First Hop Redundancy Protocols (HSRP and VRRP)

50 questions

All types50 Multiple choice25 Multiple select14 Ordering11

A network administrator is migrating a VLAN gateway infrastructure from VRRP to HSRP version 2 on Cisco IOS routers. Under the previous VRRP setup, Router R1 had its physical interface IP address configured as $192.168.10.1/24$ and served as the VRRP IP address owner by using $192.168.10.1$ as the virtual IP address.

During the migration, the administrator enters the following commands on Router R1's GigabitEthernet0/0 interface:
text
RouterR1(config)# interface gigabitethernet 0/0
RouterR1(config-if)# ip address 192.168.10.1 255.255.255.0
RouterR1(config-if)# standby version 2
RouterR1(config-if)# standby 10 ip 192.168.10.1

What is the outcome of executing the `standby 10 ip 192.168.10.1` command on Router R1?

Cisco IOS rejects using the interface physical IP address as the HSRP virtual IP address, resulting in a configuration error.

Router R1 accepts the command and automatically becomes the Active router with an unalterable priority of

255

The router accepts the command and automatically enables HSRP preemption to ensure primary forwarding status.

The command is accepted only if HSRP version 1 is configured instead of HSRP version 2.

Show answer & explanation

Answer: Cisco IOS rejects using the interface physical IP address as the HSRP virtual IP address, resulting in a configuration error.

Answer

Cisco IOS rejects using the interface physical IP address as the HSRP virtual IP address, resulting in a configuration error.

Unlike VRRP, which allows a router interface to be the IP address owner by assigning its physical IP address as the virtual IP address (which sets its priority automatically to

255

), Cisco HSRP (both v1 and v2) requires the virtual IP address to be an unused IP address on the IP subnet. Attempting to assign the local interface's physical IP address as the HSRP virtual IP address will be rejected by Cisco IOS.

Step-by-Step Solution

Analyze VRRP versus HSRP virtual IP address assignment rules.

VRRP allows a router to act as the IP address owner where the virtual IP address is identical to the router's physical interface IP address (assigning priority

255

). In contrast, Cisco HSRP (both v1 and v2) strictly requires the virtual IP address to be a unique IP address on the subnet that is not assigned to any physical router interface.

Understanding protocol design differences prevents invalid configurations during network migrations.

Evaluate the CLI command result on Router R1.

Entering `standby 10 ip 192.168.10.1` while GigabitEthernet0/0 has the physical IP address

192.168.10.1

causes Cisco IOS to generate an error indicating the virtual IP address cannot match the local physical IP address.

HSRP relies on distinct virtual and physical IP addressing to maintain dual operational capability for ARP and ICMP handling.

Key Concept

HSRP Virtual IP Address Uniqueness Constraint vs. VRRP IP Address Ownership

Estimated Time:1m 15s

Question 42Question →

A network engineer is comparing First Hop Redundancy Protocols (FHRP) for a multi-vendor enterprise network deployment. The evaluation focuses on the operational defaults and protocol parameters of Cisco HSRPv1 and industry-standard VRRPv2. Which two statements accurately describe the operational differences between HSRPv1 and VRRPv2? (Choose two.)

Select all that apply

VRRPv2 uses the multicast IP address 224.0.0.18 for control traffic, whereas HSRPv1 uses 224.0.0.2.

HSRPv1 allows the virtual IP address to be identical to an active router's physical interface IP address, whereas VRRPv2 strictly forbids matching physical interface IPs.

VRRPv2 enables preemption by default for the Master router role, whereas HSRPv1 disables preemption by default for the Active router role.

VRRPv2 uses virtual MAC addresses in the range 0000.0c07.acXX, whereas HSRPv1 uses virtual MAC addresses in the range 0000.5e00.01XX.

Show answer & explanation

Answer: VRRPv2 uses the multicast IP address 224.0.0.18 for control traffic, whereas HSRPv1 uses 224.0.0.2.; VRRPv2 enables preemption by default for the Master router role, whereas HSRPv1 disables preemption by default for the Active router role.

Answer

The correct options state that VRRPv2 uses multicast IP 224.0.0.18 while HSRPv1 uses 224.0.0.2, and that VRRPv2 has preemption enabled by default while HSRPv1 has preemption disabled by default.

The correct statements correctly identify key operational differences: VRRPv2 sends control advertisements to multicast IP 224.0.0.18 whereas HSRPv1 uses 224.0.0.2, and VRRPv2 has preemption enabled by default whereas HSRPv1 requires preemption to be explicitly configured.

Step-by-Step Solution

Analyze multicast destination IP address differences between HSRPv1 and VRRPv2.

HSRPv1 control traffic is destined to

224.0.0.2

(UDP port 1985). VRRPv2 control traffic is destined to

224.0.0.18

(IP protocol 112).

This confirms the statement regarding protocol multicast IP addressing is accurate.

Analyze default preemption behavior for both protocols.

VRRPv2 has preemption enabled by default. HSRPv1 has preemption disabled by default.

This confirms the statement regarding preemption defaults is accurate.

Evaluate distractor options concerning virtual IP assignment and virtual MAC address ranges.

VRRP allows virtual IP matching (IP address owner), while HSRP rejects it. HSRPv1 uses MAC prefix 0000.0c07.acXX, while VRRPv2 uses 0000.5e00.01XX.

Both incorrect choices swap the characteristic traits between HSRP and VRRP.

Key Concept

HSRPv1 vs VRRPv2 Protocol Characteristics and Defaults

Question 43Question →

A network administrator is designing a First Hop Redundancy Protocol (FHRP) deployment for a LAN segment. The design requirement dictates that the virtual default gateway IP address configured for host devices must be identical to the physical IP address assigned to the primary router's GigabitEthernet0/0 interface. Which protocol selection and operational characteristic accurately satisfies this design requirement?

VRRP, because it permits the virtual IP address to match a physical interface IP address, making that router the IP address owner with a default priority of 255.

HSRP version 1, because configuring an interface physical IP address as the standby IP address automatically elevates the router priority to 255.

HSRP version 2, because HSRPv2 updated its virtual MAC format to allow physical IP address mapping for backward compatibility.

Both HSRP and VRRP, because both protocols natively allow assigning an active router's physical IP address as the virtual gateway address.

Show answer & explanation

Answer: VRRP, because it permits the virtual IP address to match a physical interface IP address, making that router the IP address owner with a default priority of 255.

Answer

VRRP allows the virtual IP address to match a router's physical interface IP address, designating that router as the IP address owner with an effective priority of 255.

In VRRP, a router can be configured to use its own physical interface IP address as the virtual IP address for the redundancy group. When this occurs, the router becomes the IP address owner and its priority is fixed at 255, ensuring it acts as the Master router whenever its interface is active.

Step-by-Step Solution

Analyze the FHRP requirement for IP address ownership.

The scenario requires the virtual default gateway IP address to be identical to the primary router's physical interface IP address.

Different FHRP protocols have distinct rules regarding whether the virtual IP address can overlap with an interface's assigned physical IP.

Evaluate HSRP (v1 and v2) behavior regarding physical IP address assignment.

HSRP requires the virtual IP address to be a unique IP address on the subnet that is not assigned to any physical interface of the participating routers.

Attempting to assign a physical IP address as the HSRP virtual IP results in a CLI configuration error in Cisco IOS.

Evaluate VRRP (v2 and v3) behavior regarding physical IP address assignment.

VRRP explicitly supports assigning the physical interface IP address of a router as the VRRP virtual IP address.

When a router's physical IP matches the VRRP virtual IP, that router assumes the role of IP Address Owner and its operational priority is automatically set to 255 (the maximum possible priority).

