SWITCH (642-813): HSRP Questions

[phanthanhphong]

Question 1

Which protocol specified by RFC 2281 provides network redundancy for IP networks, ensuring that user traffic immediately and transparently recovers from first-hop failures in network edge devices or access circuits?
A. ICMP
B. IRDP
C. HSRP
D. STP



Answer: C

Explanation

HSRP is a Cisco-proprietary protocol developed to allow several routers or multilayer switches to appear as a single gateway IP address. This protocol is described in RFC 2281.

Question 2

Which of the following HSRP router states does an active router enter when it is preempted by a higher priority router?
A. active
B. speak
C. learn
D. listen
E. init
F. standby

Answer: B

Explanation

First we should review all the HSRP States:

State	Description
Initial	This is the beginning state. It indicates HSRP is not running. It happens when the configuration changes or the interface is first turned on
Listen	The router knows both IP and MAC address of the virtual router but it is not the active or standby router. For example, if there are 3 routers in HSRP group, the router which is not in active or standby state will remain in listen state.
Speak	The router sends periodic HSRP hellos and participates in the election of the active or standby router.
Standby	In this state, the router monitors hellos from the active router and it will take the active state when the current active router fails (no packets heard from active router)
Active	The router forwards packets that are sent to the HSRP group. The router also sends periodic hello messages

Now let’s take an example of a router passing through these states. Suppose there are 2 routers A and B in the network; router A is turned on first. It enters the initial state. Then it moves to listen state in which it tries to hear if there are already active or standby routers for this group. After learning no one take the active or standby state, it determines to take part in the election by moving to speak state. Now it starts sending hello messages containing its priority. These messages are sent to the multicast address 224.0.0.2 (which can be heard by all members in that group). When it does not hear a hello message with a higher priority it assumes the role of active router and moves to active state. In this state, it continues sending out periodic hello messages.
Now router B is turned on. It also goes through initial and listen state. In listen state, it learns that router A has been already the active router and no other router is taking standby role so it enters speak state to compete for the standby router -> it promotes itself as standby router.
Now to our main question! We want router B to become active router so we set a higher priority number than the priority of A and ask router B to take over the role of active router (with the preempt command). Now router A will fall back to the speak state to compete for active or standby state -> it becomes standby router because its priority is now lower than that of router A. (Therefore answer B is correct).
Note: Suppose router A is in active state while router B is in standby state. If router B does not hear hello messages from router A within the holdtime, router B goes into speak state to announce its priority to all HSRP members and compete for the active state. But if at some time it receives a message from the active router that has a lower priority than its priority (because the administrator change the priority in either router), it can take over the active role by sending out a hello packet with parameters indicating it wants to take over the active router. This is called a coup hello message.


Question 3

Which three statements are true of a default HSRP configuration? (Choose three)
A. The Standby hello time is 2 seconds.
B. Two HSRP groups are configured.
C. The Standby track interface priority decrement is 10.
D. The Standby hold time is 10 seconds
E. The Standby priority is 100.
F. The Standby delay is 3 seconds.

Answer: C D E

Explanation

The table below shows the default values of popular HSRP parameters:

Feature	Default Setting
Standby group number	0
Standby MAC address	System assigned as: 0000.0c07.acXX, where XX is the HSRP group number
Standby priority	100
Standby delay	0 (no delay)
Standby track interface priority	10
Standby hello time	3 seconds
Standby holdtime	10 seconds

Note:
* Standby delay: If router A is the HSRP active router and then loses a link, which causes it to become standby router, and then the link comes back, the delay command causes router A to wait before it becomes active again. For example, with the “standby preempt delay minimum 30” command, it waits for 30 seconds for the router to become active.
* Standby track: For example, consider this configuration:
standby priority 150
standby track serial 0
An HSRP priority of 150 is configured with the standby priority command and HSRP is configured to track the state of interface Serial0. Because no decrement value is specified in the standby track command, the HSRP priority is decremented by the default value of 10 when the tracked interface goes down.


Question 4

hostname Switch1 interface Vlan10 ip address 172.16.10.32 255.255.255.0 no ip redirects standby 1 ip 172.16.10.110 standby 1 timers 1 5 standby 1 priority 130 hostname Switch2 interface Vlan10 ip address 172.16.10.33 255.255.255.0 no ip redirects standby 1 ip 172.16.10.110 standby 1 timers 1 5 standby 1 priority 120

HSRP was implemented and configured on two switches while scheduled network maintenance was performed.
After the two switches have finished rebooting, you notice via show commands that Switch2 is the HSRP active router. Which two items are most likely the cause of Switch1 not becoming the active router? (Choose two)
A. booting delays
B. standby group number does not match VLAN number
C. IP addressing is incorrect
D. premption is disabled
E. incorrect standby timers
F. IP redirect is disabled

Answer: A D

Explanation

When two routers are turned on at the same time, the router completes booting process first will take the active role. Without the “preempt” configured, even a new router with a higher priority cannot take over the active role.In the configuration of Switch1 we don’t see the “preempt” command configured.

Question 5

hostname Switch1 interface Vlan10 ip address 172.16.10.32 255.255.255.0 no ip redirects standby 1 ip 172.16.10.110 standby 1 timers msec 200 msec 700 standby 1 preempt

hostname Switch2 interface Vlan10 ip address 172.16.10.33 255.255.255.0 no ip redirects standby 1 ip 172.16.10.110 standby 1 timers msec 200 msec 750 standby 1 priority 110 standby 1 preempt

hostname Switch3 interface Vlan10 ip address 172.16.10.34 255.255.255.0 no ip redirects standby 1 ip 172.16.10.110 standby 1 timers msec 200 msec 750 standby 1 priority 150 standby 1 preempt

Refer to the exhibit. Three switches are configured for HSRP. Switch1 remains in the HSRP listen state. What is the most likely cause of this status?
A. this is normal operation
B. standby group number does not match VLAN number
C. IP addressing is incorrect
D. incorrect priority commands
E. incorrect standby timers

Answer: A

Explanation

Only Switch 1 is not configured with the priority so it will have the default priority of 100, which is smaller than that of Switch2 (110) and Switch3 (150). Moreover, both Switch2 and Switch3 have the “preempt” command so surely Switch3 becomes active router while Switch2 becomes standby router -> Switch1 will be in listen state.


Question 6

What are three possible router states of HSRP routers on a LAN? (Choose three)
A. Standby
B. Established
C. Active
D. Idle
E. Backup
F. Init

Answer: A C F


Question 7

Refer to the exhibit. Which configuration on the HSRP neighboring device ensures that it becomes the active HSRP device in the event that port fa1/1 on Switch_A goes down?

Switch_A(config-if)# ip address 10.10.10.1 255.255.255.0 Switch_A(config-if)# standby 1 priority 200 Switch_A(config-if)# standby 1 preempt Switch_A(config-if)# standby 1 track interface fa 1/1 Switch_A(config-if)# standby 1 ip 10.10.10.10

A.
Switch_B(config-if)#ip address 10.10.10.2 255.255.255.0
Switch_B(config-if)#standby 1 priority 200
Switch_B(config-if)#standby 1 preempt
Switch_B(config-if)#standby 1 ip 10.10.10.10
Switch_B(config-if)#standby 1 track interface fa 1/1
B.
Switch_B(config-if)#ip address 10.10.10.2 255.255.255.0
Switch_B(config-if)#standby 1 priority 200
Switch_B(config-if)#standby 1 ip 10.10.10.10
C.
Switch_B(config-if)#ip address 10.10.10.2 255.255.255.0
Switch_B(config-if)#standby 1 priority 195
Switch_B(config-if)#standby 1 preempt
Switch_B(config-if)#standby 1 ip 10.10.10.10
D.
Switch_B(config-if)#ip address 10.10.10.2 255.255.255.0
Switch_B(config-if)#standby 1 priority 190
Switch_B(config-if)#standby 1 ip 10.10.10.10
Switch_B(config-if)#standby 1 track interface fa 1/1

Answer: C

Explanation

Switch_A is not configured standby track priority value so it will use the default track priority of 10 -> When Switch_A goes down, its priority is 200 – 10 = 190 so Switch_B must be configured with a priority higher than 190. Also Switch_B must have the “preempt” command configured to take over the active state -> C is correct.
Note: Answer A is not correct because Switch_B has the same priority value of Switch_A, but the Switch_B’s ip address on the HSRP interface is higher (10.10.10.2 is higher than 10.10.10.1) so Switch_B will take over the active state of Switch_A even when Switch_A is still operational.


Question 8

Which two statements about the HSRP priority are true? (Choose two)
A. To assign the HSRP router priority in a standby group, the standby group-number priority priority-value global configuration command must be used.
B. The default priority of a router is zero (0).
C. The no standby priority command assigns a priority of 100 to the router.
D. Assuming that preempting has also been configured, the router with the lowest priority in an HSRP group would become the active router.
E. When two routers in an HSRP standby group are configured with identical priorities, the router with the highest configured IP address will become the active router.

Answer: C E

Explanation

The “no standby priority” command will reset the priority to the default value (100) -> C is correct.



Question 9

HSRP has been configured between two Company devices. Which of the following describe reasons for deploying HSRP? (Choose three)

A. HSRP provides redundancy and fault tolerance
B. HSRP allows one router to automatically assume the function of the second router if the second router fails
C. HSRP allows one router to automatically assume the function of the second router if the second router starts
D. HSRP provides redundancy and load balancing

Answer: A B D

Explanation

Answer A and B are correct because they are the functions of HSRP. I just want to mention about answer D. In fact answer D is not totally correct, in SWITCH only GLBP has the load-balancing feature. HSRP can only load-sharing by configuring some different HSRP groups. But answer D is the only choice left in this question so we have to choose it.

Question 10

Regarding high availability, with the MAC address 0000.0c07.ac03, what does the “03″ represent?
A. The GLBP group number
B. The type of encapsulation
C. The HSRP router number
D. The VRRP group number
E. The HSRP group number
F. The active router number

Answer: E

Explanation

The last two-digit hex value in the MAC address presents the HSRP group number.


Question 11

Three Cisco Catalyst switches have been configured with a first-hop redundancy protocol. While reviewing some show commands, debug output, and the syslog, you discover the following information:

Jan 9 08:00:42.623: %STANDBY-6-STATECHANGE: Standby: 49: Vlan149 state Standby -> Active Jan 9 08:00:56.011: %STANDBY-6-STATECHANGE: Standby: 49: Vlan149 state Active -> Speak Jan 9 08:01:03.011: %STANDBY-6-STATECHANGE: Standby: 49: Vlan149 state Speak -> Standby Jan 9 08:01:29.427: %STANDBY-6-STATECHANGE: Standby: 49: Vlan149 state Standby -> Active Jan 9 08:01:36.808: %STANDBY-6-STATECHANGE: Standby: 49: Vlan149 state Active -> Speak Jan 9 08:01:43.808: %STANDBY-6-STATECHANGE: Standby: 49: Vlan149 state Speak -> Standby

What conclusion can you infer from this information?
A. VRRP is initializing and operating correctly.
B. HSRP is initializing and operating correctly.
C. GLBP is initializing and operating correctly.
D. VRRP is not properly exchanging three hello messages.
E. HSRP is not properly exchanging three hello messages.
F. GLBP is not properly exchanging three hello messages.

Answer: E

Explanation

These error messages describe a situation in which a standby HSRP router did not receive three successive HSRP hello packets from its HSRP peer (by default, hello messages are sent every 3 seconds while the holdtime is 10 seconds). The output shows that the standby router moves from the standby state to the active state. Shortly thereafter, the router returns to the standby state. Unless this error message occurs during the initial installation, an HSRP issue probably does not cause the error message. The error messages signify the loss of HSRP hellos between the peers. When you troubleshoot this issue, you must verify the communication between the HSRP peers. A random, momentary loss of data communication between the peers is the most common problem that results in these messages. HSRP state changes are often due to High CPU Utilization. If the error message is due to high CPU utilization, put a sniffer on the network and the trace the system that causes the high CPU utilization.


