Lab Simulation 4 Guidelines This is a lab item in which tasks will be performed on virtual devices. - Refer to the Tasks tab to view the tasks for this lab item. - Refer to the Topology tab to access

VRRP Lab Simulation - Thorough Explanation --- Overall Goal The goal is first-hop redundancy: hosts on VLAN 100 (connected via ACCESS-SW1) need a reliable default gateway. Instead of pointing to a single physical switch (which becomes a single point of failure), both distribution

Submitted by brentm· Mar 6, 2026Infrastructure

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Lab Simulation 4 Guidelines This is a lab item in which tasks will be performed on virtual devices. - Refer to the Tasks tab to view the tasks for this lab item. - Refer to the Topology tab to access the device console(s) and perform the tasks. - Console access is available for all required devices by clicking the device icon or using the tab(s) above the console window. - All necessary preconfigurations have been applied. - Do not change the enable password or hostname for any device. - Save your configurations to NVRAM before moving to the next item. - Click Next at the bottom of the screen to submit this lab and move to the next question. - When Next is clicked, the lab closes and cannot be reopened. Topology Tasks Implement VRRP between DISTRO-SW1 and DISTRO-SW2 on VLAN100 for hosts connected to ACCESS-SW1 to achieve these goals: 1. Configure group number 200 using the virtual IP address of 192.168.1.200/24. 2. Configure DISTRO-SW1 as the active router using a priority value of 200 and DISTRO-SW2 as the standby router. 3. DISTRO-SW1 and DISTRO-SW2 should exchange VRRP hello packets every 20 seconds. Answer: Notice that the VRRP configuration in this sim is configured under interface VLAN, not physical interfaces. On DSW1: DSW1(config)#interface vlan 100 //The VLAN number may be different in the exam DSW1(config-if)#vrrp 200 ip 192.168.1.200 //virtual VRRP IP address, same on both switches, the IP address may be different in the exam DSW1(config-if)#vrrp 200 priority 200 //priority value may be different DSW1(config-if)#vrrp 200 timers advertise 20 //Specifying interval to 20 seconds On DSW2: DSW2(config)#interface vlan 100 DSW2(config-if)#vrrp 200 ip 192.168.1.200 DSW2(config-if)#vrrp 200 timers advertise 20 //Specifying interval to 20 seconds Verification DSW1,DSW2#show vrrp Save the configuration DSW1,DSW2#copy running-config startup-config

Explanation

VRRP Lab Simulation - Thorough Explanation

Overall Goal

The goal is first-hop redundancy: hosts on VLAN 100 (connected via ACCESS-SW1) need a reliable default gateway. Instead of pointing to a single physical switch (which becomes a single point of failure), both distribution switches share a virtual IP address via VRRP. If DISTRO-SW1 fails, DISTRO-SW2 automatically takes over - transparently, without hosts reconfiguring anything.

VRRP (Virtual Router Redundancy Protocol) is Cisco-compatible with open-standard routers, unlike HSRP (Cisco proprietary). The terminology differs: VRRP calls the primary the master (not "active"), and the backup the backup (not "standby") - though Cisco documentation and exams sometimes use "active/standby" loosely.

Why VLAN Interface, Not Physical Interface

VRRP is configured on SVI (Switched Virtual Interface) - interface vlan 100 - because that's the Layer 3 gateway interface for VLAN 100 traffic. Physical interfaces carry the trunk; the SVI is what hosts actually route through. Configuring VRRP on a physical port here would be wrong and non-functional.

Step-by-Step Reasoning

Steps 1-2: Access DSW1 console, enter interface vlan 100

You must be in interface config mode for the correct SVI. VRRP is applied per-interface. If you configure the wrong VLAN interface, hosts on VLAN 100 get no redundancy.

Step 3: vrrp 200 ip 192.168.1.200

200 is the VRRP group number - it ties the two switches together as peers. Both switches must use the same group number or they won't recognize each other.
192.168.1.200 is the virtual IP - this is what hosts use as their default gateway. It must match exactly on both switches.
This single command enables VRRP on the interface for this group.

If skipped: No virtual gateway exists. Hosts have no redundancy target.

Step 4: vrrp 200 priority 200 (DSW1 only)

Default VRRP priority is 100. By setting DSW1 to 200, it becomes the master router (higher priority wins). DSW2 is left at default (100), making it the backup automatically - no explicit "standby" command needed.

If skipped on DSW1: Both switches default to priority 100. VRRP will elect a master by IP address as a tiebreaker, which is non-deterministic and likely not what's intended. DSW1 may or may not become master.

If accidentally set on DSW2: DSW2 would compete for or win mastership, reversing your intent.

Step 5: vrrp 200 timers advertise 20 (DSW1)

VRRP master sends advertisement (hello) packets to inform the backup it's still alive. Default is 1 second. Setting it to 20 seconds means the master announces itself every 20 seconds.

If skipped: Timers default to 1 second, which contradicts the lab requirement. The backup also infers its dead-interval from the master's advertise timer, so mismatched timers can cause unnecessary failovers.

Steps 6-8: DSW2 - interface vlan 100, vrrp 200 ip 192.168.1.200

DSW2 must join the same VRRP group with the same virtual IP. The virtual IP must be identical - any mismatch means the two switches are in separate VRRP groups and provide no redundancy to each other.

If skipped entirely: DSW1 has no backup. Single point of failure remains.

Step 9: vrrp 200 timers advertise 20 (DSW2)

Both routers should agree on the advertise interval. In VRRP, the backup can learn the interval dynamically from the master's advertisements, but best practice is to configure it explicitly on both sides to ensure consistency and avoid version/implementation mismatch issues.

If skipped: May work due to dynamic learning, but exam graders typically check explicit configuration on both devices.

Step 10: show vrrp

Verification confirms:

Group 200 is listed
DSW1 shows State: Master, DSW2 shows State: Backup
Virtual IP is correct
Advertise interval is 20 seconds

If skipped: You won't catch misconfiguration before submitting. A typo in the virtual IP or wrong priority would go unnoticed.

Step 11: copy running-config startup-config

Saves config to NVRAM. Without this, a device reload loses all your work. The lab explicitly requires this before clicking Next.

If skipped: Config is lost on reboot; the lab may grade it as incomplete.

What Goes Wrong Out of Order

Scenario	Result
Configure priority before `vrrp X ip`	Command may be rejected - VRRP group must exist first
Set virtual IP differently on each switch	Switches form separate groups; no redundancy
Skip priority on DSW1	Election is non-deterministic; DSW2 could become master
Skip timer on DSW2	May work via dynamic learning, but not explicitly configured
Forget to save	Config lost on reload; lab graded as failed

Memory Tip

Think of it as "IP -> Priority -> Timer" on the master, then "IP -> Timer" on the backup:

"Both need the IP. Only the master needs the priority. Both need the timer."

Group number = 200, priority = 200 - in this lab they match, which makes it easy to remember: "200 everything on DSW1."

Topics

#VRRP#First Hop Redundancy Protocols (FHRP)#High Availability#Layer 3 Switching

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