Chapter 1 - Introduction to Switched Networks

Question 1

What are one of the main reasons to use a converged network?

Answer 1

To combine several features into one physical network. Including: Call control: Voice messaging, Mobility, Automated attendant.

Question 2

What are the three layers in the hierarchy of a converged network?

Answer 2

Core Layer, Distribution Layer, Access Layer.

Question 3

What is the purpose of the Hierarchical principle?

Answer 3

Understanding the role of each device in every tier. This simplifies deployment, operation and management. This reduces fault domains at every tier.

Question 4

What is the purpose of the Modularity principle?

Answer 4

To enable seamless network expansion and integrated service enablement on an on-demand basis.

Question 5

What is the purpose of the Resiliency principle?

Answer 5

To satisfy user expectations and keeping the network always on.

Question 6

What is the purpose of the Flexibility principle?

Answer 6

To allow intelligent traffic load, by sharing all network resources.

Question 7

What is the purpose of the Access Layer?

Answer 7

To provide network access to the user.

Question 8

What is the purpose of the Distribution Layer?

Answer 8

To provide intelligent routing and switching functions to access the rest of the network, aggregate Layer 2 broadcast domains and Layer 3 routing boundaries. Also provides high availability through redundant switching.

Question 9

What is the purpose of the Core Layer?

Answer 9

To provide a robust backbone with fault toleration and high speed connectivity.

Question 10

What are the roles of a switched network?

Answer 10

To provide quality of service, additional security, wireless connectivity and IP telephony.

Question 11

What are the three main form factors to consider, when choosing a switch configuration?

Answer 11

Fixed Configuration, Modular Configuration and Stackable Configuration.

Question 12

What two criteria does a switch consider when forwarding a frame?

Answer 12

Ingress port and destination address.

Question 13

What is the purpose of the MAC address (or CAM) table?

Answer 13

To map MAC addresses to ports.

It associates the source MAC address to the port, from which it receives traffic.

Question 14

What are the characteristics of store-and-forward switching?

Answer 14

To provide a reliable method of transport, in which the frame is checked for errors. This is known as the frame-check-sequence (FCS) or CRC. Higher latency than cut-through switching.

Question 15

What are the characteristics of cut-through switching?

Answer 15

To provide a fast method of forwarding frames. This method does not check the frame for errors. Provides lower latency than store-and-forward.

Question 16

What is a collision domain?

Answer 16

A medium where devices must take turns to send or receive content. Ideally there should only be one device per collision domain.

Question 17

What happens if a frame is broadcasted?

Answer 17

It enters the broadcast domain, which forwards it to all devices connected to the network. A router or a layer 3 switch is needed to split the broadcast domain.