A thought I just had. How many folks have optical bypass switches on
their fddi connections? If a enough providers' equipment fail without
bypassing, the ring can get partitioned into different sections which
might explain some of this. Supposedly DRA's router is plugged into
the gigaswitch, but I don't have a gigaswitch manual to check what
happens with ring partitions.
Perhaps we're getting off of the nanog topical area here, but...
To the best of my knowledge, the fddi ring at mae-east is a
concentrator type ring, a to m / b to m type of thing... instead
of a fddi trunk type of ring with a to b and b to a.
MFS may have a number of concentrators hanging off of the Gigaswitch.
One of the nice things about a concentrated ring, if you will, is
that individual ports can come up and down... the ring transitions,
but when a node or nodes go down, the ring doesn't partition.
One note of humor about optical bypasses... although I've never used
them, I'm told they're less reliable than most fddi cards -- they end
up breaking and causing more problems then if you lived without them. =-)