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An Educators
Guide to School Networks
This site will help you network your computers in your school.
Learn about the basic types of networks, communications protocol between
computers sharing a network, hardware needed for networking, how to cable
your network, and configuration of your network.
A
Guide to Networking a K-12 School District
This guide provides a step by step approach to networking a school
or district for teachers, technical coordinators, and administrators. It
provides information about many topics relevant to designing a district
network. It presents information about the background work to be done such
as developing a technology plan. It offers details a description about
how to develop network plans for the district. It lists many of the common
pieces of networking equipment used. It concludes with a discussion about
future planning. It also includes a comprehensive set of appendices including
samples of Local Area Networks (LANs), Wide Area Networks(WANs), technology
plans, and acceptable use policies.
Consortium for School Networking
This organization serves as the premier national voice for promoting
use of the Internet and telecommunications to improve K-12 Learning.
Learn about the mission, audience, and goals of CoSN.
A Guide to
Networking for K-12 Schools
This web page will provide basic networking information and planning
assistance for technology coordinators and others involved in building
networks for K-12 schools.
School
Networking Resources
The Northwest Educational Technology Consortium (NETC) is operated
out of the Northwest Regional Educational Laboratory (NWREL) and is one
of six federally funded Regional Technology in Education Consortia (R*TEC).
The national program was established in the fall of 1995 to help states,
local educational agencies, teachers, school library and media personnel,
administrators, and other education entities successfully integrate technologies
in K-12 classrooms, library media centers, and other educational settings,
including adult literacy centers and teacher education programs.
The extension of SummitNet (Montana's state government and education network)
to the county seats throughout Montana provides an opportunity for rural
school districts to obtain bandwidth in the 56 Kbps and T1 range for Internet
access and access to state government and university system resources.
Resources To Be Used When Creating a School Network
| Champaign and Urbana Districts |
| Mahomet-Seymour District |
| NCSA |
| K-12 School Networking Project |
| US Department of Education |
Important
Networking Terms:
More commonly we see client/server networks. These networks have storage
devices on the network that may hold data for users to share. If
you have worked on a client/server network, you have probably heard
the term file server used in reference to these storage devices. A client
may use the network to connect to one of these storage devices and
get some documents to view or edit.
1. The simplest topology is the bus. In this layout, the network
begins at one end and then connects to each machine.
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2. The next topology is the ring. It is very similar to the bus,
except that the two ends of the network connect to form a complete ring.
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3. The third basic topology is the star. In this layout, the network
designer designates one or location as the center of the star. They place
special equipment called a hub at this point and then run connections from
each of the machines to the hub.
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Protocol A protocol is a standard for how devices communicate. Protocols can be broken down into layers. For example, physical protocols specify things like voltage levels on wires, while network protocols might specify how a client might request a re-transmit of some data that it needs. A group of protocols that work together is called a protocol suite. An example of a common protocol suite is TCP/IP, which defines communication on the Internet.
Fast Ethernet This
is a new enhancement of Ethernet that runs at speeds of 100 Mbps, ten times
the rate of original Ethernet. Known also as 100baseT, it
requires that the wiring it runs over be category
5 (cat 5) wiring, a higher quality than the cat 3 used by normal Ethernet.
The equipment needed to use Fast
Ethernet is also more expensive than normal Ethernet,
and although the prices are dropping, it is most likely too expensive for
schools to install initially. Like
10baseT, it connects as a star topology and has
a 100 meter maximum length restriction. This allows a district using cat
5 wiring to begin with 10baseT and later
upgrade to 100baseT without replacing the wiring.
A few technologies for networking the WAN
WirelessWith the phone company charging on a monthly basis for any network services it provides, other options apart from the phone company may be cheaper. One approach is to use wireless communications to connect multiple buildings. Offering high speeds and minimal or no recurring costs, these technologies deserve a good look. When compared with the phone company solutions, the up front costs are high, but over time this cost can amortize to the point where it is cost effective. Wireless may require expensive towers to clear natural and man-made obstructions around a school because all wireless communications require a clear line of sight between the transmitting and receiving equipment. Figure 3-9 shows the basic configuration of a wireless network.
Wireless technology uses one of two methods of
communication, either lasers or microwaves. Laser technology offers higher
speeds, but shorter ranges of only a
few hundred meters. A more significant problem
is that most lasers operate in the infrared spectrum and most conditions
that block visible light such as rain, fog,
or any other physical obstruction also block
the laser. Due to these problems, lasers are not particularly useful when
trying to reliably connect multiple buildings.
Microwave communications are, on the other hand,
immune to many of the problems that plague lasers. They are immune to most
weather conditions and can
travel much farther distances.
Most microwave equipment that a district will
use operates in one of two freely available unlicensed spectrums of the
radio frequency band. The advantage is that
it requires no licensing with the FCC. Unfortunately,
this also means that other equipment can also use the same frequency and
can cause interference. However,
the equipment uses techniques to avoid this interference
from causing problems with the information being sent across the connection.
Plain Old Telephone Service (POTS) Just as its name implies, this technology relies on standard phone lines to connect schools. Using current analog modem technology, this service can run at speeds up to 28.8 Kbps in each direction. It is a cheap and usually easy way to get a machine connected to the Internet quickly. It has low start-up costs and low monthly rates. If an extra phone line is already available, the school can reuse it with no installation charge. An office can even share the line because it is only connected when it is in use, although this is not recommended. An ISP will need to provide Internet connectivity, but these are usually available at reasonable rates as well.
