Subject: [Ecrit] [issue6] 'Authority' Attribute in LoST Response

From: Hannes Tschofenig <[email-masked]>
Date: Mon, 05 Jun 2006 17:56:30 +0000

New submission from Hannes Tschofenig <[email-masked]>:

ECON-IRIS defined an 'authority' attribute in the response message.

This attribute provides information about the authoritive source of the mapping 
data. 

Question: Is it useful to provide such information in a LoST response?
What information would be a good identifier for an authoritive source?

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assignedto: hannes
messages: 8
nosy: ecrit, hannes
priority: critical
status: unread
title: 'Authority' Attribute in LoST Response

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From: Andrew Newton <[email-masked]>
Date: Mon, 5 Jun 2006 15:14:47 -0400

> What information would be a good identifier for an authoritive source?

It may useful to detect referall loops by LoST resolvers.

-andy

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From: Henning Schulzrinne <[email-masked]>
Date: Mon, 05 Jun 2006 16:03:10 -0400

I suppose it could be an IETF enterprise identifier (since these are 
free and there's already a registry).

I'm not quite sure what you'd do with this information. I think we 
talked about a "bug reporting" address, or possibly several (http:, 
mailto:, sip:, etc.), at the interim meeting, but that may be a separate 
feature.

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From: "Brian Rosen" <[email-masked]>
Date: Mon, 5 Jun 2006 16:41:54 -0400

The reason you want it is to provide a way to report an error.
I think it's essential.

I think you need a URI, which could be a website or an email address.

Brian

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From: Hannes Tschofenig <[email-masked]>
Date: Mon, 05 Jun 2006 22:47:00 +0200

Hi Brian,

> I think you need a URI, which could be a website or an email address.
I wanted to go through the interim meeting minutes where we discussed 
this type of error case as a separate item. I think it is a separate 
scenario.

I think we need to describe the use cases we have in mind in more 
detail. Andy mentioned referall loops and you another error case.

Ciao
Hannes

>>This attribute provides information about the authoritive source of the
> 
> mapping 
> 
>>data. 
>>

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From: Henning Schulzrinne <[email-masked]>
Date: Mon, 05 Jun 2006 17:21:16 -0400

> I think you need a URI, which could be a website or an email address.

That's what I suggested, except to allow multiple URIs if you want to 
easily provide multiple means of contact without having to fish them out 
of a web page. (For example, an automated checker of some kind might 
want to report problems via an email interface, rather than 
screen-scrape a web form.)

Dealing with referral loops is a very different issue and probably not 
addressed by including authority information. In some cases, revisiting 
the same server or authority may be the right thing to do (see "SIP 
spirals" for a version of that issue).

---

From: Andrew Newton <[email-masked]>
Date: Mon, 5 Jun 2006 17:49:20 -0400

On Jun 5, 2006, at 5:21 PM, Henning Schulzrinne wrote:

> That's what I suggested, except to allow multiple URIs if you want  
> to easily provide multiple means of contact without having to fish  
> them out of a web page. (For example, an automated checker of some  
> kind might want to report problems via an email interface, rather  
> than screen-scrape a web form.)
>
> Dealing with referral loops is a very different issue and probably  
> not addressed by including authority information. In some cases,  
> revisiting the same server or authority may be the right thing to  
> do (see "SIP spirals" for a version of that issue).

Just why would I want to ask the same question multiple times to the  
same server in the same seek operation?  It would seem that detecting  
referral loops would be awfully important.  The type of identifier  
used is not that important, so a URI is fine by me.  I'm not sure  
about multiple URIs.  Also, you'd need to define a much more detailed  
interface for automated checking than "here is a bunch of URIs".

-andy

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From: Henning Schulzrinne <[email-masked]>
Date: Mon, 5 Jun 2006 20:27:46 -0400

>
> Just why would I want to ask the same question multiple times to  
> the same server in the same seek operation?  It would seem that  
> detecting referral loops would be awfully important.  The type of  
> identifier used is not that important, so a URI is fine by me.

It's a bit of a stretch, so a URL that identifies the actual  
"virtual" host is probably sufficient to deal with the case that a  
single server can serve multiple levels (such as state and some towns  
within a state, but not county).

> I'm not sure about multiple URIs.  Also, you'd need to define a  
> much more detailed interface for automated checking than "here is a  
> bunch of URIs".

The idea for automated checking would be that the checker is a robot,  
but it would just generate text meant for a human, just like web  
checkers generate mail to webmaster@domain that's meant to be  
interpreted by a human.

As long as there's no particular format requirement, the URL is  
pretty self-describing, just like a link is on a web page.

---

From: Andrew Newton <[email-masked]>
Date: Mon, 5 Jun 2006 21:04:39 -0400

On Jun 5, 2006, at 8:27 PM, Henning Schulzrinne wrote:
> single server can serve multiple levels (such as state and some  
> towns within a state, but not county).

I don't understand your response.  Is the scenario you are drawing  
one where a single URL identifies a server that serves a state and  
some of the towns in the state but not some of the counties that  
hierarchically between the state and the towns?  It would seem a bit  
odd for a server that has the authoritative information to say, "you  
must first go ask that guy and he will refer you to me, and then I  
will answer your question."  Talk about bureaucracy!

>> much more detailed interface for automated checking than "here is  
>> a bunch of URIs".
>
> The idea for automated checking would be that the checker is a  
> robot, but it would just generate text meant for a human, just like  
> web checkers generate mail to webmaster@domain that's meant to be  
> interpreted by a human.

The common name for this is "spam".  I don't care if you want to do  
this, so long as it doesn't interfere with referral loop detection.  
But I do think it is overkill.

-andy