RE: [lwip-users] critical section protection + timer issues

[Tom C. Barker]

Could someone give me their advice on the following ftp-data network dump.

 

(1) I start out with a window of 8096 which decreases by 20 bytes on each

ACK until lwIP decides to ACK about 7300 bytes. I understand that this proper;

please correct me if I am wrong.

(2) At this point the snd_win drops to 2186: ( good since 2186 - (8096 - 7300 ) = 1400 )

(3) It continues to drop to just under my mss at which point it stays at 1450.

(4)The transfer is fine up to this point, but then the client begins to send data

at only 5 second intervals despite immediate lwIP ACKS.

 

Any suggestions on how I might be getting the client to avoid dropping

into this 5 second delay?

 

Any commentary on this whole transaction is greatly appreciated.

 

Thanks in advance,

Tom

 

*****************************************************

TCP      ftp-data > 2693 [SYN] Seq=119179 Ack=0 Win=8096 Len=0 MSS=1600
TCP      2693 > ftp-data [SYN, ACK] Seq=344358244 Ack=119180 Win=17520 Len=0 MSS=1460
TCP      ftp-data > 2693 [ACK] Seq=119180 Ack=344358245 Win=8096 Len=0
FTP-DATA FTP Data: 1460 bytes
FTP-DATA FTP Data: 1460 bytes
TCP      ftp-data > 2693 [ACK] Seq=119180 Ack=344361165 Win=8076 Len=0
FTP-DATA FTP Data: 1460 bytes
FTP-DATA FTP Data: 1460 bytes
FTP-DATA FTP Data: 1460 bytes
TCP      ftp-data > 2693 [ACK] Seq=119180 Ack=344364085 Win=8056 Len=0
FTP-DATA FTP Data: 1460 bytes
FTP-DATA FTP Data: 1460 bytes
FTP-DATA FTP Data: 1460 bytes
TCP      ftp-data > 2693 [ACK] Seq=119180 Ack=344367005 Win=8036 Len=0
FTP-DATA FTP Data: 1460 bytes
FTP-DATA FTP Data: 1460 bytes
FTP-DATA FTP Data: 1460 bytes
TCP      ftp-data > 2693 [ACK] Seq=119180 Ack=344367005 Win=8036 Len=0
TCP      ftp-data > 2693 [ACK] Seq=119180 Ack=344367005 Win=8036 Len=0
FTP-DATA FTP Data: 1460 bytes
TCP      ftp-data > 2693 [ACK] Seq=119180 Ack=344367005 Win=8036 Len=0
TCP      ftp-data > 2693 [ACK] Seq=119180 Ack=344367005 Win=8036 Len=0
TCP      ftp-data > 2693 [ACK] Seq=119180 Ack=344374305 Win=2186 Len=0
FTP-DATA FTP Data: 1460 bytes
TCP      ftp-data > 2693 [ACK] Seq=119180 Ack=344375765 Win=2176 Len=0
FTP-DATA FTP Data: 1460 bytes
...............

TCP      ftp-data > 2693 [ACK] Seq=119180 Ack=344477965 Win=1476 Len=0
FTP-DATA FTP Data: 1460 bytes
TCP      ftp-data > 2693 [ACK] Seq=119180 Ack=344479425 Win=1466 Len=0
FTP-DATA FTP Data: 1460 bytes
TCP      ftp-data > 2693 [ACK] Seq=119180 Ack=344480885 Win=1456 Len=0
FTP-DATA FTP Data: 1456 bytes
TCP      ftp-data > 2693 [ACK] Seq=119180 Ack=344482341 Win=1450 Len=0
FTP-DATA FTP Data: 1450 bytes
TCP      ftp-data > 2693 [ACK] Seq=119180 Ack=344483791 Win=1450 Len=0
FTP-DATA FTP Data: 1450 bytes