First Hop Redundancy Protocols (HSRP and VRRP)

50 questions

Question 21Question

An administrator is configuring first-hop redundancy on router R1 for VLAN 50 using HSRPv2. Interface GigabitEthernet0/0/0 on R1 is assigned the IPv4 address 192.168.50.1/24192.168.50.1/24. The administrator enters interface configuration mode and issues the command `standby 50 ip 192.168.50.1` to establish the virtual IP address. Which outcome will result from this configuration attempt?

Show answer & explanation

Answer: The command line interface rejects the command because HSRP forbids assigning a router's physical interface IPv4 address as the virtual IP address.

Answer

The command line interface rejects the command because HSRP forbids assigning a router's physical interface IPv4 address as the virtual IP address.
In Cisco HSRP implementation, the virtual IPv4 address must be an unused IP address on the subnet segment. It cannot match the physical IP address assigned to any interface on any router participating in the HSRP group. Attempting to assign an existing physical IP address causes Cisco IOS to reject the `standby ip` command with a syntax validation error.

Step-by-Step Solution

1
Analyze the HSRP virtual IP assignment rule in Cisco IOS.
HSRP (both v1 and v2) mandates that the virtual IPv4 address must be an unassigned IP within the subnet segment, strictly distinct from any physical IP configured on participating routers.
Preventing IP overlaps ensures ARP resolution and virtual MAC binding operate without address conflicts.
2
Compare HSRP rules with VRRP rules regarding IP address ownership.
Unlike VRRP—where configuring the virtual IP to match a master router's physical IP address is allowed and automatically sets the VRRP priority to 255 (IP address owner)—HSRP does not support IP address ownership.
HSRP syntax validation rejects physical IP matches at CLI input time.
3
Determine the CLI outcome when `standby 50 ip 192.168.50.1` is entered on R1.
Cisco IOS generates an error message (such as `% Bad IP address` or `% Address on interface cannot be used as HSRP virtual IP`) and rejects the statement.
The input violates core HSRP validation rules.

Key Concept

HSRP Virtual IP Addressing vs VRRP IP Address Ownership
Estimated Time:1m 30s
Question 22Question

A network administrator is configuring HSRP on a router's GigabitEthernet0/0 interface, which has been assigned the physical IPv4 address 192.168.10.1/24192.168.10.1/24. The administrator enters the command `standby 1 ip 192.168.10.1` under the interface configuration mode. What issue does this configuration introduce?

Show answer & explanation

Answer: It configures the HSRP virtual IP address to match a physical interface IP address, which is invalid in HSRP.

Answer

Assigning the physical interface IPv4 address as the HSRP virtual IP address is an invalid configuration because HSRP requires the virtual IP to be a separate, distinct IP address within the subnet.
In Cisco Hot Standby Router Protocol (HSRP), the virtual IP address shared by the group must be a unique IP address on the local subnet that is not assigned to any router's physical interface. Attempting to assign a router's physical IP address as the HSRP virtual IP address is invalid and prevents proper operation.

Step-by-Step Solution

1
Identify the IP address assigned to the physical interface and the IP address specified in the `standby` command.
The physical interface IP address is 192.168.10.1192.168.10.1, and the command sets the virtual IP to 192.168.10.1192.168.10.1.
Comparing these addresses verifies whether the virtual IP collides with a physical IP.
2
Recall HSRP rules regarding virtual IP address assignment.
Unlike VRRP (which allows owning the IP address), HSRP requires the virtual IP address to be an unused IP address on the subnet, distinct from all router physical interface IPs in the group.
Enforces proper HSRP protocol behavior and prevents address duplicate conflicts.

Key Concept

HSRP Virtual IP Address Assignment Rules
Question 23Question

Which of the following statements correctly compare the default operational characteristics and parameters of HSRP (v1) and VRRP (v2)? (Select two.)

Select all that apply

Show answer & explanation

Answer: HSRPv1 uses virtual MAC addresses in the format 0000.0c07.acXX, whereas VRRPv2 uses the format 0000.5e00.01XX.; HSRP names the primary forwarding gateway the Active router, whereas VRRP names it the Master router.

Answer

The correct statements are that HSRPv1 uses virtual MAC addresses formatted as 0000.0c07.acXX while VRRPv2 uses 0000.5e00.01XX, and HSRP designates the forwarding router as Active while VRRP designates it as Master.
HSRPv1 and VRRPv2 differ in virtual MAC schemes (0000.0c07.acXX vs 0000.5e00.01XX) and role naming conventions (Active/Standby in HSRP vs Master/Backup in VRRP).

