Downloads stall....

bobolito · Post by **bobolito** » Wed Aug 01, 2007 11:49 pm

I have a desktop computer running XP w/SP2 all updated. I use a D-Link WDA-2320 PCI wireless card to connect to my router.

I have a problem where SOME downloads stall. For instance, I cannot watch movie trailers from Netflix, or from Apple. However, I can watch them just fine from Apple if they use the external player only. So, those trailers that use the browser plug-in (Flash or Quicktime) download partially and stall. On the other hand, I can watch streaming HD video from http://www.abc.com or Yahoo movies just fine. With Youtube it is strange because I can only watch full Youtube videos when Youtube is slow (around 1 or 2mbps). However, when Youtube videos download fast (6+mbps) then they always stall in the first few seconds. So that makes it impossible to watch YouTube late at night when the Internet is fast.

One major difference with both the abc.com and Yahoo movie players (both of which are Flash) is that rather than downloading continuously, they stream the video in quick bursts. So I see my bandwidth meter jump from 0 to 10mbps constantly every couple of seconds when I am watching one of those videos. With Netflix, YouTube, etc. the video is supposed to be downloaded continuously until the end while the player is catching up behind. This seems to be why the abc.com and Yahoo.com players do not stall.

It seems that fast continuous downloads will stall, but bursty and slow ones will not stall.

The same happens when I perform a speed test from Speakeasy.net/speedtest or speedtest.net. If I use a fast server, like NYC, my download speed will be very fast (10+mbps) but will only last less than a second because it stalls. However, if I pick a server that is slow, it will complete the test.

Anyone has any explanation for this?

trogers · Post by **trogers** » Wed Aug 01, 2007 11:53 pm

What speed did you pay your ISP to give you?

Post your TCP Analyzer report.

bobolito · Post by **bobolito** » Wed Aug 01, 2007 11:55 pm

I have a 15mbps down, 2mbps up connection. I forgot to mention that I use Eeye Blink Personal Security software (which does Firewall/Antivirus/Antispyware, etc.) and I am suspecting this is the source of the problem.

Here are the TCP Analyzer results:

« SpeedGuide.net TCP Analyzer Results »
Tested on: 08.02.2007 00:19
IP address: 69.115.xxx.xx

TCP options string: 020404ec0103030401010402
MSS: 1260
MTU: 1300
TCP Window: 1028160 (multiple of MSS)
RWIN Scaling: 4
Unscaled RWIN : 64260
Reccomended RWINs: 65520, 131040, 262080, 524160
BDP limit (200ms): 41126kbps (5141KBytes/s)
BDP limit (500ms): 16451kbps (2056KBytes/s)
MTU Discovery: ON
TTL: 49
Timestamps: OFF
SACKs: ON
IP ToS: 00000000 (0)

trogers · Post by **trogers** » Thu Aug 02, 2007 2:11 am

MTU is too low and TCP Window is too high. What kind of internet service do you have? Cable, PPPoA or PPPoE?

Try the following with TCP Optimizer:

General Settings tab:
Custom settings - check
Modify All Network Adapters - check
network adapter selection - your NIC
MTU 1500
TTL - 64
TCP Receive Window - 256960
MTU Discovery - Yes
Black Hole Detect - No
Selective Acks - Yes
Max Duplicate ACKs - 2
TCP 1323 Options:
Windows Scaling - checked
Timestamps - uncheck

Advanced Settings tab:
Max Connections per Server - 10
Max Connections per 1.0 Server - 20
LocalPriority - 1
Host Priority - 1
DNSPriority - 1
NetbtPriority - 1
Lan Browsing speedup - optimized
QoS: NonBestEffortLimit - 0
ToS: DisableUserTOSSetting - 0
ToS: DefaultTOSValue - 80
MaxNegativeCacheTtl - 0
NetFailureCacheTime - 0
NegativeSOACache Time - 0
LAN Request Buffer Size - 32768
Then select "Apply Changes" and reboot to take effect

After reboot, post a new TCP Analyzer report.

bobolito · Post by **bobolito** » Thu Aug 02, 2007 9:39 pm

Yeah, I thought the TCP Window was too high, but that's what TCP Optimizer suggested as the optimal setting. As for the MTU, TCP Optimizer suggested 1500 and that seemed to lessen the problem, however it is still there. Now, downloads take a few seconds longer to stall, but they still stall depending on how fast they go. The faster they go, the quicker they stall.

I have Optimum Online cable service, 15mbps down, 2mbps up. The router I have is a D-Link DIR-625 and my PCI wireless card is a D-Link WDA-2320.

Thanks for your suggestions. I tried them but it seemed to make no difference. The speed tests are stalling, and the Netflix movie trailers are not downloading fully. So the problem is the same.

Here's what TCP Analyzer said:

« SpeedGuide.net TCP Analyzer Results »
Tested on: 08.02.2007 21:56
IP address: 69.115.xxx.xx

TCP options string: 020405b40103030201010402
MSS: 1460
MTU: 1500
TCP Window: 256960 (multiple of MSS)
RWIN Scaling: 2
Unscaled RWIN : 64240
Reccomended RWINs: 64240, 128480, 256960, 513920
BDP limit (200ms): 10278kbps (1285KBytes/s)
BDP limit (500ms): 4111kbps (514KBytes/s)
MTU Discovery: ON
TTL: 49
Timestamps: OFF
SACKs: ON
IP ToS: 00000000 (0)

The strange thing is, I have my laptop right next to me and I try the same things and they all work fine. This is only happening in my desktop computer.

trogers · Post by **trogers** » Thu Aug 02, 2007 11:33 pm

Do a tracerrt to http://www.yahoo.com with your desktop and post.

