HSRP Questions Flashcards

1
Q

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

A

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.

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2
Q

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

HSRP_preempt.jpg

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

A

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.

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3
Q

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?

HSRP_track.jpg

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

A

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.

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4
Q

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?

HSRP_interface_down.jpg

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.

A

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.

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5
Q

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.

A

Answer: B C

B is correct according to http://www.cisco.com/en/US/docs/switches/lan/catalyst3550/software/release/12.1_19_ea1/configuration/guide/swhsrp.html

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:

HSRP_load_sharing.jpg

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.

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6
Q

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.

A

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

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7
Q

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

HSRP_show_ip_arp.jpg

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.

A

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).

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8
Q

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

A

Answer: E

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9
Q

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

A

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″.

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10
Q

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.

A

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.
(Reference: http://www.cisco.com/en/US/docs/ios/debug/command/reference/db_s1.html)

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.

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11
Q

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.

A

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.

(If you don’t know about these terms please read the explanation of Question 6)

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12
Q

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.

A

Answer: A B F

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13
Q

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.

A

Answer: D E

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.

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14
Q

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)

HSRP_STP.jpg

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.

A

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.

Also please read an example of HSRP load sharing in the explanation of Question 1 on this page.

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15
Q

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

A

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.

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16
Q

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

A

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.

(Reference and good resource: http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a0080094a91.shtml)

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17
Q

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.

A

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.

(Reference: http://www.cisco.com/en/US/docs/switches/lan/catalyst3550/software/release/12.1_12c_ea1/configuration/guide/swhsrp.html)

18
Q

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

A

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.

19
Q

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

A

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 (Please read the explanation of question 2 to understand more about this state).

20
Q

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

A

Answer: A C F

Explanation

Same as Question 2

21
Q

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

A

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.

22
Q

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.

A

Answer: C E

Explanation

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

To understand answer E please read the explanation of Question 7.

23
Q

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

A

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.

24
Q

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

A

Answer: E

Explanation

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

25
Q

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.

A

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.

(Reference and good resource: http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a0080094afd.shtml)

26
Q

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.

A

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.

27
Q

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?

HSRP_active_standby.jpg

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.

A

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.

28
Q

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

A

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.

29
Q

What three tasks must a network administrator perform to properly configure Hot Standby Routing Protocol (HSRP)? (Choose three)

A. Define the encapsulation type.
B. Define the standby router.
C. Define the standby IP address.
D. Enable the standby priority.

A

Answer: B C D

30
Q

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

A

Answer: C

31
Q

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

A

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.

32
Q

In which three HSRP states do routers send hello messages? (Choose three)

A. Learn
B. Speak
C. Standby
D. Listen
E. Active
F. Remove

A

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

33
Q

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

A

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.

34
Q

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

A

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.

(Reference: http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a0080094afd.shtml)

35
Q

During routine maintenance, it became necessary to shutdown G1/0/1 on DSW1. All other interface were up. During this time, DSW1 remained the active device for Vlan 102′s HSRP group. You have determined that there is an issue with the decrement value in the track command in Vlan 102′s HSRP group. What need to be done to make the group function properly?

A. The DSW1′s decrement value should be configured with a value from 5 to 15
B. The DSW1′s decrement value should be configured with a value from 9 to 15
C. The DSW1′s decrement value should be configured with a value from 11 to 18
D. The DSW1′s decrement value should be configured with a value from 195 to less than 205
E. The DSW1′s decrement value should be configured with a value from 200 to less than 205
F. The DSW1′s decrement value should be greater than 190 and less 200

A

Answer: C

Explanation:

The question clearly stated that there was an issue with the decrement value in VLAN 102 so we should check VLAN 102 on both DSW1 and DSW2 switches first. Click on the PC Console1 and PC Console2 to access these switches then use the “show running-config” command on both switches

DSW1>enable
DSW1#show running-config

DSW2>enable
DSW2#show running-config

HSRP_show_run

As shown in the outputs, the DSW1′s priority is 200 and is higher than that of DSW2 so DSW1 becomes active switch for the group. Notice that the interface Gig1/0/1 on DSW1 is being tracked so when this interface goes down, HSRP automatically reduces the router’s priority by a configurable amount, in this case 5. Therefore the priority of DSW1 goes down from 200 to 195. But this value is still higher than that of DSW2 (190) so DSW1 remains the active switch for the group. To make DSW2 takes over this role, we have to configure DSW1′s decrement value with a value equal or greater than 11 so that its result is smaller than that of DSW2 (200 – 11 < 190). Therefore C is the correct answer.

