What is a Network Routers in Computer Network? Definition and Explanation

Network routers operate at the network layer (Layer 3) of the OSI (Open Systems Interconnection) model. Its primary function is to forward data packets between different computer networks, determining the optimal path for data transmission. Routers are crucial components in the functioning of the Internet and other large-scale networks. A router is a device that connects two or more packet-switched networks or subnetworks. It serves two primary functions: managing network traffic by forwarding data packets to their intended IP addresses and allowing multiple devices to use the same Internet connection.

Routers are networking devices operating at layer 3 or a network layer of the OSI model. They are responsible for receiving, analysing, and forwarding data packets from connected computer networks. When a data packet arrives, the router inspects the destination address, consults its routing tables to decide the optimal route and then transfers the packet along this route.

A virtual router is a software function or software-based framework that performs the same functions as a physical router. It may be used to increase the reliability of the network by virtual router redundancy protocol, which is done by configuring a virtual router as a default gateway. A virtual router runs on commodity servers, and it is packaged with alone or other network functions, like load balancing, firewall packet filtering, and wide area network optimization capabilities.

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Why routers?

A router is more capable as compared to other network devices, such as a hub, switch, etc., as these devices are only able to execute the basic functions of the network. For example, a hub is a basic networking device that is mainly used to forward data between connected devices, but it cannot analyze or change anything with the transfer of data. On the other hand, the router has the capability to analyze and modify the data while transferring it over a network, and it can send it to another network. For example, generally, routers allow sharing of a single network connection between multiple devices.

How does a network router work?

A router works by receiving, analyzing, and forwarding data packets between different computer networks. A router examines a packet header’s destination IP address and compares it against a routing table to determine the packet’s best next hop. Routing tables list directions for forwarding data to particular network destinations, sometimes in the context of other variables, like cost. They amount to an algorithmic set of rules that calculate the best way to transmit traffic toward any given IP address. A routing table often specifies a default route, which the router uses whenever it fails to find a better forwarding option for a given packet. For example, the typical home office router directs all outbound traffic along a single default route to its internet service provider (ISP).

Here’s a step-by-step explanation of how a router functions:

Packet Reception: When a data packet arrives at a router, it enters one of its interfaces (physical ports). The router examines the packet’s header to extract crucial information, including the source and destination IP addresses.
Routing Table Lookup: The router consults its routing table, which contains a list of known networks and the associated next-hop routers or interfaces. It searches for the best matching entry based on the destination IP address of the packet.
Path Determination: Using routing protocols like OSPF, RIP, or BGP, the router determines the optimal path for the packet to reach its destination. It considers factors such as network congestion, link speed, and routing metrics to make this decision.
Forwarding Decision: Once the optimal path is determined, the router selects the appropriate next-hop router or interface to forward the packet. It modifies the packet’s destination MAC address to match that of the next-hop router or the outgoing interface.
Packet Forwarding: The router sends the packet to the selected next-hop router or out through the designated interface. It encapsulates the packet within the appropriate data link layer protocol (e.g., Ethernet) and transmits it over the physical medium.
Repeat the Process: The router repeats these steps for each incoming packet, making individual forwarding decisions based on the destination IP address and the information in its routing table. This process allows the router to handle multiple simultaneous data flows.

Additionally, routers perform other functions to ensure efficient and secure data transmission:

Network Segmentation: Routers enable the division of a network into smaller subnets, facilitating better management, performance, and security by controlling the flow of data between different segments.
Network Address Translation (NAT): Routers with NAT capabilities translate private IP addresses used within a local network into a single public IP address when communicating with external networks. This allows multiple devices to share a single public IP address.
Firewall Protection: Many routers incorporate firewall functionality, which filters incoming and outgoing network traffic based on predefined rules. Firewalls enhance network security by blocking unauthorized access and potentially malicious data.
Quality of Service (QoS) Controls: Routers can prioritize specific types of network traffic over others. QoS controls allow routers to allocate network resources based on defined policies, ensuring that critical applications or services receive sufficient bandwidth and low latency.

Routers play a crucial role in directing data traffic across networks, determining the optimal path for data packets, and enabling efficient and secure communication between devices and networks.

Types of routers

There are several types of routers designed to cater to different network environments and requirements. Here are some common types of routers:

Home Router

Home routers are typically used in residential settings or small offices. They connect multiple devices to the Internet using technologies like Ethernet, Wi-Fi, or DSL. Home routers often include basic firewall capabilities and Network Address Translation (NAT) to allow multiple devices to share a single public IP address.

