Learn Computer Networking

Hidden Windows Networking Features: Powerful Windows Networking Tricks & Commands Every IT Pro Should Know

2026-11-10T09:42:53.820-08:00

Windows Administration

15 Useful Windows Networking Tricks and Tips

Hidden Windows Networking Features You Should Know for Troubleshooting and Management.

1. Find your saved Wi-Fi passwords

You can view the password of a Wi-Fi network previously saved on your own Windows computer.

Step 1: List saved Wi-Fi profiles.

netsh wlan show profiles

Step 2: Display the details of a particular profile.

netsh wlan show profile name="MyWiFi" key=clear

Look for: Key Content : YourWiFiPassword

⚠️ Note: This requires access to the saved profile and administrator privileges. Be careful because the command displays the password in plain text. Only use it on computers and networks you are authorized to access.

2. Check your Wi-Fi signal strength and channel

You don't need additional software to check your current Wi-Fi connection.

netsh wlan show interfaces

Look for: Signal strength (%), Channel number, Radio type, Connection speed, Access point BSSID, and Connected SSID.

To see nearby wireless access points and their signal strengths:

netsh wlan show networks mode=bssid

💡 Practical use: Find out whether a computer is connected to a weak access point or operating on a congested Wi-Fi channel.

3. Generate a complete Wi-Fi connection report

Windows can generate an HTML report containing information about recent Wi-Fi connections, disconnections, adapter information, and connection failures.

Open CMD as Administrator:

netsh wlan show wlanreport

Windows generates an HTML report and displays its location. Open the generated file in a browser to examine wireless connection history and failure information.

4. Find out which application is using a particular port

Suppose you are running XAMPP and want to check which process is using port 8080.

netstat -ano | findstr :8080

Note the PID in the result, then identify the process:

tasklist /FI "PID eq 1234"

💡 Practical use: Troubleshoot Apache port conflicts, local web servers, database services, and other applications.

5. Test whether a particular network port is accessible

You don't need to install a port-scanning utility just to test one TCP port.

Open PowerShell:

Test-NetConnection google.com -Port 443

Test an internal server:

Test-NetConnection 192.168.1.100 -Port 80

Look for TcpTestSucceeded : True, indicating the TCP connection was established successfully.

6. Quickly open Network Connections

Instead of navigating through multiple Control Panel windows, press Windows + R, type:

ncpa.cpl

Press Enter to open the classic Network Connections window to enable/disable adapters, configure IPv4/DNS, and view properties.

7. Turn your Windows computer into a Wi-Fi hotspot

You can share your computer's Internet connection with other devices.

Go to:

Settings → Network & Internet → Mobile hotspot

Select the connection you want to share, configure the hotspot name and password, and enable Mobile hotspot.

8. Access another computer's shared folders without browsing the network

Press Windows + R and enter the IP address or computer name:

\\192.168.1.100  (or  \\COMPUTER-NAME)

Windows will attempt to open available shared resources. Both computers must have appropriate network connectivity, sharing settings, and permissions.

9. Map a shared folder as a network drive

Instead of entering a shared folder address every time, map it as a drive letter:

net use Z: \\192.168.1.100\Shared /persistent:yes

To disconnect it:

net use Z: /delete

10. Change a network between Public and Private

Windows uses network profiles to control network discovery. In PowerShell:

Get-NetConnectionProfile

To set a trusted network to Private:

Set-NetConnectionProfile -InterfaceAlias "Ethernet" -NetworkCategory Private

11. Save your complete network configuration into a text file

Useful before making configuration changes. Run in CMD:

ipconfig /all > "%USERPROFILE%\Desktop\network-info.txt"

12. Quickly check all network adapters using PowerShell

Run the following cmdlet:

Get-NetAdapter | Format-Table Name, Status, LinkSpeed, MacAddress -AutoSize

13. Reconnect to a saved Wi-Fi network using CMD

Connect or disconnect using saved profiles:

netsh wlan connect name="MyWiFi" interface="Wi-Fi"

14. Check whether Windows is using a proxy server

Display WinHTTP proxy configuration:

netsh winhttp show proxy

15. Repair common Windows network problems using one command sequence

Run this robust troubleshooting sequence in CMD as Administrator:

netsh winsock reset
netsh int ip reset
ipconfig /release
ipconfig /renew
ipconfig /flushdns

Restart your computer afterward. ⚠️ Don't use it as a routine maintenance command since it temporarily interrupts active connectivity.

15 Essential Windows Network Commands (CMD & PowerShell)

2026-11-04T09:33:55.861-08:00

Network connectivity problems are among the most common issues encountered by Windows computer users. Whether you are experiencing slow Internet connections, DNS resolution errors, IP address conflicts, or problems connecting to another computer on a local network, Windows provides several built-in networking commands to help identify and troubleshoot these issues.

You do not always need additional software to diagnose network problems. Windows includes powerful command-line tools that allow you to inspect network configurations, test connectivity, examine network routes, identify active connections, and troubleshoot DNS problems.

In this guide, you will learn 15 useful Windows network commands, including practical examples of how to use them in Command Prompt (CMD) and Windows PowerShell. These commands are useful for computer technicians, IT students, network administrators, and anyone who wants to improve their Windows network troubleshooting skills.

In this guide:

How to open Command Prompt and PowerShell
ipconfig
ping
tracert
pathping
nslookup
netstat
arp
route
getmac
netsh wlan
PowerShell networking commands
Practical network troubleshooting examples
Windows network reset commands
Frequently asked questions

How to Open Command Prompt and PowerShell

Before using Windows networking commands, you need to open the appropriate command-line application.

Method 1: Open Command Prompt (CMD)

Press Windows + R on your keyboard.
Type cmd.
Press Enter.

To open Command Prompt with administrator privileges, search for CMD in the Start menu, right-click it, and select Run as administrator.

Method 2: Open Windows PowerShell

Right-click the Start button.
Select Terminal or Windows PowerShell, depending on your Windows version.
If you opened Windows Terminal, select the PowerShell tab.

Most diagnostic commands can be executed without administrator privileges. However, certain configuration and network reset commands require an elevated terminal.

1. ipconfig – Display IP Configuration

The ipconfig command is one of the most frequently used Windows networking commands. It displays the computer's IP configuration, including its IPv4 address, IPv6 address, subnet mask, and default gateway.

Basic command:

ipconfig

Example output:

Ethernet adapter Ethernet:

   IPv4 Address. . . . . . . . . . : 192.168.1.105
   Subnet Mask . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . : 192.168.1.1

Important information:

IPv4 Address: The IP address assigned to the computer.
Subnet Mask: Identifies the network and host portions of the IPv4 address.
Default Gateway: The router or next-hop device used to reach other networks.

Useful ipconfig options

Display complete network configuration:

ipconfig /all

This displays additional information, such as the physical (MAC) address, DHCP status, DNS servers, and DHCP lease information.

Release the current DHCP-assigned IP address:

ipconfig /release

Request a new DHCP IP address:

ipconfig /renew

These two commands are useful when troubleshooting DHCP-related IP configuration problems. They apply to adapters configured to obtain an address automatically. Releasing the address temporarily interrupts connectivity.

Display the DNS cache:

ipconfig /displaydns

Clear the local DNS resolver cache:

ipconfig /flushdns

The last command is particularly useful when troubleshooting website access and DNS resolution problems.

When to use ipconfig: Use this command when you need to check your computer's IP address, default gateway, DNS server, or DHCP configuration.

2. ping – Test Network Connectivity

The ping command tests whether another device or destination responds to ICMP Echo Request messages. It is one of the most useful commands for identifying basic network connectivity problems.

Basic syntax:

ping destination

Example – ping a router:

ping 192.168.1.1

This tests connectivity to a device using the IP address 192.168.1.1, which could be your router.

Ping a website:

ping google.com

This tests connectivity using the destination's hostname and also involves name resolution.

Useful ping options

Send 10 ping requests:

ping google.com -n 10

Continuously ping a destination:

ping google.com -t

Press Ctrl + C to stop the continuous test and display statistics.

Resolve an IP address to a hostname:

ping -a 192.168.1.1

This option attempts to resolve the destination IP address to a hostname before sending the ping requests.

How to use ping for troubleshooting

A useful testing sequence is:

ping 127.0.0.1
ping 192.168.1.1
ping 1.1.1.1
ping google.com

Replace 192.168.1.1 with your actual default gateway. These tests help investigate whether the local TCP/IP stack responds, whether the computer can communicate with its gateway, whether an external IP address responds, and whether a hostname can be resolved and reached.