Also, do this NDT test and post the report under the 'Statistics' button:

http://nitro.ucsc.edu/

bobolito · Post by **bobolito** » Fri Aug 03, 2007 1:41 am

Here's TRACERT from my Command Prompt window.

Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.

C:\Documents and Settings\bobolito>tracert http://www.yahoo.com

Tracing route to http://www.yahoo-ht3.akadns.net [87.248.113.14]
over a maximum of 30 hops:

1 1 ms <1 ms <1 ms 192.168.1.1
2 5 ms 7 ms 7 ms 10.69.32.1
3 6 ms 6 ms 7 ms dstswr1-vlan2.rh.ptsnnj.cv.net [67.83.253.161]
4 * * * Request timed out.
5 * * * Request timed out.
6 9 ms 9 ms 8 ms 64.15.0.65
7 30 ms 31 ms 31 ms 64.15.0.98
8 * * * Request timed out.
9 30 ms 31 ms 29 ms nyk-bb2-pos7-1-0.telia.net [213.248.80.74]
10 100 ms 99 ms 99 ms ldn-bb1-link.telia.net [80.91.249.248]
11 111 ms 110 ms 114 ms dln-b1-link.telia.net [80.91.250.85]
12 115 ms 115 ms 113 ms yahoo-115023-dln-b1.c.telia.net [213.155.141.182
]
13 116 ms 114 ms 118 ms ge-1-3.bas-b2.ird.yahoo.com [87.248.101.7]
14 113 ms 114 ms 114 ms f1.us.http://www.vip.ird.yahoo.com [87.248.113.14]

Trace complete.

bobolito · Post by **bobolito** » Fri Aug 03, 2007 1:45 am

Here's the UC Santa Cruz NDT test:

WEB100 Enabled Statistics:
Checking for Middleboxes . . . . . . . . . . . . . . . . . . Done
checking for firewalls . . . . . . . . . . . . . . . . . . . Done
running 10s outbound test (client-to-server [C2S]) . . . . . 1.00Mb/s
running 10s inbound test (server-to-client [S2C]) . . . . . . 9.21Mb/s

------ Client System Details ------
OS data: Name = Windows XP, Architecture = x86, Version = 5.1
Java data: Vendor = Sun Microsystems Inc., Version = 1.6.0_01

------ Web100 Detailed Analysis ------
10 Mbps Ethernet link found.
Link set to Full Duplex mode
No network congestion discovered.
Good network cable(s) found
Normal duplex operation found.

Web100 reports the Round trip time = 99.31 msec; the Packet size = 1460 Bytes; and
There were 10 packets retransmitted, 321 duplicate acks received, and 168 SACK blocks received
The connection was idle 0 seconds (0%) of the time
C2S throughput test: Packet queuing detected: 0.92%
S2C throughput test: Packet queuing detected: 0.36%
This connection is receiver limited 2.62% of the time.
This connection is network limited 97.21% of the time.

Web100 reports TCP negotiated the optional Performance Settings to:
RFC 2018 Selective Acknowledgment: ON
RFC 896 Nagle Algorithm: ON
RFC 3168 Explicit Congestion Notification: OFF
RFC 1323 Time Stamping: OFF
RFC 1323 Window Scaling: ON

Server 'nitro.ucsc.edu' is not behind a firewall. [Connection to the ephemeral port was successful]
Client is probably behind a firewall. [Connection to the ephemeral port failed]
Packet size is preserved End-to-End
Server IP addresses are preserved End-to-End
Information: Network Address Translation (NAT) box is modifying the Client's IP address
Server says [69.115.214.94] but Client says [192.168.1.12]

mccoffee · Post by **mccoffee** » Fri Aug 03, 2007 1:59 am

login into your router click on advaced tab on the top then click advanced network make sure you are allowing wan pint to get though. in this enable wan ping responding check that box. Also not sure if you had tweak ur connection before if you did leave the TOS ,or type of service feild balnk..ToS:

DefaultTOSValue - change this blank save changes reboot.

If you haven't already update the fimware on the router use manual ip's on the computer.

Thease tips should help the stalling..

bobolito · Post by **bobolito** » Fri Aug 03, 2007 11:18 am

mccoffee, thanks for the suggestions. I only understood what you wrote about allowing ping from the WAN side. I did this but it did not help, so I disabled it again for security reasons.

However, I think I found what the problem is but I am not 100% sure yet. My Blink security software has a Intrusion Prevention feature which I've just disabled and now it seems that downloads are fine. I guess the Intrusion Prevention feature thinks that the fast data stream is a DoS attack or something. I have to find out what rules I need to modify so that it doesn't block my downloads.

I've run a few speed tests and they are not getting cut off now. Netflix videos seem to be working fine as well. I have to wait until tonight when the internet gets at its maximum speed to be sure it's not going to stall. However, I did several speed tests a few mins ago that peaked at about 12mbps (but averaged around 9mbps) and they didn't get cut off. Usually late at night I can get the average speed to reach 13mbps.

The strange thing is that I have the same configuration with Blink in my laptop and downloading fast has never been a problem. Intrusion Prevention has its default settings as I have never touched those settings since Blink was installed.