Practice Q's - HSRP Flashcards
You have configured switches A and B in a network.
The gigabitethernet0/1 interface of switch A has HSRP enabled on it for VLAN 30.
Switch A has a priority of 240 and switch B has a priority of 200 for the HSRP group.
You want to ensure that if the gigabitethernet0/1 interface of switch A goes down, then switch B becomes the active HSRP switch for the VLANs. You have executed the standby preempt command on switch B.
Which of the following commands should be used on switch A to achieve the desired results?
A. standby 30 track gigabitethernet0/1
B. standby 30 track gigabitethernet0/1 10
C. standby 30 track gigabitethernet0/1 30
D. standby 30 track gigabitethernet0/1 45
Answer: D
Explanation:
The standby 30 track gigabitethernet0/1 45 command should be used on switch A so that switch B becomes the active switch in case the gigabitethernet0/1 interface of switch A fails.
The standby track command allows you to track an HSRP-enabled interface on a switch. When the tracked interface fails or goes down, the priority of the active switch in the given HSRP group is decremented.
The default decrement value for the tracked interface is 10, which means that the priority value of the HSRP switch is decremented by 10. Additionally, if the standby preempt command is used on another switch, then that switch becomes the active switch for the group if it has a higher priority.
In this case, the standby 30 track gigabitethernet0/1 45 command decrements the HSRP priority of switch A for group 30 (VLAN 30) by 45 when gigabitethernet0/1 goes down. As a result, the priority of switch A is reduced to 195, which is less than the priority of switch B. Therefore, switch B now has the highest priority and hence becomes the active switch for the group.
The other options are incorrect, as they do not reduce the priority of switch A to an extent that the priority of switch B is higher.
You have configured three routers in HSRP group 10 to provide gateway redundancy for VLAN 56. Your intention was for Router 1 to be the active router in the group and for Router 3 to be the standby router.
Furthermore, in the event that Router 1 became unavailable, resulting in Router 3 becoming active, you intended for Router 1 to resume its role as active when it came back online.
However, you discover that in practice, Router 1 does NOT resume the active role when it comes back online.
What command should be executed on Router 1?
A. router1(config)# interface VLAN 56router1(config-if)# standby 10 preempt
B. router1(config)# interface VLAN 10router1(config-if)# standby 56 preempt
C. router1(config)# standby 10 preempt
D. router1(config)# standby 56 preempt
Answer: A
Explanation:
For Router 1 to resume its role as active when it comes back online, it must be configured to preempt the router with a lower priority.
In this scenario, Router 3 must have been configured with a lower priority than Router 1, or else it would have been the active router to begin with. To allow Router 1 to take back over as active, it must be configured with the following commands that will allow it to preempt the router with the lower priority:
- router1(config)# interface VLAN 56
- router1(config-if)# standby 1 preempt
This condition can be illustrated by executing the debug standby command on Router 1 as shown in the partial output below. The IP address of Router 1 is 192.168.11.112. The IP address of Router 3 is 192.168.11.150. The virtual IP address of the HSRP group is 192.168.11.156.
Router 1 sends a hello in line 1 of the output and receives its hello in line 2. Line 1 shows that Router 1 has a priority of 100. Line 2 shows that Router 3 (192.168.11.150) has a priority of 50.
Although Router 1 has a higher priority, it is not configured to preempt, so it will not be able to take the active role back from Router 3. If Router 1 were configured to preempt, there would be a series of output as shown below:
- SB:56:Vl56 Hello in 192.168.11.112 Active pri 100 ip 192.168.11.156*
- SB:56:Vl56 Active router is 192.168.11.112, was local*
If the HSRP router is the only HSRP router on the segment, then the output will show the router sending out hello packets with no hellos coming back.
The commands below are incorrect because the VLAN is 56, not 10, and the group number is 10, not 56:
- router1(config)# interface VLAN 10
- router1(config-if)# standby 56 preempt
The command below is incorrect because it is not executed under the VLAN 56 interface:
- router1(config)# standby 10 preempt
The command below is incorrect because it is not executed under the VLAN 56 interface and the HSRP number is incorrect:
- router1(config)# standby 56 preempt
The partial output displayed in the exhibit is a result of what IOS command? (Click on the Exhibit(s) button.)
A. switch# show running-config
B. switch# show standby vlan1 active brief
C. switch# show hsrp 1
D. switch# show standby
Answer: D
Explanation:
The command show standby produces the output displayed in the exhibit. This command displays information about HSRP on all configured interfaces and for all HSRP groups.
Important information in the exhibit includes that this router is the active router, the virtual IP address for the HSRP group is 172.16.1.20, the address of the standby router is 172.16.1.6, and the router is configured to preempt.
The command show running-config will display the complete configuration of the device, including the configuration of HSRP, but will not display the current status of HSRP on the switch.
The command show standby vlan 1 active brief provides a summary display of all HSRP groups on the switch that are in the active state. This output would provide basic information, not nearly the detail indicated in the exhibit.
The following is an example of output for show standby vlan 1 active brief:
- Interface Grp Prio P State Active addr Standby addr Group addr*
- Vlan1 0 120 Active 172.16.1.5 Unknown 172.16.1.20*
The command show hsrp 1 is not valid due to incorrect syntax.
You have been assigned to create a plan to implement HSRP on the router connecting your company’s network to the Internet. The router should be the active router in the HSRP group. On the active router, the following conditions should be met:
- Enable preemption with no delay
- Set Hello timer to 10 seconds and hold time to 25 seconds
- Set the priority to 150
Which of the following commands should be included in the plan to meet the given requirements?
(Choose all that apply.)
