CCNA 1 Final Exam V4.0 Answers

1.Refer to the exhibit. What is the correct destination socket number for a web page request from Host A to the web server?
00-08-a3-b6-ce-46
198.133.219.25:80

http://www.ccnafinal.net

C 198.133.219.0/24 is directly connected, FastEthernet0/0

2. Which prompt represents the appropriate mode used for the copy running-config startup-config command ?
Switch-6J>
Switch-6J#
Switch-6J(config)#
Switch-6J(config-if)#
Switch-6J(config-line)#

3. Due to a security violation, the router passwords must be changed. What information can be learned from the following configuration entries? (Choose two)
Router(config)# line vty 0 3 Router(config-line)# password c13c0
Router(config-line)# login
The entries specify three Telnet lines for remote access.
The entries specify four Telnet lines for remote access.
The entries set the console and Telnet password to “c13c0″.
Telnet access will be denied because the Telnet configuration is incomplete.
Access will be permitted for Telnet using “c13c0″ as the password.

4.

Refer to the exhibit. Each media link is labeled. What type of cable should be used to connect the different devices?
Connection 1 – rollover cable
Connection 2 – straight-through cable
Connection 3 – crossover cable
Connection 1 – crossover cable
Connection 2 – rollover cable
Connection 3 – crossover cable
Connection 1 – straight-through cable
Connection 2 – crossover cable
Connection 3 – crossover cable
Connection 1 – straight-through cable
Connection 2 – crossover cable
Connection 3 – straight-through cable
Connection 1 – crossover cable
Connection 2 – straight-through cable
Connection 3 – crossover cable

5.

Refer to the exhibit. What function does router RT_A need to provide to allow Internet access for hosts in this network?
address translation
DHCP services
ftpd
web server

6. When connectionless protocols are implemented at the lower layers of the OSI model, what is usually used to acknowledge that the data was received and to request the retransmission of missing data?
IP
UDP
Ethernet
a connectionless acknowledgement
an upper-layer, connection-oriented protocol or service

7.

Refer to the exhibit. Host A is transmitting data to host B. What addresses will host A use to for the destination IP and MAC addresses in this communication?
Destination MAC: BBBB:BBBB:BBBB Destination IP: 172.22.0.62
Destination MAC: DDDD:DDDD:DDDD Destination IP: 172.22.0.75
Destination MAC: EEEE:EEEE:EEEE Destination IP: 172.22.0.62
Destination MAC: BBBB:BBBB:BBBB Destination IP: 172.22.0.75
Destination MAC: EEEE:EEEE:EEEE Destination IP: 172.22.0.75
Destination MAC: DDDD:DDDD:DDDD Destination IP: 172.22.0.94

8.

Refer to the exhibit. Cable 1 and cable 2 have the ends wired for specific physical layer requirements. The table lists each segment by number and the cable which has been installed by the network technician between the network components on that segment. From the data given, which segments have the correct cable installed? (Choose three.)
segment1
segment2
segment3
segment4
segment5

9. What is true regarding network layer addressing? (Choose three)
uses a flat structure
prevent broadcasts
heirarchical
uniquely identifies each host
48 bits in length
contains a network portion

10.

Refer to the exhibit. What two facts can be determined about the exhibited topology? (Choose two)
A single broadcast domain is present
Two logical address ranges are required.
Three broadcast domains are shown.
Four networks are needed.
Five collision domains exist.

11.

Refer to the exhibit. What two facts can be determined from the information that is given? (Choose two.)
This exchange is part of the three-way handshake.
The source port indicates that a Telnet session has been initiated.
The data is flowing from server to client.
The destination port indicates that an HTTP session has been initiated.
The data listed is associated with the transport layer.
The source port does not support communication with the destination port that is listed.

12. In a Cisco IOS device, where is the startup-configuration file stored?
Flash
NVRAM
RAM
ROM

13.

Refer to the exhibit. The network containing router B is experiencing problems. A network associate has isolated the issue in this network to router B. What action can be preformed to correct the network issue?
issue the clock rate command on interface Serial 0/0/0
issue the description command on interface Serial 0/0/1
issue the ip address command on interface FastEthernet 0/0
issue the no shutdown command on interface FastEthernet 0/1

14.

Refer to the exhibit. A technician is working on a network problem that requires verification of the router LAN interface. What address should be pinged from this host to confirm that the router interface is operational?
127.0.0.1
192.168.64.196
192.168.254.1
192.168.254.9
192.168.254.254

15. Which combination of network id and subnet mask correctly identifies all IP addresses from 172.16.128.0 through 172.16.159.255?
172.16.128.0 255.255.255.224
172.16.128.0 255.255.0.0
172.16.128.0 255.255.192.0
172.16.128.0 255.255.224.0
172.16.128.0 255.255.255.192

16.

Refer to the exhibit. Host A attempts to establish a TCP/IP session with host C. During this attempt, a frame was captured with the source MAC address 0050.7320.D632 and the destination MAC address 0030.8517.44C4. The packet inside the captured frame has an IP source address 192.168.7.5, and the destination IP address is 192.168.219.24. At which point in the network was this packet captured?
leaving host A
leaving ATL
leaving Dallas
leaving NYC

17.

Refer to the exhibit. The diagram represents the process of sending email between clients. Select the list below that correctly identifies the component or protocol used at each numbered stage of the diagram.
1.MUA 2.MDA 3.MTA 4.SMTP 5.MTA 6.POP 7.MDA 8.MUA
1.MUA 2.POP 3.MDA 4.SMTP 5.MTA 6.MDA 7.SMTP 8.MUA
1.MUA 2.POP 3.SMTP 4.MDA 5.MTA 6.SMTP 7.POP 8.MUA
1.MDA 2.SMTP 3.MTA 4.SMTP 5.MTA 6.MUA 7.POP 8.MDA
1.MUA 2.SMTP 3.MTA 4.SMTP 5.MTA 6.MDA 7.POP 8.MUA

18.

Refer to the exhibit. The command that is shown was issued on a PC. What does the IP address 192.168.33.2 represent?
IP address of the host
default gateway of the host
IP address of the homepage for the host
primary domain name server for the host
IP address of the website resolver1.mooki.local

19.

Refer to the exhibit. On the basis of the IP configuration that is shown, what is the reason that Host A and Host B are unable to communicate outside the local network?
Host A was assigned a network address.
Host B was assigned a multicast address.
Host A and Host B belong to different networks.
The gateway address was assigned a broadcast address.

20.

Refer to the exhibit. The tracert command is initiated from PC1 to PC4. Which device will send a response to the initial tracert packet from PC1?
Athens
Ankara
London
Paris
PC4

21. Which password is automatically encrypted when it is created?
vty
aux
console
enable secret
enable password

22. Which OSI layer does IP rely on to determine whether packets have been lost and to request retransmission?
application
presentation
session
transport

23.

Refer to the exhibit. Which two statements describe the information that is represented in the header? (Choose two)
This is a server response.
The UDP protocol is being used.
The destination port indicates a Telnet session.
The return segment will contain a source port of 23.
The next session originated from the client of this session will use the source port number 13358.

24. The Layer 4 header contains which type of information to aid in the delivery of data?
service port number
host logical address
device physical address
virtual connection identifier

25. As network administrator, what is the subnet mask that allows 510 hosts given the IP address 172.30.0.0?
255.255.0.0
255.255.248.0
255.255.252.0
255.255.254.0
255.255.255.0
255.255.255.128

26. When must a router serial interface be configured with the clock rate command?
when the interface is functioning as a DTE device
when the interface timers have been cleared
when the connected DTE device is shut down
when the interface is functioning as a DCE device

27.

Refer to the exhibit. What is required on host A for a network technician to create the initial configuration on Router1?
an FTP client
a Telnet client
a terminal emulation program
a web browser

28.

Refer to the exhibit. Which set of devices contains only intermediary devices?
A, B, D, G
A, B, E, F
C, D, G, I
G, H, I, J

29.

