Articles
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Articles:
The OSI Model: Layer 5 - Session Layer
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Articles:
The OSI Model: Layer 4 - Transport Layer
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Articles:
The OSI Model: Layer 3 - Network Layer
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The OSI Model: Layer 2 - Datalink Layer
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Articles:
The OSI Model: Layer 1 - Physical Layer
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Suggested Articles:
Domain Name System (DNS)
The DNS Protocol - Part 3: DNS Query Message Form…
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
TCP Header Anaylsis - Section 2: TCP Sequence & A…
This page will closely examine the Sequence and Acknowledgement numbers. The very purpose of their existence is related directly to the fact that the…
The OSI Model
The OSI Model: Layer 2 - Datalink Layer
The Datalink ensures that messages are delivered to the proper device and translates messages from the Network layer into bits for the Physical layer…
Ethernet Protocol, CSMA/CD, Collisions
Migrating From Ethernet To Fast Ethernet
In this article we will analyze the following aspects of upgrading/migrating from 10Mbit Ethernet to 100Mbit Ethernet.
Cabling
Incompatible Imple…
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Netflow Articles:
Bandwidth Detective: Uncover Hidden Traffic and E…
In this article, we explore the core principles of bandwidth management and examine how modern network monitoring technologies can assist in maintain…
NetFlow Analyzer: Free Download, Step-by-Step Ins…
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…
ML-Based Security Analytics in NetFlow Analyzer…
This article explores how machine learning (ML) and network flow telemetry can be used to establish behavioral baselines, detect anomalous asset acti…
Complete Guide to Netflow: How Netflow & its Comp…
This article will cover the basics of Netflow, including its use cases, Netflow supported devices, Netflow history, and variants. We’ll also dive int…
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VLAN Networks
VLAN Tagging - Understanding VLANs Ethernet Frames
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
Dynamic VLANs
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
VLAN Security - Making the Most of VLANs
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
VLANs - IEEE 802.1q Trunk Link Protocol Analysis
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
OSPF - Part 2: How OSPF Protocol Works & Basic Concept…
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
Distance Vector Routing Protocols
Distance Vector routing protocols use frequent broadcasts (255.255.255.255 or FF:FF:FF:FF) of their entire routing table every 30 sec. on all their interf…
Routing
OSPF - Part 6: OSPF LSA Types - Purpose and Function o…
Our previous article explained the purpose of Link State Update (LSU) packets and examined the Link State Advertisement (LSA) information contained within…
Routing
Routed Protocols
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…
Cisco Routers
Configuring Point-to-Point GRE VPN Tunnels - Unprotect…
Generic Routing Encapsulation (GRE) is a tunneling protocol developed by Cisco that allows the encapsulation of a wide variety of network layer protocols…
Cisco Wireless
Cisco Aironet 1100 & 1200 Series (1110, 1121, 1142, 12…
Resetting a Cisco Aironet access point can be required if you’ve lost your password or need to wipe out the configuration of a previously configured acces…
Cisco Switches
Resolving Cisco Switch & Router ‘DHCP Server Pool Exha…
In previous articles, we showed how it is possible to configure a Cisco router or Catalyst switch to provide DHCP server services to network clients. Ever…
Cisco Routers
MPLS Case Study: Why Route Summarization is not Recomm…
MPLS generates Implicit Null label (The Implicit NULL label is the label that has a value of 3) for directly connected interfaces and for the summary rout…





