Re: [urn] URI Scheme with Complex Equality Rules

Hi Randy,

Based on a skim of your use case, I can't yet see why minting a URI scheme
would not work.

opcid://authority/parameters

The authority here would be the DNS name or IP address, and the definition
of the scheme could establish that you wanted case insensitive matching for
the parameters (where the context would be stored).  Is there something in
IEC 62541 that would make this approach unviable? I admit that  I did not
spend any francs to get it, so I don't have examples of what the context
might look like, so if you have examples you can share, that would be
useful.

Note that while URNs are guaranteed to be unique across the lifetime of an
identifier, your scheme doesn't seem likely to want that, as it is relying
on the DNS and IP address assignment, neither of which guarantees that
property.

regards,

Ted

On Fri, Aug 26, 2022 at 1:47 PM Randy Armstrong (OPC) <
randy.armstrong@opcfoundation.org> wrote:

> I am sending this issue to this email as per the suggestion in RFC 8141.
>
>
>
> The OPC Foundation (https://opcfoundation.org) has a need to uniquely
> identify OPC UA (IEC 62541) network resources but we do not want the
> complexity that comes with the various URN schemes.
>
>
>
> Specifically we need:
>
>
>
>    1. Equality checks with case-insensitive string comparisons;
>    2. Human readable strings with uniqueness provided by a DNS name or IP
>    address (always lower case).
>    3. A valid URI.
>    4. R/Q/F components not allowed.
>
>
>
> We have been using urns of the form: urn:<dnsname>:<additional context>,
> however, this is not technically allowed by the URN RFC.
>
> We do not want a syntax that needs to be parsed before any comparison can
> be done.
>
>
>
> We could submit a request for our own nid but we don’t really have any
> syntax requirements other than the dns name and the case-insensitive string
> comparisons.
>
>
>
> What is the best way forward?
>
>
>
> Regards,
>
>
>
> Randy Armstrong
>
> OPC Foundation
>
>
>
>
>
>
>
>
>
>
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>