CCNA / CCNP Cisco Certification Exam: Frame Relay Encapsulation Types

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.

 CCNA / CCNP Cisco Certification Exam:  Frame Relay Encapsulation Types

CCNA / CCNP Cisco Certification Exam: Caller ID Screening And Callback

To pass Cisco certification exams, you have to know more than one way to do things.  Learn another method of configuring ISDN callback from Chris Bryant, CCIE #12933.

CCNA / CCNP Cisco Certification Exam:  Caller ID Screening And Callback

CCNA / CCNP Cisco Certification Exam: Cabling Your Home Lab

Putting together a Cisco home lab is a great idea, but sometimes choosing the right cabling can be a little confusing.  Learn the details from Chris Bryant, CCIE #12933.

Exam Essentials Questions and Answers

Exam Essentials
Know the differences among leased lines, circuit switching, and packet switching. A leased
line is a dedicated connection, a circuit switched connection is like a phone call and can be on
or off, and packet switching is essentially a connection that looks like a leased line but is priced
more like a circuit-switched connection.
Understand the different WAN protocols. Pay particular attention to HDLC, Frame Relay,
and PPP. HDLC is the default encapsulation on Cisco routers, PPP provides an industry-standard
way of encapsulating multiple routed protocols across a link and must be used when connecting
equipment from multiple vendors. Frame relay is a packet-switched technology that can offer cost
advantages over leased lines but has more complex configuration options.

Exam Essentials Questions and Answers

Review Questions
1. Which of the following allows a router to respond to an ARP request that is intended for a
remote host?
A. Gateway DP
B. Reverse ARP (RARP)
C. Proxy ARP
D. Inverse ARP (IARP)
E. Address Resolution Protocol (ARP)
2. You want to implement a mechanism that automates the IP configuration, including IP
address, subnet mask, default gateway, and DNS information. Which protocol will you use
to accomplish this?
A. SMTP
B. SNMP
C. DHCP
D. ARP
3. Which class of IP address provides a maximum of only 254 host addresses per network ID?
A. Class A
B. Class B
C. Class C
D. Class D
E. Class E
4. Which of the following describe the DHCP Discover message? (Choose two.)
A. It uses FF:FF:FF:FF:FF:FF as a layer 2 broadcast.
B. It uses UDP as the Transport layer protocol.
C. It uses TCP as the Transport layer protocol.
D. It does not use a layer 2 destination address.
5. What are two charcterisitics of Telnet (choose 2)?
A. It send data in clear text format
B. It is a protocol designed and used only by Cisco routers
C. It is more secure then using Secure Shell (SSH)
D. You must purchase Telnet from Microsoft
E. It requires the destiatnion device be confiugre to support Telnet services and connections
6. Which of the following services use UDP? (Choose three.)
A. DHCP
B. SMTP
C. SNMP
D. FTP
E. HTTP
F. TFTP
7. Which of the following are TCP/IP protocols used at the Application layer of the OSI model?
(Choose three.)
A. IP
B. TCP
C. Telnet
D. FTP
E. TFTP
8. When data is encapsulated, which is the correct order?
A. Data, frame, packet, segment, bit
B. Segment, data, packet, frame, bit
C. Data, segment, packet, frame, bit
D. Data, segment, frame, packet, bit
9. Which two statements about a reliable connection-oriented data transfer are true?
A. Receiving hosts acknowledge receipt of data.
B. When buffers are full, packets are discarded and are not retransmitted.
C. Windowing is used to provide flow control and unacknowledged data segments.[
D. If the transmitting host’s timer expires before receipt of an acknowledgment, the transmitting
host drops the virtual circuit.
10. Which of the following describe router functions? (Choose four.)
A. Packet switching
B. Collision prevention
C. Packet filtering
D. Broadcast domain enlargement
E. Internetwork communication
F. Broadcast forwarding
G. Path selection
Answers to Review Questions
1. C. Proxy ARP can help machines on a subnet reach remote subnets without configuring
routing or a default gateway.
2. C. Dynamic Host Configuration Protocol (DHCP) is used to provide IP information to hosts
on your network. DHCP can provide a lot of information, but the most common is IP address,
subnet mask, default gateway, and DNS information.
3. C. A Class C network address has only 8 bits for defining hosts: 28 – 2 = 254.
4. A, B. A client that sends out a DHCP Discover message in order to receive an IP address
sends out a broadcast at both layer 2 and layer 3. The layer 2 broadcast is all Fs in hex, or
FF:FF:FF:FF:FF:FF. The layer 3 broadcast is 255.255.255.255, which means all networks and
all hosts. DHCP is connectionless, which means it uses User Datagram Protocol (UDP) at the
Transport layer, also called the Host-to-Host layer.
5. A, E. Telnet has been around as long as networking and there is no cost to implement Telnet
services on your network. However, all data is sent in a clear text format and both the sending
and receving devices must have telnet services running.
6. A, C, F. DHCP, SNMP, and TFTP use UDP. SMTP, FTP, and HTTP use TCP.
7. C, D, E. Telnet, File Transfer Protocol (FTP), and Trivial FTP (TFTP) are all Application layer
protocols. IP is a Network layer protocol. Transmission Control Protocol (TCP) is a Transport
layer protocol.
8. C. The encapsulation method is data, segment, packet, frame, bit.
9. A, C. When a virtual circuit is created, windowing is used for flow control and acknowledgment
of data.
10. A, C, E, G. Routers provide packet switching, packet filtering, internetwork communication,
and path selection.

