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LAN
A
LAN
is a computer network that connects a relatively small area (a single building or group of
buildings). Most LANs connect workstations and computers to each other. Each computer (also
known as a “node”), has its own processing unit and executes its own programs; however, it can also
access data and devices anywhere on the LAN. This means that many users can access and share
the same information and devices. A good example of a LAN device is a network printer. Most
companies cannot afford the budgetary or hardware expense of providing printers for each of its
users. Therefore, one printer (i.e., device) is placed on the LAN where every user can access the
same printer.
The LAN uses IP addresses to route data to different destinations on the network. An IP Address is a
32-bit numeric address written as four numbers separated by periods (For example, 1.160.10.240.
Port
A
port
, when referring to TCP and UDP networks, is an endpoint in a logical connection. The port
number identifies the type of port it is. For example, port 80 is used for HTTP traffic.
Routers
A
router
is a device that forward data packets over networks. Most commonly, a router is connected
to at least two networks (normally LANs or WANs). Routers are located at gateways, the place where
two networks are connected. Routers do little data filtering, they mainly deliver the data.
Subnet
A
subnet
is a portion of a network that shares a common address component. On a TCP/IP network,
a subnet is described as all computers or devices whose IP Address have the same prefix.
Subnetting a network is useful because it provides security for the network as well as increases
performance of the network. IP networks are divided using subnet masks.
Switches
A
switch
is a device that filters and forwards data packets between networks. Switches operate at the
data layer, and sometimes at the network layer.
WAN
A
wide area network
connects two or more LANs and can span a relatively large geographical area.
For example, Telex Headquarters in Burnsville, MN is connected to several of its branch offices in
Nebraska and Arkansas over the wide area network. The largest WAN in existence is the Internet.