Satellite For districts located in remote areas, where other technologies are prohibitively expensive or unavailable, a satellite connection is a viable alternative. With this technology, a district buys a satellite dish and the necessary hardware needed to connect it to a network. A building then has a 56 Kbps downlink connection. As in the hybrid cable tv solution, satellite is an asymmetric solution and the uplink rate is only 9.6 Kbps. The initial equipment cost is about $15,000 for the satellite dish and equipment, and the monthly rate is about $800/month. A faster option is also available, with the downlink running at 115 Kbps and the uplink running at 19.2 Kbps, for about $1200/month. These rates are high when compared with other solutions, but in some rural areas this may be the only option.
The equipment is available from Intellicom. Besides
providing the equipment and network, they act as the ISP. This can save
a district money that they would
normally need to connect to the Internet. Additionally,
aware that the uplink rate is insufficient to support a district web server,
they provide space on their web
server for the district to use. They can be contacted
at (510) 353-0102. They also have information about their products available
on their web site at
http://www.vsat.com/.
Channel space on an existing cable-TV system Works in some places where cable systems are set up with excess capacity, requires cable company cooperation, and will likely incur regular fees. Requires special modems that need to be matched to cable company specifications.
Network Equipment:
Repeater Repeaters are the
most basic type of active network equipment. They operate solely at the
physical layer, receiving a signal on one port, or connection,
and rebroadcasting it on all of its other ports.
They can extend a network beyond the limits imposed by the wiring by boosting
the signal level.
Hub A
hub is a device that serves as the center of a star topology network like
10BaseT. It is also called a concentrator. Hubs come in two basic
models:
stackable and modular. Stackable hubs have a
fixed number of ports available to connect network devices. There are 4-,
8-, 12-, 16-, and 24-port models. Modular hubs offer a great deal of flexibility.
It is possible to have an Ethernet network, AppleTalk network, and token
ring network running in the same hub. Greater flexibility also translates
into higher costs, and modular hubs do cost more.
Bridges
Bridges operate at a higher level than repeaters, working at the data link
layer and looking at the actual packets that are on the network. When they
receive a packet, they store the entire packet
in memory, verify its correctness, and retransmit it on the correct port.
This allows them to connect different types of
Ethernet networks together such as a 10baseT
and a coax network. They also reset the "3-4-5 rule" for each port, making
each port its own network. This is
because it stores the entire packet and rebroadcasts
it, isolating each port from the others. Like switches, they look at the
destination of the packet and only send it
to the port where the destination is located,
reducing traffic on the network.
Routers Routers are devices that connect networks to other networks. They select what data will go outside the network and what data will stay inside the network. In a large network, several routers might create a path for network traffic to follow to get to a specified destination. A router of some kind is needed for Internet access from a local area network.
A router is also used to hook up dissimilar network protocols. If you have a large 10BaseT network and you want to connect a few users on an old token ring network, you can put a router in between them. The router will handle the translation between the protocols.
NICs The network interface card (NIC) is an add-on board that serves as the connection between the client computer and the network infrastructure. In other words, to hook all your computers together, a special electronic circuit card called a NIC goes inside each computer. That's where you plug in the cable that connects the computer to the network. Some computers come with built-in network interfaces and do not require an additional NIC. You will find that NICs vary in cost depending on the type of protocol they support. For example, 10BaseT NICs are inexpensive when compared to FDDI NICs.
Cables:
Unshielded twisted pair (UTP) wire It
has become the most common media type for LANs today. Unshielded
twisted pair has been used by telephone companies for years to attach phones
for local service. Today it is used not only for voice applications, but
also in data-network applications.
Fiber optic cable Fiber optic cable uses light instead of electricity to carry data. This accounts for two of its advantages: (1) Data can be moved at extremely high speeds without generating interfering radio frequency signals and (2) Data transmission is not affected by the proximity of electrical equipment or high-voltage transmission.
Coaxial cable Coaxial cable is probably the most well-known type of cable. The term coaxial denotes a class of cable that has several layers of material surrounding a common axis. Today, the most common use of coaxial cable is for video distribution.
Wireless media Wireless systems have special applications in interbuilding communication and might be useful in your campus or district networks. They use radio or microwave transmission for data networks.
I believe the most appropriate cable to use in a school would be Unshielded twisted pair (UTP) wire. The cost of UTP's are most cost effective for schools and most schools are already equipped with the cables for their phone systems. There are also less trade-offs than other cables (expense, reliability, and performance) and provides the features most schools would need for their voice applications and data-network applications.
Wazza's School Computer Network Infos.
Networking and intranet explanations and suggestions for schools
Types of School Computer Networks: All schools today are installing the ethernet computer networks, which is an international, non-proprietry standard.
Types of Network Cable: The recommended school standard for network cabling is Unshielded Twisted Pair (UTP). UTP can be upgraded without having to replace your cable.
Wireless School Networking: Wireless networking connects one site to another using radio transmission. It is an expensive option, but is good for sites which are difficult to cable because of their layout or the way they were constructed.
School
Intranet Resources: Intranet refers to tools and protocols normally
associated with the Internet. Students using an intranet are able
to browse web sites and send e-mail, just as if they were on the internet,
though their computers may have no connection to computers outside the
school. This allows for complete control over the content the students
are accessing on the computer.
Networking Design and Research Center
This site is helpful for those wanting to learn about the complex world of networking computers. There are numerous links to networking resources, networking terms, and networking category listings.