Tech Search

Preparing to pass the CCNA exam and earn this important Cisco certification? Route summarization is just one of the many skills you'll have to master in order to earn your CCNA. Whether it's RIP version 2, OSPF, or EIGRP, the CCNA exam will demand that you can flawlessly configure route summarization.

 

Route summarization isn't just important for the CCNA exam. It's a valuable skill to have in the real world as well. Correctly summarizing routes can lead to smaller routing tables that are still able to route packets accurately - what I like to call "concise and complete" routing tables.

The first skill you've got to have in order to work with route summarization is binary math; more specifically, you must be able to take multiple routes and come up with both a summary route and mask to advertise to downstream routers. Given the networks 100.16.0.0 /16, 100.17.0.0 /16, 100.18.0.0 /16, and 100.19.0.0 /16, could you quickly come up with both the summary address and mask? All you need to do is break the four network numbers down into binary strings. We know the last two octets will all convert to the binary string 00000000, so in this article we'll only illustrate how to convert the first and second octet from decimal to binary.
{mosgoogle}
100 16 = 01100100 00010000


100 17 = 01100100 00010001


100 18 = 01100100 00010010


100 19 = 01100100 00010011


To come up with the summary route, just work from left to right and draw a line where the four networks no longer have a bit in common. For these four networks, that point comes between the 14th and 15th bits. This leaves us with this string: 01100100 000100xx. All you need to do is convert that string back to decimal, which gives us 100 for the first octet and 16 for the second. (The two x values are bits on the right side of the line, which aren't used in calculating the summary route.) Since we know that zero is the value for the last two octets, the resulting summary network number is 100.16.0.0.

But we're not done! We now have to come up with the summary mask to advertise along with the summary route. To arrive at the summary route, write out a mask in binary with a "1" for every bit to the left of the line we drew previously, and a "0" for every bit to the right. That gives us the following string:

11111111 11111100 00000000 00000000

Converting that to dotted decimal, we arrive at the summary mask 255.252.0.0. The correct summary network and mask to advertise are 100.16.0.0 252.0.0.0.

For the CCNA exam, emphasis is put on knowing how to advertise these summary routes in RIPv2 and EIGRP. For both of these protocols, route summarization happens at the interface level - it's not configured under the protocol. On the interface that should advertise the summary route, use the command "ip summary-address". Here are examples of how the above summary route would be configured on ethernet0 in both RIPv2 and EIGRP.

R1(config-if)#ip summary-address rip 100.16.0.0 255.252.0.0

R1(config-if)#ip summary-address eigrp 100 100.16.0.0 255.252.0.0

The main difference between the two is that the EIGRP command must specify the AS number - that's what the "100" is in the middle of the EIGRP command. Since RIPv2 does not use AS numbers, there's no additional value needed in the configuration.

For OSPF, the commands differ. If you're configuring inter-area route summarization, use the "area range" command; if you are summarizing routes that are being redistributed into OSPF, use the summary-address command under the OSPF routing process on the ASBR. Neither of these are interface-level commands.

I speak from experience when I tell you that practice makes perfect on the CCNA exam, especially with binary and summarization questions. The great thing about these questions is that there are no grey areas with these questions - you either know how to do it or you don't. And with practice and an eye for detail, you can master these skills, pass the exam, and become a CCNA. Here's to your success!


Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage ( http://www.thebryantadvantage.com ), home of free CCNA and CCNP tutorials, The Ultimate CCNA Study Package, Ultimate CCNP Study Packages, and CCNA CBT video training. Pass the CCNA exam and CCNP exam with Chris Bryant, CCIE #12933!
For a copy of his FREE "How To Pass The CCNA" or "How To Pass The CCNP" ebook and receive a FREE CCNA and CCNP question every day, just visit the website and claim your free copies!

Preparing for your BSCI exam on your way to the Cisco CCNP certification, you can quickly get overwhelmed by the details! Here are five commonly overlooked points you should keep in mind when it comes to your OSPF studies.

 

The virtual link command includes the area number of the transit area, and if authentication is being used on Area 0, the virtual link command must include the authentication statement. Since the virtual link is a logical extension of Area 0, it stands to reason that it has to be configured with the authentication type and password configured on Area 0.

OSPF requires no seed metric when routes are being redistributed into an OSPF domain. The default cost for such routes is 20, but you do need to use the "subnets" option if you want to redistribute subnets into OSPF.
{mosgoogle}
There are two kinds of external OSPF routes. The default, E2, reflects the cost of the path from the ASBR to the external destination. The other option, E1, has a cost reflecting the entire path from the local router to the external destination.

