Which FHRP Prevents Single Router Failure in a Multi-Vendor Network?
After experiencing traffic disruptions from the failure of a single router, a customer asks an engineer to design a solution that will prevent this from occurring in the future. While examining the customer's environment, the engineer discovers that the routers are manufactured by a variety of different vendors, and they have varying amounts of CPU and memory resources. Additionally, several of the customer's applications require the ability to fine-tune the load-balancing parameters between multiple gateway routers. Which solution should be used to meet these requirements?
Community Votes
75% of anonymous learners picked answer A. Votes are pick records left by other test-takers — they are not the verified answer.
Community Insight
The question tests matching an FHRP to a heterogeneous, multi-vendor router environment; the trap is reaching for GLBP because it advertises the richest configurable load balancing, even though it is Cisco-proprietary.
A customer needs gateway redundancy across routers from several different vendors while still tuning load sharing between them, which points to VRRP as the correct first-hop redundancy protocol. This page explains why the open-standard VRRP (A) satisfies both the multi-vendor and the load-balancing requirements, and why HSRP and GLBP cannot.
Choosing GLBP (D) because it offers weighted, host-dependent and round-robin load balancing with tunable parameters — but GLBP only runs on Cisco devices, so it fails the requirement that routers from a variety of vendors participate.
Community Discussion (4 comments)
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Expert Analysis
Why the Answer Is Correct
VRRP (Virtual Router Redundancy Protocol) is an IETF open standard (RFC 3768 / RFC 5798) rather than a single-vendor feature, so it can be deployed across the customer's mix of routers from different manufacturers — this directly answers the "variety of different vendors" constraint. VRRP protects against the exact failure described: if the master router dies, the highest-priority backup takes over the virtual IP and MAC, so the single-router outage no longer disrupts traffic. The "fine-tune the load-balancing parameters" requirement is met by running multiple VRRP groups on the same physical interfaces with different priorities and, on some platforms, weighted tracking, so different subnets or flows prefer different gateways and traffic is shared rather than pinned to one device. Because VRRP is lightweight and standardized, it also tolerates the varying CPU and memory profiles of the mixed router fleet far better than a feature that depends on a single vendor's hardware.
Why the Other Options Are Wrong
HSRP (C) is Cisco-proprietary and, in its classic form, uses an active/standby model with a single active forwarder, so it neither spans a multi-vendor fleet nor provides the fine-grained per-group load balancing the applications want. GLBP (D) is the most tempting distractor because it does offer configurable load balancing — weighted, host-dependent and round-robin — but it is also Cisco-proprietary, so it cannot be the design choice when the routers come from various vendors and have different resource profiles. FHRP (B) is not a solution at all: it is the umbrella term for the family (VRRP, HSRP, GLBP), so selecting it does not name a deployable protocol. Note too that HSRP and GLBP, being Cisco-only, would force the customer to replace or standardize hardware, which is outside the stated requirements.
Community Comment Notes
As k3rnelpanicpj put it, "VRRP is only vendor neutral and has option for loadbalancing", which captures the two-part test this question applies. CoAsT_x reinforced the elimination logic bluntly: "GLBP is absolutely a Cisco proprietary protocol." Wasamela argued for GLBP on the grounds that it is vendor neutral and scales in heterogeneous environments, but that premise is factually inverted — GLBP is Cisco-proprietary, which is exactly why it fails here. The nmacc comment quoting GLBP documentation about using several default gateways and configuring load distribution describes a real GLBP capability, yet it still assumes an all-Cisco topology, so it does not override the multi-vendor requirement. The vote split (roughly 75/25 toward VRRP) aligns with the technical reading.
Official Reference
Exam Strategy
When a stem mentions routers or switches "from a variety of vendors," immediately eliminate every proprietary answer (HSRP, GLBP, and vendor-specific features) before evaluating the remaining options. Then check the second requirement — here, tunable load balancing — and confirm the open-standard protocol can still deliver it, which VRRP does through multiple groups and priorities.
Frequently Asked Questions
Why is GLBP wrong if it offers configurable load balancing?
GLBP is Cisco-proprietary, so it cannot run on the customer's routers from a variety of vendors. VRRP is the open-standard option that still supports tunable load sharing via multiple groups.
Why isn't FHRP the answer to this design question?
FHRP is only the generic family name for VRRP, HSRP and GLBP, not a protocol you configure. The question asks which solution to deploy, so the specific standard-based protocol is required.