links on the blink

William Allen Simpson bsimpson at
Tue Nov 14 15:29:36 UTC 1995

> From: "Mike O'Dell" <mo at>
> by the time we get anything that new installed, it had better be able
> to go a lot faster than OC12 or we'll be right back in the same pot
> on the day we put it in service.
I disagree with this position.  The fibers installed to do OC-12 will
certainly do OC-48 when it becomes available.  And the next x4 jump as

> Native packets over SONET is indeed The Right Thing To Do.
As author of PPP over SONET/SDH, I get queries from time to time about
when this will be available.  There are at least 2 unannounced products
in development.  I expect they will begin delivering OC-12 next summer,
and OC-48 the following year.

> The more interesting question is what is the difference between
> switching and routing, and what is the role of each as the networks
> grow in size, capacity, and bitrate. (And no, I don't mean cells.)
I also expect that _routing_ at that rate is the hard part.  Maybe being
a link kind of guy, the link parts just look easier to me.

I expect _switching_ at that rate to be even harder than routing if they
are cells; the times are just too short.  But the usual packet size
isn't much more than 3-6 cells, so the scale isn't as much better as we
would hope.

We tried to make 1500 bytes ubiquitous with PPP, but too much host
software still uses 512 bytes anytime it thinks the destination is
"remote", even when there is 1500 bytes end-to-end.

Bill.Simpson at
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