Identify and correct common network problems

Troubleshooting IP addressing is obviously an important skill because running into trouble
somewhere along the way is pretty much a sure thing, and it’s going to happen to you. No—
I’m not a pessimist; I’m just keeping it real. Because of this nasty fact, it will be great when you
can save the day because you can both figure out (diagnose) the problem and fix it on an IP
network whether you’re at work or at home!

Identify and correct common network problems 

So this is where I’m going to show you the “Cisco way” of troubleshooting IP addressing.
Let’s go over the troubleshooting steps that Cisco uses first. These are pretty simple, but
important nonetheless. Pretend that you’re at a customer host and they’re complaining that
their host cannot communicate to a server, which just happens to be on a remote network.
Here are the four troubleshooting steps that Cisco recommends:

CCNA / CCNP Cisco Certification Exam: Attending A Video Boot Camp

Not every CCNA and CCNP candidate has thousands of dollars to spend on a boot camp.  Learn how to get the same quality training for less money and travel from Chris Bryant, CCIE #12933.

CCNA / CCNP Cisco Certification Exam:  Attending A Video Boot Camp

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

CCNP Certification: How And Why To Build An Etherchannel

Etherchannels are in use all over the world, as well as on your CCNA and CCNP exams.  Learn how to build and support an EC in this tutorial from Chris Bryant, CCIE #12933.

 CCNP Certification: How And Why To Build An Etherchannel

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

Introduction To BGP Attributes|Cisco CCNA / CCNP Certification

BGP is one of the most complex topics you’ll tackle in your CCNP studies, but if you break it down to the fundamentals, you’ll pick it up quickly.  Chris Bryant, CCIE #12933, has written this free BGP tutorial on BGP attributes to help you do master BGP and pass the exams!

 Introduction To BGP Attributes|Cisco CCNA / CCNP Certification

 

BGP is one of the most complex topics you'll study when pursuing your CCNP, if not the most complex. I know from personal experience that when I was earning my CCNP, BGP is the topic that gave me the most trouble at first. One thing I keep reminding today's CCNP candidates about, though, is that no Cisco technology is impossible to understand if you just break it down and understand the basics before you start trying to understand the more complex configurations.

Cisco CCNA / CCNP / BCMSN Exam Review: Trunking And Trunking Protocols

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.

Cisco CCNA / CCNP / BCMSN Exam Review:  Trunking And Trunking Protocols

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!

Get Cisco CCNA / CCNP Certification|OSPF E2 vs. E1 Routes

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.

Get Cisco CCNA / CCNP Certification|OSPF E2 vs. E1 Routes

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

CCNP Certification Exam |Floating Static Routes on cisco

Cisco CCNA  / CCNP Certification Exam Tutorial:  Floating Static Routes

Knowing when and how to configure floating static routes is an important skill on your Cisco certification exams, as well as working in real-world networks.  Learn all about floating static routes from Chris Bryant, CCIE #12933.

CCNP Certification Exam |Floating Static Routes on cisco

 

CCNP Certification / BCMSN Exam Tutorial: Server Load Balancing (SLB)

CCNP Certification / BCMSN Exam Tutorial:  Server Load Balancing (SLB)

You need to know all about router redundancy strategies to become a CCNP, but there's an important server redundancy feature you need to know as well!  Learn all about Server Load Balancing from Chris Bryant, CCIE #12933.


When you're working on your BCMSN exam on your way to CCNP certification, you'll read at length about how Cisco routers and multilayer switches can work to provide router redundancy - but there's another helpful service, Server Load Balancing, that does the same for servers. While HSRP, VRRP, and CLBP all represent multiple physical routers to

CCNP Certification / BCMSN Exam Tutorial: QoS Service Types

CCNP Certification / BCMSN Exam Tutorial:  QoS Service Types

To earn your CCNP certification, you've got to know how the different QoS service types operate.  Learn the basics from Chris Bryant, CCIE #12933.:


To pass the CCNP exams, you’ve got to master Quality of Service, and the first step in doing so is knowing the differences between the different QoS types.

Now this being Cisco, we can't just have one kind of QoS! We've got best-effort delivery, Integrated Services, and Differentiated Services. Let's take a quick look at all three.

CCNP Certification / BCMSN Exam Tutorial: HSRP MAC Addresses And Timers

CCNP Certification / BCMSN Exam Tutorial:  HSRP MAC Addresses And Timers

Just a few of the HSRP details you must know to earn your CCNA are configuring a MAC address for the virtual router.  Learn how to do so from Chris Bryant, CCIE #12933.

To earn your CCNP certification and pass the BCMSN exam, you've got to know what HSRP does and the many configurable options.  While the operation of HSRP is quite simple (and covered in a previous tutorial), you also need to know how HSRP arrives at the MAC address for the virtual router - as well as how to configure a new MAC for this virtual router.  This puts us in the unusual position of creating a physical address for a router that doesn't exist!

The output of show standby for a two-router HSRP configuration is shown below.

R2#show standby

CCNP / BSCI Exam Tutorial: Route Summarization And The OSPF Null Interface

CCNP / BSCI Exam Tutorial:  Route Summarization And The OSPF Null Interface

Route summarization requires a knowledge of binary conversion, as well as knowing how each protocol responds to summarization.  Learn how OSPF does so from Chris Bryant, CCIE #12933.

CCNP exam success, particularly on the BSCI exam, demands you understand the details of route summarization.  This skill not only requires that you have a comfort level with binary conversions, but you have to know how and where to apply route summarization with each individual protocol.

You also have to know the "side effects" of route summarization.  With OSPF, there will actually be an extra interface created at the point of summarization, and this catches a lot of CCNP candidates by surprise.  Let's take a look at the null0 interface and how it relates to OSPF summarization.

On R1, the following networks are redistributed into OSPF, and then summarized.

interface Loopback16

 ip address 16.16.16.16 255.0.0.0


interface Loopback17

 ip address 17.17.17.17 255.0.0.0


interface Loopback18

 ip address 18.18.18.18 255.0.0.0

interface Loopback19

 ip address 19.19.19.19 255.0.0.0

R1(config)#router ospf 1

R1(config-router)#redistribute connected subnets

R1(config-router)#summary-address 16.0.0.0 252.0.0.0

The summary address appears on R2, a downstream router.

R2#show ip route ospf


O E2 16.0.0.0/6 [110/20] via 172.12.123.1, 00:00:05, Serial0


Let's go back to R1 and look at its OSPF table.

R1#show ip route ospf


O    16.0.0.0/6 is a summary, 00:01:51, Null0

Where did the null0 interface come from, and why is it there?  Packets sent to the null interface are dropped, and in this case, that's a good thing.

When you configure summary routes in OSPF, a route to null0 will be installed into the OSPF routing table.  This helps to prevent routing loops.  Any packets destined for the routes that have been summarized will have a longer match in the routing table, as shown below...

C    17.0.0.0/8 is directly connected, Loopback17

C    16.0.0.0/8 is directly connected, Loopback16

C    19.0.0.0/8 is directly connected, Loopback19

C    18.0.0.0/8 is directly connected, Loopback18

O  16.0.0.0/6 is a summary, 00:01:51, Null0


.. and packets that do not match one of the summarized routes but do match the summary route will be dropped.

Preventing routing loops when performing route redistribution and summarization is vital.  OSPF gives us a little help in that regard in this situation, and as you study more complex redistribution scenarios on your way to the CCNP and CCIE, you'll realize that we'll take all the help we can get!

CCNP Certification / BCMSN Exam Tutorial: Getting Started With HSRP

CCNP Certification / BCMSN Exam Tutorial:  Getting Started With HSRP

HSRP seems simple enough, but there are a lot of options you need to know to pass the CCNP exams!  Learn how to get started with HSRP from Chris Bryant, CCIE #12933.


Defined in RFC 2281, HSRP is a Cisco-proprietary protocol in which routers are put into an HSRP router group. Along with dynamic routing protocols and STP, HSRP is considered a high-availability network service, since all three have an almost immediate cutover to a secondary path when the primary path is unavailable.

VLAN Trunking Protocol (VTP)|CCNP / BCMSN Exam Tutorial

BCMSN exam

To pass the BCMSN exam, you’ve got to know the ins and outs of VTP.  Review the basics and get ready for CCNP exam success with Chris Bryant, CCIE #12933.


