Sunday, February 24, 2008

PDN, Public Data Networks!


If you want to connect to someone from one of the States in America to another person in another country you can actually do that in two different ways. You can buy a PDN, a Public Data network. What a Public Data Network is , The providers takes care of the carrier, the routing services across the WAN, and the protocols. You deliver the data and the provider makes sure that the data gets to its destination.
What that actually means is that you send something over the network, and the provider just makes sure that it gets to the right place! The second option is to connect two distant offices to a contract carrier service. When you get involved with a contract carrier service they provide the hardware, but you have to deal with everything else, especially the routing issues!
Today we are going to talk about the grand daddy, big bad booty daddy. The server!
A server is a computer that provides shared resources to network users. A server is pretty much the computer that holds all of the data, that can be accessed by other computers that are connected to it. Now you can’t talk about a server unless you talk about the client. A client is a computer that access resources via the network on servers.

Here is a little example, a little tid bit that you can do, How to Share a folder.
This teaches you how to share a older on a Windows 95 workstation with share-level access control.
1. Open windows explorer by right-clicking on My Computer and selecting Explorer
2. Browse to the folder you want to share and right-click that folder.
3. Choose the option Sharing.
4. Select Shared as and enter a share name. Select the security level by clicking either Read-only, Full, or depends on Password.
5. Set a password for the chosen security level and click OK. If you do not set a password, anybody can access the folder with the given privilege.

Friday, February 22, 2008

Switched Networks, HUBS!


Today we are going to discuss some Switched Networks. They have become quite popular lately. HUBS are devices that connects networked devices to each other. The problem with Hubs is that once one of them opens up to communicate with another, it opens up the port. Making it unusable for other Hubs in the network. A switching Hub can help remedy this problem. See it turns on a switch so it can connect the two hubs directly, and the other HUBS don’t have to deal with their communications and can communicate with other HUBS.
Now we’ve already discussed about LAN’s today let’s move on to WANs.
Now try to remember what we talked about with LAN’s. You see your company is now growing, all of your computers in your building are connected under a LAN. Now say that your company has expanded to all parts of the world. Your company needs to contact all of these other branches now, and try to communicate with one another. What to do? What to do? Well you can always set up a WAN. Which stands for Wide Area Network. It’s the same thing as a LAN but it has a larger geographical area! There are many great advantages to WAN’s. It’s easier to communicate, share, and organize data with other branches all across the states!

Tuesday, February 19, 2008

Net + Lessons, Repeaters, Bridges, and Broadcast storms!


Well last time we discussed about Repeaters and Bridges, which were very simple concepts, but today we are going to into the disadvantages of the Bridges!
You see computers send out data packets without specific destination addresses, intended for all the computers it can reach. This is called a broadcast. A major disadvantage of bridge is that they don’t stop the broadcasts! Just think about a spam mailer, he lost his address book, so he just starts sending e-mails to EVERYONE on the internet! Since the broadcast packet doesn’t have a destination, the bridge has no other choice but to send it to everyone’s computer that is connected to the bridge. This can cause a BROADCAST STORM!!! Yeah it sounds scary, but that’s when the bridge sends the broadcasts to every segment on the network. It occurs when there are so many broadcast packets on the network that the capacity of the network bandwidth approaches or reaches saturation. The worst case scenario it can shut down the network!
Now that’s the professional definition of it, but try to take it apart and make it something simpler. Let’s say that you are making a smoothie, and you fill it up with loads of fruits and veggies. But then you start to overflow it, and now the blender won’t even start. You can use any other analogies that you want, as long as you understand the concept. TOO MUCH OF ANYTHING WILL SHUT IT DOWN!
The last thing that we will talk about today is the Routed Networks. See Routers are like the next step after the bridges. Bridges uses the destination MAC address, the Router uses the destination network address to see where a packet should go. Let’s pretend that the number of your house is your MAC, and the Network address is you street name. You can now see why using bridges can cause a broadcast storm right? You’d be sending all that information to anyone with the same numerical address as you. But with Routers it sends it to the STREET Address! Much more simpler.

