What is a router and what it does do in Computer Network?

We often hear the term “router” when talking about computer networks, but what exactly is a router? In this blog post, we’ll be discussing what is a router and what it does, as well as the different types of network equipment and devices, and how to connect them to a network.

What is a router? (DEFINITION)

A router is a networking device that basically forwards data packets between computer networks. Routers operate at the network layer (layer 3) of the OSI (Open Systems Interconnection) model, which is responsible for routing traffic between different networks.

Routers use routing tables to determine the best path for data packets to take, and they use protocols such as OSPF (Open Shortest Path First) and BGP (Border Gateway Protocol) to communicate with other routers and determine the best routes. Routers also typically include features such as network address translation (NAT) and firewall capabilities to help protect the networks they connect.

Routers are an essential component of most computer networks, as they allow different devices and networks to communicate with each other and access the internet.

Types of Network Equipment and Devices

In order to understand how routers work, it’s important to know the different types of network equipment and devices. There are a few types of devices that are commonly used in computer networks, and they can be broken down into three main categories:

Switches: Switches are devices that are used to connect two or more computers, servers, or other devices on a network. They are responsible for sending data packets between the connected devices, and can also be used to control which devices can access certain network resources.
Hubs: Hubs are devices that are used to connect multiple computers or devices together. They are responsible for receiving data packets from the connected devices and sending them to the appropriate destination.
Routers: As mentioned before, routers are responsible for sending data packets between computers, servers, and other devices on a network. They are also responsible for deciding which path to take when sending data, and they use a routing table to decide which device to send the data to.

How Router Works?

A router works by receiving data packets from a source device, examining the destination address of the packet, and then forwarding the packet to the next hop on its journey to the destination.

When a device on a network sends a data packet, it first goes to the router, which is typically connected to the device via a wired or wireless connection. The router examines the destination address of the packet and looks up the next hop in its routing table.

The routing table is a list of rules that the router uses to determine where to send incoming packets. It contains entries for each destination network, along with the next hop (usually another router) that the packet should be sent to in order to reach its destination.

Once the router has determined the next hop, it sends the packet out through one of its interfaces (ports) to the next hop. This process is repeated until the packet reaches its final destination.

Routers also perform other functions such as network address translation (NAT), which allows devices on a private network to access the internet using a single public IP address, and firewalling, which helps to protect the network from external threats by controlling incoming and outgoing traffic.

Here is a quick step of how a router works:

A device on a network sends a data packet to the router.
The router receives the packet and examines the destination address.
The router looks up the next hop in its routing table.
The router sends the packet out through one of its interfaces (ports) to the next hop.
The process is repeated until the packet reaches its final destination.
The router may also perform other functions such as network address translation (NAT) and firewalling.

Features Provided by Router

Here are some common features provided by routers:

Network Address Translation (NAT): NAT allows devices on a private network to access the internet using a single public IP address. This helps to conserve public IP addresses and increase security by hiding the internal network structure.
Firewall: A firewall helps to protect the network from external threats by controlling incoming and outgoing traffic based on predetermined security rules.
Quality of Service (QoS): QoS allows the router to prioritize certain types of traffic, such as real-time audio and video, over less time-sensitive traffic like file downloads. This can help to improve the performance of mission-critical applications.
Virtual Private Network (VPN) support: Some routers support VPNs, which allow users to securely access the network remotely over the internet.
Wireless Access Point (WAP): Many routers include a WAP, which allows devices to connect to the network wirelessly using Wi-Fi.
Port forwarding: Port forwarding allows the router to forward incoming traffic to a specific device on the network based on the destination port number. This is often used to allow external access to servers or other services running on the internal network.
Dynamic Host Configuration Protocol (DHCP) server: A DHCP server allows the router to automatically assign IP addresses to devices on the network. This simplifies network configuration and helps to prevent IP address conflicts.
Domain Name System (DNS) forwarding: A DNS forwarder on the router allows it to act as a local DNS server, caching DNS records and forwarding DNS queries to upstream servers as needed. This can help to improve the performance of DNS lookups on the network.
Access Control: Access control features allow the administrator to set up rules to allow or block certain devices or types of traffic from accessing the network.
Parental Controls: Parental controls allow the administrator to set up rules to limit access to inappropriate content or limit the amount of time that certain devices can access the internet.

Types of Router

There are several types of routers in computer networking, which are the following,

1. Residential router:

A residential router is a type of router that is designed for use in a home or small office environment. These routers typically have a built-in wireless access point (WAP) and provide features such as NAT, firewalling, and DHCP server capabilities.

2. Business router:

A business router is a type of router that is designed for use in small to medium-sized businesses. These routers often have more advanced features and greater scalability than residential routers, and they may support features such as VPNs, VLANs, and QoS.

3. Enterprise router:

An enterprise router is a type of router that is designed for use in a large organization. These routers are highly scalable and feature-rich, and they often support advanced networking protocols and technologies such as BGP and MPLS.

4. Wireless router:

A wireless router is a type of router that includes a built-in wireless access point (WAP). These routers allow devices to connect to the network wirelessly using Wi-Fi.

5. Virtual router:

A virtual router is a software-based router that runs on a virtual machine or in a cloud environment. Virtual routers are often used in virtualization environments or in cloud-based networks where it is not practical to use physical routers.

6. Edge router:

An edge router is a type of router that is located at the edge of a network and is responsible for connecting the network to external networks, such as the internet. Edge routers often have advanced security features to protect the network from external threats.

What is Routing Protocol?

