Simulation Router & Switch

Network Simulation By Program Boson NetSim

Simulation Router

Dowload Program Boson NetSim

1. The first, you click start program : start/programs/Boson Software/

Boson Netsim for CCNA/Boson Netsim : it show below

Close window "Boson Lab Navigator".

2. Click NetMap : it show below

Devices and Connecters you double click

Available Router/2500 Series/2501 : it show below

Wondow Set Device Name you can selece Create name "Telecom"

for Router1 and Create name "CCNA" for Router2 : it show below

3. On Router "Telecom" you Right Click Add Connection to:/Serial 0/

Pop up "Select Serial Connection Type"

you select Point to Point Serial connection (Serial Cable) : it show below

Click Next it show New Connection window

Available Devices you select CCNA

Serial Interfaces select ethernet 0

next Click Finesh :it show below

Serial Connection-Cable Select Window

you select Telecom,Serial 0 Next Click OK : it show below

4. Boson Nework Designer Window

Click File/Load NetMap into the Simmulator : it show below

You can config Router this Window

- Securing Routers and Switches

Securing Routers and Switches

In CCNA land, security is an increasing concern. CCNA will not make you a security expert, but you will learn the very basics of good networking security and a little about how to apply them.
Initially, your router or switch will have no passwords at all; pressing Enter will grant you first User EXEC, then Privileged EXEC access by using the enable command. The Telnet lines are secured by default—they will refuse connections until they are configured with a password.

The minimum security configuration would be to require a password to log in to your devices. Passwords can be applied to the console port, to the VTY lines (controlling Telnet/SSH access), and to the Privileged EXEC prompt.

The following commands illustrate how to apply basic password security to your router or switch, for the console port (User EXEC), VTY lines (for remote User EXEC administration using Telnet), and the Privileged EXEC prompt. Lines that begin with an exclamation point are informational remarks and do not configure the device:

Router(config)#line con 0
! The console port is always con 0
Router(config-line)#login
! Requires a password to access User Exec over the console port
Router(config-line)#password TelecomCCNA
! Specifies the password - Note: passwords are case-sensitive.
Router(config)#line vty 0 4
! There are 5 VTY lines, numbered 0 through 4
Router(config-line)#login
Router(config-line)#password 23StanleyCups !
Router(config)#enable password cisco
! sets the Privileged Exec password to 'cisco'


Note

A word about VTY lines: A VTY line is used by both Telnet and SSH connections. The "V" in VTY stands for Virtual, because there is no associated hardware as there would be with the Console port or asynchronous serial (TTY) ports for modems. For our purposes, there are five VTY lines, numbered 0, 1, 2, 3 and 4. The command line vty 0 4 shown previously allows you to configure all of them at once by specifying the range of "0 [through] 4". Some newer switches and routers will show 16 lines, numbered 0 through 15; it's unlikely that this feature will be a factor on your test, however.

Why have so many VTY lines, when only one is used by a Telnet session? For that same reason, actually: One Telnet/SSH session uses one VTY line. If you Telnet in, then Telnet out to some other device, you use 2 VTY lines. It's common to Telnet to multiple devices concurrently when you are working on a network; it's also possible that multiple admins could be working on or from the same device at the same time, each admin needing at least one VTY line.

By the way, there is no easy way to determine or predict which VTY line you are going to connect to.
They are used in a round-robin fashion, so setting a different password for each one is probably more of a hassle than a security benefit; you can't be sure which line you just connected to and therefore which password to enter!

These passwords will all appear in your configuration file in plain text; anyone with access to that file could read them. To encrypt your Privileged EXEC password with an MD5 hash, use the enable secret command:

Router(config)#enable secret squirrel42

You can also apply encryption to the other passwords for the console, Privileged Exec VTY and TTY lines (but not the enable secret password [this Privileged EXEC password is already encrypted]) using the service password-encryption command:

Router(config)#service password-encryption

Exam Alert

Know the password configuration commands cold.


Configuring SSH Access to Your Router

Telnet is a simple and effective way to remotely administer your router or switch, but it has one significant disadvantage: it is completely unencrypted, which means that everything you send across the network via Telnet could be read easily if intercepted. That's not a good thing.

