Subject: From Tag syntax

From: Henning Schulzrinne <[email-masked]>
Date: Wed, 02 Feb 2000 09:07:50 -0500

I'm trying to reach closure on a minor syntax issue.

Currently, the "tag=" parameter is a hexadecimal string (plus dash).

It has been proposed

Advantage of the change:
- one fewer syntax type to worry about;
- currently, the similar-in-spirit Via branch parameter is a token, so
this would unify the two;
- makes it easy to encode information strings as base64;
- higher information density (base64 vs. base16)
- it's easy to forget this little hex limitation, so implementations may
need to be "forgiving" in any event if one major one gets it wrong;

Disadvantage:
- it's a change from RFC 2543 and not backwards-compatible.

Questions:

1) If you are an implementor: does your implementation in any way depend
on tag being hexadecimal?

2) Any other opinions?

Thanks.
-- 
Henning Schulzrinne   http://www.cs.columbia.edu/~hgs

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From: Henning Schulzrinne <[email-masked]>
Date: Wed, 02 Feb 2000 09:21:07 -0500

> Currently, the "tag=" parameter is a hexadecimal string (plus dash).
and forgot to add:

to change this to "token" instead (which is a superset of the
hexadecimal + hyphen syntax currently allowed).

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From: Jonathan Rosenberg <[email-masked]>
Date: Wed, 02 Feb 2000 09:58:27 -0500

I also want to add that we'll be taking a poll on this at the next
bakeoff. We don't want to make this change if implementations are
adversely affected. So long as none are, I think this change is good
(our implementation doesn't depend on hex either).

-Jonathan R.

-- 
Jonathan D. Rosenberg                       200 Executive Drive
Chief Scientist                             Suite 120 
dynamicsoft                                 West Orange, NJ 07052
[email-masked]                     FAX:   (732) 741-4778
http://www.cs.columbia.edu/~jdrosen         PHONE: (732) 741-7244
http://www.dynamicsoft.com

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From: "Adam B. Roach" <[email-masked]>
Date: Wed, 2 Feb 2000 11:02:20 -0600 (CST)

>on tag being hexadecimal?

Ours does not. While helping another team to debug what was going
on at the most recent bakeoff, we discovered that at least one
implementation sends back a 500 class message when they receive
a tag which contains non-hex. However, it is also worth noting
that this problem surfaced with *only* one implementation -- so,
we can probably assume that all of the implementations at the
bakeoff except for one accepted non-hex tags.

I'm all for allowing the tags to be tokens.

-- 
Adam Roach, Ericsson Inc. |  Ph: +1 972 583 7594 | 1010 E. Arapaho, MS L-04
[email-masked]   | Fax: +1 972 669 0154 | Richardson, TX 75081 USA

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From: Emmanuel Bertrand <[email-masked]>
Date: Wed, 02 Feb 2000 18:39:58 +0100

[snip]

> on tag being hexadecimal?

Not at all in our case.  So, a token is perfect for us too.

Manu.

--
Emmanuel Bertrand
mailto:[email-masked]
http://www.indigo-software.com

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From: Sunitha Kumar <[email-masked]>
Date: Wed, 02 Feb 2000 12:12:03 -0800

Our implementation does not have  the hex limitation, for the Tag field.

regards
sunitha

--
Sunitha Kumar
Software Engineer
Vovida Networks
(408) 957 - 6374