Question 12

You administer a network that uses two routers, R1 and R2, configured as an HSRP group to provide redundancy for the gateway. Router R1 is the active router and has been configured as follows:

R1#configure terminal R1(config)#interface fa0/0 R1(config-if)#ip address 10.10.0.5 255.255.255.0 R1(config-if)#standby 1 priority 150 R1(config-if)#standby preempt delay minimum 50 R1(config-if)#standby 1 track interface fa0/2 15 R1(config-if)#standby 1 ip 10.10.0.20

Which of the following describes the effect the “standby preempt delay minimum 50” command will have on router R1?
A. The HSRP priority for router R1 will increase to 200.
B. Router R1 will become the standby router if the priority drops below 50.
C. The HSRP priority for router R1 will decrease to 50 points when FaO/2 goes down.
D. Router R1 will wait 50 seconds before attempting to preempt the active router.

Answer: D

Explanation

If R1, for some reason, loses its active state, the “standby preempt delay minimum 50″ command will cause R1 to wait 50 seconds before it tries to get the active state again -> D is correct.


Question 13

Refer to the exhibit. HSRP has been configured and Link A is the primary route to router R4. When Link A fails, router R2 (Link B) becomes the active router. Which router will assume the active role when Link A becomes operational again?

A. The primary router R1 will reassume the active role when it comes back online.
B. The standby router R2 will remain active and will forward the active role to router R1 only in the event of its own failure.
C. The standby router R2 will remain active and will forward the active role to router R1 only in the event of Link B failure.
D. The third member of the HSRP group, router R3, will take over the active role only in event of router R2 failure.

Answer: A

Explanation

When R1 fails, the “standby 1 preempt” command on R2 will cause R2 to take over the active state of R1. But when R1 comes up again, the “standby 1 preempt” command on R1 will help R1 take over the active state again. Without the “preempt” command configured on R2, R2 only takes over the active state only if it receives information indicating that there is no router currently in active state (by default it does not receive 3 hello messages from the active router). Without the “preempt” command on R2, it will not become active router even if its priority is higher than all other routers.


Question 14

Which first-hop redundancy solution listed would supply clients with MAC address 0000.0C07.AC0A for group 10 in response to an ARP request for a default gateway?
A. IRDP
B. Proxy ARP
C. GLBP
D. HSRP
E. VRRP
F. IP Redirects


Answer: D

Explanation

The last two-digit hex value in the MAC address presents the HSRP group number. In this case 0A in hexa equals 10 in decimal so this router belongs to group 10 and it is running HSRP.

Question 15

What three tasks will a network administrator perform to successfully configure Hot Standby Routing Protocol? (Choose three)
A. Define the encapsulation type
B. Define the standby router
C. Define the IP address
D. Enable the standby mode
E. Enable HSRP


Answer: B C E


Question 16

You want to allow Router R1 to immediately become the active router if its priority is highest than the active router fails. What command would you use if you wanted to configure this?
A. en standby 1 preempt
B. standby 1 preempt enable
C. standby 1 preempt
D. hot standby 1 preempt

Answer: C


Question 17

Routers R1 and R2 are configured for HSRP as shown below:
Router R1:

interface ethernet 0 ip address 20.6.2.1 255.255.255.0 standby 35 ip 20.6.2.21 standby 35 priority 100 interface ethernet 1 ip address 20.6.1.1 255.255.255.0 standby 34 ip 20.6.1.21

Router R2:

interface ethernet 0 ip address 20.6.2.2 255.255.255.0 standby 35 ip 20.6.2.1 interface ethernet 1 ip address 20.6.1.2 255.255.255.0 standby 34 ip 20.6.1.21 standby 34 priority 100

You have configured the routers R1 & R2 with HSRP. While debugging router R2 you notice very frequent HSRP group state transitions. What is the most likely cause of this?
A. physical layer issues
B. no spanning tree loops
C. use of non-default HSRP timers
D. failure to set the command standby 35 preempt

Answer: A

Explanation

Both routers are not configured with the “preempt” command so by default they only take over the active state when they believe there is no active router (by default they don’t hear 3 successive hello messages from the active router). Therefore the most likely cause of this problem is a link failure between them (physical layer issue) -> A is correct.


Question 18

In which three HSRP states do routers send hello messages? (Choose three)
A. Learn
B. Speak
C. Standby
D. Listen
E. Active
F. Remove


Answer: B C E

Explanation

Speak state: sends hello messages to compete for the standby or active role.
Standby state: send hello messages to inform it is the standby router so that other routers (which are not active or standby router, in listen state) know the standby router is still there.
Active state: sends hello messages to indicate it is still up

Question 19

In the hardware address 0000.0c07.ac0a, what does 07.ac represent?
A. HSRP well-known physical MAC address
B. Vendor code
C. HSRP router number
D. HSRP group number
E. HSRP well-known virtual MAC address



Answer: E

Explanation

The HSRP standby IP address is a virtual MAC address which is composed of 0000.0c07.ac**. In which “**” is the HSRP group number in hexadecimal.

Question 20

Refer to the exhibit. Which two problems are the most likely cause of the exhibited output? (Choose two)

Vlan8 – Group 8 Local state is Active, priority 110, may preempt Hellotime 3 holdtime 10 Next hello sent in 00:00:01.168 Hot standby IP address is 10.1.2.2 configured Active router is local Standby router is unknown expired Standby virtual mac address is 0000.0c07.ac08 5 state changes, last state change 00:05:03

A. Transport layer issues
B. VRRP misconfiguration
C. HSRP misconfiguration
D. Physical layer issues
E. Spanning tree issues

Answer: C D

Explanation

When you see this error, it means the local router fails to receive HSRP hellos from neighbor router. Two things you should check first are the physical layer connectivity and verify the HSRP configuration. An example of HSRP misconfiguration is the mismatched of HSRP standby group and standby IP address.
Another thing you should check is the mismatched VTP modes.


