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When you’re studying for the CCNP certification, especially the BSCI exam, you must gain a solid understanding of BGP. BGP isn’t just one of the biggest topics on the BSCI exam, it’s one of the largest. BGP has a great many details that must be mastered for BSCI success, and those of you with one eye on the CCIE must learn the fundamentals of BGP now in order to build on those fundamentals at a later time.

Path attributes are a unique feature of BGP. With interior gateway protocols such as OSPF and EIGRP, administrative distance is used as a tiebreaker when two routes to the same destination had different next-hop IP addresses but the same prefix length. BGP uses path attributes to make this choice.

The first attribute considered by BGP is weight. Weight is a Cisco-proprietary BGP attribute, so if you’re working in a multivendor environment you should work with another attribute to influence path selection.

The weight attribute is significant only to the router on which it is changed. If you set a higher weight for a particular route in order to give it preference (a higher weight is preferred over a lower one), that weight is not advertised to other routers.

BGP uses categories such as “transitive”, “non-transitive”, “mandatory”, and “optional” to classify attributes. Since weight is a locally significant Cisco-proprietary attribute, it does not all into any of these categories.

The weight can be changed on a single route via a route-map, or it can be set for a different weight for all routes received from a given neighbor. To change the weight for all incoming routes, use the “weight” option with the neighbor command after forming the BGP peer relationships.

R2(config)#router bgp 100

R2(config-router)#neighbor 100.1.1.1 remote-as 10

R2(config-router)#neighbor 100.1.1.1 weight 200

Learning all of the BGP attributes, as well as when to use them, can seem an overwhelming task when you first start studying for your BSCI and CCNP exams. Break this task down into small parts, learn one attribute at a time, and soon you’ll have the BGP attributes mastered.

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Once you get your CCNA and CCNP, you can’t just rest on your accomplishment. You’ve got to continue to study and add to your skill set – and then prove to Cisco you’ve been doing just that by recertifying.

Cisco recertification sounds like a pain, but it’s actually one of the best things to ever happen to computer certification, and it helps your career as well. One trap many LAN and WAN personnel fall into is that they fail to keep up with changes in technology, and if they happen to be laid off or want to change jobs, they’re unable to because they didn’t keep their skill set up.

Cisco’s recertification policies ensure that if you want to keep your CCNA, CCNP, or one of the other valuable Cisco certifications, you’ve got to take a Cisco recertification exam.

As of November 2005, to recertify as a CCNA, you need to pass either the current CCNA exam, ICND exam, or any 642 professional level or Cisco Qualified Specialist exam. (This does not include Sales Specialist exams.) Passing a CCIE written qualification exam also recertifies you as a CCNA. CCNAs are valid for three years.

For the CCNP, you need to pass the 642-891 Composite exam, a CCIE written qualification exam, or BOTH the BSCI and BCMSN exams (642-801 and 642-811, respectively.) CCNP certifications are valid for three years.

As you can see, you’ve got quite a few options either way. The one classic mistake you must not make is waiting too long to begin preparing for the exams, and give yourself a little leeway just in case you don’t recertify the first time around. Once the deadline passes, your certification is gone, and in the case of the CCNP that means taking all the exams again.

As a professional, it’s your responsibility to keep up with changes in the Cisco certification world, and this includes changes in the recertification program. Make a point of visiting the “Learning And Events” section of Cisco’s website regularly to look for changes in the certification program. And while you’re there, you just might see another cert that catches your eye!

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From the CCNA to the CCIE, ISDN is one of the most important technolgies you’ll work with. It’s also very common in the field ISDN is frequently used as a backup connection in case an organization’s Frame Relay connections go down. Therefore, it’s important to know ISDN basics not only for your particular exam, but for job success.

ISDN is used between two Cisco routers that have BRI or PRI interfaces. Basically, with ISDN one of the routers places a phone call to the other router. It is vital to understand not only what causes one router to dial another, but what makes the link go down.

Why? Since ISDN is basically a phone call from one router to another, you’re getting billed for that phone call — by the minute. If one of your routers dials another, and never hangs up, the connection can theoretically last for days or weeks. The network manager then receives an astronomical phone bill, which leads to bad things for everyone involved!

Cisco routers use the concept of interesting traffic to decide when one router should call another. By default, there is no interesting traffic, so if you don’t define any, the routers will never call each other.

Interesting traffic is defined with the dialer-list command. This command offers many options, so you can tie interesting traffic down not only to what protocols can bring the link up, but what the source, destination, or even port number must be for the line to come up.

One common misconception occurs once that link is up. Interesting traffic is required to bring the link up, but by default, any traffic can then cross the ISDN link.

What makes the link come down? Again, the concept of interesting traffic is used. Cisco routers have an idle-timeout setting for their dialup interfaces. If interesting traffic does not cross the link for the amount of time specified by the idle-timeout, the link comes down.

To summarize: Interesting traffic brings the link up by default, any traffic can cross the link once it’s up a lack of interesting traffic is what brings the link down.

Just as important is knowing what keeps the link up once it is dialed. Why? Because ISDN acts as a phone call between two routers, and it’s billed that way to your client. The two routers that are connected by this phone call may be located in different area codes, so now we’re talking about a long distance phone call.

If your ISDN link does not have a reason to disconnect, the connection could theoretically last for days or weeks before someone realizes what’s going on. This is particularly true when the ISDN link is used as a backup for another connection type, as is commonly the case with Frame Relay. When the Frame Relay goes down, the backup ISDN link comes up when the Frame Relay link comes back not billed for all that time.

To understand why an ISDN link stays up when it’s not needed, we have to understand why it stays up period. Cisco’s ISDN interfaces use the idle-timeout to determine when an ISDN link should be torn down. By default, this value is two minutes, and it also uses the concept of interesting traffic.

Once interesting traffic brings the link up, by default all traffic can cross the link. However, only interesting traffic resets the idle-timeout. If no interesting traffic crosses the link for two minutes, the idle-timer hits zero and the link comes down.

If the protocol running over the ISDN link is RIP version 2 or EIGRP, the most efficient way to prevent the routing updates from keeping the line up is expressly prohibiting their multicast routing update address in the access-list that is defining interesting traffic. Do not prevent them from crossing the link entirely, or the protocol obviously won’t work correctly.

With OSPF, Cisco offers the ip ospf demand-circuit interface-level command. The OSPF adjacency will form over the ISDN link, but once formed, the Hello packets will be suppressed. However, the adjacency will not be lost. A check of the adjacency table with show ip ospf adjacency will show the adjacency remains at Full, even though Hellos are no longer being sent across the link. The ISDN link can drop without the adjacency being lost. When the link is needed, the adjacency is still in place and data can be sent without waiting for OSPF to go through the usual steps of forming an adjacency.

This OSPF command is vital for Cisco certification candidates at every level, but is particularly important for CCNA candidates. Learn this command now, get used to the fact that the adjacency stays up even though Hellos are suppressed, and add this valuable command to your Cisco toolkit.

One myth about ISDN is that Cisco Discovery Packets keep an ISDN link up. CDP is a Cisco-proprietary protocol that runs between directly connected Cisco devices. There is a school of thought that CDP packets have to be disabled on a BRI interface in order to prevent the link from staying up or dialing when it’s not really needed. I’ve worked with ISDN for years in the field and in the lab, and I’ve never seen CDP bring up an ISDN link. Try it yourself the next time you’re working on a practice rack!

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I’ve been active in the Cisco Certification track for four years, working my way from the CCNA to the coveted Cisco Certified Internetwork Expert title, and during that time I’ve conducted job interviews and casual conversations with hundreds of CCNAs and CCNA candidates.

The CCNA is an exciting beginning to your Cisco career, but just having the certification simply isn’t enough. A recruiter or interviewer isn’t going to be impressed just with the cert you’ve got to have some real-world knowledge to back it up.

