[vortex] Cable lengths over spec (was: Re: HELP needed: Cross-over connection)

Ruben van der Leij ruben@blacklisted.nl
Fri Feb 7 14:54:01 2003


+++ Bogdan Costescu [07/02/03 18:32 +0100]:

> > Anyway, I have changed the cable and it seems that the
> > longer the cable is, the better the connection works.
> 
> Huh ? You've discovered the holly grail of networking :-)

Which brings me on a associated topic. Very long cables.

One of our locations consists of two building, some distance apart. The
connection-room (where all outside connections terminate) is in the far
cornet on the ground-floor, and thanks to Murphy our suite is in the other
building on the third floor, and front of the building.

A cable from there to here measures as 118 meters. Which is too long.

But 118 meters of fiber and a pair of transceivers is expensive. I assume
that if I would ask them to put in a cat-5 cable things would work as
usual. But at which point will things break? How much of a margin is there
in the specs? (the length-limit has to do with collision-detection, I guess.
But on a full-duplex there will be no collisions.) Does using full-duplex
give you extra room for over-spec cables? 

Any experience on that? And any theory to back that? :)

-- 
Ruben van der Leij

Dinner suggestion #302 (Hacker's De-lite):
	1 tin imported Brisling sardines in tomato sauce
	1 pouch Chocolate Malt Carnation Instant Breakfast
	1 carton milk