ACSP Virtual Router Redundancy (VRRP) 5 — Questions and Answers
Question 1: When the VRRP master's tracked uplink fails and its priority drops below a backup router's priority, what must be enabled for the backup to take over?
- Object tracking must be enabled on the backup as well
- Preemption must be enabled on the backup router (Correct answer)
- The backup must have a static route pointing to the virtual IP
- VRRP authentication must be disabled
Correct answer: Preemption must be enabled on the backup router
Even with object tracking causing the master's priority to fall, the backup router will only preempt if preemption is enabled on that backup.
Question 2: What distinguishes an 'accept mode' configuration in VRRPv3 on Aruba switches?
- The master accepts routing updates from backup routers
- Non-IP-owner master routers accept and respond to packets destined for the virtual IP (Correct answer)
- Backup routers accept advertisement packets from any source
- The switch accepts VRRP configuration changes without a reload
Correct answer: Non-IP-owner master routers accept and respond to packets destined for the virtual IP
In accept mode, a VRRP master that does not own the virtual IP (non-owner) will still accept and process packets destined for the virtual IP address.
Question 3: Which of the following scenarios would cause a VRRP backup to NOT preempt the current master even though the backup has a higher priority?
- The backup's advertisement interval is set to 2 seconds
- Preemption is disabled on the backup router
- The master is the IP address owner with priority 255
- Both A and B (Correct answer)
Correct answer: Both A and B
A backup will not preempt if preemption is disabled on that router OR if the current master is the IP address owner (priority 255), which cannot be preempted.
Question 4: In a VRRP deployment, two routers share VRID 5 on VLAN 30. Router A (priority 150) is master. An administrator lowers Router A's priority to 80 via CLI without a reload. Router B has priority 100 and preemption enabled. What occurs?
- Nothing changes until Router A fails
- Router B immediately preempts and becomes master (Correct answer)
- A new election is triggered and the higher IP wins
- Both routers enter backup state and the group is temporarily unavailable
Correct answer: Router B immediately preempts and becomes master
When Router A's priority drops below Router B's 100, Router B detects the lower-priority advertisement and preempts to become master since preemption is enabled.
Question 5: What is the purpose of configuring a 'preemption delay' in VRRP on Aruba switches?
- To delay sending advertisements after a topology change
- To allow a higher-priority router time to populate its routing table before taking the master role (Correct answer)
- To prevent the master from responding to ARP until it is stable
- To synchronize advertisement intervals between master and backup
Correct answer: To allow a higher-priority router time to populate its routing table before taking the master role
Preemption delay gives the preempting router time to converge its routing table or STP topology before it takes over as the active gateway, preventing traffic blackholes.
Question 6: In an Aruba VRRP setup with three routers in the same group (priorities 150, 120, 100), which router becomes the new master if the current master (150) fails?
- The router with priority 100, as it has the longest uptime
- The router with priority 120, as it is the next highest priority (Correct answer)
- Both routers with 120 and 100 enter an election based on IP address
- The router with the lowest IP address in the group
Correct answer: The router with priority 120, as it is the next highest priority
VRRP selects the backup with the highest priority as the new master; with the 150-priority router gone, the 120-priority router wins the election.
Question 7: Which VRRP state is a router in when it is actively forwarding traffic on behalf of the virtual router?
- Initialize
- Backup
- Master (Correct answer)
- Active
Correct answer: Master
The Master state is the active forwarding state in VRRP; only the master router forwards traffic for the virtual IP and responds to ARP requests.
ACSP Virtual Router Redundancy (VRRP) 5
When the VRRP master's tracked uplink fails and its priority drops below a backup router's priority, what must be enabled for the backup to take over?