Cisco Certified Network Associate (CCNA) Practice Exam

What metric is considered the most important in EIGRP routing decisions?

1. Delay

2. Reliability

3. Load

4. Bandwidth

The correct answer is: Bandwidth

In EIGRP (Enhanced Interior Gateway Routing Protocol), the most important metric in routing decisions is bandwidth. EIGRP uses a composite metric to determine the best path to a destination, which is calculated using several factors: bandwidth, delay, load, and reliability. However, bandwidth holds the highest significance in the metric calculation. The reason bandwidth is considered the most critical metric is that it directly impacts the capacity of the link to handle data traffic. When EIGRP evaluates multiple routes to reach the same destination, it first considers the bandwidth of the routes. A route with higher bandwidth is preferred because it can support higher data rates and provide better performance under load. While other metrics such as delay, reliability, and load are factored into the routing decision, they are secondary to bandwidth. For example, even if a link has low delay or high reliability, if its bandwidth is lower than an alternative path, EIGRP will still select the route with the higher bandwidth for optimal performance. This focus on bandwidth ensures efficient use of network resources and helps maintain high throughput.