WAY O/T & Nerdy - TCP Settings

[Captain Colonial]

OK, computer nerds, help a leper.

I've got Virgin 20Mb cable broadband connection through an Ambit USB Cable |Modem (via an ethernet connection and a Belkin wired router), but the download and upload speeds I get are nowhere near what they should be.  In my ignorance, I put this down to the settings not being changed after I upgraded to a higher speed.  The computer is a 2.6 P4 with 2Mb of memory.

I've tried measuring it on Speedtest.net, and download is some place between 1Mb and 2.5Mb at best. Pathetic.

This is after I used Dr TCP and also SG TCP Optimizer too.  Changing and playing with the TCP Receive Window has helped a bit, but things should be much better than this.  Bear in mind that changing these settings is a black art to me, and I don't know where the starting point is, i.e. is 20Mb the rate per second, minute (can't find anything one way or the other), and how does this affect RWIM?

So I need to know what setting to change if any, or if there is a problem area I should be looking at.  Currently:

> TCP Receive Window is at 1250000

> MTU 1500

> Latency RTT 130ms average

Or is the hardware the problem?

Any ideas gratefully received.

Now my brain hurts.  And I'll bet Blatters tells me to do a search.

TIA!          

[CedricTheBrave]

what speed is the belkin rated at?

also remember that you will probably be in a 50-1 contention ratio area which means that up to 50 users can be sharing your 20mb at any one time

unless Virgin state a different ratio for cable users

[Captain Colonial]

It doesn't say what speed it's rated at. b*******.

And I didn't know about the 50-1 thing! Feck.

[Blatman]

Where are you in the UK? Virgin are currently rolling out the 20Mb service, so you may not have been upgraded yet, akthough I assume that if they've sold it to you it should be available...

Anyhow the scedule for upgrades is here.

As for the 50-1 thing, that's the contention ratio. *All* internet services are contended, which means more than one person using it at a time. The more people on line at once, the slower it will be. So, if you have a couple of gamers or serious P2P sharers on line, speeds may drop dramatically even though the actual number of users sharing the connection may be low. Can't seem to see contention ratio mentioned anywhere on the Virgin site though, although I didn't have a *good* look...

And you should have more than 2Mb of memory (I assume RAM). I would hope you mean 2Gb of memory. 2Mb of memory isn't enough to open a nice photo quickly...

[Captain Colonial]

Yes, sorry, it's 2Gb, not Mb.  Blast.

My area has been upgraded to 20Mb.  Is that supposed to be per second? And what's the difference between kilobytes, kilobits, and megabits?

[Blatman]

Broadband speed is usually measured in megabits per second.

1 byte is the smallest data unit.

8 bytes = 1 bit

1012 bits = 1 kilobyte

128 kilobytes = 1 megabit

8 megabits = 1 megabyte. File sizes are usually measured in Megabytes or megs.

128 megabytes = 1 gigabit

8 gigabits = 1 gigabyte Hard drives are measured in Gigabytes (Gig or Gigs)

1024 Gigs = 1 Terabyte

128 terabytes = 1 petabit

1024 terabytes = 1 petabyte

[Guest]

Yes, sorry, it's 2Gb, not Mb.  Blast.

My area has been upgraded to 20Mb.  Is that supposed to be per second? And what's the difference between kilobytes, kilobits, and megabits?

a bit is a single 1 or 0

a byte is an 8 bit word (8 bits in a line eg 10101010)

Kilo is a scientific notation meaning x1000 eg kilo gram = 1000gram, kilo bit = 1000 bits and kilo byte = 1000 bytes

Mb is mega bits (mega being x 1000000) not to be confused with MB which is mega bytes (1000000 bytes)

Mb/second is what you line speed is given in (mega bits per second) which is a lot different to MB/second which is what the data transfer rate of your hard disk is measured in!

Now the bit i can't tell you is why connections are advertised in Mb/s (megabits/second) then download speeds given in KB (kilobytes/second)

But as an example:

A 2Mb connection (std broadband) you will achieve a maximum of 250KB/second

2000000 Bits/second = 250000bytes per second.....  2000000/8 = 250000

God i feel like a geek now!  