Important: A failed ping does not always mean a device or network is offline. Firewalls, routers, and remote servers can block or limit ICMP traffic.

When to use ping: Use it to perform a quick connectivity test, identify possible packet loss, and compare hostname-based connectivity with IP-based connectivity.

3. tracert – Trace the Network Route

The tracert command (Trace Route) identifies the intermediate network devices, known as hops, that packets encounter when travelling towards a destination. It helps you understand the route between your computer and another network device or server.

Basic syntax:

tracert destination

Example:

tracert google.com

Windows displays the intermediate hops and the round-trip response times.

Disable hostname resolution for intermediate hops:

tracert -d google.com

This can make the results easier to obtain when reverse DNS lookups are slow.

Limit the maximum number of hops:

tracert -h 15 google.com

This limits the trace to 15 hops.

Understanding tracert results: Each row represents an intermediate hop along the route. The results generally include the hop number, three response-time measurements, and the router IP address or hostname when available.

If you see asterisks (* * *), it does not necessarily mean the route is broken. Some routers do not respond to traceroute probes or may limit ICMP responses.

When to use tracert: Use this command when investigating routing problems, unusual delays, or possible connectivity issues along the path to a remote destination.

4. pathping – Identify Packet Loss and Network Delays

The pathping command combines features of ping and tracert. While tracert identifies the route towards a destination, pathping performs additional measurements to estimate packet loss and latency at intermediate hops.

Basic syntax:

pathping destination

Example:

pathping google.com

The command sends multiple probes to routers along the route and calculates packet-loss statistics. It may take several minutes to complete because it collects measurements over time.

When to use pathping: Use it when investigating possible packet loss, unstable network connections, and communication delays between networks.

5. nslookup – Troubleshoot DNS Problems

DNS (Domain Name System) translates domain names into IP addresses. For example, when you enter a website address into your browser, DNS helps your computer locate the corresponding server IP address.

The nslookup command helps you investigate DNS resolution problems.

Basic syntax:

nslookup domain-name

Example:

nslookup google.com

The output displays the DNS server used for the query and the returned DNS records.

Useful nslookup examples

Query a specific DNS server:

nslookup google.com 1.1.1.1

This sends the query to the DNS server at 1.1.1.1.

Check an IPv4 A record:

nslookup -type=A google.com

Check an IPv6 AAAA record:

nslookup -type=AAAA google.com

When to use nslookup: Use it when websites cannot be accessed by domain name, DNS records need to be checked, or you want to compare responses from different DNS servers.

6. netstat – Display Active Network Connections

The netstat command displays information about active network connections, listening ports, and network statistics. It is particularly useful when investigating which ports are being used by applications and services.

Basic command:

netstat

Useful netstat options

Display all connections and listening ports:

netstat -a

Display connections using numerical IP addresses and port numbers:

netstat -n

Display connections with their process IDs (PIDs):

netstat -o

Display all connections with numerical addresses and process IDs:

netstat -ano

Refresh the connection information every five seconds:

netstat -ano 5

Press Ctrl + C to stop.

Understanding netstat output

Proto  Local Address       Foreign Address       State        PID

TCP    192.168.1.105:50432  142.250.190.14:443    ESTABLISHED  2456
TCP    0.0.0.0:80           0.0.0.0:0             LISTENING    1200

Proto: Communication protocol, such as TCP.
Local Address: Local IP address and port.
Foreign Address: Remote IP address and port.
State: Current TCP connection state.
PID: Process ID associated with the connection.

You can identify the application associated with a PID using:

tasklist /FI "PID eq 2456"

Replace 2456 with the PID you want to investigate.

When to use netstat: Use it to investigate open ports, active TCP connections, and applications communicating over the network.

7. arp – Display IP and MAC Address Mappings

ARP stands for Address Resolution Protocol. In an IPv4 Ethernet network, ARP helps a device determine the MAC address associated with an IPv4 address on the local network.

Windows maintains an ARP cache containing recently learned IP-to-MAC address mappings.

Display the ARP cache:

arp -a

Example output:

Interface: 192.168.1.105

Internet Address      Physical Address      Type

192.168.1.1           AA-BB-CC-11-22-33     dynamic
192.168.1.10          AA-BB-CC-44-55-66     dynamic

The Internet Address represents the IPv4 address, while the Physical Address represents the associated MAC address.

Useful arp options

Display the ARP cache for a specific local interface:

arp -a -N 192.168.1.105

Delete a specific ARP cache entry:

arp -d 192.168.1.10

Deleting an entry changes the local ARP cache; Windows can learn the mapping again when it is needed.

When to use arp: Use it when investigating local network IP-to-MAC mappings, checking which devices have recently been resolved by your computer, or troubleshooting local network communication.

8. route – Display the IP Routing Table

The route command allows you to view and modify the computer's IP routing table. The routing table determines where network packets should be forwarded to reach different destinations.

Display the routing table:

route print

This displays IPv4 and IPv6 routing information. The routing table contains information about network destinations, subnet masks or prefixes, gateway addresses, network interfaces, and route metrics.

Display the IPv4 routing table:

route print -4

Display the IPv6 routing table:

route print -6

When to use route: Use this command when investigating routing problems, multiple network interfaces, VPN connections, or unexpected network paths.

Warning: The route command can also modify routing configurations. Avoid using commands such as route add, route change, and route delete unless you understand the routing configuration you intend to change.

9. getmac – Find the MAC Address of Network Adapters

Every network adapter has a physical address, commonly known as a MAC address. The getmac command displays MAC addresses associated with network adapters.

Basic command:

getmac

Display detailed adapter information:

getmac /v

Display results in a table:

getmac /fo table

When to use getmac: Use it when identifying network adapters, recording hardware addresses, configuring MAC-based access controls, or checking the physical addresses required for network administration.

10. netsh wlan – Check Wi-Fi Network Information

The netsh wlan command provides useful information about wireless network interfaces and available Wi-Fi networks. It is particularly helpful when investigating wireless connectivity problems.

Display wireless network interfaces:

netsh wlan show interfaces

The output may include the Wi-Fi interface name, connected SSID, BSSID (access point MAC address), connection state, signal strength, radio type, channel, and connection and receive rates.

Display nearby Wi-Fi networks:

netsh wlan show networks

Display nearby Wi-Fi networks with BSSID information:

netsh wlan show networks mode=bssid

This provides additional wireless access point information, including BSSID and signal strength.

Display installed Wi-Fi driver information:

netsh wlan show drivers

Generate a wireless network report:

netsh wlan show wlanreport

This generates an HTML report containing information about recent wireless sessions and connection events.

When to use netsh wlan: Use it when diagnosing Wi-Fi connection problems, checking signal strength, inspecting available wireless networks, and investigating wireless adapter or driver issues.

Useful Windows PowerShell Networking Commands

In addition to traditional CMD commands, Windows PowerShell includes networking cmdlets that provide more structured diagnostic information. These commands are especially useful for computer technicians and network administrators.

11. Get-NetIPConfiguration – View Network Configuration

The Get-NetIPConfiguration cmdlet displays IP configuration information for network interfaces.

Command:

Get-NetIPConfiguration

Display more detailed information:

Get-NetIPConfiguration -Detailed

Display all network interfaces, including disconnected and virtual interfaces:

Get-NetIPConfiguration -All

It provides information about network interfaces, IP addresses, gateways, and DNS servers.

When to use it: Use this cmdlet when you need a structured view of the computer's network configuration using PowerShell.

12. Get-NetAdapter – Check Network Adapter Status

The Get-NetAdapter cmdlet displays the installed network adapters and their basic properties.

Command:

Get-NetAdapter

Display physical network adapters only:

Get-NetAdapter -Physical

Display selected adapter information in a table:

Get-NetAdapter | Format-Table -AutoSize Name, Status, LinkSpeed, MacAddress

The output helps you identify the adapter name, connection status, link speed, and MAC address.

When to use it: Use this command to investigate network adapter status, confirm whether an Ethernet or Wi-Fi adapter is connected, and inspect adapter link speeds.

13. Test-NetConnection – Test TCP Port Connectivity

The Test-NetConnection cmdlet is one of the most useful PowerShell networking tools. It can test network reachability, perform route tracing, and check whether a specific TCP port is accessible on a remote system.

Basic connectivity test:

Test-NetConnection google.com

Test a specific TCP port:

Test-NetConnection google.com -Port 443

This checks whether a TCP connection can be established to port 443 on the remote destination.

Test HTTP port 80:

Test-NetConnection example.com -Port 80

Trace the network route:

Test-NetConnection google.com -TraceRoute

Understanding the result

ComputerName     : google.com
RemotePort       : 443
TcpTestSucceeded : True

If TcpTestSucceeded is True, the TCP connection to the specified port was established successfully.

If it is False, the connection attempt did not succeed. Possible causes include firewalls, routing problems, unavailable services, or blocked ports.

When to use Test-NetConnection: Use it when testing whether a particular network service or TCP port is reachable, especially when troubleshooting servers, web applications, and network services.

14. Resolve-DnsName – Perform DNS Queries Using PowerShell

Resolve-DnsName is a PowerShell cmdlet that performs DNS queries. It provides functionality similar to the traditional nslookup command.

Basic command:

Resolve-DnsName google.com

Query IPv4 records:

Resolve-DnsName google.com -Type A

Query IPv6 records:

Resolve-DnsName google.com -Type AAAA

Use a specific DNS server:

Resolve-DnsName google.com -Server 1.1.1.1

When to use Resolve-DnsName: Use it when troubleshooting DNS resolution, examining DNS records, or testing the responses returned by a particular DNS server.

15. Get-NetTCPConnection – Examine Active TCP Connections

The Get-NetTCPConnection cmdlet displays current TCP connection information using PowerShell. It provides details about local and remote addresses, port numbers, and connection states.

Display all current TCP connections:

Get-NetTCPConnection

Display established TCP connections only:

Get-NetTCPConnection -State Established

Display connections using a specific local port:

Get-NetTCPConnection -LocalPort 443

Display the process ID associated with each connection:

Get-NetTCPConnection | Select-Object LocalAddress, LocalPort, RemoteAddress, RemotePort, State, OwningProcess

When to use Get-NetTCPConnection: Use it when examining active TCP sessions, investigating local ports, and identifying which processes own network connections.

Practical Windows Network Troubleshooting Guide

Knowing individual networking commands is useful, but understanding when and how to combine them is even more important. The following examples demonstrate how to use the commands to investigate common Windows networking problems.

Scenario 1: Computer Connected to the Network but Has No Internet Access

Start by checking the IP configuration:

ipconfig /all

Check whether the computer has a valid IP address, subnet mask, default gateway, and DNS server.

Next, test the local TCP/IP stack:

ping 127.0.0.1

Test communication with the default gateway:

ping 192.168.1.1

Replace the example gateway address with the actual default gateway shown by ipconfig.

Test an external IP address:

ping 1.1.1.1

Finally, test domain name resolution and connectivity:

ping google.com

A successful test at one stage and a failed test at the next stage can help narrow down where the problem may exist. Remember that ICMP traffic may be blocked, so a failed ping alone is not conclusive.

Scenario 2: Websites Cannot Be Opened by Domain Name

When a computer appears to have network connectivity but websites cannot be accessed by their domain names, investigate DNS.

First, inspect the DNS configuration:

ipconfig /all

Check the DNS server addresses. Test DNS resolution:

nslookup google.com

Clear the local DNS cache:

ipconfig /flushdns

Perform the query again:

nslookup google.com

If the problem continues, compare the response from another DNS server:

nslookup google.com 1.1.1.1

This helps determine whether the problem may be related to the configured DNS server or local DNS resolution.

Scenario 3: Check Whether a Web Server Is Accessible

Suppose you have a local or remote web server and want to check whether its HTTPS port is reachable. Open PowerShell and enter:

Test-NetConnection 192.168.1.50 -Port 443

Replace the example IP address with your actual server address. Check the TcpTestSucceeded result:

True: A TCP connection to port 443 was successfully established.
False: The TCP connection could not be established.

This tests TCP connectivity, not whether the website itself is functioning correctly.

Scenario 4: Investigate a Slow or Unstable Network Connection

Start with a continuous ping test:

ping 192.168.1.1 -t

This helps monitor communication with the local gateway. Then examine the network route:

tracert google.com

For additional packet-loss information:

pathping google.com

These commands can help investigate latency and possible packet loss along the network path.

Scenario 5: Check Which Application Is Using a Network Port

Open Command Prompt and execute:

netstat -ano

Identify the connection or port you want to investigate and note its PID. For example:

TCP    0.0.0.0:8080    0.0.0.0:0    LISTENING    2456

Use the PID to identify the application:

tasklist /FI "PID eq 2456"

This helps identify which process is associated with the listening port.

Bonus: Windows Network Reset Commands

Sometimes Windows networking components may require repair after configuration problems or software-related network issues. The following commands can reset important network components. They should be used carefully because they modify system configuration.

Reset the Winsock catalog:

netsh winsock reset

Reset the TCP/IP configuration:

netsh int ip reset resetlog.txt

Run Command Prompt as administrator when executing these commands. Restart Windows after completing the resets.

Important: These are not routine troubleshooting commands. They may affect custom network configurations and should only be used when appropriate. Record important settings, such as static IP and DNS configurations, before attempting a reset.

Frequently Asked Questions (FAQ)

1. What is the most useful Windows network command?

ipconfig is one of the most useful commands because it displays essential IP configuration information, including IP addresses, subnet masks, default gateways, and DNS settings. However, ping is particularly useful for basic connectivity testing.

2. How can I find my computer's IP address using CMD?

Open Command Prompt and enter:

ipconfig

Find the IPv4 Address entry under the connected network adapter.

3. How can I check whether my Internet connection is working using CMD?

You can try:

ping 1.1.1.1

However, the destination or network may block ICMP requests. For a better diagnostic sequence, test your gateway, an external IP address, and a domain name.

4. What command displays all active network connections in Windows?

Use:

netstat -ano

It displays active TCP connections and listening ports with their process IDs.

5. How can I check my DNS server using CMD?

Use:

ipconfig /all

Look for the DNS Servers entry under your connected network adapter.

6. What is the difference between tracert and pathping?

tracert identifies the intermediate hops along a network path. pathping performs additional measurements to estimate packet loss and latency at those intermediate hops.

7. Can I run CMD networking commands in PowerShell?

Yes. Most Windows networking command-line executables, such as ipconfig, ping, nslookup, and netstat, can also be executed from PowerShell. PowerShell additionally provides networking cmdlets such as Get-NetAdapter, Get-NetIPConfiguration, and Test-NetConnection.

Conclusion

Windows provides a comprehensive collection of built-in networking commands that can help diagnose and troubleshoot many common network problems.

Whether you are a beginner learning computer networking or an experienced IT technician managing network devices, understanding these commands is an important practical skill.

Start by learning ipconfig, ping, tracert, nslookup, and netstat. Once you are comfortable with these commands, explore the PowerShell networking cmdlets to perform more detailed network diagnostics.

Save this guide as a reference whenever you need to troubleshoot a Windows network connection.

Official References and Further Reading

The following Microsoft Learn resources provide additional technical information about the commands covered in this article.

The 7 Layers of the OSI Model: The Ultimate Beginner’s Guide

2026-07-26T11:26:42.330-07:00

Have you ever wondered how an email sent from a laptop in New York lands in an inbox in Tokyo in a matter of seconds? To the untrained eye, it looks like digital magic. In reality, it relies on a universally standardized framework known as the OSI Model.

Understanding the OSI model is the ultimate rite of passage for network engineers, cybersecurity professionals, and developers alike. In this SEO-optimized guide, we will break down what the OSI model is, why it still matters, and exactly how data travels through all 7 layers.

What is the OSI Model?

The OSI (Open Systems Interconnection) Model is a conceptual framework created by the International Organization for Standardization (ISO) in 1984. It standardizes the functions of a telecommunication or computing system into seven distinct, abstract layers.

Think of the OSI model as a universal translator for computers. Before its inception, different computer manufacturers built hardware that could only talk to devices made by the same company. The OSI model created a set of international rules, ensuring that a Linux server, a Windows PC, an Apple iPhone, and a Cisco router can all seamlessly communicate.

The 7 Layers of the OSI Model (From Top to Bottom)

When data is sent, it travels from Layer 7 down to Layer 1. When data is received, it travels from Layer 1 back up to Layer 7. Let’s break down each layer’s unique responsibility.

