mediumMultiple Choice
300-410 Variance Practice Question
Consider the following EIGRP configuration on Router R4:
router eigrp 300
variance 2
network 172.16.0.0
What is the purpose of the variance command?
⚠ Common exam trap
Cisco often tests the distinction between 'variance' (which enables unequal-cost load balancing) and 'maximum-paths' (which limits the number of paths), leading candidates to mistakenly think variance controls the number of paths.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
It allows load balancing over paths with metrics up to twice the best metric.
The variance command in EIGRP allows unequal-cost load balancing by instructing the router to include routes in the routing table whose metric is less than or equal to the best metric multiplied by the variance value. With variance 2, any feasible successor route with a metric up to twice the best metric (i.e., ≤ best_metric × 2) will be installed and used for load balancing, provided it satisfies the feasibility condition (reported distance < feasible distance). Only option B accurately describes this behavior; option C is tempting but less precise because unequal-cost load balancing also requires feasible successors.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
It sets the maximum number of equal-cost paths to 2.
Why it's wrong here
Variance multiplies the feasible distance to admit unequal-cost paths into the local RIB; it does not cap equal-cost paths. Maximum-path controls that limit. Variance is tempting when you want load sharing across links of differing bandwidth, where it genuinely applies.
- ✓
It allows load balancing over paths with metrics up to twice the best metric.
Why this is correct
EIGRP variance multiplies the feasible successor's metric against the successor's metric; a value of 2 permits unequal-cost paths whose metric is no more than twice the best metric to be installed, enabling load balancing across them.
- ✗
It enables unequal-cost load balancing with a factor of 2.
Why it's wrong here
Variance sets the feasibility multiplier for EIGRP feasible successor routes, but load balancing also requires the maximum-paths value to exceed one; with the default of four, variance 2 alone does not guarantee balancing across two paths. It is tempting because variance does control unequal-cost balancing ratios.
- ✗
It sets the EIGRP metric weight for delay to 2.
Why it's wrong here
Variance controls feasible successor selection by allowing routes with metrics up to the specified multiple of the successor's metric into the local routing table; it has no effect on metric weights. It is tempting because both involve numeric multipliers, but delay weighting is set with the metric weights command.
Quick reference
Routing Protocol Comparison
| Protocol | Metric | Max Hops | Algorithm | Type |
|---|---|---|---|---|
| RIP v2 | Hop count | 15 | Bellman-Ford | Distance vector |
| OSPF | Cost (bandwidth) | Unlimited | Dijkstra (SPF) | Link state |
| EIGRP | Composite metric | Unlimited | DUAL | Hybrid |
| IS-IS | Cost | Unlimited | Dijkstra | Link state |
| BGP | Policy / attributes | Unlimited | Path vector | Path vector |
RIP's 15-hop limit makes it unsuitable for large networks. OSPF and EIGRP dominate modern enterprise deployments.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 300-410 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 300-410 exam.