Beta
×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

Using Linux To Make a Slow, Awful WAN Connection

timothy posted more than 5 years ago | from the too-bad-to-be-true dept.

Networking 110

Julie188 writes "This is a brilliant little Linux trick from Windows fanboy Tyson Kopczynski. He wanted to test a new Windows 7 feature called Branch Cache, which caches remote data on the local machine to reduce traffic on a stressed out WAN connection. But how to fake a crappy WAN? Linux. 'The command that I executed (tc) made use of Linux Traffic Control (a kernel thing) which allows me to easily interject 100ms latency on eth1. Boff, Bonk, Pow, Plop, Kapow, swa-a-p, whamm, zzzzzwap, bam ... instant WAN crappiness,' he writes."

Sorry! There are no comments related to the filter you selected.

Lol. (2, Funny)

Anonymous Coward | more than 5 years ago | (#27527203)

Linux: Because sometimes you want slow and awful.

Re:Lol. (5, Funny)

ushering05401 (1086795) | more than 5 years ago | (#27527227)

Linux, 'cause even Windows techs need real tools sometimes.

Re:Lol. (0, Funny)

Anonymous Coward | more than 5 years ago | (#27527533)

Linux, 'cause even Windows techs can be a real tools sometimes.

There, fixed that for ya!

Re:Lol. (4, Funny)

im_thatoneguy (819432) | more than 5 years ago | (#27527737)

Dear lord if you're going to troll... at least get the grammar right:

Linux, 'cause even Windows techs can be real tools sometimes

Re:Lol. (1)

nog_lorp (896553) | more than 5 years ago | (#27529393)

You realize that was probably the real troll hidden within the more obvious Wintroll.

Re:Lol. (1)

Jurily (900488) | more than 5 years ago | (#27532015)

You realize that was probably the real troll hidden within the more obvious Wintroll.

You realize he's still a moron.

Re:Lol. (1, Informative)

Anonymous Coward | more than 5 years ago | (#27527851)

Let just say its if you follow the networking security setting from MS, you will not have this problem

Re:Lol. (1, Informative)

Anonymous Coward | more than 5 years ago | (#27528747)

Obviously the moderator who gave this an offtopic rating didn't read the fucking article. Its a direct quote.

What a maroon!

Re:Lol. (0, Flamebait)

EthanV2 (1211444) | more than 5 years ago | (#27529223)

It's funny how the post mocking Linux gets modded Flamebait, yet the post mocking Windows gets (Score:5, Funny)

Re:Lol. (1)

hmar (1203398) | more than 5 years ago | (#27529683)

Well, the post mocking Windows was a little clever, the post mocking Linux was just mean.

Re:Lol. (1)

nschubach (922175) | more than 5 years ago | (#27529863)

You could always hang out at http://www.neowin.net/ [neowin.net] if you don't like it. ;)

Re:Lol. (1)

Blakey Rat (99501) | more than 5 years ago | (#27532591)

Windows has tools to do that. We used one when I was testing Xbox 360 Live games for MS that ran on Windows 2000 over ICS, and could inject any amount of latency or packet-loss you wanted.

This is just some guy going with "what he knows" instead of bothering to look for another solution. To suggest it's some kind of deficiency with Windows is stupid.

Re:Lol. (1)

h4rr4r (612664) | more than 5 years ago | (#27533015)

This windows tool is free and the source is available?

ICS is not free last I checked.

Re:Lol. (1)

Blakey Rat (99501) | more than 5 years ago | (#27533345)

I really don't know, I only used it when I worked at Microsoft, and obviously when you work for them the licensing isn't that big a deal. I'm nearly 100% sure it was, at the very least, part of the Xbox 360 development kits, which means it could also be a standard component of Visual Studio. But I really don't know.

Also, who cares if the source is available as long as it works?

Re:Lol. (1)

h4rr4r (612664) | more than 5 years ago | (#27533433)

For when it does not work, so you can fix it.
Or for when MS or whoever stops supporting it.

so.... (5, Funny)

Anonymous Coward | more than 5 years ago | (#27527209)

Linux has to be forced to degrade network performance. Windows does it automatically.

Did MS ever fix that 10 TCP/IP connection limit?

