The Gateway to Computer Science Excellence
First time here? Checkout the FAQ!
x
+23 votes
2.2k views

Which of the following statements are TRUE?

  • S1:  TCP handles both congestion and flow control
  • S2:  UDP handles congestion but not flow control
  • S3:  Fast retransmit deals with congestion but not flow control
  • S4:  Slow start mechanism deals with both congestion and flow control
  1. $S1$, $S2$ and $S3$ only
  2. $S1$ and $S3$only
  3. $S3$and $S4$ only
  4. $S1$, $S3$ and $S4$ only
asked in Computer Networks by Boss (19.1k points)
edited by | 2.2k views
–2
s2 and s4 are only correct
0
s3 is also correct because in slow start we consider both the receiver window size and congestion window size. so it takes care of both flow control and congestion control
0
see the gate ques...explaination in ans
–2
you are correct . ss deals with congestion control only
+1
Imp point -> Slow start is way Sender tries to gauge network capacity.
0

Slow start does take into account the receiver's advertised window. And is this is not precisely "flow control"? Shouldn't this make option d the right choice?

Reference- Wikipedia.

Caption

 

2 Answers

+42 votes
Best answer

(S1)  TCP handles both congestion and flow control $\Rightarrow$ True.
 IT uses congestion window for congestion control & Advertisement window for flow control
(S2)  UDP handles congestion but not flow control $\Rightarrow$ UDP does not handle
congestion but also not handle flow control.
(S3)  Fast retransmit deals with congestion but not flow control$\Rightarrow$ Yes.
Fast Retransmit is technique for detecting out of Order Datagram & Sending it.
It is congestion control technique and has no relation with Flow control
(S4)  Slow start mechanism deals with both congestion and flow control $\Rightarrow$ False.
It has nothing to do with Flow control. Flow control is taken care by Advertisement window.
Slow start is way Sender tries to gauge network capacity !
Answer (B) S1 and S3 only.

answered by Boss (43k points)
edited by
+2

Excellent explanation.yes

+2
Flow control also uses fast tramsmission rule.

Even if we are not apllying congestion policies say rcvd<cwd,in this case also if some frame's ack is lost then also tcp transmits after 3 dup acks,please check and tell.
0
can somebody expalain s3 statment in detail
0

@ Moin Mukhtar

In fast retransmit whenever the sender gets 3 ack of same sequence number it can safely assume that that packet has been lost and it retransmits the packet without waiting for the time out.

+13 votes

Tcp handles both Congestion Control and Flow Control. For Flow Control it uses Sliding Window Protocol Algorithms and for Congestion Control it uses four congestion control algorithms: slow start, congestion avoidance, fast re-transmit, and fast recovery.

So Option (B)

answered by Active (3.9k points)
0
Yes, and UDP has no congestion avoidance whatsoever!

So, option B.
0
I think option should be D. Because Slow start also considers receiver window size.
0
B should be the answer
0
Can you explain what is fast recovery?

@Danish
Answer:

Related questions



Quick search syntax
tags tag:apple
author user:martin
title title:apple
content content:apple
exclude -tag:apple
force match +apple
views views:100
score score:10
answers answers:2
is accepted isaccepted:true
is closed isclosed:true

42,296 questions
48,419 answers
153,539 comments
62,661 users