Making the most of your CCNA study time is vital! Learn how to maximize your study efforts from Chris Bryant, CCIE #12933.

Keywords:
ccna, exam, study, plan, pass, free, tutorial, bryant, advantage, 12933, ccie, intro, icnd

To pass the CCNA exam, you’ve got to create a study plan. Part of that plan is scheduling your study time, and making that study time count.

You’ve scheduled your exam you’ve created a document to track your study time you’ve planned exactly when you’re going to study. Now the plan must be carried out, without exception.

What exceptions do I mean? Cell phones. Televisions. IPods. Significant others. The list can go on and on.

It’s one thing to have a plan, and an important thing now you’ve got to make sure you carry it out to its fullest potential. That’s easy to say until you’re studying and a friend calls, or you remember that TV show you wanted to watch is on tonight, or you start surfing the Web for Cisco information and end up playing a game.

You MUST make these small sacrifices in order to achieve your main goal, the CCNA. Any worthwhile accomplishment requires some small sacrifice.

TV will be there when you’re done studying. Your significant other will be there when you’re done studying. And believe it or not, people once existed without cell phones! Turn the phone off. Turn your instant messenger service off. Turn your text pager off. Despite what we think, the world can do without communicating with us for 90 minutes. Remember, it’s better to have 90 minutes of great study than 180 minutes of constantly interrupted study. Studies show that while a single phone call causes an 11-minute interruption on average, it takes well over 20 minutes to get back to what you were doing with the proper mental focus. This is true at the office and at your home!

How To Spend Your Study Time CCNA candidates generally spend their time split between book study, practice exams, and lab time on real Cisco equipment. The best study is done by a combination of these, not by overly relying on one. Let’s take a look at each method.

Book study – I’ve never understood why some people (usually the trolls we were talking about earlier) talk about book study like it’s a bad thing. “You can’t learn about technology from books.” What a load of manure. You have to learn the theory before you can understand how a router or switch operates. The best way to learn the theory is to read a good book.

At the CCNA level, you doubtless know that you have dozens of choices when it comes to books. Some of the better-known books really do gloss over some important topics, such as binary math and subnetting. Make sure to pick a book or books that go beyond just explaining the theory and that give you a lot of explanation of router configs and real-world examples as well.

Practice Exams: Practice exams are good in moderation, but don’t use them as your main focus of study. Occasionally, I’m asked for study tips by candidates who have taken the exam a few times and not passed yet. I ask them what they’re doing to prepare, and they give a list of companies they bought practice exams from. (You see a lot of this on Internet forums as well.)

Don’t fall into this trap. Practice exams are fine if used as a readiness check, but some candidates just take them over and over again, which renders them basically useless.

On top of that, some of them cost hundreds of dollars. That’s money you’d be much better off spending on Cisco equipment to practice on.

Again, I’m not against practice exams as a supplement to your studies. Just don’t make them the main focus of your study. Taking practice exams over and over and hoping the exam will be just like the practice exam is a recipe for disaster. As I tell my students, when you’re in front of a rack of routers and switches during a job interview (or at 2AM when you’ve been called in to fix a problem), the correct answer is not “D”. You’ve got to know what to do.

And how do you learn these skills? Funny you should ask…. Lab Time On Real Cisco Equipment. Again, speaking from experience: This is the most important part of getting your CCNA, succeeding on the job, and going on to get your CCNP.

Getting hands-on experience is critical to developing your networking skills, especially your troubleshooting skills. Although simulators are better than they used to be, they’re still not Cisco routers, and they never will be.

You do your best learning not only when you’re configuring your routers, but when you screw something up.

That’s so important, I want to repeat it – loudly: You do your best learning when you screw something up. Why? Because then you have to fix it that’s how you develop your troubleshooting skills. You can read about all the debug and show commands in the world, but you don’t really understand how they work until you’re figuring out why your Frame Relay connection isn’t working, or your RIP configuration isn’t working.

This is true at every level of the Cisco Learning Pyramid. I can show you the show ip protocols output or what you get when you run debug ip rip, and you might remember it for a little while. But when you use it to troubleshoot a lab configuration, you WILL remember it.

Putting your own practice lab together will also help get you over what I call “simulator question anxiety”. If you spend any time on CCNA Internet forums, you’ll see discussion after discussion about these exam questions. To a certain point, this discussion is justified. The simulator questions carry more weight on your exam than any other question while you can earn partial credit on them, you’ve got to get them right or you will most likely fail the exam.

There’s no reason to be anxious about them if you’re prepared. You don’t want to be the person who walks into the testing room that’s scared to have to create a VLAN or an access list you want to be the person who walks into the testing room confident of their ability to perform any CCNA task. The best way to be that confident is to know you’ve done it – on real Cisco equipment.

There are several vendors that sell routers and switches on ebay most of them sell CCNA and CCNP kits that include all the cables and transceivers that you’ll need as well. (And how is a simulator going to help you learn about cables and transceivers?) Keep in mind that you can always sell the equipment after you’re done with the CCNA, or you can add a little equipment to it to go after your CCNP.

Whichever of these methods you use (and I hope you’ll use all of them), make sure to keep them in balance with each other. Don’t depend too much on just one.

On the topic of learning how to troubleshoot… as you run labs on your Cisco equipment, you’ll run into questions or problems that you don’t know the answer to yet. Get used to using Google (or your favorite search engine) to find the answer to these problems – but try to figure it our yourself first!

There’s nothing wrong with asking questions of someone else if you’re not able to find the answer yourself. Trying to find the answer yourself is another important troubleshooting skill you need to start developing today. Don’t be one of these people who posts a simple question on a forum without trying to find the answer on your own. Besides, you get more satisfaction and build more confidence when you determine the answer yourself.

Share This

Learn how to put your CCNA / CCNP home lab together without spending too much money in this tutorial from Chris Bryant, CCIE #12933.

Keywords:
cisco, home, lab, ccna, ccnp, router, which, one, 2501, 2503, ccie, 12933, pass, exam, console, test

To be truly prepared for your CCNA and CCNP exams, you need real hands-on experience with real Cisco routers and switches. However, a production network is a really bad place to practice your configurations, but an excellent way to get fired and/or sued. The key to becoming a true CCNA and CCNP is assembling your own Cisco home lab.

You don’t have to spend a lot of money to do so; used Cisco equipment is cheaper than ever. It’s robust as well – I’ve bought literally hundreds of used routers and switches over the years and have had very few problems. I owe much of my skill to practicing configurations and troubleshooting in my own home lab.

2501 routers are fantastic for CCNA and CCNP home labs. They come with two serial interfaces, allowing you to connect one interface directly to another router (you’ll need a DTE/DCE cable for that, too) while connecting another to a frame relay switch if you like. If you don’t have a frame relay switch, you can connect a 2501 directly to two other routers via the serial interfaces.

You also have an AUI port, which requires a transceiver to operate as your Ethernet interface. Transceivers are pretty cheap and readily available from Cisco resellers and ebay vendors, so pick one up for each 2503 you decide to buy.

2501 routers don’t come with BRI interfaces, but not every router in your lab has to be ISDN-ready. If you choose not to have ISDN in your lab at all, 2501s are the way to go. If you do want to run ISDN and have an ISDN simulator device, you can get two 2503s and the rest of your routers can be 2501.

All in all, 2501 routers are great for your CCNA / CCNP home lab. They cost less than $100 each on ebay, so they’re also very affordable. There’s no better training than training on your own CCNA or CCNP home lab, and you can always sell the equipment later if you like. Basically, you’re renting the routers and switches, and the experience you get by working with the real deal is invaluable.

Share This

Frame Relay encapsulation seems simple enough, but for your CCNA and CCNP exams, you’ve got to know vital details that are often overlooked. Learn these details from Chris Bryant, CCIE #12933.

Keywords:
ccna, ccnp, cisco, certification, frame, relay, ietf, pvc, router, serial, interface, exam, pass

When you’re studying to pass the Cisco CCNA and CCNP certification exams, you quickly learn that there’s always something else to learn. (You’ll really pick up on this in your CCIE studies, trust me!) Today we’ll take a look at an often-overlooked topic in Frame Relay, the encapsulation type. You don’t exactly change this on a daily basis in production networks (not if you want to stay employed, anyway!), but it’s an important exam topic that you must be familiar with.

The DCE and DTE must agree on the LMI type, but there’s another value that must be agreed upon by the two DTEs serving as the endpoints of the VC. The Frame encapsulation can be left at the default of Cisco (which is Cisco-proprietary), or it can be changed to the industry-standard IETF, as shown below. If a non-Cisco router is the remote endpoint, IETF encapsulation must be used. Note that the default of Cisco isn’t listed as an option by IOS Help, so you better know that one by heart!

R1(config)#int s0

R1(config-if)#encap frame ?

ietf Use RFC1490/RFC2427 encapsulation

R1(config-if)#encap frame ietf

What if a physical interface is in use and some remote hosts require Cisco encapsulation and others require IETF? The encapsulation type can be configured on a per-PVC basis as well. One encap type can be used on the interface, and any map statements that require a different encap type can have that specified in the appropriate map statement. In the following example, all PVCs will use the default Cisco encapsulation type except for PVC 115. The frame map statement using that PVC has ietf specified.

R1(config)#int s0/0

R1(config-if)#encap frame

R1(config-if)#frame map ip 172.12.123.3 123 broadcast

R1(config-if)#frame map ip 172.12.123.2 122 ietf broadcast

show frame map shows us that the mapping to DLCI 123 is using Cisco encapsulation, and DLCI 122 is using IETF.

R1#show frame map

Serial0 (up): ip 172.12.123.3 dlci 123(0×7B,0×1CB0), static

broadcast, CISCO, status defined, active

Serial0 (up): ip 172.12.123.2 dlci 122(0×7B,0×1CB0), static

broadcast, ietf, status defined, active

Just remember that Cisco is the default, and all PVCs will use Cisco unless you specify IETF in the frame map statement itself. You could also change the entire interface to use IETF for all mappings with the frame-relay encapsulation IETF command. For Cisco exams, as well as work on production networks, it’s always a good idea to know more than one way to do something!

Share This

You’ve got to know the basics of routing protocols to pass the CCNA exam and the BSCI CCNP exam! Learn these important basics from Chris Bryant, CCIE #12933.

Keywords:
ccna, exam, protocol, ccnp, bsci, protocol, rip, igrp, eigrp, multicast, address, free, equal, cost

To earn your Cisco CCNA certification and pass the BSCI CCNP exam, you have to know your protocol basics like the back of your hand! To help you review these important concepts, here’s a quick look at the basics of RIPv1, RIPv2, IGRP, and EIGRP.

RIPv1: Broadcasts updates every 30 seconds to the address 255.255.255.255. RIPv1 is a classful protocol, and it does not recognize VLSM, nor does it carry subnet masking information in its routing updates. Update contains entire RIP routing table. Uses Bellman-Ford algorithm. Allows equal-cost load-balancing by default. Max hop count is 15. Does not support clear-text or MD5 authentication of routing updates. Updates carry 25 routes maximum.

RIPv2: Multicasts updates every 30 seconds to the address 224.0.0.9. RIPv2 is a classless protocol, allowing the use of subnet masks. Update contains entire RIP routing table. Uses Bellman-Ford algorithm. Allows equal-cost load-balancing by default. Max hop count is 15. Supports clear-text and MD5 authentication of routing updates. Updates carry 25 routes maximum.

IGRP: Broadcasts updates every 90 seconds to the address 255.255.255.255. IGRP is a Cisco-proprietary protocol, and is also a classful protocol and does not recognize subnet masking. Update contains entire routing table. Uses Bellman-Ford algorithm. Equal-cost load-balancing on by default; unequal-cost load-sharing can be used with the variance command. Max hop count is 100.

EIGRP: Multicasts full routing table only when an adjacency is first formed. Multicasts updates only when there is a change in the network topology, and then only advertises the change. Multicasts to 224.0.0.10 and allows the use of subnet masks. Uses DUAL routing algorithm. Unequal-cost load-sharing available with the variance command.

By mastering the basics of these protocols, you’re laying the foundation for success in the exam room and when working on production networks. Pay attention to the details and the payoff is “CCNA” and “CCNP” behind your name!

Share This

An access server is a great addition to your Cisco home lab, but configuring one can be a little confusing. Learn how to configure and troubleshoot your access server with Chris Bryant, CCIE #12933.

Keywords:
Ccna, ccnp, home, lab, access, server, free, pass, exam, octal, cable, bsci, bcmsn, Bryant, advantage, 12933, chris, router, switch, 2509, 2511

As your CCNA / CCNP home lab expands, an access server such as the Cisco 2509 or 2511 is one of the best investments you can make. In this article, we’ll look at the basic configuration for an access server and discuss how to connect to the other routers and switches in your pod through the AS.

Here’s part of a configuration from one of my access servers:

ip host FRS 2006 100.1.1.1

ip host SW2 2005 100.1.1.1

ip host SW1 2004 100.1.1.1

ip host R2 2002 100.1.1.1

ip host R1 2001 100.1.1.1

ip host R3 2003 100.1.1.1

interface Loopback0

ip address 100.1.1.1 255.255.255.255

no ip directed-broadcast

This is an IP Host table, and this is what makes the entire AS setup work. Your PC will connect to the access server, and the access server is in turn physically connected to your other routers and switches via an octal cable. One end of the octal cable splices off into eight separate cables, each terminated with an Rj-45 connector. That connector will be placed into the console port of one of your home lab devices. In this configuration, I have connector 1 connected to the console port of R1, connector 2 to R2, connector 3 to R3, connector 4 to Sw1, and so forth. (The connectors are physically numbered as well.)

The IP Host table entries here are linked to the loopback address shown. The loopback can be any address, but it must match the address in the IP Host table. This allows you to create reverse telnet sessions to the routers and switches.

To open the reverse telnet sessions upon opening a connection to the AS, type the entire name of the device and press the enter key twice. A connection to that device will now be visible, as shown here:

Access_Server#r1

Trying R1 (100.1.1.1, 2001)… Open

R1#

To get back to the access server, use the key combination followed by pressing the “x” key. Keep doing this until you’ve opened a connection to every router and switch in your pod.

Once you’ve opened the lines, you will not use the full device name to connect to the home lab devices. You should press only the number corresponding to the reverse telnet session you opened. For instance, in this configuration I opened telnet session 1 to R1, session 2 to R2, and session 3 to R3. Once I opened those sessions, I just use those numbers to reconnect to the devices, as shown here:

Access_server#1

[Resuming connection 1 to r1 ... ]

R1#

Access_server#2

[Resuming connection 2 to r2 ... ]

R2#

Access_server#3

[Resuming connection 3 to r3 ... ]

R3#

If you type the full hostname again after initially opening the connection, you will see this message:

Access_server#r1

Trying R1 (100.1.1.1, 2001)…

% Connection refused by remote host

The connection is refused because you already have an open connection to that router.

There’s one more important part of an access server config your CCNA / CCNP home lab will need:

line 1 8

no exec

transport input all

The line numbers may differ according to your access server, but “no exec” is very important here. This will stop rogue EXEC sessions from refusing connections that it shouldn’t be refusing. Without this command, you’ll commonly see “connection refused by remote host” when you shouldn’t be. That message is the most common error you’ll see on an access server, and it’s there because you already have an open connection or you left “no exec” out of your configuration. “No exec” isn’t mandatory, but it will help you keep your sanity!

Share This

OSPF hub-and-spoke networks have many details that you must know for the CCNA exam and the real world. Learn these vital details from Chris Bryant, CCIE #12933.

Keywords:
Ccna, cisco, certification, exam, free, tutorial, ospf, hub, spoke, neighbor, isdn, demand, circuit, adjacency

CCNA exam success depends greatly on knowing the details, and if there’s one protocol that has a lot of details, it’s OSPF! This is true particularly of hub-and-spoke networks, so in this CCNA OSPF tutorial we’ll take a look at some of the more important hub-and-spoke OSPF details. This will help you in working with real-world networks as well, since this OSPF network type is one of the more typical network topologies.

In OSPF, the hub must become the designated router (DR). The DR election’s deciding value is the OSPF interface priority, and the default value is 1. It’s not enough to set the hub’s OSPF interface to 2, however, since the spoke routers must not become the DR or BDR. You must set the spoke interfaces to an OSPF priority of zero.

R2(config)#int s0

R2(config-if)#ip ospf priority 0

This ensures that the spokes will not become the DR or BDR if the hub goes down.

The hub does require a bit more configuration, though. The neighbor command must be used on the hub to indicate the IP address of the potential neighbors.

R1(config)#router ospf 1

R1(config-router)#neighbor 172.12.123.2

R1(config-router)#neighbor 172.12.123.3

It’s common to have an ISDN link as a backup in an OSPF network, and when that ISDN link comes up the hello packets must be able to cross the link. What you don’t want is to have the hellos keep the link up! By configuring the ISDN link as an OSPF demand circuit, the link will drop in the absence of interesting traffic, but the OSPF adjacency that formed across the ISDN link will be assumed by the router to still be up. (You usually see this command configured on both sides of the ISDN link, but it’s only needed on one side. It doesn’t hurt anything to put it on both sides, though.)

R2(config)#int bri0

R2(config-if)#ip ospf demand-circuit

A final detail of OSPF hub-and-spoke and demand circuits actually takes place at Layer 2. For the OSPF hello packets to successfully be transmitted across an ISDN link or a frame relay network, the broadcast option must be enabled in the appropriate frame and dialer map statements. Failure to enable this option can lead to a situation where pings will be successful, but OSPF adjacencies will not form.

R2(config-if)#dialer map ip 172.12.21.1 name R1 broadcast 5551111

R2(config-if)#frame map ip 172.12.123.1 221 broadcast

When you’re troubleshooting OSPF in a production network or your CCNA / CCNP home lab, don’t just look at Layer 3 – because everything’s got to be right at the physical and data link layers in order for the network layer to function correctly!

Share This

You might know static routing, but what is a “floating static route”? Learn the details of this CCNP exam topic from Chris Bryant, CCIE #12933.

Keywords:
Ccnp, certification, exam, bsci, pass, floating, static, route, Bryant, advantage, ip, route, tutorial, ospf, administrative, distance, ad

Passing the BSCI exam and earning your CCNP certification demands that you add greatly to the networking skills foundation you created when you studied for your CCNA certification. You learned quite a bit about static routing and default static routing when you passed the CCNA test, and it does seem like that should be all you need to know about static routing, right?

One thing you’ll learn as you continue to earn Cisco certifications is that there’s always something else to learn! You may have heard the term “floating static route”, which does suggest some interesting mental pictures. “Floating”? Floating on what?

In a way, a floating static route is “floating” in your routing table. A floating static route is a route that will be used only if routes for the same destination but with a lower administrative distance are removed from the table. For example, you could be using an OSPF-discovered route as your primary route to a given destination, and the floating static route would serve as a backup route that would be used only if the OSPF route leaves the routing table.

Now, how can that happen? After all, OSPF has an administrative distance of 110 and static routes have ADs of one or zero, depending on whether it’s configured with a next-hop IP address or a local exit interface. One way or the other, 1 and 0 are still less than 110!

When you want to configure a floating static route, you must assign the route an AD higher than that of the primary route. In this case, we’ve got to create a static route with an AD higher than 110. We do this by using the “distance” option at the end of the “ip route” command.

R1(config)#ip route 110.1.1.0 255.255.255.0 172.12.123.1 ?

Distance metric for this route

name Specify name of the next hop

permanent permanent route

tag Set tag for this route

R1(config)#ip route 110.1.1.0 255.255.255.0 172.12.123.1 111

The number entered at the very end of the “ip route” command is the AD of that route. If there is an OSPF route for 110.1.1.0 /24, that will be the primary route, and the floating static route will not be used unless the OSPF route is taken out of the routing table.

Floating static routes aren’t just a good thing to know for the BSCI exam and your CCNP certification pursuit – they’re very practical in the real world as well.

Share This

DTP works transparently, but you need to know the details of this protocol to pass the BCMSN exam! Learn the vital details from Chris Bryant, CCIE #12933.

Keywords:
Dtp, trunk, ccnp, bcmsn, exam, free, tutorial, dynamic, trunking, protocol, switch, port, nonegotiate

When you’re studying to pass the BCMSN exam on the way to earning your CCNP certification, you’re going to add to your CCNA knowledgebase every step of the way. Nowhere is that more than configuring a trunk between two switches.

You know that IEEE 802.1Q (”dot1q”) and ISL are your two choices of trunking protocols, and you know the main differences between the two. What you might not have known is that there’s a third trunking protocol that’s running between your Cisco switches, and while it’s a transparent process to many, you had better know about it for your BCMSN and other CCNP exams!

The Cisco-proprietary Dynamic Trunking Protocol (DTP) actively attempts to negotiate a trunk link with the remote switch. This sounds great, but there is a cost in overhead – DTP frames are transmitted every 30 seconds. If you decide to configure a port as a non-negotiable trunk port, there’s no need for the port to send DTP frames.

DTP can be turned off at the interface level with the switchport nonegotiate command, but as you see below, you cannot turn DTP off until the port is no longer in dynamic desirable trunking mode. (Dynamic desirable is the default mode for most Cisco switch ports.)

SW2(config)#int fast 0/8

SW2(config-if)#switchport nonegotiate

Command rejected: Conflict between ‘nonegotiate’ and ‘dynamic’ status.

SW2(config-if)#switchport mode ?

access Set trunking mode to ACCESS unconditionally

dynamic Set trunking mode to dynamically negotiate access or trunk mode

trunk Set trunking mode to TRUNK unconditionally

SW2(config-if)#switchport mode trunk

SW2(config-if)#switchport nonegotiate

When you’re working with Cisco switches in a home lab or rack rental environment, run IOS Help regularly to see what options are available for the commands you’re practicing with. Cisco switch ports have quite a few options, and the best way to find them is with one simple symbol – the question mark!

Share This

Mastering all the BGP attributes can seem overwhelming, but by learning one at a time, you can master them quickly. Learn all about the BGP weight attribute in this CCNP tutorial from Chris Bryant, CCIE #12933.

Keywords:
Ccnp, bsci, certification, cisco, ccna, bgp, weight, attribute, path, selection, order, chris, Bryant, ccie, 12933, advantage, router, switch, igp

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.

Share This

Part of the fun and the confusion with CCNA / CCNP home labs is figuring out how to connect the equipment you have. Chris Bryant, CCIE #12933, walks you through this case study that shows you one possible configuration for one customer’s home lab.

Keywords:
ccna,ccnp,home,lab,router,switch,pass,free,exam,tutorial,intro,icnd,access,server,frame,relay,switch,dte/dce,crossover,network,topology,setup,loopback,interface,ethernet,serial,bri,isdn,simulator

Part of your CCNA / CCNP education is deciding what network topology to use when you’re putting together your home lab. Some of you are starting with one or two routers or switches, while others are starting with more. A customer recently sent me a list of his Cisco routers and switches that he has available for a home lab and asked for my help in coming up with the best way to use them.

There is no “right” or “wrong” answer to this question; again, part of the learning process is configuring and reconfiguring the physical topology of your lab. Let’s look at the routers and switches he has available, including the interfaces on each, and come up with one possible CCNA / CCNP home lab setup.

The equipment list:

Two 3620 routers. Each has 1 serial port and 2 ethernet ports.

One 3640 router. This has two ethernet cards, each with two ports, and two AUI ports.

Three 2503s, my personal favorite for home labs! These have 1 AUI port, 2 serial interfaces, and one BRI interface apiece.

One 2524 router. This has one serial port, 1 ethernet port, and one BRI interface.

One 4500 router. This has eight BRI ports, 2 ethernet ports, and more importantly, four serial ports.

He also has a 5200 access server, an ISDN simulator, one 2924 switch, and one 1924 switch.

Now, if you don’t have this much equipment to work with, don’t panic! Most CCNA / CCNP candidates don’t; this is more of an exercise in looking at what you do have and using it to the utmost.

As I’ve mentioned in many of my CCNA / CCNP home lab articles, an access server is a great thing to have. All he needs is an octal cable to connect his AS to the other devices we choose to use, and he’s all set. (If you need an access server sample configuration, there is one on my website in the Home Lab section.)

A frame relay switch is also great to have, and the 4500 will make a great FR switch. Having a frame relay cloud in your CCNA / CCNP home lab is a great way to get experience configuring and troubleshooting frame relay, an essential skill for CCNA success.

I would put both of the 3620s on the frame relay cloud via the Serial interface, as well as two of the 2503s. That gives you four routers that will be using frame relay to communicate, and that’s the most we can have since the 4500 has four serial ports. The 4500 will need to be configured as a frame relay switch and connected to the other routers via a DTE/DCE cable. (Again, if you need a frame relay switch configuration, the one I use in my pods is on the website in the same place as the access server configuration.)

The two 2503s that are on the frame relay cloud should also be connected via their BRI interfaces. The home lab also includes an ISDN simulator, which is necessary to allow routers to communicate via their BRI interfaces. Just get a couple of straight-through cables to connect those two routers to the ISDN simulator and that segment is ready to go. (Remember that you can’t connect Cisco routers directly via their BRI interfaces.)

