20402 routing entries (renumbering)

Tim Streater t.c.streater at dante.org.uk
Sat Apr 16 01:01:38 UTC 1994

Renumbering workstations in principle *is* a no-brainer. But there are
always wrinkles. And if those workstations are running a particle
accelerator (as when a year or so ago I coordinated some renumbering at
SLAC), you better have a damn good reason for doing it. A $20M facility
running 7*24 expects good reasons for you to possibly screw it up, and
their operational philosophy is to assume you will.

I was able to renumber two largish groups of machines (200 or so in each),
with quite a bit of coordination needed, and because of the various
overlapping schedules it took a while before I could even start. Then, for
each group I had to assemble numerous experts (Macs, Amigas, PCs, Next,
RS/6000, Sun, Ultrix, VAX, Cisco). Luckily we had a good database of
workstations so that I could tell the platform experts which machines were
going to be involved. In some cases changes had to be backed out a couple
of times because of something the platform experts forgot (or didn't know

Now, can you imagine the conversation I might have had if still working
there and SLAC agrees to exchange its class B (with about 1k out of 64k
addresses assigned) for some number of class C:

Me:     SLAC has to renumber!
Users:  Again? OK Tim - but why? And what's in it for us?
Me:     (explanation of routing overload deleted)
Users:  So you are saying that of the 20k or so addresses in routers,
        SLAC renumbering saves just one entry?
Me:     Err, yes.
Users:  Don't ring us, we'll ring you!

As Marty says, there is (unfortunately) no carrot - and users resent the
stick. You apply the stick too often and you are out the door, either as an
external provider or internal expert. Users barely (in some instances) know
what an IP address is. They expect the network to be like the phone or
power outlets; you just plug in where you happen to be. If we expect
renumbering and provider-based addressing to be feasible, it seems to me
that w/s vendors need to provide powerful tools to enable *transparent*
*on-the-fly* renumbering - else it won't happen. And even if they do (and
where's the carrot for *them*?), it will be quite a while before such tools
are ubiquitous enough to make the process always easy. Should we be working
with vendors in this area?

Now will you all *go* *home* - it's the weekend, damnit!

Tim Streater, DANTE.    t.c.streater at dante.org.uk   +44 223 302992

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