operators
I would suggest that it would be more understandable to say that "Every X"
means repeat the notification every X period until we hit the Expires time
of the original subscription, while "Every X 0" means report once.  This
follows the meaning found for the Expires header, as well as making sense as
you read it.  That is, when I say, "Please check my e-mail every 5 minutes"
I expect the system to check my e-mail every 5 minutes until I say stop.  I
don't expect the system to check my email 5 minutes from now and then stop.

The following are typographical errors.

3.1.4 Error
s/Code, and String/Code and String/

3.3.1, 3.3.2, 3.3.4, 5.2, 9 [7], 9 [8], Annex A, Elsewhere
There seem to be non-7-bit ASCII characters throughout the document.  I
think you have some em dashes and curly single & double quotes.

4.1 Normal
s/are used. If no, filtering rules/are used. If no filtering rules/

10 Author's Addresses
This section should be "Authors' Addresses".  Also, your e-mail is much more
important than your (missing) telephone number :-)

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