36
Q

During routine maintenance, G1/0/1 on DSW1 was shutdown. All other interface were up. DSW2 became the active HSRP device for Vlan101 as desired. However, after G1/0/1 on DSW1 was reactivated. DSW1 did not become the active HSRP device as desired. What need to be done to make the group for Vlan101 function properly?

A. Enable preempt on DSW1′s Vlan101 HSRP group
B. Disable preempt on DSW1′s Vlan101 HSRP group
C. Decrease DSW1′s priority value for Vlan101 HSRP group to a value that is less than priority value configured on DSW2′s HSRP group for Vlan101
D. Decrease the decrement in the track command for DSW1′s Vlan 101 HSRP group to a value less than the value in the track command for DSW2′s Vlan 101 HSRP group.

A

Answer: A

Explanation:

Continue to check VLAN 101 on both switches…

HSRP_show_run_2.jpg

We learned that DSW1 doesn’t have the “standby 1 preempt” command so it can’t take over the active role again even if its priority is the highest. So we need to enable this command on VLAN 101 of DSW1.

37
Q

DSW2 has not become the active device for Vlan103′s HSRP group even though all interfaces are active. As related to Vlan103′s HSRP group. What can be done to make the group function properly?

A. On DSW1, disable preempt
B. On DSW1, decrease the priority value to a value less than 190 and greater than 150
C. On DSW2, increase the priority value to a value greater 241 and less than 249
D. On DSW2, increase the decrement value in the track command to a value greater than 10 and less than 50.

A

Answer: B or C

Explanation:

HSRP_vlan103

The reason DSW2 has not become the active switch for Vlan103 is because the priority value of DSW1 is higher than that of DSW2. In order to make DSW2 become the active switch, we need to increase DSW2′s priority (to higher than 200) or decrease DSW1′s priority (to lower than 190).

38
Q

If G1/0/1 on DSW1 is shutdown, what will be the current priority value of the Vlan105′s group on DSW1?

A. 95
B. 100
C. 150
D. 200

A

Answer: A

Explanation:

Below is the output of VLAN 105:

HSRP_vlan105.jpg

If G1/0/1 on DSW1 is shutdown, its priority will decrease 55 so, its value will be 150 – 55 = 95

39
Q

What is the configured priority value of the Vlan105′s group on DSW2 ?

A. 50
B. 100
C. 150
D. 200

A

Answer: B

Explanation:

Below is the output of VLAN 105 of DSW2:

HSRP_vlan105_DSW2.jpg

We don’t see the priority of DSW2 so it is using the default value (100).

40
Q

During routine maintenance, it became necessary to shutdown G1/0/1 on DSW1 and DSW2. All other interface were up. During this time, DSW1 became the active device for Vlan104′s HSRP group. As related to Vlan104′s HSRP group, what can be done to make the group function properly?

A. On DSW1, disable preempt
B. On DSW2, decrease the priority value to a value less than 150
C. On DSW1, increase the decrement value in the track command to a value greater than 6
D. On DSW1, disable track command.

A

Answer: C

Explanation:

HSRP_vlan104

The question asks us how to keep the active role of DSW2. From the outputs, we learned that if both interfaces G1/0/1 of DSW1 and DSW2 are shutdown, the priority of DSW1 will be 150 – 1 = 149 and that of DSW2 will be 200 – 55 = 145 -> DSW1 will become the active switch.

The main point here is that we have to configure so in such a way that when both interfaces G1/0/1 of DSW1 and DSW2 are shutdown, the priority of DSW2 is still greater than that of DSW1. Therefore the priority value of DSW1 should be smaller than 145, or we have to configure the decrement value of DSW1 to a value greater than 6 ( 6 = 150 – 144) -> C is the correct answer.

Notice: To keep the active role of DSW2, we can disable “preempt” on DSW1 (answer A) so that it will not take over the active role when DSW1 is downed but it also means that VLAN 104 will not have active switch -> VLAN104 will fail.