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Traffic Shaping on DSL?
jackla asks: "I'm now looking for software to do traffic-control on my Windows XP box. I am connected with DSL and my upstream is capped at 96kbit/s (down is 1.5Mbit/s) - this means that high(>70kbit/s) upstream utilisation KILLS my downstream: it just drops down to about 400kbit/s and stays there unless there's more upstream space. That said, I read alot about the Linux shaping solution (wondershaper or something) which sounds exactly right, except I need something that works for Windows. What I want to do is prioritize upstream ACKs (for example) so that my downstream isn't affected by upstream use.
If anyone heard of a peace of software that can do this, I would love to hear about it." It would be nice if something like this existed cheaply for Windows. I am unaware of such, but maybe a few of you have ideas. Could such a traffic shaper be built using low powered computers? If so, how would you build and configure it so it would maintain compatibility for the single Windows machine, behind it? (Think: homebuilt traffic-shapping appliance)
Are you a server, business or home user? I understand that you want as much bandwidth as possible, but if you are just a home user, 400 kbit down stream is not bad at all.
To answer your question directly, my solution would be to buy a cheap box (like say, the Mandrake boxes from Wal-Mart) and use it as your traffic shaper. Linux products for this are much cheaper than any (useable) solution you can find for windows.
There is nothing wrong with being gay. It's getting caught where the trouble lies.
I have DSL through Telus in Canada with the same upstream cap, and high upstream utilization means a very, very minimal hit to my downstream speed. Perhaps it is more of a hardware issue than anything else? Or rather, something that you should be asking your DSL provider about instead of the general Slashdot community? *shrug*
LRP's project might be of some use. Yes, it means getting a cheap box to run Linux, but then you can use all of that real neat networking software that's available for Linux boxes but isn't available for Windoze boxes.
Not everything that can be measured matters; Not everything that matters can be measured.
We want some answers and all that we get
Some kind of shit about a terrorist threat
- Ministry
If you're using Linux on the firewall machine, make sure you enable QoS and ALL the modules in it. Then grab cbq.init and set up the traffic shaping rules. The script file is well documented.
-F-
... has a Tweak Test that tests some connection settings such as your RWIN. I had the exact same problem as you and it turned out that my RWIN was set wrong and once I fixed it, the problem pretty much went away. Try it and I bet it helps.
I'm a minister!
If you know the Linux program, why don't you just use Linux for the network controller? Have the Linux box be used as a gateway, running ipchains and the wondershaper. Linux is not that hard. Linux can also be run on an early machine. I am running Red Hat 7.2 on an AMD 133 with 48 mb of ram. I am running in command line, which is hard for a beginner to learn, but it is running dhcpd and Samba nicely. I would recommend Linux because security is easier to setup and maintain than Windows. Windows you will never know what ports are open or who is watching. Linux you can close ports alittle easier, much better for server (or routers/gateways). Why Live on Windows? Most of the programs you need for network admin are free.
Linux, because Windows XP is eXPerimental!
what is going upstream from your pc. You can download an eval. version of Iris ( a sniffer ) and see the traffic originating from your pc destined to outside your network.
You might find something crazy going on because a non-serving pc should be pretty quite. You will see broadcasts and ACK's but thats normal. If your computer is spewing traffic and you can't find the source your NIC could be off in the weeds or you may have been hacked (not uncommon with windows and DSL/Cable). I have 38 IP's in hosts.deny because of detected port scanning on my DSL.
I came to the datacenter drunk with a fake ID, don't you want to be just like me?
I believe XP comes with the "QoS Packet Scheduler" and has it installed by default. I believe it can do what you ask.
Could such a traffic shaper be built using low powered computers?
Fire up that 90MHz Pentium, install FreeBSD, and build a kernel with bridging and dummynet enabled. Dummynet is an awesome network simulator. Just set up a couple of ipfw rules for the types of traffic you want to limit, and then set the bandwidth parameters in dummynet. It's very easy to do basic stuff like you're describing, but you can do all kinds of other things with dummynet... latecy, loss, queue limits, simulating multiple hops and multipath links with different latencies. There are no tools of this caliber (let alone free!) for Windows.
Next question?
I don't see what you are getting at.
Rather, I think I see what you are getting at, but I think the assumption is flawed.
Full use of your upstream should NOT be crippling your downstream so much, that's not how it works. TCP should adjust accordingly.
