We have a 9509 at the HQ site and a 9216 in the DR site connected via a DS3.
There are preiodic times when the fcip link will flap and come back up, sometimes it will continue for minutes and has happened for several hours with this error:
%PORT-5-IF_DOWN_TCP_MAX_RETRANSMIT: %$VSAN 50%$ Interface fcip1 is down(TCP conn. closed - retransmit failure)
originally the fcip profile was configured for 1000 max bandwidth and it was suggested to change it to something closer to the DS3 and this change was made:
fcip profile 1
ip address 10.1.2.1
tcp max-bandwidth-mbps 41 min-available-bandwidth-mbps 30 round-trip-time-ms 4
tcp send-buffer-size 5000
It made no difference at all. There is connectivity to the DR site during the flapping, I can see the bandwidth spike up, but there should be plenty to handle the load during the flapping.
Last night the serial interface of the DS3 was showing the tx load 65/255 and rx was 5/255 during the problem.
I am wondering, would the "min bandwidth" setting cause a "retransmit failure"?
That seems like more of a tcp/ip issue that an interface configuration issue, but I cannot find any reason for the flap.
No interface errors, but I have seen the ping response times go from 3ms to 25ms during this time, an indication of congestion somewhere.
Does anyone have any ideas?
There ar no errors on any of the interfaces for the DS3 or the fcip.