What are the three layers of the Cisco Hierarchical Model?
The three layers of the Cisco Hierarchical Model are:
  1. the access layer
  2. The distribution layer
  3. The core layer
In the Cisco Hierarchical Model, what is the function of the access layer?
Sometimes referred to as the desktop layer, the access layer is the point at which users connect to the network through low-end switches. Some functions of the access layer include:
  1. Connectivity into the distribution layer
  2. Shared Bandwidth
  3. MAC Address filtering (switching)
  4. Segmentation
What is the function of the distribution layer in the Cisco Hierarchical Model?
The distribution layer is also known as the workgroup layer. It is the demarcation point between the access and core layers of the network. Its primary function is to provide routing, filtering, and WAN access. The distribution layer determines how packets access the core, so it is the layer at which to implement policy-based connectivity.

Some functions include the following:
  1. Collection point for access layer devices
  2. Broadcast and multicast domain segmentation
  3. Security and filtering services such as firewalls and access lists
  4. Providing translation between different media types
  5. Inter-VLAN routing
What is the role of the core layer in the Cisco Hierarchical Model?
The core layer is the backbone of the network. Its main function is to switch traffic as fast as possible. Therefore, it should not perform any filtering to slow down traffic. The ISO's OSI Reference Model contains seven layers. What are they? Include the layer number and name of each layer in your answer.

The seven layers of the OSI model are as follows:
  1. Layer 7 - Application layer
  2. Layer 6 - Presentation layer
  3. Layer 5 - Session layer
  4. Layer 4 - Transport layer
  5. Layer 3 - Network layer
  6. Layer 2 - Data link layer
  7. Layer 1 - Physical layer
What are some reasons that the industry uses a layered model?
Here are some reasons why the industry uses a layered model:
  1. It encourages industry standardization by defining what functions occur at each level.
  2. It allows vendors to modify or improve components at only one layer versus rewriting the whole protocol stack.
  3. It helps interoperability by defining standards for the operations at each level.
  4. It helps with troubleshooting.