SHARE
SPREAD
HELP

The Tradition of Sharing

Help your friends and juniors by posting answers to the questions that you know. Also post questions that are not available.

To start with, Sr2Jr’s first step is to reduce the expenses related to education. To achieve this goal Sr2Jr organized the textbook’s question and answers. Sr2Jr is community based and need your support to fill the question and answers. The question and answers posted will be available free of cost to all.

The pleasure of all reading is doubled when one lives with another who shares the same. -Katherine Mansfield

 

#
Authors:
James F. Kurose, Keith W. Ross
Chapter:
Transport Layer
Exercise:
Problems
Question:5 | ISBN:9780132856201 | Edition: 6

Question

Suppose that the UDP receiver computes the Internet checksum for the received UDP segment and finds that it matches the value carried in the checksum field. Can the receiver be absolutely certain that no bit errors have occurred? Explain.

TextbookTextbookTextbookTextbookTextbookTextbookTextbookTextbookTextbookTextbookTextbookTextbookTextbookTextbookTextbookTextbookTextbook

Answer

Certainty of no bit errors at receiver end using checksum using UDP:

 

The receiver in the UDP (User Datagram Protocol) verifies the received segment by calculating internet checksum and comparing it with the value in the checksum field.

  • The 1’s compliment of the sum is considered as checksum. So, when this check sum is used to detect the errors in the packet, the errors remain in under cover.
  • In case, if two 16-bit words are added, then there is a scope for flipping the 0’s and 1’s. If the bits are flipped, the sum will be same and error can’t detected.

 

Therefore, it is not possible to the receiver in UDP to be sure that there are no bit errors have occurred.

0 0

Discussions

Post the discussion to improve the above solution.