Solved

TCP,UDP checksums

Posted on 1997-10-26
1
1,158 Views
Last Modified: 2013-12-23
Hello,
Why do TCP and UDP have their own checksums?Is the IP checksum not enough?
and Why lost TCP acknowledgements do not necessarily force retransmissions?
Thanks.
0
Comment
Question by:bpmf
1 Comment
 
LVL 1

Accepted Solution

by:
Joshua111197 earned 100 total points
Comment Utility
Hey,

TCP and UDP are protocols at the similar OSI-Layer, but UDP is no secure end-to-end-protocol, because no acknoledgements are sent from the destination and a checksum has not to be calculated  (checksum=0 means, no checksum will be calculated). So transmission errors can only be checked by IP checksum.

The TCP-checksum is calculated to secure the transmission of the data from Layer 4 to Layer 3 (IP). The original data will be checked here. The IP checksum will vary on every hop, because the IP header has the source adress and the destination adress of the next hop inside. So with every router on the run the checksum will be a different. The TCP-checksum can controll changings of the original data.

The retransmissions are not builded bye the TCP protocol but bye the application. The RFCs for TCP only describe the TCP-packet but not the applications they are created by. So I think, the ability  to force retransmission depends on the application.

I hope this will answer your questions.

Yours Josh
0

Featured Post

Find Ransomware Secrets With All-Source Analysis

Ransomware has become a major concern for organizations; its prevalence has grown due to past successes achieved by threat actors. While each ransomware variant is different, we’ve seen some common tactics and trends used among the authors of the malware.

Join & Write a Comment

Suggested Solutions

The DSL Parameters part of this article is valid and can be considered with any brand of internet router and modem (Dlink, 3com, Alcatel, Usrobotics, Parks), by accessing the configuration interface available by the manufacturer eg: http://10.1.1.1 …
Some time ago I was asked to set up a web portal PC to put at our entrance. When customers arrive, they could see a webpage 'promoting' our company. So I tried to set up a windows 7 PC as a kiosk PC.......... I will spare you all the annoyances I…
This video gives you a great overview about bandwidth monitoring with SNMP and WMI with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're looking for how to monitor bandwidth using netflow or packet s…
In this tutorial you'll learn about bandwidth monitoring with flows and packet sniffing with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're interested in additional methods for monitoring bandwidt…

743 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

12 Experts available now in Live!

Get 1:1 Help Now