Re: [DNA-BOF] Using L2 to provide Instantaneous Movement

[Bernard Aboba <aboba@internaut.com>]

> Right. I think there are two different ways to use L2 frames: to decide
> and anticipate movement, and on the other hand to enhance new link
> detection. In our draft, we focus on the new link detection and we
> consider (Re) Association Response as Link Up hint. At this point
> (association procedure), information on the MN about SSID and BSSID can
> be trusted.

Reassociation Response is *not* a "link up" hint in IEEE 802.11i, and
interpretting it as such causes major malfunctions.  In IEEE 802.11i the
link is not up until completion of the security negotiation (4-way
handshake).  Bringing the link up beforehand causes outgoing packets to be
dropped, so that the host will attempt reachability detection, will get no
answer and will then assume it is on the different subnet when this is not
the case.  Similarly, TCP will assume that an entire window of packets has
been dropped and will go into slow-start.

> I think to put all prefixes associated with an SSID can be introduced
> in Beacon and Probe Response in order to enhance the choice of the link
> attachment. This information should influence the choice of the next AP
> for a MN.

That's about all it can do, since some prefixes may not actually be
available to a particular station.