Network Programming

Question 1

TCP

Answer 1

Transmission Control Protocol

Prevents errors with package loss, out of order, duplicated, etc.

Question 2

UDP

Answer 2

User Datagram Protocol

Provides no protection against package errors

Question 3

Socket

Answer 3

An application can use a socket to communicate with another process - can be used like a file to read/write to

Question 4

AF_UNIX domain

Answer 4

Used for local communication

Question 5

AF_INET, AF_INET6

Answer 5

INET for IPv4 internet protocols, INET6 for IPv6 internet protocols

Question 6

IPv4 vs IPv6

Answer 6

IPv4 uses 32 bit IP address, IPv6 uses 128 bit IP addresses

Question 7

TCP Server Socket Sequence

Answer 7

1. socket
2. bind
3. listen
4. accept.
5. read
6. write
7. close

Question 8

UDP Client Socket Sequence

Answer 8

1. socket
2. connect
3. write
4. read

Question 9

bind()

Answer 9

binds a socket to an address, used by server

Question 10

listen()

Answer 10

marks the socket as passive, used to wait for a connection to come

Question 11

accept()

Answer 11

returns a new connection, i.e. a new socket to use for connection

Question 12

connect()

Answer 12

connect to passive socket, used by client

Question 13

Connection-oriented

Answer 13

make a connection first before transmitting any data

Question 14

UDP server socket sequence

Answer 14

1. socket
2. bind
3. recvfrom
4. sendto
5. close

Question 15

sendto, recvfrom vs. read, write

Answer 15

read, write are universal file descriptor functions, the others are socket-specific

Question 16

AF_INET vs AF_INET6

Answer 16

AF_INET uses 4 bytes for addresses, AF_INET6 uses 16 bytes for addresses

Question 17

Loopback address

Answer 17

127.0.0.1 - INADDR_LOOPBACK

refers to local address

Question 18

Wildcard address

Answer 18

INADDR_ANY

binding a socket to the wildcard address tells the OS we want to listen on any address

Question 19

Ephemeral port

Answer 19

If you don’t call bind, then a port number will be chosen for you

Question 20

Little endian vs. big endian

Answer 20

Little endian: little end/least sig. byte goes first
Big endian: big end/most sig. byte goes first