[PATCH 1/2] Client Taxonomy

[Nick Lowe]

> It’s reasonably common in commercial equipment that supports DHCP Snooping for RADIUS Interim-Update packets to be sent as soon as the AP learns the IP of the STA.  We could do something similar here. It’s fine for additional data to be added in later accounting packets so long as the Acct-Session-ID attribute stays consistent.

At Aerohive, we have implemented asynchronous, 'immediate'
Interim-Updates in our recent software releases so that as a
client/stations's IP becomes known or changes, we send an immediate
Interim-Update with that information. If the information is available
at the time that a Start is available, we will not send an
asynchronous Interim-Update.

(FWIW, we also now ensure that we only use DHCP snooped information to
populate the Framed-IP-Address AVP, rather than ARP sourced
information so that it's not unreliable / trivially spoofable.)