All of the routers in this lab have at least one ethernet or AUI port, so we can connect them all to either one of the switches. The switches should be connected via at least two crossover cables to allow practice with trunking, root bridge election, and VLANs. Having two switches really does add quite a bit to a CCNA / CCNP home lab’s capabilities. You can experiment with different subnets and vlans with as well. Don’t be afraid to dive in – that’s what a home lab is all about!

So now we’ve got four routers connected via frame relay, two via ISDN, and the others via ethernet segments. Two of the routers that are not using their serial interfaces should be connected directly via their serial ports. For this, you’ll just need another DTE/DCE cable. Knowing how to bring up the line between two directly connected serial ports is an important CCNA skill, and so is troubleshooting it. You should be able to bring such a connection up with your eyes closed, and once you work with your own CCNA / CCNP home lab, you’ll be able to!

Also, don’t forget to add a loopback interface to each one of your routers. I like to use 1.1.1.1 for R1, 2.2.2.2 for R2, and so on. Advertising loopbacks is another great way to get practice with RIP, OSPF, EIGRP, IGRP, and static routing.

We’ve taken a pile of routers and switches and turned them into a fantastic CCNA / CCNP home lab. Whether you’re working with two Cisco devices or ten, coming up with your own home lab topology is a great learning experience and the beginning of developing your analytical and troubleshooting skills.

Share This

To pass your CCNA and CCNP exams, you must know when and how to use debug commands. Learn five vital debugs from Chris Bryant, CCIE #12933.

Keywords:
Ccna, ccnp, exam, certification, pass, free, debug, ip, rip, ospf, ppp, eigrp, igrp, router, Bryant, advantage, 12933, chris

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.

Several factors are considered by OSPF-enabled routers when it comes to forming adjacencies, including hello and dead timer settings. If an adjacency doesn’t form when you think it should, run “debug ip ospf adj”. The reason the adjacency isn’t forming is usually seen quickly with this command’s output.

Let’s not ignore Layer Two! If frame relay mappings are not forming according to your configuration, run “debug frame lmi”. This debug will allow you to quickly diagnose and correct any LMI mismatches.

When it comes to PPP, it can be very frustrating to try to spot a problem with a password or username. Instead of staring at the configuration for 10 minutes, run “debug ppp negotiation” and send a ping over the link. This command will help you spot the router with the misconfigured username or password, not to mention saving you a lot of time!

Effectively using debugs during your CCNA and CCNP exam study will help you truly understand what’s going on “behind the command” – and it will really come in handy on that day when your production network just isn’t doing what you (think) you told it to do!

Share This

You’ve got to know the details of trunks and trunking protocols to earn your CCNA and CCNP. Learn these details from Chris Bryant, CCIE #12933.

Keywords:
cisco, ccna, ccnp, bcmsn, trunking, vlan, native, isl, ieee, dot1q, encapsulation, header, exam

To earn your CCNA or CCNP certification, you’ve got to understand the basics of trunking. This isn’t just a CCNA topic – you must have an advanced understanding of trunking and etherchannels to pass the BCMSN exam and earn your CCNP as well. Before we address those advanced topics, though, you need to master the fundamentals!

A trunk allows inter-VLAN traffic to flow between directly connected switches. By default, a trunk port is a member of all VLANs, so traffic for any and all VLANs can travel across this trunk. That includes broadcast traffic!

The default mode of a switch port does differ between models, so always check your documentation. On Cisco 2950 switches, every single port is in dynamic desirable mode by default, meaning that every port is actively attempting to trunk. On these switches, the only action needed from us is to physically connect them with a crossover cable. In just a few seconds, the port light turns green and the trunk is up and running. The command show interface trunk will verify trunking.

How does the receiving switch know what VLAN the frame belongs to? The frames are tagged by the transmitting switch with a VLAN ID, reflecting the number of the VLAN whose member ports should receive this frame. When the frame arrives at the remote switch, that switch will examine this ID and then forward the frame appropriately.

There are two major trunking protocols you must understand and compare successfully, those being ISL and IEEE 802.1Q. Let’s take a look at the details of ISL first.

ISL is a Cisco-proprietary trunking protocol, making it unsuitable for a multivendor environment. That’s one drawback, but there are others. ISL will place both a header and trailer onto the frame, encapsulating it. This increases the overhead on the trunk line.

You know that the default VLAN is also known as the “native VLAN”, and another drawback to ISL is that ISL does not use the concept of the native VLAN. This means that every single frame transmitted across the trunk will be encapsulated.

The 26-byte header that is added to the frame by ISL contains the VLAN ID; the 4-byte trailer contains a Cyclical Redundancy Check (CRC) value. The CRC is a frame validity scheme that checks the frame’s integrity.

In turn, this encapsulation leads to another potential issue. ISL encapsulation adds 30 bytes total to the size of the frame, potentially making them too large for the switch to handle. (The maximum size for an Ethernet frame is 1518 bytes.)

IEEE 802.1q differs substantially from ISL. In contrast to ISL, dot1q does not encapsulate frames. A 4-byte header is added to the frame, resulting in less overhead than ISL. If the frame is destined for hosts residing in the native VLAN, that header isn’t added. Since the header is only 4 bytes in size, and isn’t even placed on every frame, using dot1q lessens the chance of oversized frames. When the remote port receives an untagged frame, the switch knows that these untagged frames are destined for the native VLAN.

Knowing the details is the difference between passing and failing your CCNA and CCNP exams. Keep studying, get some hands-on practice, and you’re on your way to Cisco certification success!

Share This

As a CCNA and CCNP, you’ve got to be ready for the unexpected. In the field, sometimes you can use the same command on two different devices and get very different results. Learn why, and how to handle this situation, from Chris Bryant, CCIE #12933.

Keywords:
ccna, ccnp, bsci, bcran, free, exam, tutorial, span, tree, protocol, router, switch, ios, 5000

As a CCNA or CCNP, one thing you’ve got to get used to is that change is constant. Cisco regularly issues new IOS versions, not to mention the many different kinds of hardware they produce! While it’s always nice to have “the latest and the greatest” when it comes to routers, switches, firewalls, etc., we have to be prepared for the fact that not all our clients are going to have that latest and greatest!

For instance, there are still quite a few Catalyst 5000 switches out there humming away, and if you’re used to working on IOS-driven switches like the 2950, the same command can have dramatically different results.

