RouterStuff: CCNA Practice

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Selasa, 07 Desember 2010

Cram Exam 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 Exam 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

Cram Exam Notes 3 Cisco Certified Network Associate CCNA

31. Ethernet_II has a type field to identify the upper-layer protocol. 802.3 has only a length field and can't identify the upper-layer protocol.

32.To find valid hosts given an IP address (say 156.16.3.52) and a subnet mask (sat a 12-bit subnet). The valid hosts are determined as below:

A 12-bit subnet mask gives us 255.255.255.240; 4094 subnets, each with 14 hosts. (Host addresses of all zeros and all 1s can't be assigned). The 156.16.3.52 is in the 48 subnet range. The valid range is through 49 - 62. 63 is a broadcast address.

Here is how you get the subnet range:

1. Find the subnet mask. In this case, default subnet mask for Class B address is 255.255.0.0. There are additional; 12 bits in the subnet mask. Now the subnet mask looks like:

11111111.11111111.11111111.11110000. This is equal to 255.255.255.240.0.

2. Now, deduct the lowest value octet (Which is non zero), from 256. Here, (256-240)=16.

This is the value that the subnets are incremented. Therefore, you will have hosts with values from:

156.16.3.1 to 156.16.3.14 (All 0s and all 1s host addresses can not be used)

156.16.3.17 to 156.16.3.30

156.16.3.33 to 156.16.3.46

156.16.3.49 to 156.16.3.62 and so on.

It is important to know that subnets are incrementing here by a factor of 16.

33. The following are some important commands that can be used to edit and review command history buffer on a Cisco router. It will be useful to practice these commands.

A : Move to the beginning of the command line

E : Move to the end of the command line

F : Move forward one character, same as using "Right Arrow".

B : Move backward one character, same as using "Left Arrow".

P : Repeat Previous command, same as using "Up Arrow".

N : Repeat Next (more recent) command, same as using "Down Arrow".

B : Moves to beginning of previous word.

F : Moves to beginning of next word.

R : Creates new command prompt, followed by all the characters typed at the last one.

34. The following are some frequently used COPY commands:

COPY RUNNING-CONFIGURATION STARTUP-CONFIGURATION (alternatively, you can use an older version of the command, WRITE MEMORY): This command saves the current configuration to NVRAM. Alternatively, we can issue the command using short form: COPY RUNNING STARTUP - Copies configuration from RAM to NVRAM
COPY STARTUP RUNNING - This command merges configuration from NVRAM to RAM.
COPY FLASH TFTP - Copies current IOS from router flash memory to TFTP server.
COPY TFTP FLASH - Copies image file from TFTP server to flash. This is used to upgrade the IOS image file to a newer version, or if your IOS image becomes corrupt.

35. The banner is displayed whenever anyone logs in to your Cisco router. The syntax is

- "banner motd # " . MOTD stands for "Message Of The Day".

# symbol signifies the start of the banner message to the router. You will be prompted for the message to be displayed. You need to enter "#" symbol at the end of the message, signifying that the message has ended.

36. Router modes of operation:

1. User EXEC mode (Prompt: Router>):- This is the LOWEST level of access. This allows examination of router status, see routing tables, and do some diagnostics. However, you cannot change the router configuration, view the configuration files, or control the router in any way. The prompt in this mode is "Router>".

2. Privileged (enable) EXEC mode (Prompt: Router#):- This mode allows you to have all the privileges of EXEC (user) mode plus commands that enable you to view configuration files, change the router configuration, perform troubleshooting that could potentially disrupt traffic. The default prompt for this mode is "Router#".When you are working in the privileged mode (at # prompt), you can get back to user mode by typing "disable" at the "#" prompt.

3. Global Configuration mode (Prompt: Router (Config)#):-

Global configuration mode allows you to perform tasks that affect the entire router, such as naming the router, configuration of banner messages, enabling routed protocols, and generally anything that affects the operation of the entire router.

When you first switch on a router, you enter Setup mode. Setup mode is different from configuration mode in that setup mode appears when there is no configuration file present. Upon entering setup mode, you can supply some basic configuration parameters to Cisco router.

37. You can use "tab" to complete the command that you are typing.

38. SHOW command is extensively used for seeing the status and configuration information of the router.

Some of the frequently used commands are:

1. SHOW RUNNING-CONFIGURATION -This command displays the router's active configuration file, passwords, system name, and interface settings, interfaces IP addresses etc.

2. SHOW INTERFACE - Shows status and configuration information of the local interfaces. The first line says something like “TokenRing1 is up, line protocol is up”. The first part “TokenRing1 is up” describes the physical layer components such as electrical cabling and signaling are OK. The second part “line protocol is up” means that the router is detecting keep-alive messages. The router may be put into administratively down status, at which point the line would read, “TokenRing1 is administratively down, line protocol is down.”

3. SHOW INTERFACE SERIAL 0 - Shows the serial 0 configuration.

4. SHOW INTERFACES - Displays statistics for all interfaces configured on the switch.

5. SHOW PROCESS - Displays a router’s CPU utilization.

6. SHOW CONFIG - Displays information on the startup configuration.

7. SHOW VERSION - Displays information about the system hardware (RAM/ROM), software version, names of configuration files, and boot-images. This command will also show the current configuration register value.

39. The Cisco router can be configured from many locations.

1. Console port: During the initial installation, you configure the router from a console terminal connected to the "Console port" of the router.

2. Virtual Terminals (vty): A virtual terminal (vty) is typically accessed through Telnet. A router can be accessed through vty after it the initial installation in the network. There are five virtual terminals, namely, vty0,vty1,vty2,vty3,vty4.

3. Auxiliary Port: you can configure a router through auxiliary port. Typically, a modem is used to configure the modem through aux port.

4. TFTP Server: Configuration information can be downloaded from a TFTP server over the network.

5. NMS (Network Management Station): You can also manage router configuration through NMS such as CiscoWorks or HP OpenView.

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.

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.

Cram Exam Notes 2 Cisco Certified Network Associate CCNA

12. Telnet, FTP, and TFTP:

1. Telnet is used for terminal emulation that runs programs remotely. Telnet uses TCP/IP protocol.

2. Telnet requires a username and password to access.

3. FTP (File Transfer Protocol) is a connection oriented protocol. It uses TCP/IP for file transfer. Compare this with TFTP (Trivial File Transfer Protocol) that uses UDP (Connectionless protocol). SNMP uses UDP over IP. Tracert, Ping use ICMP as their base protocol. FTP is used to transfer files.

13. Maximum hop count supported by RIP is 15.

14. The port numbers used by different programs are as below:

I. FTP : Port #21

II. Telnet: Port #23

III. SMTP: Port #25

IV. SNMP: Port #161

It is important to know that FTP, Telnet, SMTP use TCP; whereas TFTP, SNMP use UDP.

15. SNMP is part of TCP/IP protocol suite. It allows you to monitor and manage a network from a centralized place by using SNMP Manager software. The systems or devices that provide the responses are called agents (or MIBs). An SNMP agent is any computer running SNMP agent software.

MIB stands for Management Information Base. It is part of SNMP agent database. A MIB records and stores information abut the host it is running on. An SNMP manager can request and collect information from an agent's MIB. Routers are typical MIB agents. SNMP agent generates "trap" messages that are then sent to an SNMP management console, which is a trap destination.

17. Address Resolution Protocol (ARP) is used to resolve or map a known IP address to a MAC sub layer address to allow communication on a multi-access medium such as Ethernet. Reverse ARP (RARP) is used to obtain an IP address using an RARP broadcast. RARP can be used to boot diskless workstations over a network.

18. The 7 layers of OSI model are:

1. The Application Layer: Application layer is responsible for identifying and establishing the availability of desired communication partner and verifying sufficient resources exist for communication. Some of the important application layer protocols are: WWW, SMTP, FTP, etc.

2. The Presentation Layer: This layer is responsible for presenting the data in standard formats. This layer is responsible for data compression, decompression, encryption, and decryption. Some Presentation Layer standards are: JPEG, MPEG, MIDI, PICT, Quick Time, TIFF.

3. The Session Layer: Session Layer is responsible for co-ordinating communication between systems/nodes. The following are some of the session layer protocols and interfaces: a) Network File System (NFS), SQL, RPC (Remote Procedure Call), X-Windows, ASP, DNA SCP.

4. The Transport Layer: The Transport Layer is responsible for multiplexing upper-layer applications, session establishment, and tearing-down of virtual circuits. This layer is responsible for flow control, to maintain data integrity.

5. The Network Layer: There can be several paths to send a packet from a given source to a destination. The primary responsibility of Network layer is to send packets from the source network to the destination network using a pre-determined routing methods. Routers work at Network layer.

6. The Data Link Layer:

Data Link Layer is layer 2 of OSI reference model. This layer is divided into two sub-layers:

A. Logical Link Control (LLC) sub-layer.

B. Media Access Control (MAC) sub-layer.

The LLC sub-layer handles error control, flow control, framing, and MAC sub-layer addressing.

The MAC sub-layer is the lower of the two sub-layers of the Data Link layer. MAC sub-layer handles access to shared media, such a Token passing or Ethernet.

7. Physical Layer: The actual flow of signals take place through Physical layer. At Physical layer, the interface between the DTE and DCE is determined. The following are some of the standard interfaces are defined at Physical layer: EIA/TIA-232, EIA/TIA-449,V.24,V.35,X.21,G.703,HSSI (High Speed Serial Interface).

19. Repeaters, Bridges, and Routers:

I. Repeaters work at Physical layer (Layer 1),

II. Bridges and simple switches work at Data Link Layer (Layer 2),

III. Routers work at Network Layer (Layer 3) of ISO Reference Model. 20. CSU / DSU is an acronym for Channel Service Unit / Data Service Unit. CSU/DSU is part of Customer Premise Equipment (CPE). CSU / DSU connect to a Central Office (CO), a telephone switching company located nearer to the customer.

Cram Exam Notes Cisco Certified Network Associate CCNA

About CCNA Exam: CCNA Certification is offered by Cisco®. CCNA tests your knowledge and skills in the areas of simple LAN/WAN switching, Cisco IOS, and routing technologies. Topics include TCP/IP model of internetworking, configuring, and troubleshooting RIP, RIP v2, IGRP, EIGRP, OSPF, NAT, Remote Access using some of the most widely used Cisco switches and routers. Please visit the Cisco website for current objectives. Two recommended resources for Cisco certification preparation are Cisco Press "Cisco CCNA Preparation Library" and CCNA by Sybex. There are many others that are very good, but not widely known. CCNA is the foundation exam for CCNP (Cisco Certified Networking Professional). The exam notes is a brief review of important points that help in quick review of key points.

Cram Notes:
1. Internetwork IP addressing:

IP addresses are written using decimal numbers separated by decimal points. This is called dotted decimal notation of expressing IP addresses.

The different classes of IP addresses is as below:

Class	Format	Leading Bit pattern	Network address Range	Maximum networks	Maximum hosts/ nodes
A	N.H.H.H	0	0-126	127	16,777,214
B	N.N.H.H	10	128-191	16,384	65,534
C	N.N.N.H	110	192-223	2,097,152	254

- Network address of all zeros means "This network or segment".

- Network address of all 1s means " all networks", same as hexadecimal of all Fs.

- Network number 127 is reserved for loop-back tests.

- Host (Node) address of all zeros mean "This Host (Node)".

- Host (Node) address of all 1s mean "all Hosts (Nodes) " on the specified network.

2. The range of numbers from 224.0.0.0 to 239.255.255.255 are used for multicast packets. This is known as Class D address range.
3. Subnetting is nothing but creating networks within a network. Subnetting allows an organization with a single IP address (Class A /ClassB /ClassC) to have multiple subnetworks, thus allowing several physical networks within the organization.

4. How to maximize the number of subnets for a given number of hosts:

Let us take a network ID of 168.8.0.0, and find the maximum number of possible subnets and the corresponding subnet mask that can accommodate at least 500 hosts. The steps involved are outlined below:

I. Find the Class of the IP address, in this case it is a class B network. Class B network has the form N.N.H.H. Therefore, we have a total of 16 bits (two octets) for assigning to internal networks and hosts. The minimum number of host addresses required is 500. The last octet corresponds to 2^8 = 256 hosts which is still less than 500 Hosts.. Therefore, you have to borrow one more bit from the third octet to make it 256*2 = 512 Hosts. This leaves 7 bits in the third octet for assigning subnet addresses. This is equal to 2^7=128 subnets.

II. Write the 7 bits available for subnetting in third octet in the form 11111110 (last bit being the Host bit). The decimal equivalent of the first seven bits is 2^7+2^6+2^5+2^4+2^3+2^2+2^1

= 128 + 64 +32 + 16 + 8 + 4 + 2 = 254.

III. Therefore, the subnet mask required is 255.255.254.0.

6. How to maximize the number of hosts for a given number of subnets:

Determining the subnet mask that allows maximum number of hosts:

Let us consider an IP address 196.202.56.0 with four subnets and maximize the number of host for the given subnets. The steps involved are as below:

I. The number of subnets required are four. We need to add subnets of all ones and all zeros to this. This is because all zeros and all ones subnets belong to "this subnet" and "all subnets" broadcasts and can not be used. Therefore, the total number of subnets to be reserved is 4+2 = 6.

II. We want to implement maximum possible Hosts. Therefore, we need to minimize the number of subnets. This minimum number is 6 here. If we reserve 2 bits, it results in only 2^2=4 subnets which is less than 6. Therefore, we have to reserve 3 bits for implementing subnets, resulting in 2^3=8 subnets. This is now optimized for maximum number of Hosts (as we have optimized for minimum number of subnets).

III. Write the 3 bits available for subnetting in fourth octet in the form 11100000 (Five 0s being Host bits). The decimal equivalent is 2^7+2^6+2^5

= 128 + 64 +32 = 224.

IV. Therefore, the subnet mask required is 255.255.255.224.

7. 127.0.0.1 is the local loop back address.

8. In an internetwork, the number of distinct IPs' required are

1. One each per client computer

2. One each per server computer

3. One each per router interface.

For example, your network has 2 servers, 26 clients machines, and 2 router interfaces the total number of IP addresses required are 30.

9. Finding the number of Hosts and subnets available for a given subnet mask: For example, let us find the number of hosts and subnets available for an IP 156.233.42.56 with a subnet mask of 7 bits.

a. Class B network has the form N.N.H.H, the default subnet mask is 16 bits long. There is additional subnet mask of 7 bits long.

b. 7 bits of subnet mask corresponds to (2^7-2)=128-2 = 126 subnets.

c. 9 bits (16-7) of host addresses corresponds to (2^9-2)=512-2 = 510 hosts.

Some times, the subnet mask is specified with the bits available in the default subnet mask. In this case the bits available in default subnet mask is 16. Therefore, total number of bits available in the subnet mask are 16+7=23. If you are given a subnet mask of 23 bits long for a class B address, it is understood that it contains the bits from the default subnet mask as well.

Hence, 126 subnets and 510 hosts are available. 10. The directed broadcast should reach all Hosts on the intended network (or subnet, if sub netted). For example, the directed broadcast address for an IP network 196.233.24.15 with default subnet mask is 196.233.24.255. This is arrived by putting all 1s for the host potion of the IP address.

Kamis, 02 September 2010

CCNA2 Final Mar 2010: CCNA Cisco Routing Protocols and Concepts Final Exam Practice

1. What are two functions of a router? (Choose two.)

It connects multiple IP networks.

It controls the flow of data via the use of Layer 2 addresses.
It determines the best path to send packets.
It manages the VLAN database.
It increases the size of the broadcast domain

2. When a router boots, what is the default order to locate the Cisco IOS if there is no boot system command?
ROM, TFTP server, flash

flash, TFTP server, ROM

flash, NVRAM, TFTP server
NVRAM, TFTP server, flash

3. Which router component is used to store the routing table?
Flash
NVRAM
ROM

SDRAM

4. Refer to the exhibit. How many routes are child routes?
1
3

6

5. Refer to the exhibit. Which statement is true concerning the routing configuration?
Using dynamic routing instead of static routing would have required fewer configuration steps.
The 10.1.1.0/24 and 10.1.2.0/24 routes have adjacent boundaries and should be summarized.

