 |
| Volume 2 Issue 5 October 1997 |
Features
Interviews
Reviews |
 |
| HTINews Article - Oct97 - [HTI Home Page] |
Information Services Order Free Catalogs and Product Info [Click Message To Learn More] |
Networking in
the Home
|
Doug
Moses is a Regional Systems |
When designing Home Automation Systems for a homeowner, it is often requested that a computer network be installed at the same time. This article gives you an overview of the concepts of computer networks and how to incorporate them into your Home Automation plans.
A Quick Networking Overview
A computer network in the home is commonly known as a LAN or Local Area Network. A NIC or Network Interface Card is require to be installed in each computer attached to the network. A wire is attached from each NIC to a box called a Hub. A network Hub connects all computers together. A Network OS/Operating System is required to share information and resources on a LAN. A Network OS is software and requires proper configuration.
Selecting a Network Topology
The first step in networking is to decide upon a network topology. There
are many different types available today. The topology of a network is the underlying
hardware specifications of a network. The type of hardware you choose determines the type
of wiring, NICs and Hubs you will need to use in your design. The two most common types
for personal computers are Token Ring and Ethernet.
The Token Ring topology usually requires 2 pair 22 AWG IBM Type I or II shielded wire.
This type of topology is very expensive for home use. The cost of connecting two computers
together with this type of topology is typically over $500. This is the best topology to
use if you are connecting to mainframes.
Ethernet topology is the most common for home use. This is because it is low in cost and
uses wiring commonly found in low-voltage Home Automation designs. You can connect two
computers together with this type of topology for under a $100. 10BaseT is the standard
Ethernet topology used in Home Automation designs. This type of Ethernet requires 4 pair
24 AWG UTP CAT-5 wiring.
Installing the Hardware
Once you choose a network topology the next thing
you will need to choose are the hardware components to support the topology. The three
basic components of the network hardware are the NICs, Hubs, and wiring. A NIC is an
internal card installed in a computer and a Hub is an external box that connects network
devices or computers to the network.
Installing a NIC into your computer requires the same hardware configuration steps as if
you were installing an internal modem or sound card. You will have to determine your
computers IRQ settings, Bus type, and I/O address information. When you buy a NIC you will
typically receive a manual and software that will help you install your NIC. Some
computers come with built-in NICs or automatic configuration. This makes the hardware
setup step easier.
Many different types of network Hubs exist today. The most common Hubs connect 4 or 8
computers together. Some network Hubs require an external power supply and have to be
initialized before they can be used. You can connect several network Hubs together to
create a larger network.
When connecting computers/NICs to Hubs, you will need to install dedicated wiring from
each computer to the Hub. If you choose Ethernet as your topology with 4 pair CAT 5 wire,
you can use the same wire for both voice/phone and data/network. Four wires can be used
for your network and the remaining four wires for two phone lines. This is the typical
wiring setup for low budget projects. Phone crosstalk is usually not a factor with
Ethernet. The more common wiring configuration is to use a dedicated 4 pair wire for your
network. This leaves room for expansion and eliminates any possible network interference.
The Network OS
After you install the hardware components of a LAN you will need to
install a Network OS. A Network OS is the software layer of a network. Most network OSs
support both Token Ring and Ethernet topologies. Most computer systems sold today already
have networking capable Operating Systems installed.
You can also purchase a dedicated network OS. These software packages give you many
advanced features such as security, large network support, and remote administration. Some
of these packages also require a dedicated computer to act as a Server. A dedicated
network OS is usually expensive and not required for home LANs.
Depending upon your Network OS, your computer can be configured as a Workstation, a
Server, or a combination of Both. A network OS that allows your computer to be configured
as both a Workstation and a Server is know as a Peer-To-Peer network. In this type of
configuration you can share printers and drives easily from one Workstation to another.
This type of Network OS give the most flexibility in a small network.
So what does a LAN do exactly?
A network allows you to share devices from one computer to another. The
two most typical devices you can share on networks are drives and printers. A drive or
printer that is shared on a network is available to other Workstation computers. Shared
devices on a network can be used by Workstations as if they are locally attached.
Example: You have two computers on your network. One computer is in a bedroom and the
other one is in the living room. The computer in the living room has a CD-ROM and a laser
printer. The computer in the bedroom has no printer and no CD-ROM. You buy a new graphics
program and it comes on a CD-ROM. With a network you can install the program on the
computer in the bedroom by sharing the CD-ROM on the living room computer. You can also
print to the laser printer in the living room from the computer in the bedroom by sharing
the laser printer on the network.
Network Aware Programs
A Network Aware Program is a software program that recognizes that it is running on a network OS. Many programs are not Network Aware. These program can not be run simultaneously on shared drives. Programs that are not Network Aware can only be run from local drives. Many games are Network Aware Programs. They allow you to play head-to-head against others on a network.
Summary
For Home Automation purposes it is probably best to choose Ethernet as
your network topology. This is because it uses wiring that is commonly used by other Home
Automation devices. 10BaseT Ethernet topology uses CAT-5 wiring.
The four components to a LAN are NICs, wiring, Hubs, and network OS. The peer-to-peer
network OS is the most versatile network OS for small networks. The hardware setup of a
network requires a NIC installed in each computer. Each NIC is connected to a Hub via
dedicated wiring.