Secure Shell, or SSH, is a good alternative. It is slightly more complicated (but not difficult) to set up and
provides a secured remote command-line interface using public key exchange and decent encryption. Cisco
recommends (and we do, too!) that SSH always be used instead of Telnet for security reasons. Your IOS version must include support for DES or 3DES crypto features, or this will not work.

The following are the basic steps to set up a router for SSH support:

1. Define a username and password. SSH can't use the line password we created for Telnet access, so we must create a username/password pair for SSH to use. You might choose to make more than one, for different admins.
Router(config)#username Admin007 password ExamCram2

2. Configure the router to use the username/password. (We could use AAA instead of the command shown, but that is quite a large topic that we don't need to get into here).
Router(config-line)#login local

3. Set the router's domain name. This does not necessarily have to be the actual domain name of the company, but it makes sense if it is the domain that the router actually operates in. If there is not a defined domain in use, make one up. I used ExamCramLab.local in this example.
Router(config)#ip domain-name ExamCramLab.local

4. Create the public key. Simply put, this command creates the public key that will be used to allow secure connections from users supplying the correct credentials. This is the command that will fail if your IOS doesn't support the right crypto features.
Router(config)#crypto key generate rsa

5. (Optional) Restrict VTY line connections to SSH only, instead of both Telnet and SSH. It makes sense to do
this, although it is not strictly required for SSH to work.

Router(config)#line vty 0 4
Router(config-line)#transport input ssh


There's one other catch to using SSH instead of Telnet: You must have an SSH client application. Windows XP and Vista include a command-line SSH capability; I prefer to use terminal applications such as SecureCRT because they are feature rich and easier to use, in my opinion.
To connect to your router using SSH, launch your SSH client of choice, give it the IP address of the device you want to SSH to, and when prompted, supply the username and password you configured.

Tip

If you have access to the Web, you can find tons of good references about SSH configuration on cisco.com. If you don't have access to the Web, you need to get it!

Exam Alert

SSH is an important component of network security. You may be asked to identify why SSH is preferred over Telnet and what the required steps are to configure it. Although we have not seen it yet, we think it would be a great simulator question topic. You should know how to configure it.

- Command Shortcuts

Command Shortcuts

Take a look at this command. It backs up the current configuration and saves it so that the router will use it next time it boots up:

Router#copy running-config startup-config

That's a big hunk of typing. More typing means more time and more errors, so to save time, we can use
truncation. As long as the truncation provides enough information for the IOS to figure out what command you are trying to enter, you can reduce the amount of typing you have to do, saving yourself time:

Router#copy run start

Or even smaller

Router#cop ru st

That's a big savings in typing effort.

As you get used to working with the IOS, you will develop your own shortcuts.

The IOS will tell you when you make a mistake, too. There are three error messages:

Incomplete Command— The IOS needs more command keywords to complete the command. It advises you of the error, and retypes what you entered so that you can complete it. The error looks like this:

Router#copy running-config
% Incomplete Command
Router#copy running-config

Ambiguous Command— The IOS is not sure what command you mean because you truncated too much:

Router#co ru st
%Ambiguous command

Invalid Input— You made a typo or entered a command at the wrong prompt. Notice that the IOS will also show you exactly where the problem happens with a little pointer:

Router#cpy run start
^
%Invalid input detected at '^' marker


Context-Sensitive Help

The IOS has a complete listing of all the commands available. If you get stuck, you can use the question mark ? to access this help. You can use it in different ways:

On its own, to see a list of all the available command words at a particular prompt

Code View:

Router(config-if)#?
-Interface configuration commands:
-access-expression Build a bridge boolean access expression
-arp Set arp type (arpa, probe, snap) or timeout
-backup Modify dial-backup parameters
-bandwidth Set bandwidth informational parameter
-bridge-group Transparent bridging interface parameters
-carrier-delay Specify delay for interface transitions
-cdp CDP interface subcommands
-cmns OSI CMNS
-custom-queue-list Assign a custom queue list to an interface
-default Set a command to its defaults
-delay Specify interface throughput delay
-description Interface specific description
-exit Exit from interface configuration mode
-fair-queue Enable Fair Queuing on an Interface
-help Description of the interactive help system
-hold-queue Set hold queue depth
-ip Interface Internet Protocol config commands
-ipx Novell/IPX interface subcommands
-keepalive Enable keepalive
-llc2 LLC2 Interface Subcommands
-load-interval Specify interval for load calculation for an interface
—More—


After a command word, to see the next possible command words

Router# copy ?
running-config startup-config tftp:
flash:


Don't be afraid to use the help, especially when you are learning. The help commands also function (with limited capabilities) in the router simulator questions on the CCNA exam.

