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Network Fundamentals: Top Picks

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…
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
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
Power over Ethernet (PoE) was invented by PowerDsine back in 1997 and the first power injector (Midspan) was installed in 1998! Many manufacturespart…

Featured Subcategories:

Netflow Articles:

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
In this article, we explore the core principles of bandwidth management and examine how modern network monitoring technologies can assist in maintain…
Netflow
This article explores how machine learning (ML) and network flow telemetry can be used to establish behavioral baselines, detect anomalous asset acti…
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…

Network Protocols:

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…
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…
Subnetting
This free online Subnet Calculator provides a fast and easy way to calculate all aspects of any IP Address and Subnet Mask. Simply enter your desir…
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 is an introduction to the 7-page TCP Header analysis section that follows. We briefly view each section of the TCP Header and then move…
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
This article shows the TCP Header and Segment. We explain where the TCP Header and Segment are located in an Ethernet frame and also briefly view the…
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…

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)
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 - 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…
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…

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VLAN Networks
This article deals with the popular topic of InterVLAN routing, which is used to allow routing & communication between VLAN networks. Our article anal…
VLAN Networks
VTP (VLAN Trunking Protocol) pruning is a feature that is used in Cisco switches to reduce unnecessary traffic in VLAN (Virtual Local Area Network) trunks…
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
VLANs are usually created by the network administrator, assigning each port of every switch to a VLAN. Depending on the network infrastructure and securit…

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
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
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 article explains how OSPF uses Link State Advertisement (LSA) to exchange information about the network topology between routers. When a router recei…

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…
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
The previous page (Static NAT - Part 1) helped us understand what exactly happens with Static NAT and how it works, and we saw a few examples of how to us…