Let’s say you’re going to examine the spanning tree protocol (STP) setup of a new client. You’re used to working with newer 2950 switches, and you’ve always run show span on those switches to display spanning-tree information. Then, you run show span on a Catalyst 5000 – and something like this shows:

switch (enable) show span

Destination : Port 6/1

Admin Source : Port 6/2

Oper Source : Port 6/2

Direction : transmit/receive

Incoming Packets: disabled

Learning : enabled

Multicast : enabled

Filter : -

Status : active

Total local span sessions: 1

What’s going on here?

The command show span on a 5000 will not show spanning tree stats – instead, what you’re going to see are statistics relating to Switched Port ANalyzer (SPAN). Surprise!

Consider an example where you’re used to running show span on 5000 switches to see SPAN information. When you run that on a 2950, you know now what you’re going to get – spanning tree information! On a 2950, you’ll need to run show monitor session, followed by the SPAN session number.

SW1#show monitor session 1

Session 1

———

Type : Local Session

Source Ports :

Both : Fa0/1

Destination Ports : Fa0/2

Encapsulation : Native

Ingress: Disabled

As a CCNA and CCNP, this is one of those things you just have to get used to. Commands are going to be different, sometimes radically so, between models. That’s why you need to be adept with both IOS Help and Cisco’s online documentation site. IOS Help is easy, but the online doc site take a little getting used to. Once you learn how to navigate that site, a world of Cisco knowledge is at your fingertips.

Besides, when you sit for the CCIE lab exam, that will be the only friend you have! And a valuable friend it can be – you’re just going to have to trust me on that one.

Share This

Before you study the advanced BGP concepts that the CCNP and CCIE demand, you have to understand the basics. Learn what BGP is used for in the first place from Chris Bryant, CCIE #12933.

Keywords:
cisco, certification, ccnp, bsci, bgp, introduction, what, is, autonomous, system, bryant, 12933

When you’re studying for the BSCI exam on the way to earning your CCNP certification, it’s safe to say that BGP is like nothing you’ve studied to this point. BGP is an external routing protocol used primarily by Internet Service Providers (ISPs). Unless you work for an ISP today or in the future, you may have little or no prior exposure to BGP. Understanding BGP is a great addition to your skill set – and you have to know the basics well to pass the BSCI exam.

Note that I said “the basics”. BGP is a very complex protocol, and when you pursue your CCIE, you’ll see what I’m talking about. As with all things Cisco, though, when broken down into smaller pieces, BGP becomes quite understandable. You will need to know the basics of BGP as presented in this chapter to pass your BSCI exam – so let’s get started.

BGP Defined:

“An Internet protocol that enables groups of routers (called autonomous systems) to share routing information so that efficient, loop-free routes can be established. BGP is commonly used within and between Internet Service Providers (ISPs).”

There are a couple of terms in there that apply to the protocols you’ve mastered so far in your studies. The term “autonomous system” applies to IGRP and EIGRP as well as BGP; you’ll be indicating a BGP AS in your configurations just as you did with IGRP and EIGRP. And we’re always looking for efficient, loop-free routes, right? As it did with IGRP and EIGRP, “autonomous system” simply refers to a group of routers that is managed by a single administrative body. An autonomous system will use an Interior Gateway Protocol (IGP) such as OSPF or EIGRP to route packets inside the AS; outside the AS, an Exterior Gateway Protocol (EGP) such as BGP will be used.

BGP shares some characteristics with some routing protocols you’ve already studied. BGP supports VLSM, summarization, and CIDR. Like EIGRP, BGP will send full updates when two routers initially become neighbors and will send only partial updates after that. BGP does create and maintain neighbor relationships before exchanging routes, and keepalives are sent to keep this relationship alive.

BGP has some major differences from the IGPs we’ve studied to this point. You’ll hear BGP referred to as a path-vector protocol. As opposed to distance-vector protocols that exchange relatively simple information about available routes, BGP routers will exchange extensive information about networks to allow the routers to make more intelligent routing decisions. This additional BGP path information comes in the form of attributes, and these path attributes are contained in the updates sent by BGP routers. Attributes themselves are broken up into two classes, well-known and optional.

BGP also keeps a routing table separate from the IP routing table.
We’ll take a look at BGP attributes in future BSCI tutorials. In the meantime, keep studying!

Share This

When preparing for CCNA and CCNP success, you’ve got to know the many details of OSPF. Learn about these two vital OSPF route types and how they differ from each other in this free tutorial from Chris Bryant, CCIE #12933.

Keywords:
ccnp, bsci, ospf, asbr, e1, e2, route, difference, bryant, 12933, ccna, icnd, intro, pass, exam,free

OSPF is a major topic on both the CCNA and CCNP exams, and it’s also the topic that requires the most attention to detail. Where dynamic routing protocols such as RIP and IGRP have only one router type, a look at a Cisco routing table shows several different OSPF route types.
R1#show ip route
Codes: C – connected, S – static, I – IGRP, R – RIP, M – mobile, B – BGP
D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF external type 1, E2 – OSPF external type 2, E – EGP
In this tutorial, we’ll take a look at the difference between two of these route types, E1 and E2.
Route redistribution is the process of taking routes learned via one routing protocol and injecting those routes into another routing domain. (Static and connected routes can also be redistributed.) When a router running OSPF takes routes learned by another routing protocol and makes them available to the other OSPF-enabled routers it’s communicating with, that router becomes an Autonomous System Border Router (ASBR).
Let’s work with an example where R1 is running both OSPF and RIP. R4 is in the same OSPF domain as R1, and we want R4 to learn the routes that R1 is learning via RIP. This means we have to perform route redistribution on the ASBR. The routes that are being redistributed from RIP into OSPF will appear as E2 routes on R4:
R4#show ip route ospf

O E2 5.1.1.1 [110/20] via 172.34.34.3, 00:33:21, Ethernet0

6.0.0.0/32 is subnetted, 1 subnets

O E2 6.1.1.1 [110/20] via 172.34.34.3, 00:33:21, Ethernet0

172.12.0.0/16 is variably subnetted, 2 subnets, 2 masks

O E2 172.12.21.0/30 [110/20] via 172.34.34.3, 00:33:32,
Ethernet0

O E2 7.1.1.1 [110/20] via 172.34.34.3, 00:33:21, Ethernet0

15.0.0.0/24 is subnetted, 1 subnets

O E2 15.1.1.0 [110/20] via 172.34.34.3, 00:33:32, Ethernet0

E2 is the default route type for routes learned via redistribution. The key with E2 routes is that the cost of these routes reflects only the cost of the path from the ASBR to the final destination; the cost of the path from R4 to R1 is not reflected in this cost. (Remember that OSPF’s metric for a path is referred to as “cost”.)
In this example, we want the cost of the routes to reflect the entire path, not just the path between the ASBR and the destination network. To do so, the routes must be redistributed into OSPF as E1 routes on the ASBR, as shown here.
R1#conf t

Enter configuration commands, one per line. End with CNTL/Z.

R1(config)#router ospf 1

R1(config-router)#redistribute rip subnets metric-type 1

Now on R4, the routes appear as E1 routes and have a larger metric, since the entire path cost is now reflected in the routing table.
O E1 5.1.1.1 [110/94] via 172.34.34.3, 00:33:21, Ethernet0

6.0.0.0/32 is subnetted, 1 subnets

O E1 6.1.1.1 [110/100] via 172.34.34.3, 00:33:21, Ethernet0

172.12.0.0/16 is variably subnetted, 2 subnets, 2 masks

O E1 172.12.21.0/30 [110/94] via 172.34.34.3, 00:33:32, Ethernet0

O E1 7.1.1.1 [110/94] via 172.34.34.3, 00:33:21, Ethernet0

15.0.0.0/24 is subnetted, 1 subnets

O E1 15.1.1.0 [110/94] via 172.34.34.3, 00:33:32, Ethernet0

Knowing the difference between E1 and E2 routes is vital for CCNP exam success, as well as fully understanding a production router’s routing table. Good luck in your studies!

Share This

You know the Frame LMI is a keepalive, but did you know that Frame offers an end-to-end keepalive as well? Learn these vital exam details from Chris Bryant, CCIE #12933.

Keywords:
ccna, ccnp, frame, relay, keepalive, end, to, exam, pass, free, tutorial, pvc, svc, map, chris, ccie

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.

Reply mode enables only the receive process. The router will respond to requests from other routers but will initiate no requests of its own.

Finally, passive reply mode allows the router to respond to requests, but no timers are set and no events are tracked.

Frame Relay End-To-End Keepalive defaults:

Two send or receive errors must be registered in order for the VC to be considered down.

The event window size is three. The event window is the number of events considered by the router when determining the status of the VC. Therefore, using the defaults, two send or receive errors would have to be received within the event window of three events for the VC to be considered down.

The timer mentioned earlier – the amount of time a router waits for a response – is set to 10 seconds

Working with Frame Relay end-to-end keepalives is just one Frame skill you’ll need to pass the CCNP exams – and I wouldn’t be surprised to see them on a CCIE exam. Know the details and you’re on your way to Cisco certification exam success!

Share This

Dialer Watch is an important topic on your Cisco certification exams, but there are common errors you must avoid in order to pass the exams. Learn all about Dialer Watch from Chris Bryant, CCIE #12933.

Keywords:
cisco, ccna, ccnp, dialer, watch, isdn, pass, free, exam, certification, router, switch

Dialer Watch is a vital part of your CCNA and CCNP studies, particularly for the BCRAN exam, but it’s one of the most misunderstood technologies as well. To help you pass the CCNA and CCNP certification exams, here’s a detailed look at Dialer Watch.

Dialer Watch allows you to configure a route or routes as “watched” when the watched route leaves the routing table and there is no other valid route to that specific destination, the ISDN link will come up. In the following example, R1 and R2 are connected by both a Frame Relay cloud over the 172.12.123.0 /24 network and an ISDN cloud using the 172.12.12.0 /24 network. The routers are running OSPF over the Frame cloud, and R1 is advertising its loopback of 1.1.1.1/32 as well as an Ethernet segment, 10.1.1.0/24, via OSPF. R2 has both of these routes in its OSPF table, as shown below.

R2#show ip route ospf

1.0.0.0/32 is subnetted, 1 subnets

O 1.1.1.1 [110/65] via 172.12.123.1, 00:00:07, Serial0

10.0.0.0/24 is subnetted, 1 subnets

O 10.1.1.0 [110/128] via 172.12.123.1, 00:00:08, Serial0

We want R2 to place a call to R1 if either the loopback or Ethernet networks leave R2’s routing table, but we don’t want to have to depend on interesting traffic. That dictates the use of Dialer Watch.

First, configure the list of watched routes with dialer watch-list. Only one of the watched routes needs to leave the routing table for the ISDN link to come up. In this example, R2 will watch both routes from its OSPF routing table.

Be careful with this command. The entries here need to match exactly the routes and masks being watched. Dialer watch-lists use subnet masks, not wildcard masks.

R2(config)#dialer watch-list 5 ip 10.1.1.0 255.255.255.0

R2(config)#dialer watch-list 5 ip 1.1.1.1 255.255.255.255

Configure the dialer watch-group command on the BRI interface, AND frame map statements for the watched routes. As with dialer-list and dialer-group, the group number referenced in the dialer watch-group command must match the number assigned to the dialer watch-list.

The Dialer Watch configuration will not work without frame map statements for each watched route. I repeat this because this is the step a lot of people leave out.

R2(config)#interface bri0

R2(config-if)#dialer watch-group 5

R2(config-if)# dialer map ip 1.1.1.1 255.255.255.255. name R1 5557777 broadcast

R2(config-if)# dialer map ip 10.1.1.0 255.255.255.0 name R1 5557777 broadcast

To test Dialer Watch, the Serial0 interface on R2 will be shut down. Since we’re running OSPF, the route table will be updated almost immediately and the ISDN link should come up right after that.

R2(config)#int s0

R2(config-if)#shut

01:12:47: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.1 on Serial0 from FULL to DOWN, N
eighbor Down: Interface down or detached

01:12:47: %LINK-3-UPDOWN: Interface BRI0:1, changed state to up

01:12:48: %SYS-5-CONFIG_I: Configured from console by console

01:12:48: %LINEPROTO-5-UPDOWN: Line protocol on Interface BRI0:1, changed state
to up

01:12:49: %LINK-5-CHANGED: Interface Serial0, changed state to administratively
down

01:12:50: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0, changed state
to down

01:12:53: %ISDN-6-CONNECT: Interface BRI0:1 is now connected to 5557777 R1

Within five seconds, the ISDN link is up. show dialer verifies that Dialer Watch is the reason the line was brought up.

R2#show dialer

BRI0 – dialer type = ISDN

Dial String Successes Failures Last DNIS Last status

5557777 2 0 00:00:11 successful

0 incoming call(s) have been screened.

0 incoming call(s) rejected for callback.

BRI0:1 – dialer type = ISDN

Idle timer (120 secs), Fast idle timer (20 secs)

Wait for carrier (30 secs), Re-enable (15 secs)

Dialer state is data link layer up

Dial reason: Dialing on watched route loss

Time until disconnect 108 secs

Connected to 5557777 (R1)
A final note regarding Dialer Watch … it will not work with RIP, but will with all our other dynamic IGPs (IGRP, EIGRP, OSPF).

Share This

To pass your CCNA and CCNP exams, you’ve got to have a plan for success. Learn how to create an unbeatable study plan from Chris Bryant, CCIE #12933.

Keywords:
Ccna, ccnp, pass, exam, study, plan, Bryant, advantage, chris, router, switch, network, cisco, certification

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!

Share This

To pass the BCMSN exam and earn your CCNP certification, you’ve got to know how the HSRP MAC address is arrived at, and how to change it! Learn both from Chris Bryant, CCIE #12933.

Keywords:
Ccnp, certification, cisco, hsrp, mac, address, standby, switch, multilayer, router, bcmsn

To pass the BCMSN exam and earn your CCNP, you’ve got to know HSRP inside and out! Part of that is knowing how the MAC address of the virtual router is derived, and another part is knowing how to change this address. We’ll look at both features in this tutorial.

We’ve got two routers on a segment running HSRP, so first we need to find out what the MAC address of the HSRP virtual router is. The show command for HSRP is show standby, and it’s the first command you should run while configuring and troubleshooting HSRP. Let’s run it on both routers and compare results.

R2#show standby

Ethernet0 – Group 5

Local state is Standby, priority 100

Hellotime 3 sec, holdtime 10 sec

Next hello sent in 0.776

Virtual IP address is 172.12.23.10 configured

Active router is 172.12.23.3, priority 100 expires in 9.568

Standby router is local

1 state changes, last state change 00:00:22

R3#show standby

Ethernet0 – Group 5

Local state is Active, priority 100

Hellotime 3 sec, holdtime 10 sec

Next hello sent in 2.592

Virtual IP address is 172.12.23.10 configured

Active router is local

Standby router is 172.12.23.2 expires in 8.020

Virtual mac address is 0000.0c07.ac05

2 state changes, last state change 00:02:08

R3 is in Active state, while R2 is in Standby. The hosts are using the 172.12.123.10 address as their gateway, but R3 is actually handling the workload. R2 will take over if R3 becomes unavailable.

An IP address was statically assigned to the virtual router, but not a MAC address. However, there is a MAC address under the show standby output on R3, the active router. How did the HSRP process arrive at a MAC of 00-00-0c-07-ac-05?

Well, most of the work is already done before the configuration is even begun. The MAC address 00-00-0c-07-ac-xx is reserved for HSRP, and xx is the group number in hexadecimal. That’s a good skill to have for the exam, so make sure you’re comfortable with hex conversions. The group number is 5, which is expressed as 05 with a two-bit hex character. If the group number had been 17, we’d see 11 at the end of the MAC address – one unit of 16, one unit of 1.

On rare occasions, you may have to change the MAC address assigned to the virtual router. This is done with the standby mac-address command. Just make sure you’re not duplicating a MAC address that’s already on your network!

R2(config-if)#standby 5 mac-address 0000.1111.2222

1d12h: %STANDBY-6-STATECHANGE: Ethernet0 Group 5 state Active -> Learn

R2#show standby

Ethernet0 – Group 5

Local state is Active, priority 150, may preempt

Hellotime 4 sec, holdtime 12 sec

Next hello sent in 3.476

Virtual IP address is 172.12.23.10 configured

Active router is local

Standby router is 172.12.23.3 expires in 10.204

Virtual mac address is 0000.1111.2222 configured

4 state changes, last state change 00:00:00

1d12h: %STANDBY-6-STATECHANGE: Ethernet0 Group 5 state Listen -> Active

The MAC address will take a few seconds to change, and the HSRP routers will go into Learn state for that time period.

A real-world HSRP troubleshooting note: If you see constant state changes with your HSRP configuration, do what you should always do when troubleshooting – check the physical layer first. Best of luck on your BCMSN exam!

Share This

Many CCNA and CCNP candidates hear about “reverse telnet”, but aren’t quite sure what it is. Learn what it is, how it works, and how to configure it in this free Cisco tutorial from Chris Bryant, CCIE #12933.

Keywords:
ccna,ccnp,free,tutorial,pass,home, lab, reverse, telnet, access, server,exam,router,switch,cisco,bsci,cit,bcran,configure,ebook,chris,Bryant,ccie,12933,advantage

Occasionally, during your CCNA and CCNP studies, you’ll run into a term that just doesn’t quite make sense to you. (Okay, more than occasionally!) One such term is “reverse telnet”. As a Cisco certification candidate, you know that telnet is simply a protocol that allows you to remotely connect to a networking device such as a router or switch. But what is “reverse telnet”, and why is it so important to a Cisco CCNA / CCNP home lab setup?

Where a telnet session is started by a remote user who wants to remotely control a router or switch, a reverse telnet session is started when the host device itself imitates the telnet session.

In a CCNA / CCNP home lab, reverse telnet is configured and used on the access server. The access server isn’t a white box server like most of us are used to; an access server is a Cisco router that allows you to connect to multiple routers and switches with one session without having to move a rollover cable from device to device.

Your access server will use an octal cable to connect to the other routers and switches in your home lab. The octal cable has one large serial connector that will connect to the access server, and eight rj-45 connectors that will connect to your other home lab devices. Your access server then needs an IP Host table in order to perform reverse telnet.

An IP Host table is easy to put together (and you better know how to write one to pass the CCNA!). The IP Host table is used for local name resolution, taking the place of a DNS server. A typical access server IP Host table looks like this:

ip host FRS 2007 100.1.1.1

ip host R3 2003 100.1.1.1

ip host R1 2001 100.1.1.1

ip host R2 2002 100.1.1.1

ip host R4 2004 100.1.1.1

ip host R5 2005 100.1.1.1

ip host SW1 2006 100.1.1.1

interface Loopback0

ip address 100.1.1.1 255.255.255.255

no ip directed-broadcast

This configuration will allow you to use your access server to connect to five routers, a frame relay switch, and a switch without ever moving a cable. When you type “R1″ at the console line, for example, you’ll be connected to R1 via reverse telnet. If you have a smaller lab, an access server is still a real timesaver and an excellent investment. And by getting a static IP address to put on your access server, you can even connect to your home lab from remote locations!

Share This