LinuxQuestions.org
Share your knowledge at the LQ Wiki.
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 01-27-2009, 03:44 AM   #1
ivanatora
Member
 
Registered: Sep 2003
Location: Bulgaria
Distribution: Ubuntu 9.10, FreeBSD 7.2
Posts: 459

Rep: Reputation: 31
Very low network performance in host-to-host connections


Hello,
The situation is that:

(Internet)-->TP Link wireless device (WR543G)-->PC Router-->(internal network)

The internal network is behind nat done by the PC Router.
The TP Link is recieving wireless signal from outdoors and it has switching and basic routing capabilities. I'm using the PC router for better routing options.
PC Router (or R for short) is a triple-booting machine - Linux, FreeBSD and Windows. It has two lan cards - external (ext_if) - 100Mbps Realtek 8139 and internal (int_if) - 1Gbps integrated Realtek 8169.
The problem is that all traffic from R to the network is slow - about 5-20K, while the traffic in the oppoiste direction is all right - about 10MB that is fine for 100Mbps cables, NICs and switches. The problem persist no matter the OS the pc R is running.
I've tried some debugging on the situation as follows:
- put another PC at the place of R - everything is fine. That exclude the possibility of damaged cables, RJ-45s, switches and etc.
- connected both of the NICs to the Internet while the internal network is being disconnected and they both work fine (no delays)
- traffic shaping is not running
- there is nothing in firewalls except NATing the internal network (and it is working fine). Actually these firewall rules have been operational for more than months and everything was fine untill a week or two ago.
- changed the internal NIC with another
- connected the internal network directly to the TP and all of the PCs are getting good network performance. Then connected the R machine to the TP as well and there was good performance between the internal network PCs and R.
- R has good performance to the TP. In fact everything has good performance directly to the TP (when not connecting trough R).
- the problem persist only between R and machines from the internal network.

Any ideas what might be going on?
 
Old 01-27-2009, 12:29 PM   #2
rossonieri#1
Member
 
Registered: Jun 2007
Posts: 359

Rep: Reputation: 34
hi,

if you are using linux as your pc router - try to check your internal NIC duplex setting using mii-tool? and in which speed it operates. does your hub/switch support that 1gbps speed? supporting jumbo frame? but usually - crossover cable from NIC to hub is the problem.

HTH.
 
Old 01-28-2009, 03:00 PM   #3
ivanatora
Member
 
Registered: Sep 2003
Location: Bulgaria
Distribution: Ubuntu 9.10, FreeBSD 7.2
Posts: 459

Original Poster
Rep: Reputation: 31
It was faulty cable. Too long (about 90 meters), broken at several places and wet (it was outdoors placed). I guess parameters of the cable have been graduately worsen with time and now the linux driver won't anymore even try to use the link We've changed the cable topology, shorten 20 meters of it and now it is driving 100 Mbps with ease.
 
  


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
Routing between host and vmware host-only network astbis Linux - Networking 2 12-27-2007 08:21 PM
Low Overhead OS to host a VMWARE instance digitalmastermind Linux - Desktop 4 10-29-2007 04:18 PM
Required to achieve host to host communication via USB file transfer cable may1284 Linux - General 1 03-14-2007 04:02 PM
multiple connections from the same host port 80 paranoid times Linux - Security 1 02-10-2007 01:51 AM
Resolving <www.some remote host>.... failed: Host not found. koodoo Linux - Newbie 2 06-27-2005 08:48 AM

LinuxQuestions.org > Forums > Linux Forums > Linux - Networking

All times are GMT -5. The time now is 05:27 PM.

Main Menu
Advertisement
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
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration