Download Speed Problem

[vatrouble]

I have been having slow download speeds for over a month.  My upload speed is fine.  I have contacted support several times.  In each case my call has been disconnected and they never call back.  The following is from result of a speed test from 12-12 using Verizon's speed test:

Web100 reports the Round trip time = 52.08 msec; the Packet size = 1452 Bytes; and
There were 73 packets retransmitted, 3 duplicate acks received, and 2 SACK blocks received
The connection stalled 3 times due to packet loss
The connection was idle 0.8 seconds (5.33%) of the time
This connection is sender limited 9.73% of the time.
This connection is network limited 90.27% of the time.

Excessive packet loss is impacting your performance.

[smith6612]

If you can, please register an account over at DSLReports.com, then visit their Tools section and choose their Ping Testing/Line Quality testing. While the Web100/NDT test is indicating a problem, whether congestion or faulty equipment, it isn't showing some other pieces of information I'm looking for as well. Mainly, I'm looking for an indication on where the problem may be, and if you are behind some notorious equipment on Verizon's end that may also be at fault. Once the line quality test completes, you will receive a message at the top of the site from "System" saying the test is complete. Open it and send me the link to the test to view it (the correct address is found inside of the test results itself, don't copy and paste it directly from the address bar!). Additionally, if you are using Wireless it's a good idea to secure it with WPA2-AES, if you haven't already just to be on the safe side. Figured I'd throw that out there as others would, plus it's good info to get around.

[vatrouble]

Thanks for the response Smith6612

Link to the test results is below:

http://www.dslreports.com/testhistory/1774641/77c2b

I am not using a wireless connection.  I made no system or equipment changes prior to the start of this problem.  I am on a Westell 2200 modem which shows the proper connection rate.

[smith6612]

There doesn't seem to be any obvious signs of congestion shown in that Line Quality test. I am missing a piece of information though which is the second last hop before it reaches your connection, and that piece of information allows me to determine what edge routing equipment you're basically being sent through. More than likely, you're on a new edge router that hasn't had a name set for it yet that I can see (Called RDNS). More than likely, it is a Juniper ERX. Can you visit http://www.speakeasy.net/speedtest and perform a test to both the New York Server, as well as the Chicago server? Give me the results you get for the download. Juniper ERX edge routers that Verizon uses tend to have an incompatibility with some of the switches they use made by Lucent, and unfortunately this causes transfer rates to run at what appears to be congestion, even though it isn't. Been a well known problem for years throughout the tech community. There are work-arounds if you run Linux, Windows XP or older and I believe OS X as it is basically Unix, though if you use Windows Vista or Windows 7, this gets difficult to solve.

[vatrouble]

Speakeasy results as follows:

     NY -  1221kbps down 685 kbps up

     Chicago - 1877kbps down 688 kbps up.

I am running Windows XP Pro SP3.

[smith6612]

OK. It looks like it's trying to hit 3Mbps, though as I predicted before we more than likely have a Juniper ERX messing things up. Go to http://www.dslreports.com/drtcp and download the .exe of Dr. TCP. Save it to your hard drive as it does not install anything to the computer. From the window, set the following options:

Set the TCP Receive Window to 13068, or to a number with a multiple of 1452 not lower than 13068.
Set Windows Scaling to Default or No
Set Time Stamping to No
Set Selective Acks to Yes
Set Path MTU Discovery to Yes
Set black Hole Detection to No
Press Save and reboot your PC. Perform a speed test to see if any speed gain has been achieved.

Realistically, based on what speed package you have, 3Mbps should max out at ~2800kbps, if you're lucky 2900Kbps. 5Mbps will max out at a little under 5000Kbps, and the 7.1Mbps package will max out at roughly 6500kbps.

[vatrouble]

You are right, I am suppose to have 3Mbps and I was getting between 2800 and 2900 Kbps all the time before.

Downloaded the program and made a couple of attempts.  One with the TCP Receive Window at 13068 and the other with TCP Receive Window at 65340.  The latter produced the best speeds but only 2036Kbps at NY and 2406Kbps at Chicago.

[smith6612]

Good. Keep playing with it until you find the optimal value for your connection. The key is to get a balance in speeds between nearby servers and far away servers, while shooting for the transfer to be as consistent and as fast as possible.

Under normal circumstances, if there wasn't this issue with the Juniper ERX routers and some Lucent Switches on Verizon's end, something that has been known for years as I mentioned earlier for trashing line quality (we've attempted to let Verizon know as well, they haven't done a whole lot about it), you should be able to get the max speeds all the time with any reasonable Receive Window value. I happen to know that my DSL line runs through the affected Lucent equipment as I am on a Litespan Remote, though fortunately for me I am still on one of the few Redback/Cisco edge routers left in operation for my area meaning I don't see this issue. I'd be stuck out in the cold if I were on a Juniper ERX as my primary PCs run Vista and Windows 7. These operating systems adjust the TCP Receive Window automatically and do not let me manually set a value. A friend of mine feeding out of the same remote down the street from me has 3Mbps DSL (used to have 768k) and he happened to land on a Juniper ERX. Of course, regardless of his speed package, his throughput is basically completely trashed despite there being no congestion. I'm going to be getting someone with the power to change things around a bit to fix his line up so he can actually download things without having it run at 40KB/s-160KB/s most of the time. It's rare to see times where his line can pull over 190KB/s, mostly FTP transfers which are far and few. Most downloads on his line are via Xbox Live, Steam and HTTP. It's sad when my 1Mbps line is smoking his 3Mbps line in speed, yet his line has a stronger signal coming in. He knows what the problem is thanks to what I've told him, and there are a ton of others in my area affected by the same problem and don't even know it.