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Posts Tagged ‘certification’

Candidates preparing to pass the CCNP exams are putting together Cisco home labs like never before. With CCNA and CCNP home lab equipment more affordable than ever, candidates have realized the importance of working on real Cisco routers and switches on the way to earning their certifications.

One question I get often from CCNP candidates is goes something like this: “I’m planning on pursuing the CCIE after I get my CCNP. What kind of routers and switches should I buy now in order to use the same equipment in my CCIE home lab?”

This is going to sound strange coming from me, because I’m the #1 proponent of CCNA and CCNP candidates buying their own home labs. When it comes to the CCIE, though, I have to say that you’re probably better off using rack rentals instead of investing big money now to buy more expensive equipment with which to earn your CCNP.

There are plenty of 2500 and 2600 routers out there that you can buy to prepare fully for your CCNA and CCNP exams that may not have the capability needed for IE preparation. (For instance, while 2500 routers are fantastic for CCNA and NP study, they shouldn’t be used for IE study.) The issue with buying more expensive equipment is that Cisco rightfully updates the CCIE lab equipment list twice a year, and these moves can prove very costly for those who get caught in the middle of these changes. Read the rest of this entry »

A Cisco access server is generally the last item a CCNA or CCNP candidate has on their mind when they’re putting together a home lab. The thinking tends to be that since this router isn’t really doing anything in the production part of your practice lab, it’s not really important.

Once you have more than two devices in your home lab, though, you’ll realize that constantly moving the console cable around from one router to another gets very tiresome. That’s what an access server does for a home lab – it allows you to connect your PC to a single device when working in your home lab, with no need to constantly disconnect and reconnect the console cable. The console cable will be connected directly to the access server, and the access server is connected to all the other devices in your home lab. Once you start working with one, you’ll wonder how you got along without it!

The term “access server” is a little misleading. This is not a server in the traditional sense, it’s a Cisco router with asynchronous serial ports. It is these ports that you’ll use to connect to the other devices in your home lab. Two affordable models of access servers are Cisco 2509s and Cisco 2511s. They can be found on ebay as well as other vendors on the Net.

You will also need an octal cable. On one end, the cable has a large connector that will connect to the access server. The other end is actually eight separate cables, each with RJ-45 connectors. These connectors are numbered 1 – 8 and will be connected to the console port on each router and switch. It is important to note the number on each connector you’re connecting to the other lab devices.

Now that you’ve got the physical equipment, let’s take a look at a typical configuration of an access server:

no service password-encryption

no service udp-small-servers
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ISDN is a vital topic for today’s CCNA and CCNP candidates, especially for the ICND and Intro exams – you’ve got to know ISDN inside and out to pass those exams. Naturally you want to include it in your home lab. What many candidates don’t realize is that you can’t connect two Cisco routers directly via their Basic Rate Interface (BRI) interfaces you’ve got to have another device between them called an ISDN simulator.

An ISDN simulator is not one of those software programs pretending to be routers (“router simulators”) this is a piece of hardware that acts as the telephone company in your home lab. Older simulators come with preprogrammed phone numbers and SPIDs, where newer ones let you program the phone numbers you want to use. Either way, an ISDN simulator is great for your CCNA/CCNP home lab, because you can practice dial scenarios that actually work. And you get to troubleshoot the ones that don’t, which is also important to learn! )
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To earn your Cisco CCNA and CCNP certifications, you’ve got to master ISDN – and despite what some people say, there’s still a lot of ISDN out there that needs to be supported. And when it comes to troubleshooting ISDN, there’s a lot to look at. Is the correct ISDN switchtype configured? Are the dialer map statements correct? What about the dialer-group and dialer-list commands? And that’s just the start.

I always say that all troubleshooting starts at Layer 1, the Physical layer of the OSI model. The usual method of troubleshooting ISDN is sending pings across the link, but the connection can be tested without using pings or even before assigning IP addresses to the BRI interfaces!

It’s a good idea to place these test calls before configuring the interfaces – that way, you know you’ve got a valid connection before beginning the configuration (and there’s a lot of config to go along with ISDN!)

To place a test call without using pings, use the isdn call interface command.

R1#isdn call interface bri0 8358662

R1#

03:54:43: BR0 DDR: Attempting to dial 8358662

03:54:43: %LINK-3-UPDOWN: Interface BRI0:1, changed state to up

03:54:44: BR0:1 DDR: dialer protocol up

03:54:45: %LINEPROTO-5-UPDOWN: Line protocol on Interface BRI0:1, changed state to up

03:54:49: %ISDN-6-CONNECT: Interface BRI0:1 is now connected to 8358662 R2

To tear the test call down correctly, use isdn disconnect interface. IOS Help displays the options with this command.
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