[7] Application Layer (Data)

[6] Presentation Layer (Data)

[5] Session Layer (Data)

[4] Transport Layer (Segments)

[3] Network Layer (Packets)

[2] Data Link Layer (Frames)

[1] Physical Layer (Bits)

Layer 7: The Application Layer

Data Unit: Data

What it does: This is the only layer that directly interacts with software applications and the user. When you open a web browser or an email client, Layer 7 protocols are triggered to initiate network communication.

Real-World Protocols: HTTP, HTTPS, SMTP (email), FTP (file transfer), DNS.

Layer 6: The Presentation Layer

Data Unit: Data

What it does: This layer acts as the "translator" and formatting hub for the network. It takes the data from the Application Layer and prepares it for transmission by handling three critical tasks: translation (e.g., converting ASCII to EBCDIC), encryption/decryption (for security), and compression (reducing data size).

Real-World Examples: SSL/TLS, JPEG, GIF, MP3.

Layer 5: The Session Layer

Data Unit: Data

What it does: The Session layer acts as the coordinator. It sets up, manages, synchronizes, and terminates communication dialogues between two devices. It ensures that sessions remain open long enough to transfer data, and closes them immediately afterward to prevent resource wastage.

Real-World Protocols: NetBIOS, RPC, PPTP.

Layer 4: The Transport Layer

Data Unit: Segments

What it does: This layer is responsible for end-to-end communication, flow control, and error checking. It chops data up into smaller pieces called segments on the sending end and reassembles them on the receiving end.

Real-World Protocols: TCP (Transmission Control Protocol, which prioritizes absolute accuracy and packet tracking) and UDP (User Datagram Protocol, which prioritizes speed for streaming and gaming).

Layer 3: The Network Layer

Data Unit: Packets

What it does: The Network layer handles the logical routing of data. It takes the segments from Layer 4, adds the sender and receiver's IP addresses, and turns them into packets. It determines the best, fastest, and most efficient physical path for data to travel across different networks.

Real-World Hardware & Protocols: Routers, IPv4, IPv6, ICMP.

Layer 2: The Data Link Layer

Data Unit: Frames

What it does: While the Network Layer handles routing between different networks, the Data Link layer handles data transfer between devices on the same local network. It packs packets into frames and uses physical addresses (MAC addresses) to move data from one local hardware device to another.

Real-World Hardware & Protocols: Network Switches, Ethernet, Wi-Fi (802.11), PPP.

Layer 1: The Physical Layer

Data Unit: Bits

What it does: The lowest layer deals purely with raw, unstructured digital data—represented as bits (0s and 1s). It encompasses the actual physical hardware, cables, and electrical, radio, or optical signals used to physically move data from point A to point B.

Real-World Hardware: Fiber-optic cables, Cat6 Ethernet cables, network hubs, repeaters.

Why is the OSI Model Still Relevant?

Even though the modern internet runs practically on a slightly streamlined model called the TCP/IP suite, the OSI Model remains the gold standard for networking education and troubleshooting.

Pinpoint Troubleshooting: When a network goes down, the OSI model allows tech professionals to isolate the issue. If a website won't load, checking if the Ethernet cable is plugged in eliminates Layer 1 issues; checking if you can ping the router eliminates Layer 3 issues.

Modular Development: It allows hardware vendors and software developers to build products that work together. A cable manufacturer can design a new Layer 1 fiber cable without needing to worry about what Layer 7 software application will run over it.

Summary Cheat Sheet for Tech Interviews

Application (7): Network services to applications.

Presentation (6): Data representation, encryption, and translation.

Session (5): Inter-host communication management.

Transport (4): End-to-end connections, segmentation, and reliability (TCP/UDP).

Network (3): Path determination and logical addressing (IP).

Data Link (2): Physical addressing (MAC) and LAN switching.

Physical (1): Binary transmission over cables and signals.

Need an easy way to remember the order? Just use the classic tech acronym mnemonic: Please Do Not Throw Sausage Pizza Away (Physical, Data Link, Network, Transport, Session, Presentation, Application).

IPv4 vs. IPv6: The Fundamental Difference (And Why the Switch Matters)

2026-07-24T12:07:03.447-07:00

The fundamental difference between IPv4 and IPv6 comes down to space and scale. Internet Protocol (IP) addresses are unique numerical labels assigned to every device connected to a computer network; think of them like digital phone numbers that allow your phone, laptop, or smart TV to find and talk to one another across the internet.

While both versions serve the exact same core purpose, the structural engine behind them has changed drastically. Here is a deep dive into the technical differences, why the world is aggressively transitioning, and what it means for the future of IT infrastructure.

1. What is IPv4? The Internet's Legacy Framework

Launched in 1983 by ARPANET, IPv4 (Internet Protocol version 4) is the fourth iteration of the internet protocol and the first to be widely deployed.

Structure: It uses a 32-bit address space, which translates to numbers written in a dotted-decimal format (e.g., 192.168.1.1).
Capacity Limit: A 32-bit mathematical architecture allows for exactly 2^32, or roughly 4.3 billion unique addresses.

When the protocol was built, 4.3 billion addresses seemed virtually inexhaustible. However, developers in the 1980s did not foresee the mobile revolution, cloud computing, or the smart device boom.

2. What is IPv6? The Next-Generation Solution

Recognizing that the internet would eventually outgrow IPv4, the Internet Engineering Task Force (IETF) finalized IPv6 (Internet Protocol version 6) in the late 1990s as a permanent replacement.

Structure: IPv6 uses a massive 128-bit address space. Instead of standard numbers, it relies on hexadecimal notation, separated by colons (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334).
Capacity Limit: Mathematically, this provides 2^128 addresses. That translates to approximately 340 undecillion unique addresses.

To put 340 undecillion in perspective: You could assign a unique IP address to every single grain of sand on Earth, and still have enough left over to populate millions of more planets.

3. Side-by-Side Comparison: IPv4 vs. IPv6

To fully understand how these protocols differ operationally, we have to look past the character length:

Technical Feature	IPv4	IPv6
Address Bit-Length	32-bit	128-bit
Notation Style	Dotted Decimal (`192.0.2.1`)	Hexadecimal Colons (`2001:db8::1`)
Address Capacity	~4.3 Billion	~340 Undecillion
Packet Header Size	Variable (20 to 60 bytes)	Fixed (40 bytes)
Security (IPsec)	Optional (must be manually integrated)	Mandatory (built natively into the core layout)
Address Allocation	Handled manually or via DHCP	Uses Stateless Address Autoconfiguration (SLAAC)
Data Packet Routing	Less efficient due to variable header sizes	Highly efficient processing for network routers

4. Why the World is Transitioning to IPv6

The shift to IPv6 is no longer optional—it is actively occurring due to structural network demands:

The Exhaustion of IPv4 Addresses

The internet officially depleted its pool of unallocated IPv4 addresses at the top-level Regional Internet Registries (RIRs) years ago. Today, IPv4 addresses are treated like premium digital real estate, trading on secondary transfer markets for $50 to $65 per IP address.

The Internet of Things (IoT) Explosion

Modern networks do not just host computers and servers. We now connect smart cars, medical monitors, industrial sensors, and smart home appliances. The sheer density of modern connected hardware absolutely requires the near-infinite room provided by IPv6.

Eliminating the "NAT" Band-Aid

To stretch the lifespan of IPv4, network engineers created NAT (Network Address Translation). NAT allows an entire home or office building to share one public IPv4 address while assigning private addresses internally. While clever, NAT creates latency, introduces security hurdles, and complicates peer-to-peer communication. IPv6 completely eliminates the need for NAT, restoring true end-to-end device communication.

Native Data Security

IPv6 was built from the ground up to support IPsec (Internet Protocol Security). This means packet authentication, data integrity, and traffic encryption are woven straight into the fabric of the protocol, rather than bolted on as an afterthought like in IPv4.

5. The Current State of the Transition

If IPv6 is so vastly superior, why hasn't IPv4 disappeared entirely?

IPv4 and IPv6 are not backward-compatible. A device configured only to speak IPv4 cannot inherently talk to a device running only on IPv6. Upgrading global enterprise switches, home routers, and legacy banking or government software takes immense capital and time.

Because of this hurdle, the internet currently operates in a "Dual-Stack" status. Modern network infrastructure runs both protocols side-by-side.

Global user connectivity to Google over IPv6 sits at roughly 50.9%, meaning the internet is operating right at its historical tipping point where IPv6 is transitioning from an alternative option into the global majority standard.

Subnetting Lesson (Easy Step-by-Step Method)

2026-06-22T11:16:30.740-07:00

Subnetting Lesson (Easy Step-by-Step Method)

Lesson Title

Introduction to IPv4 Subnetting

Learning Outcomes

By the end of this lesson, students will be able to:

Explain what subnetting is.
Identify Network ID and Host ID.
Calculate subnet masks.
Determine the number of subnets.
Determine the number of hosts per subnet.
Find the network address, first host, last host, and broadcast address.

1. What is Subnetting?

Subnetting is the process of dividing one large network into smaller networks (subnets).

Why do we use subnetting?

✅ Reduces network traffic

✅ Improves security

✅ Makes network management easier

✅ Uses IP addresses efficiently

Real-World Example

Imagine a school with 300 computers.

Instead of one large network:

Department	Subnet
Administration	Subnet 1
Computer Lab	Subnet 2
Library	Subnet 3
Staff Room	Subnet 4

Each department becomes a separate subnet.

2. IPv4 Address Structure

An IPv4 address contains 32 bits.

Example:


192.168.1.10

Binary form:


11000000.10101000.00000001.00001010

32 bits = 4 octets × 8 bits


192      168      1       10
11000000 10101000 00000001 00001010

3. Network Portion and Host Portion

Example:


192.168.1.10/24

The "/24" means:


24 bits = Network
8 bits = Host


192.168.1 .10
Network   Host

4. Understanding CIDR Notation

CIDR	Subnet Mask
/8	255.0.0.0
/16	255.255.0.0
/24	255.255.255.0
/25	255.255.255.128
/26	255.255.255.192
/27	255.255.255.224
/28	255.255.255.240
/29	255.255.255.248
/30	255.255.255.252

5. Easy 4-Step Subnetting Method

Step 1 – Identify CIDR

Example:


192.168.1.0/26

CIDR = 26

Step 2 – Find Block Size

Formula:


Block Size = 256 − Last Octet of Subnet Mask

For /26:


Subnet Mask = 255.255.255.192

256 - 192 = 64

Block size = 64

Step 3 – Create Network Ranges

Start at 0 and count by block size.

Subnets:

Subnet
192.168.1.0
192.168.1.64
192.168.1.128
192.168.1.192

Step 4 – Find Host Range and Broadcast

First Subnet

Network:


192.168.1.0

Next subnet:


192.168.1.64

Broadcast:


64 - 1 = 63

Broadcast = 192.168.1.63

Host range:


192.168.1.1
to
192.168.1.62

Quick Formula


Network Address = First Address

Broadcast Address = Last Address

First Host = Network + 1

Last Host = Broadcast - 1

6. Host Calculation

Formula:


Hosts = 2^(Host Bits) - 2

Example 1

Network:

/24

Host bits:


32 - 24 = 8

Calculation:


2^8 - 2

256 - 2

254 Hosts

Example 2

Network:

/26

Host bits:


32 - 26 = 6

Calculation:


2^6 - 2

64 - 2

62 Hosts

7. Subnet Calculation

Formula:


Subnets = 2^(Borrowed Bits)

Example:

Default Class C:

/24

New subnet:

/27

Borrowed bits:


27 - 24 = 3

Calculation:


2^3

8 Subnets

Easy Reference Table

CIDR	Hosts
/24	254
/25	126
/26	62
/27	30
/28	14
/29	6
/30	2

8. Complete Example

Find subnet information for:


192.168.10.0/27

Step 1

Subnet mask:


255.255.255.224

Step 2

Block size:


256 - 224

32

Step 3

Subnets

Step 4

First subnet:

Network:


192.168.10.0

Broadcast:


192.168.10.31

Host range:


192.168.10.1
to
192.168.10.30

Hosts:

Classroom Activity 1

Complete the table.

CIDR	Subnet Mask	Hosts
/25	?	?
/26	?	?
/27	?	?
/28	?	?

Answers

CIDR	Subnet Mask	Hosts
/25	255.255.255.128	126
/26	255.255.255.192	62
/27	255.255.255.224	30
/28	255.255.255.240	14

Classroom Activity 2

Find:


192.168.5.0/28

Network Address
Broadcast Address
First Host
Last Host
Number of Hosts

Answer

Network:


192.168.5.0

Broadcast:


192.168.5.15

First Host:


192.168.5.1

Last Host:


192.168.5.14

Hosts:

Memory Trick for Students

1. Find the mask


/27 = 255.255.255.224

2. Find block size


256 - 224 = 32

3. Count by block size


0, 32, 64, 96, 128...

4. Use the range


Network = Start
Broadcast = End
Hosts = Middle

Golden Rule:

Network Address = First IP
Broadcast Address = Last IP
Usable Hosts = Everything in between

This method allows most Class C subnetting questions (/25 to /30) to be solved in less than one minute without converting IP addresses to binary.

How to Make a Network Cable (UTP Ethernet Cable)

2026-06-01T09:31:41.773-07:00

Module: Setup and Maintain Network Systems

Task: Terminate a UTP Cable Using RJ45 Connectors

Objective

After completing this activity, you will be able to:

Identify cable termination tools and materials.
Prepare a UTP cable correctly.
Arrange wires according to T568A and T568B standards.
Crimp an RJ45 connector properly.
Test the completed cable for correct operation.

Required Tools and Materials

Materials

UTP Cable (Cat5e/Cat6)
RJ45 Connectors (2 pcs)

Tools

Crimping Tool
Wire Cutter
Cable Stripper
Network Cable Tester

Safety Precautions

✓ Handle the crimping tool carefully.

✓ Do not use damaged connectors.

✓ Keep the cable free from sharp bends.

✓ Ensure hands are dry when working.

✓ Keep the work area clean and organized.

Understanding Wire Standards

There are two standard wiring schemes:

T568A

Pin	Color
1	White/Green
2	Green
3	White/Orange
4	Blue
5	White/Blue
6	Orange
7	White/Brown
8	Brown

T568B (Most Common)

Pin	Color
1	White/Orange
2	Orange
3	White/Green
4	Blue
5	White/Blue
6	Green
7	White/Brown
8	Brown

Procedure Guide

Step 1 – Measure and Cut the Cable

Determine the required cable length.
Add approximately 10 cm extra length.
Cut the cable cleanly using a cable cutter.

Check Point

✓ Cable length is correct.

✓ Cable end is cut straight.

Step 2 – Strip the Outer Jacket

Place the cable in the stripping section of the crimping tool.
Rotate gently around the cable.
Remove approximately 25 mm (1 inch) of outer jacket.

Important

⚠ Do not cut or damage the inner conductors.

Check Point

✓ All 8 conductors are intact.

✓ No insulation damage.

Step 3 – Untwist the Pairs

Inside the cable there are four twisted pairs:

Orange Pair
Green Pair
Blue Pair
Brown Pair

Carefully untwist the conductors.
Untwist only the amount needed.

Important

⚠ Excessive untwisting reduces cable performance.

Check Point

✓ Wires remain smooth and undamaged.

Step 4 – Arrange Wires in Correct Order

For this exercise use T568B.

Arrange wires from left to right:

Pin	Color
1	White/Orange
2	Orange
3	White/Green
4	Blue
5	White/Blue
6	Green
7	White/Brown
8	Brown

Procedure

Hold wires between fingers.
Straighten each conductor.
Place them in exact order.
Verify the color sequence carefully.

Check Point

✓ Correct color order.

✓ Wires are straight.

✓ No crossed conductors.

Step 5 – Trim Conductors

Hold the arranged conductors firmly.
Cut all wires evenly.
Leave approximately 12–13 mm (½ inch) exposed.

Important

⚠ All conductors must be exactly the same length.

Check Point

✓ Wire ends are even.

✓ Length is suitable for insertion.

Step 6 – Insert Wires into RJ45 Connector

Hold the RJ45 connector with:
- Clip facing downward.
- Gold contacts facing upward.
Carefully insert the conductors.
Push fully until:
- Every wire reaches the front end.
- Cable jacket enters the connector.

Important

⚠ The outer jacket must enter the connector for strength.

Verify visually:

Item	Yes/No
Correct wire order	[ ]
All wires fully inserted	[ ]
Wire tips visible at front	[ ]
Jacket inside connector	[ ]

Step 7 – Crimp the Connector

Insert the RJ45 connector into the crimping tool.
Squeeze the handles completely.
Release and remove the connector.

