Introducing the Application Layer

Question 1

____ allow application programs to allow information to travel though the network core

Answer 1

APIs

Question 2

If an application is built on a ___ network, the application itself must ensure that the communications are ______

Answer 2

UDP, reliable

Question 3

______ provide services to other hosts

Answer 3

servers

Question 4

A service may be provided by a group of servers if it is the service is ________ used

Answer 4

heavily

Question 5

With a ___ network application architecture, hosts __________ directly with each other (no _______)

Answer 5

P2P, communicate, server

Question 6

A P2P architecture is __________, highly distributed, and can be __________

Answer 6

decentralized, unreliable

Question 7

Applications can be a hybrid of ______-______ and ___ architectures (like instant messaging)

Answer 7

client-server, P2P

Question 8

An issue with P2P is that it increases _______ traffic and _______ ISPs with asymmetric services

Answer 8

upstream, stresses

Question 9

An issue with P2P architecture is that it’s difficult to prove ________

Answer 9

security

Question 10

An issue with P2P architecture is that supporting P2P is supporting _______ applications

Answer 10

illegal

Question 11

To build an application that communicates between processes, you need a way to send __________ from one process to another

Answer 11

information

Question 12

An interface for sending messages will likely be the interface to the _______ layer

Answer 12

transport

Question 13

A socket API is used to…

Answer 13

build a communication channel in an application

Question 14

A ______ is one end of a communication connection

Answer 14

socket

Question 15

A socket includes 3 things…

Answer 15

1. The address of the host running the process (IP)
2. The address of the process running the host (port)
3. A spec of the transport protocol to use

Question 16

Each socket will…

Answer 16

1. Wait for a request to connect to another socket

2. Mame a request to connect to another socket

Question 17

After 2 sockets are connected, they can begin to transfer __________

Answer 17

information

Question 18

The application level protocol will define the types of _______, the _____ of messages, the _________ of each message, and the rules for __________ each type of message

Answer 18

message, syntax, semantics, processing

Question 19

Different applications require different transport requirements. What are some examples?

Answer 19

1. Applications can tolerate data loss
2. Apps are time sensitive
3. Apps are bandwidth sensitive and require continuous min. throughput
4. Apps can tolerate bursts of throughput