Question

Difficulty: MediumHigh Availability and Redundancy Concepts

A network administrator is designing a high-availability infrastructure for a datacenter rack connected to dual switches and redundant edge routers. The design must support link aggregation across physical network interfaces on dual-homed servers while also ensuring rapid Layer 3 gateway failover if an upstream WAN link drops. Which TWO of the following technical configurations should the administrator implement to meet these requirements?

  1. Configure Link Aggregation Control Protocol (LACP) in conjunction with multi-chassis or stacked switches to provide dual-homed NIC redundancy and combined link capacity.Answer
  2. Enable interface tracking and preemption within a First Hop Redundancy Protocol (FHRP) on the primary edge router to trigger gateway failover if the upstream uplink fails.Answer
  3. C
    Configure all host workstations with the physical IP address of the primary edge router interface as their default gateway address.
  4. D
    Set the Spanning Tree Protocol (STP) bridge priority to the maximum numerical value (61440) on the primary core switch to force it to become the Root Bridge.
  5. E
    Create static ARP table entries on host machines binding the FHRP Virtual IP to the primary router's physical MAC address to decrease convergence time.

Answer

The administrator should implement Link Aggregation Control Protocol (LACP) across stacked or multi-chassis switches for server NIC redundancy, and enable FHRP interface tracking with preemption on the edge routers for upstream-aware gateway failover.
Combining LACP across stackable/multi-chassis switches provides resilient, bandwidth-aggregated Layer 2 connections for servers. Paired with FHRP interface tracking and preemption on Layer 3 edge routers, the network achieves both switch link redundancy and dynamic gateway failover triggered by upstream connection drops.

Step-by-Step Solution

1
Identify the requirement for Layer 2 link aggregation and switch redundancy for dual-homed servers.
Selected LACP combined with switch stacking/MCLAG to bundle multiple physical interfaces into a logical link across separate physical switch chassis.
LACP provides dynamic link aggregation and fault tolerance, while switch stacking/MCLAG permits cross-switch link termination without creating Layer 2 loops.
2
Identify the requirement for upstream-aware Layer 3 gateway redundancy.
Selected FHRP interface tracking and preemption.
Interface tracking lowers the active router's priority upon WAN interface failure, and preemption allows the secondary router to take over the active Virtual IP (VIP) role dynamically.

Key Concept

Multi-Layer High Availability & FHRP Tracking
Estimated Time:1m 30s
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