When configuring stub areas, each router in the area must agree that the area is stub. For a total stub area, only the ABR needs to be configured with the "no-summary" option, but all routers in the area still must agree that the area is stub.

Routers in a stub area will have a default route to use to reach external destinations; routers in total stub areas will have a default route to use in order to reach both external and inter-area networks.

The BSCI exam and CCNP certification require a great deal of dedication and hard work. Keep studying and paying attention to the details, and you will get there!

Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage ( http://www.thebryantadvantage.com ), home of free CCNA and CCNP tutorials, The Ultimate CCNA Study Package, Ultimate CCNP Study Packages, and CCNA CBT video training. Pass the CCNA exam and CCNP exam with Chris Bryant, CCIE #12933!
For a copy of his FREE "How To Pass The CCNA" or "How To Pass The CCNP" ebook and receive a FREE CCNA and CCNP question every day, just visit the website and claim your free copies!

When you're studying for your CCNA exam on the way to earning this coveted Cisco certification, the details can seem overwhelming! In this article, I'll point out five Frame Relay details that you must keep in mind when you're on your way to the CCNA exam!

 

Inverse ARP starts working as soon as you open the serial interface. This protocol performs dynamic Frame Relay mapping, but you don't have to enable it - it's already enabled as soon as you enter the command "encapsulation frame-relay".

When you're configuring Frame Relay map statements manually, remember that you're mapping the local DLCI to the remote IP address.

When you run "show frame map", the word "dynamic" indicates mappings created by Inverse ARP, and "static" indicates it was manually created.
{mosgoogle}
To spot possible LMI type mismatches, run "show frame lmi". A large number of Status Timeouts indicates that there may be an LMI problem between your router and the frame relay switch.

This last one is for the many of you building CCNA home labs. A frame relay switch is a great addition to your lab! While you're busy putting the configuration together, don't forget the global command "frame-relay switching" - it's this command that allows a Cisco router to act as a frame relay switch!


Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage ( http://www.thebryantadvantage.com ), home of free CCNA and CCNP tutorials, The Ultimate CCNA Study Package, Ultimate CCNP Study Packages, and CCNA CBT video training. Pass the CCNA exam and CCNP exam with Chris Bryant, CCIE #12933! For a copy of his FREE "How To Pass The CCNA" or "How To Pass The CCNP" ebook and receive a FREE CCNA and CCNP question every day, just visit the website and claim your free copies!

The decision to attend a computer training school is one of the most important you'll ever make, and even more important is which one to attend. Asking the right questions can give you an idea of whether a given IT school is a good investment. An earlier article I wrote on this subject was so popular that I thought I'd offer some more advice on the questions to ask before you write that check or take out that loan.

 

If the school offers a placement service, ask to talk to the people working in that department and ask them how they go about placing graduates. Most schools offer a list of companies that they've placed students with. Get this list and start calling some of these companies. Ask to speak to their HR department, and ask them for their opinion of the school. Even if they don't say a lot, their tone of voice can speak volumes.

Ask to meet some of their teachers, and don't be afraid to ask them how long they've taught at that particular school. If the average teacher has been there a while, that's a good sign. If there seems to be quite a bit of turnover at the school, that's not as good a sign.
{mosgoogle}
Another key area is the availability of the computer labs during class and after the class is over. Speaking from experience, I can tell you that getting hands-on experience with the various software and hardware you'll be working with in the field is the #1 way to get ahead - just reading books won't do it. If you're taking a router class, does the school have real routers for you to work on? If you're taking a PC repair class, are there plenty of PCs for everyone in your class to work on, or do you have to share?

You want classes that offer hands-on experience during class, and you should be able to get into the computer labs after class. You may not be able to use the labs at night if the school offers night classes, but again I speak from experience - the time you spend in the computer labs after class is just as valuable as the time you spend in class. Make sure the labs will be available after class - and then get in there and work!


Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage ( http://www.thebryantadvantage.com ), home of free CCNA and CCNP tutorials, The Ultimate CCNA Study Package, Ultimate CCNP Study Packages, and CCNA CBT video training. Pass the CCNA exam and CCNP exam with Chris Bryant, CCIE #12933!
For a copy of his FREE "How To Pass The CCNA" or "How To Pass The CCNP" ebook and receive a FREE CCNA and CCNP question every day, just visit the website and claim your free copies!

When you're preparing to pass the BSCI exam on the way to the coveted Cisco CCNP certification, you can be quickly overwhelmed by the sheer amount of BGP and OSPF knowledge you must demonstrate a mastery of. One set of details that some BSCI and CCNP candidates underestimate are the differences between the OSPF router types. The OSPF router types seem straightforward enough, but what you must keep in mind is that a router can fill more than one of these roles!

 

An OSPF Internal router has one rule - it must have all its interfaces in a single area. It does not mean that area has to be Area 0.

An OSPF Backbone router is a router with at least a single area in the OSPF backbone area, Area 0. A router can be both an Internal and Backbone router if all its interfaces are in Area 0.

An Area Border Router has at least one interface in Area 0 and another interface in a non-backbone area. ABRs are also one of two router types that can perform OSPF route summarization. (To advertise a summary route from one OSPF area to another, use the area range command on the ABR.)
{mosgoogle}
Finally, an ASBR is an OSPF router that is performing route redistribution by injecting routes from another source into the OSPF domain. This is the other OSPF router type that can perform route summarization; to summarize routes being redistributed into OSPF, use the summary-address command on the ASBR.

There are several commands you can use to determine the router types in a given OSPF area. The command "show ip ospf" will display quite a bit of information regarding the local router, and this includes whether that router is acting as an ABR or ASBR. To see the routes to the ABRs and ASBRs from the local router, run "show ip ospf border-routers".

Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage ( http://www.thebryantadvantage.com ), home of free CCNA and CCNP tutorials, The Ultimate CCNA Study Package, Ultimate CCNP Study Packages, and CCNA CBT video training. Pass the CCNA exam and CCNP exam with Chris Bryant, CCIE #12933! For a copy of his FREE "How To Pass The CCNA" or "How To Pass The CCNP" ebook and receive a FREE CCNA and CCNP question every day, just visit the website and claim your free copies!

When you're preparing to pass the CCNA exam and earn this coveted Cisco certification, you've got to be totally prepared for the many kinds of binary and subnetting questions Cisco may throw at you. You also have to be familiar with the different manners in which a subnet mask can be expressed, and that's where your knowledge of prefix notation comes in. Prefix notation is an alternate way to express the value of a subnet mask, as opposed to the more familiar dotted decimal format. Not only will you see prefix notation in Cisco documentation, but you'll probably see it on your CCNA exam. Consider the following two values:

 

255.255.255.0

/24

Believe it or not, those two values are exactly the same. The first mask is written out in the more familiar dotted decimal format, and you know by looking at those first three octets that every bit is set to "1", since the maximum value of such an octet is 255.

The second value represents the exact same mask, only this value is expressed in prefix notation. This particular value would be pronounced "slash twenty-four", and the 24 represents the number of consecutive ones that are set in the subnet mask.
{mosgoogle}
Those of us who hate to type numbers are particularly appreciative of this, since it means you'll have to type a lot less numbers to represent a subnet mask. In addition, it's a lot easier to discuss masks in prefix notation than dotted decimal. ("I thought about using a two-fifty-five two-fifty-five two-fifty-five zero mask ,but then decided to use a two-fifty-five two-fifty-five two-fifty-five one-twenty-eight mask...")

Be sure you're comfortable with prefix notation before taking your CCNA exam. As with Cisco documentation, you'll most likely see masks expressed in both dotted decimal and prefix notation, and you've got to be ready to use the both as well!


Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage ( http://www.thebryantadvantage.com ), home of free CCNA and CCNP tutorials, The Ultimate CCNA Study Package, Ultimate CCNP Study Packages, and CCNA CBT video training. Pass the CCNA exam and CCNP exam with Chris Bryant, CCIE #12933!
For a copy of his FREE "How To Pass The CCNA" or "How To Pass The CCNP" ebook and receive a FREE CCNA and CCNP question every day, just visit the website and claim your free copies!

Passing the CCNA exam and earning this coveted Cisco certification is an important step in your career, but it's not the end of your responsibilities as a CCNA! When you work with computer networks, you've got to be continually learning and staying up on the latest technologies and changes in the field. Part of this responsibility is keeping your CCNA current by meeting Cisco's recertification requirements.

 

Cisco requires CCNAs to recertify once every three years. While most CCNAs will move on to the CCNP in that time, if you choose not to you must meet certain requirements in order to keep your CCNA valid. Cisco does this to ensure that CCNAs keep their networking knowledge current, which in turn helps the CCNA certification valuable. And that's exactly what you want, since you worked so hard to earn your certification in the first place!