Refer to the exhibit. A network technician is trying to determine the correct IP address configuration for Host A. What is a valid configuration for Host A?
IP address: 192.168.100.19; Subnet Mask: 255.255.255.248; Default Gateway: 192.16.1.2
IP address: 192.168.100.20; Subnet Mask: 255.255.255.240; Default Gateway: 192.168.100.17
IP address: 192.168.100.21; Subnet Mask: 255.255.255.248; Default Gateway: 192.168.100.18
IP address: 192.168.100.22; Subnet Mask: 255.255.255.240; Default Gateway: 10.1.1.5
IP address: 192.168.100.30; Subnet Mask: 255.255.255.240; Default Gateway: 192.168.1.1
IP address: 192.168.100.31; Subnet Mask: 255.255.255.240; Default Gateway: 192.168.100.18

30. A routing issue has occurred in you internetwork. Which of the following type of devices should be examined to isolate this error?
access point
host
hub
router
switch

31. Which type of media is immune to EMI and RFI? (Choose two.)
10 Base-T
10 Base-2
10 Base-5
100 Base-FX
100 Base TX
1000 Base LX

32.

Refer to the exhibit. With the router running NAT, what IP addresses can be applied to the computer to allow access to the Internet? (Choose three)
192.168.18.38
192.168.18.48
192.168.18.49
192.168.18.52
192.168.18.59
192.168.18.63

33. Which three IPv4 addresses represent a broadcast for a subnet? (Choose three.)
172.16.4.63 /26
172.16.4.129 /26
172.16.4.191 /26
172.16.4.51 /27
172.16.4.95 /27
172.16.4.221 /27

34.

Refer to the exhibit. Assume all devices are using default configurations. How many subnets are required to address the topology that is shown?
1
3
4
5
7

35. What are three characteristics of CSMA/CD? (Choose three)
Devices can be configured with a higher transmission priority.
A jam signal indicates that the collision has cleared and the media is not busy.
A device listens and waits until the media is not busy before transmitting.
The device with the electronic token is the only one that can transmit after a collision.
All of the devices on a segment see data that passes on the network medium.
After detecting a collision, hosts can attempt to resume transmission after a random time delay has expired.

36. A technician is asked to secure the privileged EXEC mode of a switch by requiring a password. Which type of password would require this login and be considered the most secure?
console
enable
enable secret
VTY

37. A PC can not connect to any remote websites, ping its default gateway, or ping a printer that is functioning properly on the local network segment. Which action will verify that the TCP/IP stack is functioning correctly on this PC?
Use the ipconfig /all command at the host’s command prompt.
Use the ping 127.0.0.1 command at the command prompt.
Use the traceroute command at the command prompt to identify any failures on the path to the gateway.
Use FTP to check for connectivity to remote sites.
Download a troubleshooting tool from the PC manufacturer’s website.

38.

Refer to the exhibit. When computer A sends a frame to computer D, what computers receive the frame?
only computer D
only computer A and computer D
only computer B, computer C, and computer D
all computers

39.

Examine the graphic with current configurations. Host A in the Clerical offices failed and was replaced. Although a ping to 127.0.0.1 was successful, the replacement computer can not access the company network. What is the likely cause of the problem?
IP address incorrectly entered
network cables unplugged
subnet mask incorrectly entered
network card failure

40. Which two functions of the OSI model occur at layer two? (Choose two.)
physical addressing
encoding
routing
cabling
media access control

41.

Refer to the exhibit. A router, whose table is shown, receives a packet that is destined for 192.168.1.4. How will router treat the packet?
The packet will be dropped.
The packet will be forwarded via FastEthernet 0/0.
The packet will be forwarded to the destination host.
The packet will be forwarded to the 192.168.1.3 next-hop address.

42. Which range of port numbers are reserved for services that are commonly used by applications that run on servers?
0 to 255
0 to 1023
1024 to 49151
49152 to 65535

43.

Refer to the exhibit. What three statements are true about the IP configuration that is shown? (Choose three.)
The address that is assigned to the computer represents private addressing.
The computer is unable to communicate outside of the local network.
The network of this computer can have 126 hosts.
The prefix of the computer address is /27.
The IP address that is assigned to the computer is routable on the Internet.
The IP address that is assigned to the computer is a broadcast address.

44.

Refer to the exhibit. A network administrator remotely accesses the CLI of RouterB from PC1 using Telnet. Which statement is true about this connection?
The data is automatically encrypted.
A Telnet server process is running on PC1.
The connection is made through a VTY session on the router.
A GET request was sent to RouterB to retrieve data during this session.

45. Which three statements characterize the transport layer protocols? (Choose three.)
TCP and UDP port numbers are used by application layer protocols.

TCP uses port numbers to provide reliable transportation of IP packets.
UDP uses windowing and acknowledgments for reliable transfer of data.
TCP uses windowing and sequencing to provide reliable transfer of data.
TCP is a connection-oriented protocol. UDP is a connectionless protocol.

46. Which of the following are the address ranges of the private IP addresses? (Choose three.)
10.0.0.0 to 10.255.255.255
200.100.50.0 to 200.100.25.255
150.150.0.0 to 150.150.255.255
172.16.0.0 to 172.31.255.255
192.168.0.0 to 192.168.255.255
127.16.0.0 to 127.31.255.255

47. Which OSI layers offers reliable, connection-oriented data communication services?
application
presentation
session
transport
network

48.

Refer to the exhibit. Which logical topology best describes the exhibited network?
star
ring
point-to-point
multiaccess
mesh

49. During the encapsulation process, which identifiers are added at the transport layer?
two networks routing the packets
two applications communicating the data
two hosts at either end of the communication
two nodes on the local network exchanging the frame

50. What are two characteristics of the data link layer? (Choose two.)
It segments and reorders the data.
It exchanges the frames between nodes.
It defines the method by which network devices place data onto the media.
It manages the transfer of data between the processes that run on each host.
It retrieves signals from the media and restores them to their bit representations.

Switch interfaces configuration

Lab instructions

This lab will test your ability to configure speed, duplex, and vlan settings on a cisco switchinterfaces.

1. Connect to Switch0 using console interface and configure each Switch0 fastethernet switchport for operation. Correct settings are :
- Port type : access port
- Speed : 100 Mbit/s
- Duplex mode : Full Duplex
- Autonegotiation disabled

2. PC “192.168.1.4″ seems to be unable to ping other PCs in the network. Check switch configuration.
TIP : How many broadcast domains are there in this network ?

3. Choose the right cable to connect :
- Switch0 gigabitethernet 1/1 to Switch1 gigabitethernet 1/1
- Switch1 gigabitethernet 1/2 to Switch2 gigabitethernet 1/2

4. Configure those two links as trunk lines without using trunk negotiation between switches

Network diagram

lab2-networkdiagram

Solution

Connect to Switch0 using console interface and configure each Switch0 fastethernet switchport for operation.

Switch(config)#interface FastEthernet0/1

switchport mode access
duplex full
speed 100

Switch(config)#interface FastEthernet0/2

switchport mode access
duplex full
speed 100

Switch(config)#interface FastEthernet0/3

switchport mode access
duplex full
speed 100

Switch(config)#interface FastEthernet0/4

switchport mode access
duplex full
speed 100

PC “192.168.1.4″ seems to be unable to ping other PCs in the network. Check switch configuration.
Switch(config)#interface FastEthernet0/4

Switch(config-if)#switchport mode access

Switch(config-if)#switchport access vlan 1
Choose the right cable to connect :
- Switch0 gigabitethernet 1/1 to Switch1 gigabitethernet 1/1
- Switch1 gigabitethernet 1/2 to Switch2 gigabitethernet 1/2

lab2-networkdiagram-solution

Configure those two links as trunk lines without using trunk negotiation between switches

On every interface that has to be configured for trunk operation, configure the following settings

Switch(config)#interface GigabitEthernet1/X

Switch(config-if)#switchport mode trunk

Verify interface operational mode using the “show interface GigabitEthernet1/X switchport command” :

Name: Gig1/2

Switchport: Enabled

Administrative Mode: trunk

Operational Mode: trunk

Administrative Trunking Encapsulation: dot1q

Operational Trunking Encapsulation: dot1q

Negotiation of Trunking: On

Access Mode VLAN: 1 (default)

Trunking Native Mode VLAN: 1 (default)

Voice VLAN: none

Another usefull ios command is “show interfaces trunk” :

Switch#sh interfaces trunk
Port Mode Encapsulation Status Native vlan
Gig1/2 on 802.1q trunking 1

Port Vlans allowed on trunk
Gig1/2 1-1005

Port Vlans allowed and active in management domain
Gig1/2 1

Port Vlans in spanning tree forwarding state and not pruned
Gig1/2 1

BCRAN - Building Cisco® Remote Access Networks exam

BCRAN - Building Cisco® Remote Access Networks exam is a requirement towards obtaining CCNP certification. Skills measured are: Building Cisco® Remote Access Networks exam include topics on Designing and implementing remote access networks using Dial-up, ISDN BRI, PRI; Authentication schemes, Frame Relay, X.25 network configurations. Valid CCNA certification is a pre-requisite for obtaining CCNP certification. The exam also counts toward CCDP Certification.

To be CCNP certified, the following exams need to be successfully completed:

Exam	Exam Code	Study material covering exam objectives
BSCI	642-801	Building Scalable Cisco Internetworks. Note that BSCI replaces Routing Exam (640-603).
Switching Exam	642-811	Building Cisco Multi-layer Switched Network or BCMSN
Remote Access Exam	642-821	Building Cisco Remote Access Networks
Support Exam	642-831	Cisco Internetwork Troubleshooting

Alternatively, one can take the following exams to obtain CCNP certification:

Exam	Exam Code	Study material covering exam objectives
Foundations Exam	642-891 Composite	Building Scalable Cisco Networks,
		Building Cisco Multi-layer Switched Network.
Remote Access	642-821	Building Cisco Remote Access Networks
Support Exam	642-831	Cisco Internetwork Troubleshooting.

Exam cram 0 1 2 3 4 5

1.0 Central site equipment:

Cisco^® recommends any of the following router equipment for central site or Corporate site:

1. Cisco 3600 series: Several models are available including 3620, 3640, and 3660. 36XX series of routers/access servers support variety of connections and protocols. The supported network interfaces include the following:
Ethernet, Fast Ethernet, Token Ring, Asynchronous, Synchronous serial, High Speed Serial Interface, ISDN BRI, Channelized T1/ISDN PRI (with and without CSU) , Digital Modems, Analog Modems, Voice, among others.

2. Cisco 4000 series: Cisco 4000 series include Cisco 4500 and Cisco 4700. Each of these have three network module slots. The presence of network module slots allows us to use variety of network modules and protocols. WAN Interface Card (WIC) can also be plugged in.
Cisco AS5X00: Cisco AS5X00 family of access servers support both analog modem and ISDN dial services. It is ideal where large number of remote users want to access the central site using dial up or ISDN services.

3. Cisco 7000 series: These are high end routers that supports combination of Ethernet, Fast Ethernet, Token Ring, FDDI, ATM, serial, ISDN etc.

The selection of equipment depends on the number of computers situated at the central site, type of applications that are being used, the number of remote connections from branch offices/home offices/telecommuter sites, and the bandwidth requirements.

1.1 Cisco recommends the following router equipment for branch office:

Series 1600: Cisco 1600 series includes Cisco 1601 through Cisco 1605. Each router has one empty network module slot.

Series 1700: Cisco 1700 series include Cisco 1720. It has one 10/100 Ethernet interface and two WAN slots.

Series 2500: Cisco 2500 series include Cisco 2501,2502. These routers are typically fixed configuration with any combination of the Ethernet, Token Ring, synchronous serial, ISDN BRI, and Hub (at least two of these interfaces are present).

Series 2600: Cisco 2600 series includes Cisco 2610, and 2620 routers. Each router has two empty WAN slots and one empty network module slot.

Note that Cisco series 1600, 1700, 2500, and 2600 are recommended for branch office applications.

1.2 The following are recommended by Cisco for Telecommuter site:

Series 700 are easy to configure multiprotocol ISDN access routers.
Series 800 are fixed configuration routers with ISDN BRI and Ethernet interfaces. Cisco recommends these models for home office/telecommuter facility.

Note that Series 700/Series 800/ Series 1000 routers are recommended for home office/telecommuter facility.

2.0 Some important routers series and their configurations:

Series 800 are fixed configuration routers with one Ethernet interface and most models (Only Cisco 805 does not have ISDN BRI interface) have ISDN BRI interface. Cisco805 has Serial interface. Cisco803, 804, and 813 can also accommodate 2 POTS in addition to Ethernet and ISDN BRI.

Series 1000: These are also fixed configuration routers. Cisco1003, Cisco1004 have 1 ISDN BRI + 1 Ethernet interface. Cisco 1005 has one Ethernet + 1 serial (sync/async) interface.
Note that Cisco 700 series, 800 series, and 1000 series are recommended for telecommuter or home office.

Series 1600: Cisco 1600 series includes Cisco 1601 through Cisco 1605. Each router has one WAN slot. Models 1601,15602,1603,1604 have one Ethernet interface, whereas model 1605 has 2 Ethernet interfaces. Support is also provided for ISDN BRI (1603,1604), and serial interface (1601). Cisco1602 has 56/64K CSU/DSU interface.

