Module 1 - Intro to Networking & Services

Question 1

What are the advantages of protocol layering?

Answer 1

Protocol layering provides a way to simplify a complex problem by dividing it into a number of smaller functions. Each layer performs a specific function.

Question 2

What are the four layers of technology used in the TCP/IP protocol suite?

Answer 2

Application Layer, Transport Layer, Internet Layer, and Link Layer

Question 3

What is Data Encapsulation?

Answer 3

Data encapsulation is the mechanism by which each layer in the protocol stack adds information to the application-generated data. That information is intended to be interpreted by an entity of the same layer in a remote device, in such a way that the data is properly processed and delivered to the intended receiver and to the right application.

Question 4

Describe the Application layer of the TCP/IP Suite

Answer 4

The Application layer packages the data in such a way that it can be properly interpreted at the remote end.

Question 5

Describe the Transport Layer of the TCP/IP Suite

Answer 5

The Transport Layer breaks the information into smaller segments that can be transported from end to end and passes them down to the Internet layer.

Comprised of two main protocols: TCP and UDP

Question 6

Describe the Internet Layer of the TCP/IP Suite

Answer 6

The Internet Layer provides end-to-end addressing and carries the data packets from source to destination.

Universal and consistent forwarding service across a TCP/IP network

Question 7

Describe the Link Layer of the TCP/IP Suite

Answer 7

The Link Layer has to do with local hop-by-bop addressing, data framing, and medium access control; it assumes there is a mechanism in place to transmit signals from one device to the next.

Defines the actual interfaces between nodes

Ethernet

Question 8

Define a Layer-2 Broadcast Domain

Answer 8

• All hosts are connected to the same Local Area Network (LAN)
• There may be several LAN segments interconnected by switches which make forwarding decisions based on MAC addresses
• All hosts obtain IP Addresses with the same prefix, also known as an IP Subnet, which identifies the layer-2 domain.

Question 9

Define a Layer-3 Domain

Answer 9

• There may be two or more layer-2 broadcast domains (subnets) interconnected by routers, which make forwarding decisions based upon IP Addresses
• When an IP packet needs to be sent to a host in a different subnet it is first sent to a router.

Question 10

What are functions of the control plane?

Answer 10

• Enable routers to exchange control messages and to agree on the best way to forward packets
• Establish the necessary routing paths and/or tunnels required to deliver packets from source to destination

Question 11

What are functions of the Data Plane?

Answer 11

• Use forwarding tables created by control-plane functions to properly forward every data packet towards its intended destination.

Question 12

What occurs when a packet travels from an upper layer to a lower layer?

Answer 12

The data is encapsulated with a new header

Question 13

What occurs when a packet travels from a lower layer to the upper layer?

Answer 13

A layer-specific header is removed from the data

Question 14

What happens to the link-layer header at each router?

Answer 14

A new layer-2 header/link-layer header is created