Step-by-Step Solution

1
Analyze virtual MAC address structure for both protocols
HSRPv1 uses standard MAC prefix 0000.0c07.ac followed by the group ID. VRRPv2 uses 0000.5e00.01 followed by the group ID.
Each protocol reserves a specific IEEE OID/MAC range for virtual gateway identification.
2
Compare role terminology between Cisco proprietary HSRP and open standard VRRP
HSRP uses Active/Standby roles, whereas VRRP uses Master/Backup roles.
Standardization differences lead to distinct terminology for equivalent primary/secondary forwarding roles.
3
Evaluate IP address assignment and preemption rules
VRRP supports using an interface's physical IP as the virtual IP address and enables preemption by default. HSRP requires a separate virtual IP address and disables preemption by default.
Differentiates implementation behavior between the two First Hop Redundancy Protocols.

Key Concept

HSRP and VRRP Operational Differences
Question 24Question

An enterprise router R1 is configured as the active HSRPv1 router for Group 10 with an initial priority of 110 and preemption enabled. R1 tracks its WAN uplink interface GigabitEthernet0/1 with a priority decrement value of 20. Router R2 is configured as the standby router for Group 10 with a priority of 100 and preemption enabled. Place the operational events in the exact chronological sequence following a line-protocol failure on R1's GigabitEthernet0/1 interface until failover convergence completes.

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Answer

The correct chronological sequence is: (1) R1 detects tracked interface failure -> (2) R1 decrements priority to 90 -> (3) R1 sends Hello with priority 90 -> (4) R2 compares priorities (100 vs 90) -> (5) R2 transmits an HSRP Coup message -> (6) R2 enters Active state and issues a Gratuitous ARP while R1 becomes Standby.
HSRP convergence follows a strict sequence when interface tracking degrades priority: detection of interface failure occurs first, leading to immediate priority calculation on the active router. The reduced priority is then advertised to the standby router via standard Hello messages. The standby router evaluates the lower priority, triggers preemption by sending a Coup message, assumes the Active state, and finally sends a Gratuitous ARP to re-align Layer 2 switch forwarding tables.

Step-by-Step Solution

1
Detect Link Failure
R1 detects line-protocol failure on GigabitEthernet0/1.
Interface tracking monitors the operational state of the configured interface.
2
Calculate Priority Decrement
R1's priority changes from 110 to 90.
The configured track action automatically subtracts 20 from R1's active priority (11020=90110 - 20 = 90).
3
Advertise New Priority
R1 sends an HSRP Hello packet containing priority 90.
HSRP routers communicate state changes via periodic Hello messages sent to 224.0.0.2.
4
Evaluate Preemption Criteria
R2 identifies that its priority (100) exceeds R1's reported priority (90).
With preemption configured, a standby router constantly compares received active priority against its own.
5
Signal Takeover
R2 sends an HSRP Coup message.
The Coup message informs the current active router that a higher-priority router is asserting control.
6
Final Convergence & Traffic Steering
R2 transitions to Active, issues a Gratuitous ARP for the virtual IP/MAC, and R1 steps down to Standby.
The Gratuitous ARP updates Layer 2 switch forwarding tables so host traffic is immediately steered to R2.

Key Concept

HSRP Interface Tracking and Preemption Mechanism
Question 25Question

A network engineer is configuring first-hop redundancy on router R1's GigabitEthernet0/1 interface, which has been assigned the physical IPv4 address 192.168.20.1/24192.168.20.1/24. The engineer initially attempts to configure HSRP Group 20 using the command `standby 20 ip 192.168.20.1`, but then evaluates migrating the design to VRRPv2 using the command `vrrp 20 ip 192.168.20.1`. Assuming default protocol parameters are used, which operational distinction correctly describes how HSRP and VRRP handle this configuration attempt and default preemption behavior?

Show answer & explanation

Answer: HSRP rejects configuring the virtual IP address to match a physical interface IP address, whereas VRRP permits it, automatically assigning a priority of 255 to the IP address owner with mandatory preemption enabled.

Answer

HSRP rejects configuring the virtual IP address to match a physical interface IP address, whereas VRRP permits it, automatically assigning a priority of 255 to the IP address owner with mandatory preemption enabled.
The correct answer accurately contrasts the Virtual IP assignment constraints and preemption defaults between Cisco HSRP and standard VRRP. HSRP mandates that the virtual IP address must be an unassigned, unique IP within the local subnet and will throw a configuration error if matched to a physical interface address. Furthermore, HSRP preemption is disabled by default. In contrast, VRRP allows the virtual IP address to be identical to a physical interface IP address on the router (making it the IP address owner with priority 255), and VRRP preemption is enabled by default.

Step-by-Step Solution

1
Evaluate HSRP Virtual IP assignment rules
HSRP requires the Virtual IP address to be a unique IP address within the subnet that is NOT assigned to any physical interface on participating routers.
Cisco IOS HSRP prevents IP address duplication on physical interfaces to prevent ARP and routing loop anomalies.
2
Evaluate VRRP Virtual IP assignment rules (IP Address Owner)
VRRP permits the virtual IP address to match the primary physical IPv4 address of an interface.
When a router's interface physical IP matches the VRRP virtual IP, that router acts as the VRRP IP Address Owner and is automatically assigned the maximum priority of 255.
3
Analyze default preemption behavior in HSRP versus VRRP
HSRP preemption is disabled by default, whereas VRRP preemption is enabled by default.
VRRP RFC standards mandate that preemption is enabled out-of-the-box, ensuring a higher priority router always assumes the Master role, especially when priority is 255.

Key Concept

First Hop Redundancy Protocol (FHRP) Virtual IP Assignment and Preemption Defaults
Estimated Time:2m 0s
Question 26Question

An network engineer is configuring HSRP group 15 on a Cisco router interface that has been assigned the primary IPv4 address 172.16.20.2/24172.16.20.2/24. Which requirement must be met when defining the HSRP virtual IPv4 address for this interface?

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Answer: The virtual IPv4 address must belong to the 172.16.20.0/24172.16.20.0/24 subnet and cannot match the physical IPv4 address of any router in the group.

Answer

The HSRP virtual IPv4 address must be in the same IPv4 subnet as the interface's physical IP address (172.16.20.0/24172.16.20.0/24), but it cannot be identical to the physical IPv4 address configured on any router participating in the HSRP group.
In HSRP (v1 and v2), the virtual IP address configured via the command `standby <group> ip <ip-address>` must reside within the same IP subnet as the router interface's physical IP address so local LAN clients can reach it as their default gateway. However, Cisco IOS explicitly blocks assigning a virtual IP address that matches any physical IP assigned to a router interface in the group.

Step-by-Step Solution

1
Identify the physical IP subnet of the interface.
The interface has IP address 172.16.20.2/24172.16.20.2/24, placing it in the 172.16.20.0/24172.16.20.0/24 subnet.
Default gateway traffic from LAN clients must be reachable within their local IP broadcast domain.
2
Apply the HSRP virtual IP assignment rule.
Select an unassigned IP address within 172.16.20.0/24172.16.20.0/24 (e.g., 172.16.20.1172.16.20.1).
Cisco HSRP requires virtual IP addresses to belong to the local subnet and strictly forbids reusing any physical interface IP address of HSRP routers.

Key Concept

HSRP Virtual IP Address Assignment Requirements
Question 27Question

Arrange the Cisco Hot Standby Router Protocol (HSRP) router states in the correct sequential order from initial interface startup to the active forwarding role.

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Answer

The correct sequence of HSRP state transitions from startup to active forwarding is: Initial state, Listen state, Speak state, Standby state, and Active state.
HSRP router state transitions follow a strict logical progression: Initial (startup), Listen (receives Hello packets), Speak (sends Hello packets and joins election), Standby (selected as candidate backup), and Active (forwards virtual IP traffic).

Step-by-Step Solution

1
Identify the initialization state.
The router starts in the Initial state.
An interface must be enabled and initialized before any protocol messages are processed.
2
Determine the discovery phase.
The router transitions to the Listen state.
In the Listen state, the router receives Hello packets from existing group members without sending its own.
3
Identify the election participation phase.
The router moves to the Speak state.
The router sends periodic Hello messages to compete for active or standby router roles.
4
Determine the backup role assignment.
The router enters the Standby state.
The router is designated as the candidate to take over if the active router fails.
5
Identify the primary forwarding role.
The router reaches the Active state.
The elected router actively forwards frames destined to the virtual MAC and virtual IP address.

Key Concept

HSRP Router State Machine Sequence
Question 28Question

A network administrator is evaluating the protocol mechanics and default operational behaviors of HSRPv2 and VRRPv2 across an enterprise distribution layer. Which two statements accurately describe the functional differences in preemption, virtual IP assignment, or virtual MAC addressing between HSRP and VRRP? (Select two.)

Select all that apply

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Answer: VRRP permits configuring the virtual IP address to match the physical IP address assigned to an interface, whereas HSRP requires the virtual IP address to be an unassigned address within the local subnet.; VRRP enables preemption by default for participating routers, whereas HSRP requires preemption to be explicitly configured on candidate standby routers.

Answer

The correct statements are that VRRP permits configuring the virtual IP address to match a physical IP address (IP address owner) while HSRP requires a unique IP, and VRRP enables preemption by default whereas HSRP requires explicit preemption configuration.
VRRP supports IP address ownership, allowing the virtual IP address to be identical to the primary physical IP address of an interface (which automatically assigns priority 255 to that router). HSRP does not support this and mandates that the virtual IP address must be an unused IP on the subnet. Additionally, VRRP preemption is enabled by default, whereas HSRP requires manual preemption configuration.

Step-by-Step Solution

1
Analyze virtual IP assignment rules for HSRP vs VRRP
VRRP supports IP address ownership where the Master router's physical interface IP is used as the virtual IP (priority becomes 255). HSRP requires the virtual IP to be a separate, distinct IP address not assigned to any physical interface in the subnet.
Determines the validity of virtual IP configuration options.
2
Analyze default preemption mechanics across both protocols
VRRP has preemption enabled by default with a default priority of 100. HSRP has preemption disabled by default, meaning a higher-priority router will not take over the Active role unless 'standby preempt' is explicitly configured.
Identifies procedural configuration differences for failover behavior.
3
Verify virtual MAC address allocations for HSRPv2 and VRRPv2
VRRPv2 uses 0000.5E00.01xx0000.5E00.01xx. HSRPv1 uses 0000.0C07.ACxx0000.0C07.ACxx, and HSRPv2 uses 0000.0C9F.Fxxx0000.0C9F.Fxxx.
Evaluates MAC range precision to rule out inverted options.

