I have the following problem which drives me crazy...I have a 100 Mbit/s cable internet access which until two weeks ago allowed me to download from my News Server (Newshosting) with 100 Mbit/s. This worked for over a year. Suddenly, I am getting no more than 60 Mbit/s. Im am not aware of any changes that might have caused this. So I twice checked with my ISP and they say everything is OK. They gave me a TCP optimizer utility which I applied, but no change.
There is no LAN involved (Ethernet cable between cable modem and Win7-PC) and also no change even with disabled firewall and anti virus program. Then I checked with newshosting and they say that they do not throttle anything (which I believe because I had full bandwidth for over one year) and my trace route would be OK...so also no problem on their end. But to be sure, I tested another news server (maximumusenet) with exactly the same result (60 Mbit/s). I tried all the port settings they mention with or without SSL but no change.
I now do not know what else I could try and I am grateful for every hint you can give me - thanks, Stefan
The SG traceroute brings:
traceroute to news.newshosting.com (126.96.36.199), 30 hops max, 60 byte packets
1 68-67-73-17.static.gorack.net (188.8.131.52) 0.384 ms 0.383 ms 0.588 ms
2 66-193-173-205.static.twtelecom.net (184.108.40.206) 0.371 ms 0.603 ms 0.604 ms
3 mia2-pr1-xe-0-3-0-0.us.twtelecom.net (220.127.116.11) 13.351 ms 13.359 ms 13.355 ms
4 1-2.r1.at.hwng.net (18.104.22.168) 26.641 ms 31.833 ms 32.085 ms
5 2-1.r2.dc.hwng.net (22.214.171.124) 42.364 ms 40.880 ms 42.583 ms
6 ve1006.ar2.dc.hwng.net (126.96.36.199) 34.750 ms ve924.ar4.dc.hwng.net (188.8.131.52) 33.919 ms
ve923.ar3.dc.hwng.net (184.108.40.206) 33.890 ms
7 news.iad.newshosting.com (220.127.116.11) 34.442 ms 34.613 ms 18.104.22.168 (22.214.171.124) 34.739 ms
SG TCP Analyzer brings:
TCP options string = 020405b40103030201010402
MTU = 1500
MTU is fully optimized for broadband.
MSS = 1460
Maximum useful data in each packet = 1460, which equals MSS.
Default TCP Receive Window (RWIN) = 65700
RWIN Scaling (RFC1323) = 2 bits (scale factor: 2^2=4)
Unscaled TCP Receive Window = 16425
In Windows 7, unless "TCP/IP Auto-Tuning" is disabled, only the Current TCP Window is displayed. Use the SG Vista TCP/IP
patch instead of the TCP Optimizer for automatic tweaking.
RWIN is not fully optimized (even though it is a comparatively large number). The unscaled RWIN value is lower than it
should be. Also, RWIN being close to and above 65535 does not justify the header overhead of enabling TCP 1323 Options.
You might want to use one of the recommended RWIN values below.
RWIN is a multiple of MSS
Other RWIN values that might work well with your current MTU/MSS:
64240 (up to 2 Mbit lines, depending on latency. MSS * 44)
128480 (1-5 Mbit lines, depending on latency. MSS * 44 * 2)
256960 (2-14 Mbit lines, depending on latency. MSS * 44 * 2^2)
513920 (8-30 Mbit lines, depending on latency. MSS * 44 * 2^3)
1027840 (25-60 Mbit lines depending on latency. MSS * 44 * 2^4)
bandwidth * delay product (Note this is not a speed test):
Your TCP Window limits you to: 2628 kbps (329 KBytes/s) @ 200ms
Your TCP Window limits you to: 1051 kbps (131 KBytes/s) @ 500ms
MTU Discovery (RFC1191) = ON
Time to live left = 49 hops
TTL value is ok.
Timestamps (RFC1323) = OFF
Selective Acknowledgements (RFC2018) = ON
IP type of service field (RFC1349) = 00000000 (0)