Key Concept

VRRP IP Address Ownership vs HSRP Virtual IP Restrictions

Question 44Question →

A network administrator is monitoring an HSRP deployment on router R1 and executes the `show standby brief` command, obtaining the following output:

text
Interface Grp Pri P State Active Standby Virtual IP
Gi0/1 20 110 P Active local 192.168.20.3 192.168.20.1

Router R1 is configured to track interface GigabitEthernet0/0 with a priority decrement value of $20$ . Router R2 (currently the Standby router at $192.168.20.3$ ) has an HSRP priority of $100$ and has preemption enabled.

If interface GigabitEthernet0/0 on router R1 goes down, which operational change occurs on the local network segment?

Router R1's priority drops to

90

, causing Router R2 to preempt R1 and assume the Active role for HSRP group 20.

Router R1 remains the Active router because priority tracking decrements only trigger syslog alerts without changing active gateway ownership.

Router R1's priority drops to

90

, but Router R1 remains Active because a Standby router cannot preempt unless its priority exceeds the initial configured priority of

110

Router R1 automatically changes its virtual IP address to

192.168.20.3

to match the IP address of the Standby router.

Show answer & explanation

Answer: Router R1's priority drops to $90$ , causing Router R2 to preempt R1 and assume the Active role for HSRP group 20.

Answer

Router R1's priority drops to

90

, causing Router R2 to preempt R1 and assume the Active role for HSRP group 20.

When the tracked interface GigabitEthernet0/0 fails on router R1, HSRP interface tracking decrements R1's active priority by

20

, reducing it from

110

90

. Standby router R2 has a priority of

100

and preemption enabled. Because R2's priority (

100

) is now higher than R1's current priority (

90

), R2 preempts R1 and transitions to the Active state.

Step-by-Step Solution

Calculate Router R1's updated priority following the tracked interface failure.

Initial priority (

110

) minus decrement (

20

) =

90

HSRP interface tracking reduces the local priority by the specified decrement value when the tracked interface enters a down state.

Compare Router R1's new priority against Router R2's priority.

Router R1 priority (

90

) < Router R2 priority (

100

Router R2 now has a higher priority than Router R1 on the HSRP segment.

Evaluate preemption settings on Router R2 to determine state transition.

Router R2 preempts Router R1, becoming Active, while Router R1 transitions to Standby.

Because Router R2 has preemption enabled, it immediately takes over the Active role once its priority exceeds the current Active router's priority.

Key Concept

HSRP Interface Tracking and Preemption Failover Dynamics

Estimated Time:1m 30s

Question 45Question →

A network administrator is evaluating the operational parameters and default behaviors of First Hop Redundancy Protocols (FHRP) on Cisco IOS devices. Which two statements accurately describe default differences between VRRPv2 and HSRPv1?

Select all that apply

VRRP preemption is enabled by default, whereas HSRP preemption is disabled by default.

VRRPv2 uses the destination multicast IP address 224.0.0.18, whereas HSRPv1 uses 224.0.0.2.

HSRPv1 permits the configured virtual IP address to match a physical interface IP address on a participating router, whereas VRRP prohibits this configuration.

VRRP Master routers transmit advertisement packets every 3 seconds by default, whereas HSRP Active routers transmit hello packets every 1 second by default.

Show answer & explanation

Answer: VRRP preemption is enabled by default, whereas HSRP preemption is disabled by default.; VRRPv2 uses the destination multicast IP address 224.0.0.18, whereas HSRPv1 uses 224.0.0.2.

Answer

VRRP preemption is enabled by default while HSRP preemption is disabled by default, and VRRPv2 utilizes destination multicast address 224.0.0.18 while HSRPv1 utilizes 224.0.0.2.

VRRPv2 operates with preemption enabled by default and sends advertisements to multicast IP address 224.0.0.18. In contrast, HSRPv1 has preemption disabled by default (requiring explicit configuration) and sends hello messages to multicast IP address 224.0.0.2.

Step-by-Step Solution

Analyze preemption default settings for both protocols.

VRRP automatically enables preemption so that a router with higher priority assumes the Master role without manual CLI intervention. HSRP defaults to preemption disabled, requiring the 'standby <group> preempt' command.

Understanding protocol default behaviors is essential for predicting failover performance.

Analyze multicast addressing and transport mechanisms.

VRRPv2 uses multicast address 224.0.0.18 over IP protocol 112. HSRPv1 uses multicast address 224.0.0.2 over UDP port 1985.

Differentiating control plane encapsulation helps when analyzing packet captures or ACL filter requirements.

Evaluate IP address ownership rules.

VRRP supports IP address ownership where the virtual IP matches a router interface IP (priority 255). HSRP explicitly forbids assigning an active physical IP address as the virtual IP address.

Misinterpreting IP assignment rules causes CLI configuration errors when setting up HSRP virtual gateways.

Key Concept

HSRP and VRRP Feature and Default Parameter Comparison

Question 46Question →

A network administrator is migrating a gateway configuration from VRRP to HSRP Group 1 on a Cisco router. Under the previous VRRP setup, the virtual IP address was configured to match the physical IPv4 address of router R1's GigabitEthernet0/1 interface (192.168.10.1/24). The administrator attempts to enter the command `standby 1 ip 192.168.10.1` under interface GigabitEthernet0/1 on R1. What is the outcome of executing this command on Cisco IOS?

The router accepts the command and automatically sets R1's HSRP priority to 255 to designate it as the IP address owner.

Cisco IOS rejects the command because HSRP virtual IP addresses must be distinct from any physical IP address configured on the router interfaces.

The router accepts the command, but R1 remains permanently in the Speak state due to a virtual IP conflict.

The command is accepted only if preemption is manually disabled prior to executing the virtual IP assignment.

Show answer & explanation

Answer: Cisco IOS rejects the command because HSRP virtual IP addresses must be distinct from any physical IP address configured on the router interfaces.

Answer

Cisco IOS rejects the command because HSRP virtual IP addresses must be distinct from any physical IP address configured on the router interfaces.

In Cisco IOS HSRP implementation, the virtual IP address must be an unassigned IP within the local subnet and cannot match the physical IP address of any participating router interface. Attempting to set the HSRP virtual IP to the router interface's physical IP results in an immediate CLI configuration error.

Step-by-Step Solution

Analyze the operational differences regarding Virtual IP selection between VRRP and HSRP.

VRRP supports assigning an interface's physical IP address as the virtual IP (making that router the IP address owner with priority 255). HSRP does not support this and mandates an unused IP address within the subnet.

Understanding protocol specification constraints prevents configuration errors during migration.

Evaluate the Cisco IOS command behavior when attempting to assign a physical interface IP to an HSRP group.

Cisco IOS returns a configuration error stating that the virtual IP cannot be the same as the interface IP address.

HSRP requires a distinct virtual IP address to function correctly across active and standby nodes.

Key Concept

HSRP Virtual IP Addressing Rules vs VRRP IP Address Ownership

Question 47Question →

Place the HSRP (Hot Standby Router Protocol) router states in the correct chronological order as a newly configured router transitions from initial startup to becoming the active gateway.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct sequence of HSRP states from startup to active gateway is Initial, Listen, Speak, Standby, and Active.

During standard HSRP election and initialization, a router follows a strict 5-state progression: Initial (interface up), Listen (receiving peer Hello packets), Speak (actively sending Hello packets to compete in election), Standby (elected as primary backup), and Active (forwarding virtual IP traffic).

Step-by-Step Solution

Identify the initial configuration state upon interface activation.

Initial state is the first phase.

The protocol begins in Initial state when HSRP is first enabled or when an interface changes state to UP.

Determine the passive monitoring state prior to active participation.

Listen state comes second.

The router must first listen for existing active/standby Hello packets to determine if a gateway is already elected.

Identify when the router starts transmitting Hello messages.

Speak state comes third.

