[rescue] Re: ethernet and switches,

Skeezics Boondoggle skeezics at q7.com
Fri Apr 23 13:26:30 CDT 2004

On Fri, 23 Apr 2004, Robert Rose wrote:
> Cisco's FDDI implementation wasn't that good in the mid-90's.  At 
> "Yeah, so what"? you say, well when two boxes adjacent on the ring 
> happened to be rebooting at the same time, the damn Ciscos saw two 
> failures in the ring and shut the whole ring down! Management's 
> solution was to ditch the whole FDDI setup and go fast ethernet.  I 

Wow, that story sounds eerily familiar. :-)  Back in '95 or so at $ISP we
started moving to FDDI for our primary servers.  As it happened, Xyplex
convinced our PHB to look at their stuff, and given that it was (on paper)  
newer, faster, and way cheaper than Cisco, we gave it a go.  As I recall,
it was a very early Xyplex 9000 chassis and we were to fit it with the
route processor, Ethernet and V.35 serial cards, and the FDDI/CDDI ports
all integrated.  [Interesting aside: I think this box used the 68060 as
its main processor...]

Their 8-port CDDI switch was fine - as long as you only had 6 stations
active.  Fire up a 7th machine and the thing went completely to hell.  
That was a major drag.

But their early BGP implementation was terribly buggy.  They actually sent
three engineers up to visit us for a week, with the source code on a
SPARCbook, and sat with my mentor, boss and local guru Joey in the machine
room, debugging the thing.  We'd be in the machine room and overhear stuff
like "Uh, guys, that netmask comparison is byte swapped there - that might
be a problem."  "Y'know, you probably want to use an _unsigned_ long
there..."  "It'd sure be nice if routing didn't actually come to a
complete halt while receiving updates from a BGP peer..."

It was really cool that they actually sent the team up to work with us,
but it was pretty clear from looking at the state of their code that the
product was way too green for our environment.  ISPs in those days were
like torture testing chambers... :-)

Anyway, after about six months we eventually punted on the Xyplex, dropped
an early Kalpana 10/100 Ethernet switch in to replace the FDDI switch, and
went with a Cisco 4500 to handle the routing chores.  But when it was
working, the switched FDDI network gave terrific throughput between our
SS20s and the NetApp... as long as only six of them were plugged in at

Ah, the good old days. :-)

-- Chris

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