Basic Switch Configuration

A Cisco switch will function perfectly well right out of the box with no configuration required; however, it's a good idea to do a few basic configurations to personalize, secure, and optimize the device.

Setting the Hostname

The default hostname is "Switch," which not only lacks imagination, but also is confusing if you have a lot of them. Changing the hostname is simple:
Switch(config)#hostname My2960 My2960(config)#


Notice that the hostname instantly changed!

Setting a Management IP Address

If you want to Telnet to your switch to manage it remotely, have it participate in an SNMP system, or use the
integrated HTTP server for monitoring, your switch needs an IP address and gateway address. This IP address is applied to the VLAN1 interface and the default gateway is a global command on a switch—unlike a router, a switch has no physical ports that can be assigned IP addresses, so the virtual interface of VLAN1 (the management VLAN) gets the addresses:

My2960(config)#interface vlan1
My2960(config-if)#ip address 192.168.1.2 255.255.255.0 My2960(config-if)#exit
My2960(config)#ip default-gateway 192.168.1.1



Note

A default gateway is an IP address of a router that can connect you to another network. A switch needs a default gateway if it is going to communicate with any device on any IP network other than the one its VLAN1 IP address is in. This is most commonly needed for remote management of the switch using Telnet or SSH, for the switch to participate in SNMP, or any other IP operation that crosses to another network or subnet.



Setting Speed and Duplex on Ethernet Ports

Although the Ethernet interfaces will auto-detect the duplex and speed setting on a 2960, it is usually a good
idea to hard-code them when you are sure of what you are connecting to (such as a server, a switch, or router):

My2960(config)#interface f0/24
My2960(config-if)#speed 100
My2960(config-if)#duplex full

Basic Router Configuration

Routers need a little more configuration than switches to function properly; every interface that you want to use needs an IP address and mask, as well as to be enabled. You will probably need to add static routes or perhaps run a dynamic routing protocol. You need to configure your serial port for connectivity as well.

Serial Port Configuration

As we mentioned before, a Cisco serial port can run several different Layer2 encapsulations—meaning, it can




connect to different types of networks. You must be sure that the encapsulation type matches that of the device you are connecting to. In CCNA, we are interested only in three serial encapsulations: HDLC, PPP, and Frame Relay. The command to change the encapsulation is executed at the interface configuration prompt:

Router(config)#interface serial 0
Router(config-if)#encapsulation [hdlc frame-relay ppp]


You might also need to set up the serial speed by configuring a clock rate. Usually this is supplied by the service provider's device (the DCE—Data Communication Equipment), but in training labs we will hook a router directly to another router with a special back-to-back cable. In this situation, one of the devices must emulate the DCE, and the DCE sets the clock. Only one device needs the clock rate set.

You can also configure a bandwidth statement on the interface. This one is a little tricky; it looks like we are
setting the bandwidth (as in bits per second) of the interface, but we really aren't—the clock rate sets the
physical data rate. What we are doing with the bandwidth command is reporting to the routing protocols about the capacity of the interface (more on this in Chapter 9). It might have an actual clock rate of 64000 (64K), but we could lie and set the bandwidth to 56K for the purposes of routing information:

Router(config-if)#clock rate 64000
Router(config-if)#bandwidth 56



Note

Be aware of the syntax for clock rate and bandwidth: Clock rate is in bps, and bandwidth is in kbps. I remember it this way: clock rate is a longer command and needs a longer number (64000), and bandwidth, truncated as band so it's short, needs a shorter number (64).



Enabling Interfaces

By default, every interface on a router (whether it is brand new or has had its configuration erased) is in a
shutdown state. This is also known as administratively down; although the interface might have been perfectly configured with an IP and mask, encapsulation, and whatever else is needed, the interface is effectively off—even Layer 1 is down. A shutdown interface doesn't send or receive any data at all, and it causes the other end of a serial link to think it is dead altogether. So when you first configure a new router or one that has had its configuration erased, remember to issue the no shutdown command at each interface, or none of the interfaces will work!

