What are two descriptions of three-tier network topologies? (CCNA 200-301)

Correct answer: A) The distribution layer runs Layer 2 and Layer 3 technologies and B) The network core is designed to maintain continuous connectivity when devices fail..
Three-tier network topologies are a type of network architecture that divides the network into three layers: the core layer, the distribution layer, and the access layer. Each layer has specific functions and characteristics. Based on the descriptions provided, the two correct descriptions of three-tier network topologies are:

A) The distribution layer runs Layer 2 and Layer 3 technologies.

This description is accurate because the distribution layer in a three-tier network topology is responsible for routing traffic between the core layer and the access layer. It operates at both Layer 2 (Data Link Layer) and Layer 3 (Network Layer) of the OSI model. This layer uses technologies like Ethernet for Layer 2 and IP for Layer 3 to facilitate communication across different parts of the network.

B) The network core is designed to maintain continuous connectivity when devices fail.

The core layer is the backbone of the network, responsible for high-speed data transmission between the distribution layer and the access layer. Its primary function is to ensure that data can be transmitted efficiently and reliably across the network. This includes maintaining continuous connectivity, even when some devices fail or are disconnected. The core layer is designed to handle high volumes of traffic and to be resilient to failures, ensuring that the network remains operational.

The other options provided do not accurately describe the characteristics of three-tier network topologies:

C) The access layer manages routing between devices in different domains. This is incorrect because routing between different domains is typically handled by the core and distribution layers, not the access layer.
D) The core layer maintains wired connections for each host. This is not a primary function of the core layer. The core layer is more concerned with high-speed data transmission and connectivity rather than maintaining wired connections.
E) The core and distribution layers perform the same functions. This is incorrect because the core and distribution layers have distinct roles in a three-tier network topology. The core layer is the backbone of the network, handling high-speed data transmission, while the distribution layer is responsible for routing traffic between the core and access layers.