Wireless Router

Wireless routers combine the functionality of a traditional router with wireless access points. They allow devices to connect to the network wirelessly via Wi-Fi. Wireless routers are commonly used in homes, offices, and public spaces to provide wireless connectivity.

Enterprise Router

Enterprise routers are designed for larger networks, such as corporate environments. They offer more advanced features and higher performance capabilities than home routers. Enterprise routers often support multiple WAN connections, Virtual Private Networks (VPNs), Quality of Service (QoS) controls, and advanced security features.

Core Router

Core routers are high-performance routers used in the core of large networks, including Internet Service Provider (ISP) networks. They handle the bulk of network traffic and facilitate the interconnection of multiple networks. Core routers are optimized for fast packet forwarding and scalability.

Edge Router

Edge routers are located at the edge of a network, where the network connects to external networks or the Internet. They handle the traffic entering or leaving the network and provide services like network address translation, firewall protection, and Virtual LAN (VLAN) support.

Service Provider Router

Service provider routers are specifically designed for the needs of telecommunications service providers and ISPs. These routers are highly scalable and capable of handling large volumes of traffic in complex network architectures. They often incorporate advanced features like traffic engineering, Multiprotocol Label Switching (MPLS), and support for various routing protocols.

Virtual Router

A virtual router is a software-based router that runs on a virtual machine or a container in a virtualized or cloud environment. Virtual routers offer flexibility, scalability, and cost-effectiveness by eliminating the need for physical hardware.

Branch Router

Branch routers are used in branch offices or remote locations of an organization. They provide connectivity to the main network and often include features like VPN support, security services, and remote management capabilities.

These are some of the common types of routers, each serving specific network requirements based on the scale, purpose, and location of the network they are deployed in.

Features of router

A router works on the 3rd layer (Network Layer) of the OSI model, and it is able to communicate with its adjacent devices with the help of IP addresses and subnets.
A router provides high-speed internet connectivity with different types of ports like gigabit, fast-Ethernet, and STM link ports.
It allows the users to configure the port as per their requirements in the network.
Routers’ main components are the central processing unit (CPU), flash memory, RAM, Non-Volatile RAM, console, network, and interface card.
Routers are capable of routing the traffic in a large networking system by considering the sub-network as an intact network.
Routers filter out unwanted interference, as well as carry out the data encapsulation and decapsulation process.
Routers provide redundancy as it always works in master and slave mode.
It allows the users to connect several LANs and WANs.
Furthermore, a router creates various paths to forward the data.

Applications of routers

There are various areas where a router is used:

Routers are used to connect hardware equipment with remote location networks like BSC, MGW, IN, SGSN, and other servers.
It provides support for a fast rate of data transmission because it uses high STM links for connectivity; that’s why it is used in both wired and wireless communication.
Internet service providers widely use routers to send data from source to destination in the form of e-mail, a web page, image, voice, or a video file. Furthermore, it can send data all over the world with the help of an IP address of the destination.
Routers offer access restrictions. It can be configured in a way that allows for few users to access the overall data and allows others to access the few data only, which is defined for them.
Routers are also used by software testers for WAN communications. For example, the software manager of an organization is located in Agra, and its executive is located in a different place like Pune or Bangalore. Then the router provides the executive with the method to share his software tools and other applications with the manager with the help of routers by connecting their PCs to the router using WAN architecture.
In wireless networks, configuring VPN in routers can be used in the client-server model, which allows sharing of the internet, video, data, voice, and hardware resources.
In modern times, routers have the facility of inbuilt USB ports within the hardware. They have enough internal storage capacity. External storage devices can be used with routers to store and share data.

Routers are used to set up the operation and maintenance centre of an organization, which is known as the NOC centre. All equipment at a distant location is connected by routers on optical cable at a central location, which also offers redundancy through the main link and protection link topology.

Benefits of router

Routers offer numerous benefits in computer networking and communication. Here are some key advantages of using routers:

Security

Router provides the security, as LANs work in broadcast mode. The information is transmitted over the network and traverses the entire cable system. Although the data is available to each station, the station which is specifically addressed reads the data.

Performance enhancement

It enhances the performance within the individual network. For example, if a network has 14 workstations, and all generate approximately the same volume of traffic. The traffic of 14 workstations runs through the same cable in a single network. But if the network is divided into two sub-networks each with 7 workstations, then the load of traffic is reduced to half. As each of the networks has its own servers and hard disk, so fewer PCs will need the network cabling system.

Reliability

Routers provide reliability. If one network gets down when the server has stopped, or there is a defect in the cable, then the router services, and other networks will not be affected. The routers separate the affected network, whereas the unaffected networks remain connected, without interrupting the work and any data loss.