Key Concept

HSRP vs VRRP Operational & Architectural Comparison
Question 29Question

A network administrator is configuring Cisco HSRP group 5 on interface GigabitEthernet0/0 of a primary router. The interface is assigned the physical IPv4 address 10.1.10.2/24. When executing the command `standby 5 ip 10.1.10.2`, the router rejects the configuration. Which statement correctly explains why Cisco IOS rejects this command?

Show answer & explanation

Answer: HSRP requires the virtual IPv4 address to be unique and not match the physical IP address of any participating router interface.

Answer

HSRP requires the virtual IPv4 address to be unique and not match the physical IP address of any participating router interface.
In HSRP, the virtual IPv4 address shared by the redundancy group must be a unique IP address in the local subnet that is not assigned as the physical interface address of any member router. When a network administrator attempts to assign an existing physical IP as the HSRP virtual IP, Cisco IOS rejects the command.

Step-by-Step Solution

1
Analyze the HSRP virtual IP address configuration rule in Cisco IOS.
In HSRP (both v1 and v2), the virtual IP address must be a separate, unused IP address within the local primary IP subnet.
Cisco IOS explicitly blocks assigning a router's physical interface IP address as the HSRP virtual IP address to avoid ARP and routing conflicts.
2
Compare HSRP behavior with VRRP.
Unlike VRRP (which permits an IP Address Owner where the virtual IP matches the physical IP), HSRP rejects physical IP assignment.
Understanding protocol differences prevents misconfiguration errors on Cisco routers.

Key Concept

HSRP Virtual IP Address Assignment Rules
Question 30Question

A network administrator is evaluating First Hop Redundancy Protocols (FHRP) for deployment across campus gateways. Which two statements correctly describe default operational characteristics of HSRPv1 compared to VRRPv2?

Select all that apply

Show answer & explanation

Answer: VRRP enables router preemption by default, whereas HSRP requires preemption to be explicitly configured under interface settings.; HSRP designates redundancy roles as Active and Standby, whereas VRRP uses Master and Backup to define router states.

Answer

VRRP enables preemption by default while HSRP requires explicit preemption configuration, and HSRP uses Active/Standby role terminology while VRRP uses Master/Backup.
VRRP has preemption enabled by default and uses Master/Backup role terminology, whereas HSRP has preemption disabled by default and uses Active/Standby role terminology.

Step-by-Step Solution

1
Evaluate preemption default settings for HSRP and VRRP
VRRP preemption is enabled by default; HSRP preemption is disabled by default.
By protocol specification, VRRP automatically preempts lower-priority master routers unless preemption is manually disabled, whereas HSRP requires interface preemption syntax.
2
Examine operational role terminology across both protocols
HSRP uses Active and Standby; VRRP uses Master and Backup.
This aligns with RFC standards for VRRP compared to Cisco proprietary HSRP conventions.

Key Concept

First Hop Redundancy Protocols (HSRP and VRRP) default behavior comparison
Question 31Question

A network administrator is troubleshooting an intermittent first-hop gateway issue on a dual-homed router pair (R1R1 and R2R2) providing redundancy for VLAN 50 (172.20.50.0/24172.20.50.0/24). R1R1 is intended to be the active HSRP router under normal operational conditions.

The interface configurations are shown below:

text
R1# show running-config interface GigabitEthernet0/1
interface GigabitEthernet0/1
ip address 172.20.50.2 255.255.255.0
standby 50 ip 172.20.50.1
standby 50 priority 115
standby 50 track GigabitEthernet0/0 20

R2# show running-config interface GigabitEthernet0/1
interface GigabitEthernet0/1
ip address 172.20.50.3 255.255.255.0
standby 50 ip 172.20.50.1
standby 50 priority 105
standby 50 preempt

When the uplink interface GigabitEthernet0/0 on R1R1 fails, R1R1's priority drops from 115 to 95 (11520115 - 20), allowing R2R2 (priority 105, preemption enabled) to take over as the Active router. However, when GigabitEthernet0/0 on R1R1 recovers and its priority returns to 115, R2R2 remains the Active router and R1R1 stays in Standby state.

Which configuration change on R1R1 will resolve this issue so that R1R1 automatically reclaims the Active HSRP role upon link recovery?

Show answer & explanation

Answer: Configure standby 50 preempt under interface GigabitEthernet0/1 on R1.

Answer

Enabling preemption on R1 using the command 'standby 50 preempt' allows R1 to reclaim the Active gateway role after its tracked interface recovers.
By default, HSRP preemption is disabled. Even if a router has a higher priority than the current Active router, it will not attempt to take over the Active role unless preemption is explicitly configured using the 'standby <group> preempt' command. On R1, once its tracked interface recovered, its priority returned to 115 (higher than R2's 105), but because preemption was missing on R1, it remained in the Standby state. Adding 'standby 50 preempt' to R1 resolves the issue.

Step-by-Step Solution

1
Analyze initial HSRP priorities and roles
R1 has priority 115 and R2 has priority 105. R1 is Active.
Higher priority determines the Active HSRP router.
2
Evaluate failover behavior when R1's tracked interface fails
R1 priority drops to 95 (115 - 20). R2 has priority 105 and 'standby 50 preempt' enabled, so R2 takes over as Active.
R2 has preemption enabled and its priority (105) is now higher than R1's reduced priority (95).
3
Evaluate recovery behavior when R1's tracked interface comes back up
R1 priority returns to 115, but R1 remains Standby because it lacks the 'standby 50 preempt' command.
Without preemption explicitly configured, an HSRP router with a higher priority will not preempt an already operational Active router.
4
Determine the required configuration fix
Adding 'standby 50 preempt' to R1 allows it to preempt R2 (115 > 105) once priority is restored upon link recovery.
Preemption must be enabled on the router that needs to reclaim the Active state.

Key Concept

HSRP Preemption and Interface Tracking Mechanics
Question 32Question

A network engineer is implementing First Hop Redundancy Protocols (FHRP) across an enterprise distribution layer, deploying HSRPv2 on VLAN 10 and VRRPv3 on VLAN 20. Which two statements correctly describe the operational mechanics, protocol addresses, and default behavior differences between HSRPv2 and VRRPv3? (Select two.)

Select all that apply

Show answer & explanation

Answer: HSRPv2 sends hello messages to the multicast destination IPv4 address 224.0.0.102, whereas VRRPv3 sends advertisement packets to the multicast address 224.0.0.18 for IPv4 deployments.; VRRP allows the virtual IP address to match a physical IP address assigned to the Master router's interface, whereas HSRP requires the virtual IP to be unique and different from all physical interface IP addresses in the group.

Answer

HSRPv2 sends hello packets to multicast address 224.0.0.102 while VRRPv3 uses 224.0.0.18, and VRRP permits configuring a virtual IP that matches a physical interface IP while HSRP requires a unique virtual IP address.
The correct statements correctly identify the protocol multicast addresses (HSRPv2 uses 224.0.0.102, whereas VRRPv3 uses 224.0.0.18) and the virtual IP assignment rules (VRRP allows the virtual IP to match a physical interface IP, whereas HSRP mandates a unique virtual IP address).

Step-by-Step Solution

1
Analyze multicast destination addressing for HSRPv2 and VRRPv3.
HSRPv1 uses 224.0.0.2, HSRPv2 uses 224.0.0.102 (UDP 1985). VRRPv2 and VRRPv3 (IPv4) use 224.0.0.18 (IP protocol 112).
Correct protocol understanding requires knowing transport and network layer multicast identifiers.
2
Evaluate virtual IP address assignment constraints.
HSRP requires the virtual IP to be unique within the subnet and not assigned as a physical IP on any participating gateway interface. VRRP permits the virtual IP to be identical to the IP address configured on the Master router's physical interface (IP address owner).
This is a fundamental architectural difference between Cisco proprietary HSRP and standard VRRP.
3
Evaluate preemption defaults for both protocols.
HSRP preemption is disabled by default. VRRP preemption is enabled by default.
Default preemption rules dictate failover and recovery behavior when a higher-priority device comes online.

Key Concept

FHRP Protocol Differences (HSRP vs. VRRP Addressing, Virtual IP Rules, and Preemption Defaults)
Question 33Question

Place the Cisco Hot Standby Router Protocol (HSRP) router states in the correct sequential order from interface initialization to the state where the router assumes primary packet forwarding for the virtual gateway.

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Answer

The correct sequential order of HSRP router states is: Initial State, Listen State, Speak State, Standby State, and Active State.
When HSRP is enabled on an interface, the router progresses systematically through five main states: Initial (interface up), Listen (receives Hello packets to learn virtual IP and detect peers), Speak (transmits periodic Hello packets to enter active/standby election), Standby (elected backup router), and finally Active (elected primary gateway responsible for handling virtual IP traffic).

Step-by-Step Solution

1
Identify the state representing initial interface bring-up
Initial State is the starting point before any HSRP communication begins.
HSRP process initiates when the underlying Layer 3 interface comes up.
2
Identify the state where the router observes existing HSRP peers without transmitting
Listen State follows Initial State.
The router must first hear if active or standby routers already exist on the segment.
3
Determine when the router starts transmitting Hello packets to join the election
Speak State follows Listen State.
The router sends Hello packets to announce its presence and participate in role selection.
4
Identify the interim role prior to becoming the primary forwarder
Standby State follows Speak State.
The router acts as the designated backup router before assuming the active role if election parameters permit.
5
Identify the final operational state responsible for forwarding virtual IP traffic
Active State is the final state.
The elected active router answers ARP requests for the virtual IP and forwards user traffic.

Key Concept

HSRP State Machine Transitions
Question 34Question

A network administrator configures HSRP group 10 on two switches, R1 and R2, to provide gateway redundancy for VLAN 20. R1 is configured with a priority of 115, preemption enabled, and tracks interface GigabitEthernet0/1 with a priority decrement of 20. R2 is configured with a priority of 105, but preemption is disabled on R2. Initially, all interfaces are operational, and R1 is the Active router. If interface GigabitEthernet0/1 on R1 fails, which router will fulfill the Active role for HSRP group 10, and why?

Show answer & explanation

Answer: R1 remains the Active router because R2 does not have preemption enabled, even though R1's operational priority drops to 95.

Answer

R1 remains the Active router because preemption is not enabled on R2, preventing it from taking over despite having a higher operational priority.
In HSRP, when an active router's tracked interface fails, its priority is decremented (115 - 20 = 95). Even though the standby router has a higher priority (105 > 95), it cannot claim the Active role unless preemption ('standby preempt') is explicitly configured on the standby router itself. Therefore, the current Active router remains Active.

Step-by-Step Solution

1
Calculate R1's operational priority after the tracked interface failure.
Initial priority (115) minus decrement (20) equals operational priority 95.
Interface tracking reduces the active router's HSRP priority upon tracked link failure.
2
Compare the operational priorities of R1 and R2.
R1 operational priority is 95; R2 priority is 105.
R2 now possesses a higher numeric priority than R1.
3
Evaluate preemption settings on the standby router (R2).
R2 does not have preemption enabled.
In HSRP, a standby router with a higher priority will NOT seize the Active role from an existing Active router unless 'standby preempt' is explicitly configured on the standby router.

Key Concept

HSRP Preemption Mechanics and Interface Tracking
Question 35Question

A network administrator has configured HSRPv2 between two routers, R1 (Active, priority 110, interface tracking decrements priority by 30) and R2 (Standby, priority 100, preemption enabled). Arrange the operational steps in the correct chronological sequence from the moment R1's tracked interface fails until R2 successfully handles traffic as the new Active router.

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Answer

The correct chronological order is: 1) R1 detects tracked interface failure and reduces priority to 80; 2) R1 advertises the degraded priority via HSRP Hello; 3) R2 identifies its higher priority and sends an HSRP Coup message; 4) R1 relinquishes active status and broadcasts an HSRP Resign message; 5) R2 assumes the Active state and broadcasts a Gratuitous ARP to update switch CAM tables.
The failover process begins locally on R1 when the tracked link drops, causing priority degradation. Next, R1 informs the segment via Hello packets containing the updated priority. R2 evaluates this priority against its own higher priority and uses its preemption configuration to send a Coup message. R1 acknowledges this by relinquishing control and issuing a Resign message while moving to Standby state. Finally, R2 assumes the Active state and broadcasts a Gratuitous ARP to rewrite switch port bindings for the shared virtual MAC address.

Step-by-Step Solution

1
Identify the initial triggering event
R1's tracked interface drops, reducing R1's priority from 110 to 80.
HSRP interface tracking dynamically recalculates priority immediately upon physical link or line protocol failure.
2
Determine how priority changes are communicated
R1 transmits Hello packets advertising priority 80.
HSRP routers exchange control messages periodically to communicate current group state and priority values.
3
Analyze preemption logic on the standby device
R2 observes R1's priority (80) is lower than R2's (100) and sends a Coup packet.
Preemption allows a router with higher priority than the current Active router to claim the Active role.
4
Trace active router role surrender
R1 transitions to Standby after issuing a Resign packet.
Receiving a valid Coup from a higher-priority router forces the current Active router to yield leadership.
5
Verify Layer 2 forwarding convergence
R2 moves to Active state and emits a Gratuitous ARP.
GARP ensures attached Layer 2 switches immediately rewrite their MAC tables so traffic sent to the virtual IP/MAC reaches R2.

Key Concept

HSRP Preemption and Interface Tracking Convergence Sequence
Question 36Question

Which two statements accurately describe the default operational characteristics of Cisco Hot Standby Router Protocol version 1 (HSRPv1)? (Select two.)

Select all that apply

Show answer & explanation

Answer: Preemption is disabled by default on HSRP-enabled interfaces.; The default interface priority assigned to an HSRP group member is 100.

Answer

Preemption is disabled by default on HSRP-enabled interfaces, and the default interface priority assigned to an HSRP group member is 100.
The correct options accurately identify default HSRP behavior: preemption is disabled by default so a higher-priority router does not automatically assume the active role, and the default interface priority value is 100.