A. standby 1 preempt delay minimum 10
B. standby 1 preempt
C. standby 1 priority 150
D. standby 1 timers 10 25
E. standby 1 timers 25 10
F. standby track interface S0/1
Answer: B,C,D
Explanation:
The following commands should be included in the implementation plan to meet the given
requirements:
- standby 1 preempt
- standby 1 priority 150
- standby 1 timers 10 25
The standby 1 preempt command configures the preempt settings on the router. This command allows preemption without any delay.
The standby 1 priority 150 command sets the priority of the router to 150. The default priority of HSRP routers is 100. This implies that this router becomes the active router if there are no other routers in the group with a higher priority.
The standby 1 timers 10 25 command sets the Hello timer and the hold time on the local router. The first value, 10, specifies the Hello timer, and the second value, 25, indicates the hold time.
The most essential steps to configure HSRP on routers are as follows:
The standby 1 preempt delay minimum 10 command should not be included in the implementation plan. This command causes the router to preempt the active router after a minimum of 10 seconds. However, the requirement states that there should be no delay in preemption (a delay of 0 seconds), which is the default behavior.
The standby 1 timers 25 10 command should not be included in the implementation plan. This command sets the Hello timer to 25 seconds and the hold time to 10 seconds. However, the requirement is to set the Hello timer to 10 seconds and the hold time to 25 seconds.
The standby track interface S0/1 command should not be included in the implementation plan. This command enables tracking of the S0/1 interface on the local router. However, there is no requirement in the scenario to track an interface. Tracking can be used to decrement the priority of an HSRP router when the interface goes down. Using the default decrement value, if S0/1 were to go down, the priority of the router would be reduced by 10.
Assuming that preempt is not configured, when does a router in an HSRP group assume the role of the active router for the group?
A. A router in standby status will become the active router if it has a higher priority than the active router.
B. A router in standby status will become the active router when it does not detect three consecutive hello messages from the active router.
C. A router in standby status will become the active router when it does not detect any hello messages from the active router within the configured holdtime.
D. A router in listening status will become the active router when it does not detect any hello messages from the active router within the configured holdtime.
Answer: C
Explanation:
A router in standby status will become the active router when it does not detect any hello messages from the active router within the configured holdtime.
There are two ways for a router to become the HSRP active router. On startup, the router with the highest priority or IP address will become the active router.
If the active router fails, the HSRP standby router is a candidate to become the next active HSRP router. Failure of the active router is detected by the loss of hello messages for a configurable amount of time referred to as holdtime.
By default, hellos are sent every three seconds (hello time) and the holdtime is 10 seconds.
A router with the highest priority will be selected as the active router during the startup election process. If the active router fails and the standby router is promoted to be the active router, the first router will not immediately resume being the active router even if it has higher priority.
This characteristic can be overridden with the configuration option of preempt. The router with the highest priority can initiate a coup to become the active router in the group if it has preempt enabled in the configuration.
By default, all routers have an HSRP priority of 100. The range of values that can be assigned is 1 - 255.
To illustrate these concepts, consider the following example. Router A is configured with a priority of 150 and Router B is configured with a priority of 100.
Neither router is configured to preempt. If both routers were shut down and Router 5 was rebooted first, then Router B would become the active router. If Router A was then rebooted, it would not become the active router even though it has a higher priority than Router B, because it was NOT configured with the preempt command to allow it to assume the active role with a higher priority.
Which command enables HSRP on an interface?
A. hsrp
B. standby ip
C. standby mode hsrp
D. switchport mode hsrp
Answer: B
Explanation:
The standby ip interface configuration command enables Hot Standby Router Protocol (HSRP). The syntax for this command is as follows:
- switch(config-if)# standby group-number ip ip-address
The group-number argument specifies the HSRP group number on the interface. You do not need to enter a group number if there is only one HSRP group.
At least one interface on one of the routers in the group must be configured with the virtual IP address of the group. It is optional on all other interfaces on the other routers, which can learn the address through the hellos sent among the group.
A complete HSRP configuration is shown below with an explanation of each command.
- RouterA (config) #interface Fa0/1
- RouterA (config-if) # ip address 192.168.5.6 255.255.255.0
- RouterA (config-if) # standby 2 ip 192.168.5.10
- RourerA (config-if) # standby 2 priority 150
- RouterA (config-if) #standby 2 Preempt
- RouterA (config-if) #standby 2 track interface fa0/2
In the above, the router is tracking its own Fa0/1 interface. If that interface goes down it will reduce its priority by 10 (this is the default decrement when not specified). The new value would be 140 if that happened. To specify a decrement value, add it to the track command, as in this example:
- track interface Fa0/2 20.
When you configure routers to be part of an HSRP group, they listen for the HSRP MAC address for that group as well as their own burned-in MAC addresses.
HSRP uses the following MAC address:
0000.0c07.ac** (where ** is the HSRP group number)
The switchport mode interface configuration command will configure the VLAN membership mode of a port. It is not used to enable HSRP.
The options standby mode hsrp and hsrp are not valid commands.
Which statement best describes the function of Hot Standby Router Protocol (HSRP)?
A. HSRP specifies a single IP address that all routers in the group must use.
B. HSRP defines a set of routers that represent one virtual, fault-tolerant router.
C. HSRP provides a round-robin gateway selection process to increase fault tolerance.
D. HSRP defines a frame-tagging scheme that allows end stations to use any router as a gateway.
Answer: B
Explanation:
Hot Standby Router Protocol (HSRP) is specified by RFC 2281. The primary function of HSRP is to define a set of routers that work together to represent one virtual, fault-tolerant router. Thus, redundancy is provided in the event that any one of the routers fails. HSRP can be configured on the following interface types:
HSRP does use a single IP address to represent a group of routers, but this does not fully describe the function of HSRP.
