SG Broadband Community

I'm on DSL PPPoE and understand that my MaxMTU should be set at 1492. I edited the registry to set all Nettrans settings(0000 to 0009) MaxMtu to 1492,and all other settings at suggested red settings. When I run TCP/IP analyzer my setting shows up as below..1454, yet my Registry settings are 1492. This is confusing. I also ran DRTCP and tried to set timestamps to on but it does not show up on this also. In DRTcp I have
1)Dial up Adapter
2)Network Telesystems P.P.P.o.E adapter
3)D-Link DE-528 Ethernet PCI adapter
4)D-Link DE-220 PnP Lan adapter
I choose #2 P.P.P.o.E adapter and set it at 1492 and timestamps on. I do the same for #4 which is my DSL ethernet card.I leave #1 and #3 alone. Also what should I set the tcp Receive window at in DRTCP?

Please advise if this seems correct or what I can do to get optimal settings. Thanks

TCP options string = 0204058601010402

MTU = 1454
MTU is not fully optimized for broadband. Consider increasing your MTU to 1500 for better throughput.

MSS = 1414
Maximum useful data in each packet = 1414, which is equal to MSS.
MSS is not fully optimized for broadband (although it might work well for slower connections). Consider increasing your MTU value.

Default Receive Window (RWIN) = 65535
RWIN Scaling (RFC1323) = 0 bits
Unscaled Receive Window = 65535
Note: Under Windows 9x, if you have RWIN set to any other value, and the Analyzer reports 65535 you might need to install the MS Vtcp386 fix.
For optimum performance, consider changing RWIN to a multiple of MSS.
Other values for RWIN that might work well with your current MTU/MSS:
520352 (MSS x 46 * scale factor of 8)
260176 (MSS x 46 * scale factor of 4)
130088 (MSS x 46 * scale factor of 2)
65044 (MSS x 46)

bandwidth * delay product:
Your RcvWindow limits you to: 2621.4 kbps (327.675 KBytes/s) @ 200ms
Your RcvWindow limits you to: 1048.56 kbps (131.07 KBytes/s) @ 500ms

MTU Discovery (RFC1191) = ON

Time to live left = 47 hops
TTL value is ok.

Timestamps (RFC1323) = OFF

Selective Acknowledgements (RFC2018) = ON

IP type of service field (RFC1349)= 00000000


109489 connections tested since 03.10.2001.
Analyzer version: Beta 0.94

First if you are on WIN 95/98/SE you need to go to patch page, this site, download and install Vtcp386 Fix for your OS. Then go for
help on MTU here

Thanks again Lobo. I did all you suggested and these are my results. Please let me know what you think. Should I play around with any of these settings to fine tune or leave them as they are?

TCP options string = 020405ac010303020101080a000000000000000001010402

MTU = 1492
MTU seems to be optimized for PPPoE... If you are not on a PPPoE connection, consider increasing your MTU to 1500 for optimal throughput.

MSS = 1452
Maximum useful data in each packet = 1440, which is less than MSS because of Timestamps, or other TCP/IP options used.
MSS is optimized for PPPoE. If you are not on a PPPoE connection, consider increasing your MTU value.

Default Receive Window (RWIN) = 255552
RWIN Scaling (RFC1323) = 2 bits
Unscaled Receive Window = 63888
RWIN is a multiple of MSS
Other values for RWIN that might work well with your current MTU/MSS:
511104 (MSS x 44 * scale factor of 8)
127776 (MSS x 44 * scale factor of 2)
63888 (MSS x 44)

bandwidth * delay product:
Your RcvWindow limits you to: 10222.08 kbps (1277.76 KBytes/s) @ 200ms
Your RcvWindow limits you to: 4088.832 kbps (511.104 KBytes/s) @ 500ms

MTU Discovery (RFC1191) = ON

Time to live left = 47 hops
TTL value is ok.

Timestamps (RFC1323) = ON
Note: Timestamps add 12 bytes to the TCP header of each packet, reducing the space available for useful data.

Selective Acknowledgements (RFC2018) = ON

IP type of service field (RFC1349)= 00000000

[ 04-17-2001: Message edited by: RokitSiyents ]

All looks fine but I would play until time stamps are off, try other adapters or maybe it is the correct one you selected first, but patch is in, good job