A routing protocol is a set of rules and standards that are used by networking devices to exchange information about routes and reachability between network nodes. Routing protocols are used to build and maintain routing tables, which contain information about the topology of the network and the paths that data packets can take to reach their destination.

Types of Routing Protocols

There are several types of routing protocols that are used in computer networking:

1. Interior Gateway Protocols (IGPs):

IGPs are routing protocols that are used within a single autonomous system (AS), which is a network under a single administrative authority. Examples of IGPs include OSPF, IS-IS, and EIGRP.

2. Exterior Gateway Protocols (EGPs):

EGPs are routing protocols that are used to exchange routing information between autonomous systems. The most widely used EGP is the Border Gateway Protocol (BGP).

3. Distance-vector routing protocols:

Distance-vector routing protocols use a simple algorithm to determine the best path for a packet to take based on the distance (measured in hops) to the destination. Examples of distance-vector routing protocols include RIP and IGRP.

4. Link-state routing protocols:

Link-state routing protocols maintain a complete map of the entire network and use this information to determine the best path for a packet to take. Examples of link-state routing protocols include OSPF and IS-IS.

5. Hybrid routing protocols:

Hybrid routing protocols combine aspects of both distance-vector and link-state routing protocols. Examples of hybrid routing protocols include EIGRP and BGP.

6. Path-vector routing protocols:

Path-vector routing protocols maintain a list of the AS paths that a packet has taken and use this information to determine the best path to the destination. BGP is an example of a path-vector routing protocol.

Application of a Router

Connecting multiple devices to the internet: A router can be used to provide internet access to multiple devices on a home or office network.
Network segmentation: A router can be used to segment a network into separate subnetworks for security or performance reasons.
Load balancing: A router can be configured to balance the load across multiple internet connections to improve performance and reliability.
Traffic filtering: A router can be used to filter traffic based on various criteria, such as source or destination address, protocol, or port number.
VPN support: A router can be used to support VPN connections, allowing users to securely access the network remotely over the internet.
Wireless access point: A router can be used to provide wireless access to the network using Wi-Fi.
Firewall: A router can be configured as a firewall to control incoming and outgoing traffic and protect the network from external threats.
Quality of service: A router can be configured to prioritize certain types of traffic, such as real-time audio and video, to improve the performance of mission-critical applications.
Domain Name System (DNS) forwarding: A router can act as a local DNS server, caching DNS records and forwarding DNS queries to upstream servers as needed.
Network address translation (NAT): A router can be used to enable devices on a private network to access the internet using a single public IP address.
Connecting multiple networks: A router can be used to connect multiple networks together, allowing devices on different networks to communicate with each other.
Network storage: A router can be equipped with network-attached storage (NAS) capabilities, allowing users to access and share files over the network.
Virtual local area networks (VLANs): A router can be configured to create virtual local area networks (VLANs), allowing the administrator to segment the network into separate logical networks for security or performance reasons.
Wireless range extender: A router can be used to extend the range of a wireless network, allowing devices to connect to the network from farther away.

Differences between Hubs, Switches, and Routers

classification	Hub	Switch	Router
Function	Broadcast incoming data packets to all connected devices	Forward data packets to the specific device they are intended for	Forward data packets between different networks
Number of ports	Varies	Varies	Varies
Network layer:	Physical layer (layer 1)	Data link layer (layer 2)	Network layer (layer 3)
Address resolution	Does not resolve addresses or maintain a table of MAC addresses	Maintains a table of MAC addresses and uses this information to forward data packets	Uses routing tables and protocols such as OSPF and BGP to determine the best path for data packets
Performance	Lower than switches and routers	Higher than hubs, lower than routers	Higher than hubs and switches
VLAN support	No	Yes	Yes, often more advanced capabilities than switches
Cost	Lower than switches and routers	Higher than hubs, lower than routers	Higher than hubs and switches
Size	Generally larger than switches and routers	Varies, ranging from small desktop devices to larger rack-mounted units	Varies, ranging from small desktop devices to larger rack-mounted units
Power consumption	Higher than switches and routers	Lower than hubs, varies depending on the size and number of ports	Varies depending on the size and number of ports
Management features	Limited or no management features	Web-based or CLI interface for configuration and management	Web-based or CLI interface for configuration and management
Security	No security features	May have security features such as firewalling and access controls	May have advanced security features such as firewalling, intrusion detection and prevention, and access controls
Scalability	Low scalability	Moderate scalability	High scalability for enterprise-grade routers
Wiring	Uses twisted-pair cables for connections	Uses twisted	May use twisted-pair cables or fiber optic cables for connections
Suitable for	Smaller networks with minimal traffic	Larger networks or networks with multiple subnetworks	Larger networks or networks with multiple subnetworks

Conclusion

In this blog post, we discussed what is a router, what it does as well as the different types of network equipment and devices, how a router works and the types of routers. Routers are essential for the performance of a computer network, as they are responsible for sending data packets between computers, servers, and other devices on the network. They also can be used to connect different networks together, such as a home network to the internet.

Routers can be used in all types of networks, from small home networks to large corporate networks. In order to understand how routers work, it’s important to know the different types of network equipment and devices, such as switches, hubs, and routers. Once you have the necessary equipment and devices in place, the next step is to connect them to a network, which can be done in a few different ways depending on the type of network.

Routers are an essential part of any computer network, and understanding how they work is key to designing and maintaining an effective network. We hope this blog post has helped you gain a better understanding of what is a router and what it does in a computer network.