Once the router gathers initial group information, it enters Speak state to transmit Hello messages and enter the election.

Identify the election outcome role prior to active status.

Standby state comes fourth.

If the router has a higher priority than other non-active routers, it becomes the Standby router candidate.

Identify the final operational state responsible for packet forwarding.

Active state is the final phase.

The router transitions to Active state to process traffic sent to the virtual MAC and virtual IP address.

Key Concept

HSRP router state transitions and convergence lifecycle

Question 48Question →

A network engineer is comparing default operational behaviors between HSRPv1 and VRRPv2 across Cisco IOS switches. Which two statements accurately describe default characteristics and protocol specifications of these First Hop Redundancy Protocols? (Choose two.)

Select all that apply

VRRPv2 has preemption enabled by default, whereas HSRPv1 has preemption disabled by default.

HSRPv1 allows the virtual IP address to be configured using an IP address already assigned to a router's physical interface, whereas VRRPv2 explicitly rejects this configuration.

VRRPv2 generates virtual MAC addresses using the prefix 0000.5E00.01xx, whereas HSRPv1 uses the prefix 0000.0C07.ACxx.

HSRPv1 sends hello messages to multicast address 224.0.0.18, whereas VRRPv2 sends advertisements to multicast address 224.0.0.2.

Show answer & explanation

Answer: VRRPv2 has preemption enabled by default, whereas HSRPv1 has preemption disabled by default.; VRRPv2 generates virtual MAC addresses using the prefix 0000.5E00.01xx, whereas HSRPv1 uses the prefix 0000.0C07.ACxx.

Answer

The two correct statements are that VRRPv2 has preemption enabled by default while HSRPv1 has it disabled by default, and VRRPv2 uses virtual MAC addresses formatted as 0000.5E00.01xx while HSRPv1 uses 0000.0C07.ACxx.

VRRPv2 enables preemption by default and uses the virtual MAC prefix 0000.5E00.01xx. HSRPv1 disables preemption by default and uses the virtual MAC prefix 0000.0C07.ACxx.

Step-by-Step Solution

Evaluate default preemption state for HSRP and VRRP.

HSRPv1/v2 has preemption disabled by default (the active router remains active even if a higher-priority router joins). VRRPv2 has preemption enabled by default.

Protocol design choices differ regarding default failback behavior.

Analyze virtual MAC address structure for both protocols.

HSRPv1 uses 0000.0C07.ACxx, HSRPv2 uses 0000.0C9F.Fxxx, and VRRPv2 uses 0000.5E00.01xx.

Standardized virtual MAC ranges allow switches to map the virtual IP to unique Ethernet source/destination addresses.

Verify virtual IP matching constraints and multicast addresses.

VRRPv2 allows assigning a physical IP as virtual IP (IP address owner). HSRPv1 rejects assigning an interface's physical IP as the virtual IP. HSRPv1 uses multicast 224.0.0.2; VRRPv2 uses multicast 224.0.0.18.

Reversing these rules helps identify common misconceptions regarding protocol multicast endpoints and interface IP assignments.

Key Concept

HSRPv1 vs VRRPv2 Default Behaviors, Preemption, and Virtual Addressing

Question 49Question →

An engineer executes the following interface configuration on a Cisco IOS router:

text
R1(config)# interface GigabitEthernet0/0
R1(config-if)# ip address 10.1.1.1 255.255.255.0
R1(config-if)# standby 10 ip 10.1.1.1

What is the outcome of issuing the `standby 10 ip 10.1.1.1` command?

Cisco IOS rejects the command because HSRP virtual IP addresses cannot match the physical IP address assigned to an interface.

The command is accepted, and R1 automatically assumes the Active state with an operational priority of 255.

The command is accepted, but R1 remains stuck in the Speak state until a second router joins HSRP group 10.

The command is accepted, and Cisco IOS automatically enables HSRP preemption for group 10.

