CCNA R&S Certification Exam… a piece of cake…


It was the easiest test I’ve taken since I started preparing for the CCNA R&S Cert…

OK, maybe this comes across a bit arrogant, but that is not what I mean at all, let me explain.

I am not suggesting that the exam is easy, it is not. Anyone who is, or was preparing for a CCNA certification, needs to work hard at it because it is a well known fact that the exam is pretty demanding.
I mean, if you really prepared to pass the exam, and you do pass the exam… you know a lot about networking.

Continue reading CCNA R&S Certification Exam… a piece of cake…

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VLSM and Subnetting Practice.


On the last article, we mostly talked about Subnetting theory, however, subnetting is one of those topics which you don’t really understand until you practice, practice and… practice. I mean, you still need the theory of course, but you need just enough theory to get you started with the practice. While practicing, you are going to hear “click!” in your head… many times.

Continue reading VLSM and Subnetting Practice.

1.1 Purpose and functions of network devices: routers, switches, bridges and hubs.


We are going to start, slowly but surely, building a theoretical network in our minds. In order to do this, we are going to start from the beginning; recognizing all the components of a modern network as well as some not so modern devices. For now, it is going to be a basic description of each device’s function, but we will elaborate on each concept as we move forward. Let’s begin.

Continue reading 1.1 Purpose and functions of network devices: routers, switches, bridges and hubs.

Broadcast and Collision Domains.


Terms you need to understand.

Broadcast: In this case, a Data-Link layer (Layer 2) message sent to ALL devices attached to the same network segment.

Collision: When more then one device transmit data at the same time on shared media, the packets collide, data becomes corrupted and after a random period of time, devices have to re-transmit the data.

Broadcast Domain: All devices that a Broadcast message reaches at the Data -Link layer within a network is called a Broadcast domain. A network can have more then one Broadcast domain and a Broadcast domain is delimited by devices that stop Broadcast messages.

Collision Domain: Anywhere within a network where a Collision can occur. The limits of a Collision domain are marked by those devices that break up Collision Domains.

Continue reading Broadcast and Collision Domains.

IPv6 for future CCNAs (+), Final Part.


Unicast Addresses: Unique-Local.
Before we talk about Unique-Local Addresses (ULA), let me tell you about Site-Local addresses; it was deprecated in favor of the ULA back in 2004 because the term “site” was too ambiguous, no body agreed upon a clear definition of the term “site”; what was considered a “Site”?
Also, the provability of Site-Local address being globally unique were no that high, as opposed to ULAs.
ULAs are meant to be routed within an organization’s LAN or even WAN, but they are not routable over the public network (Internet), hence, you can think of ULAs very much as IPv4’s Private addresses.

Continue reading IPv6 for future CCNAs (+), Final Part.

IPv6 for future CCNAs – Part II


In IPv6 for future CCNAs – Part I, we ended the article talking, very lightly, about IPv6 address types. Let´s go ahead and dig deeper into the concepts.

To recap, the IPv6 address types are:

Unicast
One-to-one communication. Unique address assigned to an interface, a packet sent to a Unicast address will be received by one single interface. There are several types of Unicast addresses:

More…

IPv6 – for future CCNAs – Part I


The History:
So we are running out (have ran out?) of IPv4 addresses. They have been with us since the very beginning, they were there during the 1980`s when everything was calm, and they stuck by us during the chaotic growth of the Internet during the 1990`s. There were some rumors, during the 2000`s, that they were going to run out soon, but something called Classless Inter-Domain Routing (CIDR) and Network Address Translation/Port Address Translation (NAT/PAT) saved our butts… for a while.
These 4 little sets of numbers, called Octets, separated by dots were very mysterious, we used to look at them from the corner of our eyes asking our selves; What are they for?… What do they do?… How do they do it?
We were intimidated just by looking at them, and they were just 4 little sets of decimal numbers, numbers that we recognize, that we use every day in our daily lives.

Continue reading IPv6 – for future CCNAs – Part I