50-100

QUESTION 50

Which type of network connection requires a straight-through cable?

  1. host to host
  2. switch to router
  3. switch to switch
  4. host to router’s Ethernet port

Correct Answer: B Section: (none) Explanation

Explanation/Reference:

Explanation:

A switch to router connection requires a straight-through cable. Straight-through cables are also used for host to switch communication.

A crossover cable is used to connect «like» devices, and a straight through cable is used when connecting «unlike» devices. The one exception to this rule is when connecting a computer NIC to an Ethernet port on a router, a crossover cable is used. In summary, the following list describes when to use crossover and straight through cables:

Host to host Crossover Host NIC to router Crossover

Host to switch Straight through Switch to Switch Crossover

Switch to router Straight through

The difference between straight-through and crossover lies in the location of the wire termination on the two ends of an RJ-45 cable. If the unshielded twisted-pair (UTP) cable wire connects Pin 1 of one side to Pin 1 of other side and Pin 2 to 2 through all eight Pins of the RJ-45 connector, the cable is said to be straight- through.

On the other hand, if the Pin 1 of one side RJ-45 cable connected to Pin 3 of other end and Pin 2 connects to Pin 6 of other side, it is called as crossover cable. The cable type to be used depends upon circuit connection on the hardware. Some devices have ports that are capable of identifying the cable type and automatically adjusting the port setting to be a standard or uplink port.

Host-to-host, switch-to-switch, and host-to-Ethernet-port would all use a crossover cable to connect in the network. The following figure shows the pin layout for a crossover cable:

Objective:

Network Fundamentals Sub-Objective:

Select the appropriate cabling type based on implementation requirements

References:

Cisco > Product Support > End-of-Sale and End-of-Life Products > Cisco 7000 Series Routers > Troubleshooting Technotes > Cabling Guide for Console and AUX Ports > Document ID: 12223

QUESTION 51

Which of the following statements describes split horizon?

  1. The router learns from its neighbor that a route has gone down, and the router sends an update back to the neighbor with an infinite metric to that route.
  2. For a period of time, the router will ignore any route advertisements with a lower metric to a downed route.
  3. A router will not send route information back out the same interface over which it was learned.
  4. The moment a router determines a route has gone down, it will immediately send a route update with an infinite metric to that route.
  5. The packets are flooded when a topology change occurs, causing network routers to update their topological databases and recalculate routes.

Correct Answer: C Section: (none) Explanation

Explanation/Reference:

Explanation:

Split horizon is used to prevent routing loops in distance vector routing environments. It prevents a router from advertising a network back in the direction of the router from which it was learned. In this sense, route advertisements flow «downstream» (away from the route), but never «upstream» (back towards the advertised route).

Poison reverse describes when a router learns that a network has gone down, and the router sends an update back to the neighbor with an infinite metric. Holddown describes when a router ignores any route advertisements that have a lower metric to a downed route.

Triggered updates describe when a router immediately sends a route update with an infinite metric, as opposed to waiting for its next regularly scheduled routing update.

Link State Advertisements (LSA) are packets that are flooded when a topology change occurs, causing network routers to update their topological databases and recalculate routes.

Objective:

Routing Fundamentals Sub-Objective:

Compare and contrast distance vector and link-state routing protocols

References:

Cisco > Articles > Network Technology > General Networking > Dynamic Routing Protocols

QUESTION 52

Which of the following loop avoidance mechanisms drives the requirement to create subinterfaces for each point-to-point connection in a partially meshed frame relay network?

  1. split horizon
  2. poison reverse
  3. maximum hop count
  4. feasible successor

Correct Answer: A Section: (none) Explanation

Explanation/Reference:

Explanation:

Split horizon is the loop avoidance mechanism that drives the requirement to create sub interfaces for each point-to-point connection in a partially meshed frame relay network. Frame relay is a non-broadcast multi-access (NBMA) network and obeys the rules of split horizon. This mechanism prohibits a routing protocol from sending updates out the same physical interface on which it was received. When the same physical interface is used to host multiple frame relay connections, this will prevent an update arriving from remote network A on the physical interface from being sent out the same interface to remote network B.

By creating a subinterface for each frame relay connection and assigning IP addresses to the subinterfaces rather than the physical interface, and by placing the subinterfaces into different subnets, split horizon will not see the «virtual» interfaces as the same interface and will allow these routing updates to be sent back out the same physical interface on which they arrived. It is important to map each subnet (or subinterface) to a remote Data Link Connection Identifier (DLCI) so that traffic to a remote network can be sent out the correct subinterface.

To summarize this discussion:

Subinterfaces solve the NBMA split horizon issues. There should be one IP subnet mapped to each DLCI

Poison reverse is not the mechanism driving the requirement to create subinterfaces for each point-to-point connection in a partially meshed frame relay network. This mechanism requires a router to send an unreachable metric to the interface on which a network was discovered when it is learned from another interface that the network is no longer available.

Maximum hop count is not the mechanism driving the requirement to create sub interfaces for each point-to-point connection in a partially meshed frame relay network. Each routing protocol has a maximum hop count, which is the maximum number of hops allowed to a remote network before the network is considered «unreachable».

Feasible successor is not the mechanism driving the requirement to create sub interfaces for each point-to-point connection in a partially meshed frame relay network. This is a concept unique to EIGRP that represents a secondary route to a network that is considered the «best» route of possible backup routes.

Objective:

LAN Switching Fundamentals Sub-Objective:

Configure and verify Layer 2 protocols

References:

Cisco>Home>Support>Technology Support>IP>IP Routing>Technology Information>technology Whitepaper>EIGRP> Split Horizon and Poison Reverse

QUESTION 53

How is load balancing achieved when implementing HSRP?

  1. By configuring multiple gateways on the routers
  2. By using multiple HSRP groups
  3. By configuring the same priority on all HSRP group members
  4. By configuring multiple virtual router addresses

Correct Answer: B Section: (none) Explanation

Explanation/Reference:

Explanation:

When implementing Hot Standby Router Protocol (HSRP), load balancing is achieved by using multiple HSRP groups. Routers configured for HSRP can belong to multiple groups and multiple VLANs. By configuring one group to be active for Router A and standby for Router B, and the second group to be active for Router B and standby for Router A, both routers A and B can be used to pass traffic, as opposed to one sitting idle.

Load balancing cannot be achieved by configuring multiple gateways on the routers. The routers have one IP address. Each group will have a virtual IP address. In the configuration below, line 4 configures the virtual IP address, and is therefore the address that clients will use as their gateway:

interface fastethernet 0/1 no switchport

ip address 192.168.5.5 255.2555.255.0

standby 1 ip 192.168.5.10

Load balancing cannot be achieved by configuring the same priority on all HSRP group members. If that were done, one of the routers would become active and the others would remain inactive standbys. The active router will be the one with the highest IP address.

Load balancing cannot be achieved by configuring multiple virtual router addresses. Each HSRP group can only have one virtual address. Objective:

Infrastructure Services Sub-Objective:

Configure, verify, and troubleshoot basic HSRP

References:

Internetworking Case Studies > Using HSRP for Fault-Tolerant IP Routing

QUESTION 54

Which Cisco IOS command would produce the preceding menu-based prompt for additional information? A. tracert 10.10.10.1

B. traceroute 12.1.10.2

C. ping 10.10.10.1

D. ping

Correct Answer: D Section: (none) Explanation

Explanation/Reference:

Explanation:

This menu-based prompt for additional information shown would be generated by the Cisco IOS ping command when issued without a target IP address. This is also known as issuing an extended ping. This command can be issued on the router to test connectivity between two remote routers. To execute an extended ping, enter the ping command from the privileged EXEC command line without specifying the target IP address. It takes the command into configuration mode, where various parameters, including the destination and target IP addresses, can be defined.

Note: You can only perform an extended ping at the privileged EXEC command line, while the normal ping works in both user EXEC mode and privileged EXEC mode.

The tracert command is incorrect because the tracert command is used by Microsoft Windows operating systems, not Cisco devices. This command cannot be run via the Cisco IOS command line interface. However, Microsoft’s tracert utility is similar to Cisco’s traceroute utility, which is to test the connectivity or «reachability» of a network device or host. The tracert command uses Internet Control Message Protocol (ICMP) to list all of the ‘hops» or routers traversed to a destination.

The traceroute command is incorrect because this command uses Internet Control Message Protocol (ICMP) to list all of the ‘hops» or routers traversed to a

destination. It is also used to find routing loops or errors within a network.

The ping 10.10.10.1 command is incorrect because you when you issue this command you will either receive a reply from the destination or a destination unreachable message. It will not prompt for additional information as shown

Objective:

Routing Fundamentals Sub-Objective:

Configure, verify, and troubleshoot IPv4 and IPv6 static routing

References:

Cisco > Cisco IOS Command Fundamentals Reference, Release 12.4 > ping

Cisco > Tech Notes > Using the Extended ping and Extended traceroute Commands > Document ID: 13730 > The Extended ping Command Cisco Documentation > Internetwork Troubleshooting Handbook > Troubleshooting TCP/IP

QUESTION 55

On a Cisco 2950 switch, which status LED and color combination indicates a Power On Self-Test (POST) failure?

  1. system LED: no color
  2. system LED: solid red
  3. system LED: solid amber
  4. stat LED: no color
  5. stat LED: green

Correct Answer: C Section: (none) Explanation

Explanation/Reference:

Explanation:

A POST failure is indicated by a solid amber color on the system LED. The switch automatically runs POST which is a series of self-tests to verify proper functioning, after the power is connected. The system LED is off (no color) at the time that POST begins. The LED will turn green if POST is successful, or it will turn amber if POST fails.

The system LED will not be colorless. The system LED will show no color at the beginning of the POST cycle, not after a POST failure. The system LED will not be solid red after a POST failure. Cisco LEDs do not have a red color mode.

The Stat LED indicates the status of each port. If it is amber there is a signal but the port is not forwarding, either because of an address violation or it has been disabled. If it is colorless, there is no signal. In this case:

Ensure the switch has power

Ensure the proper cable type is in use (for a switch to switch connection use a crossover cable: for a switch to host and or switch to router connection use a straight through)

Ensure a good connection by reseating all cables

If it is green, the port has a signal and is functional. Green means:

Layer 1 media is functioning between the switch and the device on the other end of the cable

Layer 2 communication has been established between the switch and the device on the other end of the cable

Objective:

LAN Switching Fundamentals Sub-Objective:

Configure, verify, and troubleshoot interswitch connectivity References:

QUESTION 56

Which of the following is NOT an advantage of static routes over dynamic routing protocols?

  1. Routing protocol overhead is not generated by the router.
  2. Bandwidth is not consumed by route advertisements between network devices.
  3. Static routes are easier to configure and troubleshoot than dynamic routing protocols.
  4. Static route configuration is more fault tolerant than dynamic routing protocols.

