Networking :: Simulate A 500Mbps Link On A 1000Mbps?
Mar 31, 2010
I need to simulate a 500Mbps link with a 100ms delay and a loss probability of 0.0001% on an ethernet link between two gigabit ethernet cards...I tryed to use these commands:
# tc qdisc add dev lo root handle 1:0 netem delay 100ms loss 0.0001
# tc qdisc add dev lo parent 1:1 handle 10: tbf rate 500Mbit buffer XXXX limit YYYYY
But during some simulation throughputs are very low ( 190Kbps....210Kbps....) for different values of XXXX and YYYY.... (I don't want that the loss probability is caused by the buffer and the limit value but only by the loss probability setted on netem...)
I've two computers with 1000Mbps cards, one opensuse 11.2 32 bits (AMD K7 over 1Ghz and 2MB RAM) and the other Opensuse 11.3 11.3 64 bits (single processor, 3GB). Both of the cards are configured with skge. The swith is an SMC 10/100/1000 and it reports connection at 1000Mbps on both cards. The i386 is a server and the other is a client.
I've in the client some directories of the server mounted by nfs. I'm testing the connection copying long files (1GB for instance) and the copy reaches 14MBps at most, and most of the time it is more or less at 10MBps, which is too far from 1000Mbps.
It may be a problem of configuration? The switch is not good enough? or may be another kind of problem ?
I've been doing some reading and I cannot work out why I'm having this problem. My 32-bit Ubuntu Server running 10.10 has a Realtek RTL8111 ethernet card which supports up to 1000mbps. However, when I run sudo ethtool eth0 I get:
Code: Settings for eth0: Supported ports: [ TP MII ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full
[Code]....
After running sudo ethtool -s 1000 to try and change speed to 1000mbps, the output is still the same as before. Why is this :S?
I'm trying to configure the following network card to work with a 1000Mbps switch:
Code: 04:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8101E/RTL8102E PCI Express Fast Ethernet controller (rev 01) I think the problem is the network card module. When I run ethtool eth0 nothing of 100Mbps is showed:
I have a problem where I'm using Ubuntu linux to mount a Windows Vista machine's USB drive and access it on the web using Apache. I did have the USB drive plugged into the Linux machine directly and that was working via the web. FollowSymLinks is on in httpd.conf
[Code]....
The mount works and I can see the files (see above) from my regular linux user account. If I make a test file in /mnt and soft link to that, I can see it on the web. So it's just the mount to the vista machine that seems to be a problem. It's supposed to be a simple read-only mount and the apache login should (I think) be able to see the same generic root access permissions.
log from apache: [Mon Apr 26 20:39:42 2010] [error] [client 99.99.99.99] Symbolic link not allowed or link target not accessible: /home/user1/pub_html/Music, referer: https://xx.xx.xx/~user1/music.html
The credentials have a login and password that matches a special read-only account on Vista. I can see the files on the system from Linux, but not via the web. As mentioned above, a different link to the same /mnt area works fine via the web. I've tried several different mount options with no success.
I'm trying to simulate a script for two UES connected with a high speed common channel. The file is the same I've used in not enhanced umts with some changes, and it worked perfectly. The changes are indicated in the EURANE guide.
There are two lines of code:
Code: $bs setErrorTrace 0 "UE1_trace_file" $bs setErrorTrace 1 "UE2_trace_file" that give me an error when I try to run the file .tcl I've downloaded files I needed from EURANE page: SNRBLERMatrix and Ray_corr-3kmh-300m-0-200s-UEnr1,Ray_corr-3kmh-500m-0-200s-UEnr1,Ray_corr-3kmh-700m-0-200s-UEnr1 I've tried to use the first and the third for UE1 and UE2 respectively
[Code]...
I edit: The definition of the connection of TCP agents and sinks was incorrect.
i only need localhost for testing some phpnow i get[Wed Apr 28 18:44:57 2010] [error] [client ::1] Symbolic link not allowed or link target not accessible: /srv/www/htdocs
In the ordering of files I keep I need links to directories. Sometimes I even need to move directories to new locations. I have tried using symlinks, but they become dead when I move the directory they point to. I have tried hard links, but I haven't found any Linux file system that would support hard linked directories. How can I achieve that a complex structure of directories (currently with symlinks for directories and hard links for files) keep symlinks live when directories are moved?
- is there any utility that updates symlinks when a directory is moved?
- is there any Linux filesystem that supports hard linked directories?
- is there any good Linux interface to the new NTFS (the only file system I know to support automatically updating directory links, called directory junctions)?
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could not do simulate: Traceback (most recent call last): File "/usr/share/PackageKit/helpers/yum/yumBackend.py", line 3270, in __init__ self.repos.confirm_func = self._repo_gpg_confirm File "/usr/lib/python2.6/site-packages/yum/__init__.py", line 823, in <lambda> repos = property(fget=lambda self: self._getRepos(), File "/usr/lib/python2.6/site-packages/yum/__init__.py", line 551, in _getRepos prerepoconf = self.prerepoconf AttributeError: 'PackageKitYumBase' object has no attribute 'prerepoconf'
I wrote software which access and reads a serial device. I would like to test this software on my computer without loop-wiring or without a second computer.
How could I use pty's to simulate a serial device?
Actually I would like to temporary replace the /dev/ttyS1 file by one end of the pty. How could I do this? Is there a command to create a pty pair?
When I drink tea, the water splashed on my keyboard. It didn't cause any problems until a few mins ago. Now my Enter and right hand side shift key don't function any more (The new line in this text is copied from other thread).
So I would like to know how can I simulate an enter key press so that e.g. a command can be executed in terminal. Because I have some source code uncommitted, I want them at least get committed first.
I'm trying to save the output of the script I wanna run but for some reason I cant manage to do it with "script.sh > Output_4.txt"
The thing is that the script was already run and it extracted some directories so when I try to run it again (to save the log to a Output_4.txt) bash says (see screen-capture) and of course the log's empty!!!!
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I have ack-grep installed on my local machine, and find it indispensable for quickly 'acking' through a codebase when debugging. However, on my cheap shared hosting, there is no ack-grep. One of the testimonials on betterthangrep.com mentions a
Rube Goldberg mess of find/grep/xargs which sounds like what I need, but coming from the opposite direction.
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The program I am running is partly java and partly shell.
The shell part is easily done by using: ./prog.sh <parameters (Parameters being a file containing parameters) But the java doesn't work similarly.
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I've just installed ubuntu 11.04 on my dell inspiron mini 10; dual-booting it with Windows 7.
I've looked at a couple of other threads about problems with the wireless card in the netbook and about problems with the wireless router. However, this problem doesn't seem to be the same; the netbook can see other wireless networks, just not mine, and other people seemed to be able to access their wireless network for a short period of time before they stopped being able to access it.
I can't see the wireless network on the D-link DIR-615 at all in ubuntu, though it still works in windows 7.
I've tried reinstalling the broadcom STA drivers as per this link and reinstalling but this hasn't made any difference.
What things should I consider trying in order to resolve this?
Ps. As a side note, my other ubuntu laptop (a toshiba equium A100) cannot see this network either, but has no problem connecting to other, although oddly it couldn't detect it in windows either before I put in a new harddrive and installed ubuntu on it.
