SG Broadband Community

WEB100 Enabled Statistics:
Checking for Middleboxes . . . . . . . . . . . . . . . . . . Done
running 10s outbound test (client to server) . . . . . 291.27Kb/s
running 10s inbound test (server to client) . . . . . . 2.72Mb/s

------ Client System Details ------
OS data: Name = Windows 2000, Architecture = x86, Version = 5.0
Java data: Vendor = Sun Microsystems Inc., Version = 1.4.2_04

------ Web100 Detailed Analysis ------
Cable modem/DSL/T1 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 = 149.86 msec; the Packet size = 1380 Bytes; and
There were 5 packets retransmitted, 42 duplicate acks received, and 46 SACK blocks received
The connection was idle 0 seconds (0%) of the time
This connection is receiver limited 52.43% of the time.
Increasing the current receive buffer (63.0 KB) will improve performance
This connection is network limited 47.51% of the time.
Contact your local network administrator to report a network problem

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: OFF
Information: Network Middlebox is modifying MSS variable
Server IP addresses are preserved End-to-End
Client IP addresses are preserved End-to-End



TCP properties for IP =
Browser/OS = Mozilla/5.0 (Windows; U; Windows NT 5.0; rv:1.7.3) Gecko/20041001 Firefox/0.10.1
Notes: Read the Analyzer FAQ if the above is not your IP address.
TCP options string = 020405b401010402
MTU = 1500
MTU is fully optimized for broadband.
MSS = 1460
Maximum useful data in each packet = 1460, which equals MSS.
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:
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 (Note this is not a speed test):

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 = 53 hops

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

The statistic Im concerned about is from WEB100 -
Increasing the current receive buffer (63.0 KB) will improve performance

Do I need to change anything ?

Here are my CableNut settings:

DefaultReceiveWindow 393216
DefaultSendWindow 65536
DisableAddressSharing 1
InitialLargeBufferCount 200
InitialMediumBufferCount 480
InitialSmallBufferCount 640
LargeBufferSize 819200
MaxFastTransmit 64000
MediumBufferSize 150400
PriorityBoost 0
SmallBufferSize 12800
TransmitWorker 32
FastSendDatagramThreshold 4096
EnableFastRouteLookup 1
EnablePMTUDiscovery 1
IgnorePushBitOnReceives 0
GlobalMaxTcpWindowSize 65535
MaxFreeTcbs 8000
MaxHashTableSize 16384
MaxNormLookupMemory 5000000
SackOps 1
SynAttackProtect 1
Tcp13230pts 0
TcpLogLevel 1
TcpMaxDupAcks 2
TcpMaxHalfOpen 100
TcpMaxHalfOpenRetired 80
TcpRecevSegmentSize 1460
TcpSendSegmentSize 1460
TcpTimedWaitDelay 30
TcpUseRFC1122UrgentPointer 0
TcpWindowSize 65535
MaxConnectionsPer1_0Server 40
MaxConnectionsPerServer 20
DefaultTTL 128
DisableUserTOSSetting 0
TcpMaxDataRetransmissions 6
DefaultTOSValue 240

You need to change the following:

DefaultReceiveWindow - 384000
DefaultSendWindow - 32768
GlobalMaxTcpWindowSize - 64240
TcpWindowSize - 64240

Where is that an increase in my current receive buffer by 63kb that WEB100 says will increase my performance ?

DefaultReceiveWindow 384000
DefaultSendWindow 32768
DisableAddressSharing 1
InitialLargeBufferCount 200
InitialMediumBufferCount 480
InitialSmallBufferCount 640
LargeBufferSize 819200
MaxFastTransmit 64000
MediumBufferSize 150400
PriorityBoost 0
SmallBufferSize 12800
TransmitWorker 32
FastSendDatagramThreshold 4096
EnableFastRouteLookup 1
EnablePMTUDiscovery 1
IgnorePushBitOnReceives 0
GlobalMaxTcpWindowSize 64240
MaxFreeTcbs 8000
MaxHashTableSize 16384
MaxNormLookupMemory 5000000
SackOps 1
SynAttackProtect 1
Tcp13230pts 0
TcpLogLevel 1
TcpMaxDupAcks 2
TcpMaxHalfOpen 100
TcpMaxHalfOpenRetired 80
TcpRecevSegmentSize 1460
TcpSendSegmentSize 1460
TcpTimedWaitDelay 30
TcpUseRFC1122UrgentPointer 0
TcpWindowSize 64240
MaxConnectionsPer1_0Server 40
MaxConnectionsPerServer 20
DefaultTTL 128
DisableUserTOSSetting 0
TcpMaxDataRetransmissions 6
DefaultTOSValue 240

Thank you for the settings. Im sure they are correct. I guess everyone is missing my question. WEB 100 says increasing the current receive buffer (63.0 KB) will improve performance. Where is the increase in the receive buffer ?

what is your current speed

Depending on the site and the time of day, my download speeds will be between 2000kb and 2900kb. It hasnt been consistant recently. For a while I could count on a 2700kb - 2950kb all the time. Do you think I should raise my RWIN to 128480 and use windows scaling? Thank you for your reply.

no i wuld leave it low if it's inconsitant the more ppl that get cable the more bandwith gets used in that case a higher rwin could slow you down more.

OK. Thank you very much. Will leave it at this and see how it goes.