Re: IPv4 Address Flags

[Dennis Ferguson <dennis.c.ferguson%gmail.com@localhost>]

On 21 Apr, 2015, at 01:46 , Roy Marples <roy%marples.name@localhost> wrote:
> As discussed here [1], a few people voiced their opinion that they
> didn't like address removal when the carrier drops and would rather
> re-negotiate at carrier up. The first step of doing this is to add IPv6
> address flag semantics to IPv4 addresses.

To tell the truth I think this is fixing the problem in the wrong
spot.  I don't see a big difference between unplugging the ethernet
cable and plugging it back in, and unplugging the USB or Thunderbolt
ethernet dongle and plugging it back in, or hot-swapping the ethernet
line card out and replacing it with another.  If I have active protocol
connections I would like them to survive the interface itself going
away and coming back just as much as I would like them to survive
the special case of the carrier dropping and coming back.  Adding
complexity to deal only with the latter doesn't seem worth it.

I think it is better to let interface structures freely go and
come and instead address the issue higher up.  A protocol session
that is bound to a local address the box no longer has should no
longer be allowed to actually send packets with that address but
otherwise should be treated like it is getting ICMP unreachables in
response to the packets it is (not) sending.  If the local address
comes back it can pick up where it left off, if it doesn't it can
time out or the user can close it or it can persist doing nothing,
just like it would in the general case of the other end going
unreachable.

This seems to work no matter what it is that goes away and comes
back.

Dennis Ferguson