I’ve been down that road myself, and sat on both sides of the CCNA job interview table. With that in mind, I’d like to offer to you some tips on becoming a truly valuable and employable CCNA.

Get some hands-on experience. I know the trap well. You can’t get experience until you get a CCNA, and you can’t get a CCNA without real experience. Well, actually, you can, but do you want to? Working on simulators is fine to a certain extent, but don’t make the classic mistake of depending on them. I’ve seen plenty of CCNAs who were put in front of a set of routers and really didn’t know what to do or how to put together a simple configuration, and had NO idea how to begin troubleshooting.

There are CCNA classes that offer you the chance to work with industry experts on real Cisco equipment. Beyond that, you can put together your own CCNA rack for less than $1000 by buying used routers. Some people think that’s a lot of money, but this is the foundation of your career. Treat it that way. The work you do now is the most important work you’ll ever do. Do it on real Cisco equipment. The skills I learned as a CCNA helped me all the way up to the CCIE.

Besides, after you get your CCNA (and after that, hopefully you’ll choose to pursue the CCNP), you can always get some of your money back by selling the equipment. The hands-on experience you gain this way is invaluable.

Know binary math. Do NOT go the easy route of memorizing a subnet mask chart for the CCNA exam. I know some people brag about being able to pass the CCNA exam without really understanding binary math. I’ve seen those people on the other side of the interview table, and they’re not laughing when I ask them to do a subnetting question. They’re not laughing when they can’t explain or create a VLSM scheme. That chart does nothing to help you understand what’s going on.

If you can add and know the difference between a one and a zero, you can do binary math. Don’t let the name intimidate you. Become a REAL CCNA — learn binary math !

Run “show” and “debug” commands. No commands help you truly understand how things work in a Cisco network than show and debug commands. As you progress through the Cisco certification ranks, you’ll be glad you started using these at the CCNA level.

Do you need to know these commands for the exam? Probably not. Do you need them to be successul in the real world? Absolutely.

The Cisco certification track has been great to me, and it can boost your career as well, whether you stop at the CCNA, CCNP, or go all the way to the CCIE. It’s the skills you develop today that will truly make you a networking engineer. Don’t take shortcuts or get the attitude of “just passing the exam”.

It’s what you achieve after the exam that counts, and it’s the work you put in before passing the exam that makes those achievements possible. Good Luck with your Cisco Certification.

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There’s quite an emphasis on security in today’s networks, and that’s reflected in Cisco’s certification tracks. Cisco offers a CCIE Security track and the Cisco Certified Security Professional (CCSP) intermediate-level certification, but there is no real equivalent to the CCNA on the security side. Instead, Cisco offers several different Security Associate certifications.

The good news is that you’ve got a lot of security specializations from which to choose; the bad news is that you’ve got a lot of choices! In choosing a specialization, take some time to choose a certification that will be of practical use to you in your current position or in your “dream job”.

One of the more popular Security Associate certifications is the Cisco VPN Specialist certification. This two-exam track consists of a Securing Cisco Network Devices (SND, 642-551) exam and a Cisco Secure Virtual Private Networks (CSVPN, 642-511) exam. To earn the Cisco VPN Specialist exam, you must hold a valid CCNA certification.

What should you expect on these exams? On the SND exam, expect to be grilled on basic security features on both switches and routers, as well as VPN 3000 concentrators, PIXes, and IDS/IPS Sensors. You’ll need to be ready to configure and troubleshoot basic AAA configurations, access-lists, syslog, AutoSecure, and much more. You should also be solid with IPSec.

IPSec will also be part of your CSVPN exam. As you’d expect, you’ll also be expected to be quite good with the VPN 3000 Concentrator series, including browser configuration, creating users and group, the Windows VPN Software Client, and more.

This is a demanding certification that is an excellent addition to your resume and your skill set. For the latest on this and other Cisco certifications, you should regularly visit the Learning & Events section of Cisco’s website. As a Cisco certification candidate, it’s your responsibility to stay current of any additions and changes to Cisco’s certification paths – and it’s good for your career!

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