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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
Unicast is a communication method used in computer networking where data is sent from a single sender to a specific destination device. In this…
Network Fundamentals
The first step in controlling broadcast and multicast traffic is to identify which devices are involved in a broadcast or multicast storm. The follow…
Network Fundamentals
In this section we are going to talk about the different ways a firewall can be set up. Depending on your needs, you can have a very simple firewall…

Featured Subcategories:

Netflow Articles:

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

Network Protocols:

Subnetting
Routing and Communication between subnets is the main topic here. This article analyses communications between subnets. We provide examples on differ…
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
The third field under close examination is the TCP Header length. There really isn't that much to say about the Header length other than to explain w…
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…
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…
TCP - UDP Protocol Analysis
Finally, the last page of our incredible TCP Analysis. As most of you would expect, this section is dedicated to the DATA section that follows the TC…
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…
Subnetting
So we have covered to some depth the subnetting topic, but there is still much to learn ! We are going to explain here the available subnet masks and…

STP/ICMP Protocols:

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)
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)
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 'ICMP Destination unreachable' message is quite interesting, because it doesn't actually contain one message, but infact six! This means that the…

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VLAN Networks
VLANs are usually created by the network administrator, assigning each port of every switch to a VLAN. Depending on the network infrastructure and securit…
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
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
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
This article explains how OSPF uses Link State Advertisement (LSA) to exchange information about the network topology between routers. When a router recei…
Routing
Distance Vector, Link State RIP, IGRP, EIGRP, OSPF Routing protocols were created for routers. These protocols have been designed to allow the exchange…
Routing
Open Shortest Path First (OSPF) is a popular routing protocol developed for Internet Protocol (IP) networks by the Interior Gateway Protocol (IGP) working…
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…

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…
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…