Routers

Router is a device that connects two different networks. It translates one network IP address to a different network IP address. It translates public IP address to private and vise verse, translates private IP address to private and public to public. Thus it plays a vital part in sharing internet connection. It can translate a single public IP address to a pool of private IP addresses and vice verse. Routers do have a DHCP server, NAT translator and inbuilt firewall. It can also be used as a switch and can do what a switch or a hub cannot. Hence it is termed as intellectual device. There are two types of routers based on their connectivity, wired and wireless. There are different types of routers based on their range of usage, and works in different modes such as NAT mode, bridge mode, etc. They also work as an access point and a range extender in wireless networks. Basic function of router is to route the packets to the appropriate client or server in a network.

Modem

The basic devices needed to establish an internet are computer and modem. What does a modem do?
To connect to the internet the computer should have an Ip address, to communicate with a server or a network the system sends a request and the server on the internet acknowledges and establishes the connection or communication. The computer understands only digital signals but the signals transmitted are of analog. Thus to translate digital signals to analog a device is needed. Similarly the computer communicates in digital codes, in order to send or transmit those signals as analog signals a device is used. Modem[modulator and demodulator] does both modulation and demodulation and it serves this purpose. There are different types of modem depending on the type of internet connection and functionality. Some examples are cable modem, DSL modem, NAT modem, Bridge modem, etc.