Question 21

Which two statements are true about the Hot Standby Router Protocol (HSRP)? (Choose two)
A. Load sharing with HSRP is achieved by creating multiple subinterfaces on the HSRP routers.
B. Routers configured for HSRP can belong to multiple groups and multiple VLANs.
C. Load sharing with HSRP is achieved by creating HSRP groups on the HSRP routers.
D. All routers configured for HSRP load balancing must be configured with the same priority.
E. Routers configured for HSRP must belong to only one group per HSRP interface.

Answer: B C

Explanation

To load sharing with HSRP, we can divide traffic into two HSRP groups:
+ One group assigns the active state for one switch
+ The other group assigns the active state for the other switch
The example below shows how to load sharing with HSRP:

In this topology, R1 is the active router for Group 1 and is the standby router for Group 2 while R2 is the active router for Group 2 and is the standby router for Group 1. The configurations of R1 and R2 are shown below:

R1: interface fa0/1 //Group 1 ip address 192.168.1.2 standby 1 ip 192.168.1.1 standby 1 priority 150 standby 1 preempt standby 1 track Serial 0 ! interface fa0/0 //Group 2 ip address 192.168.2.2 standby 2 ip 192.168.2.1 standby 2 priority 145 standby 2 preempt

R2: interface fa0/1 //Group 2 ip address 192.168.2.3 standby 2 ip 192.168.2.1 standby 2 priority 150 standby 2 preempt standby 2 track Serial 0 ! interface fa0/0 //Group 1 ip address 192.168.1.3 standby 1 ip 192.168.1.1 standby 1 priority 145 standby 1 preempt

-> C is correct.
Note: An interface can belong to multiple HSRP groups, and the same HSRP group can be applied to different interfaces -> E is not correct.

Question 22

Refer to the exhibit. Assume that Switch_ A is active for the standby group and the standby device has only the default HSRP configuration. What conclusion is valid?

Switch_A(config-if)# ip address 10.10.10.1 255.255.255.0 Switch_A(config-if)# standby 1 priority 200 Switch_A(config-if)# standby 1 preempt Switch_A(config-if)# standby 1 track interface fa 1/1 Switch_A(config-if)# standby 1 ip 10.10.10.10

A. If port Fa1/1 on Switch_ A goes down, the standby device will take over as active.
B. If the current standby device were to have the higher priority value, it would take over the role of active for the HSRP group.
C. If port Fa1/1 on Switch_ A goes down, the new priority value for the switch would be 190.
D. If Switch_ A had the highest priority number, it would not take over as active router.

Answer: C

Explanation

By default, the standby track interface decrement is 10 so if interface fa1/1 goes down, the new priority value is 200 – 10 = 190

Question 23

Which statement best describes first-hop redundancy protocol status, given the command output in the exhibit?

A. The first-hop redundancy protocol is not configured for this interface.
B. HSRP is configured for group 10.
C. HSRP is configured for group 11.
D. VRRP is configured for group 10.
E. VRRP is configured for group 11.
F. GLBP is configured with a single AVF.

Answer: C

Explanation

The MAC address of the last IP is 0000.0c07.ac0b indicates HSRP has been configured for group 11 (0b in hexa = 11 in decimal).

Question 24

HSRP has been configured between two Company devices. What kind of message does an HSRP configured router send out every 3 seconds?
A. Retire
B. Coup
C. Resign
D. Send
E. Hello



Answer: E


Question 25

The following command was issued on a router that is being configured as the active HSRP router.
standby ip 10.2.1.1

Which statement is true about this command?
A. This command will not work because the HSRP group information is missing
B. The HSRP MAC address will be 0000.0c07.ac00
C. The HSRP MAC address will be 0000.0c07.ac01
D. The HSRP MAC address will be 0000.070c.ad01
E. This command will not work because the active parameter is missing

Answer: B

Explanation

The full syntax of the command above is:

standby [group-number] ip [ip-address [secondary]]

Therefore in the command “standby ip 10.2.1.1″ we recognize it is using the default group-number, which is 0 -> The last two-digit hex value of HSRP MAC address should be “00″.

Question 26

What can be determined about the HSRP relationship from the displayed debug output?

*Mar 1 00:12:16.871: SB11: Vl11 Hello in 172.16.11.112 Active pri 50 ip 172.16.11.115 *Mar 1 00:12:16.871: SB11: Vl11 Active router is 172.16.11.112 *Mar 1 00:12:18.619: %LINK-3-UPDOWN: Interface Vlan11, changed state to up *Mar 1 00:12:18.623: SB: Vl11 Interface up *Mar 1 00:12:18.623: SB11: Vl11 Init: a/HSRP enabled *Mar t 00:12:18.623: SB11: Vl11 Init-> Listen *Mar 1 00:12:19.619: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1 1, changed state to up *Mar 1 00:12:19.819: SB11: Vl11 Hello in 172.16.11.112 Active pri 50 ip 172.16.11.115 *Mar 1 00:12:19.819: SB11: V111 Listen: h/Hello rcvd from lower pri Active router (50/172.16.11.112) *Mar 1 00:12:22.815: SB11: Vl11 Hello in 172.16.11.112 Active pri 50 ip 172.16.11.115 *Mar 1 00:12:22.815: SB11: Vl11 Listen: h/Hello rcvd from lower pri Active router *Mar 1 00:12:25.683: SB11: Vl11 Hello in 172.16.11.112 Active pri 50 ip 172.16.11.115 *Mar 1 00:12:25.683: SB11: Vl11 Listen: h/Hello rcvd from lower pri Active router (50/172.16.11.112) *Mar 1 00:12:28.623: SB11: Vl11 Listen: d/Standby timer expired (unknown) *Mar 1 00:12:28.623: SB11: Vl11 Listen-> Speak *Mar 1 00:12:28.623: SB11: Vl11 Hello out 172.16.11.111 Speak pri 100 ip 172.16.11.115 *Mar 1 00:12:28.659: SB11: Vl11 Hello in 172.16.11.112 Active pri 50 ip 172.16.11.115 *Mar 1 00:12:28.659: SB11: Vl11 Speak h/Hello rcvd from lower pri Active router (50/172.16.11.112) *Mar 1 00:12:31.539: SB11: Vl11 Hello in 172.16.11.112 Active pri 50 ip 172.16.11.115 *Mar 1 00:12:31.539: SB11: Vl11 Speak h/Hello rcvd from lower pri Active router (50/172.16.11.112) *Mar 1 00:12:31.575: SB11: Vl11 Hello out 172.16.11.111 Speak pri 100 ip 172.16.11.115 *Mar 1 00:12:34.491: SB11: Vl11 Hello in 172.16 11.112 Active pri 50 ip 172.16.11.115

