Re: globally unique identifiers for lightpaths?

[Freek Dijkstra <fdijkstr@xxxxxxxxxxxxxx>]

Ronald van der Pol wrote:

> Two possibilities, I think:
> - central repository
> - random number

For scalability reasons, I prefer the latter.

As to ensure global uniqueness, Ronald proposed timestamps. Another
method is to use a hierarchy and use DNS, AS numbers, or -as Ronald
suggested- location of the nearest city. This reduces the global
uniqueness constraint to a more local uniqueness constraint, which is
often manageable. As an example, put the timestamp and your GPS
coordinates together, and as long as your not standing to a big random
generator, you are pretty sure it is a unique number.

- RDF uses URIs as unique identifiers, and relies on DNS + whatever the
domain name owner comes up with.
- Universally Unique IDentifiers (UUID) rely on timestamp and node ID
(See RFC 4122, ITU-T X.667 or ISO/IEC 9834-8)

Note that cities in UN Location codes
(http://www.unece.org/cefact/locode/) are country dependent. For
example, there is also an "AMS" in the United States. So this example:

> 20071205200042-AMS-CHI
> 20071206070809-NYC-TYO

Ought to be:
20071205200042-NLAMS-USCHI
20071206070809-USNYC-JPTYO

As Kevin Pointed out, these are not unique. What if we get two GOLEs in
the same city? That is not unthinkable. (The problem of 1 GOLE in more
cities is solvable. Pacific Wave can either use US-SEA, US-SNN or
US-LAX, depending on the terminating device).

I would not create a repository for GOLE codes. This has two problems:
1) Yet Another Global Name Repository. Why not use an existing one. If
UN location codes or AS numbers (not all GOLEs have IP addresses) are
not sufficient, simply use another, like their domain name.
2) We should not restrict the end points to GOLEs. While that is the
current practice, our goal is lightpaths towards end-users (at least
it's mine!). So the end points in user domains should be possible.


The discussion seems to be whether the ID should be contain information
or not. I personally don't like UUIDs, and I now think why. I never can
remember them!

The -AMS-CHI appendix are really nice. It helps me, as a human,
understand it. Why not use the domain name of the requester, rather than
the GOLE id? So:
20071205200042-amc.nl
20071206070809-uhvem.osaka-u.ac.jp


Regards,
Freek


PS: When checking the ITU-T reference for UUID, I just found that since
last month you can download ITU-T recommendations for free! That is
excellent news; with RFCs and W3C recommendations always free and the
Get IEEE program, only ISO standards have restricted access.
http://www.itu.int/ITU-T/newslog/Free+Access+For+All+To+ITUT+Standards.aspx

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