Router(config-if)#no shutdown



Exam Alert

Understand that all interfaces are shut down by default until the 'no shut' command is issued.




On a router, every interface is a gateway to another network. For this reason, we do not need to supply a
default gateway. However, every interface you intend to use will need an IP address and mask. The commands

to set an IP are exactly the same as on a switch. Don't forget the no shutdown (no shut for short):

Router(config)#interface s0
Router(config-if)#ip address 10.0.0.1 255.0.0.0 Router(config-if)#no shut
Router(config-if)#interface e0
Router(config-if)#ip address 172.16.0.1 255.255.0.0 Router(config-if)#no shut

- Command Line Modes

Command Line Modes

Access to a router or switch command line is referred to as an EXEC session. There are two levels of access: user EXEC and privileged EXEC. In user exec mode, you have limited access to information and diagnostic commands, and you are not able to make configuration changes to the router. Privileged EXEC mode gives you the complete command set and full authority to change or erase the configuration.

When you connect to a router using the console port, you see a message like this:

Router Con0 is now available.
Press RETURN to get started!

Pressing Return takes you to the User Exec Prompt, which looks like this:

Router>

To go to Privileged EXEC mode, you must enter the command enable. The prompt will change from > to #, as shown:

Router>enable Router#

From this point, you can enter commands to view the status and settings of the router, make some kinds of changes, and erase, back up, or restore the IOS and configuration files.
To make most kinds of changes, however, you must enter the Global Configuration mode. This is done by entering the command configure terminal from the Privileged EXEC mode:

Router#configure terminal
Router(config)#


Notice that the command prompt changes to Router(config)#. From this prompt, you can make changes to functions that affect the whole router, or you can enter a more specific configuration mode to work with specialized functions. Some of the possible modes are listed and explained in the following:

Router(config)#interface serial 0
Router(config-if)#


This is the Interface configuration mode. Here you can set IP addresses and subnet masks, change speed, duplex, clock rate and bandwidth, or change the Layer 2 encapsulation of the interface. Changes made here affect only the interface you specified in the interface command.

Router(config)#line console 0
Router(config-line)#


Line Configuration mode allows you to set up line parameters. Lines include the console, AUX, TTY, and VTY connections. The console and aux lines are the local administration connections. TTY lines are synchronous serial connections, usually for analog dialup access with modems. The VTY lines are virtual connections for Telnet access to the router to perform remote administration over an IP network.

Router(config)#router rip
Router(config-router)#

Chapter 4. Working with Cisco Equipment

Chapter 4. Working with Cisco Equipment

Products

The CCNA exam does not test you about product-specific knowledge. That is to say, you are not expected to know what feature cards are available for a 6500 series switch, but you do need to understand the differences between a router and a switch, and you need to understand how their configuration requirements vary. For our purposes, we use a Catalyst 2960 or 3560 switch and a 1600, 1700, or 2600 series router as example devices. Most of the commands you learn in this chapter also apply to more advanced models.





External Connections

Cisco devices make connections to other devices, and collectively they all create a network. At some point, making a connection means plugging in a cable—even with a wireless system. This section examines some of the various connections found on Cisco routers and switches.

Console

When you first obtain a new Cisco device, it won't be configured. That is to say, it will not do any of the
customized functions you might need; it does not have any IP addresses, and it is generally not going to do what you paid for. However, if you buy a 2960 switch, turn on the power, and plug PCs in to it, it will work to connect those PCs with no further configuration, but you are missing out on all the cool stuff and advanced features. Your new router, on the other hand, will not be capable of doing much for you at all, even if you plug devices into the interfaces. Routers need basic configuration to function on a network, or they simply consume power and blink at you.

The console port is used for local management connections. This means that you must be able to physically reach the console port with a cable that is typically about six feet long. The console port looks exactly like an Ethernet port. It uses the same connector, but it has different wiring and is often (but not always) identified with a pale blue label that says "CONSOLE." If the device is not configured at all—meaning, if it is new or has had a previous configuration erased—the console port is the only way to connect to it and apply configurations.



Serial Port

A Cisco serial port is a proprietary design, a 60-pin D-sub. This connector can be configured for almost any kind of serial communication. You need a cable that has the Cisco connector on one end and the appropriate type of connector for the service you want to connect to on the other.

