With this in mind, here are some common Cisco cable types and their primary use.

First, there's the regular old "straight-through cable", so named because the eight wires inside the cable go straight through the wire. While the wires may be twisted inside to reduce electromagnetic interference (EMI), the wire that's connected to Pin 1 on one end is connected to Pin 1 on the other end, and so on. In a home lab, a straight-through cable is often used to connect a switch port to an Ethernet port on a router, with a transceiver attached to the Ethernet port. Straight-through cables are also good for connecting a BRI interface to an ISDN simulator.

The "crossover cable" is so named because the wires do cross over between pins. This allows the devices to both send and receive at the same time, and crossover cables are a must for directly connecting ports on Cisco switches to create a trunk.

The "rollover cable" allows you to connect directly to a Cisco console port with your laptop or PC. This is the blue cable that comes with new Cisco devices, and it's the one that engineers tend to hold on to with their lives. Without a rollover cable (also commonly called a "console cable"), you can't connect your laptop directly to a Cisco device.

Finally, there's the DTE/DCE cable. To create a frame relay cloud in your home lab (using one of your Cisco routers as a DCE), or to directly connect two Cisco routers via their serial interfaces, you will need a DTE/DCE cable. Remember that the DCE interface will need to supply clockrate to the DTE interface.

The different cable types can be confusing when you first read about them, but after tearing down or building your home lab a few times, you'll definitely have them straight come test day!

Best of luck in your lab and your exams,

Chris Bryant

CCIE #12933
About the Author

Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage (http://www.thebryantadvantage.com), home of free CCNA and CCNP tutorials! For my FREE "How To Pass The CCNA" or "CCNP" ebook, write to chris@thebryantadvantage.com !

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A Quick Note From The Publisher... If you like the article above, you may be interested in the following article which is also related to Cisco... Cisco Certification: How To Build Your Own Home Lab CCNA and CCNP candidates hear it all the time: “Get some hands-on experience”. From my personal experience climbing the Cisco certification ladder, I can tell you firsthand that there is no learning like hands-on learning. No simulator in the world is going to give you the experience you will get cabling and configuring your own routers. Whenever I mention this to one of my students, they always say it costs too much. The truth is, it is cheaper now to build your own CCNA and CCNP lab than it has ever been. The secret? Used routers. The word “used” turns off a lot of people not many of us buy used computers or used servers. Cisco routers, though, are robust. I personally own a Cisco 4000 router that I use as a Frame Relay switch in my lab that I’ve had for about four years, and I’ve never had a problem with it. The good news for current CCNA and CCNP candidates interested in building their own labs is that used Cisco equipment has never been more plentiful or cheaper. eBay is...