What Happens During Crimping

Gold pins pierce conductor insulation.
Pins make electrical contact.
Strain relief locks onto cable jacket.

Check Point

✓ Connector is firmly attached.

✓ No loose conductors.

✓ Connector does not pull off easily.

Step 8 – Terminate the Other End

Straight-Through Cable

Use T568B on both ends

Most commonly used for:

PC to Switch
PC to Router
Printer to Switch

Crossover Cable

End A	End B
T568A	T568B

Used mainly for older devices.

Step 9 – Test the Cable

Procedure

Connect one end to the Main Tester.
Connect the other end to the Remote Tester.
Switch on the tester.

Expected Result

LED sequence:

1 → 2 → 3 → 4 → 5 → 6 → 7 → 8

Fault Indications

Fault	Possible Cause
No light	Broken wire
Wrong sequence	Incorrect wiring
Missing pin	Poor crimping
Multiple lights	Short circuit

Check Point

✓ All 8 LEDs illuminate correctly.

✓ Sequence is correct.

Final Inspection Checklist

Item	Pass
Cable length correct	□
Jacket not damaged	□
Correct T568B order	□
Wires trimmed evenly	□
Wires fully inserted	□
Jacket inside connector	□
Connector crimped correctly	□
Cable tester passed	□

Common Mistakes to Avoid

❌ Wrong color sequence.

❌ Excessive untwisting.

❌ Uneven conductor lengths.

❌ Cable jacket outside connector.

❌ Incomplete crimping.

❌ Using damaged RJ45 connectors.

❌ Forgetting to test the cable.

✅ Try Sinhala version

What is a Computer Network

2025-09-20T14:37:00.000-07:00

Networking Fundamentals

What is a Computer Network? Definition & Classifications

The backbone of global communication, digital business, and modern connectivity.

A Computer Network is an interconnection of two or more autonomous computing devices designed to share hardware resources (such as printers and storage), software services, and exchange digital information.

In today’s digital age, computer networking forms the absolute backbone of global communication, remote work, enterprise operations, and the internet itself. To truly understand how data moves across the globe, we must examine how networks are structured and categorized based on their geographic scope, scale, and topology.

Classification by Size and Geographic Scope

1. PAN (Personal Area Network)

Smallest Scale (Range: ~10 meters)

Centered around a single individual in a single location. Examples include connecting your smartphone to wireless Bluetooth earbuds, a smartwatch, or a wireless mouse to your laptop.

2. LAN (Local Area Network)

High Speed & Secure

Connects computers and network devices within a limited geographic area such as a home, school, office building, or hospital. LANs offer exceptionally high data-transfer speeds and private resource sharing.

3. CAN (Campus Area Network)

Larger than LAN

Larger than a LAN but smaller than a MAN. It connects multiple LANs across a specific geographic campus, such as a university or a large corporate headquarters.

4. MAN (Metropolitan Area Network)

City-Wide Scope

Covers a larger geographic area than a LAN or CAN, typically spanning an entire city or town. Often owned by a consortium of users or a single network service provider (telecom operator).

5. WAN (Wide Area Network)

Global Scale

Connects multiple smaller networks across massive geographical distances, spanning countries or continents. The Internet is the largest and most well-known public WAN in existence.

Hardware Components of a Computer Network

2025-09-19T14:00:00.000-07:00

Networking Fundamentals

Hardware Components of a Computer Network

Explore the physical devices that power modern network communication and data sharing.

A computer network typically consists of various hardware components that work together to facilitate communication and data sharing between devices. Some of the most common hardware components of a computer network include:

Network interface card (NIC)

A Network card is a hardware device that uses to connect computers together in Network. The network card is also known as a network adapter. Each computer must have a Network card in order to connect to the network. Most modern computers come with built-in Network cards. If you are using a wireless network you must have a wireless Network interface card to connect to the Network.

💡 Technical Note: Operates at both Layer 1 (Physical) and Layer 2 (Data Link) of the OSI model. Each NIC is assigned a unique burned-in physical address known as a MAC address (Media Access Control) during manufacturing.

Switches

A switch is an active device that connects two or more network segments together at same time in a network. Switches have become an increasingly important part of our networking today because nowadays every networks use the Star topology. In star topology a switch is use as the central device. The switch acts as a filtering device by associating the MAC address of the system connected to the switch with the port on the switch. Each switch contains a certain number of ports, typically 8, 16, 24 or 48. Also Switches can be connected to each other to build larger networks. But switch is an expensive device.

💡 Technical Note: Operates at Layer 2 (Data Link Layer). Unlike hubs, switches create dedicated temporary micro-segments and forward data frames only to the specific destination port using a MAC address table.

Router

Routers are packet-forwarding devices just like switch. Routers allow transmission of data between network segments. Unlike switches, it transmits data packets based on physical node addresses. Router is the device that connects two different networks together. Router is a Network layer device, so it can work with the network packets at a higher level. So how do routers work? In the case of the IP protocol, an IP address is 32 bits long. Those 32 bits contain both the network ID and the host ID of a network device. IP distinguishes between network and host bits by using a subnet mask.

💡 Technical Note: Operates at Layer 3 (Network Layer). Routers use routing tables and protocols (like OSPF, BGP) to determine the most efficient path across different networks (e.g., connecting a home LAN to the WAN/Internet).

Modems

Modems are used to connect networks to the internet by converting digital signals from a computer into analog signals that can be transmitted over a telephone line or cable.

💡 Technical Note: The word "Modem" stands for Modulator-Demodulator. It modulates digital data into analog for transmission and demodulates incoming analog signals back into digital bits.

Hubs

Hubs are similar to switches, but they do not perform any filtering or forwarding of data packets.

💡 Technical Note: Operating at Layer 1 (Physical), hubs broadcast incoming data packets out to every connected port regardless of the intended recipient, leading to higher network traffic and collision domains. They are mostly obsolete today.

Firewalls

Firewalls are used to protect networks from unauthorized access by filtering incoming and outgoing network traffic.

💡 Technical Note: Can be implemented as software or hardware. They inspect packets based on pre-configured security rules, IP addresses, port numbers, and application-layer protocols.

Client computer

A Client computer is a networked device that uses the resources of a Network. Client computers are typically located on users’ desks and usually run a desktop version of Operating system. Such as Windows 7, vista, Windows 10 or can be a Linux or any desktop version of OS.

💡 Technical Note: Clients initiate requests to servers for services such as web browsing, email retrieval, or file access using client-server architecture models.

Server computer

Server is the device that serves to a network by running a Network Operating System (NOS) and maintaining and controlling the network functions. Server computers typically run a specialized network operating system such as Windows Server versions or some Linux server versions, along with special software to provide network services. A single server can perform many tasks. Server computers are very expensive Because of their hardware capabilities.

💡 Technical Note: Equipped with enterprise-grade hardware (redundant power supplies, ECC RAM, multi-core processors) to ensure high availability, fault tolerance, and simultaneous client handling.

Wireless Access Points

These devices enable devices to connect to the network wirelessly using Wi-Fi.

💡 Technical Note: Bridges wireless traffic onto the wired local area network (LAN), converting radio frequency signals into digital data frames.

Network-attached storage (NAS)

This is a type of storage device that is connected to the network and is accessible to other devices on the network.

💡 Technical Note: Operates as a file-level computer data storage server connected to a computer network, allowing multiple users and diverse clients to retrieve data from centralized disk capacity.

Different types of Computer Networks

2025-09-18T14:41:00.000-07:00

LAN (Local Area Network) is a network that connects computers and devices within a small geographical area such as a building, office, or campus. LANs are typically owned and maintained by a single organization and are used for sharing resources such as printers, files, and internet access.

MAN (Metropolitan Area Network) is a network that covers a larger geographical area than a LAN but smaller than a WAN. MANs are typically used by organizations that need to connect multiple LANs in different buildings or locations within a city or metropolitan area.

WAN (Wide Area Network) is a network that covers a large geographical area such as a country, a continent, or even the entire world. WANs are typically owned and maintained by telecommunication companies and are used for connecting geographically dispersed LANs and MANs.

WLAN (Wireless Local Area Network) is a type of LAN that uses wireless technology such as Wi-Fi to connect devices within a small geographical area. WLANs are commonly used in homes, offices, and public spaces such as airports and cafes.

