Design
How a Broadcast Address Works
Imagine you’re Paul Revere, riding from Boston to Lexington to warn citizens that the redcoats were coming. He may not be as fast as computer networks today, but Paul Revere was essentially acting much like a broadcast would- he was relaying his message to the entire town of Lexington.
A broadcast, in particular, is a simple [...]
An Introduction to Dynamic Host Configuration Protocol
Let’s imagine you’re a system administrator at a large company. You are implementing a new network of several hundred computers. All is fine and well until you realize: you have to manually input every single IP address, subnet mask, and gateway settings onto every single computer. You’re paid well, but maybe not that well.
For those [...]
An Introduction to Ethernet Switching
When you stop to think how well the internet is put together, you start to wonder how the internet coexists with all the chaos that results from broadcasts, data collision, and data loops. Yet, despite the odds, the internet is still (currently) alive and thriving today. But what can we attribute this achievement to? As [...]
31Jan2008 | admin | 3 comments | Continued
A Brief Overview of Ethernet History
Perhaps some of the most tedious Cisco course material is on the history of Ethernet. Cisco itself claims that there isn’t a strong significance of the material in their courses- but rather it is good for getting a better sense of knowing strengths and weaknesses of Ethernet types.
Legacy Ethernet (10-Mbps) – 10BASE5, 10BASE2, and 10BASE-T
The [...]
Carrier Sense Multiple Access Collision Detect (CSMA/CD) Explained
First thing is first: save yourself some trouble and remember that carrier sense multiple access collision detect is best referred to as simply CSMA/CD. We’ve heard some ridiculously long terms before, but CSMA/CD takes the cake.
Jokes aside, this media-access mechanism is what keeps networks running. If two or more computers transmit data at the [...]
The Basics of Network Cable Testing
If 90% of all problems in a network are on the Physical Layer, then it isn’t any surprise that cable testing has become quite important in the industry. And although it may sound simple to test a pair of cables for faults, actually troubleshooting wire maps, crosstalk, propagation delay, or insertion loss can be more [...]
27Jan2008 | admin | 1 comment | Continued
The Difference Between Straight Through, Crossover, And Rollover Cables
There are generally three main types of networking cables: straight-through, crossover, and rollover cables. Each cable type has a distinct use, and should not be used in place of another. So how do you know which cable to use for what you need?
The Purpose of Straight-Through Cables
Straight-through cables get their name from how they are [...]
How to Subnet a Network
A properly designed subnet can do wonders for the security and performance of a network. The main idea in subnetting is to divide a network into smaller pieces, which we call subnets. Actually implementing a subnet is typically more difficult than simply using the default subnet mask of 255.255.255.0. This usually means that temporary or [...]
27Jan2008 | admin | 21 comments | Continued
A Guide to Bandwidth and Throughput
Bandwidth and throughput are two networking concepts that are commonly misunderstood. System administrators regularly use these two concepts to help plan, design, and build new networks. Networking exams also include a few bandwidth and throughput questions, so brushing up on these two subjects is a good idea before exam day.
What is Bandwidth?
You probably already have [...]
A Guide To Network Math
You are probably accustomed to using what is called decimal- the numbering system you’ve been learning since kindergarten. In networking we use three primary numbering systems: binary, decimal, and hexadecimal. It is direly important to know what each numbering system is for, and more specifically how to convert from one system to another. But don’t [...]
27Jan2008 | admin | 2 comments | Continued
