Local Area Network technologies
Computers are useful on their own, but their real potential is as a communication and collaboration tool, and for this they need to be networked together so that data can be passed between them easily.
Cabling and network hardware
An Ethernet-based local area network is the basic technology that NPO’s should implement for setting up a network. This technology is often referred to as 100baseT or twisted-pair technology. This technology is mature and low cost. It requires cabling attaching all computers to a switch or hub, a device that regulates traffic between them. All computers should have compatible network interface cards.
For existing networks, 10mbit Ethernet networks on category 3 cabling with hubs are acceptable. For new installations, we recommend 100mbit Ethernet networks over professionally installed category 5e cabling and switches.
Organizations that are running a slower 10mbit network and experiencing performance issues may find that a simple upgrade from hubs to switches may significantly improve performance. (A hub shares the same connection bandwidth among all the computers attached to it, while a switch provides each computer with an individual, dedicated, full-bandwidth connection.)
Organizations with servers should seriously consider adding a 100mbit switched connection for the server. It possible to run mixed switch and hub networks, though this sort of architecture requires some care to make sure that the available bandwidth is being used efficiently and that there aren’t any avoidable bottlenecks. Generally, it is best to configure a network with the fastest, largest capacity device at the head end, and attach shared resources, such as servers and Internet routers, to this primary devices. Secondary switches and hubs are attached to this primary device, and then desktop computers and other network devices are attached to the secondary devices. In this way, the network bottlenecks, such as 10mbit hubs, are as far down the network as possible, allowing for maximum bandwidth to the server and other key devices.
Wireless networking
Where installation of network cable is not a low-cost option, for instance in environments where computers are a great distance apart, wireless network technology based on the Wi-Fi standard can be used. There are two common versions of this technology, 802-11b, which is a slower first generation protocol, and 802-11g which is a faster second generation protocol. Both of these technologies are acceptable in existing implementations. For new installations, we recommend the 802-11g standard. Please note that the use of wireless network technology can introduce a number of security issues that need to be addressed.
Because wireless signals are broadcast, it is possible for unauthorized users to snoop data on the wireless network. It is also possible that unauthorized users can access your organizations Internet connection, hijacking it for their own use. As a result all wireless equipment should use an encryption system to protect the network from unauthorized users. There are two common wireless network security protocols, WEP and WPA. WEP is older technology and has a number of know vulnerabilities, and is difficult to configure as well. WPA is newer, more secure technology, and is easier to setup, but is not supported by most older (pre-2002) hardware. Organizations starting from scratch should purchase WPA capable equipment. Organizations with older WEP equipment do not need to upgrade, but need to be aware of the security concerns and may decide to upgrade as a result. No wireless network should be installed without one or the other of these security protocols.
In addition, organizations using a hybrid network with both wired and wireless connections need to configure their network carefully so that both sets of connections can “see� each other across the network. Hybrid networks should use the same subnet for all client computers, which is a supported feature of most dedicated wireless access points.
Network protocols
There are a number of different network protocols in common use. Protocols are the language computers use to transmit data over a network. We recommend using the TCP/IP protocol. This is the native language of the Internet, is supported by all major operating systems, and is very flexible. We recommend that organizations use their own separate, non-routable TCP/IP network configuration. There are very few good reasons to setup up computers on the local network that are accessible from the Internet.
Rather than setting up each workstation with an individual IP address, we recommend using a DHCP (dynamic host configuration protocol) server to distribute IP addresses. DHCP servers are included with most server operating systems and network routers. We recommend that servers, printers, and other network accessible shared devices make use of static IP addresses.
Organizations using a server running a network operating system will most likely need to setup a DNS server for the internal network. DNS servers are integrated with the recommended network operating system and are required to enable most of the higher end security features. In most cases a simple bare-bones DNS installation is all that is needed for the server to operate properly.
Printers
Rather than providing a printer for each computer, we recommend that organizations purchase a single, network-enabled laser printer (or more than one for large offices). A single printer simplifies maintenance, supply purchasing (toner or ink), and management. Laser printers, though more expensive to purchase than inkjet printers, are much cheaper to operate on a per-page basis (about half the cost of inkjet) and so have a much lower total cost of ownership. Laser printers are also more robust and provide higher quality text output.
We strongly recommend purchasing computers with integrated Ethernet controllers and print servers, such as the HP 4250n. The integration between the printer and the network interface improves reliability and performance over stand-alone print server devices.
Some organizations may require color printing, in which case we recommend a basic inkjet printer. Be aware of the high cost of ink and special treated paper. Some organizations with privacy concerns may need to purchase printers for individual staff, in which case low-cost inkjet printers may be appropriate. Whenever possible, purchase printers that use the same consumables (ink cartridges and print heads), as this can allow for reduced purchasing and support costs.