6.01.1 Compare and contrast common networking hardware Part 1

Introduction 

Imagine a postal system where every letter or package must find its way from sender to receiver. Now, imagine that instead of letters, we're talking about bits of data—tiny pieces of information that make up everything from emails to streaming videos. In the world of networking, these bits must be carefully directed to their destination, just like packages. In this lesson, we'll explore how networks manage the flow of information through different devices like hubs, switches, and routers, each playing a role in ensuring data gets where it needs to go.

By understanding these devices and how they function, you’ll be equipped to solve networking problems and help others maintain fast, reliable connections, whether in a small office or a large organization. 

Network Communications 

Network communications are carried out using bits, which are the smallest unit of digital information. Each bit can be either a 1 or a 0. To send data over a network, this digital information must be converted into a physical form that represents these 1's and 0's. 

To explain, it's similar to Morse code, where long and short beeps represent letters and words. In network communications, physical signals like electricity, light, or radio waves are used to represent binary data (1’s and 0’s). 

 For example, when electricity is used: 

  • A high voltage is interpreted as a 1. 

  • A low voltage is interpreted as a 0. 

This way, binary data can be physically transmitted between devices over a network. Depending on the medium (electric, optical, etc.), these 1’s and 0’s will be represented differently, but the concept remains the same. 

Network Interface Cards (NICs) 

A Network Interface Card (NIC) allows a computer to connect to a network, either using copper twisted pair cables or fiber optic cables. The NIC establishes communication through electrical signals (copper) or light pulses (fiber optic). Below are key details about NICs and how they work. 

Types of Connections

  • Copper Twisted Pair (Ethernet): Uses electrical signals to send data. 

  • Fiber Optic: Uses light pulses to transmit data over longer distances with less interference. 

Built-in and External NICs 

  • Built-in NICs: All modern computer motherboards come with a built-in 1000BASE-T adapter, which supports Gigabit Ethernet over copper cables.

  • External NICs: Additional NICs can be installed to support different Ethernet types, like fiber optic. You can also add NIC cards with multiple ports for more functionality.

Multiple Ports and Bonding 

  • Multi-Port NICs: NICs can come with two or four ports of the same type, such as 1000BASE-T. 

  • Port Bonding: Ports can be combined (bonded) to increase speed. For example, four Gigabit Ethernet ports can be bonded to create a connection with a 4 Gbps link speed.

External WiFi Network Interface Card

Data Link Protocol and Framing 

For the NIC to process the signals (whether electrical or light) as digital data, two things are needed: 

  • Framing: The data must be divided into regular units, called frames. 

    Addressing: Each computer (or node) on the network must be able to send and receive data using an address. 

Media Access Control (MAC) Address 

  • Every Ethernet NIC has a unique hardware address called a MAC address. 

  • The MAC address is used to identify both the sender and the receiver in every frame of data sent over the network. 

  • A MAC address is usually displayed as 12 hex digits, often with colons or hyphens for clarity, but it can also be written without any separators: Example: 00:60:8c:12:3a:bc or 00608c123abc. 

But where does data go after the NIC allows us to connect to the network? What’s the next step? 

Analogy: A MAC address is like a car’s license plate on a network.  Just like every car has a unique VIN or better yet, plate number to identify it on the road, every device has a unique MAC address, so the network knows who it’s talking to.  Even if two cars are the same model, their license plates are different—same with devices and their MAC addresses.  

Structure of a MAC Address 

  • A MAC address is 48 binary digits long (6 bytes). 

  • MAC addresses are written in hexadecimal (hex), which uses the digits 0-9 and letters A-F.  

Patch Panels 

In office cabling setups, computers are often connected to a wall port. This wall port is linked, through cables hidden in the walls, to a patch panel. Here’s how it works: 

Rear of the Patch Panel: Insulation Displacement Connector (IDC) Punchdown Blocks 

  • The cables running through the walls are terminated at the back of the patch panel using IDC punchdown blocks. 

  • Insulation Displacement Connectors (IDC) allow wires to be inserted without needing to strip insulation, making the connection process more efficient. 

Front of the Patch Panel: Prewired RJ45 Ports 

  • The front of the patch panel has prewired RJ45 ports, which are used for connecting network devices. 