Serial ports are almost always used for WAN connections and use one of several Layer 2 protocols including Frame Relay, PPP, and HDLC. Serial ports can also connect to an ISDN Primary Rate Interface (PRI) service or regular analog telephone service. (For a telephone service, you need a special hardware type called an asynchronous serial port and a modem.)

HDLC is the default encapsulation on a Cisco serial port, and the HDLC protocol here is a Cisco proprietary version of the standardized ISO HDLC that can run multiple Layer 3 protocols, which the ISO version can't do.
You might have one or more serial ports depending on what you need and what you buy.


Exam Alert

You will need to know the three WAN encapsulations for a serial port: HDLC, PPP, and Frame Relay. These will be discussed in more detail later.

Know that Cisco's HDLC is the default encapsulation for serial ports.

Other Connections

Your router may use a T1 controller card to connect to a T1 WAN service. The controller will probably have a label that reads "T1 CSU/DSU," with a plug that looks like the RJ-45 connector but is actually an RJ-48. You can also buy ports for High-Speed Serial communication (perhaps ATM) or even different fiber-optic connections. What you purchase will depend on the services you need to connect to, the model of router you buy, and of course how much money you want to spend. Although the "Other Connections" listed here are by no means an exhaustive list of your options, they are the most commonly used. These connection types are not tested, but are included here for your interest.

Reference : CCNA Exam Cram (Exam 640-802), Third Edition by Michael Valentine; Andrew Whitaker

Chapter 3. Concepts in ip addressing

IP Address Components

CCNA candidates need to be fluent in their understanding of IP addressing concepts. The following sections detail how IP addresses are organized and analyzed, with a view to answering subnetting questions.

Address Class

Early in the development of IP, the IANA (Internet Assigned Numbers Authority) designated five classes of IP
address: A, B, C, D, and E. These classes were identified based on the pattern of high-order bits (the high-value bits at the beginning of the first octet). The result is that certain ranges of networks are grouped into classes in a pattern based on the binary values of those high-order bits


Address Class and Range

Class High-Order Bits 1st Octet Range
A 0 1-126
B 10 128-191
C 110 192-223
D 1110 224-239
E 11110 240-255


You might notice that 127 is missing. This is because at some point the address 127.0.0.1 was reserved for the loopback (sometimes called "localhost") IP—this is the IP of the TCP/IP protocol itself on every host machine.

Exam Alert

You absolutely must be able to identify the class of an address just by looking at what number is in the first octet. This is critical to answering subnetting questions.



Default Subnet Mask

Each class of address is associated with a default subnet mask, defines a single IP broadcast domain—all the hosts using that same network number and mask can receive each other's broadcasts and communicate via IP.


Address Class and Default Masks
Class Default Mask
A 255.0.0.0
B 255.255.0.0
C 255.255.255.0


One of the rules that Cisco devices follow is that a subnet mask must be a contiguous string of 1s followed by a contiguous string of 0s. There are no exceptions to this rule: A valid mask is always a string of 1s, followed by 0s to fill up the rest of the 32 bits. (There is no such rule in the real world, but we will stick to the Cisco rules here—it's a Cisco exam, after all.)

Therefore, the only possible valid values in any given octet of a subnet mask are 0, 128, 192, 224, 240, 248, 252, 254, and 255. Any other value is invalid.


Exam Alert

You should practice associating the correct default subnet mask with any given IP address; this is another critical skill in subnetting.



Exam Questions


1. Which of the following are alternate representations of the decimal number 227? Choose 2.

A. 0x227
B. 11100011
C. 0x143
D. 0xE3
E. 11100110

Answers B and D are correct. Answer A in decimal would be 551. Answer C in decimal would be
323. Answer E in decimal is 230.

2. Which of the following are alternate representations of 0xB8? Choose two.

A. 10110100
B. 10111111
C. 10111000
D. 184
E. 0x184

Answers C and D are correct. Answer A in hex is 0xB4. Answer B in hex is 0xBF. Answer E is simply
an attempt to trick you—the correct decimal answer is incorrectly expressed as a hex value.

3. You have been asked to create a subnet that supports 16 hosts. What subnet mask should you
use?

A. 255.255.255.252
B. 255.255.255.248
C. 255.255.255.240
D. 255.255.255.224

Answer D is correct. A will only support 2 hosts; B only 6, and C only 14. Watch out for the minus
2 in the host calculation! Answer C creates 16 hosts on the subnet, but we lose 2—one for the Net ID and one for the Broadcast ID.

