Types of Network Hardware Devices and Their Functions

Network devices are the hardware components of computer networks that facilitate communication and data transfer within a network. Some of the network devices you must have heard of are- router, switches, hubs, etc.

In this article, we will go in-depth to understand the network devices in networking, their types, and functions. We will learn how these networking devices connect to form the computer network we use today.

For aspiring network engineers or CCNA enthusiasts, we have also added the configuration techniques of some devices for Cisco technologies. Derived from our IT infrastructure courses, this article provides expert knowledge in simple language.

What is a Network Device?

A Network device is a physical component that connects different computers or other devices to a network, maintaining the communication within a computer network.

These devices are responsible for managing network traffic and enhancing the connectivity, performance, and security of a network. They enable seamless collaboration among internet-compatible devices, such as computers, printers, and servers.

Why Do We Need Network Devices?

The computer networks we rely on every day, whether at home, in offices, or across the internet, are built, maintained, and operated using network devices. These hardware components form the backbone of any network infrastructure, and without them, creating or managing a network would be impossible. Network devices are essential for several reasons:

● Devices like routers and switches allow multiple systems to connect and communicate within local and global networks.

● Network devices control the flow of data, ensuring it reaches the correct destination without congestion or loss.

● Firewalls and security appliances protect networks from unauthorized access, malware, and cyber threats.

● Devices like hubs and access points help expand infrastructure without compromising performance.

● Network devices maintain stable connections and reduce downtime, which is critical for businesses.

What is the Role of Network Devices in Computer Networks?

Different network devices have different functions in a computer network. The basic functions of a networking hardware device include:

● Transmit and receive data between connected devices to facilitate communication.

● Ensure efficient connectivity by linking different hardware components within a network.

● Enhance security by controlling access and preventing unauthorized connections.

● Allow network segmentation, helping to isolate traffic and improve overall security.

● Manage data flow, optimizing network speed and performance.

Common Network Hardware Devices

Here is a list of some computer networking devices that are the most important components of networking:

If you learn more about network hardware devices and their use in the real world, enroll in our instructor-led live CCNA training. Feel free to contact our learning advisor for any further details.

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Types of Network Devices and Their Functions

Now, let's look at different types of network devices and understand the function of each device in a computer network.

1. Router

Routers are the core component of the networking devices that you see in the organization's data centers, branch offices, or small home office networks. The router in the computer network operates on the network layer, which is Layer 3 of the OSI model.

The primary role of a router is to connect two or more different networks, which facilitates the exchange of data packets between the networks. The network router can make decisions based on the destination IP addresses present in the received packets.

It determines the most appropriate outgoing interface based on the existing routing table for forwarding those packets to the next router in the network. These routing tables are formed with the help of static routes or routing protocols like OSPF, EIGRP, BGP, etc.

Function of Router

We will understand the functionality of the router based on the scenario below. Understanding IP addressing is essential before proceeding, as these are the critical elements of network building blocks.

In a corporate or small home office network, a router typically connects to an internal network known as the local area network (LAN) and to the Internet or WAN. When a device on the LAN sends a data packet, the router receives it and checks the destination IP address.

Using its routing table, which is often built from a default route, the router determines the best interface to forward the packet to reach the Internet. When return packets arrive, the router forwards them to the original device that sent the request. This process ensures efficient data communication within and outside the network.

Here is the Cisco network router configuration:

In this example, the router in the computer network has two interfaces. The router network interface GigabitEthernet0/0 is connected to the LAN with the IP address 192.168.1.1, and the network interface GigabitEthernet0/1 is connected to another network called the Internet with the IP address 10.0.0.1.

The "ip route" command sets the default gateway for the network router, specifying that any traffic with unknown destinations should be forwarded to the IP address 10.0.0.254. Sometimes this refers to a gateway in a computer network or just a gateway network.

2. Switches

Switches are devices that connect multiple devices, such as computers and printers, within a local area network (LAN). They manage data traffic efficiently by directing data only to the devices that need it, enhancing overall network performance.

Switches primarily operate at the data link layer (Layer 2) of the OSI model, making forwarding decisions based on MAC addresses. They maintain MAC address tables to identify which devices are connected to which ports, allowing them to efficiently forward Ethernet frames only to the intended recipients. This process enhances network performance by reducing collisions and creating separate collision domains.

