2.0 Communication

Question 2

What does HTTP stand for?

Answer 2

Hypertext Transfer Protocol

HTTP is a method for encoding and transporting data between a client and a server.

Question 3

What type of protocol is HTTP?

Answer 3

Request/response protocol

Question 4

What are the components of a basic HTTP request?

Answer 4

Verb (method) and resource (endpoint)

Question 5

List three common HTTP verbs.

Answer 5

• GET
• POST
• DELETE

Question 6

True or False: The GET method is idempotent.

Answer 6

True

Question 7

Fill in the blank: The _______ method creates or replaces a resource.

Answer 7

PUT

Question 8

What does TCP stand for?

Answer 8

Transmission Control Protocol

TCP is a connection-oriented protocol over an IP network.

Question 9

What is a key feature of TCP?

Answer 9

Connection established and terminated using a handshake

Question 10

What ensures packets are delivered in the original order in TCP?

Answer 10

Sequence numbers and acknowledgment packets

Question 11

What is one disadvantage of TCP compared to UDP?

Answer 11

More delays and less efficient transmission

Question 12

When should you use TCP over UDP?

Answer 12

• You need all of the data to arrive intact
• You want to automatically make a best estimate use of the network throughput

Question 13

What does UDP stand for?

Answer 13

User Datagram Protocol

UDP is a connectionless protocol.

Question 14

What is a key characteristic of UDP?

Answer 14

Datagrams might reach their destination out of order or not at all

Question 15

List two scenarios where UDP is preferred over TCP.

Answer 15

• You need the lowest latency
• Late data is worse than loss of data

Question 16

What is RPC?

Answer 16

Remote Procedure Call

In an RPC, a client causes a procedure to execute on a different address space.

Question 17

What is the main disadvantage of using RPC?

Answer 17

Clients become tightly coupled to the service implementation

Question 18

What does REST stand for?

Answer 18

Representational State Transfer

Question 19

What is a key principle of REST?

Answer 19

Stateless communication

Question 20

List the four qualities of a RESTful interface.

Answer 20

• Identify resources (URI)
• Change with representations (Verbs)
• Self-descriptive error message (status response)
• HATEOAS (HTML interface for HTTP)

Question 21

True or False: REST is focused on exposing behaviors.

Answer 21

False

Question 22

What is a disadvantage of REST?

Answer 22

It can require multiple round trips to fetch complicated resources

Question 23

How is an RPC call structured?

Answer 23

Client calls the client stub, marshals the procedure id and arguments into a request message

Question 24

What is the purpose of HATEOAS in REST?

Answer 24

Ensures the web service is fully accessible in a browser

Question 25

Fill in the blank: REST minimizes the coupling between ______ and ______.

Answer 25

client, server

Question 26

What is one reason to choose a native library for RPC?

Answer 26

You want to control how your ‘logic’ is accessed

Question 27

List three popular RPC frameworks.

Answer 27

• Protobuf
• Thrift
• Avro

Question 28

What is a key difference between RPC and REST in terms of operation?

Answer 28

RPC requires a new API for every new operation; REST uses standard HTTP methods