A. Router 172.16.11.112 will be the active router because its HSRP priority is preferred over router 172.16.11.111
B. Router 172.16.11.111 will be the active router because its HSRP priority is preferred over router 172.16.11.112
C. The IP address 172.16.11.111 is the virtual HSRP router IP address.
D. The IP address 172.16.11.112 is the virtual HSRP router IP address.
E. The nonpreempt feature is enabled on the 172.16.11.112 router.
F. The preempt feature is not enabled on the 172.16.11.111 router.

Answer: F

Explanation

To understand the output you should learn these terms:

Field	Description
SB	Abbreviation for “standby”
Vl11	Interface on which a Hot Standby packet was sent or received.
Hello in	Hello packet received from the specified IP address.
Hello out	Hello packet sent from the specified IP address.
pri	Priority advertised in the hello packet.
ip address	Hot Standby group IP address advertised in the hello packet.
state	Transition from one state to another.

From the output we learn:

Line	Debug output	Description
1	Vl11 Hello in 172.16.11.112 Active pri 50 ip 172.16.11.115	Priority of 172.16.11.112 is 50 (its standby IP address is 172.16.11.115)
2	Active router is 172.16.11.112	The current active router is 172.16.11.112
3	Interface Vlan11, changed state to up	Interface Vlan11 is turned on
6	Init-> Listen	Our router changes from Init to Listen state
15	Listen-> Speak	After the standby timer expired (line 14), our router changes from Listen to Speak state
16	Hello out 172.16.11.111 Speak pri 100 ip 172.16.11.115	Our router IP is 172.16.11.111, priority is 100 (its standby IP address is also 172.16.11.115)
18	Speak h/Hello rcvd from lower pri Active router	The Hellos received from lower priority Active router but our router does not send Coup message to take over active state

In short, our router (172.16.11.111) changes from Init -> Listen -> Speak state. It received hellos from the active router 172.16.11.112 with lower priority but it does not send Coup message to take over active state -> It is not configured with the “preempt” command.

Question 27

Refer to the exhibit. Based on the “debug standby” output in the exhibit, which HSRP statement is true?

*May 10 20:34:08.925: *SYS- 5-CONFIG_I: Configured from console by console *May 10 20:34:10.213: LINK-3-UPDOWN: Interface Vlan11, changed state to up *May 10 20:34:10.221: SB: Vl11 : Interface up *May 10 20:34:10.221: SB11: Vl11 Init: a/HSRP enabled *May 10 20:34:10.221: SB11: Vl11 Init -> Listen *May 10 20:34:11.213: LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan11 changed state to up *May 10 20:34:20.221: SB11: Vl11 Listen: c/Active timer expired (unknown) *May 10 20:34:20.221: SB11: Vl11 Listen -> Speak *May 10 20:34:20.221: SB11: Vl11 Hello out 10.10.10, 111 Speak pri 100 ip 10.10. 10.115 *May 10 20:34:28.905; SB11: Vl11 Hello out 10.10.10.111 Speak pri 100 ip 10.10. 10.115 *May 10 20:34:30.221: SB11: Vl11 Speak: d/Standby timer expired (unknown) *May 10 20:34:30.221: SB11: Vl11 Standby router is local *May 10 20:34:30.221; SB11: Vl11 Speak -> Standby *May 10 20:34:30.221; SB11: Vl11 Hello out 10.10.10.111 Standby pri 100 ip 10.10. 10.115 *May 10 20:34:30.221: SB11: Vl11 Standby: e/Active timer expired (unknown) *May 10 20:34:30.221: SB11: Vl11 Active router is local *May 10 20:34:30.221: SB11: Vl11 Standby router is unknown, was local *May 10 20:34:30.221: SB11: Vl11 Standby -> Active *May 10 20:34:30.221: %STANDBY-6- STATECHANGE: Vlan11 Group 11 state Standby -> Active *May 10 20:34:30.221: SB11: Vl11 Hello out 10.10.10.111 Active pri 100 ip 10.10. 10.115 *May 10 20:34:33.085: SB11: Vl11 Hello out 10.10.10.111 Active pri 100 ip 10.10. 10.115

A. DSW111 is the active router because it is the only HSRP-enabled router on that segment.
B. DSW111 is the active router because the standby timer has been incorrectly configured.
C. DSW111 is the active router because it has a lower priority on that VLAN.
D. DSW111 is the active router because it has a lower IP address on that VLAN.
E. DSW111 is the active router and is advertising the virtual IP address 10.10.10.111 on VLAN 11.

Answer: A

Explanation

From the output we learn that DSW111 moves from Init -> Listen -> Speak -> Standby -> Active and all the messages are “Hello out” (no messages are “Hello in”). This means that DSW111 is the only router sending messages in this segment.



Question 28

Refer to the exhibit. Based on the debug output shown in the exhibit, which three statements about HSRP are true? (Choose three.)

