Internal Components of Router

A Router is a networking device that fulfills the need for devices to share files and forward data packets between devices over computer networks. Routers perform some directing functions on the Internet so the data sent over the internet, such as a web page in the form of data packets

Example: Let us understand this by a very general example, suppose, we search for www.google.com in your web browser then this will be a request which will be sent from system to the google`s server to serve that webpage, now the request is nothing but a stream of packets don`t just go the google`s server straightaway they go through a series of devices known as a router which accepts this packets and forwards them to correct path and hence it reaches to the destination server. 

How does Router work?

A wireless router connects directly to a modem by a cable then a router can receive and transmit information or data to the internet. Then the router starts to communicate with the wifi network and provides internet access to all devices within the network range of the router.

A generic router consists of the following components: 

1. Input Port: This is the interface by which packets are admitted into the router, it performs several key functions as terminating the physical link at the router
2. Switching Fabric: This is the main component of the Router, it connects the input ports with the output ports. It is kind of a network inside a networking device.
3. Output Ports: This is the segment from which packets are transmitted out of the router. The output port looks at its queuing buffers (when more than one packets have to be transmitted through the same output port queuing buffers are formed) and takes packets
4. Routing Processor: It executes the routing protocols, and works like a traditional CPU. It uses various routing algorithms like link-state algorithm, distance-vector algorithm, etc.

The Internal Components of Router:

Below is the raw diagram showing the internal components of the router:

Internal Components of Router

The router is an intelligent device, routers use routing algorithms such as Dijkstra’s Algorithm to map the destination or to find the best route to a destination on the parameters like the number of hops.

1. CPU: The CPU in the router executes the commands and processes the commands in the operating system. The flow of data on the interface is controlled by the CPU.
2. ROM: Read Only Memory in the router mainly works when the router boots up or is powered up. It stores the bootstrap program needed when the router is turned on.
3. RAM: Random Access Memory in the router contains the executable file and running file of the configuration file and the contents are lost when the router’s power is turned off.
4. Flash Memory: It contains the operating system. The data of the flash memory remain unchanged when the router is rebooted or powered off. So, whenever the router is powered on the OS is loaded into RAM from flash memory.
5. NVRAM: It stands for Nonvolatile RAM. It is a backup copy of the running configuration file. Its functioning basically helps when the router loses power and the router needs to establish the configuration and load it again. The content of NVRAM is changeable. When the router is powered on it searches the startup-config file in NVRAM only.
6. Interfaces / Ports: If we want to connect the router with wire or we want a wired connection there are multiple interfaces that are used to connect the network. i.e. Fast Ethernet, Gigabit Ethernet, and Serial.