4. Given the mask 255.255.254.0, how many hosts per subnet does this create?

A. 254
B. 256
C. 512
D. 510
E. 2

Answer D is correct. The mask 255.255.254.0 gives us nine 0s at the end of the mask; 29-2 =
510. Answer A is checking to see if you missed the 254 in the third octet because you are used to seeing 255. Answer B does the same thing plus tries to catch you on not subtracting 2 from the host calculation. Answer C tries to catch you on not subtracting 2, and Answer E is the Increment of the given mask that you might pick if you were really off track.

5. You are a senior network engineer at True North Technologies. Your boss, Mr. Martin, asks you to create a subnet with room for 12 IPs for some new managers. Mr. Martin promises that there will never be more than 12 managers, and he asks you to make sure that you conserve IP address space by providing the minimum number of possible host IPs on the subnet. What subnet mask will best meet these requirements?

A. 255.255.255.12
B. 255.255.255.0
C. 255.255.240.0
D. 255.255.255.240
E. 255.255.255.224

Answer The correct answer is D. Disregarding for the moment the possibility that Mr. Martin might be wrong, let's look at the requirements. He says make room for 12 managers, and make the subnets as small as possible while doing so. You need to find the mask that has sufficient host IP space without making it bigger than necessary. Answer A is invalid; 12 is not a valid mask value. Remember, a mask is a continuous string of 1s followed by a continuous string of 0s. In answer B, the mask is valid, but it is not correct. This mask has eight 0s at the end, which, when we apply the formula 28 -2 gives us 254 hosts. That makes more than enough room for the 12 managers, but does not meet the "as small as possible" requirement. Answer C has the correct mask value in the wrong octet. That mask gives us eight 0s in the fourth octet, plus another four in the third octet; that would give us 4094 hosts on the subnet. Answer E gives us 30 hosts per subnet, but that only meets half the requirement. This mask does not provide the minimum number of hosts

6. Your boss Duncan does not seem to be able to grasp subnetting. He comes out of a management meeting and quietly asks you to help him with a subnetting issue. He needs to divide the Class B address space the company uses into six subnets for the various buildings in the plant, while keeping the subnets as large as possible to allow for future growth. Because the company has not upgraded their Cisco equipment since it was purchased several years ago, none of the routers supports the "ip subnet zero" command. What is the best subnet mask to use in this scenario?

A. 255.255.0.0
B. 255.255.248.0
C. 255.255.224.0
D. 255.255.240.0
E. 255.255.255.224

The correct answer is C. The default mask for a Class B is 255.255.0.0. Answer C extends that
mask by three bits, creating eight subnets (23=8). The Zero Subnets are lost because the routers cannot use them, so we are left with six subnets. Answers A is incorrect because it is the default mask for a Class B and not subnetted at all. Answer B and D are incorrect because although they create sufficient subnets, they do not maximize the number of hosts per subnet and so are not the best answer. Answer E uses the correct mask in the wrong octet.

7. You have purchased several brand-new Cisco routers for your company. Your current address
space is 172.16.0.0 /22. Because these new routers support the "ip subnet zero" command, you realize you are about to gain back two subnets that you could not use with the old gear. How many subnets total will be available to you once the upgrades are complete?

A. 4
B. 2
C. 32
D. 62
E. 64

Answer E is correct. With "ip subnet zero" enabled, all 64 subnets created by the mask in use
become available. Answers A, B, and C are not even close and are simply distracters. Answer D wants to catch you by subtracting the zero subnets.

8. Which of the following are true about the following address and mask pair: 10.8.8.0 /24? Choose all that apply.

A. This is a Class B address.
B. This is a Class A address.
C. This is a Class C address.
D. 16 bits were stolen from the host field.
E. 24 bits were stolen from the host field.
F. The default mask for this address is 255.0.0.0.
G. The mask can also be written as 255.255.255.0.
H. The mask creates 65,536 subnets total from the default address space.
I. Each subnet supports 256 valid host IPs.
J. Each subnet supports 254 valid host IPs.

The correct answers are B, D, F, G, H, and J. Answers A and C are incorrect because this is a Class
A address. Answer E is incorrect because only 16 bits were stolen. Answer I is incorrect because it does not subtract the two IPs for the NetID and Broadcast ID.


