internet protocol stack (2)

Question 1

what is the main function of the transport layer

Answer 1

to provided end to end communication between application process on different host

Question 2

name 2 transport layer protocol

Answer 2

udp ( user datagram protocol)
tcp (transmission control protocol)

Question 3

what do port number specify

Answer 3

specify processes running on a host

Question 4

which protocol is connection oriented

Answer 4

tcp

Question 5

what does a socket consists in a tcp

Answer 5

a 4 tuple - source ip, source port, destination ip, destination port

Question 6

how does the receiver know which app a segment belongs to

Answer 6

it checks the destination port number in the transport header

Question 7

give an example of an application that commonly uses udp

Answer 7

DNS, streaming video

Question 8

what field in the tcp header is used for control flow control

Answer 8

the receive window (rwnd)

Question 9

what is the purpose of the tcp checksum

Answer 9

to detect bit level errors in the segment

Question 10

what does the tcp flow control prevent

Answer 10

prevents the sender from overwhelming the receiver buffer

Question 11

why is the udp considered best effort

Answer 11

it doesn’t guarantee delivery, order or error correction

Question 12

why do some application still use udp despite its unreliabilty

Answer 12

it is faster and suitable for apps that tolerate some loss (like video or audio streaming)

Question 13

whats the difference between flow control and congestion control

Answer 13

flow control
It is between the sender and the receiver
Prevents buffer overflow

congestion control
between the sender and the network
prevents network overload