HSRP does not provide round-robin gateway selection. HSRP uses router priority to select a primary and standby router.
HSRP does not define a frame-tagging scheme that allows end stations to use any router as a gateway. End stations use the virtual IP address of a group of HSRP routers as the default gateway.
Which of the following statements best describes the result of issuing the command standby 44 timers 3 1 on an HSRP router?
A. The holdtime will be set to a value of 3, and the hellotime will be set to a value of 1.
B. The status of the standby router will be displayed as unknown expired.
C. The role of active router will be passed repeatedly from one router to another.
D. The router will be configured to reassume the role of active router in the event that the router fails and is subsequently restarted.
Answer: C
Explanation:
When the command standby 44 timers 3 1 is issued on a Hot Standby Routing Protocol (HSRP) router, the role of active router will be passed repeatedly from one router to another. This behavior occurs when the timers are set incorrectly. The syntax for the standby timers command is
- standby [group-number] timers [hellotime holdtime].
The hellotime variable is the number of seconds between hello messages and is set to a value of 3 by default.
The holdtime variable is the number of seconds that the HSRP standby router will wait before assuming that the active router is down; if the standby router believes the active router to be down, it will assume the role of active router.
The holdtime is set to a value of 10 by default. The holdtime should be set to a value at least three times the value of the hellotime. Otherwise, the active router might not be able to respond before the standby router assumes that the active router is down and becomes the new active router.
Because the command standby 44 timers 3 1 sets the hellotime to a value of 3 and the holdtime to a value of 1, the role of active router will be passed from one standby router to the next. To set the holdtime to a value of 3 and the hellotime to a value of 1, the command standby 44 timers 1 3 should be issued. To reset the timer values to their default values, the command no standby group-number timers should be issued.
The status of the standby router will be displayed as unknown expired if a Physical layer problem exists. The unknown expired status can also be displayed if only one HSRP router is configured for the subnet.
To configure an HSRP router to reassume the role of active router in the event that the router fails and is subsequently restarted, the command standby group-number preempt should be issued.
When the HSRP active router fails or is shut down, the standby router assumes the role of active router. By default, when the original HSRP active router is restarted, it does not take the role of active router away from the original standby router, even if the original active router has a higher priority value. The command standby group-number preempt changes this default behavior.
The holdtime will not be set to a value of 3, and the hellotime will not be set to a value of 1. On the contrary, the hellotime will be set to a value of 3 and the holdtime will be set to a value of 1.
Refer to the following exhibit:
You have configured the routers in the diagram for HSRP, resulting in the displayed configurations.
Which of the following routers were configured with the default HSRP values for each command?
A. rtrA
B. rtrB
C. rtrC
D. rtrD
Answer: B
Explanation:
Only rtrB has the default HSRP settings. The default values for some of the important parameters for an HSRP-enabled router are listed in the following table:
HSRP ATTRIBUTE ——- DEFAULT VALUE
- PRIORITY —– 100
- HOLD TIME —– 10 SEC
- DECREMENT —– 10
- HSRP GROUP# —– 0
- PREEMPT DELAY —– 0 SEC
In this case, the routers have the default group number 0. The two routers rtrB and rtrC have the default priority value of 100, srtrB also has the default timer values, which are 3 seconds for the Hello timer and 10 seconds for the hold time.
The rtrA router is not configured with the default settings because the priority is set to 50, which is not the default value. In addition, the Hello timer is set to 10 seconds (default is 3 seconds) and the hold time is set to 3 seconds (default is 10 seconds)
The rtrC router is not configured with the default settings. Although the priority is 100, which is the default, the Hello timer is set to 10 seconds (default is 3 seconds) and the hold time is set to 3 seconds (default is 10 seconds).
The rtrD router is not configured with the default settings. It has a priority of 75 and the default is 100.
What command would provide the output displayed in the exhibit? (Click on the Exhibit(s) button.)
A. switch# show hsrp
B. switch# show standby
C. switch# show interface vlan
D. switch# show standby brief
Answer: D
Explanation:
The command show standby brief displays the output in the exhibit. It is used to display a summary of the HSRP groups of which the switch is a member. The summary information it provides includes the group number, priority, state, active device address, standby address, and group address. In the exhibit, the interface VLAN 64 is a member of HSRP group 2.
Its priority in the group is 100 and it is currently the standby switch. Since preemption is configured (as indicated by the P following the priority), we know that the priority of this switch must be lower than the priority of the active device. The active device has an IP address of 192.168.64.10 and the group IP address is 192.168.64.1.
The command show standby can be used to display detailed information about HSRP groups of which a switch is a member. It does not provide the quick summary display of the exhibit. This command displays information about HSRP on all configured interfaces and for all HSRP groups.
It also displays hello timer information and the expiration timer for the standby switch. The command syntax is
- show standby [type number [group]].
Below is an example of this command’s output:
In the above output, Router A is load-sharing traffic for VLAN 5. It is active for group 1 and standby for group 2. The router at address 192.168.23.3 is active for group 2 and standby for group 1. This allows traffic to be sent to both routers while still allowing for redundancy. Router A was also configured with the standby 1 preempt command (results seen in line 1), which allows it to resume its role as active for group 1 if it comes back up from an outage.
The command show interface vlan is not a complete command. A VLAN number must follow the command. When provided with a VLAN number, the output would display the status of the SVI, but no HSRP information.
The command show hsrp is not a valid command due to incorrect syntax.
Your network consists of one HSRP group of six routers. All of the routers are functioning properly.
The network has been stable for several days.
In which HSRP state are most of the routers?
A. Learn
B. Listen
C. Standby
D. Active
Answer: B
Explanation:
If all of the routers in the Hot Standby Routing Protocol (HSRP) group are functioning properly, then most of the routers in the group are in the listen state. Four routers will be in the listen state, one router will be in the standby state, and one router will be in the active state.
HSRP is used by a group of routers to create the appearance of a virtual router with which end stations can communicate in the event that the default gateway becomes unavailable. The active router is responsible for forwarding packets that are sent to the virtual router. The standby router is
responsible for assuming the role of active router should the active router fail or become unavailable. All other HSRP routers monitor the hello messages sent by the active and standby routers. Should the active and standby routers both become unavailable, the HSRP router with the highest priority is elected to become the active router by default. For routers with equal priority values, the router with the highest IP address becomes the active router.
HSRP routers can exist in one of the following six states:
All HSRP routers start in the initial state. A router in the learn state is waiting for its first hello message from the active router so that it can learn the virtual router’s IP address. When the hello message is received and the virtual router’s IP address is discovered, the HSRP router is in the listen state. A router in the listen state listens for hello messages from the active and standby routers. If an election for a new active router and a new standby router is required, then an HSRP router will enter the speak state and begin transmitting hello messages. The standby state is reserved for the standby router, and the active state is reserved for the active router. Only routers in speak, standby, and active states will transmit hello packets.
What command can be used on a Cisco switch to display the virtual MAC address for the HSRP groups of which the switch is a member?
A. switch# show standby mac
B. switch# show hsrp mac
C. switch# show standby
D. switch# show standby brief
Answer: C
Explanation:
The command show standby can be used to display the virtual MAC address for HSRP groups of which a switch is a member. This command displays information about HSRP on all configured interfaces and for all HSRP groups. It also displays hello timer information and the expiration timer for the standby switch. The standby switch will take over as the active switch if the timer expires before it hears a heartbeat from the active switch. Below is an example of the show standby command for the HSRP group 1:
In the above output, the following can be determined:
These routers have Ethernet hardware that only recognize a single MAC address. In either case, if for some reason this router becomes the standby router, such as due to loss of interfaces, then when the interfaces come back up it will be able to recover the active role because it is set for preemption, as shown on line 10.
The command show standby brief can be used to view summary information about HSRP groups of which the switch is a member. This information includes the group number, priority, state, active device address, standby address, and group address. It does not include the virtual MAC address.
The commands show standby mac and show hsrp mac are invalid due to incorrect syntax.
When executed on a HSRP group member named Router 10, what effect does the following command have?
- Router10(config-if)# standby 1 track serial0 25
A. It will cause the router to increase its HSRP priority by 25 if the Serial0 interface on the standby router goes down
B. It will cause the router to shut down the Serial0 interface if 25 packets have been dropped
C. It will cause the router to notify Router 25 is serial 0 goes down
D. It will cause the router to decrement its HSRP priority by 25 if Serial 0 goes down
Answer: D
Explanation:
This command will cause the router to decrement its HSRP priority by 25 if Serial 0 goes down.
Interface tracking can be configured in Hot Standby Routing Protocol (HSRP) groups to switch traffic to the standby router if an interface goes down on the active router.
This is accomplished by having the active router track its interface. If that interface goes down, the router will decrement its HSRP priority by the value configured in the command.
When properly configured, this will cause the standby router to have a higher HSRP priority, allowing it to become the active router and to begin serving traffic.
When the standby router in an HSRP group is not taking over the active role when the active router loses its tracked interface, it is usually a misconfigured decrement value, such that the value does not lower the HSRP priority of the active router far enough for the standby to have a superior priority value.
The command will not cause the router to increase its HSRP priority by 25 if the Serial0 interface on the standby router goes down. HSRP routers track their own interfaces, not those of another router.
The command will not cause the router to shut down the Serial0 interface if 25 packets have been dropped. It will only do this if the link becomes unavailable.
The command will not cause the router to notify Router 25 is serial 0 goes down. The number 25 in the command is the decrement value, not the ID of another router.
Which statement best describes the interaction between a workstation and an HSRP virtual router?
A. The workstation must have the real IP address of one of the HSRP routers defined as its defaultgateway.
B. The workstation must support IRDP in order to switch to the alternate router in an HSRP group.
C. The active HSRP router replies to the workstation’s ARP request with the virtual router’s MAC address.
D. The workstation sends packets to the active router’s real MAC address.
Answer: C
Explanation:
The active HSRP router replies to the workstation’s ARP request with the HSRP virtual MAC address. The HSRP virtual router presents a consistently available router to the end user,
reachable by a single unique, virtual MAC address. Only the active router responds to frames destined to this virtual MAC address, which identifies the HSRP group.
The primary function of HSRP is to define a set of routers that work together to represent one virtual, fault-tolerant router. Thus, redundancy is provided in the event that one of the routers fails.
An HSRP group consists of an active router and a standby router, which together present the appearance of a virtual router. The active router is elected from the routers configured to belong to the HSRP group. The virtual router’s MAC address identifies the virtual router, and the end user
will send packets to that destination MAC address. The end-user device will send an ARP request using the known IP address of its default gateway to discover the virtual router’s MAC address.
Only the active router will respond to the ARP request. The active router will then forward packets sent to the virtual router. The standby router monitors the status of the HSRP group and assumes packet-forwarding responsibilities of the virtual router if the active router fails.
Neither the workstation nor any other device is required to support ICMP Router Discovery Protocol (IRDP) in order to implement an HSRP virtual router. An IRDP-compliant device (RFC 1256) listens for IRDP hello messages, which advertise default routes.
It is not required for the workstation to know the actual IP address of any of the routers in the group. The end-user device will send an ARP request using the known IP address of its default gateway to discover the virtual router’s MAC address.
The workstation does not send packets to the active router’s real MAC address. It will send packets to virtual router’s MAC address.
Which of the following sets of commands CANNOT be included in the plan to implement HSRP on a Layer 3 switch port?
A. interface port-channelno switchport
B. interface fastethernetno switchportip address
C. interface fastethernetswitchport mode access
D. interface vlanip address
Answer: C
Explanation:
The following set of commands cannot be included in the implementation plan to configure HSRP on a Layer 3 switch port:
- interface fastethernet
- switchport mode access
This set of commands creates an access port on the switch. The access port can then be assigned to a VLAN. HSRP cannot be enabled on access ports. To enable HSRP on a switch port, the port has to be any of the following:
The interface port-channel and no switchport commands allow you to create a Layer 3 portchannel interface, which can be logically bound with other port-channel interfaces to form an EtherChannel. Port-channel interfaces can be configured as either Layer 2 or Layer 3 interfaces.
The interface port-channel command is used to create a Layer 3 port-channel interface.
The following set of commands creates a routed port:
- interface fastethernet
- no switchport
- ip address
Routed ports are physical Layer 3 interfaces that allow you to configure a switch as a router. The no switchport command allows the port to be used purely as a Layer 3 port. This command restarts the port thereby deleting any Layer 2 configuration settings on the switch.
The following set of commands is used to create an SVI, which is a logical interface that allows you to enable inter-VLAN routing on Layer 3 switches:
- interface vlan
- ip address
SVIs are configured as VLAN interfaces and have at least one physical interface assigned to the VLANs.
Which of the following statements are TRUE about the selection of the active router in an HSRP group? (Choose two.)
A. The router with the highest priority becomes the active router.
B. The router with the lowest priority becomes the active router.
C. The router with the highest IP address becomes the active router if the priorities of all routers are the same.
D. The router with the lowest IP address becomes the active router if the priorities of all routers are the same.
Answer: A,C
Explanation:
The following two statements are TRUE about the selection of the active router in an HSRP group:
All routers in an HSRP group have a priority. The default priority of HSRP routers is 100. However, HSRP routers can be assigned any value from 0 through 255 by using the standby priority command. The router with the highest priority becomes the active router of that HSRP group. The active router is responsible for forwarding packets to and from the virtual router (default gateway).
If the priorities of all the routers in the HSRP group are all the same, then the IP addresses of the routers are considered. The router with the highest IP address of an HSRP interface becomes the active router.
A standby router is also selected for the HSRP group. When the active router of the HSRP group fails, the standby router becomes the active router. You can decrement the priority of the active router if one of its interfaces goes down if you have enabled tracking for the respective HSRP interface.
Interface tracking can be enabled by using the standby track command. By default, the priority of the active router is decreased by 10 when it goes down.
When the original active router recovers the failed interface, it may become the active router again if the standby preempt command was used on the router. This command specifies that if the router has the highest priority in the HSRP group, then it is immediately selected as the active router for the group.
Therefore, if you want the original active router to resume the role when it comes online again, the standby preempt command should be used during its configuration.
Consider a network segment that has three routers rtrA, rtrB, and rtrC with HSRP enabled all of them. The rtrA router is selected as the active route, while rtrB is the standby router. The partial output of the show running-config command for rtrA is as follows:
Note that either router will be capable of assuming the role of active router if its priority becomes higher for the following reasons:
What command should you use to quickly view the HSRP state of the switch for all HSRP groups of which the switch is a member?
A. switch# show standby brief
B. switch# show ip interface brief
C. switch# show hsrp
D. switch# show standby
Answer: A
Explanation:
The command show standby brief should be used to quickly view the HSRP state of a switch for all HSRP groups of which it is a member. The summary information it provides includes the group number, priority, state, active device address, standby address, and group address.
The command show standby can be used to display detailed information about HSRP groups of which a switch is a member. This command would not provide a quick view. This command displays information about HSRP on all configured interfaces and for all HSRP groups. It also displays hello timer information and the expiration timer for the standby switch.
The command show ip interface brief is useful in that lists the interfaces and displays the basic IP configuration of each. This output would include the IP address of the interface and the state of the interface, but now HSRP information.
The command show hsrp is not a valid command due to incorrect syntax.
You are in the process of verifying the operation of your core switches, which are using HSRP.
One core switch was left with the default priority; the other was given a lower priority to make it the standby switch. The command show standby brief was executed on one of the switches. Output of the command is shown below:
What does this output mean? (Choose all that apply.)
A. this switch is using the default priority
B. this switch is the active HSRP switch
C. the HSRP devices are up and functioning correctly
D. the switch intended to be the active switch has failed and this switch has taken over
E. preemption is enabled for the group
Answer: B,D,E
Explanation:
The output in the exhibit indicates that this switch is the active HSRP switch, the switch intended to be the active switch has failed, and that preemption is enabled for the group.
This is the active switch because Active is the State listed for each interface that is a member of HSRP.
The question states that the switch that was intended to be the standby switch was given a priority lower than the default. The default priority is 100, so this is not the switch intended to be the active switch. This information indicates that the switch intended to be the active switch has failed.
Preemption is enabled, as indicated by the P following the priority value in line 2. Since preemption is enabled, the switch with the priority of 100 is still down. When that switch is corrected and joins the group again, it will take over as active.