Series 2500: Cisco 2500 series include Cisco 2501,2502 and several other models. These routers are of fixed configuration (except Cisco2524) with any combination of the Ethernet, Token Ring, synchronous serial, ISDN BRI, and Hub (at least two of these interfaces are present).

Series 2600: Cisco 2600 series includes Cisco 2610, 2611 and 2620, 2621 routers. Each router has two empty WAN slots and one empty network module slot. 2610 has 1 Ethernet interface, whereas 2611 has two Ethernet interfaces. 2620 has 1 Fast Ethernet interface, whereas 2621 has two Fast Ethernet interfaces. The major difference between 2610 and 2620 is that the later provides support for Fast Ethernet.

It is recommended that you practice configuration of routers using ConfigMaker, a free utility available at Cisco Website and free to download and use.

3.0 Router LEDs:

By observing the status of various LEDs on a Cisco router, the health of a router can be found quickly. However, if the LED status is OK, and the problem still remains, you need to consult the manufacturer documentation for troubleshooting. Other options include Cisco Website, CCO Website etc.

Important LEDs on a Cisco 1600 router are as follows:
1. System PWR: Green indicates that the DC power to the router is OK.
2. System OK: Green indicates that the router has booted properly.
3. WIC CD: Green indicates an active connection on the serial port of WAN interface card.
4. WIC ACT: Activity indicates an active connection on the serial port of WAN interface card.
5. LAN ACT: This indicates that data is being sent or received.
6. LAN COL: Frame collisions are indicated by a flashing yellow LED.

4.0 EIA-232 / RS 232:

In EIA/TIA-232 standard, signals can be grouped as below (Pin numbers are given assuming 25 pin connector cable):
A. Data Transfer Group:
TxD (pin 2 on DTE): Transmit Data - This represents data transmit from DTE to DCE (Note the reference is DTE)
RxD (pin 3 on DTE): Receive Data - This represents data received from DCE to DTE (Again note the reference is DTE)
GRD (pin 7 on DTE)
B. Flow Control Group:
RTS (pin 4): Request To Send - Represents that the DTE has buffer space available to receive data from the DCE.
CTS (pin 5): Clear To Send - Represents that the DCE has buffer space available to receive data from DTE.
C. Modem Control Group:
DTR: Data Terminal Ready - Represents that the DTE is ready to receive data.
CD (pin8) - Carrier Detect - Indicates that the DCE has detected carrier from remote DCE.
DSR (pin6): Data Set Ready - It indicates that the DCE is ready to use.
If you are using a 25 pin connector on either end, and the cable is straight through, there is one to one correspondence in the pin connections. That is pin 2 of DTE is connected to pin 2 of DCE, pin 3 of DTE is connected to pin 3 of DCE etc. However, if you are using 25 pin connector at one end and 9 pin connector at the other end, the pin numbers change.

5.0 Null Modem:

In normal course, a DTE device is expected to communicated with a DCE device. In such event, the connections between the DCE and DTE devices is straight. However, if the communication need to happen between two DTEs or two DCEs (Null Modem), the signals need to be rolled. This is achieved by rolling the pins in the cable or in the DB-25 adapter. Typically, a DTE to DTE communication can be achieved by:

1. By connecting DTE to a rolled RJ-45 cable to a straight DB-25 adapter to DTE, OR

2. By connecting a straight RJ-45 cable to a rolled DB-25 adapter to DTE.

Similarly, a DTE to DCE communication can be achieved by:

1. Connecting a DTE to a straight RJ-45 cable to a straight DB-25 adapter to DCE, OR

2. Connecting a rolled RJ-45 cable to a rolled DB-25 adapter to DCE.
Note that rolling the signals twice is same as using straight through cables or adapters without any rolling at all.

Cram Notes 5:Cisco Certified Network Associate CCNA

51.Routing metrics used by IGRP:

Bandwidth, MTU, Reliability, Delay, and Load.

1. Bandwidth: This is represents the maximum throughput of a link.

2. MTU (Maximum Transmission Unit): This is the maximum message length that is acceptable to all links on the path. The larger MTU means faster transmission of packets.