*Mar 1 00 16:43.095: %LINK-3-UPDOWN: Interface Vlan11, changed state to up *Mar 1 00 16:43.099: SB: Vl11 Interface up *Mar 1 00 16:43.099: SB11: Vl11 Init: a/HSRP enabled *Mar 1 00 16:43.099: SB11: Vl11 Init -> Listen *Mar 1 00 16:43.295: SB11: Vl11 Hello in 172.16.11.112 Active pri 50 ip 172.16.11.115 *Mar 1 00 16:43.295: SB11: Vl11 Active router is 172.16.11.112 *Mar 1 00 16:43.295: SB11: Vl11 Listen: h/Hello rcvd from lower pri Active router (50/172.16.11.112) *Mar 1 o o 16:43.295: SB11: Vl11 Active router is local, was 172.16.11.112 *Mar 1 00 16:43.299: %STANDBY-6-STATECHANGE: Vlan11 Group 11 state Listen -> Active *Mar 1 00 16:43.299: SB11: Vl11 Hello out 172.16.11.111 Active pri 100 ip 172.16.11.115 *Mar 1 00 16:43.303: SB11: Vl11 Hello in 172.16.11.112 Speak pri 50 ip 172.16.11.115 *Mar 1 00 16:46.207: SB11: Vl11 Hello out 172.16.11.111 Active pri 100 ip 172.16.11.115 *Mar 1 00 16:49.095: SB11: Vl11 Hello in 172.16.11.112 Speak pri 50 ip 172.16.11.115

A. The router with IP address 172.16.11.111 has preempt configured.
B. The final active router is the router with IP address 172.16.11.111.
C. The router with IP address 172.16.11.112 has nonpreempt configured.
D. The priority of the router with IP address 172.16.11.112 is preferred over the router with IP address 172.16.11.111.
E. The router with IP address 172.16.11.112 is using default HSRP priority.
F. The IP address 172.16.11.116 is the virtual HSRP IP address.

Answer: A B F

Question 29


Examine the router output above. Which two items are correct? (Choose two)
A. The local IP address of Router A is 10.1.0.6.
B. The local IP address of Router A is 10.1.0.20.
C. If Ethernet 0/2 goes down, the standby router will take over.
D. When Ethernet 0/3 of RouterA comes back up, the priority will become 105.
E. Router A will assume the active state if its priority is the highest.


Answer: D E

Explanation

The current state of this router is “active” and the standby router is 10.1.0.6, which makes answer A incorrect)
The IP address of the local router is not mentioned so we can’t conclude answer B. Notice that the IP 10.1.0.20 is just the virtual IP address of this HSRP group.
+ “Tracking 2 objects, 0 up” -> both Ethernet0/2 and 0/3 are currently down so the priority of RouterA was reduced from 120 to 95 (120 – 15 – 10). Therefore when Ethernet0/3 is up again, the priority of RouterA will be 95 + 10 = 105 -> D is correct.
From the line “preempt enabled” we learn this router is configured with “preempt” command so it will take over the active state if its priority is the highest -> E is correct. But a funny thing in this question is even when two interfaces are down, the priority of RouterA is still higher than the standby router so it is still the active router (the priority of standby router is 75). This also makes answer C incorrect.

Question 30

Refer to the exhibit. On the basis of the information provided in the exhibit, which two sets of procedures are best practices for Layer 2 and 3 failover alignment? (Choose two)

A. Configure the D-SW1 switch as the active HSRP router and the STP root for all VLANs. Configure the D-SW2 switch as the standby HSRP router and backup STP root for all VLANs.
B. Configure the D-SW1 switch as the standby HSRP router and the STP root for VLANs 11 and 110. Configure the D-SW2 switch as the standby HSRP router and the STP root for VLANs 12 and 120.
C. Configure the D-SW1 switch as the active HSRP router and the STP root for VLANs 11 and 110. Configure the D-SW2 switch as the active HSRP router and the STP root for VLANs 12 and 120.
D. Configure the D-SW2 switch as the active HSRP router and the STP root for all VLANs. Configure the D-SW1 switch as the standby HSRP router and backup STP root for all VLANs.
E. Configure the D-SW1 switch as the active HSRP router and the backup STP root for VLANs 11 and 110. Configure the D-SW2 switch as the active HSRP router and the backup STP root for VLANs 12 and 120.
F. Configure the D-SW1 switch as the standby HSRP router and the backup STP root for VLANs 12 and 120. Configure the D-SW2 switch as the standby HSRP router and the backup STP root for VLANs 11 and 110.

Answer: C F

Explanation

The “best practices for Layer 2 and 3 failover alignment” here means using load sharing of HSRP.
To load sharing with HSRP, we can divide traffic into two HSRP groups:
+ One group assigns the active state for one switch
+ The other group assigns the active state for the other switch
-> C and F are correct.

[phanthanhphong]

Question 31

Which three of the following network features are methods used to achieve high availability? (Choose three)
A. Spanning Tree Protocol (STP)
B. Delay reduction
C. Hot Standby Routing Protocol (HSRP)
D. Dynamic routing protocols
E. Quality of Service (QoS)
F. Jitter management

Answer: A C D

Explanation

STP, HSRP and dynamic routing protocols provide backup paths to reach the destination and achieve high availability.
Note: Quality of Service (Qos) only prioritizes specific type of data over other types and provides no high availability.

Question 32

Which command will ensure that R2 will be the primary router for traffic using the gateway address of 172.16.15.20?

A. On R2 add the command standby 1 priority 80
B. On R1 add the command standby 1 priority 110
C. On R1 add the command standby 1 priority 80
D. On R2 remove the command standby 1 preempt

Answer: C

Explanation

By default the priority value of HSRP is 100 so in order to ensure that R2 will be the primary router for traffic using the gateway address of 172.16.15.20 we can set the priority of R2 higher than 100 or set the priority of R1 lower than 100 -> only C is correct.


Question 33

Which command will need to be added to External_A to ensure that it will take over if serial 0/0 on External_B fails?

A. standby 1 priority 130
B. standby 1 preempt
C. standby 1 track fastethernet 0/0
D. standby 1 track 10.10.10.1

Answer: B

Explanation

The “standby 1 preempt” command on External_A router will make External_A take over the active state if it learns that its priority is higher than that of External_B router. In this case, when S0/0 interface of External_B fails, its priority will be 105 – 10 = 95, which is smaller than the default priority value (100) on External_A.

Question 34

Refer to the exhibit and the partial configuration on routers R1 and R2. Hot Standby Routing Protocol (HSRP) is configured on the network to provide network redundancy for the IP traffic. The network administrator noticed that R2 does not became active when the R1 serial0 interface goes down. What should be changed in the configuration to fix the problem?