As of March 2006, there are five different options for recertifying as a CCNA. You can take and pass any of the following exams to renew your CCNA - the CCNA exam itself, the ICND exam, any 642 series exam, any Cisco Qualiied Specialist exam (except the Sales Specialist exams - those don't count!), or any CCIE Written Qualification exam.
{mosgoogle}
With all these options, there's an option that's just right for you. Whether you just want to renew your CCNA or pursue a Specialist, CCNP, or CCIE certification, you can easily renew your CCNA along the way. Just don't forget that keeping up with Cisco's latest recertification requirements is your responsibility, and that's easy to do - just visit Cisco's "Learning And Events" section on their website. Cisco will tell you what you need to do to keep your certification, but it's up to you to keep up with certification program changes! Once your certification expires, it's gone, so get in the habit of visiting Cisco's website to make sure you're up to date on important recertification requirements.

One of the best decisions you can ever make is to attend a computer training school. As I've written in several other articles, you have to ask the right questions before writing a check or taking out a student loan, but when you find the right school you are indeed on your way to a successful career.

 

There's a big difference between attending a tech school and excelling at the classes, though. Whether you just "float through" the school or really work hard is totally up to you. From my personal experience at such a school, I'd like to offer you one simple tip that will quadruple your chances of success at the school and in the job market.

Get there early and stay late.

When I attended a tech school years ago, I admit I was surprised that most of my classmates had what I call the "junior high school" mentality - they would get there late and leave as soon as class is over. Guess what? You're no longer in junior high. You're attending this school to create a career for yourself. Get to class early, get some extra study and work in while you're waiting for class to start, and then stay after class!
{mosgoogle}
The most important part of your computer school studies is getting hands-on experience with the technologies that you're learning. If you're taking a Cisco class, you need to work with a router or switch as often as you can. If you're learning a software program, you need to work with that program in the school's labs as much as possible. Reading books alone will not teach you everything you need to know. The best time to get extra work in is after class. You may not be able to work in the computer labs at night if the school offers night classes, but odds are there are very few people in there during the afternoon. You need to be one of those people.

Doing only what is required of you is not the path to excellence. You need to go beyond the requirements of the school and invest the extra time and effort into your career. I speak from experience - there is no field in the world that rewards individual effort more than the IT field. Develop the habit of going "above and beyond" today, and this will pay huge dividends for you in the future.


Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage ( http://www.thebryantadvantage.com ), home of free CCNA and CCNP tutorials, The Ultimate CCNA Study Package, Ultimate CCNP Study Packages, and CCNA CBT video training. Pass the CCNA exam and CCNP exam with Chris Bryant, CCIE #12933!
For a copy of his FREE "How To Pass The CCNA" or "How To Pass The CCNP" ebook and receive a FREE CCNA and CCNP question every day, just visit the website and claim your free copies!

When you're preparing for CCNA and CCNP exam success, the best investment you can make is to put together your own home lab. There is no better way to learn Cisco technologies and prepare for the CCNA, BSCI, BCMSN, CIT, and other exams than by working with the many protocols and services you'll need to master in order to pass the exams.

 

One of the most popular articles I've written over the few years dealt with buying and configuring a Cisco router as a frame relay switch. That article is still available on many websites (including my own), but I want to remind you that just because you configure a router as a frame relay switch, that doesn't mean you can't use it as a home lab router, too!

The global command "frame-relay switching" allows a Cisco router such as a 2520 or 4000 to perform just that, frame relay switching, but this command doesn't disable IP routing. Depending on the router model you use, you will most likely have some extra serial connectors as well as an ethernet port that you can use with your other routers in your home lab.
{mosgoogle}
Let's say you have a 2520 router as your frame relay switch. This switch has four serial ports and an AUI port. You could connect to up to four routers to the 2520's serial ports in order to serve as the frame relay switch for those other routers, and still assign an IP address to the ethernet port and run a routing protocol on the 2520. If you're connecting to less than four other routers as the frame relay switch, you can assign IP addresses to the leftover serial ports as well.

A frame relay switch is a tremendous addition to a CCNA / CCNP home lab, and if you use it as both a frame switch and a router, you get double the bang for your home lab buck!


Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage ( http://www.thebryantadvantage.com ), home of free CCNA and CCNP tutorials, The Ultimate CCNA Study Package, Ultimate CCNP Study Packages, and CCNA CBT video training. Pass the CCNA exam and CCNP exam with Chris Bryant, CCIE #12933!
For a copy of his FREE "How To Pass The CCNA" or "How To Pass The CCNP" ebook and receive a FREE CCNA and CCNP question every day, just visit the website and claim your free copies!

As you earn your CCNA and CCNP certification, you're going to have to get comfortable with manually summarizing routes. This isn't just another reason to learn binary math (although it's a good one!), but summarizing routes is a true real-world skill that can help your network operate more efficiently. So the question isn't just how to summarize routes, it's why.