Having same problem I've attempted to use
ALTQ with openBSD. It did not work since
they do not work well on slow speeds (below
8Kb/sec).
Linux has rather impressive QoS facilities (so many options that it has an entire submenu in menuconfig). What you'll want is some floppy router distribution (mine's not quite ready yet, but I hear LRP has most of these options) and a decently powerful machine (100-200MHz pentium with 32-64MB should PLENTY for a DSL, but remember, you're not just routing/NATting).
There are tons of preconfigured things out there, but you might want to read up on tc (the traffic control manipulator, part of the iproute2 distribution), ip (from iproute2) and iptables (to help classify packets) before you dive in. The kernel ships with most of what you'll need (including the common CBQ scheduler), but there is a really cool scheduler known as HTB that is more accurate because it's resolution is traffic based, not time based. If you want to shape inbound traffic destined to teh router itself, you'll also need the IMQ patch.
Hope this helps. If you want more info, EFNet #iptables, look for KurD, the human router. He plays with this stuff all day at his job.
--MonMotha
Unfortunatly this won't help him. The QOS packet service is designed primarily for audio/video applications and would require that every router he connected through strictly obeyed the 802.1p protocol. That is just not going ot happen.It also requires a heck of a lot more then just clicking that little check box on the XP client. You can just consider that an on/off switch, the real work is done at the server and endpoint router levels.
h tml.asp?ID=1674
Have a look at this link for some futher explaination. http://infocenter.cramsession.com/techlibrary/get
If you wanna get rich, you know that payback is a bitch
When I was designing support for discarding packets in a BRAS (Broadband Remote Access Server), I put in support to prioritize control packets (i.e. tcp ACK over data packets to try and make this a lot better. A BRAS is a box that sits at the other end of a DSL modem and terminates PPP and PPPoE sessions (and more). This would only affect traffic going to the end user since the upstream traffic is usually shaped in the modem. I put this in specifically to deal with the problem you describe. I ran into the same problem when @Home reduced the upstream bandwidth to 128Kbps from 1Mbps. I did some shaping on the software running on my computer which helped a lot, but most users don't have that flexibility.
The box I'm working on supports tens of thousands of simultaneous DSL users and can shape and buffer each user's traffic independently, going so far as being able to shape individual traffic flows to and from a user. It's also designed so that a user can change the amount of bandwidth they want on the fly and letting the ISP choose how to charge for this. This also allows for things like downloading video on demand, where the pipe from a video server to the subscriber can guarantee bandwidth for that flow.
As for shaping traffic in Windows? I havn't a clue. I don't do Windows.
This post is encrypted twice with ROT-13. Documenting or attempting to crack this encryption is illegal.
I forgot to add-
In this case "run linux" or more appropriatly, run an additional machine that runs linux would be in all likelyhood the right answer for this situation. Other options are probably way too expensive.
If you wanna get rich, you know that payback is a bitch
Unless I'm mistaken, that won't hlep.
What the QoS scheduler does in windows is permit applications who specifically request a certain qos to keep it. Í don't think it's a robus, configurable queuing system.
Bandwidth Limiting HOWTO might be of some assitance? Or not... either way. It just caught my eye on linuxdoc.
python -c "x='python -c %sx=%s; print x%%(chr(34),repr(x),chr(34))%s'; print x%(chr(34),repr(x),chr(34))"
Might be nice as a "off-the-shelf" solution (if you have a rack), but - as you say - probably cost-prohibitive. A Linux box would be a much cheaper option for a "homebuilt traffic-shapping appliance".
Not everything that can be measured matters; Not everything that matters can be measured.
So yes, traffic shaping can be your friend. Unfortunately, it may be hard to know what to tune it too, depending on where the bottleneck is.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
Okay, here's the issue. I've set this up myself, and there are good HOWTOs on it, and I've done a bit of testing. First, the problem is not prioritization. The packets are leaving the XP box in perfect order. The problem is that the cable modem has a ridiculously large upload queue, which fills up. Packets then take a hell of a long time to get through. You just want to cap the outgoing data rate *at your computer* to just below the cable modem limit, which keeps the buffer from filling up. You can play with prioritizing various packets if you want, but it doesn't do much of anything for me. The data rate cap massively improves download rate.
Honestly, I'd just get an old box and set up a nice Linux router/mail server/whatnot, which will give you more flexibility and if you decide to add more machines to the network, not require you to have your workstation up 24/7.
May we never see th
This could be an interesting feature to add to their already EXTREMELY USEFUL "Cable/Dsl Routers"
:)
Linksys managers listening??? Get your engineers working on it.
Linksys recruiters listening??? I have several other ideas that would be nice to incorporate and since I'm a college student I'd rather not give them away for free
I've been running BBIagent
http://www.bbiagent.net
for about the last year or so. I share my DSL with a few neighbors via some cat5 we strung up over the last year, and my counterstrikin was startin to hurt real bad whenever one of the teenager kids was downloading from kazza
Before I was using a linksys router. My current BBIagent setup is a packard bell p60 with 32 megs of ram, and 2 old 16 bit isa 3com nics. The performance increase is stunning.
You can specify what kind of traffic to create priority for, forward, block ports. There are a few options for hack detection blocking. The nicest features of bbiagent is.
1. Single floppy distro which is configured on the fly via the bbiagent website
2. Java app for admining the sucker, very well laid out.
3. Realtime control over your network connection without losing it. On my linkstink whenever I would change a rule or a forward the whole thing would reboot itself, bbiagent doesnt do that.
4. Open source!
5. Linux Based!
I can go on and on about it, but if you're really looking to control what and how packets are handled, I would really recomend giving bbiagent a try.
--toq
The reason your downstream rate gets limited by your upstream rate limit is because of your inability to send acknowledgements upstream for the downstream packets you are receiving because of the congestion on the upstream link.
Once the advertised receive window is filled with packets, the remote side is not going to send any more data until it gets an ack from your computer.
At the point that the rate is being limited, the way to fix this is to give preference to ACK packets -- i.e. packets without payload.
The problem is that this has to be done at the point the rate is being limited, which is at your providers router, not at your router, and not at your Windows machine.
Installing the Microsoft packet scheduler, or some UNIX box with a real netowrking stack that you can exercise fine control over packet priority, as some people have suggested, isn't really going to fix your problem, except by maybe 10% (the exact amount depends on your average outbound payload size relative to an "empty" ACK-only packet).
This is because the problem is the queued data in the transmit buffer in the rate limiting device not containing your ACK's for inbound data.
Really, the TCP/IP protocol wasn't built for asymmetric reates, without equally asymmetric data transfers.
Effectively, you need to be able to control the transmission of data packets from your end based on knowledge of how full the input buffor on the outbound leg for the rate limiting device gets, so that you can throttle your data payload packets accordingly, to keep that buffer as empty as possible.
The only way you can really do this is to put code in your stack to monitor the advertised window from the other side, and the locally classify outbound packets as to whether or not they contain data payload, or are merely acks. You basically have to avoid filling the outbound queue on the rate limiter above 50%.
In an ideal world, the machine doing the rate limiting would do this for you. Some rate limiting machines for asynchronous connection do this, and it's not a problem (you can see the posts from the people who are rate limited, and don't understand your problem). But those machines are more expensive, and it's just as well for the provider if you feel pain as feedback for uploading, since it serves their purpose in providing you asymmetric service in the first place.
The problem's a lot easier when you are trying to avoid filling the inbound receive buffer for a router with a speed differential on one side (e.g. the inbound receive buffer on a router connected to a dialup modem bank, with a customer on a modem wanting to do QoS based on protocol type, so their SSH didn't lock up when an FTP or large HTTP transfer started up). *That's* where things like "AltQ" and the Microsoft packet scheduling engine become useful... not here.
-- Terry
I dunno. When I hear stuff like this is think of what happens when you start running traffic through a full-duplex NIC on a half-duplex LAN. If a full-duplex machine on the network starts sending/recieving traffic from the net, it's gonna seriously affect your throughput. I always suggest that people check through all their machines for full-duplex OR 100Mbit when using a 10M hub or a low-end 10/100 switching hub.
I am MuchTall
You're correct, there IS a fine line between support and discussion. With support, the same issues appear again and again. With discussion, an issue is talked about once, and never appears again unless there's new information.
Personally, I think that Traffic Shaping is a fine topic for discussion. If it also answers someones technical question, then all the better! But if this topic appears again in the next few months, though, then that has stepped over the line.