Correct Answer: D Section: (none) Explanation

Explanation/Reference:

Explanation:

Static route configuration is NOT more fault tolerant than dynamic routing protocols. The following lists the true advantages of static routes over dynamic routing protocols:

Routing protocol overhead is not generated by the router.

Bandwidth is not consumed by route advertisements between network devices. Static routes are easier to configure and troubleshoot than dynamic routing protocols. Router resources are more efficiently used.

Network security is increased by using static routes.

The following are disadvantages of static routes:

Static routes are not recommended for large networks because static routes are manually configured on the router. Therefore, maintaining routes in a timely manner is nearly impossible.

Static route configuration is not fault tolerant without configuring multiple static routes to each network with varying administrative distances.

All other options are incorrect because these are the advantages of static routes over dynamic routing protocols. Objective:

Routing Fundamentals Sub-Objective:

Compare and contrast static routing and dynamic routing

References:

Cisco Documentation > Internetworking Technology Handbook > Routing Basics

QUESTION 57

Which command would be used to establish static translation between an inside local address 192.168.144.25 and an inside global address 202.56.63.102?

  1. router(config)#ip nat inside source static 192.168.144.25 202.56.63.102
  2. router(config)#ip source nat inside static local-ip 192.168.144.25 global-ip 202.56.63.102
  3. router(config)#ip nat static inside source 192.168.144.25 202.56.63.102
  4. router(config)#ip nat inside static source 192.168.144.25 202.56.63.102

Correct Answer: A Section: (none) Explanation

Explanation/Reference:

Explanation:

To establish a static translation between an inside local address 192.168.144.25 and an inside global address 202.56.63.102, you would use the ip nat inside source static 192.168.144.25 202.56.63.102 command executed in global configuration mode. The correct format of the command is:

ip nat inside source static local-ip global-ip

This static configuration can be removed by entering the global no ip nat inside source static command.

Simply executing the ip nat inside source command will not result in NAT functioning. The NAT process also has to be applied correctly to the inside and outside interfaces. For example, if, in this scenario the Fa0/0 interface hosted the LAN and the S0/0 interface connected to the Internet the following commands would complete the configuration of static NAT.

Router(config)#interface F0/0 Router(config-if)#ip nat inside Router(config-if)#exit Router(config)#interface S0/0 Router(config-if)#ip nat outside

The other options are incorrect because they are not valid Cisco IOS configuration commands. They all contain syntax errors. Objective:

Infrastructure Services Sub-Objective:

Configure, verify, and troubleshoot inside source NAT References:

QUESTION 58

Which WAN switching technology is used by Asynchronous Transfer Mode (ATM)?

  1. cell-switching
  2. virtual switching
  3. circuit-switching
  4. packet switching

Correct Answer: A Section: (none) Explanation

Explanation/Reference:

Explanation:

Cell switching is used by Asynchronous Transfer Mode (ATM). ATM is an International Telecommunication Union-Telecommunications (ITU-T) standard for transmission of data, voice, or video traffic using a fixed size frame of 53 bytes, known as cells. Out of these 53 bytes, the initial five bytes are header information and the remaining 48 bytes are the payload.

The term virtual switching is incorrect because it is not a valid WAN switching technology.

Circuit switching dynamically establishes a virtual connection between a source and destination. The virtual connection cannot be used by other callers unless the

circuit is released. Circuit switching is the most common technique used with the Public Switched Telephone Network (PSTN) to make phone calls. The dedicated circuit is temporarily established for the duration of the call between caller and receiver. Once the caller or receiver hangs up the phone, the circuit is released and is made available to other users.

Packet switching is also used for data transfer but not in an ATM network. With packet switching, the data is broken into labeled packets and is transmitted using packet-switching networks. The Internet and LAN communications use packet switching.

Objective:

WAN Technologies Sub-Objective:

Describe WAN access connectivity options

References:

Cisco > Internetworking Technology Handbook > Asynchronous Transfer Mode (ATM) Switching

QUESTION 59

Examine the diagram below and assume that routing is configured properly.

Why is Host A unable to ping Host B?

  1. The IP address of Switch A is incorrect
  2. The gateway address of Host B is incorrect
  3. The IP address of Host A is incorrect
  4. The Fa0/2 and Fa0/1 interfaces on R1 and R2 are not in the same subnet

Correct Answer: C Section: (none) Explanation

Explanation/Reference:

Explanation:

The IP address of Host A is incorrect. The Fa0/1 interface on R1 (Host A’s default gateway) is in the 192.168.1.64/27 network, and Host A’s IP address is in the 192.168.1.32/27 network. With a 27-bit mask against the 192.168.1.0 classful network, the resulting subnets are:

192.168.1.0

192.168.1.32

192.168.1.64

192.168.1.92

And so it would continue, increasing the fourth octet in intervals of 32. By only going this far we can see that they are in different subnets.

The IP address of Switch A is correct for its subnet because it needs to be in the same subnet as the Fa0/1 interface on R1. Even if it were incorrect or missing altogether it would have no impact on Host A. Switches merely switch frames based on MAC addresses and only need an IP address for management purposes.

The gateway address of Host B is correct. It is in the same subnet (15.0.0.0/8) with the Fa0/2 interface on R2, its gateway.

The Fa0/2 and Fa0/1 interfaces on R1 and R2 are in the same subnet. Using a 25-bit mask against the 192.18.5.0/24 classful network yields the following subnets: 192.18.5.0

192.168.5.128

Both router interfaces in question are in the 192.18.5.0 subnet. Objective:

Network Fundamentals Sub-Objective:

Configure, verify, and troubleshoot IPv4 addressing and subnetting References:

Cisco > Support > IP Routing > Design TechNotes > Document ID: 13788 > IP Addressing and Subnetting for New Users

QUESTION 60

R1 and R2 are connected as shown in the diagram and are configured as shown in output in the partial output of the show run command.

The command ping R2 fails when executed from R1. What command(s) would allow R1 to ping R2 by name?

  1. R1(config)#int S1

R1(config-if)#no ip address 192.168.5.5

R1(config-if)# ip address 192.168.5.9 255.255.255.252

  1. R1(config)#no ip host R1

R1(config)# ip host R2 192.168.5.6 255.255.255.252

  1. R1(config)#no hostname R2 R1(config)# hostname R1
  2. R2(config)#int S1

R1(config-if)#no ip address 192.168.5.5

R1(config-if)# ip address 192.168.5.9 255.255.255.0

Correct Answer: B Section: (none) Explanation

Explanation/Reference:

Explanation:

Both routers have been configured with the ip host command. This command creates a name to IP address mapping, thereby enabling the pinging of the device by address. On R1, the mapping is incorrect and needs to be corrected. Currently it is configured as ip host R1 192.168.5.6. It is currently mapping its own name to the IP address of R2.

To fix the problem, you should remove the incorrect IP address mapping and create the correct mapping for R2, as follows:

R1(config)#no ip host R1

R1(config)# ip host R2 192.168.5.6 255.255.255.252

Once this is done, the ping on R2 will succeed.

The IP address of the S1 interface on R1 does not need to be changed to 192.168.5.9 /30. In fact, if that is done the S1 interface on R1 and the S1 interface in R2 will no longer be in the same network. With a 30-bit mask configured, the network they are currently in extends from 192.168.5.4 — 192.168.5.7. They are currently set to the two usable addresses in that network, 192.168.5.5 and 192.168.5.6.

The hostnames of the two routers do need to be set correctly using the hostname command for the ping to function, but they are correct now and do not need to be changed.

The subnet mask of the S1 interface on R2 does not need to be changed to 255.255.255.0. The mask needs to match that of R1, which is 255.255.255.252. Objective:

Infrastructure Services Sub-Objective:

Troubleshoot client connectivity issues involving DNS References:

QUESTION 61

Which three statements are TRUE regarding Network Address Translation (NAT)? (Choose three.)

  1. It connects different Internet Service Providers (ISPs).
  2. It can act as an address translator between the Internet and a local network.
  3. It conserves IP addresses.
  4. It creates additional IP addresses for the local network.
  5. It helps the local network connect to the Internet using unregistered IP addresses.

Correct Answer: BCE Section: (none) Explanation

Explanation/Reference:

Explanation:

NAT can act as an address translator between the Internet and the local network, conserve Internet Protocol (IP) addresses, and help the local network connect to the Internet using unregistered IP addresses.

The following statements are also TRUE regarding NAT:

It can be used to present a single address for the entire network to the outside world when used in dynamic mode. It enhances network security by not disclosing the internal network addresses to the outside world.

It is not true that NAT connects different Internet Service Providers (ISPs). A gateway is used to connect different ISPs.

It is not true that NAT creates additional IP addresses for the local network. It only enables the use of unregistered addresses on the local area network. Objective:

Infrastructure Services Sub-Objective:

Configure, verify, and troubleshoot inside source NAT References:

QUESTION 62

What is the default sequence in which a router searches for the Internetwork Operating System (IOS) image upon power on?

  1. TFTP, Flash, ROM
  2. ROM, Flash, TFTP
  3. Flash, TFTP, ROM
  4. Flash, TFTP, NVRAM
  5. NVRAM, Flash, TFTP

Correct Answer: C Section: (none) Explanation

Explanation/Reference:

Explanation:

The default sequence in which a router searches for the IOS image is in Flash memory, on a Trivial File Transfer Protocol (TFTP) server, and in read-only memory (ROM). The router will first search for the IOS image in the Flash memory. If there is no image in the Flash, the router will try to contact a TFTP server. If the router cannot find the IOS image on the TFTP server, it will load a limited version from the ROM.

The sequence that begins with TFTP and the sequence that begins with ROM are both incorrect sequences because the router will begin searching for the IOS image in Flash memory.

The sequences that include Non-volatile random access memory (NVRAM) are both incorrect because a router does not store the IOS image in NVRAM. The startup configuration is stored in NVRAM.

Objective:

Infrastructure Management Sub-Objective:

Perform device maintenance

References:

Cisco > Cisco IOS Configuration Fundamentals Configuration Guide, Release 12.4 > Part 9: Loading and Maintaining System Images > Specifying the Startup System Image in the Configuration File

QUESTION 63

Which switch port will be in a blocking state? (Click the Exhibit(s) button to view the switch port diagram.)

  1. SwitchA Fa0/1
  2. SwitchA Fa0/2
  3. SwitchB Fa0/1
  4. SwitchB Fa0/2

Correct Answer: D Section: (none) Explanation

Explanation/Reference:

Explanation:

SwitchB will be forwarding on F0/1, and blocking on F0/2.

SwitchA will become the STP root bridge due to its lower MAC address. All ports on the root bridge will become designated ports in a forwarding state. SwitchB has redundant connectivity to the root bridge, and must block one of its interfaces to prevent a switching loop. STP will use its operations to determine which of the redundant interfaces on SwitchB to block to prevent a switching loop

Both interfaces are the same speed (FastEthernet), and thus their cost to the root is the same.

