Introduction to IP

Question 1

What is IP? What is it responsible for?

Answer 1

IP is Internet Protocol. It is responsible for taking data from one end of the network and moving it to the other end.

Question 2

Using the truck analogy, what is the following:
Truck
Road
Boxes (Inside the Truck)
Inside Boxes

Answer 2

Truck is the IP
Road is the network topology (Ethernet/DSL/Cable System)
Boxes are data (TCP/UDP)
Inside Boxes is application information

Question 3

Describe the interaction between Client and Server via Ethernet

Answer 3

Client > Ethernet Header > IP > TCP/UDP > DATA (HTTP/VoIP/Email) > Ethernet Trailer > Server

Question 4

What layer of OSI does TCP/UDP fall under?

Answer 4

OSI Layer 4, the transport layer

Question 5

What is multiplexing? What is this a feature of?

Answer 5

Allows us to use multiple different applications at the same time. This is a feature of TCP/UDP.

Question 6

What is TCP? Elaborate.

Answer 6

Transmission Control Protocol. It is connection-oriented. Data is transferred, then terminated. It has a “reliable” delivery method. We can expect a “receipt” of delivery. The receiving device can control the flow of traffic, and can manage out-of-order messages or re-transmissions.

Question 7

What is UDP? Elaborate.

Answer 7

User Datagram Protocol. It is a connection-less protocol. It sends data when it is available, and hopes the receiver is ready to receive. It has “unreliable” delivery, so there is no reordering of data, no error recovery, and no verification of received data. No flow control.

Question 8

Referring to the Truck Analogy, the IP delivery truck delivers from one IP address to another IP address. Where do the boxes (truck cargo) go?

Answer 8

The boxes (data) would go to the “rooms” of the house, which would be the port.

Question 9

Summarize the list of components used to get data from one side to another using IP.

Answer 9

Server IP Address -> TCP/UDP Protocol -> Server Application -> Port Number.
Client IP Address -> TCP/UDP Protocol -> Client Port Number

Question 10

What is a non-ephemeral port? Which range of ports are non-ephemeral?

Answer 10

Non-ephemeral means non-temporary (Permanent). So non-ephemeral ports are permanent ports.
These are Ports 0 - 1023.
Usually on a server or service.
Commonly would be server IP Address.

Question 11

What is an ephemeral port? Which range of ports are ephemeral?

Answer 11

Ephemeral means temporary. So ephemeral ports are temporary ports.
These are Ports 1024 - 65,535.
Client decides to use randomly, as it’s sending information back to the server.
Commonly would be client IP Address.

Question 12

What is the range of TCP and UDP port numbers?

Answer 12

0 and 65,535.

Question 13

What are port numbers for?

Answer 13

Communication.

Question 14

What is a common server example that would use UDP?

Answer 14

VoIP Server. Sends data (Voice chat), and hopes the receiver is ready to receive.

Question 15

What is a common server example that would use TCP?

Answer 15

Email Server. Sends data (Email), and there is confirmation (Receipt).

Question 16

What is ICMP? Describe it and give an example. What is it commonly used for?

Answer 16

Internet Control Message Protocol. An example is “Text messaging” for network devices. Commonly used for administrative use. Example: a device requesting/replying to administrative requests, i.e. Device -> ICMP Message (Is this device here? -> Response (Yes, this device is here.)