Passing the BCMSN exam and getting one step closer to the CCNP certification means learning and noticing details that you were not presented with in your CCNA studies. (Yes, I know – you had more than enough details then, right?)   One protocol you’ve got to learn more details about is VTP, which seemed simple enough in your CCNA studies!  Part of learning the details is mastering the fundamentals, so in this tutorial we’ll review the basics of VTP.

CCNA Certification Exam Tutorial: Cisco Switching Modes

CCNA Certification Exam Tutorial:  Cisco Switching Modes

An often-overlooked part of CCNA studies is learning the different modes a Cisco switch can run.  Learn these vital exam details from Chris Bryant, CCIE #12933.


To pass the CCNA exam and earn this important certification, you’ve got to know switching inside and out.  While you’re learning all the basic switching theory, make sure to spend some time with the one of three switching modes Cisco routers can use.

Store-and-Forward is exactly what it sounds like.  The entire frame will be stored before it is forwarded.  This mode allows for the greatest amount of error checking, since a CRC (Cyclical Redundancy Check) is run against the frame before it is forwarded.  If the frame contains an error, it is discarded.  If there’s no problem with the frame, the frame is then forwarded to its proper destination.


While store-and-forward does perform error checking, the delay in processing the frame while this error check is run results in higher latency than the other modes you’re about to read about.  The latency time can also vary, since not all frames are the same size.

Cut-through switching copies only the destination MAC address into its memory before beginning to forward the frame.  Since the frame is being forwarded as soon as the destination MAC is read, there is less latency than store-and-forward.  The drawback is that there is no error checking.

There is a middle ground, fragment-free switching.  Only part of the frame is copied to memory before it is forwarded, but it’s the first 64 bytes of the frame, not just the destination MAC.  (Why?  Because if there is a problem with the frame, it’s most likely in the first 64 bytes.)  There is a little more error checking than cut-through, but not as much latency as with store-and-forward. 

Note that the latency of both cut-through and fragment-free is fixed; these modes always look at the first six or 64 bytes, respectively.  Store-and-forward's latency depends on the size of the frame.
Learning the similarities and differences between these modes is an often-overlooked part of CCNA studies.   Spend some time studying this important CCNA topic – you’ll be glad you did!

CCNP / BCMSN Exam Tutorial: VLAN Trunking Protocol (VTP)

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CCNP BCMSN Exam Cram 2 (Exam Cram 642-811)

To pass the BCMSN exam, you’ve got to know the ins and outs of VTP.  Review the basics and get ready for CCNP exam success with Chris Bryant, CCIE #12933.

Passing the BCMSN exam and getting one step closer to the CCNP certification means learning and noticing details that you were not presented with in your CCNA studies. (Yes, I know – you had more than enough details then, right?)   One protocol you’ve got to learn more details about is VTP, which seemed simple enough in your CCNA studies!  Part of learning the details is mastering the fundamentals, so in this tutorial we’ll review the basics of VTP.


In show vtp status readouts, the "VTP Operating Mode" is set to "Server" by default.  The more familiar term for VTP Operating Mode is simply VTP Mode, and Server is the default.  It's through the usage of VTP modes that we can place limits on which switches can delete and create VLANs.

In Server mode, a VTP switch can be used to create, modify, and delete VLANs.  This means that a VTP deployment has to have at least one switch in Server mode, or VLAN creation will not be possible.  Again, this is the default setting for Cisco switches.

Switches running in Client mode cannot be used to create, modify, or delete VLANs. Clients do listen for VTP advertisements and act accordingly when VTP advertisements notify the Client of VLAN changes.

VTP Transparent mode actually means that the switch isn't participating in the VTP domain as Servers and Clients do.  (Bear with me here.)  Transparent VTP switches don't synchronize their VTP databases with other VTP speakers. They don't even advertise their own VLAN information!  Therefore, any VLANs created on a Transparent VTP switch will not be advertised to other VTP speakers in the domain, making them locally significant only. (I know you remember that phrase from your CCNA studies!)

Devices running VTP Transparent mode do have a little something to do with the other switches in the VTP domain, though.  When a switch running in Transparent mode receives a VTP advertisement, that switch will forward that advertisement to other switches in that VTP domain.

Configuring switches as VTP Clients is a great way to “tie down” VLAN creation capabilities to switches that are under your physical control.  However, this occasionally leads to a situation where only the VTP clients will have ports that belong to a given VLAN, but the VLAN still has to be created on the VTP server.  (VLANs can be created and deleted in transparent mode, but those changes aren't advertised to other switches in the VTP domain.)


