Gee...  I might have put myself in a position that everyone is expecting
a good answer and I might not have one (I'm not a DTC specialist...).
Hope there are couple of those lurking out there (Bill.., Gerald.., Cathy.. -
help!).
 
Ok, what follows will not include DTC models (since I don't know which ones
would work) - and, hopefully I'm not missing too much - just trying to give
you an idea how I understand it's supposed to work.
 
How it works:
 
  On the HP3000 side, there needs to be a front-end DTC (some of the
  newer DTCs) that will receive the AFCP traffic from the HP3000, wrap
  it in IP headers and send it on to the router.  Similarly, the same
  DTC will receive the incoming IP datagrams from the router, remove
  the IP wrapping and forward the remaining AFCP packet to the HP3000.
 
  On the remote end, behind X-number of IP-routed networks, the DTC
  can be any old DTC (that understands IP wrapped AFCP).  Starting with
  DTC MGR version 14.2 DTC's will understand how to remove the IP wrapping
  and process the AFCP packet as the DTC's do.
 
Management (downside):
 
  DTC's are dummy devices at power on and will only gain their intelligence
  through a download from some box that knows how to manage DTCs (typically
  a DTC mgr PC).  At power-on they only know how to transmit a boot request
  (a DTC boot request) - and that boot request is not routable.
 
  I.e., you'll have to have a local DTC manager on every segment where you
  have DTC's in order to download those.  The download and DTC management
  protocols are not routable either - another reason for local DTC manager
  on every segment...  gets very expensive in highly distributed LANs...
  is somewhat better in situations where only a few number of remote LAN's
  come to question.  Still, ugly...
 
  There's something different about DTC16RX's - they apparently can be
  remotely managed from HP-UX openview machine and are again somehow smarter
  in terms of downloads - someone mentioned tftp protocol for downloading
  those - i.e. that would go across IP routed networks.
 
Hope this helps some.  DTC gurus out there, if I missed something or grossly
mistated something, please correct me (and everyone else will learn as well).
 
 
:-) Eero  (not a DTC brain...) - HP CSY Networking lab, NS services.