Time out - transport layer, Computer Networking

Assignment Help:

Time  out

Timers  are used to protect  against  lost packet. Each  packet  must have its own logical  timers since  only  a single  packet  will be retransmitted  after timeout. A single  hardware timer can be used to mimic  the function of  multiple logical  timers.

The SR receiver  will  acknowledge  a correctly received packet whether or not it is  in order. Out of order packets  are buffered  until any missing packets ( that  is packets with lower  sequence numbers) are received. The  various actions  taken by the SR receiver.

Packet  with  sequence  number in ( rev base re base + N- 1) is correctly received. In  this case  the received packet falls within the  receiver window  and a selective ACK  packet  is returned  to the  sender.

If  the packet was not  previously  received it  is buffered. If this  packet  has a sequence number  equal to the base of the  window  then this  packet  and any  previously  buffered  and consecutively numbered packets are delivered to the receiver. The  receiver window is them moved  forward  by the number of packets  delivered to the receiver as in figure when a packet  with a  sequence number of 2 is  received  then packets 3, 4 and 5 can  be delivered to the receiver.

Packet with  sequence  number in  ( rev base n rev base-1)  is received. In  this case an ACK  must be  generated this is the packet  which  the receiver has previously  acknowledge.

Otherwise ignores the  packets.

To understand  the functions of SR protocols  lets  take an example  of a window  size of  four packets. The sender  can sends  packets 0 to 3. If  first  packet pkt 0 is  lost  and pkt 1 , 2   and 3 are received by the  receiver instead of discarding these  packets  the receiver  buffers  the packets  and send  the ACK  for the  packets  respectively. After the  time out  of pkt 0 the sender  can retransmit this  lost  packet  pkt 0 if  the receiver receives the lost  packet  pkt 0  then the  receiver deliver all the  packets  which  was kept  buffered  by the  receiver previously.


Related Discussions:- Time out - transport layer

What are the features of star and ring topology, What are the features of s...

What are the features of star and ring topology The three networks have following features: star: best case is = 2, average case is = 2, worst case is = 2 ring: best case

What is an error, Q. What is an Error? At any time bits flow from one p...

Q. What is an Error? At any time bits flow from one point to another they are subject to unpredictable changes because of interference The interference is able to change the

Compute the number of lost packets of the down-stream, A mobile host (MH) i...

A mobile host (MH) is connected to a WLAN access network that uses MIP for mobility support. Consider that the RTTs between MH and HA are 0.3s while RTTs within a L2 subnet are 80

Define client and server, Question 1 Define client and server. Explain the...

Question 1 Define client and server. Explain the Client server model Question 2 What is a Mainframe System? Write down the features of Mainframe System Question 3

Functions of the information security steering committee, Question: (a)...

Question: (a) Do you agree with the following statements (specify your reasons to support your answer for each):- i) Policies are the foundation for the development of sta

Explain about congestion control, Q. Explain about Congestion control? ...

Q. Explain about Congestion control? Congestion control Open-loop congestion control - prevent congestion before it happens retransmission policy - Ret

Error detecting code - parity bit, Error Detecting Code - Parity bit: ...

Error Detecting Code - Parity bit: The general idea for achieving error detection and correction is to add some redundancy (i.e., some extra data) to a message, which receiver

What is the difference between a hub and a switch, What is the difference b...

What is the difference between a hub and a switch? A hub acts as a multiport repeater. Though, as more and more devices connect to it, it would not be able to efficiently manag

Introduction to performance evaluations, INTRODUCTION In this part, th...

INTRODUCTION In this part, the topic of performance evaluation shows those parameters that are devised to calculate the performances of various parallel systems. Achieving the

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd