Gateway Redundancy Questions

Here you will find answers to HSRP, VRRP and GLBP questions

Quick summary:

HSRP, VRRP, or GLBP is used to allow specific routers to appear as a single router to make the failover transparent to the end users.

Question 1:

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

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

Answer: B C E

Explanation:

To configure HSRP, a Layer 3 interface is needed. They can be:

- Routed port: a physical port configured as a Layer 3 port by entering the no switchport interface configuration command.
– SVI: a VLAN interface created by using the interface vlan vlan_id global configuration command and by default a Layer 3 interface.
– Etherchannel port channel in Layer 3 mode: a port-channel logical interface created by using the interface port-channel port-channel-number global configuration command and binding the Ethernet interface into the channel group.

Reference:

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

Question 2:

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

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

Answer: A C

Explanation:

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

B is not correct, only hosts using the default gateway address of 192.168.1.1 will have their traffic sent to Catalyst_A

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

Question 3:

You are a network technician, study the exhibit carefully. Both routers are configured for the Gateway Load Balancing Protocol (GLBP). Which statement is true?

A. The default gateway address of each host should be set to to the virtual IP address.
B. The default gateway addresses of both hosts should be set to the IP addresses of both routers.
C. The hosts will have different default gateway IP addresses and different MAC addresses for each.
D. The hosts will learn the proper default gateway IP address from Router RA.

Answer: A

Question 4:

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

A. DS1 will be the active router because it booted first.
B. DS1 will be the standby router because it has the lower IP address.
C. DS1 will be the active router because it has the lower priority configured.
D. DS2 will be the active router because it booted last.

Answer: A

Explanation:

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

Question 5:

HSRP is a Cisco-proprietary protocol developed to allow several routers (or multilayer switches) to appear as a single gateway address. Which two statements are true about the Hot Standby Router Protocol (HSRP)? (Choose two)

A – Load sharing with HSRP is achieved by creating multiple subinterfaces on the HSRP routers.
B – Routers configured for HSRP can belong to multiple groups and multiple VLANs.
C – All routers configured for HSRP load balancing must be configured with the same priority.
D – Load sharing with HSRP is achieved by creating HSRP groups on the HSRP routers.

Answer: B D

Question 6:

If you are a network technician, study the exhibit carefully. Which Virtual Router Redundancy Protocol (VRRP) statement is true about the roles of the master virtual router and the backup virtual router?

A – Router RA is the master virtual router, and Router RB is the backup virtual router. When Router RA fails, Router RB will become the master virtual router. When Router RA recovers, Router RB will maintain the role of master virtual router.
B – Router RA is the master virtual router, and Router RB is the backup virtual router. When Router RA fails, Router RB will become the master virtual router. When Router RA recovers, it will regain the master virtual router role.
C – Router RB is the master virtual router, and Router RA is the backup virtual router. When Router RB fails, Router RA will become the master virtual router. When Router RB recovers, RouterRA will maintain the role of master.
D – Router P4S-RB is the master virtual router, and Router RA is the backup virtual router. When Router P4S-RB fails, Router
RA will become the master virtual router. When Router RB recovers, it will regain the master virtual router role.

Answer: B

Explanation:

Router RA is the master virtual router because of its higher priority (110). By default, the pre-empting function is enabled so Router RB will become the master virtual router when RA fails; and when RA recovers, it will take the master role again.

Question 7:

You are a network technician, do you know which three statements are correct about a default HSRP configuration? (Choose three)

A – The Standby track interface priority is 10.
B – The Standby priority is 100.
C – The Standby hold time is 10 seconds.
D – Two HSRP groups are configured.

Answer: A B C

Question 8:

You work as a network technician at Technical Corporation. Your boss is interested in GLBP. Study the network topology exhibit carefully. Which three statements accurately describe this GLBP topology? (Choose three)

A – If RA becomes unavailable, RB will forward packets sent to the virtual MAC address of RA.
B – RA is responsible for answering ARP requests sent to the virtual IP address.
C – If another router were added to this GLBP group, there would be two backup AVGs.
D – RA alternately responds to ARP requests with different virtual MAC addresses.

Answer: A B D

Explanation:

If RA fails, the GLBP protocol informs RB to replace the AVG that is down. The new AVG (in this case RB) will forward the packet sent to the 0008.b400.0101 virtual mac address, so the client sees no disruption of service nor does it need to resolve a new MAC address for the default gateway. -> A is correct.

RA, which is the AVG, replies to the ARP requests from clients with different virtual MAC addresses, thus achieving load balancing -> B is correct.

RA is elected as the AVG and RB is elected as the standby virtual gateway. If another router is added to this GLBP group, it will become a backup AVG -> there is only one backup AVG -> C is not correct.

“RA alternately responds to ARP requests with different virtual MAC addresses” this is the way GLBP provides load balancing over multiple routers (gateways) using a single virtual IP address and multiple virtual MAC addresses. Which MAC address it returns depends on which load-balancing algorithm it is configured to use -> D is correct.