Cisco CCNA Certification Error Detection vs. Error Recovery

Passing the CCNA, Intro, and ICND exam is all about knowing and noticing the details. (Which makes perfect sense, since becoming a master networking administrator or engineer is also about noticing the details!) One such detail knows the difference between error detection and error recovery. While the terms are sometimes used interchangeably, they are not the same thing.

Error detection is just that - error detection only. Two common error detection methods are found at the Data Link layer of the OSI model, the FCS (Frame Check Sequence) and CRC (Cyclical Redundancy Check). A mathematical equation is run against the data in the frame, and the result is sent along with the data. The receiver runs the equation again, but this time. If the result is the same, the frame is considered valid; if the result is different, the frame is considered corrupt and is discarded.

Note that the FCS and CRC do nothing in regards to retransmission. They are strictly error detection schemes.

For an example of error recovery, we look to the Transport layer, where TCP runs. TCP performs reliable delivery, and the reason we call it "reliable" is that TCP uses sequence numbers to detect missing segments. If the sender determines from the sequence numbers that the remote host did not receive transmitted segments, the sender will retransmit the missing segments.

The key to keeping the terms straight in your head is to remember that while both error detection and error recovery both detect problems, only error recovery does anything about it. It's also worth reading an exam question twice when you see either term!

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Palm Treo Getting Started With Your New Treo Smartphone

Copyright 2006 Christopher Meinck

Getting Started With a Palm Treo Smartphone

For many, adding a Palm Treo smartphone to their life is an exciting time. Most are coming from a traditional cellphone and the capabilities of a smartphone never seize to amaze. The Palm Treo features a large color LCD screen, full keyboard and software for syncing your personal data with your PC or Mac. Getting familiar with the capabilities of your new Treo smartphone can be overwhelming in the beginning. Once you get over the initial learning curve, owning a Treo can be a rewarding experience.

Protecting Your Treo

The Palm Treo is an expensive gadget, so you should make plans to protect your Treo. In the US, both Verizon and Sprint offer insurance on the Treo. For a fee of roughly $5, you can insure your Treo against loss or accidents. With insurance, youll have the piece of mind that your valuable Treo is protected. If your wireless provider does not offering insurance, another option is to sign up for the StuffBak protection program. Stuffbak is a loss prevention and recovery service. You purchase a Stuffbak label that gets applied to the back of your Treo. Should you lose your Treo, there is an 800# that allows the finder to collect a reward upon return.

Insurance and recovery services are both great options should something happen to your Treo. The best option is to protect your Treo smartphone with a good case and screen protector. There are many options when it comes to selecting a case for the Treo. When choosing a case, you can select from holster, pouch, skin, wallet and more. In most cases, its also a good idea to add a screen protector. Through the daily use of your Treo, you will find yourself touching the screen quite often. A screen protector will guard against scratches and its recommended even if youve opted for an enclosed case. Adding the correct Treo accessory can protect your smartphone for many years.

Treo Software

Out of the box, Palm OS based Treo smartphones comes bundled with all the software you need to sync with your PC or Mac. If you own a Mac, then you should avoid the Treo 700w. In order to sync the 700w with a Macintosh, you would have to use third party software such as Missing Sync by Mark/Space and they do not currently support the Treo 700w. If you are upgrading from a previous Palm device, youll still want to install the software that came with your new Treo. Follow the on-screen directions and youll be able to bring your data over to your new Treo. As a previous Palm owner, you should note that some applications might not work on your Treo. To be certain, locate and rename the Backup folder located in your User folder. Once youve completed the transfer of your PIM data, you can add one application at a time to insure compatibility with your Treo.

One of the great things about the Treo is vast catalog of available software applications. There are countless freeware and commercial applications. If you own a Palm OS based Treo, then be sure to look for software that supports your model. Owners of the Treo 700w should look for Pocket PC titles that support the Windows Mobile 5 operating system. In either case, its best to slowly add software. Adding incompatible software is the most common cause of an unstable Treo.

Get To Know Treo

The Treo is a remarkable device that offers robust software to help you manage your calendar, check email, browse the web, take photos, listen to MP3s and more. With any new technology, there is a slight learning curve and the Treo is no different. I encourage any new Treo owner to explore the features of their new smartphone. If you have questions, there are several good resources online or you can visit your local bookstore. Once youve mastered the basics, youll be left wondering how you ever managed without a Treo.

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Palm Treo Getting Started With Your New Treo Smartphone

Copyright 2006 Christopher Meinck

Getting Started With a Palm Treo Smartphone

For many, adding a Palm Treo smartphone to their life is an exciting time. Most are coming from a traditional cellphone and the capabilities of a smartphone never seize to amaze. The Palm Treo features a large color LCD screen, full keyboard and software for syncing your personal data with your PC or Mac. Getting familiar with the capabilities of your new Treo smartphone can be overwhelming in the beginning. Once you get over the initial learning curve, owning a Treo can be a rewarding experience.

Protecting Your Treo

The Palm Treo is an expensive gadget, so you should make plans to protect your Treo. In the US, both Verizon and Sprint offer insurance on the Treo. For a fee of roughly $5, you can insure your Treo against loss or accidents. With insurance, youll have the piece of mind that your valuable Treo is protected. If your wireless provider does not offering insurance, another option is to sign up for the StuffBak protection program. Stuffbak is a loss prevention and recovery service. You purchase a Stuffbak label that gets applied to the back of your Treo. Should you lose your Treo, there is an 800# that allows the finder to collect a reward upon return.

Insurance and recovery services are both great options should something happen to your Treo. The best option is to protect your Treo smartphone with a good case and screen protector. There are many options when it comes to selecting a case for the Treo. When choosing a case, you can select from holster, pouch, skin, wallet and more. In most cases, its also a good idea to add a screen protector. Through the daily use of your Treo, you will find yourself touching the screen quite often. A screen protector will guard against scratches and its recommended even if youve opted for an enclosed case. Adding the correct Treo accessory can protect your smartphone for many years.

Treo Software

Out of the box, Palm OS based Treo smartphones comes bundled with all the software you need to sync with your PC or Mac. If you own a Mac, then you should avoid the Treo 700w. In order to sync the 700w with a Macintosh, you would have to use third party software such as Missing Sync by Mark/Space and they do not currently support the Treo 700w. If you are upgrading from a previous Palm device, youll still want to install the software that came with your new Treo. Follow the on-screen directions and youll be able to bring your data over to your new Treo. As a previous Palm owner, you should note that some applications might not work on your Treo. To be certain, locate and rename the Backup folder located in your User folder. Once youve completed the transfer of your PIM data, you can add one application at a time to insure compatibility with your Treo.

One of the great things about the Treo is vast catalog of available software applications. There are countless freeware and commercial applications. If you own a Palm OS based Treo, then be sure to look for software that supports your model. Owners of the Treo 700w should look for Pocket PC titles that support the Windows Mobile 5 operating system. In either case, its best to slowly add software. Adding incompatible software is the most common cause of an unstable Treo.

Get To Know Treo

The Treo is a remarkable device that offers robust software to help you manage your calendar, check email, browse the web, take photos, listen to MP3s and more. With any new technology, there is a slight learning curve and the Treo is no different. I encourage any new Treo owner to explore the features of their new smartphone. If you have questions, there are several good resources online or you can visit your local bookstore. Once youve mastered the basics, youll be left wondering how you ever managed without a Treo.

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