Re: [lwip-users] Slow response times in Microblaze Webserver example

[Kieran Mansley]

On Wed, 2006-09-27 at 13:05 -0300, address@hidden wrote:

> 064131 IP IBM-F3860BD49B6.1678 > 192.168.0.200.80: S 1324574079:1324574079(0) 
> win 65535 <mss 1460,nop,nop,sackOK>
> 025123 IP 192.168.0.200.80 > IBM-F3860BD49B6.1678: S 74879:74879(0) ack 
> 1324574080 win 16384 <mss 1460>
> 000024 IP IBM-F3860BD49B6.1678 > 192.168.0.200.80: . ack 1 win 65535
> 013976 IP IBM-F3860BD49B6.1678 > 192.168.0.200.80: P 1:31(30) ack 1 win 65535
> 032930 IP 192.168.0.200.80 > IBM-F3860BD49B6.1678: . ack 31 win 16354
> 027001 IP 192.168.0.200.80 > IBM-F3860BD49B6.1678: . ack 31 win 16384
> 033323 IP 192.168.0.200.80 > IBM-F3860BD49B6.1678: P 1:1261(1260) ack 31 win 
> 16384
> 015320 IP 192.168.0.200.80 > IBM-F3860BD49B6.1678: F 1261:1261(0) ack 31 win 
> 16384
> 000042 IP IBM-F3860BD49B6.1678 > 192.168.0.200.80: . ack 1262 win 64275
> 000098 IP IBM-F3860BD49B6.1678 > 192.168.0.200.80: F 31:31(0) ack 1262 win 
> 64275
> 171178 IP IBM-F3860BD49B6.1671 > 192.168.0.200.80: F 2601444881:2601444881(0) 
> ack 62994 win 64275
> 018375 IP 192.168.0.200.80 > IBM-F3860BD49B6.1671: R 2:2(0) ack 1 win 16384
> 181919 IP IBM-F3860BD49B6.1676 > 192.168.0.200.80: F 2886869572:2886869572(0) 
> ack 72265 win 64275
> 017283 IP 192.168.0.200.80 > IBM-F3860BD49B6.1676: R 2:2(0) ack 1 win 16384
> 000060 IP IBM-F3860BD49B6.1676 > 192.168.0.200.80: . ack 1 win 64275
> 026673 IP 192.168.0.200.80 > IBM-F3860BD49B6.1676: R 2:2(0) ack 1 win 16384
> 356558 IP IBM-F3860BD49B6.1662 > 192.168.0.200.80: F 2269257405:2269257405(0) 
> ack 47843 win 64275
> 016779 IP 192.168.0.200.80 > IBM-F3860BD49B6.1662: R 2:2(0) ack 1 win 16384
> 
> The server, Microblaze, sends the requested data then the FIN to which the 
> client, IBM, responds with an ack, then two FINs. Should there be an 
> acknowledgement of the first FIN by the server? Is the server getting 
> confused 
> and then sending the RST?

I can't comment on any of the performance issues you have with the
hardware as that's outside my field of expertise but the above TCP trace
I can help with.

The server is acknowledging the first FIN correctly - that's the packet
#9 in the above trace (line starts 000042).

The two FINs subsequently sent by the IBM are for two different
connections - one is from port 1678 (which seems to be the connection
you're discussing, and this is normal and in response to the FIN sent by
the server) and one is from port 1671 (which doesn't have any other
traffic in the above trace).  The Microblaze doesn't seem to know about
the 1671 port connection either as it sends a RST in response.  This is
the most likely reason for the RST anyway - if it receives a packet for
a connection it doesn't know about, a RST is the expected behaviour.

Hope that helps

Kieran