# Re: reply to various on URNs and URLs

Michael Mealling (ccoprmm@oit.gatech.edu)
Mon, 21 Feb 94 12:11:09 EST

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    From: ccoprmm@oit.gatech.edu (Michael Mealling)

    Message-Id: <199402211711.AA03209@oit.gatech.edu>

    Subject: Re: reply to various on URNs and URLs

    To: jcurran@nic.near.net (John Curran)

    Date: Mon, 21 Feb 94 12:11:09 EST

    In-Reply-To: <9402211406.AA09228@mocha.bunyip.com>; from "John Curran" at Feb 21, 94 9:05 am

John Curran said this:
> ] From: William Manning <bmanning@is.rice.edu>
> ] Subject: Re: reply to various on URNs and URLs
> ] Date: Mon, 21 Feb 1994 07:56:31 -0600 (CST)
> ]
> ] John, if the implementation is via DNS TXT records, then you already
> ] have a TTL method built in.
>
> Implementation via DNS may be a major mistake... DNS administrative
> authority realms do not overlap with URN authoirty realms, and DNS is
> not exactly dynamic at this time.

I personally don't mind using some portion of DNS for this but I would
like to keep the design generic enough so that it works when at some
point in the future we can decommission DNS and not have everything else
break.

> But, yes, I think that we need to realize that any bindings (URN -> URL,
> URC -> URL, etc.) need to have an associated lifetime set by the publisher
> or we run the risk of returning information which differs from the intent.

I agree %100. I don't think it's brain surgery though. The way I see
it a URN by itself is just a rather short URC. Put a TTL field in there
and you have your URN + TTL binding:

URN:blablalba
TTL:1m0d0h0m

In the same way a URL is also just
a very short URC, add a ttl and you have your ttl for that URL.

Title:Time of Day Server
URL:gopher:blabla
TTL:0

A URC with both a URN and a URL can have different TTL for each item.

URN:bla
TTL:1md12
URL:gopher:bla
TTL:0

Also, if you were to have a TTL field as the first line BEFORE the URN you could
say that that TTL was the expected TTL for the whole URC (although I
wouldn't trust it for have a millisecond):

TTL:1d
URN:bla
bla:
bla:

-MM

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