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Network Fundamentals: Top Picks

Network Fundamentals
A MAC address, or Media Access Control address, is a unique identifier assigned to a network interface controller (NIC) for use as a network addres…
Network Fundamentals
Network hubs were once the primary method of interconnecting network devices to create a local area network (LAN). Hubs were inexpensive, easy to ins…
Network Fundamentals
Network Switches are the evolution of Hubs and Repeaters, and enable the creation of networks by connecting multiple devices together. They are criti…
Network Fundamentals
Next-generation firewalls (NGFWs) and DMZ zones are two critical components of network security that work hand in hand to protect an organization's n…

Featured Subcategories:

Netflow Articles:

Netflow
Monitoring network traffic & bandwidth usage via Netflow is mandatory for any type and size network. Gaining visibility into user traffic, applic…
Netflow
In our previous article we explained how a Netflow Analyzer can help you gain visibility into your user traffic, application traffic and data flows w…
Netflow
This article will cover the basics of Netflow, including its use cases, Netflow supported devices, Netflow history, and variants. We’ll also dive int…
Netflow
SNMP (Simple Network Management Protocol) and Netflow are both popular protocols with admins, prized for their ability to give visibility over the ne…

Network Protocols:

Domain Name System (DNS)
The previous article covered the DNS Query message formats. In the article we analysed them in great detail and showed how various options are select…
IP Protocol
To understand the Internet Protocol, we need to learn and understand Binary. It is very important to know and understand Binary because part of the I…
Supernetting & CIDR
Supernetting is the opposite of of subnetting, and is also known as route aggregation or CIDR (Classless Inter-Domain Routing). Supernetting is a tec…
TCP - UDP Protocol Analysis
Understanding how each protocol fits into the OSI Model is essential for any network engineer. This page analyses how TCP is classified as a 'transpo…
Subnetting
There are a few different ways to approach subnetting and it can get confusing because of the complexity of some subnets and the flexibility they off…
IP Protocol
This article examines the Internet Protocol (IP) and its position within the OSI Model. We take a look at the IP Header and all fields contained with…
TCP - UDP Protocol Analysis
As previously mentioned on a number of occasions, TCP is one of the two protocols that lives at the Transport layer and is used to carry data from on…
Supernetting & CIDR
This articles build upon our previous pages covering  what is Supernetting (Route Summarization) & How Supernets Work and Supernetting In-De…

STP/ICMP Protocols:

Spanning Tree Protocol (STP)
One of the most used terms in network is LAN (Local Area Network). It’s a form of network that we encounter in our daily lives, at home, at work, stu…
Spanning Tree Protocol (STP)
In this article we will examine the Spanning Tree Bridge ID structure, explain why it has increments of 4096, how VLAN information is embedded (for P…
ICMP Protocol
As mentioned in the previous page, an Echo is simply what we networking engineers call a 'ping'. The Echo Reply is, as most would guess,  the 'p…
ICMP Protocol
The ICMP - Source Quench message is one that can be generated by either a gateway or host. You won't see any such message pop up on your workstation…

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VLAN Networks
Deciding whether to use ISL or IEEE 802.1q to power your trunk links can be quite confusing if you cannot identify the advantages and disadvantages of eac…
VLAN Networks
We mentioned that Trunk Links are designed to pass frames (packets) from all VLANs, allowing us to connect multiple switches together and independently co…
VLAN Networks
It's easy to see why virtual LANs have become extremely popular on networks of all sizes. In practical terms, multiple VLANs are pretty much the same as h…
VLAN Networks
While the VLAN Tagging article briefly covered the IEEE 802.1q protocol this article will continue building upon it by further analyzing the IEEE 802.1q T…

Routing
This article covers basic OSPF concepts and operation. We explain how OSPF works, how OSPF tables are built on an OSPF-enabled router and their purpose (N…
Routing
Link State routing protocols do not view networks in terms of adjacent routers and hop counts, but they build a comprehensive view of the overall network…
Routing
This is the third article of our OSPF series which analyzes the different OSPF States routers go through during the OSPF discovery and neighbor forming pr…
Routing
IGRP (Interior Gateway Routing Protocol) is a Cisco proprietary distance-vector routing protocol used in enterprise networks to exchange routing informati…

Network Address Translation - NAT
Before we dive into the deep waters of NAT, we need to make sure we understand exactly what NAT does. So let me give you the background of NAT, why it's h…
Network Address Translation - NAT
After that simple and informative introduction to the NAT concept, it's time to find out more about how it works and this is where the NAT table comes in…
Network Address Translation - NAT
In our previous article, Network Address Translation (NAT) Overload - Part 1, we explained what NAT Overload is and how it works. This page deals with the…
Network Address Translation - NAT
NAT Overload is the most common NAT method used throughout all networks that connect to the Internet. This is because of the way it functions and the limi…