We wrote an article which covers Virtual Local Area Networks (VLANs) as a concept, and another article on configuring VLANs on Cisco witches. The remaining subject to cover is the different options that exist for routing between VLANs. Why do we need Routing Between VLANs? As we learned in a prior article, VLANs create a logical separation […]
Configuring VLANs on Cisco Switches
August 10, 2016 By 19 Comments
We’ve before written about VLANs and what they can do as a concept. This article will focus on configuring VLANs on Cisco switches. We will look at each command necessary to configure the topology below. If this topology looks familiar, it is because you saw it in the article which described how VLANs operated on […]
Virtual Local Area Networks (VLANs)
June 23, 2016 By 69 Comments
Virtual Local Area Networks, or VLANs, are a very simple concept that has been very poorly defined by the industry. This article will explain VLANs from a practical perspective. It will be framed around the two major functions of VLANs, and concluded with an explanation of the idea behind the Native VLAN. Finally, at the […]
EIGRP Feasibility Condition
April 11, 2016 By 4 Comments
EIGRP is a routing protocol whose strategy to prevent routing loops is based upon what is known as the EIGRP Feasibility Condition. EIGRP also makes use of another concept called Split Horizon, which we will also briefly touch on later in this article. To properly discuss the Feasibility Condition however, you must have an understanding […]
EIGRP Metric
April 8, 2016 By 14 Comments
The EIGRP Metric has caused confusion for many network engineers trying to understand the protocol. This article will dive into what the metric is, and how to boil it down into its simplified form. Formula and K-Values EIGRP is a Cisco Proprietary routing protocol created in the 1980s. As such, Cisco was the only vendor […]
EIGRP Terminology
April 7, 2016 By Leave a Comment
Anyone who has ever studied the EIGRP protocol has at some point or another been confused by the awkwardly defined terminology that is incorporated into the protocol. This article’s purpose will disambiguate all the EIGRP terminology that causes so much confusion when trying to understand the protocol. Terms that Describe Routes From the perspective of […]
Square and Multiply
March 9, 2016 By Leave a Comment
We’ve all done math problems that look like this: 35, 410, or N37. These are known as an exponentiation. And there is a trick to solving these problems with less calculations than simply multiplying the base number over and over again. That trick is known as the Square and Multiply method. Take 35. If doing that […]
Ethernet Wiring
December 8, 2015 By 31 Comments
Ethernet is a family of specifications that governs a few different things: It covers all the different wiring specifications (10BASE-T, 100BASE-TX, 1000BASE-T, etc…). It describes how to send bits (1s and 0s) across each wire. It also determines how to interpret those bits into meaningful frames. Initially, this article was meant to just cover the […]