A. The Serial0 interface on router R2 should be configured with a decrement value of 20.
B. The Serial0 interface on router R1 should be configured with a decrement value of 20.
C. R2 should be configured with a standby priority of 100.
D. R2 should be configured with a HSRP virtual address.

Answer: B

Explanation

When Serial0 of R1 goes down, the priority of R1 is still higher than that of R2 (115 – 10 = 105 > 100) so we should configured the decrement value of 20 on R1 with the command: standby 1 track Serial0 20.

Question 35

Three Cisco Catalyst switches have been configured with a first-hop redundancy protocol. While reviewing some show commands, debug output, and the syslog, you discover the following information:

Jan 9 08:00:42.623: %STANDBY-6-STATECHANGE. Standby: 49:Vlan149 state Standby -> Active Jan 9 08:00:56.011: %STANDBY-6-STATECHANGE. Standby: 49:Vlan149 state Active -> Speak Jan 9 08:01:03.011: %STANDBY-6-STATECHANGE. Standby: 49:Vlan149 state Speak -> Standby Jan 9 08:01:29.427: %STANDBY-6-STATECHANGE. Standby: 49:Vlan149 state Standby -> Active Jan 9 08:01:36.808: %STANDBY-6-STATECHANGE. Standby: 49:Vlan149 state Active -> Speak Jan 9 08:01:43.808: %STANDBY-6-STATECHANGE. Standby: 49:Vlan149 state Speak -> Standby

What conclusion can you infer from this information?
A. VRRP is initializing and operating correctly.
B. HSRP is initializing and operating correctly.
C. GLBP is initializing and operating correctly.
D. VRRP is not exchanging three hello messages properly.
E. HSRP is not exchanging three hello messages properly.
F. GLBP is not exchanging three hello messages properly.


Answer: E

Explanation

These error messages describe a situation in which a standby HSRP router did not receive three successive HSRP hello packets from its HSRP peer. The output shows that the standby router moves from the standby state to the active state. Shortly thereafter, the router returns to the standby state. Unless this error message occurs during the initial installation, an HSRP issue probably does not cause the error message. The error messages signify the loss of HSRP hellos between the peers. When you troubleshoot this issue, you must verify the communication between the HSRP peers. A random, momentary loss of data communication between the peers is the most common problem that results in these messages. HSRP state changes are often due to High CPU Utilization. If the error message is due to high CPU utilization, put a sniffer on the network and the trace the system that causes the high CPU utilization.
There are several possible causes for the loss of HSRP packets between the peers. The most common problems are physical layer problems, excessive network traffic caused by spanning tree issues or excessive traffic caused by each Vlan.


Question 36

Refer to the exhibit. Routers R1 and R2 are configured in an HSRP group to provide redundancy to the users on Network A. The T1 link between R1 and Network B has failed. How will HSRP respond to the failure?

R1# show running-config ! interface Ethernet0 ip address 171.16.6.5 255.255.255.0 standby 1 ip 171.16.6.100 standby 1 priority 105 standby 1 preempt standby 1 track Serial0 10 standby 1 track Serial1 10 ! interface Serial0 ip address 10.10.1.1 255.255.255.0 ! interface Serial1 ip address 10.10.3.3 255.255.255.0 ! <output omitted>

R2# show running-config ! interface Ethernet0 ip address 171.16.6.6 255.255.255.0 standby 1 ip 171.16.5 100 standby 1 preempt standby 1 track Serial0 10 ! interface Serial0 ip address 10.10.2.2 255.255.255.0 ! <output omitted>

A. R1 will change its priority but will remain active using the Frame Relay backup link to forward the traffic to Network B
B. R2 will assume the role of active router and will use its T1 link to forward the traffic to Network B
C. Both routers R1 and R2 will be active, and the traffic will be load balanced between the T1 links
D. Both routers R1 and R2 will be inactive, and the users on Network A will lose the connectivity to Network B

Answer: B

Explanation

On R1, interface E0 is configured with the priority of 105 (standby 1 priority 105) while interface E0 of R2 uses the default priority of 100 so R1 will become the active router. Both the routers are configured with “preempt” feature so if one of them has a higher priority than the active router, it assumes control as the active router.

Both the routers are configure to track interface S0 (connected R3 via T1 links) so if its T1 links fails, the hot standby priority on the device decreases by 10 (the default decrement value). In this case if T1 link connected to R1 fails its priority would be 105 – 10 = 95 and it is smaller than that of R2 (100, by default) so R2 will take the active role and send Network A traffic via its T1 link.

Question 37

Which high availability service is verified by the show standby command?

A. VRRP
B. GLBP
C. HSRP
D. MSTP
E. PVRST


Answer: C

Explanation

The syntax for VRRP and GLBP begins with “vrrp” and “glbp” respectively, for example: “vrrp 10 priority 110″; “glbp 10 priority 254″ while the syntax for HSRP is “standby …”, for example “standby 1 ip 10.10.10.1″.


Question 38


Observe the topology in the exhibit. HSRP is configured between RTB and RTC with RTC as the active router. SW2 is configured as the root bridge for the Spanning Tree Protocol. What will happen if the serial connection of RTC is down?
A. STP will not need to be recalculated because RTB will take over as active router
B. RTB and RTC will flap between active and standby because the timers for the STP are greater that the timers for HSRP
C. All traffic will automatically forward to RTB
D. SW3 will take over as the new root bridge

Answer: B

Explanation

To make the explanation easier we added port numbers to our routers and switches.

When S0/0 interface on RTC goes down, suppose RTC is tracking this interface and it is lost the active role. RTB will take the active role and turns on its Fa0/0 port. SW2 detects this link-state change and a spanning tree protocol transition takes place. The port Fa0/1 (on Sw2) takes approximately 30 seconds to go through the listening, learning, and forwarding stages. This time period exceeds the default timeouts of the HSRP hello processes so RTC, after reaching the Standby state, becomes Active because no hello packets were received from the RTB. Once again, the port Fa0/1 on Sw3 needs 30 seconds to reach final forwarding stage and that causes RTB tries to get the active role again -> Both RTB and RTC will flap between active and standby.
Note: HSRP changes its state when it fails to receive three consecutive HSRP hello packets from its peer. By default, hello timer is set to 3 seconds. That means a hello packet is sent between the HSRP standby group devices every 3 seconds, and the standby device becomes active when a hello packet has not been received for 10 seconds.