Layer 2 switches are essential for local network segmentation, but cannot manage traffic between different VLANs. In contrast, Layer 3 switches have routing capabilities, allowing them to forward packets based on both MAC and IP addresses, enabling communication between different VLANs and subnets.

Types of Switches

Different types of switches in computer networks are:

1. Unmanaged Switch.

2. Managed Switch.

3. Smart Switch.

4. Layer 2 Switch.

5. Layer 3 Switch.

6. PoE Switch (Power over Ethernet).

7. Gigabit Switch.

8. Rack-Mounted Switch.

9. Desktop Switch.

10. Modular Switch.

Here are some of the Cisco switch models.

Functions of Switch

In an office network, a Layer 2 switch connects multiple computers and devices within a local area network (LAN). When a device sends data to another device on the same LAN, the switch checks the MAC addresses in the data packets and forwards them to the correct port.

Devices within the same VLAN can communicate directly, while those in different VLANs need their respective gateway IP addresses configured on a Layer 3 switch or router to communicate. This setup allows for efficient data transfer and network management.

Here is the configuration of a Layer 2 switch.

In this example, the switch has two ports configured as access ports. Port FastEthernet0/1 is assigned to VLAN 10 (Sales), and port FastEthernet0/2 is assigned to VLAN 20 (Marketing). The "vlan" command is used to create the VLANs and assign names to them.

Layer 3 switches in computer networks, also known as multilayer switches, combine the features of Layer 2 switches with routing capabilities found in routers. They can perform routing functions at wire speed and facilitate inter-VLAN communication by routing traffic between different VLANs.

A this point, you may be wondering if we already have routers that work at layer 3, what these layer 3 switches do, and what the differences arebetween a router and a switch.

Sometimes in a network, it is required to have multiple VLANs for various reasons. In that case, a Layer 3 switch can be configured as a default gateway for these VLANs. These VLANs can then route traffic between each other on the switch. It examines the IP addresses in packets and forwards them based on the routing table entries.

Here is the configuration of a Layer 3 switch.

In this example, the switch has a trunk port (GigabitEthernet0/1) to carry VLAN traffic. Two VLAN interfaces (Vlan10 and Vlan20) are configured with IP addresses. The "ip routing" command enables routing functionality on the Layer 3 switch. These IP addresses are the gateways on the devices in their respective VLANs,

The above-mentioned switches are Cisco Catalyst switches, and mostly you can use them as access switches in live production environments where users are directly connected. You can learn about these switches with some basic training and hands-on exercises.

There are several other types of switches used and offered by Cisco from their data center product portfolio.

There are heavy-duty data center Cisco Nexus switches, you can use these switches where they can handle a high volume of network traffic, and scalability is not a challenge. These Nexus switches also come up with fully functional automation through software-defined networks, using Cisco ACI switches used in plug-and-play environments.

Once you are comfortable with Cisco access switches, you can go ahead and start learning Cisco Nexus and ACI switches either through self-paced videos or via instructor-led live training. Learning these skills will keep you on top and will give you many more opportunities shortly.

3. Firewalls

Firewalls are crucial network security devices that monitor and control incoming and outgoing traffic based on predefined security rules. They can be hardware, software, or cloud-based, functioning as barriers between trusted internal networks and untrusted external ones, such as the Internet.

Firewalls filter traffic to allow safe data while blocking potentially harmful connections, thus protecting networks from unauthorized access and cyber threats.

Types of Firewalls

Different types of firewalls in networking are:

1. Packet Filtering Firewalls

2. Stateful Inspection Firewalls

3. Proxy Firewalls

4. Next-Generation Firewalls (NGFW)

5. Cloud Firewalls

Cisco Firepower is a cutting-edge security solution for protecting networks from advanced threats and attacks. It is a relatively new device, so there is not much training available on the internet for free. However, organizations are deploying on a large scale. Live training on Cisco Firepower will equip professional candidates to manage, operate, and implement such security solutions.

The picture below is the Cisco Firepower 1000 series appliances, which are considered NGFW.

NGFWs combine traditional firewall features (such as stateful packet inspection) with advanced capabilities such as application-layer filtering, user identity awareness, and threat intelligence.

They inspect network traffic at multiple layers, including application, transport, and network layers, to enforce security policies and prevent unauthorized access. Below are a couple of scenarios where IPS or NGFW is used.

Scenario 1: In an enterprise network, an NGFW is deployed at the network perimeter to inspect incoming and outgoing traffic. It can block malicious websites, detect and prevent intrusions, and provide granular control over network applications and user access.