9. Indy and Greg have configured their own Windows XP PCs and connected them with crossover
cables. They can't seem to share their downloaded MP3 files, however. Given their configurations, what could be the problem?

Indy's configuration:
IP: 192.168.0.65
Mask: 255.255.255.192

Greg's configuration:

IP: 192.168.0.62
Mask: 255.255.255.192


A. Indy is using a Broadcast ID for his IP.
B. Greg is using an invalid mask.
C. Indy's IP is in one of the Zero Subnets.
D. Greg and Indy are using IPs in different subnets.

Answer D is correct. With that mask, the Increment is 64. Greg is in the first subnet, and Indy is in
the second. Without a router between them, their PCs will not be able to communicate above layer
2. Answer A is incorrect; the Broadcast ID for Indy would be .63. Answer B is incorrect; nothing is wrong with the mask. Answer C is incorrect; the Zero Subnets are the first and last created, and Indy is in the second subnet. The question does not mention the Zero Subnets, and in any case Windows XP fully supports them.


10. You are given an old router to practice for your CCNA. Your boss Dave has spent a lot of time
teaching you subnetting. Now he challenges you to apply your knowledge. He hands you a note that says:
"Given the subnetted address space of 192.168.1.0 /29, give the E0 interface the first valid IP in the eighth subnet. Give the S0 interface the last valid IP in the twelfth subnet. The Zero Subnets are available. You have 10 minutes. Go."

Which two of the following are the correct IP and Mask configurations? Choose 2.
255.255.255.0

A. E0: 192.168.1.1
255.255.255.248

B. E0:
192.168.1.56
255.255.255.248

C. E0:
192.168.1.57
255.255.255.0

D. S0:
192.168.1.254
255.255.255.248

E. S0:
192.168.1.95
255.255.255.248


The correct answers are C and F. This is an Increment question. The Increment here is 8, so you
should start by jotting down the multiples of 8 (those are all the NetIDs), and then noting what 1 less than each of the NetIDs is (those are the Broadcast IDs). From there, it is easy to find what the first and last IPs in each subnet are. (Remember that Dave says we can use the Zero Subnets.) Answers A and D are incorrect because they do not use the subnetted address space Dave requested. Answer B is incorrect because it is a NetID. Answer E is incorrect because it is a Broadcast ID.

Chapter 2. Protocols TCP/IP

Chapter 2. Protocols TCP/IP


TCP/IP Model

Although the TCP/IP protocol can be fit into the OSI model, it actually uses its own model,
which is slightly different. Remember that the OSI model is intended to be a standardized framework, and TCP/IP was originated as a proprietary Department of Defense protocol. It stands to reason that there will be some variances from the official OSI stack. The following section describes these differences.

The TCP/IP model has only four layers:

• Application
• Transport
• Internet
• Network interface
  
  
  OSI Layers 5, 6, and 7 have been amalgamated into a single layer called the application layer. The Application layer features all the same protocols as found in OSI Layer 7: Telnet, FTP, TFTP, SMTP, SNMP, and so on. The transport layer is equivalent to OSI Layer 4. TCP and UDP are located here.
  
  The Internet layer corresponds to OSI Layer 3. IP, ARP, and ICMP are the primary protocols here.
  
  Layer 1 and 2 are fused into the network interface layer. This is confusing because it is illogical to have a protocol software stack define a physical interface; just remember that the TCP/IP model is a logical framework, and the fact that physical standards are included is necessary because it must connect to the media at some point. The TCP/IP model uses the same definitions for Network Interface standards as the OSI model does for data link and physical layers.

*****************************************

Exam Questions

*****************************************

1. Which protocols use TCP? Choose all that apply.

A. DNS

B. SNMP

C. SMTP

D. FTP

E. TFTP

F. POP3

Answers A, C, D, and F are correct. DNS uses both TCP and UDP; B and E use UDP only.

---------------------------------------------------

2. Which layer of the TCP/IP model is responsible for interhost data movement, using either connection-oriented or connectionless protocols?

A. Network

B. Internet

C. Transport

D. Network interface

Answer C is correct; connectionless and connection-oriented protocols are found at Layer 4 (transport). Answer A is incorrect because it is an OSI layer name; Answers B, D, and E are incorrect because those layers do not use connection-oriented or connectionless protocols.