Finally, the interface with the lowest number will become the forwarding port. F0/1 has a lower port number than F0/2, so F0/1 becomes a forwarding port, and F0/2 becomes a blocking port.

Note: Unlike STP, Rapid Spanning Tree Protocol (RSTP) uses the term «discarding» for a switch port that is not forwarding frames. Objective:

LAN Switching Fundamentals Sub-Objective:

Describe and verify switching concepts

References:

Cisco > Support > LAN Switching > Spanning Tree Protocol > Technology White Paper > Understanding Rapid Spanning Tree Protocol (802.1w) > Document ID: 24062

QUESTION 64

Which type of IP address is a registered IP address assigned by the Internet Service Provider (ISP), and represents one or more inside local IP addresses externally?

  1. Inside local address
  2. Outside local address
  3. Inside global address
  4. Outside global address

Correct Answer: C Section: (none) Explanation

Explanation/Reference:

Explanation:

An inside global address is a registered IP address assigned by the ISP that represents internal local IP addresses externally.

An inside local address is an IP address (usually private) assigned to a host on the internal network. The inside local address is usually not assigned by the service provider, nor used to represent one or more inside local IP addresses externally

An outside local address is the IP address of an outside host as it appears to the internal network. It is not used to represent one or more inside local IP addresses externally

An outside global address is the IP address assigned to a host on the external network by the host owner. The address is allocated from a globally routable address space. It is not used to represent one or more inside local IP addresses externally

Objective:

Infrastructure Services Sub-Objective:

Configure, verify, and troubleshoot inside source NAT

References:

Cisco > Support > Technology Support > IP > IP Addressing Services > Design > Design TechNotes > NAT: Local and Global Definitions Cisco > Articles > Network Technology > General Networking > Network Address Translation

QUESTION 65

You are the switch administrator for InterConn. The network is physically wired as shown in the diagram. You are planning the configuration of STP. The majority of network traffic runs between the hosts and servers within each VLAN.

You would like to designate the root bridges for VLANS 10 and 20. Which switches should you designate as the root bridges?

  1. Switch A for VLAN 10 and Switch E for VLAN 20
  2. Switch A for VLAN 10 and Switch B for VLAN 20
  3. Switch A for VLAN 10 and Switch C for VLAN 20
  4. Switch D for VLAN 10 and Switch B for VLAN 20
  5. Switch E for VLAN 10 and Switch A for VLAN 20
  6. Switch B for VLAN 10 and Switch E for VLAN 20

Correct Answer: B Section: (none) Explanation

Explanation/Reference:

Explanation:

You should designate Switch A for VLAN 10 and Switch B for VLAN 20. The STP root bridge for a particular VLAN should be placed as close as possible to the center of the VLAN. If the majority of network traffic is between the hosts and servers within each VLAN, and the servers are grouped into a server farm, then the switch that all hosts will be sending their data to is the ideal choice for the STP root. Cisco’s default implementation of STP is called Per-VLAN Spanning Tree (or

PVST), which allows individual tuning of the spanning tree within each VLAN. Switch A can be configured as the root bridge for VLAN 10, and Switch B can be configured as the root bridge for VLAN 20, resulting in optimized traffic flow for both.

None of the other switches is in the traffic flow of all data headed towards the VLAN 20 or VLAN 10 server farms, so they would not be good choices for the root bridge for either VLAN. Care should be taken when adding any switch to the network. The addition of an older, slower switch could cause inefficient data paths if the old switch should become the root bridge.

Objective:

LAN Switching Fundamentals Sub-Objective:

Configure, verify, and troubleshoot STP protocols

References:

Cisco > Support > Technology Support > LAN Switching > Spanning Tree Protocol > Configure > Configuration Examples and TechNotes > Understanding and Configuring Spanning Tree Protocol (STP) on Catalyst Switches

QUESTION 66

Which of the following statements are true with regard to the network shown in the exhibit? (Click the Exhibit(s) button.)

  1. there is one broadcast domain and one collision domain
  2. there is one broadcast domain and four collision domains
  3. there are two broadcast domains and two collision domains
  4. there are two broadcast domains and four collision domains
  5. the hosts in VLAN1 could use IP addresses 192.168.5.4/24 and 192.168.5.5/24 and the hosts in VLAN2 could use IP addresses 192.168.6.1/24 and 192.168.6.2/24
  6. the hosts in VLAN2 could use IP addresses 192.168.5.5/24 and 192.168.6.5/24

Correct Answer: DE Section: (none) Explanation

Explanation/Reference:

Explanation:

There are two broadcast domains and four collision domains in the network shown in exhibit. A Virtual LAN (VLAN) is a group of networking devices in the same broadcast domain. A broadcast domain is a group of devices such that when one device in the group sends a broadcast, all the other devices in the group will receive that broadcast. Because there are two VLANs shown in the exhibit, VLAN1 and VLAN2, there are two broadcast domains. A switch will not forward broadcast frames between VLANs.

A collision domain is a domain where two or more devices in the domain could cause a collision by sending frames at the same time. Each switch port is a separate collision domain. Because there are four switch ports in the exhibit, there are four collision domains.

The hosts in VLAN1 could use IP addresses 192.168.5.4/24 and 192.168.5.5/24 and the hosts in VLAN2 could use IP addresses 192.168.6.1/24 and 192.168.6.2/24. Hosts in different VLANs must have IP addresses that are in different subnets.

The other options that offer IP address plans are incorrect because they either place hosts from different VLANs in the same subnet, or place hosts in the same VLAN in different subnets.

Objective:

LAN Switching Fundamentals Sub-Objective:

Configure, verify, and troubleshoot VLANs (normal/extended range) spanning multiple switches

References:

Cisco > Support>Technology Support > LAN Switching > Layer-Three-Switching and Forwarding > Configure > Configuration Examples and TechNotes > How To Configure InterVLAN Routing on Layer 3 Switches

QUESTION 67

Which command was used to create the following configuration?

A. Router(config-router)# network 192.168.1.0 0.0.0.15

B. Router(config-router)# network 192.168.1.0 255.255.255.0

C. Router(config-router)# network 192.168.1.80 Router(config-router)# network 192.168.1.128

D. Router(config-router)# network 192.168.1.0

Correct Answer: D Section: (none) Explanation

Explanation/Reference:

Explanation:

The network 192.168.1.0 command instructs the router to activate EIGRP on every interface that belongs to the class C network 192.168.1.0. The exhibit indicates that the router is running EIGRP on two subnets of 192.168.1.0 (192.168.1.80/28 and 192.168.1.128/28). Since both of these are subnets of the same class C network number, only the class C address needs to be referenced with a network statement.

All interfaces that will participate in EIGRP must be specified with a network command that specifying the network of which the interface is a member. Failure to do so will result in neighbor relationships not forming. In the example below, Router A and Router B are directly connected, but not forming a neighbor relationship. The network they share is the 192.168.5.0/24 network. The output of the show run command for both routers reveals that Router B does not have EIGRP running on the 192.168.5.0 network.

The network 192.168.1.0 0.0.0.15 command is incorrect because only the class C network number (192.168.1.0) needs to be referenced to enable EIGRP on all

subnets. It is actually valid to include an inverse mask with EIGRP network statements, but it is unnecessary in this case, and the network/mask provided does not match either of the routed networks.

The network 192.168.1.0 255.255.255.0 command is incorrect because the mask is unnecessary in this case, and if masks are included, they must be expressed inversely (0.0.0.255).

It is unnecessary to configure two network commands in this example, as both networks are subnets of the same class C network (192.168.1.0), and a single network command can enable EIGRP on both. Additionally, if specific subnets are referenced in network commands, it is necessary to include an inverse mask after them, or EIGRP will automatically summarize the command to the classful boundary.

Objective:

Routing Fundamentals Sub-Objective:

Configure, verify, and troubleshoot EIGRP for IPv4 (excluding authentication, filtering, manual summarization, redistribution, stub)

References:

Cisco > Cisco IOS IP Routing Protocols Configuration Guide, Release 12.4T > Part 3: EIGRP > Configuring EIGR

QUESTION 68

Which of the following represents the correct method of assigning an IP address and default gateway to a switch?

  1. Switch(config)# interface vlan1

Switch(config-if)# ip address 10.0.0.1 255.0.0.0

Switch(config-if)# default-gateway 10.0.0.254

  1. Switch(config)# ip default-gateway 10.0.0.254 Switch(config)# interface vlan1

Switch(config-if)# ip address 10.0.0.1 255.0.0.0

  1. Switch(config)# ip address 10.0.0.1 255.0.0.0 Switch(config)# default-gateway 10.0.0.254
  2. Switch(config)# ip address 10.0.0.1 255.0.0.0 Switch(config)# interface vlan1 Switch(config)# ip default-gateway 10.0.0.254

Correct Answer: B Section: (none) Explanation

Explanation/Reference:

Explanation:

IP addresses are assigned to switches by assigning the address to VLAN 1 using the ip address command, while the default gateway is configured in global configuration mode using the ip default-gateway command. A default gateway is assigned to a Layer 2 switch using the following command syntax, where h.h.h.h is

the IP address of the default gateway:

Switch(config)# ip default-gateway h.h.h.h

An IP address is assigned to a Layer 2 switch using the following command syntax, where h.h.h.h is the IP address and m.m.m.m is the subnet mask:

Switch(config)# interface vlan1

Switch(config-if)# ip address h.h.h.h m.m.m.m

Configuring an IP address on a switch is usually accompanied by adding a default gateway as well. Switches do not require an IP address to perform their function on the network. IP addresses are added so that an administrator can make a Telnet connection to the switch to manage the switch. If this Telnet access does not occur on the same local subnet with the switch, which is unlikely, or if the administrator is trying to Telnet to the switch using a host that resides a VLAN other VLAN1 (the management VLAN) the absence of a gateway address will render the switch incapable of answering Telnet connection attempts. Therefore, a gateway address is usually required on the switch to make a telnet connection.

The following command set is incorrect because the command setting the default gateway must be executed in global configuration mode, not in configuration mode, for VLAN1:

Switch(config)# interface vlan1

Switch(config-if)# ip address 10.0.0.1 255.0.0.0

Switch(config-if)# default-gateway 10.0.0.254

The following command set is incorrect because the IP address must be configured in configuration mode for VLAN1, not global configuration mode:

Switch(config)# ip address 10.0.0.1 255.0.0.0

Switch(config)# default-gateway 10.0.0.254

The following command set is incorrect because an IP address must be configured in configuration mode for VLAN1. Also, if you executed the command interface vlan1, the prompt would change to Switch(config-if)#. Once it did, that would be an incorrect mode for entering the default gateway.

Switch(config)# ip address 10.0.0.1 255.0.0.0 Switch(config)# interface vlan1 Switch(config)# ip default-gateway 10.0.0.254

Objective:

Infrastructure Management Sub-Objective:

Configure and verify device management References:

QUESTION 69

Which statement best describes a converged network?

  1. a network with real-time applications
  2. a network with a mix of voice, video, and data traffic
  3. a network with a mix of voice and video traffic
  4. a network with mix of data and video traffic

Correct Answer: B Section: (none) Explanation

Explanation/Reference:

Explanation:

A converged network is a combination of voice, video, and data traffic. Network convergence is a migration from maintaining multiple service-specific networks, namely data voice and video, to a single IP-based network. All services are delivered on the same network, reducing infrastructure costs. Despite the benefits that network convergence provides, it is highly susceptible to network delays, especially for real-time traffic.

Converged networks frequently face the following problems:

Bandwidth: As all the voice and video networks are combined into one universal converged network, bandwidth capacity becomes a priority. Packet loss: When links become congested, packets will be dropped. Voice and video traffic are intolerant of dropped packets.

Delay: Delay represents the time it takes for packets to traverse the network and reach their destinations. While some delay is expected, delay increases when links are over-subscribed.

Voice and video traffic are intolerant of high or variable delay. A packet that arrives late is no better than a packet that does not arrive. Delays can be variable and fixed.

Fixed delays are constant and mostly induced by the computing software of the hardware devices, such as processing delay and packetization delay. Variable delays, known as jitter, cause problems for voice and video.

Objective:

Network Fundamentals Sub-Objective:

Compare and contrast network topologies

References:

Cisco Documentation > Internetworking Technology Handbook > Multiservice Access Technologies

QUESTION 70

The output of the show ip route command is given:

Router# show ip route

Gateway of last resort is 10.119.254.240 to network 10.140.0.0 O 172.16.0.0 [110/5] via 10.19.24.6, 0:01:00, Ethernet2

B 172.17.12.0 [200/128] via 10.19.24.24, 0:02:22, Ethernet2

O 172.71.13.0 [110/5] via 10.19.24.6, 0:00:59, Ethernet2

O 10.13.0.0 [110/5] via 10.19.24.6, 0:00:59, Ethernet2

What does the value 110 in the output represent?

  1. The administrative distance of the information source
  2. The metric to the route
  3. The type of route
  4. The port number of the remote router

Correct Answer: A Section: (none) Explanation

Explanation/Reference:

Explanation:

The value 110 in the output represents the administrative distance (AD) of the information source. Administrative distance is used by Cisco routers to select the most trustworthy source of routing information for a particular route. Every routing protocol has a default administrative distance, and if more than one routing protocol is providing route information about a route, the protocol with the lowest AD will be selected to populate the routing table. The following table shows the AD values for different routing protocols:

The following is the sample output for the show ip route command:

Router# show ip route

Gateway of last resort is 10.119.254.240 to network 10.140.0.0 O 172.16.0.0 [110/5] via 10.19.24.6, 0:01:00, Ethernet2

B 172.17.12.0 [200/128] via 10.19.24.24, 0:02:22, Ethernet2

O 172.71.13.0 [110/5] via 10.19.24.6, 0:00:59, Ethernet2

O 10.13.0.0 [110/5] via 10.19.24.6, 0:00:59, Ethernet2

The following are the fields in the output:

O: Indicates that the route was discovered using Open Shortest Path First (OSPF). B: Indicates that the route was discovered using Border Gateway Protocol (BGP). 172.16.0.0: Indicates the address of the remote network.

110: Indicates the administrative distance of the route. 128: Indicates the metric for the route.

Via 10.19.24.6: Specifies the address of the next router in the remote network. 0:02:22: Indicates the last time the route was updated.

The metric for the route is also called the cost. In the case of the OSPF routes above, the cost is 5.

The administrative distance for any particular protocol can be changed if you would like to use a routing protocol that is normally not the preferred provider. For example, if you prefer that RIP routes be installed in the routing table rather than OSPF routes, you could change the administrative distance of RIP to a lower value than OSPF (110), as shown below.

Router(config)# router rip Router(config)# distance 100

All the other options are incorrect because they do not represent the administrative distance. Objective:

Routing Fundamentals Sub-Objective:

Interpret the components of routing table

References:

Cisco > Support > IP > IP Routing > Design > Design TechNotes > What Is Administrative Distance? > Document ID: 15986

QUESTION 71

In which of the following networks does the address 192.168.54.23/27 reside?

A. 192.168.54.0

B. 192.168.54.8

C. 192.168.54.4

D. 192.168.54.16

Correct Answer: A Section: (none) Explanation

Explanation/Reference:

Explanation:

When a class C address such as 192.168.54.0 is subnetted with a /27 mask, the subnet mask in dotted decimal format is 255.255.255.224. This means that the interval between the network IDs of the resulting subnets is 32. The resulting network IDs are as follows:

192.168.54.0

192.168.54.32

192.168.54.64

192.168.54.92 and so on.

Therefore, the address 192.168.54.23 resides in the 192.168.54.0 subnet. The address 192.168.54.0 is called a network ID or, alternately, a subnet address. It represents the subnet as a group and will be used in the routing tables to represent and locate the subnet.

Neither the first address (192.168.54.0, the network ID) nor the last address (192.168.54.31, the broadcast address) in any resulting subnet can be used. Therefore, the addresses in this range are 192.168.54.1 through 192.168.54.30, which includes the 192.168.54.23 address.

192.168.54.8 would only be a network ID if the mask were /29, which would result in an interval of 8 between network IDs. However, even if a /29 mask were used, the 192.168.54.23 address would not fall in its range. The address range for a /29 mask would be 192.168.54.9 through 192.168.54.14.

Similarly, 192.168.54.4 would only be a network ID for a /30 mask, which would result in an interval of 4 between network IDs. But even if a /30 mask were used, the 192.168.54.23 address would not fall in its range. The address range for a /30 mask would be 192.168.54.5 through 192.168.54.6.

192.168.54.16 could be a network ID if the mask were /28, /29 or /30, but not with a /27 mask. Objective:

Network Fundamentals Sub-Objective:

Apply troubleshooting methodologies to resolve problems

References:

Cisco > Support > IP Routing > Design TechNotes > Document ID: 13788 > IP Addressing and Subnetting for New Users

QUESTION 72

What is the primary benefit of the Virtual Local Area Network (VLAN) Trunking Protocol (VTP)?

  1. broadcast control
  2. frame tagging
  3. inter-VLAN routing
  4. consistent VLAN configuration across switches in a domain

Correct Answer: D Section: (none) Explanation

Explanation/Reference:

Explanation:

VTP manages configured VLANs across a switched network and maintains consistency of VLAN information throughout a VTP domain. When an administrator adds, deletes, or renames VLANs, VTP propagates this information to all other switches in the VTP domain. This makes the process of VLAN changes a plug-and- play activity. This protocol was developed by, and remains proprietary to Cisco Systems.

Broadcast control is not the primary benefit of VTP. Broadcast control is achieved by using VLANs. VLANs segment the network into logical broadcast domains. This helps in the reduction of unnecessary traffic over the network and optimizes the available bandwidth use. VTP pruning helps reduce broadcast and unknown unicast over VLAN trunk links. However, this is not the primary benefit of VTP.

Frame tagging is required for VLAN identification as frames traverse trunk links in a switch fabric. Inter-Switch Link (ISL) and IEEE 802.1q are the two methods of frame tagging available on Cisco devices. ISL is proprietary to Cisco, whereas IEEE 802.1q is a standard method. VTP is not a frame tagging method.

Inter-VLAN routing is achieved by an Open Systems Interconnect (OSI) Layer 3 device (Router). Inter-VLAN routing is not a benefit of VTP.

Objective:

LAN Switching Fundamentals Sub-Objective:

Configure, verify, and troubleshoot VLANs (normal/extended range) spanning multiple switches

References:

Cisco > Support > LAN Switching > Virtual LANS / VLAN Trunking Protocol (VLANS/VTP) > Configure > Configuration Examples and Technotes > Configuring VLAN Trunk Protocol (VTP) > Document ID: 98154

Cisco > Catalyst 4500 Series Switch Cisco IOS Software Configuration Guide, 12.2(25) > Understanding and Configuring VLANs, VTP, and VMPS

QUESTION 73

You are the network administrator for your company and have configured Cisco Discovery Protocol (CDP) in your network. You recently noticed that when devices send large numbers of CDP neighbor announcements, some devices are crashing. You decide to disable CDP on the router.

Which command should you use to achieve the objective?

  1. no cdp run
  2. set cdp disable
  3. no cdp enable
  4. no cdp advertise-v2

Correct Answer: A Section: (none) Explanation

Explanation/Reference:

Explanation:

You should use the no cdp run command to disable CDP on the router. Due to a known vulnerability regarding the handling of CDP by Cisco routers and switches when devices send large numbers of CDP neighbor announcements, some devices can crash or cause abnormal system behavior. To overcome this problem, you can disable CDP for the entire router by using the no cdp run command.

You cannot use the set cdp disable command to disable CDP on the router. This command disables CDP on an entire Catalyst switch. You cannot use the no cdp enable command to disable CDP on the router. This command disables CDP on a specific interface.

You cannot use the no cdp advertise-v2 command to disable CDP on the router. This command disables CDPv2 advertisements. Objective:

LAN Switching Fundamentals Sub-Objective:

Configure and verify Layer 2 protocols

References:

Cisco > Support > Using Cisco Discovery Protocol

Cisco > Support > Technology Support > Network Management > Cisco’s Response to the CDP Issue > Document ID: 13621

QUESTION 74

Two catalyst switches on a LAN are connected to each other with redundant links and have Spanning Tree Protocol (STP) disabled. What problem could occur from this configuration?

  1. It may cause broadcast storms.
  2. All ports on both switches may change to a forwarding state.
  3. It may cause a collision storm.
  4. These switches will not forward VTP information.

Correct Answer: A Section: (none) Explanation

Explanation/Reference:

Explanation:

The configuration in the scenario may cause broadcast storms. When there are redundant links between two switches, it is recommended that you enable Spanning Tree Protocol to avoid switching loops or broadcast storms. Loops occur when there is more than one path between two switches. STP allows only one active path at a time, thus preventing loops. A broadcast storm occurs when the network is plagued with constant broadcasts. When the switches have redundant links, the resulting loops would generate more broadcasts, eventually resulting in a complete blockage of available bandwidth that could bring the complete network down.

This situation is referred to as a broadcast storm.

The option stating that all ports on both switches may change to a forwarding state is incorrect. Forwarding is a port state that is available when using STP. When STP is disabled, the switch cannot change the STP states of its ports.

The option stating that the switches will not forward VLAN Trunking Protocol (VTP) information is incorrect. Enabling or disabling STP does not have a direct effect on VTP messages.

The term collision storm is not a valid term. Objective:

LAN Switching Fundamentals Sub-Objective:

Configure, verify, and troubleshoot interswitch connectivity

References:

Cisco > Support > Technology Support > LAN Switching > Ethernet > Design > Troubleshooting LAN Switching Environments > Document ID: 12006 > Spanning Tree Protocol

QUESTION 75

You are advising a client on the options available to connect a small office to an ISP. Which of the following is an advantage of using an ADSL line?

  1. it uses the existing cable TV connection
  2. it uses the existing phone line
  3. you receive a committed information rate (CIR) from the provider
  4. the upload rate is as good as the download rate

Correct Answer: B Section: (none) Explanation

Explanation/Reference:

Explanation:

xDSL lines, including the ADSL variant, use the existing phone line and as such make installing only a matter of hooking up the DSL modem to the line. It does not use the use the existing cable TV connection. This is a characteristic of using a cable modem rather than ADSL.

You do not receive a committed information rate (CIR) from the provider. CIR is provided with a frame relay connection.

The upload rate is NOT as good as the download rate with asynchronous DSL (ADSL). The download rate is significantly better than the upload rate. Symmetric Digital Subscriber Line (SDSL) is a version of DSL that supplies an equal upload and download rate, but that is not the case with ADSL.

Objective:

WAN Technologies Sub-Objective:

Describe WAN access connectivity options

References:

Cisco Documentation > Internetworking Technology Handbook > Introduction to WAN Technologies > DSL

QUESTION 76

Consider the following diagram:

Which of the following routing protocols could NOT be used with this design?

  1. RIPv1
  2. RIPv2
  3. EIGRP
  4. OSPF

Correct Answer: A Section: (none) Explanation

Explanation/Reference:

Explanation:

The network design displayed has subnets of a major classful network located in opposite directions from the perspective of some of the individual routers. This configuration can be accommodated by any routing protocol that supports Variable Length Subnet masks (VLSM) or the transfer of subnet mask information in routing advertisements.

RIPv1 supports neither of these. RIPv1 will automatically summarize routing advertisements to their classful network (in this case 192.168.1.0/24). This action will cause some of the routers to have routes to the same network with different next hop addresses, which will NOT work.

EIGRP, RIPv2 and OSPF all support VLSM and can be used in the design shown in the scenario. Objective:

Routing Fundamentals

Sub-Objective:

Compare and contrast distance vector and link-state routing protocols

References:

Cisco > Home > Support > Technology Support > IP > IP Routed Protocols > Design > Design TechNotes > Why Don’t IGRP and RIP v1 support VLSM?

QUESTION 77

You have established a console session with R1 and you are attempting to download an IOS image from the TFTP server in the diagram below.

However, you are unable to make the connection to 150.140.6.5. What is the problem?

  1. The IP address of the management station is incorrect
  2. The IP address of the TFTP server is incorrect
  3. The interfaces between R1and R2 are not in the same subnet
  4. The IP address of Switch B is incorrect

Correct Answer: B Section: (none) Explanation

Explanation/Reference:

Explanation:

The IP address of the TFTP server is incorrect. The TFTP server, Switch B and the Fa0/2 interface on R3 should all be in the same subnet. With a 27-bit mask

(255.255.255.224) against the 150.140.0.0 classful network the resulting subnets are:

150.140.0.0

150.140.0.32

150.140.0.64

and so on, incrementing in intervals of 32 in the last octet until it reaches the 150.140.6.0 subnet. 150.140.6.0

150.140.6.32

150.140.6.64

At this point, we can see that Switch B and the router interface are in the 150.140.6.32 subnet, while the TFTP server is in the 150.140.6.0 subnet. The IP address of the TFTP server needs to be in the 150.140.6.33-150.140.6.62 range, while avoiding the addresses already used on R1 and the switch.

The IP address of the management station does not appear to be in any of the networks listed in the diagram, but that doesn’t matter since the connection to the router is through the console cable which does not require a correct IP address.

The Fa0/2 and Fa0/1 interfaces on R1 and R2 are in the same subnet. Using a 25-bit mask against the 192.18.5.0/24 classful network yields the following subnets: 192.18.5.0

192.168.5.128

Both router interfaces in question are in the 192.18.5.0 subnet.

As we have already determined, the IP address of Switch B is correct. Even if it were incorrect or missing altogether, it would have no impact on connecting to the TFTP server. Switches merely switch frames based on MAC addresses and only need an IP address for management purposes.

Objective:

Routing Fundamentals Sub-Objective:

Troubleshoot basic Layer 3 end-to-end connectivity issues

References:

Cisco > Support > IP Routing > Design TechNotes > Document ID: 13788 > IP Addressing and Subnetting for New Users

QUESTION 78

You run the following command: switch# show ip interface brief What information is displayed?

  1. A summary of the IP addresses and subnet mask on the interface
  2. A summary of the IP addresses on the interface and the interface’s status
  3. The IP packet statistics for the interfaces
  4. The IP addresses for the interface and the routing protocol advertising the network

Correct Answer: B Section: (none) Explanation

Explanation/Reference:

Explanation:

The command show ip interface brief displays a summary of the IP address on the interface and the interface’s status. The status shows whether the interface is up. This command is useful when you are connected to a router or switch with which you are not familiar, because it allows you to obtain the state of all interfaces or switch ports.

Sample output of this command is shown below:

This command does not display subnet mask information. You should use other commands, such as show ip interface or show run interface, to verify the subnet mask.

IP statistics about the interface are displayed with the command show ip interface. Adding the brief keyword tells the switch to leave out everything but the state of the interface and its IP address.

To view the routing protocol advertising an interfaces network, you would use the command show ip protocol. Objective:

LAN Switching Fundamentals

Sub-Objective:

Configure, verify, and troubleshoot interswitch connectivity

References:

Cisco > Support > Cisco IOS IP Addressing Services Command Reference > show ip interface

QUESTION 79

Which command can be issued at the following prompt?

Router(config-router)#

  1. show interface
  2. network
  3. interface
  4. ip default-gateway

Correct Answer: B Section: (none) Explanation

Explanation/Reference:

Explanation:

The network command can be issued at the Router(config-router)# prompt, which also indicates that the router is in router configuration mode. The network command is used to configure the network upon which a routing protocol is functioning.

The router configuration mode is accessed by issuing the router command in the global configuration mode along with a parameter indicating the routing protocol to be configured. For example:

R4(config)#router eigrp 1

changes the prompt to:

R4(config-router)#

which then allows you to specify the network as follows:

R4(config-router)#network 192.18.5.0

All other options are incorrect as these commands can be issued only in the global configuration command mode (which would be indicated by the R4(config)# prompt.

Objective:

Infrastructure Management Sub-Objective:

Configure and verify initial device configuration

References:

Cisco > Support > Cisco IOS Software > Using the Command-Line Interface in Cisco IOS Software

QUESTION 80

Which of the following is NOT managed by the cloud provider in an IaaS deployment?

  1. virtualization
  2. servers
  3. storage
  4. operating system

Correct Answer: D Section: (none) Explanation

Explanation/Reference:

Explanation:

Operating systems are not managed by the cloud provider in an Infrastructure as a service (IaaS) deployment. Only storage, virtualization, servers, and networking are the responsibility of the provider. The customer is responsible for the following with IaaS:

Operating systems Data

Applications Middleware Runtime

In a Platform as a Service (PaaS) deployment, the provider is responsible for all except the following, which is the responsibility of the customer: Applications

Data

In Software as a Service (SaaS) deployment, the provider is responsible for everything. Objective:

Network Fundamentals Sub-Objective:

Describe the effects of cloud resources on enterprise network architecture

References:

IaaS, PaaS, SaaS (Explained and Compared)

QUESTION 81

What command produced the following as a part of its output?

1 14.0.0.2 4 msec 4 msec 4 msec

2 63.0.0.3 20 msec 16 msec 16 msec

3 33.0.0.4 16 msec * 16 msec

  1. Ping
  2. Traceroute
  3. Tracert
  4. Extended ping

Correct Answer: B Section: (none) Explanation

Explanation/Reference:

Explanation:

The output displayed is a part of the output from executing the traceroute command. The traceroute command finds the path a packet takes while being transmitted to a remote destination. It is also used to track down routing loops or errors in a network. Each of the following numbered sections represents a router being traversed and the time the packet took to go through the router:

1 14.0.0.2 4 msec 4 msec 4 msec

2 63.0.0.3 20 msec 16 msec 16 msec

3 33.0.0.4 16 msec * 16 msec

The output would not be displayed by the ping command. This command is used to test connectivity to a remote ip address. The output from the ping command is as follows:

router1# ping 10.201.1.11

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.201.1.11, timeout is 2 seconds:

…..

Success rate is 0 percent (0/5)

The ping in this output was unsuccessful, as indicated by the Success rate is 0 percent output.

The output would not be displayed by the tracert command. The tracert command is used by Microsoft Windows operating systems, not the Cisco IOS command line interface. However, the purpose of the tracert command is similar to the Cisco traceroute utility, which is to test the connectivity or «reachability» of a network device or host. The tracert command uses Internet Control Message Protocol (ICMP).

The output would not be displayed by the extended version of the ping command. This command can be issued on the router to test connectivity between two remote routers. A remote execution means that you are not executing the command from either of the two routers you are interested in testing, but from a third router.

To execute an extended ping, enter the ping command from the privileged EXEC command line without specifying the target IP address. The command takes the router into configuration mode, where you can define various parameters, including the destination and target IP addresses. An example is below:

Protocol [ip]:

Target IP address: 10.10.10.1 Repeat count [5]:

Datagram size [100]:

Timeout in seconds [2]:

Extended commands [n]: y

Source address or interface: 12.1.10.2 Type of service [0]:

Set DF bit in IP header? [no]:

Validate reply data? [no]:

Data pattern [0xABCD]:

Loose, Strict, Record, Timestamp, Verbose[none]:

Sweep range of sizes [n]:

Type escape sequence to abort.

Each line is a menu question allowing you to either accept the default setting (in parenthesis) of the ping or apply a different setting. The real value of this command is that you can test connectivity between two remote routers without being physically present at those routers, as would be required with the standard version of the ping command.

Objective:

Routing Fundamentals Sub-Objective:

Troubleshoot basic Layer 3 end-to-end connectivity issues

References:

Cisco > Cisco IOS Command Fundamentals Reference, Release 12.4 > ping

Cisco > Tech Notes > Using the Extended ping and Extended traceroute Commands > Document ID: 13730 > The Extended ping Command

QUESTION 82

In the diagram below, when a packet sent from the PC at 10.0.1.3 to the PC at 10.1.1.3 leaves the Fa0/1 interface of R1, what will be the source and destination IP and MAC addresses?

