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! )

You don’t need any special cables or connectors you just connect both of your routers’ BRI interfaces to the ISDN simulator with a straight-through cable and you’re ready to go.
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To pass the BSCI exam and move one step closer to CCNP certification success, you’ve got to know how and when to use debug commands to troubleshoot and verify network operations. While you should never practice debug commands on a production network, it’s important to get some hands-on experience with them and not rely on “router simulators” and books to learn about them.

When it comes to RIP, “debug ip rip” is the primary debug to use. This debug will show you the contents of the routing update packets, and is vital in diagnosing RIP version mismatches and routing update authentication issues.

You know how to use the variance command to configure unequal-cost load-sharing with IGRP, but IGRP has no topology table that will give you the feasible successor metrics you need. With IGRP, you need to use the “debug ip igrp transactions” command to get these vital metrics.
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One of the first things you learned about Frame is that the LMI also serves as a keepalive, or a heartbeat – and if three consecutive LMIs are missed, the line protocol goes down. There’s a limitation to LMI as a keepalive, though. The LMI is exchanged only between the DTE and the closest DCE. The LMI is therefore a local keepalive that does not reflect any possible issues on the remote end of the virtual circuit.

Taking the LMI concept to the next logical level, Frame Relay End-To-End Keepalives (FREEK, one of the least-heard Cisco acronyms for some reason) are used to verify that endpoint-to-endpoint communications are functioning properly.

What you have to keep in mind about FREEK is that each and every PVC needs two separate keepalive processes. Remember, with a PVC, there’s no guarantee that the path taking through the frame relay cloud to get from R1 to R2 is going to be the same path taken to go back from R2 to R1. One process will be used to send requests for information and handle the responses to these requests; this is the send side. When the send side transmits a keepalive request, a response is expected in a certain number of seconds. If one is not received, an error event is noted. If enough error events are recorded, the VC’s keepalive status is marked as down.

The process that responds to the other side’s requests is the receive side.

This being Cisco, we’ve got to have some modes, right? FREEK has four operational modes.

Bidirectional mode enables both the send and receive process enabled on the router, meaning that the router will send requests and process responses (send side) and will also respond to remote requests for information (receive side).

Request mode enables only the send process. The router will send requests and process responses to those requests, but will not answer requests from other routers.
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Whether you’re just starting to think about passing the CCNA or CCNP exams, or you’ve been on the certification track for a while, you’ve got to have a plan for success. If you wanted to drive your car from Florida to California, you’d create a plan to get there. You’d get a map and decide how far you wanted to drive per day, and maybe even make some hotel reservations in advance. You certainly wouldn’t get in your car, just drive it randomly down the nearest highway, and hope you ended up in California, would you?

Certainly not. Earning your CCNA certification is the same way. It’s not enough to just study a few minutes “when you feel like it”, or tell yourself that you’ll start studying for the exams “when I get such-and-such done”. The perfect time to start on the road to Cisco certification is not tomorrow, and it’s not next week. It’s today.

You’re much better off with one hour of solid study than three hours of interrupted, unfocused study. Here are a few ways to go about getting the kind of quality study time that will get you to the CCNA or CCNP (or any Cisco certification, for that matter!).

Schedule your study time, and regard this study time as you would an appointment with a client. If you were to meet a customer at 10:00 to discuss a network install, would you just decide not to show up and watch television instead? Not if you wanted the job. The same goes for your study time. That’s an appointment with the most important customer of all – YOU.

Turn your cell, iPod, TV, instant messenger, and all other electronic collars off for the duration of your study time. I know those of us in information technology don’t like to say this, but we can actually exist without being in touch with the world for a little while. You may even get to like it! Having uninterrupted study time is key to CCNA and CCNP exam success.

Finally, schedule your exam before you start studying. Contrary to what many people think, “deadline” is not a dirty word. We do our best work when we have a deadline and a schedule to keep. Make out your study schedule, schedule your exam, and get to work just as you would a network project for a customer. The project you’re working on is your career and your life, and by following these simple steps you can make it a highly successful project – by passing your CCNA and CCNP exam!

When you’re studying for the CCNA and CCNP exams, you’ve got a lot of different choices when it comes to training. One popular choice is choosing one of the many “boot camps” and five-day in-person courses that are out there. I’ve taught quite a few of these, and while many of them are good, they do have drawbacks.

Of course, one is cost. Many employers are putting the brakes on paying for CCNA and CCNP boot camps, and most candidates can’t afford to pay thousands of dollars for such a class. Then you’ve got travel costs, meals, and having to possibly burn your own vacation time to take the class. Add in time away from your family and boot camps become impractical for many CCNA / CCNP candidates.

Another issue is fatigue. I enjoy teaching week-long classes, but let’s face facts – whether you’re training for the CCNA or CCNP exams, you’re going to get a lot of information thrown at you in just a few days. You’re going to be mentally and physically exhausted at the end of the week, and that’s when some boot camps actually have you take the exam! You’ve got to be refreshed and rested when you take the exam to have your best chance of success.

How can you get the benefit of an experienced instructor without paying thousands of dollars? By taking a Video Boot Camp! There are some high-quality computer-based training (CBT) courses out there, and these courses offer quite a few advantages for the CCNA and CCNP candidate. These courses run hundreds instead of thousands of dollars, and you can train on your own schedule. It is important for you to make and keep that schedule, but instead of spending thousands of dollars and having to travel, you can get world-class CCNA and CCNP training in the comfort of your own home.

By combining a high-quality CCNA or CCNP CBT or video boot camp with a strong work ethic, you’re on your way to passing the exam and accelerating your career. Now get to work!

CCNA and CCNP candidates are well-versed in Spanning-Tree Protocol, and one of the great things about STP is that it works well with little or no additional configuration. There is one situation where STP works against us just a bit while it prevents switching loops, and that is the situation where two switches have multiple physical connections.

You would think that if you have two separate physical connections between two switches, twice as much data could be sent from one switch to the other than if there was only one connection. STP doesn’t allow this by default, however in an effort to prevent switching loops from forming, one of the paths will be blocked.

SW1 and SW2 are connected via two separate physical connections, on ports fast0/11 and fast 0/12. As we can see here on SW1, only port 0/11 is actually forwarding traffic. STP has put the other port into blocking mode (BLK).

SW1#show spanning vlan 10

(some output removed for clarity)

Interface Role Sts Cost Prio.Nbr Type

Fa0/11 Root FWD 19 128.11 P2p

Fa0/12 Altn BLK 19 128.12 P2p

While STP is helping us by preventing switching loops, STP is also hurting us by preventing us from using a perfectly valid path between SW1 and SW2. We could literally double the bandwidth available between the two switches if we could use that path that is currently being blocked.
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