[wplug] static DHCP via multiple interfaces

[Brandon Poyner]

On 2/17/07, Patrick Wagstrom <pwagstro at andrew.cmu.edu> wrote:

> From what I understand about IP and TCP this should be possible, as the
> OS will still know the proper sequence numbers to send for the
> connections, indicating that the connection can continue.  Anecdotally,
> it seems this works as when the wifi interface dies and comes back
> shortly afterward, my ssh sessions usually persist.

The WiFi connection dropping and then resuming where you left off is
normal.  TCP will keep trying for some time to get packet through and
the operating system also has a role here to keep the WiFi interface
configured even though the link is down.  For examle Windows 95/98
would close all established TCP connections if DUN disconnected, but
that might not be true for XP onward.  I still see Windows XP doing
that if you merely change the link speed and duplex for wired
ethernet.

Anyway, on to your other question about using the same IP for WiFi and
wired ethernet.  Michael Semcheski is basically right that you're just
going to have to try it.  I would think the connections would stay
open, I'm not totally sure what will happen in the routing tables when
DHCP is assigning the IP address and gateway.  You might have to play
with 'ip route ..." to see what's going on.  There is one other factor
here and that is the ARP tables.  There will be a slight delay as
ethernet discovers that the IP is now associated to a new MAC address.

-- 
Brandon
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