Peer-to-Peer
Local Networking Using CrossOver Cables
by: Tom Anderson
Ever need to make a quickie connection between two computers? There
are many different ways this can actually be accomplished without
having to set up a bona-fide network.
In the early
laptop days, there was a piece of software called LapLink which
permitted users to connect their laptops to a desktop or another
laptop computer via serial or parallel port cable.
These days,
most business laptops come configured with a PCI Ethernet card already
installed. Travelling with your buddy on the train? Need to share
a critical file and you don't have 35 diskettes to transfer that
huge Powerpoint presentation you've been working on? You can easily
create a quick peer-to-peer network without any fancy hardware or
software.
You just might
save yourself a bundle of headaches if you keep a CAT5 cross over
cable in your laptop bag.
A Cross Over
cable is a special Ethernet cable with the sending and receiving
wires switched on opposite ends. When two computers are connected
with this cable in the normal RJ45 port, you have the ability to
create a local workgroup style network between the two machines.
This of course is not a replacement for a normal network connection,
but can be a great way to 'hop' large files between two machines.
You must change
a couple of network settings, but they are not difficult if you
take a couple of minute to understand what is going on. We will
use a Laptop and a Desktop as our example machines in this example.
Each machine will be running some variant of the Windows operating
system other than Windows NT Server or Win2000 Server.
You will need
to start by getting into the Network Neighborhood settings. Either
right click on the Network Neighborhood icon and select properties
or go through the control panel.
On machine 1,
check to see if you are using DHCP. DHCP will not work in a cross
over connection and you will need to set a static IP address. We
will change the IP address settings on either one (or both) machines
to use similar IP numbering schemes:
IP Scheme: Make sure the first three octets are the same and the
last octet is different
Example:
Computer 1:
192.168.1.100
Computer 2: 192.198.1.101
The subnet mask
entry must also be identical on both machines.
Example: 255.255.255.0
The Domain or Workgroup must also match between the two machines.
Close the network
neighborhood and you should be prompted to reboot. Make sure the
computers are linked using your special cable. After the reboot,
go to the network neighborhood of one of the computers. The other
machine's network name should be visible to you!
Cable
Drawings
Network 10/100 baseT cables use 8-conductor, unshielded twisted-pair
(UTP) wire. Category 5 wiring should be free of tight kinks and
should be protected from pinches caused by fasteners, staples, cable
ties, etc. Loose excess cabling must not be coiled up in loops.
A cable from the hub to a PC may not exceed 328 feet in length.
Standard
Cable
 |
Standard
cables are used to connect PCs to the network hub. |
Crossover
Cables
 |
Crossover
cables are designed to connect hubs together, expanding the
capacity of a network. Crossover cables may also be used to
connect two PCs together without the use of a hub. |
RJ-45
Diagram
 |
10/100
baseT cables use RJ-45 connectors on the ends. The following
diagram shows how to determine the pin numbers on the connectors. |
|
