Showing posts with label crossover. Show all posts
Showing posts with label crossover. Show all posts

Wednesday, December 24, 2008

Cisco CCNA / CCNP Home Lab Tutorial: The (Many) Cable Types And Their Purposes

One of the most common questions I get from CCNA and CCNP candidates who are setting up their own home labs is "What cables will I need?" The answer is "It depends." As you know from your exam studies, the physical layout of your lab is what determines the cables you'll need. Let's take a look at the most common home lab cable types and when you will need them.

Straight-through cables have quite a few uses in a CCNA / CCNP home lab. You'll need them to connect a switch port to an AUI port on a router (and you'll need a transceiver for that as well). If you have an ISDN simulator, straight-through cables can be used to connect a router's BRI port to the simulator.

Crossover cables are used to connect switches and allow them to trunk. If at all possible, get two switches in your home lab. This will allow you to gain valuable experience in manipulating root bridge election, working with STP, and creating EtherChannels.

DTE/DCE cables are used to connect two routers via their serial cables. If you are planning on using a frame relay switch in your lab, you'll need several of these. You can also get some great practice in by directly connecting two routers and bringing the connection up (and making sure it stays up!). This is valuable practice for your CCNA exam.

Octal cables are used to connect an access server to each of the other routers and switches in your lab.

Finally, there's that precious blue cable, the rollover cable. Rollover cables (sometimes called "rolled cables") allow you to connect a host device directly to a router or switch's console port. These cables have a way of disappearing around an IT shop, so make sure to take one home - and leave it there!

Tuesday, December 23, 2008

Cisco CCNA / CCNP Certification Exam: Cabling Your Home Lab

More CCNA and CCNP candidates than ever before are putting together their own home labs, and there's no better way to learn about Cisco technologies than working with the real thing. Getting the routers and switches is just part of putting together a great CCNA / CCNP home lab, though. You've got to get the right cables to connect the devices, and this is an important part of your education as well. After all, without the right cables, client networks are going to have a hard time working!

For your Cisco home lab, one important cable is the DTE/DCE cable. These cables have two major uses in a home lab. To practice directly connecting Cisco routers via Serial interfaces (an important CCNA skill), you'll need to connect them with a DTE/DCE cable. Second, if you plan on having a Cisco router act as a frame relay switch in your lab, you'll need multiple DTE/DCE cables to do so. (Visit my website's Home Lab Help section for a sample Frame Relay switch configuration.)

If you have multiple switches in your lab, that's great, because you'll be able to get a lot of spanning tree protocol (STP) work in as well as creating Etherchannels. To connect your switches, you'll need crossover cables.

You'll need some straight-through cables as well to connect your routers to the switches.

Finally, if you're lucky enough to have an access server as part of your lab, you'll need an octal cable to connect your AS to the other routers and switches in your lab. The octal cable has one large connector on one end and eight numbered RJ-45 connectors on the other end. The large connector should be attached to the async port on your AS, and the numbered RJ-45 connectors will be connected to the console ports on your other routers and switches.

Choosing and connecting the right cables for your Cisco CCNA / CCNP home lab is a great learning experience, and it's also an important part of your Cisco education. After all, all great networks and home labs all begin at Layer One of the OSI model!

Monday, December 22, 2008

CCNA / CCNP Home Lab Tutorial: Assembling Your Cisco Home Lab

A CCNA or CCNP candidate who wants to be totally prepared for their exams is going to put together a home lab to practice on. With used Cisco routers and switches more affordable and plentiful then ever before, there's really no excuse to not have one!

With the many different models available, there is some understandable confusion among future CCNAs and CCNPs about which routers to buy and which ones to avoid. You can take almost any set of Cisco routers and put together a home lab; part of the learning process is taking what equipment you have available and putting together your own lab! For those of you preparing to start your home lab or add to your existing one, this article will list the routers I use in my Cisco pods. You certainly don't have to have all this equipment, but this will give you some good ideas on how to get started.

The most versatile router you can get for your CCNA / CCNP home lab is a 2520. These routers come with four serial ports, one ethernet port, and one BRI interface for ISDN practice. This mix of interfaces means you can actually use it as a frame relay switch while using the ethernet and BRI ports for routing. (There is no problem with using a lab router as both your frame relay switch and a practice router; for a frame relay switch sample configuration, visit my website!)

My pods consist of five routers and two switches, and three of the five routers are 2520s, due to their versatility. A recent ebay search showed these routers selling for $99 - $125, an outstanding value for the practice you're going to get.

I also use 2501s in my home labs. These have fewer interfaces, but the combination of two serial interfaces and one ethernet interface allows you to get plenty of practice.

A combination that works very well is using three 2520s; one as my dedicated frame relay switch, one as R1, and another as R2. Add a 2501 as R3, and you can have a frame cloud connecting R1, R2, and R3, a direct serial connection between R1 and R3, an Ethernet segment that includes all three routers, and an ISDN connection between R1 and R2 if you have an ISDN simulator. That combination will allow you to get a tremendous amount of practice for the exams, and you can always sell it when you're done!

2501s are very affordable, with many in the $50 range on ebay. It's quite possible to get three 2520s and one 2501 for less than $500 total, and you can get most of that money back if you choose to sell it when you're done.

With four routers to work with, you're probably going to get tired of moving that console cable around. An access server (actually a Cisco router, not the white boxes we tend to think of when we hear "server") will help you out with that. An access server allows you to set up a connection with each of your other routers via an octal cable, which prevents you from moving that console cable around continually. For an example of an access server configuration, just visit my website and look in the "Free Training" section.

Access server prices vary quite a bit; don't panic if you do an ebay search and see them costing thousands of dollars. You do NOT need an expensive access server for your CCNA / CCNP home lab. 2511s are great routers to get for your access server.

One question I get often from CCNA / CCNP candidates is "What routers should I buy that I can still use when I'm ready to study for the CCNP?" The CCIE lab changes regularly and sometimes drastically when it comes to the equipment you'll need. During my CCIE lab studies, I found that renting time from online rack rental providers was actually the best way to go. Don't hesitate when putting your CCNA / CCNP home lab together, wondering what will be acceptable for the CCIE lab a year or so from now. None of us know what's going to be on that equipment list, so get the CCNA and CCNP first - by building your own Cisco home lab!