The HSRP group is still providing access for users, but not all devices are functioning properly.
You are troubleshooting a problem with two routers configured in a HSRP group. You intended to configure the routers so that Router A and Router B would each track their respective Fa0/1
interfaces and decrement their priorities for several VLAN groups if the tracked interface went down. However, you find that Router A is not taking over as the active device for the HSRP group on VLAN 101 when the Fa0/1 interface on Router B fails.
Which command would NOT be useful for discovering the problem?
A. show running-configuration
B. show vlans
C. show standby brief
D. show standby
Answer: B
Explanation:
The show vlans command would NOT be useful for discovering the problem. When troubleshooting a problem with Hot Standby Router Protocol (HSRP), the show vlans command will yield no useful information. The output of the command is shown below, demonstrating that there is no HSRP information provided.
All three of the remaining commands will be useful in discovering information. Each is shown below with an example of its application to troubleshooting.
Example A:show running-configuration Router B is not taking over as the active device for VLAN 101’s HSRP group when the Fa0/1 interface on Router A fails. Below is a partial output of show run for both routers with the output focused on the section concerning VLAN 101’s configuration on each.
The above output displays the source of the problem. Router A has a decrement value of 5 configured for Fa0/1, as shown on the last line of the output after the specification of Fastethernet 0/1. This means that when its Fa0/1 interface goes down, Router A will subtract 5 from its priority for the VLAN 101 group, lowering it to 175. This is still higher than the priority of Router B, which is
- Therefore, the solution is to change the decrement value for Router A to at least 11. When the interface goes down, Router A’s priority will be decremented to 169, allowing Router B to take the role as active for the HSRP group in VLAN 101.
Example B:show standby brief
Router C is not taking over as the active device for VLAN 102’s HSRP group when the Fa0/1 interface on Router D fails. Below is a partial output of show standby brief for both routers C and D, with the output focused on the section concerning VLAN 102’s configuration on each.
Router C
- Interface Grp Prio P State Active addr Standby addr Group addr*
- Fa0/1 102 200 Active local 10.10.10.253 10.10.10.251*
Router D
- Interface Grp Prio P State Active addr Standby addr Group addr*
- Fa0/1 102 200 P Active local 10.10.10.253 10.10.10.251*
The absence of a P in the P (preempt) column in the output for Router C shows that it is not set to preempt. If not configured to preempt, it will never take over for Router D, regardless of its priority with respect to Router D.
Example C: show standby
Router F is supposed to be the active router for VLAN 103’s HSRP group. Occasionally both routers are shut down for maintenance over the weekend. After the routers are rebooted, Router F is not taking over as the active device for VLAN 103’s HSRP group.
Below is a partial output of the show standby command for both routers, with the output focused on the section concerning VLAN 103’s configuration on each
The output shows that Router F is not assuming the active role because of the priority and decrement values configured on the routers. When both routers go down, Router E will decrement its priority (200) by 10, as shown in last two lines of its output, leaving the priority at 190. Router F will decrement its priority (190) by 50 as shown in last two lines of its output, leaving the priority at 140.
Therefore, to ensure that Router F maintains its role as active even after the dual shutdowns, the priority of Router F should be increased to at least 241. When both routers decrement their priorities after shutdown, Router F will then have a priority of 191, which will be higher than the priority value of Router E.
Refer to the following partial output of the debug standby command on an HSRP-enabled router rtrA:
Which of the following information CANNOT be gathered from the given partial output?
A. IP address of the virtual router
B. IP address of the current active router
C. Priority of the active router
D. The tracked interfaces
Answer: D
Explanation:
The debug standby command does not provide any information about the tracked HSRP interfaces. This command displays information regarding the changes in the state of the HSRP routers and packet transmissions between the routers. Some of the information that you can view using the debug standby command is as follows:
HSRP packets contain the IP address of the virtual router. The IP address preceded by the text ip in the debug standby output is the address of the virtual router. In this case, the packets contain 10.5.5.5 after the text ip. This implies that 10.5.5.5 is the IP address of the virtual router.
After HSRP selects the active and standby routers for a group, only the active and standby routers send HSRP packets to the virtual router. If the active router fails, the standby router becomes the active router.
The text Hello in and the text Hello out indicate the hello packets received from and sent to the given IP address. Initially the router with IP address 10.5.5.1 is the active router, as indicated by the text Active router is 10.5.5.1.
The priority of the active router is 100, which is indicated by the text pri 100. However, when a hello packet from 10.5.5.2 is received, which has a higher priority (120) than the active router, the 10.5.5.2 router automatically and instantly becomes the active router. This implies that the router with the IP address 10.5.5.2 was the standby router and the standby preempt command was executed.
Ferris Plastics, Inc. is a medium sized company, with an enterprise network (access, distribution
and core switches) that provides LAN connectivity from user PCs to corporate servers. The
distribution switches are configured to use HSRP to provide a high availability solution.
- DSW1 –primary device for VLAN 101 VLAN 102 and VLAN 105
- DSW2 – primary device for VLAN 103 and VLAN 104
- A failure of GigabitEthemet1/0/1 on primary device should cause the primary device to release
its status as the primary device, unless GigabitEthernet1/0/1 on backup device has also failed.
Troubleshooting has identified several issues. Currently all interfaces are up. Using the running
configurations and show commands, you have been asked to investigate and respond to the
following question.
During routine maintenance, GigabitEthernet1/0/1 on DSW1 was shut down. All other interfaces
were up. DSW2 became the active HSRP device for VLAN 101 as desired. However, after
GigabitEthemet1/0/1 on DSW1 was reactivated, DSW1 did not become the active router for VLAN
101 as desired. What needs to be done to make the group for VLAN 101 function properly?
A. Enable preempt in the VLAN 101 HSRP group on DSW1.
B. Disable preempt in the VLAN 101 HSRP group on DSW2’s.
C. In the VLAN 101 HSRP group on DSW1, decrease the priority value to avaluethatis less‘than
the priority value configured in the VLAN 101 HSRP group on DSW2.
D. Decrease the decrement value in the track command for the VLAN 101 HSRP group on U
DSWTs to a values less than the value in the track command for the VLAN 101 HSRP group on
DSW2.
Answer: A
Explanation:
Ferris Plastics, Inc. is a medium sized company, with an enterprise network (access, distribution
and core switches) that provides LAN connectivity from user PCs to corporate servers. The
distribution switches are configured to use HSRP to provide a high availability solution.
- DSW1 –primary device for VLAN 101 VLAN 102 and VLAN 105
- DSW2 – primary device for VLAN 103 and VLAN 104
- A failure of GigabitEthemet1/0/1 on primary device should cause the primary device to release
its status as the primary device, unless GigabitEthernet1/0/1 on backup device has also failed.
Troubleshooting has identified several issues. Currently all interfaces are up. Using the running
configurations and show commands, you have been asked to investigate and respond to the
following question.
During routine maintenance, it became necessary to shut down the GigabitEthernet1/0/1 interface
on DSW1. All other interfaces were up. During this time, DSW1 remained the active device for the
VLAN 102 HSRP group. You have determined that there is an issue with the decrement value in
the track command for the VLAN 102 HSRP group. What needs to be done to make the group
function properly?
A. The decrement value on DSW1 should be greaterthan 5 and less than 15. 0
B. The decrement value on DSW1 should be greaterthan 9 and less than 15.
C. The decrement value on DSW1 should be greaterthan 11 and less than 19.
D. The decrement value on DSWTs should be greaterthan 190 and less than 200.
E. The decrement value on DSWTs should be greaterthan 195 and less than 205.
Answer: C
Explanation:
Use“show run”command to show. The left Vlan102 is console1 of DS1. Priority value is 200, we
should decrement value in the track command from 11 to 18. Because 200 – 11 = 189 < 190
(priority of Vlan102 on DS2).
Ferris Plastics, Inc. is a medium sized company, with an enterprise network (access, distribution
and core switches) that provides LAN connectivity from user PCs to corporate servers. The
distribution switches are configured to use HSRP to provide a high availability solution.
- DSW1 –primary device for VLAN 101 VLAN 102 and VLAN 105
- DSW2 – primary device for VLAN 103 and VLAN 104
- A failure of GigabitEthemet1/0/1 on primary device should cause the primary device to release
its status as the primary device, unless GigabitEthernet1/0/1 on backup device has also failed.
Troubleshooting has identified several issues. Currently all interfaces are up. Using the running
configurations and show commands, you have been asked to investigate and respond to the
following question.
All interfaces are active. DSW2 has not become the active device for the VLAN 103 HSRP group.
As related to the VLAN 103 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 200 and less than 250.
D. On DSW2, increase the decrement value in the track command to a value greater than 10 and less than 50.
”
Answer: C
Explanation:
From the output shown below of the HSRP status of DSW2, we see that the active router has a
priority of 200, while the local priority is 190. We need to increase the priority of DSW2 to greater
than 200, but it should be less than 250 so that if the gig 1/0/1 interface goes down, DSW1 will
become active. DSW2 is configured to decrement the priority by 50 if this interface goes down, so
the correct answer is to increase the priority to more than 200, but less than 250.
Ferris Plastics, Inc. is a medium sized company, with an enterprise network (access, distribution and core switches) that provides LAN connectivity from user PCs to corporate servers. The distribution switches are configured to use HSRP to provide a high availability solution.
- DSW1 –primary device for VLAN 101 VLAN 102 and VLAN 105
- DSW2 – primary device for VLAN 103 and VLAN 104
A failure of GigabitEthemet1/0/1 on primary device should cause the primary device to release its status as the primary device, unless GigabitEthernet1/0/1 on backup device has also failed.
Troubleshooting has identified several issues. Currently all interfaces are up. Using the running configurations and show commands, you have been asked to investigate and respond to the following question.
During routine maintenance, it became necessary to shut down the GigabitEthernet1/0/1 interface on DSW1 and DSW2. All other interfaces were up.
During this time, DSW1 became the active router for the VLAN 104HSRP group. As related to the VLAN 104 HSRP group, what can to 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, decrease the decrement value in the track command to a value less than 1.
”
Answer: C
Explanation:
We should NOT disable preempt on DS1. By do that, you will make Vlan104’s HSRP group fail
function. Example: if we are disable preempt on DS1. It can not become active device when
G1/0/1 on DS2 fail. In this question, G0/1/0 on DS1 & DS2 is shutdown. Vlan104 (left): 150 – 1 =
- Vlan104 (right): 200 – 155 = 145. Result is priority 149 > 145 (Vlan104 on DS1 is active). If
increase the decrement in the track value to a value greater than 6 (> or = 6). Vlan104 (left): 150 –
6 = 144. Result is priority 144 < 145 (vlan104 on DS2 is active).
Ferris Plastics, Inc. is a medium sized company, with an enterprise network (access, distribution and core switches) that provides LAN connectivity from user PCs to corporate servers. The distribution switches are configured to use HSRP to provide a high availability solution.
