Final answer:
EIGRP uses bandwidth and delay as the default metrics to calculate the best path to a destination. Load and reliability can be included optionally, but they are not enabled by default.
Step-by-step explanation:
EIGRP (Enhanced Interior Gateway Routing Protocol) uses various metrics by default to determine the best path to a destination network. The default metrics used by this advanced distance-vector routing protocol include:
- Bandwidth
- Delay
- Load
- Reliability
However, out of these metrics, bandwidth and delay are the primary factors EIGRP considers under default configurations. Load and reliability can be used, but they are typically not enabled by default, as they can lead to rapid changes in routing decisions and increased protocol traffic. EIGRP does not use hop count, cost (used by OSPF), or MTU (Maximum Transmission Unit) for metric calculations by default.