LAN stands for Local Area Network. It is a type of computer network that covers a small area. In LAN, the nodes are connected via cables. A LAN may use the star topology, ring topology or bus topology. The network of computers in computer laboratory of a college and network of computers in an office building are examples of LANs.

Components of LAN
Different components that can be used in LAN are described below.

Communication Media
Network-Interface Card (NIC)
Router
Gateway
Bridge

1- Communication Media
In a LAN, computers (or nodes) are connected together through communication media. Some LANs use twisted wire pairs. Many LANs use coaxial cable or fiber optical cable. These cables are more expensive, but faster than twisted wire pairs. Some LANs use wireless transmission media instead of cables. Wireless networks are easy to use to set up and configure. Wireless networks are slower than cable networks.

2- Network-Interface Card (NIC)
    A network interface card (NIC) is used to connect a computer to local area network. Its is a circuit board. It is installed in expansion slot on motherboard. The NIC has a socket where the network cable is connected. The most popular network interface card is Ethernet card. It is also called LAN card.

3- Router
    Router is an electronic device. It used to connect two or more different or similar networks. It stores the addressing or routing information of each computer on the connected networks.

When a router receives a packet of data, it looks the address where the packet of data is to be sent. Router uses the routing information to transfer data along the most efficient path.

4- Gateway
    A gateway is an electronic device. It used to connect two or more different types of networks. It translates data from one format to the other.

Different networks may have different types of data and of different formats. Gateway receives data packet from one type of network. It reads the address of computer on the networks where data packet is to be sent. It converts the data packet into a format that the destination computer can understand.

5- Bridge
    A bridge is an electronic device. It is used to connect two similar network segments. It also controls the data flow between them. When a bridge receives a message, it reads address of both the the sender and receiver. If the sender and the receiver are the same network segment, the bridge does not pass the message to the other network segment. The message is directly sent to receiver. The bridge, therefore, reduces the network traffic. So the performance of network is increased.

5 Different Components of LAN (Local Area Network)