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Network Fundamentals: Top Picks

Network Fundamentals
Power over Ethernet (PoE) was invented by PowerDsine back in 1997 and the first power injector (Midspan) was installed in 1998! Many manufacturespart…
Network Fundamentals
A Denial of Service (DoS) attack is a malicious attempt to disrupt the normal functioning of a website, server or network by flooding it with traffic…
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
Measuring network performance has always been a difficult and unclear task, mainly because most engineers and administrators are unsure which approac…

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
SNMP (Simple Network Management Protocol) and Netflow are both popular protocols with admins, prized for their ability to give visibility over the ne…
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…

Network Protocols:

Subnetting
When we subnet a network, we basically split it into smaller networks. For example, when a set of IP Addresses is given to a company, e.g 254 they mi…
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…
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…
Domain Name System (DNS)
This section will deal with the analysis of the DNS packets by examining how DNS messages are formatted and the options and variables they contain. T…
TCP - UDP Protocol Analysis
This article covers the UDP protocol. We examine the structure of the UDP header, the protocols that use UDP as a transport plus a lot more. Some co…
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
The TCP Options (MSS, Window Scaling, Selective Acknowledgements, Timestamps, Nop) are located at the end of the TCP Header which is also why they ar…
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…

STP/ICMP Protocols:

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…
Spanning Tree Protocol (STP)
Spanning Tree Protocol, Rapid STP port costs and port states are an essential part of the STP algorithm that affect how STP decides to forward or blo…
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
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…

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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…
VLAN Networks
We hear about them everywhere, vendors around the world are constantly trying to push them into every type of network and as a result, the Local Area Netw…
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
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…

Routing
We all understand that TCP/IP, IPX-SPX are protocols which are used in a Local Area Network (LAN) so computers can communicate between with each other and…
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
Hybrid routing protocols are a combination of distance-vector and link-state routing protocols, and are used to provide a more efficient and scalabl…
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
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…
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
Static NAT (also called inbound mapping) is the first mode we're going to talk about and also happens to be the most uncommon between smaller networks. S…