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Network Fundamentals: Top Picks

Network Fundamentals
A network is simply a group of two or more Personal Computers linked together. Many types of networks exist, but the most common types of networks ar…
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
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…
Network Fundamentals
A long-long time ago (not long ago in earth time) 100 Mbps was THE technology. 100 Mbps uplinks bundled with ether-channel was the ultimate uplink te…

Featured Subcategories:

Netflow Articles:

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
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
Monitoring network traffic & bandwidth usage via Netflow is mandatory for any type and size network. Gaining visibility into user traffic, applic…
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:

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…
Domain Name System (DNS)
This section will help you understand how the DNS queries work on the Internet and your home network. There are two ways to use the domain name syste…
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…
TCP - UDP Protocol Analysis
As we have seen in the previous pages, some TCP segments carry data while others are simple acknowledgements for previously received data. The popula…
TCP - UDP Protocol Analysis
This section contains one of the most well-known fields in the TCP header, the Source and Destination port numbers. These fields are used to specify…
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…
Subnetting
There is always that day when you are called upon to provide a solution to a network problem. The number of problems that can occur in a network are…
IP Protocol
This article explains the 'Network-ID' and 'Host-ID' concept found in IP addressing and subnetting. We analyse the structure of IP addresses and netw…

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…
ICMP Protocol
The ICMP - Redirect Message is always sent from a gateway to the host and the example below will illustrate when this is used. Putting it simply (be…
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
The Internet Control Message Protocol (ICMP), is a very popular protocol and actually part of an Internet Protocol (IP) implementation. Because IP wa…

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VLAN Networks
The previous article introduced the VTP protocol, we examined how it can be used within a network, to help manage VLANs and ease the administrative overhe…
VLAN Networks
Dynamic VLANs were introduced to grant the flexibility and complexity(!) that Static VLANs did not provide. Dynamic VLANs are quite rare because of their…
VLAN Networks
Designing and building a network is not a simple job. VLANs are no exception to this rule, in fact they require a more sophisticated approach because of t…
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…

Routing
Routing Information Protocol (RIP) is a distance-vector routing protocol that is commonly used in small to medium-sized networks. It is one of the o…
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
This article explains how OSPF uses Link State Advertisement (LSA) to exchange information about the network topology between routers. When a router recei…
Routing
Our previous article explained the purpose of Link State Update (LSU) packets and examined the Link State Advertisement (LSA) information contained within…

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
Our previous article, Dynamic NAT - Part 1, covered the basic idea of Dynamic Network Address Translation. We are now going to take a closer look at the p…
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
Dynamic NAT is the second NAT mode we're going to talk about. Dynamic NAT, like Static NAT, is not that common in smaller networks but you'll find it used…