Note: Physical link-state changes caused by HSRP state changes occur specifically on the network module-Fast Ethernet (NM-FE) interfaces on Cisco 2600, Cisco 3600 and Cisco 7200 series routers. This behavior no longer occurs in Cisco IOS® Software release 12.1(3) and higher.

Question 39

What is the maximum number of HSRP standby groups that can be configured on a Cisco router?
A. 16
B. 32
C. 64
D. 128
E. 256



Answer: E


Question 40

You have just purchased a new Cisco 3550 switch running the enhanced IOS and need to configure it to be installed in a high availability network. Which three types of interfaces can be used to configure HSRP on a 3550 EMI switch? (Choose three)

A – BVI interface
B – routed port
C – SVI interface
D – Access port
E – EtherChannel port channel
F – Loopback Interface
Answer: B C E

Explanation:

To configure HSRP, a Layer 3 interface is needed. They can be:
- Routed port: a physical port configured as a Layer 3 port by entering the no switchport interface configuration command.
- SVI: a VLAN interface created by using the interface vlan vlan_id global configuration command and by default a Layer 3 interface.
- Etherchannel port channel in Layer 3 mode: a port-channel logical interface created by using the interface port-channel port-channel-number global configuration command and binding the Ethernet interface into the channel group.


Question 41

You work as a network technician , study the exhibit carefully. Which two statements are true about the output from the show standby vlan 50 command? (Choose two)

Catalyst_A# show standby vlan 50 VLAN50 – Group 1 Local State is Active, priority 200 may preempt Hellotime 3 sec, holdtime 10 sec Next hello sent in 1.302 Virtual IP address is 192.168.1.1 configured Active router is local Standby router is 192.186.1.11 expires in 9.443 Virtual MAC address is 0000.0c07.ac01 Authentication text ”AuthenKey” 2 state changes, last state change 00:11:30 IP redundancy name is “hsrp-Vl150-1″ (default)VLAN50 -Group 2 Local State is Standby , priority 100 Hellotime 3 sec, holdtime 10 sec Next hello sent in 0.98 Virtual IP address is 192.186.1.2 configured Active router is 192.168.1.11 , priority 200 expires in 6.334 Standby router is local Authentication text “AuthenKey” 3 state changes, last state change 0:09:30 IP redundancy name is “hsrp-Vl150-2″ (default)

A. Catalyst_A is load sharing traffic in VLAN 50.
B. Hosts using the default gateway address of 192.168.1.2 will have their traffic sent to Catalyst_A.
C. The command standby 1 preempt was added to Catalyst_A.
D. Hosts using the default gateway address of 192.168.1.1 will have their traffic sent to 192.168.1.11 even after Catalyst _A becomes available again.
Answer: A C

Explanation:

The output shows that the Catalyst_A switch is the active router for HSRP group 1 and the standby router for HSRP group 2 on interface VLAN 50. This means that another switch is the active router for HSRP group 2 on interface VLAN 50 -> A is correct, Catalyst_A is load sharing traffic in VLAN 50.

B is not correct, only hosts using the default gateway address of 192.168.1.1 will have their traffic sent to Catalyst_A
From the output, we notice that there is a line showing that “Local State is Active, priority 200 may preempt”. This indicates the command “standby 1 preempt” was added to Catalyst_A. If the active router (this router) fails, another router takes over its active role. The original active router is not allowed to resume the active role when it is restored until the new active router fails. Pre-empting allows a higher-priority router to take over the active role immediately.

Question 42

You are a network technician, study the exhibit carefully. Assume that Host PC can ping the Corporate Headquarters and that HSRP is configured on DS1, which is then reloaded. Assume that DS2 is then configured and reloaded. On the basis of this information, what conclusion can be drawn?

DS1# show running-config

interface Vlan10
ip address 10.10.10.2 255.255.255.0
no ip redirects
standby 60 priority 105
standby 60 ip 10.10.10.1
standby 60 track GigabitEthernet 0/1DS2# show running-config
interface Vlan10
ip address 10.10.10.3 255.255.255.0
no ip redirects
standby 60 priority 150
standby 60 ip 10.10.10.1
standby 60 track GigabitEthernet 0/1
A. DS1 will be the active router because it booted first.
B. DS1 will be the standby router because it has the lower IP address.
C. DS1 will be the active router because it has the lower priority configured.
D. DS2 will be the active router because it booted last.

Answer: A

Explanation:

The configuration does not have the “standby 60 preempt”command so the first booted router will take the active role with any priority.

Question 43

HSRP is a Cisco-proprietary protocol developed to allow several routers (or multilayer switches) to appear as a single gateway address. Which two statements are true about the Hot Standby Router Protocol (HSRP)? (Choose two)
A – Load sharing with HSRP is achieved by creating multiple subinterfaces on the HSRP routers.
B – Routers configured for HSRP can belong to multiple groups and multiple VLANs.
C – All routers configured for HSRP load balancing must be configured with the same priority.
D – Load sharing with HSRP is achieved by creating HSRP groups on the HSRP routers.

Answer: B D


Question 44

You are a network technician, do you know which three statements are correct about a default HSRP configuration? (Choose three)
A – The Standby track interface priority is 10.
B – The Standby priority is 100.
C – The Standby hold time is 10 seconds.
D – Two HSRP groups are configured.

Answer: A B C


Question 45

Which three protocols have been developed for IP routing redundancy to protect against first-hop router failure? (Choose three)

A. GLBP
B. ICMP
C. MSTP
D. HSRP
E. VRRP
F. NHRP

Answer: A D E

Explanation

All three protocols above are used for IP routing redundancy to protect against first-hop router failure. Some main differences of them are listed below:

HSRP: is a Cisco proprietary protocol.
VRRP: Open standard, created by IETF
GLBP: is a Cisco proprietary protocol. It is the only protocol (in three) supports load-balancing.