On Thu, 21 Jul 2011 11:35:37 -0500
Dan Williams [off-list ref] wrote:

quoted

For problem #2, shouldn't a new RS be sent whenever the interface
changes it's IFF_LOWER_UP bit?  IFF_LOWER_UP indicates a carrier on/off
event and thus indicates possible disconnect/reconnect to a new network.
I don't specifically know how it works now, but if RS isn't triggered
from IFF_LOWER_UP, I'd imagine that either (a) something didn't get
updated when IFF_LOWER_UP became how carrier was indicated in 2.6.17
(commit b00055aacdb172c05067612278ba27265fcd05ce) or (b) there's a
reason IFF_LOWER_UP isn'

IFF_RUNING is used to indicate carrier, IFF_LOWER_UP is for layered
devices like vlan's but is rarely used.