Networking
This section is primarily focused on the small office or home office that does not use a "server". This is known as "peer to peer" networking where each computer is self-managed and simply shares resources as peers. Contrarily, a server-based network depends on a master computer (aka the 'server') to manage many things such as addressing and protection from threats.
In a peer to peer network, you most likely are sharing an internet connection - a cablemodem, dsl modem, or other high-speed, always-on connnection to the internet. While this web page is not intended to provide a comprehensive primer to networking, we'd like to make sure you know a few things about what is required. Your network needs a few devices to operate. The list below describes functions that networking hardware accomplish (some required, some optional). In the case of hardware for small offices and home offices, many commercially-available devices may do one or more of these functions:
- A modem provides the connection to the internet, translating from a phone, cable, or dsl type of connection to a standard ethernet type of connection. Data transmission is usually less than 56kb/sec for a telephone modem, up to 3mb/sec for a cable modem, and up to 1.5mb/sec for a dsl modem. Business services (such as T-1, OC-3, etc.) are much higher, but are beyond the scope of this discussion.
- Ethernet cabling runs provide the pathway for data from device to device throughout a local network. See below for a wireless alternative.
- A network adapter is usually what's installed in a network device (computer, printer, etc.) that has a port which accepts an ethernet cable jack. This adapter passes data from the cable to the device and back again.
- A hardware firewall is usually installed between the modem and the local network to ensure that only locally requested data traffic is passed from the internet to the local network devices and/or back to the internet. Firewalls use a few methods to do this, such as "rules", "filters", and Stateful Packet Inspection (SPI). The firewall's job is to protect your local network devices from data that hasn't been asked for. If your network didn't have such protection, someone could easily, for example, flood your network with unasked-for data that prevents your network from doing anything else (this is called a Denial of Service attack). Please see our Computer Security section for more information about this.
- A router takes care of device addressing and data traffic management. Every device that needs to communicate with another device needs to have a unique address. On the internet, the Internet Protocol (IP) addressing scheme is used, and everything connected to the internet needs a unique address (to prevent mis-directed data). In your local network, the router usually provides a single address to the internet, and uses Network Address Translation (NAT) to hide internal devices from the internet whilst managing data flow from one place to the other. Within your local network, the router assigns unique, private addresses to each device (computer, print server, etc.), and manages the data traffic to make sure each device gets the data intended for it.
- A switch or hub provides a physical way for many devices to communicate with each other. since ethernet cabling goes from one place to one other place, a switch or hub can allow multiple ethernet cables to all be hooked together. The switch or hub handles getting the data from one place to the other, according to the addressing structure mandated by the router.
- a wireless access point provides an alternative to ethernet cabling, in that it transmits data over radio frequencies instead of through wire. Currently there are 3 main standards in place, designated by codes:
- 802.11b is the oldest standard, operates at a frequency of 2.4 - 2.6ghz at a maximum of 11mb/sec, and is widely used nationwide. It allows for an encryption protocol, Wireless Encryption Protocol (WAP) that provides a small measure of protection against eavesdroppers. The usable range of this standard is about 1,500 feet in open air, 300 feet in a building. You can get better range with special antennas. This radio frequency spectrum is susceptible to interference from cordless telephones (the 2.4ghz variety), and microwave ovens, as well as other devices.
- 802.11g is a newer standard built on the 802.11b precursor. It operates at the same frequency spectrum, but at a much higher data transfer rate (54mb/sec and recently up to 108mb/sec). It can use a better type of encryption, Wi-Fi Protected Access (WPA) as well as WAP. It is susceptible to the same interference as 802.11b, but is backwards-compatible - 802.11g gear can work with 802.11b gear. This has quickly become the most popular standard due to this compatibility with existing equipment.
- 802.11a is another newer standard that hasn't become as popular as 802.11g, primarily because it uses a different frequency - 5ghz. Otherwise, it is similar to 802.11g in terms of data transfer rate and WPA. It is not compatible with the other standards noted above, because it uses different radio frequencies. It is also less susceptible to interference, primarily because there aren't a lot of 5ghz consumer electronics gear in use yet.
- In order for a device to communicate with a wireless access point, that device (a computer, a printer, etc.) must have an appropriate wireless network adapter that uses the same protocol. The wireless network adapter fulfills the same function as the network adapter noted above, passing data from the wireless network to the device and back out.
- (optional) a printer may have a print server device which accepts an ethernet cable (or has a wireless network adapter built-in) to transfer data from the network to the printer and vice versa. Many printers are directly connected to a computer, and that computer can provide 'print sharing' with other computers on the network. The print server takes over the function of managing print jobs, and any computer on the network can print without the help of another computer.
In a computer, Windows has software to handle the configuration of the network adapter. For ethernet cabled types, this is pretty straight-forward - just plug it in and it works. For wireless networks, it's more complicated. Depending on the brand of wireless network adapter installed, different software may do the job differently. Plus, Microsoft Windows XP has wireless networking built in, but watch out - it isn't very stable unless you have SP2 installed for Windows XP.
A note about addressing: The standard convention is the Internet Protocol (IP) and looks like a set of numbers, such as 192.168.0.1 or 207.69.188.185 (four sets of numbers of one to three digits). Each device (computer, modem, router, firewall, print server, etc.) is assigned a unique number so that data can be sent to the right place. On the internet, we have Domain Name Service (DNS) that allows more user-friendly addresses to be used, and a "DNS server" on the internet (supplied by your internet service provider) translates the name address (such as www.positek.net) to the correct IP address, enabling accurate routing of data from place to place.
If you'd like more indepth information about networking, we suggest you conduct a google search on various terms you see above.