Certifications

What is the difference between a Repeater, Hub, and Switch?

One of the junior admins at my company was studying for his Cisco CCNA. He asked me about Repeaters, Hubs, and Switches. What is the difference? Well, let’s see. A repeater does exactly that- it repeats any electrical signals that come into one port, out its other port. (there are only 2 ports on a repeater). It is a very “dumb” device (no offense to any of you repeaters out there).

Hubs are very similar to repeaters. A Hub is essentially a multiport repeater. Any electrical signal that comes into one port, goes out all other ports. Again, a very dumb device.

A repeater and a hub both work on the Physical Layer of the OSI Model.

On the other hand, you have a switch. A switch is much more intelligent. It keeps track of all Ethernet devices connected to it using their MAC address and recording what port that MAC address is connected to. Then, it intelligently uses that table (MAC Address table) to switch Ethernet frames only to the Ethernet port where that traffic is destined to go to. This saves bandwidth and PC processing power. Additionally, most switches have mangement capabilities that allow you to see what is going on, see what device is on what port, if there are any errors, and configure speed & duplex.

A switch works at the Data-Link layer of the OSI Model, Layer 2.

All of these facts are excellent to remember for your Cisco CCENT/CCNA certification.

Learn how Train Signal’s FREE Training website can help you

Train Signal makes some excellent video training products (covering Windows 2008, Cisco, and much more) but I want to take a second to talk about their sister site - Train Signal Training.com (called TST).

At Train Signal Training, they have a lot of experts who make daily blog posts covering all sorts of Windows, Microsoft office, and Cisco networking topics.  For example, there are tips on how to get a networking job, tips on how to do a address label merge in Word 2007, and many more.  What is most impressive is how their writers deliver these real-world and very useful tips.

Please take a second to check out Train Signal Training and sign up for their free newsletter or RSS feed.

Introduction to the Petri IT Knowledgebase - www.petri.co.il

Have you used the Petri IT Knowledgebase? This website is an excellent source for all sorts of Windows, Cisco, Virtualization, CompTIA, and Wireless HOW-TO information. On this site, you will find over 1000 articles covering Windows Vista, Server 2008, Server 2003, Cisco networking, VMware Virtualization, and so much more. Additionally, there are forums filled with thousands of messages and many experts are available to answer technical questions. To check it out, use the link above and if you are looking for Cisco-specific articles, checkout the Petri Cisco index.

A complete CCNP video training package, now available!

Train Signal video training recently announced their ISCW video for th CCNP certification series. With this, they now offer a complete CCNP video training package!

You get a 12-20+ hour video for each of the CCNP certifcation exams. Specifically, you get…

What You Get:

	BSCI Training Videos - Master Cisco Routers 20+ Hrs of Instructor Led Video Training 150 Practice Exam Questions for the 642-901 BSCI Exam Topics Covered
	BCMSN Training Videos - Deploying and Managing Cisco Switches 12+ Hrs of Instructor Led Video Training 210 Practice Exam Questions for the 642-812 BCMSN Exam Topics Covered
	ONT Training Videos - Optimizing a Cisco Network For Rich Media 8+ Hrs of Instructor Led Video Training 120 Practice Exam Questions for the 642-845 ONT Exam Topics Covered
	ISCW Training Videos - Create and Manage a Secure Remote Cisco WAN 10+ Hrs of Instructor Led Video Training 400+ Page Instructor Lab Book of Instructor Notes Topics Covered

I have watched most of these videos and have been very impressed! They are created by my friend and fellow CCIE, Chris Bryant. You can watch a free demo of these video at: Train Signal CCNP Video package.

Good luck on your CCNP certification!

Would you “Rent” your certification?

I heard about a website that connects people who have certifications with Microsoft and Cisco resellers who need certified people, on the payroll, to achieve a certain level of reseller status.

How this works is - say that I sell Cisco equipment but I want larger discounts from Cisco (so I can make more profit when I sell it). To be a higher level of reseller (Silver, Gold, or whatever), you have to have a certain number of Cisco certified people on the payroll. For example, maybe you need 2 CCNA, 1 CCNP, and 1 CCIE.

Many up-and-coming resellers cannot afford to do this so the idea came that they could pay people who have these certs a flat monthy fee to register their cert # under the reseller’s name. Not a bad idea, I suppose, unless Cisco or Microsoft stop them.

And now an even better idea - www.rentacert.com

This site connects the people who have the cert with the resellers who want to “rent” it. The site makes a profit by taking a commission.

If you work for a company that is NOT a reseller but you have a cert, I suppose it would be nice to make some extra cash off of it and do nothing. It seems that both the renter and rentee would benefit but, I suppose the customer of that reseller looses out because the reseller really doesn’t have as much experience on hand as, perhaps, the other resellers at a similar level.

What do you think?

Would you rent your cert?

David Davis, CCIE

Personal Website: HappyRouter.com - home of Cisco how-to articles & videos
David Recommends:
HappyRouter Cisco CCNA & CCNP Video Training Series
Cirro - Quote Telecom Internet, Voice, and Data T1 circuits from an unbiased source