3. Reliability: This is a measurement of reliability of a network link. It is assigned by the administrator or can be calculated by using protocol statistics.

4. Delay: This is affected by the band width and queuing delay.

5. Load: Load is based among many things, CPU usage, packets processed per sec.

52. The metric limit for link-state protocols is 65,533

53. Following are the possible solutions for preventing routing loops.

1. Split Horizon - based on the principle that it is not useful to send the information about a route back in the direction from which the information originally came.

2. Poison Reverse - A router that discovers an inaccessible route sets a table entry consistent state (infinite metric) while the network converges.

3. Hold-down Timers - Hold down timers prevent regular update messages from reinstating a route that has gone bad. Here, if a route fails, the router waits a certain amount of time before accepting any other routing information about that route.

4. Triggered Updates - Normally, new routing tables are sent to neighboring routers at regular intervals (IP RIP every 30 sec / and IPX RIP every 60 sec). A triggered update is an update sent immediately in response to some change in the routing table. Triggered updates along with Hold-down timers can be used effectively to counter routing loops.

54. IP RIP based networks send the complete routing table during update. The default update interval is 30 seconds. IGRP update packet is sent every 90 seconds by default.

55. For IGRP routing, you need to provide the AS (Autonomous System) number in the command. Routers need AS number to exchange routing information. Routers belonging to same AS exchange routing information. OSPF, and IGRP use AS numbers.

56. CDP stands for Cisco Discovery Protocol. This protocol is proprietary of Cisco. CDP runs SNAP (Sub network Access Protocol) at the Data Link Layer. Two Cisco devices running two different Network layer protocol can still communicate and learn about each other.

57. Show IP protocol: This command will show information on RIP timers including routing update timer (30sec default), hold-down timer (default 180sec). It also displays the number of seconds due for next update (this is fraction of update timer). This command also gives the network number for which IP RIP is enabled, Gateway, and the default metric.

1. Show IP route: This command will display the IP routing table entries. In addition, it displays the Gateway of last resort (if one is assigned). It also displays the codes used for various types of routes. Some of the important codes are:

C: directly connected;

S: Statically connected

I : IGRP

R : RIP

2. Show IP interface: This command shows you interface-wise information such as IP address assigned to each interface, whether the interface is up, MTU etc.

3. Debug IP RIP: Debug IP RIP will turn the RIP debugging ON. This will display a continuous list of routing updates as they are sent and received. This leads to lot of overhead, which is the reason that you use "undebug ip rip" to turn-off debugging as soon as you finish with debugging.

58. Cisco router boot configuration commands:

1. boot system - This is a global command that allows you to specify the source of the IOS software image to load. If you configure more than one source, attempts are made to load the IOS from the first command in the configuration to the last successively. If the first fails, the second boot command is used.

2. boot system rom - Loads IOS from ROM.

3. boot system flash - Loads the first file from flash memory.

4. boot system tftp <> - Loads IOS with a filename from a TFTP server.

Cram Notes 4:Cisco Certified Network Associate CCNA

40. There are five different types of passwords:

1. ENABLE PASSWORD - A global command that restricts access to privileged exec mode. This is a non-encrypted password.

2. ENABLE SECRET - Assigns a one-way encryptographic secret password, available in versions 10.3 and up. This secret password is used instead of the enable password when it exists.

3. Virtual Terminal Password (vty password): The virtual terminal password is used for Telnet sessions into the router. The password can be changed at any time. It can be set up when you configure the router from the console. There can be five distinct passwords corresponding to each vty (vty0 to vty4) or there can be a single password for all vtys.

4. Auxiliary Password: Auxiliary password is used to set password to the auxiliary port. This port is used to access a router through a modem.

5. Console Password: Console password is used to set the console port password.

41. Internal memory components of a Cisco router:
. ROM (Read Only Memory); Memory containing micro-code for basic functions to start and maintain the router. ROM is not typically used after the IOS is loaded.

2. RAM/DRAM : stores the running configuration, routing tables, and packet buffers. Some routers, such as the 2500 series, run IOS from Flash, not RAM.

3. NVRAM (Non-Volatile Ram): Memory that does not lose information when power is lost. Stores the system’s configuration file and the configuration register. NVRAM uses a battery to maintain the data when power is turned off.

4. Flash Memory: Stores the compressed IOS (IOS stands for Cisco Internetwork Operating System) image. Flash memory is either EEPROM or PCMCIA card. Flash memory enables you to copy multiple versions of IOS software. This allows you to load a new level of the operating system in every router in your network and then, to upgrade the whole network to that version at an appropriate time.

42. While a packet travels through an Internetwork, it usually involves multiple hops. Note that the logical address (IP address) of source (that created the packet) and destination (final intended destination) remain constant, the hardware (Interface) addresses change with each hop.

43. Default administrative distances some important routing protocols are as below:

Route Source Default Distance

Directly connect Interface 0

Static Route 1

IGRP 100

RIP 120

Unknown 255

An administrative distance of 0 represents highest trustworthiness of the route.

An administrative distance of 255 represents the lowest trustworthiness of the route.

Routed and Routing protocols:

- Routing protocols job is to maintain routing tables and route packets appropriately. Examples of routing protocols are RIP, IGRP, EIGRP, OSPF. Routers can support multiple independent routing protocols and can update and maintain routing tables for each protocol independently.

- Routed protocols are used to transport user traffic from source node to destination node. Examples of routed protocols are IP, IPX, AppleTalk.

44. There are three ways a router learns how to forward a packet:

1. Static Routes - Configured by the administrator manually. The administrator must also update the table manually every time a change to the network takes place. Static routes are commonly used when routing from a network to a stub (a network with a single route) network.

The command is

ip route network mask address/interface [distance]

ex: ip route 165.44.34.0 255.255.255.0 165.44.56.5

Here, 165.44.34.0 is the destination network or subnet

255.255.255.0 is the subnet mask

165.44.56.5 is the default gateway.

2. Default Routes - The default route (gateway of last resort) is used when a route is not known or is infeasible. The command is

ip route 0.0.0.0 0.0.0.0 165.44.56.

The default gateway is set to 165.44.56.5

3. Dynamic Routes - In dynamic routing, the routing tables are automatically updated. Dynamic routing uses broadcasts and multicasts to communicate with other routers.

The commands to enable rip are:

router rip

network .

45. To enable the Cisco IOS to forward packets destined for obscure subnets of directly connected networks onto the best route, you use "ip classless" command.

46. There are broadly three types of routing protocols:

1. Distance Vector (Number of hops) - Distance vector routing determines the direction (vector) and distance to any link in the internetwork. Typically, the smaller the metric, the better the path. EX: Examples of distance vector protocols are RIP and IGRP. Distance vector routing is useful for smaller networks. The limitation is that any route which is greater than 15 hops is considered unreachable. Distance vector protocols listen to second hand information to learn routing tables whereas, Link state protocols build routing tables from first hand information. Routers with distance vector protocols send its entire routing table to each of its adjacent neighbors.

2. Link State Routing: Link State algorithms are also known as Shortest Path First (SPF) algorithms. SPF generates the exact topology of the entire network for route computation, by listening to the first hand information. Link State protocols take bandwidth into account using a cost metric. Link State protocols only send updates when a change occurs, which makes them more efficient for larger networks. Bandwidth and delay are the most widely used metrics when using Link-State protocols. EX: OSPF and NLSP.

Benefits of Link State protocols:

1. Allows for a larger scalable network

2. Reduces convergence time

3. Allows “supernetting”

3. Balanced Hybrid - Balanced Hybrid combines some aspects of Link State and Distance Vector routing protocols. Balanced Hybrid uses distance vectors with more accurate metrics to determine the best paths to destination networks. EX: EIGRP.

47. Distance vector protocol depends only on Hop count to determine the nearest next hop for forwarding a packet. One obvious disadvantage is that, if you have a destination connected through two hops via T1 lines, and if the same destination is also connected through a single hop through a 64KBPS line, RIP assumes that the link through 64KBPS is the best path!

48. RIP (and IGRP) always summarizes routing information by major network numbers. This is called classfull routing.

49. Convergence is the term used to describe the state at which all the internetworking devices, running any specific routing protocol, are having identical information about the internetwork in their routing tables. The time it takes to arrive at identical information of the internetwork is called Convergence Time.

50. RIP,RIP2, and IGRP use distance vector algorithms.

RIP2 transmits the subnet mask with each route. This feature allows VLSM (Variable Length Subnet Masks) by passing the mask along with each route so that the subnet is