Try changing your local TCP buffering parameters instead to allow a bigger receive window. Set DefaultRcvWindow to something like 32768; the default is 8192, which is low for a DSL line, especially one that asymmetrical. With a bigger setting, you can have more data in flight, which makes the TCP connection more tolerant of delays in ACK return.
Given the numbers you're reporting, your ACK delay isn't that severe. You're only losing 2/3 of your downstream bandwidth. So quadrupling the amount of data allowed in flight should overcome that problem. Prioritizing your uplink traffic should be unnecessary at this time.
A real question to ask is "why are you trying to run a server on a 96Kb/s line". Buy hosting from somebody; it's cheap and they'll have far more bandwidth.
There has been an extremely large number of trolls lately, and, as these answers suggest, very little useful information. This may in fact be a hard question, but must we compensate ignorance with stupidity?
"She's a scientist and a lesbian. She's not going to let it slide." Orphan Black
You can play with these settings to get the best performance, but in general these should help out some.
c es\Tcpip\Parameters
e ntVersion\Internet Settings\
Note that, at most, simply disable then re-enable the network adapter in question. No rebooting should be required to make any of this take effect.
Keys: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Servi
GlobalMaxTCPWindowSize:DWORD = 256960
This should be a multiple of MSS, which is generally MTU - 40. Best results - pick a multiple of MSS lower than 16-bit (65535) times a scale factor that's a power of two. In other words, pick any multiple of MSS as long as it's under 65535, them multiply that by any power of two to arrive at the TCP Window size (RWIN).
Tcp1323Opts:DWORD = 1
This enables RFC 1323 options, which allows for a TCP RWIN greater than 64k. If you don't do this, most of the other settings are bunk as they will be limited by the 64k RWIN value.
EnablePMTUDiscovery:DWORD = 1
Enables automatic discovery of the MTU for your line, with the MSS set appropriately. You can set this to "0" to force your own value (see below).
TcpMaxDupAcks:DWORD = 2 (range from 1 to 3)
Number of duplicate ACKs recv'd for the same seq number of sent data before fast retrans is triggered.
NOW on to the MTU: it must be set on a per-interface basis. Find your TCP/IP interface associated with your NIC under Parameters\Interfaces\
MTU:DWORD = 1500 (probably... depends on your provider.)
On an unrelated note, you can force IE to hit up a web server with more connections than normal, which can help web pages load more concurrently.
it's under HKEY_CURRENT_USER\Software\Microsoft\Windows\Curr
MaxConnectionsPerServer:DWORD = 20
MaxConnectionsPer1_0Server:DWORD = 20
First is HTTP1.1+ servers, the other is HTTP1.0 servers. Specifies the max # of connections IE will open to a single web server in the process of downloading a page.
Natural != (nontoxic || beneficial)
Currently I have a 128K/128K connection, I wont let the family touch the idsl when Im playing games. But if there was a way I could limit them to like 24K MAX during my games, I could get away with it.
Anyone know if this will help on a low speed dsl?
I believe you are using a commercial OS, so there must be a way they can help you. At least I think a great support system must be reason you are paying for your OS, isn't it?
Good luck
My router (Netgear RT314) has a telnet screen that displays through (Tx & Rx). I haven't checked with my new 1184/160 G.Lite DSL connection, but with my old Nortel (unknown standard) 960/120 I saw this problem. When I was downloading at full speed (105kB/s), I saw 3-4kB/s upstream activity, which was in excess of 20% of the upstream bandwidth. No wonder that fast uploads choked concurrent downloads. I increased my RWIN, but I don't want it above 32K. Unfortunately, this didn't have much affect.
I think the situation is made worse when the DSL line is set for interleave rather than fast path. On my line, the first hop latency with interleave path is about 70ms, and fast path it is about 10-15ms. I know this because my telco recently tried to switch me over to fast path, which resulted in 40% packet loss due to a higher communication error rates with the modem and the other end (DSLAM port?) at the CO.
This excellent paper (PostScript format) describes some of this, and in particular, interleave path vs. fast path.
Um, what I'm getting from this thread is, what he wants doesn't exist. Advice I always give anybody asking my opinion on what to buy is; define what you need to do and buy the hardware/software to do it. For some people that means a Windows machine for games, others it means Linux for a robust web server, others it means a MAC for desktop publishing (don't flame, Windows DTP has come a long way). I never recommend a brand, hard drive size, memory size, platform, etc. As you noted there is lots of platform specific solutions being recommended. Weed those out and see if there is any workable Windows solutions. If not, he may need to find a platform that will run a suitable application for his needs. In this department there seems to be lots of endorsements of a reliable solution that works.
The truth shall set you free!
The best thing he can do is either:
- switch to a better ISP
- Use another box to run a unix based OS with a better suited QoS/packet scheduler/shaper combination on it and have that provide the routing/natting for his home network.
The second approach might set him back a couple of bucks, but he'll get so much in return.The benefits outweigh the drawbacks.ADSL is duplex.
ADSL works by dividing the usable range of frequencies on your phone line into segments.
Lets say that your analogue phone line can support transmission to the local exchange of frequencies from about 0 to 1100 Khz (or there abouts) over copper. The bottom 4Khz is reserved for voice. (I dont know if voice is compressed, I suspect there is some sort of companding in action to give a wider actual response but I dont know.. but the frequency range is adequate.) Then there is a band from about 30Khz to 140 Khz that is used to support the upstream channel, and then frequencies above that out to about 1100Khz are used to support downloads. There is a gaurd band between each band that eliminates crosstalk induced by imperfect transmission conditions.
This arangement gives you 256Kbps Up and 1500kbps down. Filters are used to isolate the appropriate channels at either end for voice, upload, and download. But the point is that its duplex by design, singnals go both ways SIMULTANEOUSLY over the wire. Remember that ADSL transmission is analogue, thats why you have a MODEM (its an acronym, not a noun!)
So as has already been explained by previous posters, the most likely problem is that as you flood the upstream channel, your ACK packets are being queued, the network devices upstream then start to throttle back your downstream feed, as the ACKs are taking too long to come back. This is done to minimise the number of packets that will be dropped and resent to your address. Of course you arent dropping any packets , but the upstream devices dont/cant know that.
Anyway hope that helps. The July 2002 edition of Australian Personal Computer has a lovely graphic that explains how ADSL works and why you can use your phone and have a nice broadband connection at the same time. Unfortunately this article isnt on their site http://www.apcmag.com
Cheers
Micko
You want it cheap on windows too?
Your mission for this year:
- Become proficient in C.
- Port what you need from Linux to Windows (you suggested Linux already does everything you need).
Problem solved.
And sorry to say this, but 99% of the time this is the only way software becomes "cheap", is when someone who wants some software but can't/won't pay for it creates it (or ports it when available). Maybe you'll get lucky and it'll be ported for you, but I doubt it. Its just far easier to set up a linux router for this sort of thing.
Unfortunately, windows is well known as one of the world's biggest "pay" OSes. You just won't find much free (of consequence) for it that didn't exist on another OS first -- even taping a simple phone conversation will cost far more in software than hardware (source: The Screen Savers).
I wish you good luck on your search, though!
If you could be told what you can see or read, then it follows that you could be told what to say or think - BoC
I was running this on old 386 and 486 machines with 8MB ram, though I think the newest releases require a little more ram (more ram would also allow for more firewalling rules).
T
Support TBI Research: http://www.raisinhope.org
I have pretty much the same problem, and it looks from the posts so far that there isn't any existing solution to do queueing/shaping on XP... Does anyone know where to look for documentation for how you would write a program to do this? What API do windows software firewalls use to intercept packets? I've looked around MSDN a bit, but didn't find anything, is there an unofficial guide somewhere?
--
Benjamin Coates
The Wondershaper is really great. I use it on my ADSL capped at 650kbit upstream and ~475kbit downstream. Without it my ping times when uploading the full 650kbit is >500ms but with wondershaper it's 10-20ms (with a very small speed hit). Full download brings ping times around 100ms, and full speed uploads *never* hurt downloads at all.
His upstream is 96Kbit, and his downstream is 1.5Mbit.
In round numbers, this means his upstream is slightly less than 1/16th his downstream.
Say his MTU is 1500 bytes. Let's say his ACK packets are 64 bytes (we were generous on the 1/16th, so 64 instead of 60 is not that far off).
That basically means that, assuming no packets are lost, and that all ACK packets are precisely equally spaced, then 2/3rds of his upstream bandwidth needs to be dedicated to ACK traffic for the downstream bandwidth.
Why do we have to assume equal spacing? Because he can't control anything other than his send order, because he can't control the rate limiting machine's discard.
Is it possible to do this with a traffic shaper on the client machine? Yes, with a very sophisticated traffic shaper, which maintains stateful information (e.g. like a PIX firewall maintains per connection state information). It's possible because now we know the numbers for his connection -- we don't know the general numbers, though, for *any* assymetric link, so this isn't something you could make into an installable package, without the user having to resort to math/tuning tools.
Even so... this only works if the traffic is connection oriented. So far, people have asked -- and he hasn't responded -- about the kind of traffic he's running.
If the download traffic is RTSP or UDP or any protocol based on packets other than TCP packets, then there's no way to make preference choices on packets sent out. And then he's back in exactly the same boat he was in before.
So it's not possible to say "install this", and it's not possible to say "install this, and set these tuning values based on your relative upstream and downstream speeds", unless you really limit the problem you are trying to solve.
Doing that will probably not be satisfying, since the primary reason for a (mostly) unidirectional pipe is to push content to users, and most content streaming protocols are not based on TCP or other things which can be stateful.
-- Terry
For those interested in knowing how to tweak your ADSL, cable modem settings in Windows, the following link contains excellent and comprehensive information on how to achieve peak download speed: Navas Cable Modem/DSL Tuning GuideTM
¦ ©® ±
You might want to have a look at the following projects:
Traffic Control - Next Generation
Differential Services
GTC - A Graphical frontend the Linux kernel Traffic Control
WRR and WIP
And, yes, those are all Linux solutions, but that's simply because that' all I found available without paying 20.000 dollars.
echo '[q]sa[ln0=aln80~Psnlbx]16isb572CCB9AE9DB03273snlbxq' |dc
You don't need traffic shaping. Just make sure your TCP receive buffer size is 15 time larger than your TCP transmit buffer size, and the ACKs will be sent in a timely manner.
Works perfectly for me. Disadvantage is, that this is a setting you must set on all machines.
The latency is -- most likely -- caused by the huge buffers in the modem. It *is* possible to improve the situation locally. It's got nothing to do with asymetric lines or somesuch.
It's simple: what happens is that the upstream buffer in the DSL modem does'nt prioritize traffic at all, most likely it's just FIFO and big. So if the buffer is 128kB and you're serving a big file, your next Telnet packet is going to have to wait for these 128kB to go up before going itself.
The solution: have a router that artificially limit the outgoing bandwidth to slightly less that the DSL line permits to make sur the modem's buffer never fills up. Then it's the router's buffers that are filling up; but your router is smarter and you can have it order packet. IE if you have 128kB worth of warez0r waiting to go up, it can decide to let that lone Telnet packet go first.
Me I installed Wonder Shaper, works very well esp. when you've identified what causes the contention (just add the relevant ports to the junk traffic list), even if I completely saturate the link. There's one thing that doesn't work tho: I discovered that at times I had huge ping, again, even with wshaper. What happens (*I think*) is that my ISP is getting overloaded at times, and my actual bandwidth goes below what I set it to in Wshaper. I have to find a way to improve this.
He's running an fserv on irc.. His problem is he can't download pr0n fast enough while sending enough to meet his quota.
If voting were effective, it would be illegal by now.
"By increasing the recieve window you are essentially reducing the amount of ACK's that must be sent per data recieved."
The problem with this theory is that you need to keep sending ACKs all the time to keep the window sliding. Yes, if you were to only send ACKs starting at 50% of the window size received, and you had a large enough receive window that the propagation delay for an ACK through a totally saturated link was less than 50% of the time necessary to receive the data being ACK'ed, and the rate limiter queued all packets, instead of just droping them, then you'd be right.
But that's not what you do.
The point of a windowed protocol is that you eat a single round trip latency over a very large data stream consisting of a large number of packets, and what you are saying is that it will act as if TCP/IP is a lock-step fixed window protocol. This just isn't true.
So you compete for transmit space with the same number of ACK packets.
The problem is still that you need 2/3 of the send bandwith just for ACKs on a saturated receive bandwidth.
I would be really surprised if the send bandwidth limit wasn't set with *exactly this* in mind: large enough to handle full speed receives with an MTU of 1500 and an ACK packet size of 60 bytes, plus 50% (1.5Mb/96Kbit = 16, 1500/60 = 25, 25/16 = 150%).