Step-by-Step Solution

1
Evaluate default HSRP priority settings
Confirm that Cisco IOS assigns a default priority of 100 to HSRP group interfaces.
Priorities range from 0 to 255, with 100 being the baseline default.
2
Evaluate default HSRP preemption behavior
Confirm that preemption is disabled by default in HSRP.
Without the standby preempt command, a newly booted or recovered router with a higher priority remains in Standby state.
3
Verify virtual IP rules and tie-breaking logic
Identify incorrect statements regarding physical IP reuse and tie-breaker rules.
HSRP virtual IPs must not equal physical interface IPs, and tie-breakers favor the highest IP address.

Key Concept

HSRP Default Operational Parameters and Preemption Mechanics
Question 37Question

A network operations engineer is migrating a dual-core distribution block from VRRPv2 to HSRPv2. During the migration on Switch-1 (interface VLAN 50, IPv4 address 10.50.1.1/24), the engineer attempts to assign 10.50.1.1 as the HSRP virtual IP address using the command `standby 50 ip 10.50.1.1`. The IOS XE CLI immediately returns an error and rejects the configuration. Which statement correctly explains the protocol design difference causing this failure?

Show answer & explanation

Answer: HSRP requires the virtual IP address to be an unassigned IP address within the subnet, whereas VRRP allows a router interface physical IP address to serve as the virtual IP address.

Answer

HSRP requires the virtual IP address to be an unassigned IP address within the subnet, whereas VRRP allows a router interface physical IP address to serve as the virtual IP address.
In HSRP, the virtual IP address must be a distinct, unassigned address within the IP subnet shared by the participating routers. VRRP supports IP address ownership (where the virtual IP matches a physical interface IP address and gives that router priority 255), but HSRP strictly disallows assigning a router's physical interface IP address as the HSRP virtual IP address.

Step-by-Step Solution

1
Analyze the operational rules for Cisco HSRP virtual IP address configuration.
HSRP (v1 and v2) mandates that the configured virtual IP address must be a unique, unassigned IP address within the local primary subnet and cannot match the physical IP address of any participating router interface.
Preventing IP overlap ensures standard ARP/ICMP processing and prevents local interface address conflicts in HSRP state machines.
2
Compare HSRP behavior with VRRP IP address ownership functionality.
VRRP permits the IP address owner scenario where the virtual IP matches the physical IP address of an interface on the Master router (setting priority automatically to 255).
This key design difference explains why a configuration valid in VRRP fails when replicated directly in HSRP.

Key Concept

First Hop Redundancy Protocols (HSRP vs. VRRP Virtual IP Assignment Rules)
Question 38Question

A network administrator is evaluating protocol mechanics between HSRPv2 and VRRPv3 for deployment across an enterprise distribution block. Which two operational statements regarding virtual IP assignment, multicast transport, and protocol behaviors are accurate? (Select two.)

Select all that apply

Show answer & explanation

Answer: VRRP permits the virtual IPv4 address to be identical to the physical IPv4 address assigned to the Master router's interface, whereas HSRP requires the virtual IP address to be unique and distinct from any physical IPv4 address assigned to participating routers.; HSRPv2 transmits hello packets using UDP port 1985 to multicast IPv4 address 224.0.0.102, whereas VRRPv3 encapsulation uses IP protocol number 112 destined to multicast IPv4 address 224.0.0.18.

Answer

The two correct statements are: (1) VRRP permits the virtual IPv4 address to match the physical interface IP of the master router while HSRP requires a distinct virtual IP address, and (2) HSRPv2 uses UDP port 1985 with destination multicast 224.0.0.102, whereas VRRPv3 uses IP protocol 112 with destination multicast 224.0.0.18.
VRRP allows IP address ownership (where the virtual IP is identical to the physical IP address of the master interface), while HSRP requires the virtual IP to be a distinct IP address on the subnet. Additionally, HSRPv2 uses UDP port 1985 to multicast 224.0.0.102, whereas VRRPv3 operates over IP protocol 112 to multicast 224.0.0.18.

Step-by-Step Solution

1
Analyze virtual IP address assignment rules for HSRP vs VRRP.
VRRP supports IP address ownership where the virtual IP matches the master router's physical IP address (priority set to 255 automatically). HSRP requires the virtual IP to be an unassigned IP on the subnet, distinct from all participating routers' physical IPs.
Understanding IP address assignment mechanics prevents configuration errors during FHRP deployment.
2
Examine transport protocol encapsulation and multicast addresses.
HSRPv2 uses UDP port 1985 and multicast 224.0.0.102. VRRPv3 uses IP protocol 112 directly (no transport header like UDP/TCP) and multicast 224.0.0.18.
Differentiating transport mechanics is essential for access control list (ACL) and firewall configuration.
3
Evaluate default preemption behavior differences.
HSRP disables preemption by default, whereas VRRP enables preemption by default.
Recognizing default preemption behaviors avoids unexpected routing mastership shifts.

