Posted on 22 February 2010. Tags: 12933, Bryant, ccie, CCNA, certification, chris, cisco, collision, cut, ethernet, exam, forward, fragment, free, icnd, intro, network, pass, router, segment, store, switch, through
To pass the CCNA exam and earn that coveted certification, you’ve got to know Cisco switches inside and out. Among the many important details you’ve got to know are the three methods that Cisco switches use to forward frames, and the differences between the three.
The first switching method is Store-and-Forward. The name is the recipe, because that’s just what the switch does – it stores the entire frame before beginning to forward it. This method allows for the greatest amount of error checking, since the Frame Check Sequence (FCS) can be run before the frame is forwarded. As always, there is a tradeoff, since this error checking process makes this the slowest of the three frame forwarding methods.
The quickest method is Cut-Through, where only the destination MAC address of the frame is examined before the forwarding process begins. This means that the part of the frame is actually being forwarded as it is still being received! The tradeoff here is that the FCS does not run, so there is absolutely no error checking with Cut-Through switching.
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Posted in Computer Certification
Posted on 03 February 2010. Tags: access, bri, CCNA, ccnp, crossover, dte/dce, ethernet, exam, frame, free, home, icnd, interface, intro, isdn, lab, loopback, network, pass, relay, router, serial, server, setup, simulator, switch, topology, tutorial
Part of your CCNA / CCNP education is deciding what network topology to use when you’re putting together your home lab. Some of you are starting with one or two routers or switches, while others are starting with more. A customer recently sent me a list of his Cisco routers and switches that he has available for a home lab and asked for my help in coming up with the best way to use them.
There is no “right” or “wrong” answer to this question; again, part of the learning process is configuring and reconfiguring the physical topology of your lab. Let’s look at the routers and switches he has available, including the interfaces on each, and come up with one possible CCNA / CCNP home lab setup.
The equipment list:
Two 3620 routers. Each has 1 serial port and 2 ethernet ports.
One 3640 router. This has two ethernet cards, each with two ports, and two AUI ports.
Three 2503s, my personal favorite for home labs! These have 1 AUI port, 2 serial interfaces, and one BRI interface apiece.
One 2524 router. This has one serial port, 1 ethernet port, and one BRI interface.
One 4500 router. This has eight BRI ports, 2 ethernet ports, and more importantly, four serial ports.
He also has a 5200 access server, an ISDN simulator, one 2924 switch, and one 1924 switch.
Now, if you don’t have this much equipment to work with, don’t panic! Most CCNA / CCNP candidates don’t; this is more of an exercise in looking at what you do have and using it to the utmost.
As I’ve mentioned in many of my CCNA / CCNP home lab articles, an access server is a great thing to have. All he needs is an octal cable to connect his AS to the other devices we choose to use, and he’s all set. (If you need an access server sample configuration, there is one on my website in the Home Lab section.)
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Posted in Computer Certification
Posted on 20 December 2009. Tags: desktop, keyboard, mice, network, networking, printer, speakers, wireless
We live in an age of technology and as such we are always looking for ways to make life easier or ways to make things look better. In the home or office (or even the home office) making things look better involves getting rid of clutter. This is where the wireless desktop comes into play. No wires means less clutter and because when using Bluetooth wireless devices line of sight is not needed, you can use your desk space to its optimum with no worries.
There is more to the wireless desktop than you might think as well. You will all be aware that you can get a wireless keyboard and mouse. But wireless technology and Bluetooth in particular stretches much further than that. Your mobile phone if a recent one will probably have Bluetooth technology built into it. This means that you can easily connect it to your PC. Companies such as Logitech offer software that really gets your mobile phone and your PC working together. Synchronization is just one aspect of this, but how about being able to type an SMS text message on your keyboard and send it without having to touch your phone. This is all possible with the power of Bluetooth. Communication with your mobile phone is not the only method of contact with Bluetooth. You can also get Bluetooth headsets that work with Microsoft Messenger so you can add an easy chat functionality to your desktop. As new products come on the market Bluetooth becomes more and more popular. Peripheral devices such as Printers and Scanners can now be found.
