yea a cap is a cap, if you read the sticky http://testmy.net/topic-2097

you will see that i suggest to tweak if you cant reach 90% of cap  ;)

VanBuren

yea, sometimes there is systemwide issues that need to be fixed, no tweak can fix a overloaded node...

you are very incorrect when you claim "A properly set up system (clean) should never need a "tweak" to get  normal bw out of a modem."

may i ask where you got that information?

VanBuren

Personal experience having built hundreds of pcs AND was a Comcast Contractor installing HSD for about one year.......

If your line is good to the house and the pc is in normally even fair shape you will bump against your caps..

I know my 3.2 test doesnt seem high,, but I am on a 3.0/256 cap right now...No tweaks..

I live in the boonies and wont see the upgrade till the last  (on Comcast)...

Where do you get your opinion?

( of course I wired my own house with a home run about 15 ft from my drop .....)

building pc´s wont help your connection to go faster  ;)

take a good look around this place and see what tweaks can do to your system

here is some teory about RWIN and why you need to change it sometimes...

quote from http://www.psc.edu/networking/projects/tcptune/

"The amount of data that can be in transit in the network, termed "Bandwidth-Delay-Product," or BDP for short, is simply the product of the bottleneck link bandwidth and the Round Trip Time (RTT). BDP is a simple but important concept in a window based protocol such as TCP. Some of the issues discussed below arise because of the fact that the BDP of today's networks has increased way beyond what it was when the TCP/IP protocols were initially designed. In order to accommodate the large increases in BDP, some high performance extensions have been proposed and implemented in the TCP protocol. But these high performance options are sometimes not enabled by default and will have to be explicitly turned on by the system administrators.
Buffers

In a "reliable" protocol such as TCP, the importance of BDP described above is that this is the amount of buffering that will be required in the end hosts (sender and receiver). The largest buffer the original TCP (without the high performance options) supports is limited to 64K Bytes. If the BDP is small either because the link is slow or because the RTT is small (in a LAN, for example), the default configuration is usually adequate. But for a paths that have a large BDP, and hence require large buffers, it is necessary to have the high performance options discussed in the next section be enabled. "


There is a matematical formula for calculating RWIN

here is a calculator http://www.dslnuts.com/bitsbytes.shtml

lets try it  ;)

lets say you have a 3 Mbps Cable connection and connected directly to modem that has a 10 Mbps ethernet port

1.  in this case windows 98 as OS, DefaultReceivewindow is 8760, your cap speed is 3000/ 8,192 = 366 kB/s your MTU is 1500 and overhead 40 give you a MSS of 1460. Lets see what latency you need to get maximal speed

the calulator says 25ms

thats the worst ping you could have, meaning that it cant get over that using all your bandwidth....

as you probl know latency increase when your getting close to cap

my experiance says you need to calculate with a worst possible ping between 150-300 ms

2. in this case your using Win XP on same setup, XP using a TcpWindowsize of 17520 when your NIC is in 10 Mbps mode

so the worst possible latency cant be higher then 50ms with this OS... thats still to low to max out

3. In this case you using win XP and a router , your PC will run the NIC as fast as possible 100 Mbps to the router, that give you a TcpWindowsize of 64240, now lets calculate again, that allow a worst possible ping of 177 ms

that will work very well for download for alot of ppl

4. In this case your using XP and connect direct to modem that has a 100 Mbps port, your TcpWindowSize will be 64240 in this case you will be limited same as in case 3.


Just beqause your connection works good with default TCP values dosent mean that it will do so for all ppl....

Many times DefaultReceivewindow is too high aswell, im talking about connections below 3 Mbps

too high RWIN can slow down, if your on a route that have loss



also check this analogy 

http://www.dslreports.com/faq/7718

quote" Downloading and uploading files is like transferring a dirt pile from one location and placing it somewhere else. The dirt pile would be the (Internet Protocol)IP. The place where you are wanting to move the dirt pile would be the other IP. The process of moving the dirt over to the other location represents the TCP(Transmission Control Protocol). The wheelbarrow you will use moving the dirt represents the MTU(Maximum Transmission Unit). The amount of dirt you put into the wheelbarrow represents the RWIN(TCP Receive Window). If you put too much dirt into the wheelbarrow, it could be heavy even spilling it on the ground, that would represent the Packet Loss. If you would place less dirt in the wheelbarrow, it will be easier to haul it and you can move faster, the only catch with this is that you will have to make a few more trips in order to complete the task. As you see, you have to find that medium with the loads of dirt to the round trips to each dirt pile."

its not only RWIN thats need adjustments, over high ping routes you might need Timestamping aswell and also tweak the numbers of maximal connections for faster webrowsing

VanBuren

i dont need to dodge, you asked me where i got my information, do you want more?

I never claimed that Moderating forums speed up any connection, however i asked you where you got your information and you answered me "having built hundreds of pcs"

so whats your point?

VanBuren

2 Days ago.

Friend, on XP home.

Running fully updated Norton Antivirus 2004.

Running fully updated Adaware Professional SE w/ Subscription.

Running fully updated drivers on ALL hardware ( avaliable to him that is )

Taking speed tests to:
- various different sites.
- various different states.
- various  different  types of tests

Advertised speeds of 5000/ 768:

All tests came up as a connection not exceeding more then 25 kbs download, 45 upload.
His NIC card set from every possible duplex settings, with and w/o flow control. Results remained 25kb/45kb.

~ I simply slipped him a copy of Cablenut with my own personal settings, ( mod'ed off vanburens ) told him to hit save, and reboot.

He did. Came back,  re- tested,  getting 4.9/ 736


That right there is enough proof that cablenut helps. As for me personaly, no. Wether i have a cablenut tweak installed or not i do not see a major difference, but for alot of folks there is a noticable improvement.

'nuff said.

So we can assume that a properly set up new system with a brand new high-speed connection is automatically optimized?  How naive is that?

Is a car fresh off the factory floor better in stock form than if it was tweaked?  Will a brand new TV look better with the factory settings or after a certified technician adjusts it?  Does a video card perform best fresh out of the box with no tweaks or adjustments?

Come to think of it I cannot think of anything remotely complex that performs at its peak without any adjustments.

But really, it was very cool of you to go out of your way to come here to insult someone that devotes countless hours of his time helping people with their Internet woes. 

Wait, I thought of another example.  You came out of your mother’s womb and your stock settings resulted in you being a jerk.  Perhaps you need some adjustments.