CompTIA Network+ Certification (2005 Objectives) Tutorials
Network Connectivity / Segments vs Subnets
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Subtitles of the Movie (CompTIA Network+ Certification (2005 Objectives) / Network Connectivity / Segments vs Subnets)
When dealing with our networks we might find in need for splitting that network up into several logical or physical components. The act of this is called partioning a network. Basically splitting it up into pieces that might have benefits such as manageability or might even offer some performance benefits as well. So we talk about the benefits of those segments and subnets as well as the draw backs. So let's take a look at a network segment. Let's first take a look at some of the layer that we have here. That is we have our very central connecting device as a switch with the sub connecting devices as hubs. We have our in clients or in users connecting to those hubs. Now let's talk about our network segment, there are actually three network segments here. Everything connected to this hub would be considered network segment number one. This individual computer by itself would be connected to network segment number two and then finally these hubs and the computers connected over here would be our third network segment. So you probably guess that the network segment would actually be defined at the port that the computers are connecting to on the switch. So let's talk about how data travels, how a traffic looks when it is happening on a segment. When one of these computers wants to communicate this is called as computer one. Computer one will send its data signal to the hub and when that hub receives the data signal since the hub is not a very intelligent device it will forward the traffic to all the ports. So computer two in this example would hear that traffic as well as would the port that the hub is plugged into on the switch. So since these computers can all see each others traffic they actually have to compete for network access .So that is what's kind of the fine which is called a contention domain. So a segment pretty much goes hand in hand with the contention domain. We also noticed that we have one computer that's all by itself down here. We call that computer three .So computer three has its own port on the switch which allows that computer to communicate without having to compete with other computers for network access. So by segmenting this computer out by itself we can improve the network performance significantly. Another thing you should know about hubs is that they can mostly communicate at 10 mega bits per second .When compared to 100 mega bit per second switch that's pretty slow .So by connecting all devices directly to a switch instead of a hub, individually segmenting them out and allowing them to have their higher data transfer rate without having to have that contention really makes for a good well looked network. Now when talking about segments, segments actually provide benefits as far as network performances are considered depending on how we arrange them .With subnets we see almost no performance gains at all. The only reason we use subnets is for manageability purposes. So in this example we were very large network. Network one is our main network. So it might belong to an entire company for example .Then we have sub networks. Sub network one and sub network two of the large network one. The reason this is important is because we just had one large network with let's say 30,000 users we cannot have keep track of which computers run which part of the network .So by splitting this up into small networks let's say we put network one for sub network one on the marketing side, sub network two on the managerial side we can actually look at the IP addresses with the network id's and be able to determine where they are located. The drawback of sub netting larger networks is that you lose the number of IP addresses where network id's and node id's that you have access to. So we end up taking away from some of our unique identifiers by adding these sub networks. So this is kind of review or segments are usually going to be defined as switch and depending on how we have they arranged we can gain some very good network performance and our subnets will be defined by routers and would be arranged for management purposes. Next we cover data transmission and how data moves on the network.
Tutorial Information
| Course: | CompTIA Network+ Certification (2005 Objectives) |
| Author: | Brad Causey |
| SKU: | 33608 |
| ISBN: | 1-932808-53-1 |
| Release Date: | 2005-03-22 |
| Duration: | 7 hrs / 97 lessons |
| Captions: | No |
| Compatibility: |
Vista/XP/2000, OS X, Linux QuickTime 7, Flash 8 |
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