Re:so.... (5, Funny)

Anonymous Coward | more than 5 years ago | (#27527243)

Did MS ever fix that 10 TCP/IP connection limit?

What? So if I open a tenth browser tab I won't be abl

Re:so.... (5, Funny)

BattleApple (956701) | more than 5 years ago | (#27528241)

well at least it hit the submit button for you before crashing

Re:so.... (3, Interesting)

Anonymous Coward | more than 5 years ago | (#27528193)

I think the still haven't fixed the thing where Vista is limited [technet.com] to 100mbps if you are also playing audio [slashdot.org] .

They should have stuck with the BSD network stack. As many bugs as they inserted into it to make it vulnerable, it still would pass traffic at the full data rate.

Re:so.... (2, Interesting)

digitalunity (19107) | more than 5 years ago | (#27530093)

I've found when transferring files across my local network, if I have any audio applications open I can't get more than 28-30 Mbps out of my wireless. If I close the audio application, I can often get over 40 Mbps.

Re:so.... (1, Informative)

Vectronic (1221470) | more than 5 years ago | (#27528249)

No, XP, Vista, Win7 all have the limit, but I'm not so sure about Server versions.

They don't consider it a "flaw", as they boast it as malware limiting, and under most situations, it's irrelevant because 10 new connections a second is about 5 times more than most applications need. Excluding P2P, and a few Games.

Event ID: 4226 [microsoft.com]

However, they haven't made it any harder to bypass, Hex editing, or one of a few automated versions out there for XP, Vista and Win7 [google.com] .

Re:so.... (1)

somersault (912633) | more than 5 years ago | (#27528871)

they boast it as malware limiting

That's like a car's windows not being able to close fully and the manufacturer saying "it's a good thing too, because the air conditioning sucks!"

Re:so.... (1)

kenh (9056) | more than 5 years ago | (#27530815)

First off, how many incomplete outbound TCP-IP connections do you really need to have open inside of one second?

Windows XP, Vista, and Windows 7 are all DESKTOP OS, and the stated goal is to limit the spread of certain types of malware...

If you read the article referred to, the excessive outbound connection attempts are not dropped, they are delayed to maintain a manageable flow of information.

If I were to run a port scanner against a /24 subnet, that would mean it would take at least 2.6 seconds, since it would throttle the requests to each IP to a rate of 10 per second - what the heck is wrong with that? Must it be able to spew all 256 connection requests instantly?

A little research leads me to the conclusion that this is a meaningful effort to have a positive impact on the spread of malware on Windows XP, Vista, and Windows 7 desktops.

There is (was) also a limit on in-bound connections, made popular when Tim O'Reilly published a hack to turn Windows NT Workstation into Windows NT Server, allowing more than 10 in-bound connections, allowing companies to deploy lower-cost Workstation OS as web servers. Here is a brief recap of those events. [oreillynet.com]

Re:so.... (1)

mhall119 (1035984) | more than 5 years ago | (#27534957)

First off, how many incomplete outbound TCP-IP connections do you really need to have open inside of one second?

Eleven? Maybe twelve? I don't know, and I'm pretty sure Microsoft doesn't know either, so why are they deciding for me?

Windows XP, Vista, and Windows 7 are all DESKTOP OS

Oh, so that's a good reason to limit their networking potential? Every other "DESKTOP OS" can do more than 10.

and the stated goal is to limit the spread of certain types of malware...

Wow, security through....what, sloth? That's a new one on me.

Must it be able to spew all 256 connection requests instantly?

If that's what I want it to do, why shouldn't it?

A little research leads me to the conclusion that this is a meaningful effort to have a positive impact on the spread of malware on Windows XP, Vista, and Windows 7 desktops.

Perhaps a little more research is in order then. Not only does it not seem to be effective as stopping the spread of Windows malware, but not having this limit hasn't seemed to increase the amount of malware on any other OS.

Shit wifi performace is a standard Linux 'feature' (-1, Flamebait)

Anonymous Coward | more than 5 years ago | (#27527241)

You know it's the truth!

Re:Shit wifi performace is a standard Linux 'featu (1)

BPPG (1181851) | more than 5 years ago | (#27527481)

I know this is a troll, but I remember hearing someone say their wireless card works better on a linux driver than a windows driver. Unfortunately, I can't remember where, so no link. Will post again if I remember.

Re:Shit wifi performace is a standard Linux 'featu (4, Interesting)

KillerBob (217953) | more than 5 years ago | (#27527587)

*raises hand*

Intel 8945J integrated wireless on my laptop. Dual boot, Zenwalk Linux and XP MCE 2005. Until the most recent driver from Intel, the wireless card was *significantly* stabler under Linux. It's now just as stable under Windows (though I replaced by router with a new D-Link 802.11n router recently too), but the throughput at long range is still better in Linux.

As an example of the latter under Windows the useable range on my wlan caps out at about 25m. that's enough to cover my house, and much of the front lawn. Under Linux, I was able to connect to my network from the picnic table at the park across the street, about 100m. I was only getting 1mbit of throughput, probably less, but it was definitely getting better error correction and a more useable connection at that range than under Windows.

Re:Shit wifi performace is a standard Linux 'featu (1)

brusk (135896) | more than 5 years ago | (#27527861)

Where are your power settings in Windows vs Linux? My Thinkpad's Intel wifi driver defaults to an energy-saving power mode, which results in lower performance at long distances (but is fine in my small apartment). This might not be a fair fight.

Re:Shit wifi performace is a standard Linux 'featu (2, Informative)

Jah-Wren Ryel (80510) | more than 5 years ago | (#27528609)

Intel 8945J integrated wireless on my laptop. Dual boot, Zenwalk Linux and XP MCE 2005. Until the most recent driver from Intel, the wireless card was *significantly* stabler under Linux.

Who needs wireless - I've got an Atherlos L1 gigabit ethernet controller on the motherboard - despite it being years old, all vista drivers for it are dogshit slow AND crash under any significant load. Under linux it works just fine. For the one vista system I must run I had to waste as slot on a PCIe gig-e card and use that instead.

Re:Shit wifi performace is a standard Linux 'featu (2, Interesting)

DarkProphet (114727) | more than 5 years ago | (#27529109)

You know, I have noticed this with my laptop in my house. Under windows xp I get one bar of connection and its flaky at best. Granted this is on the other side of the house from the router and also on a different floor, so I am not surprised by that. But in the same location on the same laptop running an Ubuntu liveCD gets better signal and a much more reliable connection.

My guess is that the linux driver allows for a higher power setting, though over the years I've come to think that the Linux TCP/IP stack seems a little speedier than Windows... I dunno if that is really the case, but I like to think so :-)

Re:Shit wifi performace is a standard Linux 'featu (1)

gandhi_2 (1108023) | more than 5 years ago | (#27527601)

someone said something? oh...well then, that's a horse of a different color.

Seems like a lot of work (4, Funny)

seebs (15766) | more than 5 years ago | (#27527253)

Why not just use a Vista box and play an MP3?

Re:Seems like a lot of work (1)

Quantos (1327889) | more than 5 years ago | (#27527323)

You've noticed this too eh?
It does the same thing if you start Solitaire or Minesweeper.
I'm also wondering why this is news, I could understand it being in the Idle, but not the front page.

Re:Seems like a lot of work (1, Funny)

Anonymous Coward | more than 5 years ago | (#27527345)

Because that would take a good 4 or 5 hours to install.

But I guess MS would call that a strength of Vista: It takes hours to setup before it can fail while you can make Linux fail right away!

Re:Seems like a lot of work (1, Informative)

DrDitto (962751) | more than 5 years ago | (#27527683)

Funny. In 1996, my Windows NT 4.0 workstation box running on a Pentium 166Mhz machine would never skip playing an MP3 no matter what I threw at it. I could start 12 simultaneous programs and the WinAMP MP3 still didn't skip. I didn't get skip-free Linux MP3 playback until about 2002 with a 1.5GHz machine. Move a window, playback skipped.

Re:Seems like a lot of work (0)

Anonymous Coward | more than 5 years ago | (#27527885)

Funny. In 1998 my Pentium 133MHz could play mp3 just fine under Linux, except if I used Enlightenment instead of a more lightweight window manager. IIRC it didn't used to skip on OpenBSD either. Perhaps a sound card driver issue?

