[MLB-WIRELESS] Cat 5 Problem

Jason Brice Jason.Brice at kiandra.com
Tue Feb 18 16:06:52 EST 2003

You're making crossover cables there, chief ;) or at least one end of them...

Not that it makes much difference, but most cables will subscribe to the 568A standard with the green and orange pairs reversed (from the perspective of your diagram)

hehe, you're just shy of autonegotiate after that shitty HP switch gave us hell at Kiandra.

Autonegotiate is absolutely essential for large networks at the access layer (mobile clients, laptops, visitors, etc.) but I agree that in the core you need to know whets going on between routers/servers/switches/trunks etc. you want to set your speed and duplex manually. 

hows it going anyway Ben?

jason brice
senior network engineer
kiandra system solutions
level 9, 455 bourke st melbourne vic 3000
(t) +61 3 9600 1639
(f) +61 3 9600 1656

-----Original Message-----
From: Ben Ryan [mailto:ben at bssc.edu.au] 
Sent: Tuesday, 18 February 2003 2:49 PM
To: melbwireless at wireless.org.au
Subject: Re: [MLB-WIRELESS] Cat 5 Problem

> Hey all,
> Short story, 35m of cat 5, should be running at 100mb, XP wont 
> recognise it unless I set the secondary machine to 10mb.  Primary can 
> remain at 100. There is a switch in the middle.  This works fine... 
> It's only 35m so there couldn't be that much loss or whatever it's 
> called on ethernet. I want 100 to 100

Check your pairings on the cable.
Incorrect pair/pin selection can prevent you from being able to communicate at 100 mbit. Even if the lights are on, packets don't seem to be received. Check the colour-pin connections in the plug against a standard.

Also, almost always, autonegotiate is a BAD BAD idea.
Manually specify the speed at both ends - pref 100/Full Duplex.

there are two (?!) main standards.

With tab facing down, cable on your end and the plug-end away, using T568B (my pref) you should see (left-to-right)

Orange/White  Orange  Green  Blue  Blue/White  Green  Brown/White  Brown
  pin1        pin2     pin3   pin4   pin5       pin6    pin7        pin8

(don't trip on the standards ;))


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