Interconnecting Cisco Networking Devices Pt. 1

ICND1 100-105

ICND1/CCENT 100-105 Course & Exam

Before we can dive into the details of ICND1, we have to build our foundations. Think about building a building. What do we do? We start with the foundation. We make sure we pour the concrete to support the rest of the building that we will be producing. We have to do the same thing here. We have to identify all those different components and how we will connect them together. And most importantly, we have to understand how communication flows from one end of the network to the other end.

Take a moment to think about all the electronic devices that you have access to, whether it's your phone or whether it's your television or whether it's your PC. What do they all have in common? Different components that make them work. But those components are nothing without one thing, and one thing that's very important, and that is the operating system. When we think about our switches and routers in the Cisco world, we just have a bunch of components inside of the box, what makes that box tick is that operating system, so we will focus on Cisco IOS.

Every electronic device we purchase will have some initial configuration on it. Now is that the initial configuration we will use in the real world? No, we won't. We always want to make those modifications to make that device meet our needs. And this is what we need to do here as well with our switches. We need to ensure that it has the most appropriate host name we can manage it across remote networks. We don't always want to have to connect to the other console cord. So we want to specify management IP address so we can connect to it. We also want to be able to double check to make sure that the boot up sequence is correct, that everything is working properly on our switch.

Do you remember which layer of OSI model or the TCP/IP stack we find our switches? Hope you are saying layer 2. So we find our switches at layer 2, but how do we connect all these switches together? What are we going to use at the physical layer of the OSI model? We need cables. There are different types of cables we can utilize. It's important that we choose the correct ones for our needs. So we will spend our time at layer 1 and layer 2 of the OSI model focusing on encapsulation methods, we could utilize to ensure that we have communication between our devices in our local area networks.

When is Internet Protocol version 4, or IPv4, going away? Who knows! Internet Protocol version 6, or IPv6, is definitely its replacement. But when will that happen? There is no set date, there is no light switch that will be turned on or off that says: "Oh everybody, go to IPv6." This is not going to happen. Even though we know that Internet Protocol version 6, or IPv6, is on the horizon, we still need to be proficient with IPv4 – addressing and subnetting. Will you take one large address block and just associate it with one portion of your network or will you be creative and be efficient with those IPv4 addresses because they are scarce and make sure that you separate them into their different logical networks, break them up through subnetting. If you are not familiar how to do that, we're going to teach you how to do that later in the course. We will examine how we can take a classful network /8, /16, /24, and subnet it. So let's say we use /24 and we subnetted it to /28, is that it? Can we no longer subnet it anymore? No we can, and this is known as variable-length subnet masking, or VLSM, and what is it? It's really just us subnetting a subnet.

After we've focused on layer 1 of the OSI model, layer 2, layer 3, let's keep moving on up. Let's focus on layer 4 of the OSI model, which is also known as the transport layer. And if we equate that to the TCP/IP stack, it's also referred to as the transport layer. Two protocols we will focus on specifically here, TCP and User Datagram Protocol, or UDP, we will compare and contrast them and we will learn when and why we use each of them for transportation. And then we will dive into something we have all been waiting for, the operation of our router. We will look at how our routers come to us in the box, how we will set them up, configure them and the basic operations of them.

Then we are going to cover one of the most important concepts here! We are going to discuss packet forwarding. How do we send that packet from one end station all the way to another end station that's in a completely different network? So we are digging into our router now. And we are going to focus on what happens when that packet arrives at the router, what it is going to do in order to make sure that it continues on its journey to its destination. We will have to focus on something else as well, that is the concept of routing and how we train our routers. So here, we will introduce you to static routing and how we can manually train our routers to ensure that they know what to do when the packet arrives.

Later on we are going to focus on access control list a few different times here in the ICND1, why are we doing that? Well there are 2 different ways how we can utilize access controllers, we can utilize them for classification and we can utilize them for filtering. Here we will focus on classification techniques, so that way there when we discuss Network Address Translation, or NAT, we understand why we utilize access control list to identify that traffic that will be translated using NAT.

So you just received your new router and switch, you open the box, pull them out, set them all up. Is there any security set up by default on your routers and switches, what do you think? The answer is no, there is no security. We have to spend the time to set these devices up and harden them to make sure that they are protected from attacks, attacks from users inside of our network as well as the attacks from users outside of our network. Switches and routers are designed to forward traffic, so we have to make sure that the traffic that's being forwarded is not hindered in any way, shape, or form because of some type of security breach.

Our networks will contain many different switches. It will also contain many different routers. What does that mean to us? That means that, we are going to have many different subnets. And we are going to scale our network, we are going to grow, we don't want our network to stay small. If our network stays small, that means we are not expanding, we are not growing, so as we will scale our networks and we will grow. We are going to have to be little more diligent and make sure that we design our networks appropriately to make sure that we control the flow of traffic. If the traffic is not flowing properly, things will get congested in our network. So we need to understand the concept of Virtual Local Area Networks, or VLANs. VLANs give us the ability to segregate that layer 2 environment and give us the ability to ensure that we allow traffic to flow more efficiently. But now as our network scales, do we want to continue to hand out IP addresses statically, you know, the good old way to configure IP addresses manually on the PC's. No we don't want to do that, scaling means larger, meaning more work for us. So we want to rely on Dynamic Host Configuration Protocol, or DHCP, and we can, if we want, to set up our Cisco routers as DHCP servers.

As we continue to scale, we will eventually move out of our geographic location. What does that mean? It means we are going to have remote sites, we are going to have teleworkers, we are going to have users who travel and end up staying in hotels. How will they connect back to the local network where all the resources are there that they need to connect to? We are going to focus on that here. We are going to discuss wide area networks, and how we can allow those users who are not in that same location that the resources are; can connect to those resources. But as we continue to grow in scale, we need to rely on different types of protocols to ensure that our routers learn about all those different destination networks that we have out there, and this is where we rely on dynamic routing protocols, specifically our focus will be on Open Shortest Path First, or OSPF.

The majority of us have been putting off IP version 6 for years. We have known about it, we know it's on its way, but we have been saying, I will learn it later. Well folks, here is the time you need to learn it. We can no longer wait, we can no longer push off IP version 6. So our focus will be on the features of IP version 6 and allowing you to build that foundation you need to understand why we need IP version 6 and how we'll implement it. So we will focus on the configuration as well the operations of IP version 6. But scalable networks, many routers, we need routing protocols. Are there routing protocols for IP version 6? Yes there are, we will introduce you to those routing protocols but we will discuss them in more details later under ICND2 track.

In the end don't forget to test your skills and knowledge with our 100-101 CCENT/ICND1 practice tests.