SuperCharged EVDO - Free Performance Tip

Bigdave · EVDO Addict Joined: 08 Nov 2006 Posts: 1068

It actually sounds like you're on Rev 0 and thus are getting pretty average speeds. Are you sure you're on Rev A? Have you checked via SCM? Hover your mouse over the signal meter in the Sprint Connection Manager (SCM) and see what pops up. The signal with the * beside it is the one your connected to. Lower numbers are better. Also, it'll show 1X, 1XEVDO, or EVDO Rev A.

Victorthebattousai · EVDO Newbie Joined: 03 May 2007 Posts: 3

1xEVDO Rev A -81 dbm. I have called Sprint Customer Support, all they can tell me is "I don't know." The only one that acted like he knew what was up was the manager or something, and he said that these speeds were normal. If theey're normal, why is sprint advertising higher? A LOT higher, in the Upload's case.

gil · EVDO User Joined: 31 Dec 2006 Posts: 82

This is a cable connection on a desktop I bought in 2001, my new laptop is more responsive with a EVDO connection because of the obvious improvements in memory and graphics. I could upgrade this computer but my ex- Confused

wife likes it like it is.
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longtimelurker

magicjimmy · Posted: Sat May 05, 2007 5:17 pm Post subject:

Victorthebattousai · EVDO Newbie Joined: 03 May 2007 Posts: 3

I'd rather try some of these booster-type things first.

A couple days ago, We lost the laptop, bought a PCI/PCMCIA card for our desktop, and it's getting a slower DL (about 470-500 kbps), but a MUCH faster UL(somewhere around 300-350 kbps). Which of these programs should I try?

toad · EVDO Fledgling Joined: 06 Jul 2006 Posts: 23

Any way to put this tip to use with a KR1?

justanoldguy · EVDO Fledgling Joined: 05 Mar 2007 Posts: 14

I found that tweaking each computer in a manner that allows you to get the best throughput (transfer efficiency) with the fewest retransmitted packets to work best. All computers run through my KR1.

From dslreports:

1. Your Tweakable Settings:
Receive Window (RWIN): 37960
Window Scaling: off
Path MTU Discovery: ON
RFC1323 Window Scaling: OFF
RFC1323 Time Stamping: OFF
Selective Acks: ON
MSS requested: 1460
TTL: unknown
TTL remaining: 50

2. Test Download
Actual data bytes sent: 1024001
Actual data packets: 703
Max packet sent (MTU): 1500
Max packet recd (MTU): 1500
Retransmitted packets: 0
sacks you sent: 0
pushed data pkts: 106
data transmit time: 7.139 secs
our max idletime: 549.7 ms
transfer rate: 130478 bytes/sec
transfer rate: 1043 kbits/sec
transfer efficiency: 100%

Notes and recommendations:
RWIN is in range
Looking good

Observations:
Good data stream (no/few rexmits)

From speedguide:

« SpeedGuide.net TCP Analyzer Results »
Tested on: 05.14.2007 06:58
IP address: 68.246.xxx.x

TCP options string: 020405b401010402
MSS: 1460
MTU: 1500
TCP Window: 37960 (multiple of MSS)
RWIN Scaling: 0
Unscaled RWIN : 37960
Reccomended RWINs: 64240, 128480, 256960, 513920
BDP limit (200ms): 1518kbps (190KBytes/s)
BDP limit (500ms): 607kbps (76KBytes/s)
MTU Discovery: ON
TTL: 43
Timestamps: OFF
SACKs: ON
IP ToS: 10111000 (184)
Precedence: 101 (CRITIC/ECP)
Delay: 1 (low delay)
Throughput: 1 (low throughput)
Reliability: 0 (normal reliability)
Cost: 0 (normal cost)
Check bit: 0 (correct)
DiffServ: EF PHB 101110 (46) - Expedited Forwarding (recommended for video/audio - high priority, higher drop probability). See RFC 2598.

:::.. Download Stats ..:::
Download Connection is:: 1371 Kbps about 1.4 Mbps (tested with 1496 kB)
Download Speed is:: 167 kB/s
Tested From:: http://testmy.net/ (Server 1)
Test Time:: 2007/05/14 - 3:49am
Bottom Line:: 24X faster than 56K 1MB Download in 6.13 sec
Tested from a 1496 kB file and took 8.938 seconds to complete
Download Diagnosis:: Looks Great : 10.92 % faster than the average for host (spcsdns.net)
D-Validation Link:: http://testmy.net/stats/id-6P74HR8LM
User Agent:: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.3) Gecko/20070309 Firefox/2.0.0.3 [!]

