Question

Difficulty: MediumHigh Availability and Redundancy Concepts

A network technician is auditing a campus network layout where two Layer 3 switches operate as redundant gateways for a corporate VLAN. Users report degraded throughput during high-traffic periods, and analysis reveals that traffic regularly traverses the inter-switch trunk link to reach the active gateway. Which TWO configuration steps should the technician verify or implement to ensure optimal high-availability traffic paths and prevent unnecessary trunk saturation? (Select TWO.)

  1. Configure the active Virtual Router Redundancy Protocol (VRRP) master switch to be the Spanning Tree Protocol (STP) root bridge for that VLAN.Answer
  2. Configure DHCP scope options to distribute the virtual IP (VIP) address as the default gateway for client workstations on the VLAN.Answer
  3. C
    Set the Spanning Tree Protocol (STP) bridge priority on the primary VRRP switch to the maximum numerical value of 61440.
  4. D
    Configure host network interface cards with the physical IP address of the primary switch as their default gateway.
  5. E
    Assign duplicate physical IP addresses to the redundant physical interfaces on both Layer 3 switches.

Answer

To optimize high-availability traffic flow and eliminate extra trunk hops, the primary VRRP switch must also be configured as the STP root bridge for the VLAN, and client devices must be assigned the virtual IP (VIP) address as their default gateway.
Optimal network redundancy relies on aligning Layer 2 topology with Layer 3 active forwarding paths. Ensuring that the VRRP master switch is also the Spanning Tree Protocol root bridge guarantees that switch ports leading to the active gateway remain in a forwarding state without unnecessary forwarding across inter-switch links. Furthermore, client devices must use the virtual IP address to benefit from automated gateway redundancy.

Step-by-Step Solution

1
Analyze the Layer 2 and Layer 3 topologies for high availability efficiency.
Identify that if the STP root bridge and the VRRP master gateway reside on different physical switches, client traffic will travel across the inter-switch link to reach the root bridge before being forwarded to the default gateway.
Aligning the STP root bridge position with the active FHRP master prevents asymmetrical paths and unnecessary utilization of inter-switch trunks.
2
Verify client default gateway configuration settings.
Ensure client workstations receive the shared Virtual IP (VIP) address from DHCP rather than the physical IP address of a single switch.
Using the VIP enables seamless hardware address failover without requiring client reconfiguration when the primary master fails.

Key Concept

First Hop Redundancy Protocol (FHRP) and Spanning Tree Protocol (STP) Coexistence
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