  • To link a specific RJ45 port on the patch panel to a network switch, a patch cord is used. 

This design allows for flexibility in how wall ports are connected to the network, as you can easily adjust connections by plugging different patch cords into the appropriate switch ports. 

Patch Panel(rear)

Patch Panel(front)

Labeling System 

It is crucial to use a clear labeling system when installing this type of structured cabling. Proper labels ensure that you know which patch panel port corresponds to which wall port, making it easier to manage and troubleshoot the network. 

Hubs 

A hub is an older type of network hardware used to create 10BASE-T and 100BASE-T Ethernet networks. These networks are organized in a star topology, meaning that each device is connected to a central hub. 

How Hubs Work 

  • Ports: A hub typically has between 4 and 48 ports. Each computer or device is connected to one of these ports. 

  • Signal Repeating: When a computer sends data through the hub, the hub repeats the signal to all other ports, allowing all connected devices to receive the transmission. 

  • Collision Domain: All computers connected to the hub share the same network bandwidth. This setup is called a collision domain because multiple computers trying to send data at the same time can cause collisions. 

Collisions and Performance 

  • Ignoring Data: Each computer attached to a hub will receive all data sent by others but will only process data intended for its MAC address. 

  • Collision Handling: If two computers send data simultaneously, a collision occurs. The computers then wait for a random period before trying to send again. 

  • Half-Duplex: Communication over a hub is half-duplex, meaning devices can either send or receive data at one time, but not both. 

Analogy: Think of a set of train tracks. If two trains were headed towards each other on the same track, they would collide. Those train tracks are like a collision domain. In networking, the trains colliding are electrical signals and the train tracks are the communication paths they travel on. 

Limitations of Hubs 

  • Performance Issues: As more computers are added, collisions increase, leading to performance slowdowns. 

  • No Gigabit Support: Hubs do not support Gigabit Ethernet, limiting network speed and efficiency. 

  • Replaced by Switches: Because of these limitations, most modern networks now use switches instead of hubs. Hubs are rarely used today, except in specific situations where legacy equipment is still in use. 

In summary, hubs were once a common way to connect devices on a network, but due to performance and speed limitations, they have largely been replaced by more efficient Ethernet switches. 

Switches 

Switches are modern network devices that replaced hubs and solved the issue of collisions in Ethernet networks. They play a central role in almost all office networks today. 

How Switches Work 

  • Ports: Like a hub, a switch provides one port for each device that needs to connect to the network. 

  • Intelligent Forwarding: Unlike a hub, a switch can decode each data frame and read the source and destination MAC addresses. 

  • The switch uses this information to forward the frame only to the port that matches the destination MAC address, rather than sending it to all ports like a hub would. 

Full-Duplex Communication 

  • Each switch port is its own collision domain, meaning no two devices will interfere with each other’s transmissions. 

  • Switches enable full-duplex communication, which means that each connected device can send and receive data at the same time. This improves performance significantly compared to the half-duplex communication of hubs. 

MAC Address Table 

  • Learning MAC Addresses: When a switch receives a data frame, it reads the source MAC address and records which port is associated with that address in its MAC address table. 

  • Unknown Destinations: If the switch has not yet learned the destination MAC address, it will temporarily flood the frame to all ports until it learns the correct port for that destination. 

Key Benefits of Switches 

  • No Collisions: Each port operates independently, eliminating the contention and collisions seen in hub-based networks. 

  • Faster Speeds: Full-duplex communication allows devices to use the full speed supported by their network cabling and NICs (Network Interface Cards). 

  • Efficiency: Switches make networks more efficient by only sending data to the specific device that needs it, reducing unnecessary traffic. 

Switches have become the backbone of modern networks, offering a more reliable, efficient, and collision-free solution compared to older hub-based networks. 

Unmanaged and Managed Switches 

Switches are a key part of network infrastructure, but they come in two main types: unmanaged and managed. Each type has different features and is suited for different environments. 

Unmanaged Switches 

  • Simple Operation: An unmanaged switch requires no configuration. Once powered on and connected to devices, it automatically establishes Ethernet connectivity without any further setup. 

  • Use in Small Networks: These switches are often found in small networks, such as home or small office networks. They typically have 4 or 8 ports.

