What is a router in a network? Core functions explained

A router is a core element of internet connectivity. It is a device that allows multiple devices to connect to the internet and facilitates the forwarding of data packets to their respective destination addresses. Using dynamic routing technology, a router examines the data and selects the most efficient route for the information flow among the various available paths.

What exactly does a router do?

The main function of a router is to forward (or route) packets of data between networks. In networking, a packet is the basic unit of information transmitted across the Internet. Each packet contains a source IP address and a destination IP address. The job of a router is to efficiently route IP packets from the source station to the destination station without any hindrance.

Routers also have a variety of other functions, including:

Simplified management: Given the limited number of available IP addresses, routers use Network Address Translation (NAT) to allow multiple devices to share a single public IP address. NAT also improves network security and simplifies network management.

Packet filtering: Routers use filtering technology to monitor incoming and outgoing packets for suspicious traffic. They decide whether to allow or block packets based on filters such as port numbers, IP addresses, and Internet Control Message Protocol (ICMP) messages.

Dynamic routing: In dynamic routing, the router is able to adapt to changes in the network and choose the best path based on real-time conditions. If a router detects that part of the network is down, it consults its routing table and reroutes traffic to an alternate path.

Classify traffic: With the help of Quality of Service (QoS), routers prioritize which traffic will receive more favorable treatment.

How do routers work?

When a router receives a packet of data, it reads its IP header to understand where the data is going. First, it checks its routing table, which contains details of the paths to various network destinations. These routing tables use algorithms to help choose the best path to a destination.

The router then sends the data packet to the next node until it reaches the destination, thus achieving smooth data transmission.

Components of a Network Router

A network router consists of internal and external components. The internal components are:

CPU: The router's CPU can efficiently determine the best route for packets while keeping track of them.

Memory: Routers use different types of memory, such as RAM, read-only memory (ROM), flash memory, and nonvolatile RAM (NVRAM).

RAM: RAM is the main memory in your router, but it only stores data temporarily. If the router is turned off, all data is deleted.

Flash memory: Flash memory is a non-volatile memory designed to store the router's operating system. Even if the router is turned off, the contents stored in the flash memory will not be affected.

NVRAM: NVRAM is a type of non-volatile RAM that saves data even after the router is turned off.

Interfaces/Ports: Routers support multiple interfaces/ports (such as Ethernet and serial) to connect to various wires. In Ethernet, routers support Fast Ethernet and Gigabit Ethernet, while serial supports HDLC, PPP, and Frame Relay.

The external components of a router include:

WAN Port: The WAN port connects to a wide area network or the Internet.

LAN Port: The LAN port connects to the local area network and enables communication between connected devices.

Main types of routers

Routers used to be essentially the same: a piece of hardware that allows devices to communicate with each other over a network. But today, routers can take many different forms. Here are some of the most common:

Wired Router: The original type of router, a wired router uses physical Ethernet cables to share data across a network.

Wireless Router: A wireless router allows Wi-Fi internet connectivity through a built-in access point. These routers are widely used in homes and small offices and can support multiple devices simultaneously.

Edge routers: Edge routers are specialized wired or wireless routers located at the border of a network. These routers do not communicate with the internal network; instead, they communicate with external networks.

Virtual Router: A virtual router is a piece of software that allows a computer to function as efficiently as a physical router. It works similarly to a physical router by sharing packets and can scale quickly when needed. As such, it is an excellent choice for businesses looking for a high-performance networking solution.

Core Router: A core router is another form of specialized router that is used to forward data within the core of the network. This is ideal for large organizations and is designed to handle high traffic volumes.

What are the most common router problems?

There are many issues you can face with your router. Here are some common router issues and how to fix them:

Slow network

Slow networks are often encountered where multiple clients are trying to connect to a router that may or may not have enough capacity to accommodate all of them. In this case, the router may slow down the internet speed on one or more of the connected devices.

To fix a slow Internet connection, unplug your router, wait 30 seconds, and then plug it back in.

Weak signal

If your router is old or placed in an awkward location, it may block the Wi-Fi signal. In addition to this, physical interference such as large appliances or thick walls can also cause low signal strength.

To get a stronger Wi-Fi signal, remove any obstacles between the router and your wireless devices. Also, place the router on a high surface and keep it updated. In larger areas, you may need to use one or more Wi-Fi extenders.

locking

There are several ways to lock your router. Perhaps you've forgotten your password, or it may have been hacked.

Regardless of the reason, if you are locked out, you can reset your router password by pressing and holding the reset button.

Router Protocol

Routers use routing protocols to build routing tables, which contain detailed information about available paths to different networks. With this information, the router can determine the best route for each packet.

Types of Router Protocols

There are many types of router protocols. Here are some of the most common ones:

Routing Information Protocol (RIP)

RIP is one of the oldest routing protocols and is an interior gateway protocol that uses a distance vector algorithm to route packets to their destination. Distance vector routing determines the best path for a packet by simply calculating how many routers the packet must pass through (or "hop") to reach its destination.

However, RIP is not the best choice for large and complex networks. This is because it was designed to broadcast updates only once every 30 seconds - which was sufficient in the early days of networking, but cannot support modern network traffic, and only supports up to 15 hops.

The newer version of the protocol, RIPv2 (and its IPv6 extension RIPng), improves on RIP's shortcomings and provides additional features such as multicast, password authentication, variable-length subnet masks, poison reversal, etc., but is still limited to a maximum hop count of 15.

Open Shortest Path First (OSPF)

OSPF is a link-state routing protocol designed for TCP/IP environments. It uses the Dijkstra algorithm to calculate the best path for data packets to reach their destination.

Border Gateway Protocol (BGP)

BGP is a gateway protocol developed to replace EGP. Its main function is to transmit data packets between autonomous systems (AS) using the best path selection algorithm. Its outstanding features are support for next hop, Classless Inter-Domain Routing (CIDR), Transmission Control Protocol (TCP), and efficient network bandwidth utilization.

Instant System to Instant System (IS-IS)

IS-IS is a link-state classless protocol that uses Dijkstra's algorithm to find the best path for data transmission. It is used for routing in autonomous systems.

Summarize

A router is an essential component of modern network computing. Without it, most network connections would be impossible. A good router ensures fast, reliable, and secure data transfer on the network.

Network administrators should have a comprehensive understanding of routers, including their types and uses. This knowledge will help the organization choose which router to use and optimize network performance.