Key Concept

HSRPv2 vs VRRPv3 protocol characteristics, transport mechanisms, preemption defaults, and virtual IP allocation rules
Question 39Question

An engineer is troubleshooting a first-hop redundancy deployment on a Cisco router interface configured with IPv4 address 192.168.100.1/24. When entering the command `standby 1 ip 192.168.100.1`, the CLI outputs `% HSRP: Bad IP address 192.168.100.1`. However, on a neighboring router running VRRP, assigning the physical interface IP address as the virtual IP address is accepted and functions correctly. What fundamental operational difference between HSRP and VRRP causes this behavioral discrepancy?

Show answer & explanation

Answer: HSRP mandates that the virtual IP address must be unique and cannot match any physical interface IP in the standby group, whereas VRRP supports IP address ownership where the master router physical IP serves as the virtual IP.

Answer

HSRP mandates that the virtual IP address must be unique and cannot match any physical interface IP in the standby group, whereas VRRP supports IP address ownership where the master router physical IP serves as the virtual IP.
In HSRP protocol operations, the virtual IP address MUST be distinct from any physical IPv4 address assigned to the interfaces participating in the HSRP group. Attempting to assign the physical interface IP as the HSRP virtual IP results in a CLI validation error (`% HSRP: Bad IP address`). Conversely, VRRP (RFC 3768 / RFC 5798) explicitly permits IP address ownership, allowing the physical interface IP of the master router to function as the virtual gateway IP address (setting the router priority to 255).

Step-by-Step Solution

1
Analyze the CLI error output: `% HSRP: Bad IP address 192.168.100.1`.
Identify that the Cisco IOS CLI rejects HSRP configuration when attempting to set the virtual IP equal to the physical interface IP.
Cisco HSRP (both version 1 and version 2) requires the virtual IP to be a separate, unique IPv4 address within the same subnet, distinct from all physical interface IPs assigned to participating routers.
2
Compare HSRP rules with VRRP rules regarding Virtual IP assignment.
Recognize that VRRP allows IP address ownership (where the Virtual IP address matches the physical interface IP address of the Master router).
When a VRRP router owns the IP address, its priority is automatically elevated to 255, making it the VRRP Master.
3
Evaluate the option choices to select the statement accurately explaining this architectural difference.
Select the statement highlighting that HSRP requires a unique virtual IP while VRRP supports IP address ownership.
This correctly identifies why HSRP produced an error while VRRP accepted the physical IP address.

Key Concept

HSRP vs. VRRP Virtual IP Address Ownership and Assignment Rules
Estimated Time:1m 30s
Question 40Question

A network administrator is designing a high-availability default gateway architecture for VLAN 10 (subnet 10.1.10.0/24) using two Layer 3 distribution switches. Switch-1 is configured with physical interface IP address 10.1.10.2/24 and Switch-2 is configured with physical interface IP address 10.1.10.3/24. The administrator is evaluating protocol characteristics between HSRPv2 and VRRPv3. Which two statements correctly describe operational differences and IP addressing rules between these protocols? (Select two.)

Select all that apply

Show answer & explanation

Answer: VRRPv3 allows the virtual IP address to match Switch-1's physical interface IP address (10.1.10.2), automatically designating Switch-1 as the IP address owner with a default priority of 255.; HSRPv2 sends control messages to the IPv4 multicast destination address 224.0.0.102, whereas VRRP (v2/v3) sends advertisement messages to the IPv4 multicast destination address 224.0.0.18.

Answer

The two correct statements are: VRRPv3 allows the virtual IP address to match a physical interface IP address (designating that router as the IP address owner with priority 255), and HSRPv2 uses multicast destination 224.0.0.102 while VRRP uses 224.0.0.18.
VRRPv3 supports IP address ownership where the virtual IP address matches a router's physical interface IP address, automatically elevating its priority to 255 (the maximum). In addition, HSRPv2 uses multicast group address 224.0.0.102 for hello packets, while VRRP uses multicast address 224.0.0.18.

Step-by-Step Solution

1
Analyze virtual IP assignment rules for HSRP vs VRRP
HSRP requires the virtual IP address to be distinct from all physical interface IP addresses assigned to routers in the group. VRRP allows IP address ownership, where the virtual IP matches a physical interface IP address and sets priority to 255.
Verifies whether IP ownership is supported in HSRP vs VRRP.
2
Verify multicast destination addresses for HSRPv2 and VRRP
HSRPv1 uses 224.0.0.2, HSRPv2 uses 224.0.0.102, and VRRP (both v2 and v3) uses 224.0.0.18.
Differentiates protocol transport mechanics across FHRP implementations.
3
Evaluate default preemption mechanisms
HSRP disables preemption by default (higher priority standby router will not take over active state without explicit configuration). VRRP enables preemption by default.
Eliminates incorrect claims regarding preemption defaults.

Key Concept

FHRP protocol differences: VRRP IP address ownership, HSRP virtual IP uniqueness requirements, protocol multicast addresses, and default preemption settings.
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First Hop Redundancy Protocols (HSRP and VRRP) Practice Questions — Cisco CCNA — Page 2 | Examkin