Packets routed to the R2 Fast Ethernet interface require two routing table lookups.

The static route will not work correctly

6. Refer to the exhibit. The network administrator issues the command no ip classless on Router1. What forwarding action will take place on a packet that is received by Router1 and is destined for host 192.168.0.26?

The packet will be dropped.

The packet will be forwarded to the gateway of last resort.
The packet will match the 192.168.0.0 network and be forwarded out Serial 0/0.
The packet will most closely match the 192.168.0.8 subnet and be forwarded out Serial 0/1

7. Refer to the exhibit. Routers R1 and R3 use different routing protocols with default administrative distance values. All devices are properly configured and the destination network is advertised by both protocols.

Which path will be used to transmit the data packets between PC1 and PC2?

The packets will travel via R2-R1.

The packets will travel via R2-R3.
The traffic will be load-balanced between two paths — via R2-R1 and via R2-R3.
The packets will travel via R2-R3, and the other path via R2-R1 will be retained as the backup path

8. Refer to the exhibit. Router R1 is configured as shown in the exhibit. PC1 on 172.16.1.0/24 network can reach the default gateway on R1. The rest of the routers are configured with the correct IP addresses on the interfaces. Routers R2 and R3 do not have static or dynamic routing enabled. How far will PC1 be able to successfully ping?
router R1 Fa0/0 interface

router R1 S0/0/0 interface

router R2 S0/0/0 interface
router R2 Fa0/0 and S0/0/1 interfaces
router R3 Fa0/0 and S0/0/0 interfaces

9. Refer to the exhibit. All routers are properly configured to use the EIGRP routing protocol with default settings, and the network is fully converged. Which statement correctly describes the path that the traffic will use from the 10.1.1.0/24 network to the 10.1.2.0/24 network?
It will use the A-D path only.
It will use the path A-D, and the paths A-C-D and A-B-D will be retained as the backup paths.
It will use all the paths equally in a round-robin fashion.

The traffic will be load-balanced between A-B-D and A-C-D.

10. Which two statements are true regarding link-state routing protocols? (Choose two.)

They are aware of the complete network topology.

They offer rapid convergence times in large networks.

They do not include subnet masks in their routing updates.
They rely on decreasing hop counts to determine the best path.
They do not work well in networks that require special hierarchical designs.
They pass their entire routing tables to their directly connected neighbors only

11. Refer to the exhibit. R1 knows two routes, Path A and Path B, to the Ethernet network attached to R3. R1 learned Path A to network 10.2.0.0/16 from a static route and Path B to network 10.2.0.0/16 from EIGRP. Which route will R1 install in its routing table?
Both routes are installed and load balancing occurs across both paths.
The route via Path B is installed because the EIGRP route has the best metric to network 10.2.0.0/16.
The route via Path A is installed because the static route has the best metric to network 10.2.0.0/16.
The route via Path B is installed because the EIGRP route has the lowest administrative distance to network 10.2.0.0/16.

The route via Path A is installed because the static route has the lowest administrative distance to network 10.2.0.0/16.

12. What two routing protocols use a hierarchal network topology? (Choose two.)

IS-IS

EIGRP

OSPF

RIPv1
RIPv2

13. Refer to the exhibit. Based on the output from the show running-config and debug ip rip commands, what are two of the routes that are added to the routing table of R1? (Choose two.)

R 192.168.1.0/24 [120/1] via 172.16.2.1, 00:00:24, Serial0/0/1

R 192.168.100.0/24 [120/1] via 172.16.1.1, 00:00:24, Serial0/0/0

S 192.168.1.0/24 [1/0] via FastEthernet0/0

R 192.168.9.0/24 [120/1] via 172.16.2.1, 00:00:24, Serial0/0/0
R 192.168.2.0/24 [120/1] via 172.16.1.2, 00:00:24, Serial0/0/0

14. Refer to the exhibit. The network has three connected routers: R1, R2 and R3. The routes of all three routers are displayed. What can be verified from the output?

R1 and R3 are connected to each other via the S0/0/0 interface.
The IP address of the S0/0/0 interface of R1 is 10.1.1.2.
The IP address of the S0/0/1 interface of R2 is 10.3.3.2.

R2 is connected to the S0/0/1 interface of R3.

15. Refer to the exhibit. All router interfaces are configured with an IP address and are operational. If no routing protocols or static routes are configured, what information will be included in the show ip route command output for router A?

All of the 192.168.x.0 networks will be in the routing table.

Routes to networks 192.168.1.0/24, 192.168.2.0/24, and 192.168.3.0/24 will be in the routing table.

The routing table will be empty because routes and dynamic routes have not been configured.
A default route is automatically installed in the routing table to allow connectivity between the networks.

16. Refer to the exhibit. A network administrator is accessing router R1 from the console port. Once the administrator is connected to the router, which password should the administrator enter at the R1> prompt to access the privileged EXEC mode?

Cisco001
Cisco123

Cisco789

Cisco901

17. Which of the following could describe the devices labeled "?" in the graphic? (Choose three.)

DCE

CSU/DSU

LAN switch

modem

hub

18. Refer to the exhibit. Which router is advertising subnet 172.16.1.32/28?

Router1
Router2
Router3

Router4

19. Refer to the exhibit. The show cdp neighbors command was run at R1. Which two facts about the newly detected device can be determined from the output? (Choose two.)

ABCD is a router that is connected to R1.

ABCD is a non-CISCO device that is connected to R1.

The device is connected at the Serial0/0/1 interface of R1.

R1 is connected at the S0/0/1 interface of device ABCD.
ABCD does not support switching capability.

20. A static route has been configured on a router. However, the destination network no longer exists. What should an administrator do to remove the static route from the routing table?
Change the routing metric for that route.
Nothing. The static route will go away on its own.
Change the administrative distance for that route.

Remove the route using the no ip route command.

21. Refer to the exhibit. A ping between host A and host B is successful, but pings from host A to operational hosts on the Internet fail. What is the reason for this problem?

The FastEthernet interface of R1 is disabled.

One of the default routes is configured incorrectly.

A routing protocol is not configured on both routers.
The default gateway has not been configured on host A.

22. Refer to the exhibit. The network has three connected routers: R1, R2, and R3. The routes of all three routers are displayed. All routers are operational and pings are not blocked on this network.

Which ping will fail?

from R1 to 172.16.1.1

from R1 to 192.168.3.1

from R2 to 192.168.1.1
from R2 to 192.168.3.1

23. Refer to the exhibit. What action will R2 take for a packet that is destined for 192.168.2.0?
It will drop the packet.

It will forward the packet via the S0/0/0 interface.
It will forward the packet via the Fa0/0 interface.

It will forward the packet to R1

24. Refer to the exhibit. The users on the local network 172.16.1.0/24 complain that they are unable to connect to the Internet. What step should be taken to remedy the problem?

A new static route must be configured on R1 with the R3 serial interface as the next hop.
A new default route must be configured on R1 with the R3 serial interface as the next hop.
The default route on R2 should be configured with the R3 serial interface as the next hop.
The default route on R2 must be replaced with a new static route and the next hop should be the R1 FastEthernet interface

25. Refer to the exhibit. What summary address can Router2 advertise to Router1 to reach the three networks on Routers 3, 4, and 5 without advertising any public address space or overlapping the networks on Router1?

172.16.0.0/8
172.16.0.0/10

172.16.0.0/13

172.16.0.0/20
172.16.0.0/24

26. Refer to the exhibit. Host A is unable to access the Internet, and troubleshooting has revealed that this is due to an addressing problem. What is incorrectly configured in this network?

the IP address of the Fa0/0 interface of R1
the subnet mask of the S0/0/0 interface of R1

the IP address of the S0/0/0 interface of R1

the subnet mask of the S0/0/0 interface of R2

27. Refer to the exhibit. A new PC was deployed in the Sales network. It was given the host address of 192.168.10.31 with a default gateway of 192.168.10.17. The PC is not communicating with the network properly. What is the cause?

The default gateway is incorrect.
The address is in the wrong subnet.
The host address and default gateway are swapped.

192.168.10.31 is the broadcast address for this subnet

28. Refer to the exhibit. The network administrator is planning IP addressing of a new network. What part of this addressing scheme must be changed to allow communication between host A and the server?

the IP address of the server

the default gateway of host A
the IP address of host A
the default gateway of the server

29. Which network design feature requires the deployment of a classless routing protocol?
private IP addressing
advertising default routes

variable length subnet masks

summarization on major network boundaries

30. A network administrator needs to assign the very last usable IP address in the 172.24.64.0/18 network range to the router interface that serves this LAN. Which IP address should the administrator configure on the interface?
172.16.128.154/18
172.16.255.254/18
172.24.64.254/18

172.24.127.254/18

31. Refer to the exhibit. All routers are running RIPv1. The two networks 10.1.1.0/29 and 10.1.1.16/29 are unable to access each other. What can be the cause of this problem?

Because RIPv1 is a classless protocol, it does not support this access.

RIPv1 does not support discontiguous networks.

RIPv1 does not support load balancing.
RIPv1 does not support automatic summarization.

32. Refer to the exhibit. What information can be determined from the highlighted output?

R1 is originating the route 172.30.200.32/28.

Automatic summarization is disabled.

The 172.30.200.16/28 network is one hop away from R1.
A classful routing protocol is being used

33. What does RIP use to reduce convergence time in a larger network?
It uses multicast instead of broadcast to send routing updates.
It reduces the update timer to 15 seconds if there are more than 10 routes.

It uses triggered updates to announce network changes if they happen in between the periodic updates.

It uses random pings to detect if a pathway is down and therefore is preemptive on finding networks that are down

34. A network administrator has enabled RIP on routers B and C in the network diagram. Which of the following commands will prevent RIP updates from being sent to Router A?

A(config)# router rip
A(config-router)# passive-interface S0/0
B(config)# router rip
B(config-router)# network 192.168.25.48
B(config-router)# network 192.168.25.64
A(config)# router rip
A(config-router)# no network 192.168.25.32

B(config)# router rip

B(config-router)# passive-interface S0/0

A(config)# no router rip

35. Refer to the exhibit. Both routers are using the RIP protocol. Devices on the 192.168.1.1 network can ping the S0/0/0 interface on R2 but cannot ping devices on the 192.168.2.1 network.

What is a possible cause of this problem?

The routers are configured with different versions of RIP.

R2 is not forwarding the routing updates.
The R1 configuration should include the no auto-summary command.
The maximum path number has been exceeded.

36. Which two statements are correct about the split horizon with poison reverse method of routing loop prevention? (Choose two.)
It is enabled by default on all Cisco IOS implementations.

It assigns a value that represents an infinite metric to the poisoned route.

It sends back the poisoned route update to the same interface from where it was received.

It instructs routers to hold all changes that might affect routes, for a specified period of time.
It limits the number of hops a packet can traverse through the network before it is discarded

37. Refer to exhibit. Given the topology shown in the exhibit, what three commands are needed to configure EIGRP on the Paris router? (Choose three.)

Paris(config)# router eigrp 100

Paris(config)# router eigrp
Paris(config-router)# network 192.168.6.0

Paris(config-router)# network 192.168.7.0

Paris(config-router)# network 192.168.8.0

Paris(config-router)# network 192.168.9.0

38. A router has EIGRP configured as the only routing protocol. In what way might EIGRP respond if there is no feasible successor route to a destination network and the successor route fails?
It broadcasts hello packets to all routers in the network to re-establish neighbor adjacencies.

It sends queries to adjacent neighbors until a new successor route is found.

It immediately sends its entire routing table to its neighbors.
It will set the metric for the failed route to infinity.

39. Refer to the exhibit. Hosts on the BOS Fa0/0 LAN are able to ping the Fa0/1 interface on the JAX router and all interfaces on the BOS and ORL routers. Why would hosts from the 10.0.0.0/24 network not be able to ping hosts on the Fa0/0 LAN of the JAX router?

