Re: [Sip] INFO considered harmful

["Adam Roach" <adam@dynamicsoft.com>]

From: "Dean Willis" <dean.willis@softarmor.com>

> > http://www.jdrosen.net/papers/draft-rosenberg-sip-info-harmful-00.txt
> > http://www.jdrosen.net/papers/draft-rosenberg-sip-info-harmful-00.html
>
> Jonathan and I have had "extended discussions" on this. I'm more
> inclined to think that INFO needs specifications for specific usages,
> much as we use "events packages" for SIP Events (SUBSCRIBE, NOTIFY). In
> my own completely non-original way, I call these "INFO Packages".
>
> Anybody else have a third opinion?

Not exactly a third opinion, but here goes: I agree 100% that something must
be done about the current state of INFO. So far, with the one well-known
exception, INFO has just served as a way that people can throw random crap
in the body of a meaningless message so that their implementation has no
chance of interoperating with any other, but can still claim 100% compliance
with IETF proposed standard documents. (The embarassing thing is: they're
not lying.)

I'm not so set on which of the two actions (packages, or restriction to
SIP-T) is correct. However, I find a couple of arguments that Jonathan makes
in the draft extremely compelling:

1. The INFO spec does not actually define any semantics. It
   only says "this acts like a BYE, except that it doesn't tear
   the session down".

2. Any new feature that INFO enables could be defined
   by adding a new method; and, the existence of the INFO
   spec does not provide any ease over doing so.

I'll add a third: despite INFO being an RFC for more than two years, there
have been no additional internet-drafts that suggest alternate legitimate
uses for this method. If it were useful enough to warrant saving, certainly
at least one additional use would have been identified by now.

These arguments would seem to indicate the path of deprecating INFO except
for its only currently approved purpose: ISUP transfer. I can probably be
swayed, but haven't heard any counter-arguments yet.

/a

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