Network Topologies - Bus topology

2025-09-17T15:08:00.000-07:00

A network topology is the physical layout of network. Basically the way all the nodes in the network are connected. There are several different types of network topologies, each with advantages and disadvantages. The different types of network topologies are Bus topology, Ring topology, Star topology and Mesh topology.

Bus topology

The first type of network topology is called a bus topology. A bus topology uses one cable to connect all of the nodes together. A bus topology is very easy to set up and requires no additional hardware. The cable is also called a backbone or trunk. The bus topology is probably the easiest one to understand and to implement. Bus topology networks use coaxial cable. Each end of each segment of the network has a special cable terminator on it, without which the network will not function.

Advantages of Bus Topology:

It’s easy to install and maintain.
It’s inexpensive to implement.
No additional hardware required, such as switches and hubs.
Less cabling is required than other topologies.

Disadvantages of Bus Topology:

One breakdown of cable is affect to the whole network.
Difficult to troubleshooting.
Data communication is slower than with some of the other topologies.

Network Topologies - Star topology

2025-09-15T15:14:00.000-07:00

The star network is a very common network topology. In a star topology, each network node is connected to a central device called a hub or a switch. Each workstation has a cable that goes from the network card to the central device. One of the major benefits of a star topology is that a break in the cable causes only the workstation that is connected to the cable to go down, not the entire network. Star topology networks can use one of several forms of Ethernet. The most common is 100Base-T Ethernet, which provides 100 Mbps of bandwidth.

Advantages of Star Topology:

It’s simple to implement and maintain.
It allows for direct communication between two nodes.
Scalability and ease of adding another system to the network.
It’s easy to troubleshoot.

Disadvantages of Star Topology:

The central device fails in a star topology, the entire network comes down.
Another disadvantage of a star topology is cost.
It’s requiring more cables.

Network Topologies - Ring topology

2013-09-16T15:11:00.007-07:00

A ring topology is actually not a physical arrangement of a network cable. Ring is a logical arrangement. In a ring topology, all nodes are connected via a cable that loops in a ring or circle. The Ring passes data logically from station to station until the data reaches its destination. Years ago, ring topologies were common in LANs, as three popular networking technologies used rings: ARCNET, Token Ring and fiber distributed data interface (FDDI) networks.

Advantages of Ring Topology:

It’s fairly simple to maintain.
Equal access for each node.
Signal degeneration is low.

Disadvantages of Ring Topology:

Any maintenance would affect all the nodes that connect to the ring.
Under normal traffic load, a ring is much slower than other topologies.
Isolating a problem can be difficult in some ring configurations.

Network Topologies - Mesh topology

2013-09-14T15:16:00.004-07:00

Mesh topology is a type of network topology where each device is connected to every other device in the network through a dedicated point-to-point link. This creates a redundant and fault-tolerant network where data can be transmitted through multiple paths. Mesh topology can be classified as full mesh or partial mesh depending on the number of direct links between devices. Full mesh topology is where every device is directly connected to every other device, while partial mesh topology is where some devices are directly connected to every other device and others are only connected to some devices.

Advantages of Mesh Topology:

High reliability and fault tolerance due to redundant paths.
High scalability as more devices can be added without affecting the performance.
No central point of failure as each device can act as a repeater to transmit data.
Better performance as data can be transmitted concurrently through multiple paths.

Disadvantages of Mesh Topology:

High cost as a large number of cables and network ports are required.
High complexity in design, installation, and maintenance.
Low efficiency due to the large amount of data transmission overhead.

What is a coaxial cable?

2013-08-31T04:19:00.017-07:00

A type of cable that was once popular for Ethernet networks is coaxial cable, sometimes called thinnet or BNC cable because of the type of connectors used on each end of the cable. It was the original cable used in Ethernet networks and is still used almost universally for television connections. There are two types of coax cabling: Thinnet and Thicknet. The two differ in thickness and maximum cable distance that the signal can travel.

Thinnet: Thin coaxial cabling, known as RG 58, (which is a flexible coaxial cable about ¼-inch thick.) is used for connections that use a low power signal. In Ethernet, the maximum distance that data can be transmitted Is 185 meters.

Thicknet: This coaxial cable, also known as RG-8, gets its name by being a thicker cable than thinnet. Thicknet cable is about ½-inch thick and is used for connections that require a higher power signal. The maximum travel distance between nodes using thick coaxial cables is 500 meters.

What is a Twisted Pair Cable?

2013-08-30T04:29:00.036-07:00

Twisted pair cabling gets its name by having four pairs of wires that are twisted to help reduce crosstalk or Electromagnetic interference from outside electrical devices. There are two forms of twisted pair cabling, unshielded twisted pair (UTP) and shielded twisted pair (STP).

Unshielded Twisted Pair (UTP)

The typical twisted pair cable for network use contains four pairs of wires. Each member of the pair of wires contained in the cable is twisted around the other. The twists in the wires help shield against electromagnetic interference. The maximum distance of UTP is 100 meters. UTP cabling typically has only an outer covering (jacket) consisting of some type of non-conducting material. UTP cabling seems to generate the lowest expectations of twisted-pair cable. Its great popularity is mostly due to the cost and ease of installation. With every new generation of UTP cable, network engineers think they have reached the limits of the UTP cable’s bandwidth and capabilities. However, cable manufacturers continue to extend its capabilities.

Shielded Twisted Pair (STP)

STP cabling is a type of copper cabling that is used in networks where fast data rates are required. STP cabling includes metal shielding over each individual pair of copper wires. This type of shielding protects cable from external EMI (electromagnetic interferences). STP cables are also referred to as Ethernet cables. STP cables provide additional protection to the internal copper, thus data rates are Increased and more reliable.

Cable categories

Twisted pair cable comes in various grades called categories. These categories are specified by the ANSI/EIA standard 568. (ANSI stands for American National Standards Institute; EIA stands for Electronic Industries Association.) The standards indicate the data capacity, also known as the bandwidth, of the cable. Although higher-category cables are more expensive than lower-category cables, the real cost of installing Ethernet cabling is the labor required to actually pull the cables through the walls.

What is a Fiber-optic Cable?

2013-08-29T04:39:00.009-07:00

Fiber-optic cables use optical fibers that carry digital data signals in the form of modulated pulses of light. Fiber optic cables are able to carry data for long distances. An optical fiber consists of an extremely thin cylinder of glass, called the core. The core is wrapped in a cladding, which is denser glass material that reflects light back to the core. Fiber optic cable has helped make a lot of the advances in networking over the last few years. The use of fiber cables provides for an increase in the distance data can travel between nodes, as well as speeds that are, well, as fast as light.

There are two types of fiber-optic cables: single-mode fiber (SMF) and multimode fiber (MMF).

Single-mode fiber:

SMF cables are thinner Than MMF cables. SMF uses a single ray of light, known as a mode, to carry the transmission over long distances. SMF cable is more reliable and supports a much higher bandwidth and longer distances than MMF cables.

Multimode fiber:

MMF cabling is made for shorter distances. MMF Uses multiple rays of light simultaneously, with each ray of light running at a different reflection angle to carry the transmissions. So the distance and Speed are less.

Fiber-optic cable supports up to 1000 stations and can carry the signal up to and beyond 2 kilometers. Fiber-optic cables are also highly secure from outside interference, such as radio transmitters, arc welders, fluorescent lights, and other sources of electrical noise.

UTP ජාල කේබලයක් (Network Cable) නිවැරදිව සකස් කිරීම

2013-08-28T09:35:00.000-07:00

Module: Setup and Maintain Network Systems

Task: Terminate a UTP Cable Using RJ45 Connectors

අරමුණු

මෙම ක්‍රියාකාරකම අවසන් වන විට ඔබට,

✓ ජාල කේබල් සකස් කිරීමට අවශ්‍ය මෙවලම් හා ද්‍රව්‍ය හඳුනාගත හැකි විය යුතුය.
✓ UTP කේබලයක් නිවැරදිව සූදානම් කළ හැකි විය යුතුය.
✓ T568A සහ T568B වර්ණ සම්මතයන් අනුව වයර් පිළිවෙළ සකස් කළ හැකි විය යුතුය.
✓ RJ45 සම්බන්ධකයක් නිවැරදිව ක්‍රිම්ප් (Crimp) කළ හැකි විය යුතුය.
✓ සකස් කළ කේබලය පරීක්ෂා කර දෝෂ හඳුනාගත හැකි විය යුතුය.

අවශ්‍ය ද්‍රව්‍ය හා මෙවලම්

ද්‍රව්‍ය

UTP කේබලයක් (Cat5e / Cat6)
RJ45 සම්බන්ධක 2 ක්

මෙවලම්

Crimping Tool
Wire Cutter
Cable Stripper
Network Cable Tester

ආරක්ෂක උපදෙස්

✓ Crimping Tool භාවිතයේදී ප්‍රවේශම් වන්න.

✓ කැඩුණු හෝ හානි වූ RJ45 සම්බන්ධක භාවිතා නොකරන්න.

✓ කේබලය අධික ලෙස නැමීමෙන් වළකින්න.

✓ අත් වියළිව තිබෙන බව තහවුරු කරගන්න.

✓ වැඩබිම පිරිසිදුව හා පිළිවෙලට තබාගන්න.

T568A හා T568B වර්ණ සම්මත

T568A

Pin	වර්ණය
1	සුදු/කොළ
2	කොළ
3	සුදු/තැඹිලි
4	නිල්
5	සුදු/නිල්
6	තැඹිලි
7	සුදු/දුඹුරු
8	දුඹුරු

T568B (බහුලව භාවිතා වන සම්මතය)

Pin	වර්ණය
1	සුදු/තැඹිලි
2	තැඹිලි
3	සුදු/කොළ
4	නිල්
5	සුදු/නිල්
6	කොළ
7	සුදු/දුඹුරු
8	දුඹුරු

ක්‍රියා පටිපාටිය

පියවර 1 - කේබලය මැන කපාගන්න

අවශ්‍ය කේබල් දිග තීරණය කරන්න.
අමතරව සෙන්ටිමීටර් 10 ක් පමණ තබාගන්න.
Cable Cutter භාවිතයෙන් කේබලය කපාගන්න.

පරීක්ෂා කරන්න

☐ කේබලයේ දිග නිවැරදිද?

☐ කැපුම සෘජුව තිබේද?

පියවර 2 - පිටත ආවරණය ඉවත් කරන්න

කේබලය Stripper හෝ Crimping Tool හි Stripping කොටසට දමන්න.
මෘදු ලෙස වට කරකවන්න.
මි.මී. 25 ක් (අඟලක් පමණ) පමණ පිටත ආවරණය ඉවත් කරන්න.

වැදගත්

⚠ ඇතුළත වයර්වල ආවරණය කැපී නොයන ලෙස සැලකිලිමත් වන්න.

පරීක්ෂා කරන්න

☐ වයර් 8 ම සම්පූර්ණද?

☐ හානි වී නොමැතිද?

පියවර 3 - වයර් යුගල වෙන් කරන්න

UTP කේබලයේ වර්ණ යුගල 4 ක් ඇත.

තැඹිලි යුගලය
කොළ යුගලය
නිල් යුගලය
දුඹුරු යුගලය

අවශ්‍ය ප්‍රමාණයට පමණක් යුගල ලිහාගන්න.
වයර් සෘජු කරන්න.

වැදගත්

⚠ අධික ලෙස යුගල ලිහාගැනීම කේබලයේ කාර්යසාධනය අඩු කරයි.

පියවර 4 - වයර් නිවැරදි අනුපිළිවෙළට සකස් කරන්න

මෙම පුහුණුව සඳහා T568B සම්මතය භාවිතා කරන්න.

වම් සිට දකුණට වර්ණ අනුපිළිවෙළ:

Pin	වර්ණය
1	සුදු/තැඹිලි
2	තැඹිලි
3	සුදු/කොළ
4	නිල්
5	සුදු/නිල්
6	කොළ
7	සුදු/දුඹුරු
8	දුඹුරු

පහත පරිදි ක්‍රියා කරන්න

වයර් ඇඟිලි අතර රඳවා ගන්න.
wire සෘජු කරන්න. (එතුනු ස්වභාවය නැති කර ගන්න)
නිවැරදි අනුපිළිවෙළට තබන්න.
වර්ණ අනුපිළිවෙළ නැවත පරීක්ෂා කරන්න.

පරීක්ෂා කරන්න

☐ වර්ණ අනුපිළිවෙළ නිවැරදිද?

☐ වයර් සෘජුව තිබේද?

☐ වයර් මාරු වී නොමැතිද? 😂

පියවර 5 - වයර් කපා සමාන කරන්න

වයර් තදින් අල්ලා ගන්න.
සියලුම වයර් එකම දිගට කපාගන්න.
මි.මී. 12 - 13 ක් පමණ ඉතිරි කරන්න.

වැදගත්

⚠ සියලුම වයර් එකම දිගට තිබිය යුතුය.

පරීක්ෂා කරන්න

☐ සියලු වයර් සමාන දිගින් තිබේද?

පියවර 6 - RJ45 සම්බන්ධකයට වයර් ඇතුල් කරන්න

RJ45 සම්බන්ධකය අල්ලාගන්න.
- ක්ලිප් කොටස පහළට
- රන් පාට Pin ඉහළට
වයර් ඇතුල් කරන්න.
සම්පූර්ණයෙන්ම තල්ලු කරන්න.

පහත දේ තහවුරු කරන්න

☐ වයර් 8 ම ඉදිරිපසට ළඟා වී තිබේද?

☐ වර්ණ අනුපිළිවෙළ වෙනස් වී නැද්ද?

☐ කේබලයේ පිටත ආවරණය RJ45 තුළට ඇතුල් වී තිබේද?

පියවර 7 - Crimp කිරීම

RJ45 සම්බන්ධකය Crimping Tool එකට දමන්න.
Handle එක සම්පූර්ණයෙන්ම තද කරන්න.
ඉවත් කර පරීක්ෂා කරන්න.

Crimp කිරීමේදී සිදුවන දේ

RJ45 Pin මඟින් වයර් ආවරණය සිදුරු කරයි.
විද්‍යුත් සම්බන්ධතාවය ඇති කරයි.
Strain Relief මඟින් කේබලය අල්ලා තබයි.

පරීක්ෂා කරන්න

☐ RJ45 සම්බන්ධකය තදින් සවි වී තිබේද?

☐ වයර් ලිහිල් නොවී තිබේද?

පියවර 8 - අනෙක් කෙළවර සකස් කරන්න

Straight Through Cable

කෙළවර දෙකම T568B භාවිතා කරන්න.

භාවිතය:

Computer → Switch
Computer → Router
Printer → Switch

Crossover Cable

එක් කෙළවරක්	අනෙක් කෙළවර
T568A	T568B

භාවිතය:

පැරණි Computer-to-Computer සම්බන්ධතා සඳහා

පියවර 9 - Cable Tester මඟින් පරීක්ෂා කරන්න

එක් කෙළවර Main Unit එකට සම්බන්ධ කරන්න.
අනෙක් කෙළවර Remote Unit එකට සම්බන්ධ කරන්න.
Tester එක ON කරන්න.

නිවැරදි ප්‍රතිඵලය

LED අනුපිළිවෙළ:

1 → 2 → 3 → 4 → 5 → 6 → 7 → 8

දෝෂ හඳුනාගැනීම

දෝෂය	හේතුව
LED එකක් නොදැල්වීම	වයර් කැඩී ඇත
වැරදි අනුපිළිවෙළ	වර්ණ අනුපිළිවෙළ වැරදියි
Pin එකක් නොපෙනීම	Crimp කිරීම දුර්වලයි
LEDs කිහිපයක් එකවර දැල්වීම	Short Circuit

අවසාන පරීක්ෂණ ලැයිස්තුව

අයිතමය	✓
කේබල් දිග නිවැරදියි	☐
වයර් හානි වී නොමැත	☐
T568B අනුපිළිවෙළ නිවැරදියි	☐
වයර් සමාන දිගින් ඇත	☐
RJ45 තුළ සම්පූර්ණයෙන් ඇතුල් කර ඇත	☐
පිටත ආවරණය RJ45 තුළ ඇත	☐
Crimp කිරීම නිවැරදියි	☐
Cable Tester පරීක්ෂාව සමත්	☐

සාමාන්‍ය වැරදි

❌ වර්ණ අනුපිළිවෙළ වැරදීම.

❌ වයර් අධික ලෙස ලිහා ගැනීම.

❌ වයර් අසමාන දිගින් කැපීම.

❌ කේබල් ආවරණය RJ45 තුළට නොයැවීම.

❌ සම්පූර්ණයෙන් Crimp නොකිරීම.

❌ පරීක්ෂා නොකර භාවිතයට ගැනීම.