Re:Seems like a lot of work (0)

Anonymous Coward | more than 5 years ago | (#27527983)

Funny. In 1998 my Pentium 133MHz could play mp3 just fine under Linux, except if I used Enlightenment instead of a more lightweight window manager. IIRC it didn't used to skip on OpenBSD either. Perhaps a sound card driver issue?

Funny, my iPod never skips playing, no matter even if my notebook crashes. Syncing it under Linux is a pain for me however (I dual boot with ubuntu).

Re:Seems like a lot of work (1)

LoRdTAW (99712) | more than 5 years ago | (#27527887)

I believe the skipping is a limitation with X windows and not the Linux kernel. When you click to drag, the process that spawned the window is "paused" until you let go of it. This prevents X windows from going crazy trying to redraw the windows while moving which could cause problems. At least that what I read somewhere.

Re:Seems like a lot of work (0)

Anonymous Coward | more than 5 years ago | (#27528087)

No, I've seen the same thing he's talking about. You could move any window, not just the one playing the mp3. Even scrolling in the browser could cause playback to stutter, because the performance was shite.

However, for me that was using the non-Nvidia nvidia module. Once I got the non-free driver installed, there was no more problem.

Re:Seems like a lot of work (1)

uid8472 (146099) | more than 5 years ago | (#27528169)

The thing you read somewhere is wrong. There does exist the XGrabServer call, which some window managers use in some cases (mostly older WMs, I suspect), but the documentation strongly recommends using it as little as possible. In no case is anything like that inherent in X11.

Re:Seems like a lot of work (1)

BikeHelmet (1437881) | more than 5 years ago | (#27528399)

I've seen this behaviour too, on a board with a craptastic Via Unichrome Pro IGP.

I suspect something locks down the CPU while screen redrawing is occuring.

Re:Seems like a lot of work (0)

Anonymous Coward | more than 5 years ago | (#27534321)

Yep its a problem with X. Thats why until I had decent hardware, id open up a console and play mp3s from mpeg123. Still do to this day when I get sick of GUI annoyances.

Dude.. Is anybody here whining about W98? (1, Insightful)

Anonymous Coward | more than 5 years ago | (#27528259)

It's been 13 years. In Moore years that's a long time. Let it go.

Re:Dude.. Is anybody here whining about W98? (0)

Anonymous Coward | more than 5 years ago | (#27530443)

Yes, actually. Every Slashdot thread includes at least one whine about WinME and Win95, so why not Win98 too?

Re:Seems like a lot of work (1)

Lorens (597774) | more than 5 years ago | (#27528499)

You wanted BeOS . . .

Re:Seems like a lot of work (4, Funny)

Tubal-Cain (1289912) | more than 5 years ago | (#27528673)

my Windows NT 4.0 workstation box running on a Pentium 166Mhz machine would never skip playing an MP3 no matter what I threw at it.

Try throwing bricks.

Re:Seems like a lot of work (1)

alexandreracine (859693) | more than 5 years ago | (#27532753)

my Windows NT 4.0 workstation box running on a Pentium 166Mhz machine would never skip playing an MP3 no matter what I threw at it.

Try out the windows...

Re:Seems like a lot of work (1)

GuldKalle (1065310) | more than 5 years ago | (#27529951)

Yeah, winamp really didn't stop for anything back in those days. On my win9x-system it would happily play through some bluescreens as well.

Goal? (2, Insightful)

zombietangelo (1394031) | more than 5 years ago | (#27527281)

What is the point of doing this? Is this even of remote interest to anyone other than the author of the article? If there's a genuine reason for this to be important or at least intriguing, someone please speak...

Re:Goal? (4, Informative)

umeboshi (196301) | more than 5 years ago | (#27527327)

This seems to be valuable in situations where you are developing an application that will be accessing a database behind a dsl firewall. It would be nice to be able to profile the performance on your local network, instead of having it run too slowly to be used in the field. This happened to me once, and I fixed the problem by using a subselect, instead of multiple sql commands, but this wasn't readily obvious as the library was hiding the details of the process, and the speed of the local network compensated for the ineffiency(sp) of the code.

"inefficiency" (1)

jonaskoelker (922170) | more than 5 years ago | (#27529121)

compensated for the ineffiency(sp)

inefficiency, I believe. HTH.

Re:Goal? (1)

Haley's Comet (897242) | more than 5 years ago | (#27527399)

What is the point of doing this?

