Hi Steve

I think I've tracked this down.  Can you apply the attached patch on top
of the one I posted before and re-run your test.

With both patches, I was able flip-flop the downed interface multiple times
and in all cases path failover completed and data flow resumed.

Here is the modified script I was running:

#!/bin/sh

net1="$1"
net2="$2"

flush() {
    iptables -F
    echo "Flush"
    exit
}

trap flush EXIT

while true; do
    # clear table
    iptables -F
    echo "flushed"
    sleep 5

    # block net1
    iptables -A INPUT -i "$net1" -p sctp -j DROP
    echo "set net1"
    sleep 5

    # clear table
    iptables -F
    echo "flushed"
    sleep 5

    # block net2
    iptables -A INPUT -i "$net2" -p sctp -j DROP
    echo "set net2"
    sleep 5
done

I was able to run this script for 10 minutes sustaining the message flow.

-vlad