:::.. Upload Stats ..:::
Upload Connection is:: 443 Kbps about 0.4 Mbps (tested with 1496 kB)
Upload Speed is:: 54 kB/s
Tested From:: http://testmy.net/ (Server 1)
Test Time:: 2007/05/14 - 3:50am
Bottom Line:: 8X faster than 56K 1MB Upload in 18.96 sec
Tested from a 1496 kB file and took 27.687 seconds to complete
Upload Diagnosis:: Awesome! 20% + : 151.7 % faster than the average for host (spcsdns.net)
U-Validation Link:: http://testmy.net/stats/id-Y09EOZL6B
User Agent:: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.3) Gecko/20070309 Firefox/2.0.0.3 [!]

All my machines get the same results. I use a combo of DRTCP and Cablenut (from my satellite days Rolling Eyes

).
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S720/KR1 Rev A

mattengland · Posted: Tue Jun 26, 2007 5:28 pm Post subject:

Could someone possibly summarize the validated suggestions in this thread?

So far I see:

* Change the TCP receive window size to 65536 (using DrTCP)
* Run Cablenut software

Any others? I'm trying to make an evdo-performance-enhancment guide:

http://www.evdoforums.com/thread6137.html

...and am looking to make "tips" more accessible (eg, so that one--including myself--doesn't have to read through a 9-page thread like this one to get the pertinent info).

Also, how can one tell their current service's signal strength? I see some posters saying something like "I have a -85db signal," but I don't know how to acquire that info.

Thanks for any help.

mattengland · Posted: Tue Jun 26, 2007 5:30 pm Post subject:

Additionally: Is there a tradeoff involved with changing the TCP receive window size? I suspect this may help increase bandwidth in many cases, but might reduce latency in some (but I'm not a networking expert, just taking an educated guess).

Forgive me if this was already asked and answered...but this thread is 9 pages long and I'm not quite up for reading every post at the moment.

Alex · Site Admin Joined: 19 Sep 2006 Posts: 1943

mattengland · Posted: Tue Jun 26, 2007 5:40 pm Post subject:

mattengland · Posted: Tue Jun 26, 2007 5:47 pm Post subject:

justanoldguy · EVDO Fledgling Joined: 05 Mar 2007 Posts: 14

From SpeedGuide.net

RWIN (TCP Receive Window) is a buffer that determines how much data the receiving computer is prepared to get at one time.

A RWIN value that's too large will result in greater loss of data if a packet is lost or damaged. A too small RWIN will be very slow, as each packet will have to be acknowledged before the next packet is sent.

RWIN is one of the most important parameters in tweaking any TCP/IP connection.

First, your RWIN should be a multiple of your MSS. Your MSS is MTU - 40. My MTU is 1500, therefore my MSS is 1460. Everyone using EVDO should have an MTU of 1500.

I use 37960 which is a multiple of MSS (1460 x 26 = 37960).
When I increased this number I found that I was getting retransmitted packets which were affecting my data stream. When using 37960, I get a transfer efficiency of 100% and great speeds. You can test your system at dslreports.com (under tools, then tweak test).

Hope this helps a little. It certainly helped my EVDO connection whether I'm using Sprint or Verizon.
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S720/KR1 Rev A

mattengland · Posted: Tue Jun 26, 2007 7:19 pm Post subject:

Great info, justanoldguy. Some followup questions:

justanoldguy · EVDO Fledgling Joined: 05 Mar 2007 Posts: 14

mattengland,

Go to www.speedguide.net. On the left column put your cursor over Broadband, then click on Broadband Tools, then SG TCP/IP Analyzer .

RWIN (TCP Receive Window) is the amount of data that your computer can accept without acknowledging the sender.

MTU - (Maximum Transmission Unit) Is the greatest amount of data that can be transferred in one physical frame on the network. If a packet that has a smaller MTU than the packet's frame length is sent, fragmentation will occur.

MSS - (Maximum Segment Size) Defines the largest segment of TCP data that the Winsock is prepared to receive. When a connection is established, the two ends agree to use the smaller of each end's value. Because headers are typically 40 bytes, set the MSS to 40 less than the MTU.

For info on how to use Cablenut go here: http://dslnuts.com/tips_tricks.shtml
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S720/KR1 Rev A