Networking 101 for Dummies
From DD-WRT Wiki
- DHCP server: A DHCP server provides IP settings (ip address, mask, gateway...) to devices on the LAN/VLAN, that are setup to receive an IP settings automatically. You can only have ONE DHCP server on each LAN/VLAN.
- GATEWAY: A GATEWAY is a router that connects the devices on a subnet to the internet. You should only have one Gateway on any subnet.
- Internet service provider (ISP, also called Internet access provider, or IAP): is a company that offers its customers access to the Internet. The ISP connects to its customers using a data transmission technology appropriate for delivering Internet Protocol datagrams, such as dial-up, DSL, cable modem, wireless or dedicated high-speed interconnects. ISPs may provide Internet e-mail accounts to users which allow them to communicate with one another by sending and receiving electronic messages through their ISP's servers. (As part of their e-mail service, ISPs usually offer the user an e-mail client software package, developed either internally or through an outside contract arrangement.) ISPs may provide other services such as remotely storing data files on behalf of their customers, as well as other services unique to each particular ISP.
- IP ADDRESS: An IP ADDRESS is a number from 0 to 2^32-1. To ease human readability it is mostly presented as four groups of numbers 0-255 separated by a "." - also called dotted decimal notation. Every device on a network has to have its own IP address. Here is an example of an IP address: 192.168.7.22.
- Local area network (LAN): is a computer network covering a small physical area, like a home, office, or small group of buildings, such as a school, or an airport. The defining characteristics of LANs, in contrast to wide-area networks (WANs), include their usually higher data-transfer rates, smaller geographic place, and lack of a need for leased telecommunication lines.
- SUBNET: A SUBNET (short for subnetwork) is a group of IP addresses that share 0 to 31 (typically 24) prefix numbers. Devices on different subnets cannot communicate with each other unless the subnets have routes to one another. Normally you set up different subnets so that the devices on one cannot communicate with the devices on another. Example 1: e.g. 24 leading ones mask of 255.255.255.0 net 192.168.1.0). Two devices, where one has the IP address of 192.168.1.5 and the other has the IP address of 192.168.1.6, are on the same subnet. If one had an IP address of 192.168.2.6, it would be on a different subnet. Example 2: e.g. 29 leading ones mask of 255.255.255.248 net 192.168.5.16). Two devices, where one has the IP address of 192.168.1.17 and the other has the IP address of 192.168.1.22, are on the same subnet. If one had an IP address of 192.168.1.25, it would be on a different subnet.
- Wide Area Network (WAN): is a computer network that covers a broad area (i.e., any network whose communications links cross metropolitan, regional, or national boundaries). The largest and most well-known example of a WAN is the Internet. WANs are used to connect LANs and other types of networks together, so that users and computers in one location can communicate with users and computers in other locations. Many WANs are built for one particular organization and are private. Others, built by Internet service providers, provide connections from an organization's LAN to the Internet. WANs are often built using leased lines. At each end of the leased line, a router connects to the LAN on one side and a hub within the WAN on the other. Leased lines can be very expensive. Instead of using leased lines, WANs can also be built using less costly circuit switching or packet switching methods. Network protocols including TCP/IP deliver transport and addressing functions.
- Wireless access point (WAP): is a device that allows wireless communication devices to connect to a wireless network using Wi-Fi, Bluetooth or related standards. The WAP usually connects to a wired network, and can relay data between the wireless devices (such as computers or printers) and wired devices on the network.
- Wireless Internet Service Providers (WISPs): are Internet service providers with networks built around wireless networking. The technology used ranges from commonplace Wi-Fi mesh networking or proprietary equipment designed to operate over open 900MHz, 2.4GHz, 4.9, 5.2, 5.4, and 5.8GHz bands or licensed frequencies in the UHF or MMDS bands.
- Wireless LAN (WLAN): is a wireless local area network that links two or more computers or devices using spread-spectrum or OFDM modulation technology based to enable communication between devices in a limited area. This gives users the mobility to move around within a broad coverage area and still be connected to the network. For the home user, wireless has become popular due to ease of installation, and location freedom with the gaining popularity of laptops. Public businesses such as coffee shops or malls have begun to offer wireless access to their customers; some are even provided as a free service.