Which two functions are performed at the core layer of the three-layer hierarchical network design model? (Choose 2)

QoS classification and marking is a distribution layer function because it is the policy boundary between the access layer and the core; the core trusts and forwards already-marked traffic.

The core layer's primary role is fast transport - it switches packets as quickly as possible between distribution blocks using high-speed hardware with minimal processing overhead.

Reliability at the core is achieved through redundant hardware, links, and routing protocols so that no single failure disrupts connectivity across the entire network.

Fault isolation is a distribution layer responsibility, where summarization and policy boundaries prevent failures in one part of the network from propagating to the core.

Load balancing across paths is handled at the distribution layer using routing policies, not at the core, which simply forwards at maximum speed.