Networking Range

In networking, a cable is used to connect the devices, but its length cannot exceed 1000 meters. A router can overcome this limitation by performing the function of a repeater (Regenerating the signals). The physical range can be as per the requirement of a particular installation, as long as a router is installed before the maximum cable range exceeds.

Efficient Data Routing

Routers analyze data packets and determine the most optimal path for forwarding them to their destination. By efficiently directing traffic, routers help minimize network congestion, reduce latency, and improve overall network performance.

Network Segmentation

Routers enable network segmentation by dividing a large network into smaller subnets. This segmentation enhances network management, allows for better control of network resources, improves security by isolating traffic, and facilitates easier troubleshooting.

Interconnectivity

Routers connect multiple networks together, facilitating seamless communication between different networks. They enable devices on separate networks to exchange data, share resources, and access services across various network boundaries.

Scalability

Routers are highly scalable and can accommodate the growth of networks. As new devices are added or networks expand, routers can efficiently handle increased traffic and adapt to changing network requirements.

Network Address Translation (NAT)

NAT functionality in routers allows multiple devices within a private network to share a single public IP address. This conserves IP addresses, provides an extra layer of privacy, and adds a level of protection against unauthorized access.

Quality of Service (QoS)

Routers support Quality of Service controls, allowing network administrators to prioritize certain types of traffic. This ensures that critical applications, such as voice or video communication, receive sufficient bandwidth and low latency, enhancing the user experience.

Redundancy and Failover

Routers can be configured with redundant connections to provide network redundancy and failover capabilities. In case of a link or network failure, routers can automatically switch to an alternative path, ensuring uninterrupted network connectivity.

Wide Area Network (WAN) Connectivity

Routers are essential for connecting LANs (Local Area Networks) to WANs, such as the Internet or other remote networks. They provide the necessary protocols and technologies to establish and manage WAN connections, enabling access to external resources and services.

Flexibility and Adaptability

Routers support various routing protocols, allowing them to adapt to different network environments and accommodate diverse network configurations. This flexibility makes routers suitable for a wide range of network setups and requirements.

These benefits highlight the crucial role that routers play in network infrastructure, enabling efficient and secure data transmission, interconnectivity, and network management.

Routing protocols

Routing protocols are a set of rules and algorithms used by routers to exchange routing information, determine optimal paths, and make forwarding decisions for data packets. These protocols enable routers to dynamically adapt to changes in network topology and ensure efficient data transmission. Here are some common routing protocols:

Interior Gateway Protocols (IGPs):
- Routing Information Protocol (RIP): RIP is a distance-vector protocol that uses hop count as its metric to determine the best path. It is commonly used in small to medium-sized networks.
- Open Shortest Path First (OSPF): OSPF is a link-state protocol that calculates the shortest path using metrics like bandwidth and link cost. It is widely used in large networks due to its scalability, fast convergence, and support for hierarchical routing.
Border Gateway Protocol (BGP):
- BGP is an exterior gateway protocol used for routing between different autonomous systems (AS) in the internet. BGP focuses on exchanging routing information and making policy-based routing decisions.
Enhanced Interior Gateway Routing Protocol (EIGRP):
- EIGRP is a Cisco proprietary protocol that combines distance-vector and link-state characteristics. It supports fast convergence, automatic route summarization, and features like load balancing and unequal-cost load balancing.
Intermediate System to Intermediate System (IS-IS):
- IS-IS is a link-state protocol similar to OSPF and is often used in larger networks. It is commonly used in Service Provider networks and some large enterprise networks.
Routing Information Protocol Next Generation (RIPng):
- RIPng is the IPv6 version of RIP, designed for routing in IPv6 networks. It operates similarly to RIP but supports the larger address space and other IPv6 features.
Interior Gateway Routing Protocol (IGRP):
- IGRP is an older Cisco proprietary protocol, now mostly obsolete. It was used for routing within a single autonomous system and offered features like load balancing and route summarization.

These are just a few examples of routing protocols, each with its own features, characteristics, and use cases. The choice of routing protocol depends on factors such as network size, scalability requirements, convergence speed, network policies, and compatibility with other devices in the network. Network administrators select the appropriate routing protocol based on their specific network needs.

What is the difference between a router and a modem?

Although some Internet service providers (ISPs) may combine a router and a modem within a single device, they are not the same. Each plays a different but equally important role in connecting networks to each other and to the Internet.

A router forms networks and manages the flow of data within and between those networks, while a modem connects those networks to the Internet. Modems forge a connection to the Internet by converting signals from an ISP into a digital signal that can be interpreted by any connected device. A single device may plug into a modem in order to connect to the Internet; alternately, a router can help distribute this signal to multiple devices within an established network, allowing all of them to connect to the Internet simultaneously.