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Posted in Hardware
Posted on 18 October 2009. Tags: advantage, Bryant, CCNA, ccnp, certification, chris, cisco, exam, network, pass, plan, router, study, switch
Whether you’re just starting to think about passing the CCNA or CCNP exams, or you’ve been on the certification track for a while, you’ve got to have a plan for success. If you wanted to drive your car from Florida to California, you’d create a plan to get there. You’d get a map and decide how far you wanted to drive per day, and maybe even make some hotel reservations in advance. You certainly wouldn’t get in your car, just drive it randomly down the nearest highway, and hope you ended up in California, would you?
Certainly not. Earning your CCNA certification is the same way. It’s not enough to just study a few minutes “when you feel like it”, or tell yourself that you’ll start studying for the exams “when I get such-and-such done”. The perfect time to start on the road to Cisco certification is not tomorrow, and it’s not next week. It’s today.
You’re much better off with one hour of solid study than three hours of interrupted, unfocused study. Here are a few ways to go about getting the kind of quality study time that will get you to the CCNA or CCNP (or any Cisco certification, for that matter!).
Schedule your study time, and regard this study time as you would an appointment with a client. If you were to meet a customer at 10:00 to discuss a network install, would you just decide not to show up and watch television instead? Not if you wanted the job. The same goes for your study time. That’s an appointment with the most important customer of all – YOU.
Turn your cell, iPod, TV, instant messenger, and all other electronic collars off for the duration of your study time. I know those of us in information technology don’t like to say this, but we can actually exist without being in touch with the world for a little while. You may even get to like it! Having uninterrupted study time is key to CCNA and CCNP exam success.
Finally, schedule your exam before you start studying. Contrary to what many people think, “deadline” is not a dirty word. We do our best work when we have a deadline and a schedule to keep. Make out your study schedule, schedule your exam, and get to work just as you would a network project for a customer. The project you’re working on is your career and your life, and by following these simple steps you can make it a highly successful project – by passing your CCNA and CCNP exam!
Posted in Computer Certification
Posted on 11 September 2009. Tags: network, now, secrets, wireless
It is deniable that our works and lives are more convenient and easier when using wireless. We can work anywhere and that is why wireless networks are becoming so popular. Especially if you have broadband Internet access, a wireless router can give you instant communication with the world.
Imagine you are sitting by the pool and enjoying chatting through the Internet. Or lounging in the Jacuzzi listening to your MP3 collection is appealing to us all. Unfortunately, many, or even most, wireless units don’t come with security features already functioning. This may not seem like a big issue to someone who is simply setting up a home network, but there are a number of potential problems you should consider.
Identity theft seems to be the most serious problem. If your network is unsecured, the personal data on your wireless electronic equipment is also unsecured. The order you just placed for a book at Amazon may have given your contact and payment information to an unscrupulous hacker! Nearly every town in which “WiFi” is common will have “War Drivers” and “War Chalkers” at work. These are people who walk or drive around town with wireless equipment, searching for unsecured networks. The “Chalkers” then live up their name, marking curbs and other public items with chalk so that others can more easily find and exploit your network.
In fact, not all “War Drivers” are hackers, of course. Many just want to use your network for free, but the risk is high if you don’t learn how to protect yourself. You can usually find quite a bit of free information as to how to secure your network at the website of your router’s manufacturer, or by doing a search in a search engine for a phrase like “secure home wireless.”
In addition, there are also your neighbors who may find your network by accident and enjoy nosing into your activities and using your Internet access at will, slowing down your network speed in the process.
Even many businesses use cheap, home-use quality equipment for their company networks. With the poor security often found on small business networks, anyone with a basic knowledge of wireless can access sensitive company and customer data.
It is highly recommended that you hire service companies to secure your network for you, or else you will have to bear with a risk of being exploited. A search of your local yellow pages or an inquiry at your neighborhood computer store should yield professional help and get your private data private again.
Posted in Networks
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