This actually works reasonably well as long as you don't try to cram 20Mbps
of data through it in aggregate.
The problem that one particular provider had was trying to do this
full-mesh AND ignoring the fact that Ethernet isn't really 10Mbps; its
more like 5-6Mbps when you take the duplexing issues into account. Now add
the collision domain problems to this (you really don't have a 3000-mile
collision domain; its "faked" in the translation) and limited buffering and
you can see where some problems show up really quickly, especially when you
sell resale T1s to people and don't upgrade the backbone to meet the
increasing sales of circuits......
If you only mesh the places you need to talk to from one point to another
and use a better exit technology at exchange points (allowing an aggregate
data rate > 10mbps) it works quite well. Try to go "cheap" and use the AUI
interface everywhere and you get a different result.
And I know a provider that despite realistic expectations of the technology,
still experience serious problems with everything that Sean mentioned. 50%
of all problems were caused by inadequate buffering, and the other 50% were
caused by PVC's either dissappearing, or being re-routed around the wrong
end of the country.
(Gee, 250ms from San Francisco to San Jose...it's taking the east coast route
> -- mixed-media bridging (NetEdges, FDDI/Ethernet bridges)
Netedge <> Ethernet works quite well (far better than RETIX<>Ethernet.)
No argument on the Retix's.
Netedge<>FDDI has been reported to have the problems you listed, and more.
not quite there yet, no.
> Finally, why is it that most vendors never test their products in
> a serious battlefield environment like an ISP of size medium to huge?
> These places tend to be excellent worst-case testing grounds.
That's a good question...
What are you talking about? They do a series of stress tests designed to
push the equipment to it's utmost capabilities in their state-of-the-art