[c-nsp] IP SLA FTP doesn't finish the download?

[Luis Miguel Cruz Miranda]

Ok,

The situations is this...
Router 3825 running 12.4(24)T5 advipsrv., with several VRFs.
Each vrf is connected to a different modem, configured in a different
service.

The router has configured several IP SLAs... icmp, http, and off course ftp.
All those probes are being monitored over SNMP to obtain perfomance metrics.

The issue is related with the IP SLA FTP...
For an unknown reason is mostly failing, from the output of "ip sla
stats 50", the line "Number of failures" is not 0.

Well, said that, it could be and end-to-end issue... I discarded it,
there is no packet loss between the remote router and the ftp server.

The weird thing is...
I am downloading a 5MB.zip file which is exacly...
-rwxrwxrwx 1 aaaa aaaa 5242880 Apr 14  2011 5MB.zip

The log of the FTP server (pure-ftpd) is showing...

 cat /var/log/syslog | grep bytes
Oct  7 16:19:48 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/possiblesources.pcap downloaded  (1705710 bytes, 105.25KB/sec)
Oct  7 16:25:22 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2621440 bytes, 97.14KB/sec)
Oct  7 16:35:22 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2621440 bytes, 97.24KB/sec)
Oct  7 16:45:22 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2490368 bytes, 96.52KB/sec)
Oct  7 16:55:22 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2621440 bytes, 97.52KB/sec)
Oct  7 17:05:22 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2621440 bytes, 98.08KB/sec)
Oct  7 17:15:22 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2490368 bytes, 96.54KB/sec)
Oct  7 17:25:22 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2621440 bytes, 98.38KB/sec)
Oct  7 17:35:22 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2621440 bytes, 96.98KB/sec)
Oct  7 17:45:22 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2490368 bytes, 96.48KB/sec)
Oct  7 17:55:22 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2359296 bytes, 86.69KB/sec)
Oct  7 18:05:22 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2490368 bytes, 96.06KB/sec)
Oct  7 18:15:23 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2621440 bytes, 99.28KB/sec)
Oct  7 18:25:23 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2621440 bytes, 96.46KB/sec)
Oct  7 18:35:22 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2621440 bytes, 97.27KB/sec)
Oct  7 18:45:22 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2490368 bytes, 95.46KB/sec)
Oct  7 18:55:22 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2621440 bytes, 97.22KB/sec)
Oct  7 19:05:22 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2490368 bytes, 94.53KB/sec)
Oct  7 19:15:22 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2490368 bytes, 96.48KB/sec)
Oct  7 19:25:22 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2490368 bytes, 93.80KB/sec)
Oct  7 19:35:23 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2621440 bytes, 97.53KB/sec)
Oct  7 19:45:22 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2490368 bytes, 96.46KB/sec)
Oct  7 19:55:22 DEV012002 pure-ftpd: (aaaa at 172.30.96.162) [NOTICE]
//home/aaaa/5MB.zip downloaded  (2621440 bytes, 98.43KB/sec)

The router never downloads the complete file.
Futher more, the sniffer capture shows multiple RST, then FP, more RST,
in that order, from router to the ftp.

Other info is...
Timeout for SLA operation is big enough to download the file, that was
checked manually.
FTP passive is always used, and it is working fine too, checked manually
too.

any idea?