- DSW1 –primary device for VLAN 101 VLAN 102 and VLAN 105
- DSW2 – primary device for VLAN 103 and VLAN 104
A failure of GigabitEthemet1/0/1 on primary device should cause the primary device to release its status as the primary device, unless GigabitEthernet1/0/1 on backup device has also failed.
Troubleshooting has identified several issues. Currently all interfaces are up. Using the running configurations and show commands, you have been asked to investigate and respond to the following question.
What is the priority value of the VLAN 105 HSRP group on DSW2?
A. 50
B. 100
C. 150
D. 200
Answer: B
Explanation:
Use “show standby brief” command on console2. Very easy to see priority of Vlan105 is 100.
Ferris Plastics, Inc. is a medium sized company, with an enterprise network (access, distribution and core switches) that provides LAN connectivity from user PCs to corporate servers. The distribution switches are configured to use HSRP to provide a high availability solution.
- DSW1 -primary device for VLAN 101 VLAN 102 and VLAN 105
- DSW2 - primary device for VLAN 103 and VLAN 104
A failure–of GigabitEthemet1/0/1 on primary device should cause the primary device to release its status as the primary device, unless GigabitEthernet1/0/1 on backup device has also failed.
Troubleshooting has identified several issues. Currently all interfaces are up. Using the running configurations and show commands, you have been asked to investigate and respond to the following question.
If GigabitEthemet1/0/1 on DSW2 is shutdown, what will be the resulting priority value of the VLAN 105 HSRP group on router DSW2?
A. 90
B. 100
C. 150
D. 200
Answer: A
Explanation:
As seen below, the current priority for VLAN 105 is 100, and the tracking feature for Gig 1/0/0 is enabled which will decrement the priority by 10 if this interface goes down for a priority value of 90.
Your customer has asked you to come in and verify the operation of routers R1 and R2 which are configured to use HSRP. They have questions about how these two devices will perform in the event of a device failure.
What percentage of the outgoing traffic from the 172.16.10.0/24 subnet is being forwarded through R1?
A. R1-0%
B. R1-50 %, R2-50%
C. R2-100%
D. R1-100%
Answer: D
Explanation:
Based on the following output, we see that R1 is the active standby router for the Ethernet 0/0 link, so all outgoing traffic will be forwarded to R1.
Your customer has asked you to come in and verify the operation of routers R1 and R2 which are configured to use HSRP. They have questions about how these two devices will perform in the event of a device failure.
Refer to the exhibit. If router R1 interface Etherne0/0 goes down and recovers, which of the statement regarding HSRP priority is true?
A. The interface will have the priority decremented by 40 for HSRP group 1.
B. The interface will have the priority decremented by 60 for HSRP group 1
C. The interface will have its current priority incremented by 40 for HSRP group 1
D. The interface will have its current priority incremented by 60 for HSRP group 1
E. The interface will default to the a priority of 100 for HSRP group 1
Answer: C
Explanation:
Here is the HSRP configuration seen on R1:
Here, when the Ethernet 0/0 interface goes down, the standby 1 track decrement command will lower the priority from 130 to 90. However, when it comes back up, it will then increment it by 40 back to 130 for HSRP group 1.
Your customer has asked you to come in and verify the operation of routers R1 and R2 which are configured to use HSRP. They have questions about how these two devices will perform in the event of a device failure.
What issue is causing Router R1 and R2 to both be displayed as the HSRP active router for group 2?
A. The HSRP group number mismatch
B. The HSRP group authentication is misconfigured
C. The HSRP Hello packets are blocked
D. The HSRP timers mismatch
E. The HSRP group priorities are different
Answer: B
Explanation:
Based on the configuration output, we see that authentication is configured on R2, but not on R1:
This can be further verified by issuing the “show standby” command on each router.
Your customer has asked you to come in and verify the operation of routers R1 and R2 which are configured to use HSRP. They have questions about how these two devices will perform in the event of a device failure.
What is the virtual mac-address of HSRP group 1?
A. 0000.0c07.ac02
B. 4000.0000.0010
C. 0000.0c07.ac01
D. 4000.0000.ac01
E. 4000.0000.ac02
F. 0000.0c07.0010
Answer: B
Explanation:
Issuing the “show standby” command on either router shows us that the virtual MAC used by HSRP group 1 is4000.0000.0010 as shown below:
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 a nd 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:
Basically, each of the routers that provides redundancy for a given gateway address is
assigned to a common HSRP group. One router is elected as the primary, or active, HSRP
router, another is elected as the standby HSRP router, and all the others remain in the listen
HSRP state. The routers exchange HSRP hello messages at regular intervals, so they can
remain aware of each other’s existence, as well as that of the active router.
HSRP election is based on a priority value (0 to 255) that is configured on each router in the
group. By default, the priority is 100. The router with the highest priority value (255 is
highest) becomes the active router for the group. If all router priorities are equal or set to the
default value, the router with the highest IP address on the HSRP interface becomes the
active router. To set the priority, use the following interface configuration command:
Switch(config-if)# standby group priority priority
When HSRP is configured on an interface, the router progresses through a series of states
before becoming active. This forces a router to listen for others in a group and see where it
fits into the pecking order. The HSRP state sequence is Disabled, Init, Listen, Speak,
Standby, and, finally, Active.
You can configure a router to preempt or immediately take over the active role if its priority is
the highest at any time. Use the following interface configuration command to allow
preemption:
Switch(config-if)# standby group preempt [delay seconds]
Which option is the most likely explanation of the duplicate address message logged?
A. spanning-tree loop
B. HSRP misconfiguration
C. a PC with IP of 10.10.1.1
D. a hardware problem
Answer: B?