Actually, I was thinking of adding bandwidth throttling to certain parts of a subnet. This info is exacly what you need when you don't know where to start (for me at least).

Shit wifi performace is a standard Linux 'feature'

Com on now, switch distro's. How long did you research? Oh wait, your friend said "here, this is the distro for you..."? Try http://www.pclinuxos.com/ [pclinuxos.com] , or you could just accept that the US government has outlawed the OEM's of wi-fi from open sourcing the drivers. (some clueless dumbshit thought it would keep hackers from destroying infrastructure) This means we have to "wrap" or reverse engineer - so yeah, the drivers of most suck. Even though you were OT.

Re:Goal? (0)

Anonymous Coward | more than 5 years ago | (#27528185)

I use PCLinuxOS. I use native Intel drivers, no ndiswrapper, and seems to work fine on my Intel 3200BG WiFi card.

Re:Goal? (0)

Anonymous Coward | more than 5 years ago | (#27527413)

I've used this to help me design websites for bad connections by adding latency and reduced bandwidth. I already try to keep page sizes down, but it helps to see the website rendered as someone over a 56K modem would see it.

Re:Goal? (1)

phoebus1553 (522577) | more than 5 years ago | (#27527453)

Sure it is interesting. Lots of times you can't adequately simulate 'real world conditions' in an office LAN or even with consumer grade connectivity.

Example: At my job we operate a work-at-home business that transmits essentially a voip phone call from various locations of a certain restaurant chain to the worker's home over two dsl lines, but without the luxury of being able to 'redial'. The only DSL we can actually get in our office is too close to our datacenter (under 5 hops) to adequately simulate natural conditions.

We need to be able to make our solution able to cope with crappy lines and the only way to do that is by artifically generating latency. We had been using this old tech: http://www-x.antd.nist.gov/nistnet/index.html [nist.gov] but it is unmaintained now and while it runs well, finding a suitable distro to run it on is troublesome in the event our nist box ever kills itself or should another such dismal fate befalls it. This type of thing would be much better albeit w/o the pretty gui ;)

I'll definately be looking into the tc command more, I had examined it the last time I needed the test but somebody finally located the working nist box before I could get too deep in the man page.

Re:Goal? (1)

FooAtWFU (699187) | more than 5 years ago | (#27527571)

My company has a Linux box (named "slow-router") that does exactly that, to simulate network latency talking to remote devices over the network. I think it might even simulate random packet loss and such as well. It's useful to be able to do, but it's also not all that difficult... or newsworthy... good blog post, poor Slashdot post.

Re:Goal? (1)

phayes (202222) | more than 5 years ago | (#27530933)

I beg to differ, for me, this is geek news. I found TFA & the following discussion interesting. It touches subjects that interest me peripherally but that I never needed to research. Now, I've been able to discover some interesting tools it would have taken me a while to discover otherwise.

Re:Goal? (2, Interesting)

Orion (3967) | more than 5 years ago | (#27527643)

I just went through a similiar exercise at work, to determine if TCP was a good enough protocol for a slow point to point wireless connection with a high bit error rate.

We ended up using DummyNet on FreeBSD, mostly because we happened to have a high-end FreeBSD box handy...

Re:Goal? (1)

cheetah (9485) | more than 5 years ago | (#27527703)

This really is a something that has been around for a long time. One of the most interesting uses I have found for it is; simulating the effects of satellite Wan connections. Most of these links have about 600ms of end-to-end latency and without something like this simple tc command it is difficult to simulate this without actually hooking up to a real satellite connection.

Other uses; I once bandwidth limited one of my old roommates. Every week I would shave a little bit more bandwidth off of his connection. I think I started at about 500kbit and by the end of the semester I had him down to about 16kbit. We were waiting to hear him say something about the slow Internet connection. The whole time he didn't say a word and he just assumed that his computer was slowly dieing on him. ^^

Re:Goal? (0)

Anonymous Coward | more than 5 years ago | (#27532811)

Other uses; I once bandwidth limited one of my old roommates. Every week I would shave a little bit more bandwidth off of his connection. ...he just assumed that his computer was slowly dieing on him. ^^

You're kind of a dick.

Re:Goal? (1)

godrik (1287354) | more than 5 years ago | (#27527773)

well, tc is used on research grid on networking, tcp slow start, peer to peer simulation... It is clearly not new and I do not understand why this is posted on /. today...

Re:Goal? (1)

iYk6 (1425255) | more than 5 years ago | (#27528057)

I tried playing an online linux game called Daimonin. It is kind of like a multiplayer of the old Ultima's. AFAIK, it still suffers from a serious problem, in that it doesn't do any client side prediction, and so there is severe latency between every move and every action (about half a second, which makes the game too painful to play). I tried to fix it, and started by attempting to introduce some lag on my local connection, but didn't find a way to do it.

I have since discovered several methods of making a connection more internet like. Using iptables (or tc like in the article), you can introduce lag. You can also drop a certain number of packets, and cause UDP packets to show up out of order. I think a tutorial might be in order, as I was unable to find one years ago.

Re:Goal? (1)

RAMMS+EIN (578166) | more than 5 years ago | (#27528411)

``What is the point of doing this?''

What is the point of simulating a slow, lossy network? Why, figuring out how your setup would behave if it were in a real slow, lossy network, of course!

I use tricks like this quite frequently when developing network software and network protocols. Especially when I'm working on my forward error correction protocol, because that is _intended_ for slow, lossy networks. Alas, my Ethernet is very fast and very reliable. ;-)

Re:Goal? (1)

TheRaven64 (641858) | more than 5 years ago | (#27529387)

It is genuinely useful. One of the things I needed to do for my PhD was test a protocol I'd been designing in high-latency environments. For the early testing, I used the FreeBSD box under my desk as the server and my laptop as the client, and just told dummynet to add 100ms of latency into the connection. Later, I added some real world tests, but this was very convenient because the latency was entirely deterministic and so the results were reproducible. You can control latency, packet loss, and throughput (and jitter, I believe) like this, which is really great for testing how a protocol (or an implementation of a protocol) handles poor network conditions. I was testing with 200ms round trip time and 5% packet loss (which is what I get from a very flakey UMTS connection in a poor signal area), but with a lot more bandwidth than you'd be likely to get from such a link (the protocol was for a remote virtual memory implementation, where spare bandwidth was used for adaptive precaching and not having the required data already present on the client when it needed it completely killed performance. If you needed to ask for a retransmit over a 200ms delay before you did any processing, CPU usage on the client averaged to under 1%).

Re:Goal? (1)

bunratty (545641) | more than 5 years ago | (#27530135)

At my wife's company, most employees have Windows XP laptops and can connect to the file server at work using openVPN. Even though latency is only 40 ms, Windows XP is incredibly slow at accessing the file server. Even simple operations such as getting a directory listing can take several seconds. Opening a small Word document takes over 30 seconds.

If Windows 7 has a feature that speeds up this access, it's going to be of great interest to many people. Of course, if Microsoft fixed the poor performance of CIFS over high latency networks, it would be even better.

The truth is.. (1)

miknix (1047580) | more than 5 years ago | (#27527301)

that Linux is awesome for research!

so (3, Insightful)

Idimmu Xul (204345) | more than 5 years ago | (#27527315)

how did that windows caching stuff he was testing out perform? or is this article just a synopsis of the man page for a common command .... ?

Followup coming... (2, Informative)

rkhalloran (136467) | more than 5 years ago | (#27530151)

Author of TFA said his original intent was to highlight using Linux to simulate network crapfulness, but enough folks have asked your question that he's planning a followup with the actual caching results.

SCOX(Q) DELENDA EST!!

100ms (0)

Anonymous Coward | more than 5 years ago | (#27527335)

100ms of latency is a crappy WAN connection?

How spoiled we've become. 100ms was playable in Quakeworld.

Re:100ms (1)

Atti K. (1169503) | more than 5 years ago | (#27528997)

Yep. And latency is not everything. Bit errors, lost packets, out of order packets? That's a really shitty connection.

How about using FreeBSD instead? (0)

Anonymous Coward | more than 5 years ago | (#27527353)

FreeBSD's dummynet seems to provide something similar as well.

http://www.scalabledesign.com/articles/dummynet.html

WANem would have been better (1)

KrisJon (6582) | more than 5 years ago | (#27527393)

Re:WANem would have been better (1)

AcquaCow (56720) | more than 5 years ago | (#27527787)

WANem is a FANTASTIC product.

I use it heavily at work for generating latency into our net applications to see how they might behave across really shitty links.

It's great injecting out of sequence and randomly ordered packets at the click of a button =)

  -- Dave

Excellent tool for testing (4, Insightful)

hwyhobo (1420503) | more than 5 years ago | (#27527451)

Such capability is very useful to network folks to predict application behavior and best management approaches in various environments. We used FreeBSD for that purpose, but the effect was the same. We injected 350ms latency in each direction, and presto - satellite communication. That is enough to cripple TCP connectivity through a sizable pipe (latency will preclude the flow from taking entire pipe). By testing various acceleration methodologies, you can see first hand which one will allow you to fully utilize the bandwidth you are paying for, all in the comfort of your lab.

Re:Excellent tool for testing (0)

Anonymous Coward | more than 5 years ago | (#27528715)

With FreeBSD you can also use the pf firewall (which comes from OpenBSD). Pf allows an easy interface to ALTQ, which is a very advanced traffic shaper, so you can not just only add latency, but also simulate low bandwidth scenarios. It is also easy to simulate packetloss.

Besides pf and ALTQ, the IPFW firewall also offers some similar tricks.

Re:Excellent tool for testing (0)

Anonymous Coward | more than 5 years ago | (#27529659)

350ms for Satellite???? I wish

Pinging google.com [209.85.171.100] with 32 bytes of data:
Reply from 209.85.171.100: bytes=32 time=686ms TTL=235
Reply from 209.85.171.100: bytes=32 time=776ms TTL=235
Reply from 209.85.171.100: bytes=32 time=656ms TTL=235
Reply from 209.85.171.100: bytes=32 time=709ms TTL=235

Re:Excellent tool for testing (1)

hwyhobo (1420503) | more than 5 years ago | (#27529801)

350ms for Satellite???? I wish

Please read my original post again. I quote: "in each direction".

Re:Excellent tool for testing (1)

compnut125 (1171587) | more than 5 years ago | (#27533781)

http://wanem.sourceforge.net/ [sourceforge.net] is a great tool for this. We use it at work to test thin clients over simulated WAN links. It has a ton of options (latency, jitter, packet loss, bandwidth, etc).

That's nothing... (1)

creimer (824291) | more than 5 years ago | (#27527473)

Throw in a 300 baud modem [wikipedia.org] if you want a crappy network connection. You can read a newspaper (dead tree edition) while a screen of text is downloading.

Re:That's nothing... (1)

Bill, Shooter of Bul (629286) | more than 5 years ago | (#27528115)

I used to do something similar, with a couple of modems, a pbx, and windows internet sharing. That was my slow internet test for a while. Not 300 baud, but good enough for what I was doing.

Re:That's nothing... (2, Funny)

mazarin5 (309432) | more than 5 years ago | (#27528143)

I like how you felt the need to provide a wikipedia link, just in case we wouldn't know what that was.

Now if you'll excuse me, I think I hear some kids on my lawn.

Re:That's nothing... (1)

creimer (824291) | more than 5 years ago | (#27528271)

When I was a lead tester at Accolade/Infogrames/Atari (same company, two owners, multiple identity crises), I had younger tests who didn't think video games existed before the Playstation. They were amazed that I played Pong when it first came out. They were shocked when I introduced them to another tester who tested board games in the 1970's. You can't always assume that the youngsters know what you're talking about.

Besides, when was the last time you saw an acoustic modem? ;)

Re:That's nothing... (0)

Anonymous Coward | more than 5 years ago | (#27528423)

The TV show, VR-5.

Re:That's nothing... (3, Funny)

mazarin5 (309432) | more than 5 years ago | (#27528621)

They were shocked when I introduced them to another tester who tested board games in the 1970's.

Oh wow, so before video games people used to play with pieces of lumber? :D

Re:That's nothing... (1)

creimer (824291) | more than 5 years ago | (#27528731)

Sure. You take a couple pieces of board, and get a rope to tie each board to your feet, then pretend you're in blizzard trying to get home in chest deep snow.

Maybe do a google search... (1)

ockers (7928) | more than 5 years ago | (#27527525)

... and you might find out about NISTnet, which has been around for YEARS... NISTnet does the same thing as this, on Linux, and also includes a statistical latency delay model which simulates real world conditions.

Wish I knew about this earlier (1)

Reapman (740286) | more than 5 years ago | (#27527629)

At work we deal with satellite links in northern offices (100ms crappy? try 800ms... ), testing network apps and such it would be handy to have had this feature back when I did this sorta thing.

Good to file away in the back of my head for future reference.

used it (1)

mapleneckblues (1145545) | more than 5 years ago | (#27527633)

tc basically allows you to activate netem (a network emulator in linux). I dont know about now, but when I had used it for a project a year ago, you had to compile your kernel with netem enabled. tc then allowed you to modify your link properties to emulate wan links. Had used this with tcpprobe to analyze the performance of an Inverse Increase Additive Decrease congestion control algorithm that we had written for academic purposes (adapted from http://nms.lcs.mit.edu/papers/binomial-infocom01.pdf [mit.edu] ) and compare its performance with newreno. Fun stuff. This was a helpful reference: http://linuxgazette.net/135/pfeiffer.html [linuxgazette.net]

FreeBSD kernel has had this since 2002 (0)

Anonymous Coward | more than 5 years ago | (#27527671)

The "dummynet" functionality in the FreeBSD kernel has provided this for years. Works like a charm.

http://www.freebsd.org/cgi/man.cgi?query=dummynet&sektion=4

http://info.iet.unipi.it/~luigi/ip_dummynet/

Wanem... (1)

HockeyPuck (141947) | more than 5 years ago | (#27527943)

Try using Wanem http://wanem.sourceforge.net/ [sourceforge.net] You can even download it as a vmware virtual appliance.

Quality reporting (0, Flamebait)

timmarhy (659436) | more than 5 years ago | (#27527959)

this is the kind of quality stories i've come to expect from kdawson/timothy.

and you wonder why we all choke with laughter when you expect to be considered journalists.

Re:Quality reporting (1)

KiloByte (825081) | more than 5 years ago | (#27528855)

and you wonder why we all choke with laughter when you expect to be considered journalists.

Have you ever looked at the quality of regular journalists? If kdawson/timothy make an error, it is quickly pointed out by the readers. Traditional journalists? Same or worse error rate, no corrections.

Lanforge (1)

Piranhaa (672441) | more than 5 years ago | (#27528543)

Though not free (there is a trial), I played around with an appliance with a program called Lanforge installed. It's pretty sophisticated. You can setup a number of different "errors" (packet loss, jitter, delay, etc) and it can cycle between them - never constantly the same. It runs on Linux and Windows for sure, but I'm unsure about other OS's. It will also "learn" link statistics between two particular nodes and save that configuration for testing.

Kind of neat, but I'm unsure about how much license costs are. There may easily be open source applications that could be just as good.

Link is here: http://www.candelatech.com/ [candelatech.com]

I needed some relief. (0)

Anonymous Coward | more than 5 years ago | (#27529009)

So I abused myself last night.

Can I get some mod points for letting the world know ?

However, he is a *spoiled* Windows fanboy (2, Funny)

K. S. Kyosuke (729550) | more than 5 years ago | (#27529193)

...as demonstrated by "VIM rocks" in his text.

Is there nothing Linux can't do ... (1)

Wicknight (671279) | more than 5 years ago | (#27530087)

Amazing, Linux can mess up my LAN. Next you will be telling me it can make me bald, fat and unattractive to women ...

I just used sleep(millis); in my program... (0)

Anonymous Coward | more than 5 years ago | (#27530837)

Can I be on the front of Slashdot too!?

Reboot? Why? (0)

Anonymous Coward | more than 5 years ago | (#27534047)

# Once my newly minted Linux box was up and running. I then configured the network properties and enabled IP Forwarding (VIM rocks, I always really hated VI): (Edit the /etc/network/interfaces file for the network settings and Edit the /etc/sysctl.conf file to turn on net.ipv4.ip_forward)

syctl -e net.ipv4.ip_forward=1

# I then rebooted the Linux box, and once it was back online I verified that it was able to act as my router between my two previously mentioned network segments.

Seems un-necessary.

Load More Comments
Slashdot Login

Need an Account?

Forgot your password?