The JAX router has the wrong process ID.

The JAX router needs the network 10.0.0.0 0.0.0.255 area 0 command.

The JAX router needs the network 192.168.3.0 0.0.0.255 area 0 command.

The BOS router needs the network 192.168.3.0 0.0.0.255 area 0 command

40. Which three statements describe the operation of routing with EIGRP? (Choose three.)

As new neighbors are discovered, entries are placed in a neighbor table.

If the feasible successor has a higher advertised cost than the current successor route, then it becomes the primary route.

If hello packets are not received within the hold time, DUAL must recalculate the topology.

The reported distance is the distance to a destination as advertised by a neighbor.

EIGRP maintains full knowledge of the network topology in the topology table and exchanges full routing information with neighboring routers in every update.
EIGRP builds one routing table that contains routes for all configured routed protocols.

41. Refer to the exhibit. What happens to a packet that has 172.16.0.0/16 as the best match in the routing table that is shown?

The packet is discarded.

The packet is flooded out all interfaces.
The packet is forwarded via Serial0/0/0.
The packet is forwarded via FastEthernet0/0.

42. A network is configured with the IP, IPX, and AppleTalk protocols. Which routing protocol is recommended for this network?
RIPv1
RIPv2

EIGRP

OSPF

43. Refer to the exhibit. Which two statements are true based on the exhibited output? (Choose two.)

Automatic summarization is disabled.

The EIGRP routing protocol is being used.

There is one feasible successor in the routing table.
The serial interface S0/0/0 is administratively down.
The router is originating the route to 172.16.1.0/24 via the S0/0/0 interface

44. Refer to the exhibit. Two routers are unable to establish an adjacency. What is the possible cause for this?

The two routers are connected on a multiaccess network.

The hello and dead intervals are different on the two routers.

They have different OSPF router IDs.
They have different process IDs

45. What command would the network administrator apply to a router that is running OSPF to advertise the entire range of addresses included in 172.16.0.0/19 in area 0?
R1(config-router)# network 172.16.0.0 0.0.0.255 area 0
R1(config-router)# network 172.16.0.0 0.0.3.255 area 0
R1(config-router)# network 172.16.0.0 0.0.15.255 area 0

R1(config-router)# network 172.16.0.0 0.0.31.255 area 0

46. What should be considered when troubleshooting a problem with the establishment of neighbor relationships between OSPF routers? (Choose two.)

OSPF interval timers mismatch

administrative distance mismatch

interface network type mismatch

no loopback interface configured
gateway of last resort not redistributed

47. Which two components are used to determine the router ID in the configuration of the OSPF routing process? (Choose two.)
the IP address of the first FastEthernet interface

the highest IP address of any logical interface

the highest IP address of any physical interface

the default gateway IP address
the priority value of 1 on any physical interface

48. What is the function of the OSPF LSR packet?
It is used to confirm the receipt of LSUs.
It is used to establish and maintain adjacency with other OSPF routers.

It is used by the receiving routers to request more information about any entry in the DBD.

It is used to check the database synchronization between routers.

49. Refer to the exhibit. All interfaces are configured with the correct IP addresses and subnet masks. OSPF has been configured as the routing protocol. During troubleshooting, it is determined that hosts on network B can ping the Lo0 interface on R1 but are unable to reach hosts on network A. What is the cause of the problem?

Routers R1 and R2 have incorrect router IDs configured.
Router R1 is unable to form a neighbor relationship with router R2.
Routers R1 and R2 have been configured in different OSPF areas.

The configuration of router R1 fails to include network A in the OSPF routing process

50. Refer to the exhibit. The interface addresses and OSPF priorities are configured as shown. Because of the boot order of the routers, router A is currently the DR and router B is the BDR. If router A fails and is replaced the next day by a new router, router D, what OSPF protocol action or actions will happen?

Router D will be elected DR, and router C will become the BDR.

Router D will be elected DR, and router B will remain the BDR.
Router C will become the DR, and router B will become the BDR.
Router B will remain the BDR, and OSPF will function on the segment via the use of only the BDR