In the next BCMSN tutorial, we’ll take a look at the details of VTP.

CCNA / MCSE / CCNP Certification: Creation Failure Work for You

CCNA / MCSE / CCNP Certification:  creation Failure Work for You

Failing an exam isn't the end of the world. It's happened to all of us, and you can make this failure work for you. Learn how from Chris Bryant, CCIE #12933.

Whether you're on the road to the CCNA, CCNP, MCSE, or you're on any other computer certification track, the odds are that sooner or later, you're going to fail an exam.  It's happened to almost all of us, yours truly included.   What you have to keep in mind in these times is that success is not a straight line.  You've probably seen charts showing the growth of an industry or a business -- you know, the ones that go from left to right, and look kind of jagged.  The line goes up for a while, then down a bit, then up some more, then down a little. 

The key?  While every business has its setbacks, the net result is that the line goes up and progress is made.  That's how you want your certification pursuit and your career to go as well - upward!

I'm not asking you to be happy about failing an exam.  You're allowed to get mad for a few minutes, vow to never take another exam again, and be disappointed.  What you're not allowed to do is stay that way. 

If you put your books away in a fit of anger, get them out.  If you took some time off, it's time to get back to work.  Again, there's nothing wrong with being unhappy about failing an exam.  It's how you handle that failure that counts.  No inventor, executive, or entrepreneur has ever been right 100% of the time.  Learn something from your failure.   Was your study time quality study time?  Did you get some hands-on practice with the technology you're studying?  Asking yourself these questions can be tough, but it can be highly valuable in making sure you don't fail the next time.  And there must be a next time - because the one thing you cannot do is quit.

Besides, take it from someone who's been there - your temporary failure makes your eventual success that much sweeter.


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Free CCNA / CCNP Home Lab Tutorial: The VLAN.DAT File

Free CCNA / CCNP Home Lab Tutorial:  The VLAN.DAT File

CCNA and CCNP candidates are often confused about why VLANs and VTP information is still present on a switch after the configuration is erased.  Learn why this happens and how to really delete VLAN information in this free tutorial from Chris Bryant, CCIE #12933.

CCNA and CCNP candidates who have their own Cisco home labs often email me about an odd situation that occurs when they erase a switch's configuration.  Their startup configuration is gone, as they expect, but the VLAN and VTP information is still there!

Sounds strange, doesn't it?   Let's look at an example.  On SW1, we run show vlan brief and see in this abbreviated output that there are three additional vlans in use:

SW1#show vlan br


10   VLAN0010                         active

20   VLAN0020                         active

30   VLAN0030                         active

We want to totally erase the router's startup configuration, so we use the write erase command, confirm it, and reload without saving the running config:

SW1#write erase

Erasing the nvram filesystem will remove all configuration files! Continue?

[confirm]

[OK]

Erase of nvram: complete


00:06:00: %SYS-7-NV_BLOCK_INIT: Initalized the geometry of nvram

SW1#reload

System configuration has been modified. Save? [yes/no]: n

Proceed with reload? [confirm]

The router reloads, and after exiting setup mode, we run show vlan brief again.  And even though the startup configuration was erased, the vlans are still there!

Switch#show vlan br


10   VLAN0010                         active

20   VLAN0020                         active

30   VLAN0030                         active

The reason is that this vlan and VTP information is actually kept in the VLAN.DAT file in Flash memory, and the contents of Flash are kept on a reload.  The file has to be deleted manually.

There's a little trick to deleting this file.  The switch will prompt you twice to ask if you really want to get rid of this file. Don't type "y" or "yes"; just accept the defaults by hitting the return key.  If you type "y", the router attempts to delete a file named "y", as shown here:

Switch#delete vlan.dat

Delete filename [vlan.dat]? y

Delete flash:y? [confirm]

%Error deleting flash:y (No such file or directory)



Switch#delete vlan.dat

Delete filename [vlan.dat]?

Delete flash:vlan.dat? [confirm]


Switch#

The best way to prepare for CCNA and CCNP exam success is by working on real Cisco equipment, and by performing lab tasks over and over.  Repetition is the mother of skill, and by truly erasing your VLAN and VTP information by deleting the vlan.dat file from Flash, you'll be building your Cisco skills to the point where your CCNA and CCNP exam success is a certainty.

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CCNA / CCNP Home Lab lesson: assemble Your Cisco Home Lab

 At what time you're putting as one your Cisco home lab, you have a group of models to choose from!  Chris Bryant, CCIE #12933, shows you how he's built his CCNA / CCNP home labs and offers tips on purchasing your own Cisco routers.

Cisco Home Lab