Think of it like this: If Bob has a router, but no modem, he will be able to create a LAN and send data between the devices on that network. However, he will not be able to connect that network to the Internet. Alice, on the other hand, has a modem, but no router. She will be able to connect a single device to the Internet (for example, her work laptop), but cannot distribute that Internet connection to multiple devices (say, her laptop and her smartphone). Carol, meanwhile, has a router and a modem. Using both devices, she can form a LAN with her desktop computer, tablet, and smartphone and connect them all to the Internet at the same time.

How do routers help your business?

A common tool for modern network computing, routers connect employees to networks, both local and the Internet, where just about every essential business activity takes place. Without routers, we wouldn’t be able to use the Internet to collaborate, communicate, or gather information and learn. Routers can also provide security. Embedded firewalls and content filtering software provide additional protection from unwanted content and malicious websites without affecting your online experience. A router isn’t just for data transmission or Internet connections, though. Most routers allow you to connect hard drives and use them as file-sharing servers, or printers that can then be accessed by anyone on the network.

How to buy a router?

When buying a router, it’s important to consider several factors to ensure you select the right one for your needs. Here’s a step-by-step guide on how to buy a router:

Determine your Requirements

Assess your network requirements and understand what you need from a router. Consider factors such as the size of your network, the number of devices you need to connect, the desired network speed, coverage area, and any specific features or functionalities you require.

Research Router Types

Familiarize yourself with different types of routers available in the market, such as home routers, wireless routers, enterprise routers, or specialized routers based on your specific requirements. Understand their features, capabilities, and limitations to make an informed decision.

Internet Service Provider (ISP) Compatibility

Check with your ISP to ensure compatibility between the router you plan to buy and the internet connection you have or plan to get. Some ISPs have specific router requirements or compatibility lists.

Speed and Performance

Consider the router’s speed and performance capabilities. Look for routers that support the latest Wi-Fi standards (e.g., Wi-Fi 6 or 802.11ac) for faster and more reliable wireless connections. Consider the maximum data transfer rate (measured in Mbps or Gbps) the router can handle and ensure it meets your network’s speed requirements.

Coverage Area

Evaluate the coverage area of the router, especially if you need to provide wireless connectivity throughout your home or office. Look for routers with strong signal strength and multiple antennas to ensure sufficient coverage for your intended area.

Security Features

Pay attention to the router’s security features. Look for routers with built-in firewalls, VPN support, and encryption protocols (e.g., WPA2 or WPA3) to enhance network security and protect your data.

Wired and Wireless Connectivity

Determine the types of connections you require. Ensure the router has sufficient Ethernet ports for wired connections to devices like desktop computers or gaming consoles. If you need wireless connectivity, ensure the router supports the desired Wi-Fi standards and has the appropriate number of wireless antennas.

Additional Features

Consider any additional features or functionalities you may need, such as parental controls, guest network support, USB ports for file sharing or printer connectivity, Quality of Service (QoS) controls, or support for advanced networking protocols.

Price and Budget

Set a budget for your router purchase and compare prices from different brands and retailers. Consider the long-term value and features offered by the router within your budget range.

Read Reviews and Compare Models

Read reviews from reputable sources or consult online forums to gather information about the performance, reliability, and user experiences of specific router models you are considering. Compare different models based on your requirements and make a shortlist of potential options.

Purchase and Setup

Once you have selected a router, purchase it from a trusted retailer or online platform. Follow the manufacturer’s instructions for setting up the router, including connecting it to your internet modem, configuring the network settings, and securing the router with a strong password.

Remember to keep your router’s firmware up to date by periodically checking for firmware updates from the manufacturer’s website. Regularly review and adjust the router’s settings based on your network’s changing needs. By following these steps, you can make an informed decision when purchasing a router that meets your network requirements, budget, and desired features.

Latest Network Routers?

Some popular router models that were popular as of my knowledge cutoff:

It’s important to note that router models and their specifications are continuously evolving, and new models may have been released since my knowledge cutoff. To get the most up-to-date information on the latest router models, I recommend visiting the websites of networking equipment manufacturers or consulting technology publications and forums that cover network infrastructure.

Network Routers Providing Companies?

There are several companies that specialize in manufacturing network routers. Here are some notable companies known for their networking equipment, including routers:

These are just a few examples of companies known for producing network routers. Each company offers a variety of router models with different features, performance levels, and target markets. It’s important to research and compare specific router models and their specifications to find the best fit for your network requirements.

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