[NTLUG:Discuss] Switch Question

[Bryan J. Smith]

On Sun, 2004-11-14 at 11:29, Greg Edwards wrote:
> I agree with the underground Ethernet solution that has been mentioned. 

As much as it costs a little extra, fiber just eliminates so many
problems.  Consider 1000Base-SX (multi-mode, cheaper) or 1000Base-LX
(single-mode, more costly, longer).

> Daisy chaining hubs is not a problem.  IIRC 400-500 meters is the correct 
> length for hub to hub

10/100Base-T is 85m each segment, assuming a repeat (hub).  With a
switch, you can probably go 170m.

1000Base-T[4] is debateable, and there are many constraints.

> with something like 1400-1500 meters as the max overall length between
> routers or hosts,

> i.e. no more than 3 hubs between routers.

That was the 10Base rule -- up to 4 hops (3 levels of cascaded hubs).
The 100Base rule is only 1 hop, which means not even 2 levels of
cascaded hubs (because that could mean 2 hops).

Of course this changes with switching.  Because you're no longer
repeating, but typically using a store'n forward.

> I will toss out another point to keep in mind.  You'll want to lay the 
> cable inside of a water tight conduit, not just wire under ground.  While 
> your laying the cable you might want to consider running a few extra lines 
> for future expansion.  Feeding more cable through a conduit, without 
> digging it up, is possible, just not fun ;)

Always an excellent suggestion.  Never know if you need to augment or
replace.

-- 
Bryan J. Smith                                    b.j.smith at ieee.org 
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