Show answer & explanation

Answer: Cisco IOS rejects the command because HSRP virtual IP addresses cannot match the physical IP address assigned to an interface.

Answer

Cisco IOS rejects the command because HSRP virtual IP addresses cannot match the physical IP address assigned to an interface.

In Hot Standby Router Protocol (HSRP), the virtual IP address must be unique within the subnet and cannot be identical to the physical IP address assigned to any interface of participating routers. When attempting to configure an HSRP virtual IP address that matches an existing interface IP address, Cisco IOS rejects the command with an explicit error.

Step-by-Step Solution

Analyze the interface IP configuration and the requested HSRP virtual IP.

The physical interface IP is set to 10.1.1.1/24, and the HSRP command attempts to assign 10.1.1.1 as the virtual IP address for HSRP group 10.

Identifying overlapping IP configurations is necessary to determine protocol compliance.

Compare HSRP rules against VRRP rules regarding IP address ownership.

In VRRP, a router can be the IP address owner and use its physical IP as the virtual IP (raising priority to 255). In HSRP, the virtual IP address MUST be an unused IP address within the subnet and cannot match any router's physical interface IP.

HSRP implementation rules require an unused virtual IP address on the subnet.

Determine CLI output behavior.

Cisco IOS displays an error message rejecting the `standby 10 ip 10.1.1.1` command.

Entering a matching IP address violates HSRP address assignment rules.

Key Concept

HSRP Virtual IP Address Constraints vs VRRP IP Owner Rules

Estimated Time:1m 0s

Question 50Question →

Two Layer 3 switches, Core-1 and Core-2, provide default gateway redundancy for hosts in VLAN 30 ( $10.30.0.0/24$ ). Core-1 is configured with physical interface IP address $10.30.0.2/24$ and Core-2 with $10.30.0.3/24$ . A network administrator enters the configuration command `standby 30 ip 10.30.0.2` on Core-1's VLAN 30 interface. Which outcome occurs when this command is executed?

The router rejects the command because HSRP does not allow the virtual IP address to match an IP address assigned to a physical interface.

The command is accepted, and Core-1 automatically raises its HSRP priority to 255 to become the permanent Active router.

The command is accepted into the running configuration, but Core-1 logs duplicate IP address conflict messages continuously.

The router accepts the command and dynamically derives a virtual MAC address using Core-1's physical burned-in MAC address.

Show answer & explanation

Answer: The router rejects the command because HSRP does not allow the virtual IP address to match an IP address assigned to a physical interface.

Answer

The command is rejected because HSRP virtual IP addresses cannot match any physical interface IP address configured on the router.

Cisco IOS/IOS-XE enforces a fundamental operational rule in HSRP: the virtual IP address must be unique within the subnet and cannot match the physical IP address of any router interface in the HSRP group. Attempting to assign an interface's physical IP address as the HSRP virtual IP results in an immediate CLI error rejecting the command.

Step-by-Step Solution

Analyze the HSRP virtual IP address configuration rule.

In Hot Standby Router Protocol (HSRP v1 and v2), the virtual IP address must be an unused IP address within the subnet assigned to the interface.

Assigning an existing physical interface IP address as the virtual IP would cause internal IP routing conflicts and ARP table ambiguities on the local router.

Compare HSRP behavior with VRRP.

While Virtual Router Redundancy Protocol (VRRP) allows a router to act as the IP address owner by assigning its physical IP address as the virtual IP (setting priority to 255), HSRP explicitly forbids this.

Understanding protocol implementation differences is essential for gateway redundancy administration.

Determine the CLI execution result.

Entering `standby 30 ip 10.30.0.2` on an interface already configured with physical IP

10.30.0.2

causes Cisco IOS to return a command syntax/validation error and reject the entry.

The CLI parser validates the virtual IP against existing interface address configurations immediately upon entry.

Key Concept

HSRP Virtual IP Address Assignment Restrictions

PreviousPage 3 / 3

First Hop Redundancy Protocols (HSRP and VRRP)

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