Monday, February 18, 2008

Net + Lesson 2... Repeaters, and Bridges



Ok welcome back, last time we talked about LAN, but we never discussed any of the medians that are used to carry certain signals from computer to computer. Now if you think about it, when you send something through any network, does the signal stay strong forever. Think about it this way, when you drive your car down the east coast, say from New York, all the way down to Florida, is that car going to get you there on one tank of gas? Well I know we’ve had some breakthroughs with some hybrid cars, but the answer is no. You’d have to stop at a gas station and fill your car up with gas to make it more powerful, more energized wouldn’t you?
Same thing goes for signals, you see when networks first started out they were very small, it’s understandable because that’s how everything starts out, small. See early network cables had short maximum lengths, so a lot of the signals would become weakened. What could they do in order to re-energize the signal? Well Using a Repeater of course.
Repeater connects network cables by regenerating signals so they can travel on additional cable lengths. I think you understand this concept from the whole car driving example above! Computers on either side of the Repeater could access data on their computers as long as they were using the same media access design and the same protocol and transmission method. It means that if you were in your office, you could log into one computer, open up your desktop and see all of your files. Then you can log off, go to the next computer and log in the same way, and all of your files will be there!
But there is a disadvantage of the Repeaters. They simply pass on any data they receive to both segments that are attached to the device. What this means, is, Say you have 10 computers, and 10 workers. One person wants to send a file to just one other person, but the Repeater sends that file to everyone’s computer. Now imagine if each person on the network wanted to send one file to one other person, that would mean that over a thousand files would be sent over to everyone computer and it could easily flood the network! But there is a solution, and that will be the last thing that we talk about for the day. That solution to this problem is called a BRIDGE! The BRIDGE is just like the Repeater, but it can filter the data that it receives. A great invention, in order to stop the overflow of data going into the network! Study hard, and try to take what you don’t understand, and make it simple!

The Reboot of Net + Lessons. LESSON 1!


Ok, it’s been a while since I’ve been on here, but I’ve been busy learning, and memorizing a lot of information! So let’s restart everything, and since a lot of my old readers have left, we will try to get some new ones, we are going to start from the very very beginning!
All right, this is in no way shape or form a way of selling books online, this is just a guy, who is learning some computer stuff, and just helping out his fellow computer lovers out there! I heard that when you learn something you only retain so little of what you hear, but when you teach it to someone else, you’d retain about 50% of what your teaching or even more!

So let’s begin with the very first lesson!

What is a network? Hopefully everyone reading this should at least know what it means, even in the common sense, non computeristic way! Networking in the real world is to open one’s social circle and invite others into it, to discuss and communicate with one another! Networking that deals with computers is pretty much the same thing! A Network is two or more computers and their associated peripherals connected by a communication medium! Here is the jist of it.

Take two computers, and place them next to one another, are they going to share any information with each other? No they can’t talk, so what you have to do is use something to connect them to one another! See simple enough! All you need is something it connect them to one another!
Now we can start talking about LAN and WAN. LAN = Local Area Network, WAN = Wide Area Network.
I’m pretty sure that you can distinguish just exactly that means! If not then let’s discuss about LAN and WAN’s in some detail, but first we’ll go over the Local Area Network this time, and save WAN’s for later!
A LAN is a collection of computers that are connected in a geographically close network. What this means, is take for an example an office building. All of the computers are connected to one another. People can send their information from computer to computer, print from the same printer, do other things because they are all connected to one another in a small close area!
Study hard, and try to take what you don’t understand, and make it simple!

Monday, September 24, 2007

Net + Lesson 6

Well today I'm going to go back and discuss about Bus topologies, because it seems like a tough subject! Well not really. its a very easy and interesting concept to grasp in NET +. Just imagine a row of buses, it's as simple as that.

Today we are going to talk about Repeaters.
Have you ever had a signal go weak on you? Well I haven't really, had a signal go weak on me, but I bet it happens to people all the time!
Repeters Work on the physical layer of the OSI model! Repeaters pretty much make signals stronger! Simple, and easy to understand

Bridges and Routers

They provide a way of segmenting network traffic and connect different LAN types.

Now If you plan ahead, you can efficiently use Routers and create a great system in which you can have an incredible communications environment!

Thursday, September 20, 2007

Net + Lesson 5

What is... and Operations Manager? Do you know? Well? Come on out with it... Let me know what an Operations Manager is! Well I guess i can give a small explanation for the whole thing about Operation managers!

It's pretty much like a secret agent that you put into your computer, so it can monitor the computer!
It watches a lot of things on the computer, such as Windows Event log for alerts etc!
There are a few Versions of Operations Managers
- Microsoft Operations Manager 2000
- Microsoft Operations Manager 2005
- System Center Operations Manager 2007

Well I know it's a random topic about operations managers, but My teacher talked about it today, and this is actually the notes he gave me... so I'm posting it!

Today we are going to talk about the differences between Baseband vs. Broadband!
- The baseband transmision method uses the media so that the cable is taken up by a single transmission

- Broadband communications, the communicators use different frequencies to seperate their messages from others by using the same media at the same time!
More tomorrow... we'll talk about Half-duplex... full-duplex!