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Articles:
The OSI Model: Layer 5 - Session Layer
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The OSI Model: Layer 4 - Transport Layer
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The OSI Model: Layer 3 - Network Layer
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The OSI Model: Layer 2 - Datalink Layer
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The OSI Model: Layer 1 - Physical Layer
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Suggested Articles:
802.3 Fast Ethernet (100 Mbit/Sec) Model
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The OSI Model: Layer 4 - Transport Layer
The Transport layer is responsible for providing mechanisms for multiplexing upper-layer application, session establishment, data transfer and tear d…
ICMP Protocol - Part 6: Redirect Messages
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…
TCP Header Anaylsis - Section 6: TCP Options
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…
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Netflow Articles:
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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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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: Monitor Bandwidth & Network Utilization…
Monitoring network traffic & bandwidth usage via Netflow is mandatory for any type and size network. Gaining visibility into user traffic, applic…
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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…
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…
VLANs - Access & Trunk Links
If you've read our previous article The VLAN Concept - Introduction to VLANs then you should feel comfortable with terms such as 'VLAN', 'Stati…
InterVLAN Routing - Routing between 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…
Link State Routing Protocols
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…
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IGRP (Interior Gateway Routing Protocol) is a Cisco proprietary distance-vector routing protocol used in enterprise networks to exchange routing informati…
Introduction to Routing Protocols
Distance Vector, Link State RIP, IGRP, EIGRP, OSPF
Routing protocols were created for routers. These protocols have been designed to allow the exchange…
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…