IPS systems monitor network traffic for suspicious patterns or known attack signatures. They analyze packets in real-time to identify and block malicious activities.

Scenario 2: In a data center environment, an IPS is deployed to monitor traffic between servers. It can detect and prevent attacks like DDoS, SQL injection, and buffer overflow by inspecting the content of network packets.

Here's a simplified example of configuring access control policies on a Cisco NGFW (ASA):

In this example, an access control list (ACL) is created to permit web traffic (TCP ports 80 and 443). Another ACL denies all IP traffic.

A class map is defined to match the web traffic ACL, and a policy map is created to inspect HTTP and HTTPS traffic. The policy is then applied to the outside interface, and the access-group command applies the blocking ACL to the outside interface.

4. Access Points

Wireless Access Points (WAPs) are the wireless network hardware devices that are used to send Wi-Fi signals to provide wireless connectivity to wireless devices in a specified area. They act as a bridge between wireless devices and the wired network infrastructure.

They play a crucial role in creating and expanding wireless local area networks (WLANs), allowing devices like laptops and smartphones to connect to the internet and network resources. APs are strategically placed in areas such as offices to ensure reliable Wi-Fi coverage.

The picture below shows the Cisco Wireless Aironet 3600 series access points.

The access point handles the transmission of data packets between wireless devices and other network devices.

Types of WAP

Different types of WAP in networking are:

1. Indoor Access Points

2. Outdoor Access Points

3. Standalone Access Points

4. Controller-Based Access Points

5. Multifunction Access Points

6. Ceiling-Mounted Access Points

7. Wall-Mounted Access Points

8. PoE Access Points (Power over Ethernet)

9. Dual-Band Access Points

10. Mesh Access Points

Here's a simplified example of configuring a Cisco Aironet access point:

In this example, the WiFi network access point has a wireless interface (Dot11Radio0) configured with the SSID "ExampleNetwork." The network interface GigabitEthernet0 is configured as a trunk port to carry multiple VLANs. The BVI1 interface is configured with an IP address for management purposes.

5. Controllers (Cisco DNA Center and WLC)

Controllers are network management devices that provide centralized management and control of various network components in computer networks, such as access points and switches.

Cisco DNA Center is a software-based network hardware type controller that enables centralized management, automation, and assurance for enterprise networks. It provides a single dashboard for managing types of network devices, implementing policies, and monitoring network health.

The picture below is the dashboard of DNAC.

The computer network hardware devices, such as routers, switches, firewalls, access points, etc., are being managed and monitored by DNA Center. It is preferably used in a large enterprise environment where it is difficult to manage them manually.

With the help of DNA, network engineers can perform various functions such as upgrading IOS on devices from a centralized location, and can also troubleshoot network issues without logging into each device.

As Cisco DNA Center is a software-based controller, there is no specific configuration example. However, typical tasks performed through the Cisco DNA Center include:

● Adding computer network devices (routers, switches, access points) to the inventory.

● Creating network profiles for devices and applying standardized configurations.

● Defining policies for network access, security, and quality of service.

● Monitoring network health, performance, and security.

● Automating network operations and deploying software updates.

The Cisco Wireless LAN Controller is a specialized controller designed for managing wireless networks. You can also learn further about it from a video course.

It centralizes the configuration, security, and management of access points. The picture below is the Cisco Wireless LAN Controller 5500 series.

In a wireless network deployment, it's easy to configure and setup Cisco WLC, which is used to manage multiple access points. It handles tasks such as AP discovery, client authentication, and radio resource management to ensure efficient and secure wireless connectivity. The WLC training videos explain the full process of discovery and authentication with hands-on exercises starting with the initial setup.

6. Endpoints

Endpoints are also types of network hardware devices connected to the user ports of the switch in a computer network. These devices are the ones that send and receive the data for the end users. Such devices include laptops, desktops, cameras, phones, etc.

In a typical office network, endpoints can include employee workstations, laptops, and mobile devices. Applications run on these devices to perform tasks like sending emails, sharing files, browsing the internet, etc.

7. Network Servers

Servers are high-end computer network hardware devices that provide resources such as CPU, RAM, Hard disk for storage, etc., for executing various services on a network. They are designed to handle specific tasks and deliver resources efficiently.

There are 2 most popular, i.e., open source Linux servers and proprietary Windows servers. In Linux, there are several flavors like Ubuntu, Red Hat, Kali, etc., with their release versions, and similarly, in Windows, we have Windows 2010, 2012, 2016, etc.