  1. source IP 10.1.1.2 destination IP 10.1.1.3

Source MAC ad.ad.ad.ad.ad.ad destination MAC ab.ab.ab.ab.ab.ab

  1. source IP 10.1.1.1 destination IP 10.1.1.3

Source MAC ad.dd.dd.dd.dd.dd.dd destination MAC ab.ab.ab.ab.ab.ab

  1. source IP 10.0.1.3 destination IP 10.1.1.3

Source MAC ad.ad.ad.ad.ad.ad destination MAC ae.ae.ae.ae.ae.ae

  1. source IP 10.0.6.3 destination IP 10.1.1.3

Source MAC ad.ad.ad.ad.ad.ad destination MAC ae.ae.ae.ae.ae.ae

Correct Answer: C Section: (none) Explanation

Explanation/Reference:

Explanation:

The source IP address will be 10.0.1.3 and the destination IP address will be 10.1.1.3. The source MAC address will be ad.ad.ad.ad.ad.ad and the destination MAC address will be ae.ae.ae.ae.ae.ae.

The source and destination IP addresses never change as the packet is routed across the network. The MAC address will change each time a router sends the packet to the next router or to the ultimate destination. The switches do not change either set of addresses in the header; they just switch the frame to the correct switch port according to the MAC address table. Therefore, when the packet leaves R1, the source MAC address will be that of R1 and the destination MAC address will be that of the Fa0/0 interface of R2. The IP addresses will be those of the two workstations, 10.0.1.3 and 10.1.1.3.

When the workstation at 10.0.1.3 starts the process, it will first determine that the destination address is in another subnet and will send to its default gateway (10.0.1.2). It will perform an ARP broadcast for the MAC address that goes with 10.0.1.2, and R1 will respond with its MAC address, bb.bb.bb.bb.bb.bb.

After R2 determines the next-hop address to send to 10.0.1.3 by parsing the routing table, it will send the packet to R1 at 10.0.6.2. When R2 receives the packet, R2 will determine that the network 10.0.1.0/24 is directly connected and will perform an ARP broadcast for the MAC address that goes with 10.0.1.3. The workstation at 10.0.1.3 will respond with its MAC address, ab.ab.ab.ab.ab.ab.

Objective:

Routing Fundamentals Sub-Objective:

Describe the routing concepts

References:

Cisco > IOS Technology Handbook > Routing Basics

QUESTION 83

Which are among the valid steps in the process of recovering a password on a Cisco router? (Choose all that apply.)

  1. Restart the router.
  2. Configure the enable secret password.
  3. Enter the router diagnostic mode.
  4. Enter user mode.
  5. Answer the security question to recover the password.

Correct Answer: ABC Section: (none) Explanation

Explanation/Reference:

Explanation:

Three of the steps that should be performed while recovering a password on a Cisco router are to restart the router in ROMMOM mode, enter ROMMON mode (router diagnostic mode) and reset the enable secret password. The complete password recovery process on a Cisco Router is as follows:

Configure the router so that it starts without reading the non-volatile random access memory (NVRAM). This is also referred to as the system test mode, which you enter by changing the configuration register. You must first restart the router and within 60 seconds press Break on the terminal keyboard. Then the router will skip normal reading of the startup configuration file and will go to the ROMMON prompt (shown below this text section). At this command prompt, type confreg 0x2142 to instruct the router to boot to flash memory at the next reboot. When it does, it will ignore the startup configuration file again and will behave as if it had no configuration, as a new router would.

rommon 1> confreg 0x2142

Type reset to reboot the router.

Enter enable mode through the test system mode.

View the existing password (if it can be viewed, it may be encrypted), configure a new password, or delete the configuration.

Configure the router to start by reading the NVRAM, which is done by resetting the configuration register to its normal value. Run these commands:

Router#configure terminal

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

Router(config)#config Router(config)#config-register 0x2102

Restart the router.

You will proceed through user mode but to make any changes you make must be at the global configuration prompt. Finally, there is no way to recover a password by answering a security question.

Objective:

Infrastructure Management Sub-Objective:

Use Cisco IOS tools to troubleshoot and resolve problems

References:

Cisco > Home>Support>Product Support>End-of-Sale and End-of-Life Products>Cisco IOS Software Releases 12.1 Mainline>Troubleshoot and Alerts> Troubleshooting TechNotes> Password Recovery Procedures

QUESTION 84

You are the network administrator for your company. You have implemented VLAN Trunking Protocol (VTP) in your network. However, you have found that VTP is not synchronizing VLAN information.

Which of the following items should be verified to resolve the problem? (Choose three.)

  1. Ensure that switches in the VTP domain are configured with VTP version 1 and version 2.
  2. Ensure that VLANs are active on at least one switch on the VTP domain.
  3. Ensure that all of the ports that interconnect switches are configured as trunks and are trunking properly.
  4. Ensure that the VTP domain name is the same on all switches in the domain.
  5. Ensure that identical passwords are configured on all VTP switches.

Correct Answer: CDE

Section: (none) Explanation

Explanation/Reference:

Explanation:

The following is a list of the steps to take if VTP fails to exchange VLAN information:

Ensure that all of the ports that interconnect switches are configured as trunks and are trunking properly. Ensure that VLANs are active in all the devices.

Ensure that at least one switch is acting as a VTP server in the VTP domain.

Ensure that the VTP domain name is the same for all switches in the domain. The VTP domain name is case-sensitive. Ensure that the VTP password is the same for all switches in the domain.

Ensure that the same VTP version is used by every switch in the domain. VTP version 1 and version 2 are not compatible on switches in the same VTP domain.

You should not ensure that switches are configured with VTP version 1 and version 2 in the domain, because VTP version 1 and version 2 are incompatible. VTP version 1 is the default on all Cisco switches.

You should not ensure that VLANs are active on at least one switch in the VTP domain, because VLANs should be active in all of the devices in a VTP domain. Objective:

LAN Switching Fundamentals Sub-Objective:

Configure, verify, and troubleshoot VLANs (normal/extended range) spanning multiple switches References:

QUESTION 85

Which of the following is NOT a possible component of Enhanced Interior Gateway Routing Protocol’s (EIGRP) composite metric?

  1. Cost
  2. Load
  3. Delay
  4. Bandwidth

Correct Answer: A Section: (none) Explanation

Explanation/Reference:

Explanation:

Cost is not a component of EIGRP’s composite metric. The cost, or efficiency, of a path is used as a metric by the Open Shortest Path First (OSPF) routing protocol.

Enhanced IGRP (EIGRP) is Cisco Systems’ proprietary routing protocol. It can use bandwidth, delay, load, reliability, and maximum transmission unit (MTU) to calculate the metric. Of these five metrics, by default, only minimum bandwidth and delay are used to compute the best path.

The metric for EIGRP can be calculated with this formula:

Metric = [K1 * Bandwidth + (K2 * Bandwidth) / (256-load) + K3*Delay] * [K5 / (reliability + K4)]

The default constant values for Cisco routers are K1 = 1, K3 = 1, and K2 = 0, K4 = 0, K5 = 0. In the default setting, K1 and K3 have non-zero values, and therefore, by default, the metric is dependent on bandwidth and delay.

Objective:

Routing Fundamentals Sub-Objective:

Configure, verify, and troubleshoot EIGRP for IPv4 (excluding authentication, filtering, manual summarization, redistribution, stub)

References:

Cisco > Support > IP > IP Routing > Design > Design TechNotes > Introduction to EIGRP > Document ID: 13669

QUESTION 86

Which show interfaces command output indicates that the link may not be functional due to a Data Link layer issue, while the Physical layer is operational?

  1. Ethernet 0/0 is up, line protocol is up
  2. Ethernet 0/0 is up, line protocol is down
  3. Ethernet 0/0 is down, line protocol is up
  4. Ethernet 0/0 is down, line protocol is down

Correct Answer: B Section: (none) Explanation

Explanation/Reference:

Explanation:

The first or left-hand column (Ethernet 0/0 is up) indicates the Physical layer state of the interface, while the second or right-hand column (line protocol is down) indicates the Data Link layer state of the interface. The following command output excerpt indicates that the link is not functional due to a Data Link layer (or «line protocol») issue, while the Physical layer is operational:

Ethernet 0/0 is up, line protocol is down

If the problem were at the Data Link layer while the Physical layer is operational, the show interfaces command output will indicate that the interface is up, but the line protocol is down.

In the normal operation mode, when both Physical layer and Data Link layer are up, the show interfaces output will display the following message: Ethernet0/0 is up, line protocol is up

The message Ethernet 0/0 is down, line protocol is up is not a valid output.

The message Ethernet 0/0 is down, line protocol is down indicates that both the Physical layer and the Data Link layer are down. Therefore, this is an incorrect option.

Objective:

LAN Switching Fundamentals Sub-Objective:

Troubleshoot interface and cable issues (collisions, errors, duplex, speed) References:

QUESTION 87

Which of the following topologies is used in Wide Area Networks (WANs)?

  1. FDDI
  2. CDDI
  3. SONET
  4. Token Ring

Correct Answer: C Section: (none) Explanation

Explanation/Reference:

Explanation:

Synchronous Optical NETwork (SONET) is the standard topology for fiber optic networks. Developed in 1980s, SONET can transmit data at rates of up to 2.5 gigabits per second (Gbps).

All other options are incorrect because they are LAN topologies, not WAN topologies.

Fiber Distributed Data Interface (FDDI) specifies a 100-Mbps dual-ring fiber optics-based token-passing LAN. FDDI is typically implemented for high-speed LAN backbones because of its support for high bandwidth.

Copper Distributed Data Interface (CDDI) is copper version of FDDI. They differ only in that FDDI can span longer distances than CDDI due to the attenuation characteristics of copper wiring.

Token Ring/IEEE 802.5 LAN technology was developed by IBM in 1970. Token-ring LAN technology is based on token-passing, in which a small frame, called a token, is passed around the network. Possession of the token grants the node the right to transmit data. Once the data is transmitted, the station passes the token to the next end station.

Objective:

Network Fundamentals Sub-Objective:

Compare and contrast network topologies

References:

Cisco>Home>Cisco Documentation > Internetworking Technology Handbook>WAN Technologies

QUESTION 88

Which of the following is the correct command to define a default route using a gateway address of 172.16.0.254?

A. ip default-route 172.16.0.254 255.255.0.0

B. ip route 0.0.0.0 0.0.0.0 172.16.0.254

C. default-gateway 172.16.0.254

D. ip route default 172.16.0.254

Correct Answer: B Section: (none) Explanation

Explanation/Reference:

Explanation:

The ip route command is used to manually define a static route to a destination network. The syntax of the command is as follows:

ip route [destination_network] [mask] [next-hop_address or exit interface] [administrative_distance] [permanent]

The attributes of the command are as follows:

destination_network: Defines the network that needs to be added in the routing table. mask: Defines the subnet mask used on the network.

next-hop_address: Defines the default gateway or next-hop router that receives and forwards the packets to the remote network.

administrative_distance (AD): States the administrative distance. Static routes have an AD of 1, which can be changed to change the priority of the route.

Creating a default route is accomplished by substituting 0.0.0.0 for both the [destination_network] and [mask] fields, yielding the following command to create a default route through host 172.16.0.254:

router(config)# ip route 0.0.0.0 0.0.0.0 172.16.0.254

Any route configured manually is considered a static route. Another example of a command that creates a non-default route is shown below:

router(config)# ip route 192.168.12.0 255.255.255.0 172.65.3.1

This command would instruct the router on which the command was executed to send any traffic for the 192.168.12.0/24 network to the router located at 172.65.3.1.

You can also affect the route by changing the administrative distance of the route. By default, all static routes have an AD of 1, making them preferable to routes learned from routing protocols. However, you can add the AD parameter at the end of the command as shown below, making the static route less desirable than one learned from a routing protocol such as RIP:

router(config)# ip route 192.168.12.0 255.255.255.0 172.65.3.1 150

One reason to configure the routes this way could be to make the static route a backup route to the route learned by RIP, such as when the static route is a less desirable route through a distant office.

Once the ip route command has been used to add either a static route or a static default route to a router, the routes should appear in the routing table. They will be indicated with an S next to a static route and an S* for a default static route. The first two examples from the explanation above would appear in the routing table as follows:

S*0.0.0.0/0 [1/0] via 172.16.0.254

S 192.168.12.0/24 [1/0] via 172.65.3.1

The ip default-route, default-gateway, and ip route default commands are incorrect because they are not valid Cisco IOS commands. Objective:

Routing Fundamentals

Sub-Objective:

Configure, verify, and troubleshoot IPv4 and IPv6 static routing

References:

Cisco > Cisco ASDM User Guide, 6.1 > Configuring Dynamic And Static Routing > Field Information for Static Routes

Cisco > Support > IP > IP Routing > Design > Design TechNotes > Specifying a Next Hop IP Address for Static Routes > Document ID: 27082

QUESTION 89

Which of the following statements is true with regard to SDN?

  1. It combines the control plane and the data plane
  2. It separates the data plane and the forwarding plan
  3. It implements the control plane as software
  4. It implements the data plane as software

Correct Answer: C Section: (none) Explanation

Explanation/Reference:

Explanation:

In Software-defined networking (SDN), the control plane is separated from the data (or forwarding) plane and is implemented through software. The data plane remains on each physical device but the control plane is managed centrally for all devices though software.

SDN does not combine the data and control plane. Instead it decouples them.

SDN does not separate the data plane and the forwarding plan. These are both names for the same plane; that is, a data plane is a forwarding plane. SDN does not implement the data plane as software. The data plane remains on each physical device.

Objective:

Infrastructure Management Sub-Objective:

Describe network programmability in enterprise network architecture

References:

Software Defined Networking: The Cisco approach

QUESTION 90

Which Cisco Internetwork Operating System (IOS) command is used to save the running configuration to non-volatile random access memory (NVRAM)?

  1. copy startup-config running-config
  2. move startup-config running-config
  3. copy running-config startup-config
  4. move startup-config running-config

Correct Answer: C Section: (none) Explanation

Explanation/Reference:

Explanation:

The copy running-config startup-config command is used to save the running configuration to NVRAM. This command will should always been run after making changes to the configuration. Failure to do so will result in the changes being discarded at the next restart of the router. When the router is restarted, the startup configuration file is copied to RAM and becomes the running configuration.

The copy startup-config running-config command is incorrect because this command is used to copy the startup configuration to the running configuration. The command would be used to discard changes to the configuration without restarting the router.

The move startup-config running-config and move startup-config running-config commands are incorrect because these are not valid Cisco IOS commands. There is no move command when discussing the manipulation of configuration files.

Objective:

Infrastructure Management Sub-Objective:

Perform device maintenance

References:

Cisco Documentation > RPM Installation and Configuration > IOS and Configuration Basics

QUESTION 91

Which option lists the given applications in the correct sequence of increasing bandwidth consumption?

  1. an interactive Telnet session on a server running an SAP application a voice conversation between PC-based VoIP services

a voice conversation between two IP phones while accessing an online video site

  1. a voice conversation between two IP phones while accessing an online video site an interactive Telnet session on a server running an SAP application

a voice conversation between PC-based VoIP services

  1. a voice conversation between PC-based VoIP services

a voice conversation between two IP phones while accessing an online video site an interactive Telnet session on a server running an SAP application

  1. an interactive Telnet session on a server running an SAP application

a voice conversation between two IP phones while accessing an online video site a voice conversation between PC-based VoIP services

Correct Answer: A Section: (none) Explanation

Explanation/Reference:

Explanation:

The correct sequence of increasing bandwidth consumption in the given scenario would be, from lowest to highest:

  1. an interactive Telnet session on a server running an SAP application
  2. a voice conversation between PC-based VoIP services
  3. a voice conversation between two IP phones while accessing an online video site

An interactive Telnet session uses the least amount of bandwidth of the three application examples because it mainly involves the transfer of text.

A voice conversation between IP phones, also known as voice over IP (VoIP) traffic, requires more bandwidth than Telnet. Voice traffic is delay-sensitive and benefits from Quality of Service (QoS) to ensure service quality.

A voice conversation between two IP phones while accessing an online video site would consume the most bandwidth. A voice conversation with real-time video exchange is the equivalent of real-time video traffic. Video traffic is real-time and benefits from dedicated bandwidth with QoS implementation to ensure quality.

Objective:

WAN Technologies Sub-Objective:

Describe basic QoS concepts

References:

Cisco Documentation > Internetworking Technology Handbook > Voice/Data Integration Technologies

QUESTION 92

Which command would be used to establish static translation between an inside local address 192.168.144.25 and an inside global address 202.56.63.102?

  1. router(config)#ip nat inside source static 192.168.144.25 202.56.63.102
  2. router(config)#ip source nat inside static local-ip 192.168.144.25 global-ip 202.56.63.102
  3. router(config)#ip nat static inside source 192.168.144.25 202.56.63.102
  4. router(config)#ip nat inside static source 192.168.144.25 202.56.63.102

Correct Answer: A Section: (none) Explanation

Explanation/Reference:

Explanation:

To establish a static translation between an inside local address 192.168.144.25 and an inside global address 202.56.63.102, you would use the ip nat inside source static 192.168.144.25 202.56.63.102 command executed in global configuration mode. The correct format of the command is:

ip nat inside source static local-ip global-ip

This static configuration can be removed by entering the global no ip nat inside source static command.

Simply executing the ip nat inside source command will not result in NAT functioning. The NAT process also has to be applied correctly to the inside and outside interfaces. For example if, in this scenario the Fa0/0 interface hosted the LAN and the S0/0 interface connected to the Internet the following commands would

complete the configuration of static NAT.

Router(config)#interface F0/0 Router(config-if)#ip nat inside Router(config-if)#exit Router(config)#interface S0/0 Router(config-if)#ip nat outside

The other options are incorrect because they are not valid Cisco IOS configuration commands. They all contain syntax errors. Objective:

Infrastructure Services Sub-Objective:

Configure, verify, and troubleshoot inside source NAT References:

QUESTION 93

How many IP addresses can be assigned to hosts in subnet 192.168.12.64/26?

  1. 32
  2. 62

C. 128

D. 256

Correct Answer: B Section: (none) Explanation

Explanation/Reference:

Explanation:

Subnet 192.168.12.64/26 has 62 IP addresses that can be assigned to hosts. The formula to calculate the available number of hosts is:

2n — 2 = x

Where n = the number of host bits in the subnet mask and x = the number of possible hosts.

You will subtract 2 from the hosts calculation to remove the first address (the network ID) and the last address (the broadcast ID) from the valid hosts range. These addresses are reserved as the network ID and the broadcast address, respectively, in each subnet.

An IP address has 32 available bits divided into four octets. In this scenario, the /26 indicates that the subnet mask is 26 bits long, or that 26 bits are reserved for the network portion of the address. This leaves 6 bits for the host addresses (32 — 26 = 6). The number of host addresses would be calculated as follows:

Number of hosts = 26 — 2 Number of hosts = 64 — 2 = 62

Another simple way of determining the number of hosts in a range, when the subnet mask extends into the last octet, is to determine the decimal value of the last bit in the subnet mask after converting it to binary notation. This process only works when the subnet extends into the last octet, meaning that the subnet is greater than /24. The /26 subnet mask equals 26 network bits and 6 hosts bits, written as follows:

11111111.11111111.1111111.11000000

The 1s represent network bits and the 0s represent host bits.

In this example, the 26th bit (read from left to right) has a decimal value of 64, indicating that this subnet has 64 addresses. Subtract 2 to represent the network and broadcast addresses (64 — 2 = 62). This shows that this subnet range can be used to address 62 hosts.

Network address: 192.168.12.0

Subnet Mask in decimal: 255.255.255.192

Subnet Mask in binary: 11111111.11111111.11111111.11000000

Hosts: 64 — 2 = 62

For subnet 192.168.12.64, the valid host range will start from 192.168.12.65 to 192.168.12.126. For the next subnet 192.168.12.128, the valid host range will start from 192.168.12.129 to 192.168.12.190.

To construct a subnet that would contain 32 addresses would require using a mask of 255.255.255.224. This mask would leave 5 host bits, and 25 — 2 = 32. To construct a subnet that would contain 128 addresses would require using a mask of 255.255.255.128. This mask would leave 7 host bits, and 27 — 2 = 128. To construct a subnet that would contain 256 addresses would require using a mask of 255.255.255.0. This mask would leave 8 host bits, and 2(8) — 2 = 256. Objective:

Network Fundamentals Sub-Objective:

Configure, verify, and troubleshoot IPv4 addressing and subnetting

References:

Cisco > Design Tech Notes > IP Routing > IP Addressing and Subnetting for New Users > Understanding IP Addresses > Document ID: 13788 Nooning, Thomas. «TechRepublic Tutorial: Subnetting a TCP/IP Network.» TechRepublic, 20 May 2003.

QUESTION 94

Examine the network diagram.

Which switch port(s) will be in a forwarding state? (Choose two.)

  1. SwitchA — Fa0/1 and Fa0/2
  2. SwitchA — Fa0/1
  3. SwitchA — Fa0/2
  4. SwitchB — Fa0/1
  5. SwitchB — Fa0/2

Correct Answer: AD Section: (none) Explanation

Explanation/Reference:

Explanation:

Both switch ports on Switch A and Fa0/1 on Switch B will be in a forwarding state. Switch A will become the STP root bridge due to its lower MAC address. All ports on the root bridge will become designated ports in a forwarding state. Switch B has redundant connectivity to the root bridge, and must block one of its interfaces to prevent a switching loop. Both interfaces are the same speed (FastEthernet), and thus their cost to the root is the same. Finally, the interface with the lowest number will become the forwarding port. F0/1 has a lower port number than F0/2, so F0/1 becomes a forwarding port, and F0/2 becomes a blocking port.

In this scenario there are only two switches in the diagram. However, if there were more switches and Switch A were not the root bridge, the result would be the same with regard to the ports between Swicth A and B. Whenever there are redundant links between switches, one of the four ports involved will be set to a blocking (or in the case of RSTP, discarding) mode. The logic will still be the same, since the cost to get to the root bridge will still be equal if the port speeds are equal.

Without STP (which can be disabled) operating on switches with redundant links, such as those in the figure, loops can and almost surely will occur. For example, if a host connected to SwitchA were to send an ARP request for the MAC address of a host connected to SwitchB, the request could loop and cause a broadcast storm, slowing performance dramatically. This would probably occur when any host connected to either switch sends a broadcast frame, such as a DHCP request.

Rapid Spanning Tree Protocol (RSTP) uses the term discarding for a switch port that is not forwarding frames.

Objective:

LAN Switching Fundamentals Sub-Objective:

Configure, verify, and troubleshoot STP protocols

References:

Cisco > Support > Technology Support > LAN Switching > Spanning Tree Protocol > Configure > Configuration Examples and TechNotes > Understanding and Configuring Spanning Tree Protocol (STP) on Catalyst Switches

QUESTION 95

Refer to the partial output of the show interfaces command:

What does the Serial 0 is administratively down, line protocol is down line indicate with certainty?

  1. There is no problem with the physical connectivity.
  2. There is a configuration problem in the local or remote router.
  3. There is a problem at the telephone company’s end.
  4. The shutdown interface command is present in the router configuration.

Correct Answer: D Section: (none) Explanation

Explanation/Reference:

Explanation:

The Serial 0 is administratively down, line protocol is down line in the output of the show interfaces command indicates the following:

The shutdown interface command is present in the router configuration. This indicates that the administrator might have manually shut down the interface by issuing the shutdown command.

A duplicate Internet Protocol (IP) address might be in use.

This line does not show that there is no problem with the physical connectivity. Since the interface is administratively shut down, there is no way of determining the operational status of the physical layer.

The Serial 0 is administratively down, line protocol is down line does not indicate a configuration problem in the local or remote router. A problem in the configuration of local or remote router would be indicated by the Serial 0 is up, line protocol is down message.

This line does not show that there is a problem at the telephone company’s end. Since the interface is administratively shut down, there is no way of determining the operational status of the physical layer or protocol layer on the other end of the line.

Objective:

Infrastructure Management Sub-Objective:

Use Cisco IOS tools to troubleshoot and resolve problems References:

QUESTION 96

The following exhibit displays the MAC address table of a switch in your network, along with the location of each device connected to the switch:

Which of the following frames will be flooded to all ports after it is received by the switch?

  1. source MAC: 12-34-56-78-9A-BD, destination MAC: 12-34-56-78-9A-BF
  2. source MAC: 12-34-56-78-9A-BF, destination MAC: 12-34-56-78-9A-BD
  3. source MAC: 12-34-56-78-9A-BF, destination MAC: 12-34-56-78-9A-BC
  4. source MAC: 12-34-56-78-9A-BC, destination MAC: 12-34-56-78-9A-BF

Correct Answer: C Section: (none) Explanation

Explanation/Reference:

Explanation:

The frame with a source MAC of 12-34-56-78-9A-BF and a destination MAC of 12-34-56-78-9A-BC would be sent to all ports because the destination MAC address is not already in the MAC address table.

The frame with a source MAC of 12-34-56-78-9A-BD and a destination MAC of 12-34-56-78-9A-BF would not be sent to all ports because the destination MAC address is in the MAC address table.

The frame with a source MAC of 12-34-56-78-9A-BF and a destination MAC of 12-34-56-78-9A-BD would not be sent to all ports because the destination MAC address is in the MAC address table.

The frame with a source MAC of 12-34-56-78-9A-BC and a destination MAC of 12-34-56-78-9A-BF would not be sent to all ports because the destination MAC address is in the MAC address table.

Objective:

LAN Switching Fundamentals Sub-Objective:

Interpret Ethernet frame format

References:

Cisco Press > Articles > Cisco Certification > CCNA Routing and Switching > Basic Data Transmission in Networks: MAC Tables and ARP Tables How do Switches Work?

QUESTION 97

Which command will display the Virtual LAN (VLAN) frame tagging method for a switch link?

  1. show vlan
  2. show vlan encapsulation
  3. show vtp status
  4. show interfaces trunk

Correct Answer: D Section: (none) Explanation

Explanation/Reference:

Explanation:

The show interfaces trunk command displays the list of trunk ports and the configured VLAN frame tagging methods. Sample output of the show interfaces trunk command would be as follows:

SwitchB# show interfaces trunk

Port Mode Encapsulation Status Native vlan Fa0/1 on 802.1q trunking 1

Fa0/2 on 802.1q trunking 1 Fa0/3 on 802.1q trunking 1

<<output omitted>>

The show vlan command displays the VLAN number, name, status, and ports assigned to individual VLANs. Although the command cannot be used to determine the frame tagging method used for each trunk, it can be used to determine which ports are trunk ports by the process of elimination.

In the output below, generated from a six-port switch, the missing port (Fa0/6) is a trunk port. For communication to be possible between the two VLANs configured on the switch, Fa0/6 must be connected to a router, and trunking must be configured on the router end as well. The command is also useful for verifying that a port has been assigned to the correct VLAN as it indicates in the VLAN column the VLAN to which each port belongs.

Switch# show vlan

Vlan name Status Ports

1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/4

58 vlan 58 active Fa0/5

The show vlan encapsulation command is not a valid command for Cisco switches.

The show vtp status command does not display VLAN frame tagging method. The command is used to verify the status of VTP. The output of the show vtp status command would be as follows:

Line 6 of the given output indicates that the switch is operating in VTP Client mode. There are three possible VTP modes in which a switch can operate: Server, Client, and Transparent.

In Server mode, any changes made in the switch, such as adding a VLAN, will be recorded in the local database and also passed on to the other switches, where the change will be added.

In Client mode, the switch will accept and record changes from switches in Server mode, but will not accept changes made on the local switch. In Transparent mode, the switch adds changes made locally to the database, but will not send or accept changes sent from other switches.

The mode in use could be a useful piece of information during troubleshooting. For example, if you were unsuccessfully attempting to add a VLAN to the database, the reason would be that the switch is in VTP Client mode. If you were adding a VLAN in Transparent mode, the VLAN would be added to the local database but fail to appear on the other switches. If the switch were in Transparent mode, Line 6 in the above output would appear as follows:

VTP Operating Mode: Transparent

Only switches operating in VTP Server mode can accept changes to the VLAN database. This situation could be corrected easily and a VLAN 50 could be successfully added at two different configuration prompts by executing the following commands:

At global configuration mode:

switchB# config t switchB(config)# vtp mode server switchB(config)# vlan 50

At VLAN configuration mode:

switchB# vlan database switchB(vlan)# vtp server switchB(vlan)# vlan 50

Objective:

LAN Switching Fundamentals Sub-Objective:

Configure, verify, and troubleshoot VLANs (normal/extended range) spanning multiple switches

References:

Cisco Press Home > Articles > Cisco Certification > CCNA > CCNA Self-Study (ICND Exam): Extending Switched Networks with Virtual LANs

QUESTION 98

View the following network diagram:

Which switch will become the root bridge?

  1. SwitchA
  2. SwitchB
  3. SwitchC
  4. The root bridge cannot be determined from the given information.

Correct Answer: A Section: (none) Explanation

Explanation/Reference:

Explanation:

SwitchA will become the root bridge. The bridge ID, also known as the switch ID, is used to elect the root bridge in a redundant network topology. The bridge ID has two components:

Switch’s priority number: Configured as 32768 on Cisco switches by default

Switch’s Media Access Control (MAC) address: The burnt-in hardware address of the network interface card

The switch with the lowest bridge ID is selected as the root bridge. If the same priority number is configured on two or more switches in the network, the switch with the lowest MAC address will become the root. Bridge Protocol Data Units (BPDUs) communicate the details of the switch with the lowest bridge ID in the network. The election process for the root bridge takes place every time there is a topology change in the network. A topology change may occur due to the failure of a root bridge or the addition of a new switch in the network. The root bridge originates BPDUs every two seconds, which are propagated by other switches throughout the network. BPDUs are used as keepalives between switches, and if a switch stops receiving BPDUs from a neighboring switch for ten intervals (20 seconds), it will assume a designated role for the network segment.

Neither SwitchB nor SwitchC will become the root bridge. Although both have an equal priority value to SwitchA (32768), the MAC addresses of SwitchB and SwitchC are higher than that of SwitchA.

The root bridge can be determined with the information given. If the diagram did not indicate MAC addresses, then the root bridge would not be able to be determined, since the priorities are equal.

Objective:

LAN Switching Fundamentals Sub-Objective:

Configure, verify, and troubleshoot STP protocols

References:

Cisco Documentation > Cisco 7600 Series Cisco IOS Software Configuration Guide, 12.2SX > Configuring STP and IEEE 802.1s MST > Understanding the Bridge ID

Support > Technology Support > LAN Switching > Spanning Tree Protocol > Configure > Configuration Examples and TechNotes > Understanding and Configuring Spanning Tree Protocol (STP) on Catalyst Switches

QUESTION 99

Which of the following statements are true of Class C IP addresses?

  1. The decimal values of the first octet can range from 192 to 223
  2. The decimal values of the first octet can range from 1 to 126
  3. The first octet represents the entire network portion of the address
  4. The first three octets represent the entire network portion of the address
  5. The value of the first binary place in the first octet must be 0
  6. The value of the first two binary places in the first octet must be 11

Correct Answer: ADF Section: (none) Explanation

Explanation/Reference:

Explanation:

A class C IP addresses will have the following characteristics:

The decimal values of the first octet can range from 192 to 223

The first three octets represent the entire network portion of the address The value of the first two binary place in the first octet must be 11

Class B IP addresses will have the following characteristics:

The decimal values of the first octet can range from 128 to 191

The first two octets represent the entire network portion of the address The value of the first two binary place in the first octet must be 10

Class A IP addresses will have the following characteristics: The decimal values of the first octet can range from 1 to 126

The first octet represents the entire network portion of the address The value of the first binary place in the first octet must be 0

Objective:

Network Fundamentals Sub-Objective:

Compare and contrast IPv4 address types

References:

Cisco > IP Routing > IP Addressing and Subnetting for New Users

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