GB is gigabyte

[Guest]

Broadband speed is usually measured in megabits per second.

1 byte is the smallest data unit.

8 bytes = 1 bit

1012 bits = 1 kilobyte

128 kilobytes = 1 megabit

8 megabits = 1 megabyte. File sizes are usually measured in Megabytes or megs.

128 megabytes = 1 gigabit

8 gigabits = 1 gigabyte Hard drives are measured in Gigabytes (Gig or Gigs)

1024 Gigs = 1 Terabyte

128 terabytes = 1 petabit

1024 terabytes = 1 petabyte

Sorry blatters... not even close to the mark  

[Blatman]

Sorry blatters... not even close to the mark  

You're right. Badly calculated indeed and far from my best work

There's a calculator here. Much easier than typing it all from memory (sorry...).

Are your numbers the IEC standard? I actually prefer the old standard that uses the non rounded numbers calculated from the original binary, IIRC...

[Guest]

Sorry blatters... not even close to the mark  

Wanna bet? I may have made a couple of errors where I have 8's instead of 4's on some of the bigger numbers (I think I should have more 1024's or 124's in there), but there definitely *aren't* any "round" numbers in computer memory round ups...

Better yet. There's a calculator here...

Try it on your calculator...

convert 2000000 bits into KiloBytes (2Mb = 244 KB)

convert 8 bits into bytes (8bits = 1 byte)

I simplified the numbers a little by leaving things in base 10 instead of base 2, hence the round number point you make is correct.

to be perfectly accurate 1024 bits = 1 kilo bit

and 1024 bytes = 1 kilo byte

1024000 bits = 1 Mb

1024 KB = 1MB

I concede that you have the right relationships in places, I think your fundamental error in the first line is what made it appear totally flawed!!

a bit is a single digit and a byte is an 8 bit word... maybe the late hour left you tongue tied as you seem to have got the 8 bit to 1 byte relationship later on!

[Blatman]

concede that you have the right relationships in places, I think your fundamental error in the first line is what made it appear totally flawed!!

a bit is a single digit and a byte is an 8 bit word... maybe the late hour left you tongue tied as you seem to have got the 8 bit to 1 byte relationship later on!

It was a bit late, and I was deep in to a bottle of Merlot, which was nice last night, but no so much fun this morning

I also edited my post a couple of times once the two ior three neurons that were firing remembered how to count in binary...

Next job, find some coffee...

[Mike H]

Forget the SI stuff, K and M belong in the computer world and base 2.

In the 8 bit byte computer world:

MB = megabyte

Mb = megabit

KB = kilobyte

Kb = kilobit

1MB is 8Mb is 1024KB or 8192 Kb or 8388608 bits

2^3 bits = 1 byte

2^10 bits = 1 kilobit

2^13 bits = 1 kilobyte = 2^3 kilobits = 2^10 bytes

2^20 bits = 1 megabit

2^23 bits = 1 megabyte = 2^3 megabits = 2^10 kilobytes

2^30 bits = 1 gigabit

2^33 bits = 1 gigabyte = 2^3 gigabits = 2^10 megabytes

etc

etc

[DavidR]

Back to the topic . . . .

I use this to tweak network settings .  .Cybertweak network optimiser and if a speed test stil comes up with lower than expected speeds then , i'm afraid, it's on to the the delights of Virgin call centre to complain.

quote from my email from Virgin

"From 1st July, our broadband helpline number is changing and from then on it'll cost 25p per minute to call from a Virgin home phone, plus 10p to connect. The new number is 0906 212 1111.

So when you need help, here's what to do:

Step 1

If you're having trouble with your broadband service, for example if it's running slower than it should be, the first thing to do is switch off your computer and modem, then restart it again. This may repair any basic faults right away and get you back up and running quickly.

Step 2

If that didn't work, the next thing to do is call our service status line on 0800 561 0061 to find out if there's a problem in your area. It's absolutely free. Or if you still have access to the internet, you can visit our help site. It's at http://www.virginmedia.com/help"

Good luck

David