SG Broadband Community

Posted: **Thu Jul 31, 2003 7:26 am**

TCP options string = 020405b40103030101010402
MTU = 1500
MTU is fully optimized for broadband.
MSS = 1460
Maximum useful data in each packet = 1460, which equals MSS.

Default Receive Window (RWIN) = 81760
RWIN Scaling (RFC1323) = 1 bits
Unscaled Receive Window = 40880

RWIN is a multiple of MSS
Other values for RWIN that might work well with your current MTU/MSS:
513920 (MSS x 44 * scale factor of 8)
256960 (MSS x 44 * scale factor of 4)
128480 (MSS x 44 * scale factor of 2)
64240 (MSS x 44)
bandwidth * delay product:

Your RcvWindow limits you to: 3270.4 kbps (408.8 KBytes/s) @ 200ms
Your RcvWindow limits you to: 1308.16 kbps (163.52 KBytes/s) @ 500ms
MTU Discovery (RFC1191) = ON
Time to live left = 51 hops

TTL value is ok.
Timestamps (RFC1323) = OFF
Selective Acknowledgements (RFC2018) = ON
IP type of service field (RFC1349) = 00000000

what i would like to know is the unscaled receive win right.
when i try to go to the rwin scaling to unchack it. it set my unscaled num to sumething diff

Posted: **Thu Jul 31, 2003 8:10 am**

Welcome to Speedguide

, please read here so that we can properly help you, please read it carefully since it will most likely answer any questions you may have. If after reading it you still need help please post the answers to the questions at the top.

Posted: **Fri Aug 01, 2003 8:24 am**

comcast 1800-256
win 2000

what i was aking was not in your help list

RWIN Scaling (RFC1323) = 1 bits
how do i go to rfc =0 bits and still keep my RWIN Scaling RWIN) = 81760 as soon as i set this numbers in the optimizer the rfc 1 bits well come on.

ok let me see if i have this right. the 81760 is to big of a number for the rfc it have to be set at 1 bit is that right

Posted: **Fri Aug 01, 2003 8:41 am**

Tcp1323Opts - This parameter controls RFC 1323 time stamps and window-scaling options. Time stamps and window scaling are enabled by default, but can be manipulated with flag bits. Bit 0 controls window scaling, and bit 1 controls time stamps.

Value Type: REG_DWORD—number (flags)

Valid Range: 0, 1, 2, 3

0 (disable RFC 1323 options)
1 (window scale enabled only)
2 (timestamps enabled only)
3 (both options enabled)

This enables Windows Scaling which allows for RWINs larger than 65535. With your caps there is no need to use a value this large.

Posted: **Sat Aug 02, 2003 7:08 am**

hay ty for the reply that helps a lot ummm time for more testing then.

Posted: **Sun Aug 03, 2003 6:43 am**

sorry to ask this but . i dont think there is a tweak for it uplode?? or is that the isp or the pc?? my uplode is 190

Posted: **Sun Aug 03, 2003 9:31 am**

The only setting that is directly related to upload is DefaultSendWindow, it is an AFD parameter that uses RAM as a buffer. Also if your RWIN is too high then it will also slow your download.

In my opinion you should lower your RWIN to 64240 or lower, I suggest trying 37960.

Posted: **Mon Aug 04, 2003 4:18 am**

ty ill try the 37960 right now im at 64240. in testing latency the highest was at 297m and in the cablenut the guild said to set at 67160 .ty for the reply