[DNA] L2 notifications

[Alper Yegin <alper.yegin@samsung.com>]

This is an attempt to re-iterate the consensus we reached at the DNA
IETF60 meeting regarding L2-L3 interaction discussions. Please register
your opinion, otherwise we'll update the dna-l2-hints (name subject to
change :-) accordingly and move it forward.

Here we go:

"Link up" and "link down" events are conveyed to L3 via so-called
"link-layer event notifications". As part of this notification, in
addition to the event type, optional information associated with the
event can be provided. Specific to the link-type, this may be an IP
address (e.g., PPP [IPv4] with cdma2000, or PDP with GPRS), remote
interface identifier (e.g., PPP [IPv6] with cdma2000), or BSSID/SSID
(IEEE 802.11).

A L2 event notification and the associated information may be used as a
"hint" by their consumers (e.g., DNA) depending on the context they are
used, but this is very much consumer specific. So, downgrading them to
"hints" is fine in DNA solution space, but this should not be the
characterization as the information is generated and delivered to the
consumer.

Additionally we should add IEEE 802.3 to the I-D, for which volunteers
are sought to provide text for....

Cheers,

Alper