LinuxQuestions.org
Go Job Hunting at the LQ Job Marketplace
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Networking
User Name
Password
Linux - Networking This forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.

Notices

Reply
 
Search this Thread
Old 05-24-2004, 02:08 PM   #1
Z-Ice
LQ Newbie
 
Registered: Aug 2003
Distribution: Mandrake 9.2
Posts: 13

Rep: Reputation: 0
Question Delayed ACK


I was wondering if anyone knows the timeout for delayed ACK in the kernel 2.4.26? I am using a wireless network and I used ethereal to capture my packets. I noticed many steps in the graph and I feel it is the timeout of the delayed ACK. I was wondering if anyone knows what it is set to or if there is a set number of packets? The delayed ack works fine throughout a transfer I get 2 packets in and one ack back out. After an amount of time(~4.7sec) I get steps. After a while it catches back up and goes on normally. It repeats many times throughout the transfer.

Thanx,
Z-Ice
 
Old 05-24-2004, 03:00 PM   #2
Mara
Moderator
 
Registered: Feb 2002
Location: Grenoble
Distribution: Debian
Posts: 9,536

Rep: Reputation: 148Reputation: 148
Are you sure it's bacause of ACKs? Probably it's because of losses? They're quite high when using radio.
 
Old 05-24-2004, 03:12 PM   #3
Z-Ice
LQ Newbie
 
Registered: Aug 2003
Distribution: Mandrake 9.2
Posts: 13

Original Poster
Rep: Reputation: 0
No losses

I looked through the tcpdump and it is not radio losses. Or lost acks. I know delayed ack is running. The 'steps' happen in such a non-random order. There was no interference channels running. I know delayed ack has a timeout: Take a look here http://www.icase.edu/coral/LinuxTCP.html I was wondering when 2.4.26 default is? I need to solve/understand the problem.
 
Old 05-24-2004, 03:44 PM   #4
Mara
Moderator
 
Registered: Feb 2002
Location: Grenoble
Distribution: Debian
Posts: 9,536

Rep: Reputation: 148Reputation: 148
Probably that's it:
Code:
#define TCP_DELACK_MAX  ((unsigned)(HZ/5))      /* maximal time to delay before sending an ACK */
(in include/net/tcp.h)
HZ = 1 sec.
 
Old 05-24-2004, 03:46 PM   #5
Mara
Moderator
 
Registered: Feb 2002
Location: Grenoble
Distribution: Debian
Posts: 9,536

Rep: Reputation: 148Reputation: 148
Moved to Linux - Networking as it's a technical Linux question
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
ACK! what is my problem? zmaster Linux - Software 2 06-21-2005 05:33 PM
Delayed ACK Z-Ice Mandriva 0 05-23-2004 09:39 PM
Forwarding ACK Packets snufferz Linux - Newbie 0 05-12-2004 02:10 AM
ack, im a noob no_order Slackware 2 07-06-2003 09:54 PM
Ack, Help! meddleRPI Linux - General 2 05-23-2003 10:32 PM


All times are GMT -5. The time now is 01:14 PM.

Main Menu
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
identi.ca: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration