Author: Asad Ijaz

NetworkUstad's lead networking architect with CCIE certification. Specializes in CCNA exam preparation and enterprise network design. Authored 2,800+ technical guides on Cisco systems, BGP routing, and network security protocols since 2018. Picture this: I'm not just someone who writes about tech; I'm a certified expert in the field. I proudly hold the titles of Cisco Certified Network Professional (CCNP) and Cisco Certified Network Associate (CCNA). So, when I talk about networking, I'm not just whistling in the dark; I know my stuff! My website is like a treasure trove of knowledge. You'll find a plethora of articles and tutorials covering a wide range of topics related to networking and cybersecurity. It's not just a website; it's a learning hub for anyone who's eager to dive into the world of bits, bytes, and secure connections. And here's a fun fact: I'm not a lone wolf in this journey. I'm a proud member and Editor of Team NetworkUstad. Together, we're on a mission to empower people with the knowledge they need to navigate the digital landscape safely and effectively. So, if you're ready to embark on a tech-savvy adventure, stick around with me, Asad Ijaz Khattak. We're going to unravel the mysteries of technology, one article at a time!"

Router Packet Forwarding
CCNA June 9, 2019

How a Router Makes a Packet Forwarding Decision: A Step-by-Step Guide with Advanced Insights 2025

Routers are the traffic directors of the internet, guiding data packets to their destinations with precision. But how exactly do they decide where to send each packet? This guide’ll break down the router packet forwarding process, explore advanced concepts like Longest Prefix Match and Administrative Distance, and reveal how modern innovations like SDN (Software-Defined Networking) reshape routing. By the...
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Network diagram showing a host device, default gateway, and routing table directing data packets between subnets.
CCNA June 9, 2019

Host Default Gateway and Routing Table: The Ultimate Guide

When a host needs to communicate with another device on the network, it uses two critical components: the host’s default gateway and the routing table. This article explains how these elements work together to ensure packets reach their destinations. In 2025, the host default gateway’s role has expanded with 5G and IoT networks, where dynamic routing tables adapt...
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Host Forwarding Decisions: Computer host device determining data packet forwarding using subnet checks and a default gateway.
CCNA June 9, 2019

Host Forwarding Decisions: A Complete Guide to Packet Routing

In computer networking, every device—a laptop, server, or router—must decide how to forward data packets to their destinations. While routers specialize in forwarding traffic across networks, hosts (end devices like PCs) also make critical forwarding decisions using subnetting, routing tables, and protocols like ARP or IPv6 NDP. This article demystifies how hosts and routers make forwarding decisions, with...
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Detailed diagram of the IPv6 header structure highlighting key fields like Version, Traffic Class, Flow Label, and Next Header.
CCNA June 7, 2019

IPv6 Header and Fields – Exclusive Details

As we discussed earlier, IPv6 is the improved version of the internet protocol. The IPv6 header is one of the significant improvements over the IPv4 header. The header format has been dramatically simplified. Some header fields have been removed, and others have moved to the optional IPv6 Extension Header. The IPv6 header is only twice...
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IPv6 addresses structure visualised with hexadecimal notation and interconnected nodes symbolising modern networking.
CCNA June 7, 2019

Mastering IPv6 Addresses: Unlocking the Future of Networking in 2025

The IETF developed IPv6 addresses to overcome the limitations of IPv4, meeting current and future network demands. In 2025, its 128-bit address space addresses the global IP shortage. It is an excellent development with features that better suit current and future network demands. In 2025, IPv6 adoption has accelerated due to the global surge in...
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Limitations of IPv4 addresses depicted with a globe and diminishing IP symbols, highlighting networking limitations.
CCNA June 6, 2019

Limitations of IPv4: Challenges and Solutions in 2025

When the IPv4 address was invented, it was not expected that the Internet would become so popular that millions of devices would use these IP addresses. The IETF defined IPv4 addresses in RFC 791, published in 1981. The first design of IPv4 did not anticipate the Internet’s growth, which created many issues that proved that...
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Detailed IPv4 packet header diagram with labeled fields: Version, TTL, Protocol, Checksum, and Source/Destination IP addresses.
CCNA June 6, 2019

Mastering the IPv4 Packet Header: Insights for 2025 Networks

In 2025, the IPv4 packet header remains widely used despite IPv6 adoption, supporting legacy systems and critical applications like industrial IoT, where its compact structure is advantageous in constrained environments. The network layer converts transport layer segments into packets, with the IPv4 packet encapsulating the data unit and adding header information. In 2025, this process...
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connectionless
CCNA June 6, 2019

Mastering IP’s Connectionless Protocol: Insights for 2025 Networks

Connectionless No connection is established with the destination before sending data packets, defining a communication model where packets are sent without ensuring the recipient’s availability. This mirrors sending a letter without prior notice. In 2025, this efficiency supports real-time data in IoT, though retransmissions may increase with network congestion. Connectionless data communications work on the...
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OSI model diagram highlighting the network layer, with routers directing data packets and examples of IPv4/IPv6 addresses.
CCNA June 6, 2019

Mastering the Network Layer: Functions and Evolution in 2025

The primary function of the network layer is to deliver packets from source to destination across multiple networks. It also specifies the packet structure and processing used to carry the data from one host to another. The layer routes the packet through different channels to the other end and acts as a network controller. Analogy...
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Cisco switch ports with Ethernet cables, illustrating Auto-MDIX automatic cable detection for straight-through and crossover connections.
CCNA June 5, 2019

What is Auto-MDIX Cisco? – Everything to Know

Auto-MDIX (Automatic Medium-Dependent Interface Crossover) is a feature supported on Cisco switches and routers that automatically detects and configures the required cable type (straight-through or crossover) for Ethernet connections. This eliminates the need for network administrators to select or use specific cables when connecting devices manually. Historical Context In the past, connecting two network devices...
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