-- Terry
Like others said, get a cheapo box throw two ethernet cards in it, load Linux, and use it as a router. I have this setup myself, along with 4 Windows machines behind it.
Believe me, I sleep better at night, knowing that I have Linux between the Internet and my Windows boxes. There are a number of good firewall/proxy/router tools for Linux. You can then use the traffic shaping software, and more importantly, you don't have to worry about the constant security weaknesses found in Windows that make your machine an easy target for hackers.
Now that's a really pathetic way to put down someone's opinion. especially when it is so ontopic.
I will so metamoderate that person into non-moderation.
Posting this at +2 again so people can read it:
ou want it cheap on windows too?
Your mission for this year:
- Become proficient in C.
- Port what you need from Linux to Windows (you suggested Linux already does everything you need).
Problem solved.
And sorry to say this, but 99% of the time this is the only way software becomes "cheap", is when someone who wants some software but can't/won't pay for it creates it (or ports it when available). Maybe you'll get lucky and it'll be ported for you, but I doubt it. Its just far easier to set up a linux router for this sort of thing.
Unfortunately, windows is well known as one of the world's biggest "pay" OSes. You just won't find much free (of consequence) for it that didn't exist on another OS first -- even taping a simple phone conversation will cost far more in software than hardware (source: The Screen Savers).
I wish you good luck on your search, though!
If you could be told what you can see or read, then it follows that you could be told what to say or think - BoC
Comment removed based on user account deletion
> Full use of your upstream should NOT be
> crippling your downstream so much, that's not
> how it works. TCP should adjust accordingly.
TCP normally piggybacks ACKs. That is, an ACK is sent out on traffic going the other way on the TCP connection. So, if there were only one connection, this isn't a problem.
The problem lies in asymetric TCP sessions (huge data-filled going upstream with virtually data-less ACK packets coming back) over a congested upstream link. When your upstream gets saturated, the ACKs get caught between huge packets from whatever other traffic). Cable and DSL modems, for example, have a huge queue, so it is easy for your entire TCP window of ACKs to be waiting in queue. The lack of ACKs causes the remote end of the stream to pause sending and kills your throughput.
In short, TCP is tuned for lower bandwidth links. Applications like satellite connections (where there is huge bandwidth but huge latency) could really benefit from insanely large windows, but you just don't see it much yet.
I think Mauve has the most RAM. --PHB (Dilbert Comic)
I agree but there are very few games to play on my Linux machine and even FEWER people worthy of playing against. I use Linux for a dedicated server for UT, NWN, Quake, and as a firewall/email server, but I like to play NEW games, and I am NOT a coder, so waiting for someone talented enough to port the games really SUCKS :( :(
I look forward to the day when games are coded for Linux before release. I payed for many Loki titles even though I'd played the games to death on my Windows machine just to try and help, poor investment strategy
errr....umm...*whooosh* *whoosh* Is this thing on ?
Modems have start and stop bits on them. Yeah, OK, cable modems, so I should have done 8-bit bytes :-) DSL doesn't have them either, but DSL does have ATM headers which add about 12%. But even 64kbits takes half a second on your 128kbits upstream, which can easily annoy your downstream traffic.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
What are the best oranges to grow in California?
and you respond with
You should move to Florida, you can grow much better navel oranges there.
The future isn't what it used to be.
If you ask specific questions, I'll try to answer in laymans terms, if you are genuinely interested.
If you aren't interested in laymans terms, and it's just that I'm not a very good explainer (8-)), I can give you references to technical papers.
-- Terry
Actually, I was quite surprised the other day. I actually used a built in modem on my laptop to dialup to check mail and download something I had to have at that moment. few megabytes download started, and I was actaully able to type over ssh link almost laglessly while the download was going at about 2.7k/second or so (this is a modem remember). And I remember on linux, if I didn't throttle the download using some download manager, things would get so laggy I had to wait like 20 seconds to see what I typed over ssh session. Surprising that the same kind of stuff doesn't work with DSL modems...
Damn Speakeasy won't even talk to me about what line speed I can get until I have severed my contract with Megapath ?!?!?! What a crock, what if they can't or won't support the set-up I have now, it will be to late then. I'd like to look into them but this kind of scratch the other ISP's back BS makes me ILL. It's my line but they can't talk until Megapath releases me ?!?! Fark em all
errr....umm...*whooosh* *whoosh* Is this thing on ?