Recommended Ethernet Specifications for LANs

Cisco requires that students become familiar with the difference between Ethernet 10BASE-T, Fast Ethernet, and Gigabit Ethernet. You must know when to use each when cabling at the end-user level, workgroup level, and backbone level.

Note that backbone cabling (cable running from network to network) needs higher performance, since it is the part of a network that gets the heaviest traffic. End-users don’t need as much bandwidth, since not as much traffic is being directed. Although one could argue more is better, you will generally see that more is also increasingly expensive.

Peer-to- Peer Networks and Client/Server Networks

When we cable a LAN, there are two networking models we follow: peer-to-peer and client/server. Each model has its benefits and drawbacks, of which networking students are required to know.

The more popular of the two, client/server, makes use of a server. This server is simply a machine that performs requests for computers on the network. It might handle print requests, store information, or send email for computers on the network.

Whereas the client/server model has a central point of authority, the peer-to-peer model functions without any certain authority. Instead of the server, we have the lot of networked computers. As you can probably tell, this can easily lead to security risks, instability, and they certainly don’t scale well as networks grow in size.

In general, there are a few things that Cisco demands students remember about these two models.

Things to Remember with P2P and Client/Server Networking Models

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• 1. Peer-to-peer models are much easier to install, as compared to the client/server model
• 2. Peer-to-peer models don’t scale well- meaning as your network grows, you’ll be in a predicament to keep resources stable. The client/server model scales much more easily.
• 3. Peer-to-peer models don’t require any extra hardware- just network a few computers and you’re up and running. The client/server model will obviously cost a bit more to maintain.
• 4. Client/server models are centralized- meaning a single administrator can grant or deny rights to certain content with ease. This can be done with peer-to-peer networks, but with much more difficulty. Peer-to-peer networks can easily become quite unsecure as a result.

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The Basics of WAN Theory

A WAN, or wide area network, simply links between routers and switches. The internet, for instance, is the biggest WAN in existence. LANs and WANs not only differ from what they are used for, but how they are created. Instead of the common UTP or STP media, we’ll instead use a serial connection.

There are two sides to a serial cable: the DCE and DTE. The data communications equipment, or DCE, is considered to be the provider- and thus, a clocking rate needs to be set on the router that receives this end. The data terminal equipment, or DTE, is considered the client- and should not be set with a clocking rate. This clocking rate will ensure that bits are transferred in a synchronized order.

Note that one of the most common mistakes when connecting serial cables is confusing the DCE and DTE ends. Often, they aren’t labeled. The DCE side will be the “female” side, while the DTE side is “male.” Keep in mind that if the clocking rate is set on the DTE side instead of the DCE, the connection will fail.

Don’t worry if this seems unfamiliar to you- right now, all we need to know is that DCE is the provider and needs a clocking rate set- while the DTE is the client. We’ll cover these topics again when we delve into router configuration.

Closing Comments

Luckily, this is all you need to know about configuration of LAN and WANs at this point in time. You’ll notice that this material corresponds to the CCNA 1 Module 5 exam. If you are indeed a Cisco networking student, be sure to bookmark this content for future reference.

What is a LAN?

If you aren’t already familiar with a LAN, it is defined as a local area network. From the term local, you’d probably guess that LAN network designs don’t span a large region (and you’d be correct). The basic LAN is just a simple network of computers, although LANs can often span multiple buildings. In the example below, you can see a network divided by a router, which is being used to connect the network to the internet.

In general there are three things to remember about a LAN:

Three Things to Remember about LANs

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• 1. They operate within a limited geographical area
• 2. They allow a large amount of users to access media with high-bandwidth capability
• 3. They prove full-time connectivity with local services

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A LAN is a fairly easy concept to grasp- perhaps the simplest of all networks. In fact, computer networking started out with a simple LAN connection. Since the birth of the LAN, we have been graced with even more advanced technologies- such as the WAN.

The Difference between a LAN and a WAN

WANs are networks that interconnect LANs. You can think of it as a company who has offices in three separate states. If the company wishes to have each office on the same network, they would need to somehow connect the LANs together.

Whereas a WAN enables you to send an instant message to someone around the world, a LAN would be limited to a much smaller geographical location. You are actually more familiar with WANs than you think- you’re using one right now! The internet is biggest WAN on Earth. Looking at it from a global perspective, you can see a WAN as a collective of networks run by many people- whereas a LAN is often ran by a specific organization (and thus usually only has one administrator).

In general, there are three things to remember about WANs:

Three Things to Remember about WANs

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• 1. They operate using serial interfaces
• 2. They generally provide lower bandwidth compared to LANs
• 3. They provide full-time remote resources that are connected to local services

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Generally speaking, we could stop there. But we can further classify network designs even further with MANs and CANs.

What are MANs and CANs?

A MAN is short for metropolitan area network. As the name implies, it covers a metropolitan area- such as a city or the suburbs of a city. You can think of them as between what a LAN and WAN would be. They span a much larger geographical area than LANs, but do not often surpass the limits of a metropolitan area.

MANs are generally good for businesses and organizations that have multiple locations around a city. A bank may also take advantage of a MAN.

So, far so good, right? Well now we’ll introduce the CAN- the campus area network. You’ve probably guessed it- this type of network design spans a university or campus. It acts a lot like a MAN would in some cases, although it obviously has a much more specific purpose.

Thus far the deciding factor on how we classify network designs has been the area they cover. The black sheep of this convention is the SAN: noted (and named) for its functionality- not its coverage area.

What is a SAN?

A SAN stands for a storage-area network. It is a dedicated and high performance network that moves data between servers or other resources. The SAN is used to connect storage machines in a “farm” so that other parts of the network can take advantage of the storage space. You will commonly see a SAN connected to a LAN or WAN. In the below example, we are using the SAN to store information the web and email servers may need.

If you ever decide to start your own Fortune 500 business, your network will need to be very large in size. To help alleviate the strain on your network and stress from lack of disk space, a SAN will be all but necessary. Most SANs offer great disaster tolerance and scalability built in- something vital for keeping important company documents.

Other Types of Networks

Although you’d think we’ve just about covered it all, we can delve even deeper into network design. You may have heard of a WLAN, or a wireless local area network (which operates much like a LAN without cables). You might have also heard of a PAN- or a personal area network. These are usually used to describe small networks made between mobile devices such as phones. In the below example, you can see two devices connecting wirelessly- by Bluetooth, perhaps.

Although you can be as specific as you’d like, most networking exams only require you know the basics of LANs, WANs, MANs, and SANs. This may change in the future, so be sure to keep an open mind about the upcoming network designs. We did, after all, only start networking computers with simple LANs. Just years after, we have the many “AN”s that we just covered- and there’s no telling what we’ll have in the years to come.