Scenario: In an enterprise network, hardware types like servers play a crucial role in providing various services. These services include storage, computing, web hosting, email service, database, etc.

8. Power over Ethernet (PoE)

PoE is a technology that provides power and data to the end network components in computer networks over the same Ethernet cable.

With PoE, power-sourcing equipment (such as PoE switches) can deliver electrical power to PoE-enabled devices without the need for separate power cables.

The picture below is the Cisco Catalyst c2960x 48 port PoE switch. A normal twisted pair Ethernet cable is required to connect from switch ports to the end devices, such as an access point (access point does not require any other external power) to withdraw power.

In a network deployment, PoE is commonly used to power up the components of computer networks such as IP phones, wireless access points, and security cameras etc.

This eliminates the need for additional power outlets near these devices and simplifies cabling.

Here's an example configuration for a Cisco PoE switch:

In this example, GigabitEthernet0/1 is configured to automatically detect and provide power to a connected PoE device. GigabitEthernet0/2 is configured to deliver a static amount of power (15,000 milliwatts) to the connected device.

Challenges in Network Device Management

1. Device Configuration Errors

If a device is misconfigured, it can lead to network outages or security vulnerabilities.

Solution: Use automated configuration tools and templates to ensure consistency. Implement version control and regularly back up configurations.

2. Firmware and Software Updates

Old network devices with outdated firmware can expose devices to bugs and security threats.

Solution: Schedule regular updates and use centralized management systems to push patches across multiple devices efficiently.

3. Network Performance Monitoring

In a computer network, where multiple devices are connected, identifying bottlenecks or failures in real time can be difficult.

Solution: Deploy network monitoring tools (like Nagios, PRTG, or SolarWinds) to track performance metrics and receive alerts for anomalies.

4. Security Management

Network devices will always be targeted in cyberattacks.

Solution: Implement firewalls, access control lists (ACLs), and intrusion detection systems (IDS). Regularly audit device logs and enforce strong authentication.

5. Device Scalability

With an increasing network size and more devices added, managing them becomes complex.

Solution: Use scalable network management platforms and segment networks using VLANs or SDN (Software-Defined Networking) for better control.

6. Lack of Centralized Visibility

For a widespread computer network, managing devices across multiple locations can lead to blind spots.

Solution: Adopt centralized dashboards or cloud-based network management solutions to gain unified visibility and control over all devices.

How to Ensure Optimal Security of Network Devices?

In today’s hyper-connected world, network devices have become critical points of vulnerability for a computer network. From routers and switches to firewalls and access points, these devices form the backbone of digital infrastructure, but they’re also frequent targets for cyberattacks.

Misconfigurations, outdated firmware, and weak access controls can expose entire networks to threats like data breaches, malware, and unauthorized access. Ensuring the optimal security of network devices is essential to protect sensitive information, maintain uptime, and safeguard both personal and organizational assets.

Here are some best practices you should follow to keep your network devices secure from malicious actors.

1. Keep Firmware and Software Updated: Regularly update device firmware to patch vulnerabilities and improve security features. Enable automatic updates where possible.

2. Change Default Login Credentials: Always replace default usernames and passwords with strong, unique credentials to prevent unauthorized access.

3. Enable Firewalls and Access Controls: Use built-in firewalls and configure access control lists (ACLs) to restrict traffic and limit exposure to threats.

4. Break Your Network into Small Segments: Divide your network into zones (e.g., guest, internal, IoT) using VLANs to contain breaches and reduce risk.

5. Monitor Device Logs and Traffic: Use network monitoring tools to track unusual activity, failed login attempts, and traffic spikes that may indicate threats.

6. Disable Unused Services and Ports: Turn off unnecessary features and close unused ports to minimize attack surfaces.

7. Implement Encryption: Use protocols like WPA3 for wireless networks and ensure data in transit is encrypted using TLS or VPNs.

8. Regular Security Audits: Conduct periodic audits and vulnerability scans to identify and fix potential weaknesses.

Summing Up!

Network devices are essential components that facilitate communication and data transfer within a network. Key devices include routers, which direct traffic; switches, which connect devices within a network; and access points, which enable wireless connectivity.

Proper configuration of these networking devices ensures efficient network performance, security, and reliability, making them crucial for both small and large-scale networks. Understanding their functions and configurations is vital for effective network management and optimization.