  • SOHO Router/Modems: Most SOHO (Small Office/Home Office) router/modems provided by Internet Service Providers (ISPs) include an unmanaged 4-port switch to connect devices to the network.

  • Older SOHO Devices: Some older SOHO routers used hubs instead of switches, which do not support 1 Gbps speeds. 

SOHO Router

Managed Switches 

  • Advanced Features: Managed switches are used in larger networks that require more control and flexibility. While they can function like unmanaged switches out of the box, they also offer advanced configuration options. 

  • Security and Customization: A network administrator can access the switch via a management port and configure settings such as security, quality of service (QoS), and traffic control. 

  • Rack-Mounted Design: Managed switches are typically designed to be rack-mounted in network racks, often featuring 24 or 48 ports for connecting multiple devices like PCs, servers, and printers. 

Managed Rack-Mounted Design Switch

  • Uplink Ports: Managed switches also include uplink ports, which allow them to connect to other switches in a larger network setup. 

Modular Switches 

  • Scalability: In large enterprise environments, modular switches are used to connect multiple switch units into one appliance. These switches come with a power supply and a high-speed backplane that connects all the units, allowing for hundreds of access ports in a single device. 

  • Compact Design: Despite their high port count, modular switches are compact and offer a scalable solution for growing networks. 

Configuring Managed Switches 

  • Web Interface or Command Line: Managed switches can be configured via a web interface or command line interface (CLI), allowing administrators to customize their behavior and optimize network performance. 

By choosing the right type of switch, whether unmanaged for smaller networks or managed for larger environments, you can ensure your network operates efficiently and securely. 

Routers 

Routers play a crucial role in connecting different networks and forwarding data between them. Unlike switches and access points that rely on MAC addresses to forward frames within a local network, routers use IP addresses to forward packets across multiple networks (an internetwork), including the private LAN and the public WAN (Internet). 

How Routers Work 

  • MAC vs. IP Addresses: 

    • A MAC address identifies a device’s hardware interface, and is used within local network segments for communication. 

    • An IP address, on the other hand, identifies both the network and the host within that network, allowing devices to communicate across different networks. 

  • Routing Packets: While switches forward data based on MAC addresses, routers route packets using IP addresses, allowing communication between different network segments and over the Internet. 

Types of Routers 

There are different types of routers, depending on the network environment and the tasks they perform: 

SOHO Routers (Small Office/Home Office) 

  • Basic Functionality: A SOHO router typically routes data between the local network (LAN) and the WAN/Internet. 

  • Interfaces: These routers generally have a local Ethernet interface for the LAN and a WAN interface (often connected to a modem) for Internet access. 

WAN or Border Routers 

  • WAN Connectivity: A WAN or border router forwards traffic between a local network and the Internet or over a private WAN link. 

  • Multiple Interfaces: These routers usually have an Ethernet interface for the local network and a digital modem interface for connecting to the WAN. 

LAN Routers 

  • Network Segmentation: A LAN router divides a single physical network into multiple logical subnetworks, each becoming its own broadcast domain. This improves network performance by limiting unnecessary traffic between hosts. 

  • Security Benefits: By dividing networks, LAN routers can apply filtering rules to control which traffic can pass between different logical networks, enhancing security. 

  • Ethernet Interfaces: These routers typically only have Ethernet interfaces for connecting to the local network. 

Key Functions of a Router 

  • Internetwork Communication: Routers enable different network segments to communicate with each other by forwarding data based on IP addresses. 

  • Network Address Translation (NAT): Many routers use NAT to allow multiple devices on a private LAN to share a single public IP address when connecting to the Internet. 

  • Traffic Filtering and Security: Routers can apply firewall rules to filter and secure traffic as it passes between different networks. 

In summary, routers are essential for connecting private local networks to the broader Internet or other networks, ensuring efficient and secure communication across different network segments. 

Summary 

Well done! Those were some pretty dense concepts. Understanding network communications and how tools like NICs, switches, and routers work will set you up for success in managing and building efficient networks. Whether you’re working with small setups or complex environments, this knowledge will help you troubleshoot issues, improve performance, and ensure secure connections. Mastering these fundamentals now will give you a strong foundation for more advanced networking tasks in the future. There’s plenty more to learn about networks, so let's keep going!