[Discussion] Why is the outbound test so slow?

[Maurice Volaski <mvolaski@xxxxxxxxxxxx>]

I have a Mac running OS 9.2.2 with an Asante card, and it is very 
slow in the outbound test relative to inbound one. This ratio is 
present when the duplex settings are mismatched but in this instance, 
it seems to be OK. So is there another explanation?


WEB100 Enabled Statistics:
Checking for Middleboxes . . . . . . . . . . . . . . . . . .  Done
running 10s outbound test (client to server) . . . . . 11.04Kb/s
running 10s inbound test (server to client) . . . . . . 28.67Mb/s

        ------  Client System Details  ------
OS data: Name = Mac OS, Architecture = PowerPC, Version = 9.2.2
Java data: Vendor = Apple Computer, Inc., Version = 1.1.8

        ------  Web100 Detailed Analysis  ------
100 Mbps FastEthernet 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 = 4.05 msec; the Packet size = 
1460 Bytes; and
No packet loss - but packets arrived out-of-order 1.14% of the time
This connection is receiver limited 99.68% of the time.

    Web100 reports TCP negotiated the optional Performance Settings to:
RFC 2018 Selective Acknowledgment: OFF
RFC 896 Nagle Algorithm: ON
RFC 3168 Explicit Congestion Notification: OFF
RFC 1323 Time Stamping: OFF
RFC 1323 Window Scaling: OFF
Packet size is preserved End-to-End
Server IP addresses are preserved End-to-End
Client IP addresses are preserved End-to-End


WEB100 Kernel Variables:
Client: localhost/127.0.0.1
AckPktsIn: 10296
AckPktsOut: 0
BytesRetrans: 0
CongAvoid: 0
CongestionOverCount: 0
CongestionSignals: 0
CountRTT: 7380
CurCwnd: 33580
CurMSS: 1460
CurRTO: 210
CurRwinRcvd: 32768
CurRwinSent: 5840
CurSsthresh: 2147483647
DSACKDups: 0
DataBytesIn: 0
DataBytesOut: 35981700
DataPktsIn: 0
DataPktsOut: 24645
DupAcksIn: 118
ECNEnabled: 0
FastRetran: 0
MaxCwnd: 33580
MaxMSS: 1460
MaxRTO: 220
MaxRTT: 40
MaxRwinRcvd: 32768
MaxRwinSent: 5840
MaxSsthresh: 0
MinMSS: 1460
MinRTO: 210
MinRTT: 0
MinRwinRcvd: 648
MinRwinSent: 5840
NagleEnabled: 1
OtherReductions: 1
PktsIn: 10307
PktsOut: 24646
PktsRetrans: 0
X_Rcvbuf: 106496
SACKEnabled: 0
SACKsRcvd: 0
SendStall: 0
SlowStart: 22
SampleRTT: 0
SmoothedRTT: 10
X_Sndbuf: 106496
SndLimTimeRwin: 9999548
SndLimTimeCwnd: 26595
SndLimTimeSender: 5159
SndLimTransRwin: 4
SndLimTransCwnd: 4
SndLimTransSender: 1
SndLimBytesRwin: 35743720
SndLimBytesCwnd: 239440
SndLimBytesSender: 0
SubsequentTimeouts: 0
SumRTT: 29930
Timeouts: 0
TimestampsEnabled: 0
WinScaleRcvd: 0
WinScaleSent: 7
DupAcksOut: 0
StartTimeUsec: 759406
Duration: 10033677
c2sData: 5
c2sAck: 0
s2cData: 8
s2cAck: 9

Checking for mismatch condition
	(cwndtime > .3) [0.00>.3], (MaxSsthresh > 0) [0>0],
	 (PktsRetrans/sec > 2) [0>2], (estimate > 2) [2746.58>2]
Checking for mismatch on uplink
	(speed > 50 [28.69>50], (xmitspeed < 5) [0.01<5]
	(rwintime > .9) [0.99>.9], (loss < .01) [1.0E<.01]
Checking for excessive errors condition
	(loss/sec > .15) [1.0E>.15], (cwndtime > .6) [0.00>.6],
	(loss < .01) [1.0E<.01], (MaxSsthresh > 0) [0>0]
Checking for 10 Mbps link
	(speed < 9.5) [28.69<9.5], (speed > 3.0) [28.69>3.0]
	(xmitspeed < 9.5) [0.01<9.5] (loss < .01) [1.0E<.01], (link > 
0) [100>0]
Checking for Wireless link
	(sendtime = 0) [5.14=0], (speed < 5) [28.69<5]
	(Estimate > 50 [2746.58>50], (Rwintime > 90) [0.99>.90]
	(RwinTrans/CwndTrans = 1) [4/4=1], (link > 0) [100>0]
Checking for DSL/Cable Modem link
	(speed < 2) [28.69<2], (SndLimTransSender = 0) [1=0]
	 (SendTime = 0) [5.142901689132677E-4=0], (link > 0) [100>0]
Checking for half-duplex condition
	(rwintime > .95) [0.99>.95], (RwinTrans/sec > 30) [0.40>30],
	 (SenderTrans/sec > 30) [0.10>30], OR (link <= 10) [100<=10]
Checking for congestion
	(cwndtime > .02) [0.00>.02], (mismatch = 0) [0=0]
	(MaxSsthresh > 0) [0>0]

bw = 2746.58 based on packet size = 11Kbits, RTT = 4.05msec, and loss = 1.0E-6
The theoretical network limit is 2746.58 Mbps
The transmit buffer (104.0 KByte) limits the application to 200.34 Mbps
Your receive buffer (32.0 KByte) limits the application to 61.64 Mbps
The network based flow control limits the application to 63.17 Mbps

Client Data reports link is 'FastE', Client Acks report link is 'RTT'
Server Data reports link is 'OC-48', Server Acks report link is '10 Gig'
--

Maurice Volaski, mvolaski@xxxxxxxxxxxx
Computing Support, Rose F. Kennedy Center
Albert Einstein College of Medicine of Yeshiva University

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