-------------------------------------------------

Chapter 1. Network Models

Chapter 1. Network Models

• OSI Model : Open Systems Interconnection (OSI)

The International Standards Organization (ISO) defined a seven-layer model to standardize networking processes

The seven layers, in order, are as follows:

7. Application

6. Presentation

5. Session

4. Transport

3. Network

2. Data link

1. Physical


Exam Questions


1. Which protocol will allow you to test connectivity through Layer 7?

A. ICMP
B. ARP
C. RIP
D. Telnet

Answer D is the correct answer; Telnet is the only Layer 7 protocol listed. All the others only
operate at Layer 3, so they do not test above Layer 3.

-------------------------------------------------------------------------------------------------

2. Which answer correctly lists the OSI PDUs in order?

A. Data, Packet, Frame, Segment, Bit
B. Bit, Data, Packet, Segment, Frame
C. Data, Segment, Packet, Frame, Bit
D. Bit, Frame, Segment, Packet, Data

Answer C is the correct answer. "Did Sally Pack for Bermuda?"

-------------------------------------------------------------------------------------------------

3. Which transport layer protocol provides connection-oriented, reliable transport?

A. TFTP
B. UDP
C. Ethernet
D. TCP
E. Secure Shell

Answer D is the correct answer. TCP is a transport-layer protocol that uses sequencing,
acknowledgments, and retransmission for reliability. Answers A, C, and E are incorrect because
TFTP, Ethernet, and Secure Shell are not transport-layer protocols; Answer B is incorrect because
UDP does not provide reliability.

-------------------------------------------------------------------------------------------------

4. Which of the following are application layer protocols? Choose all that apply.

A. Ethernet
B. CDP
C. FTP
D. TFTP
E. Telnet
F. ARP
G. ICMP
H. ATM

Answers C, D, and E are correct. Answers A, B, and H are Layer 2 protocols; Answers F and G are
Layer 3 protocols.

-------------------------------------------------------------------------------------------------

5. Match the protocol with its port number:

FTP 80
Telnet 69
TFTP 20,21
DNS 123
SNMP 25
SMTP 110
NTP 161
POP3 53
HTTP 23

Answer:

FTP 20, 21
Telnet 23
TFTP 69
DNS 53
SNMP 161
SMTP 25
NTP 123
POP3 110
HTTP 80

-------------------------------------------------------------------------------------------------

5 STEP : To CCNA

CCNA Certification ปัจจุบัน การสอบเพื่อให้ได้มาซึ่ง CCNA นั้น แทบจะถือได้ว่าเป็นสิ่งที่หลีกเลี่ยงไม่ได้สำหรับใครก็ตามที่สนใจจะทำงานด้านเน็ตเวิร์ก เพราะอย่างน้อยๆ มันก็ช่วยยืนยันความรู้เกี่ยวกับเน็ตเวิร์กและ อุปกรณ์ซิสโก้ที่ใช้งานในเน็ตเวิร์กส่วนใหญ่ขององค์กร และผู้สอบผ่านพอจะมีความรู้พื้นฐานพอควรใน การก้าวสู่ประกาศนียบัตรในระดับสูงต่อไป

ใครๆก็สามารถสอบได้ หากมีใจรักด้าน Network และอยากทำงานด้านนี้

การสมัครสอบ Cisco Career Certification

ตัวอย่างการทำข้อสอบ

ข้อสอบจะมีประมาณ 55-65 ข้อซ้อมทำข้อสอบก่อนลงสนามจริง ออกตามนี้นะ
• STEP 1 : INTRODUCTION

Chapter 1. Network Models

Chapter 2. Protocols TCP/IP

Chapter 3. Concepts in ip addressing

• STEP 2 : ROUTING

Chapter 4. Working with Cisco Equipment

Chapter 5. Managing Your Router

Chapter 6. Basic Routing and Static Route

Chapter 7. Distance Vector (RIP/IGRP)

Chapter 8. Link State (OSPF)

Chapter 9. Hybrid (EIGRP)

Chapter 10. Variable Length Subnet Mask (VLSM), Classless InterDomain Routing (CIDR) and Basic Route Summarization

• STEP 3 : SWITCHING
• STEP 4 : WIDE AREA NETWORK
  
• STEP 5 : ADVANCED FEATURES AND SECURITY