The IP over ATM Mailing List Archive by date

[Maryann Perez Maher <perez@isi.edu>]

] I thought where things stand is LLC must be supported and other
] encapsulations including null-encaps, tulip and tunic may be supported
] though I don't think RFC-1577 or the signalling RFC says anything
] about negociating the other encaps.  Only the framework doc says
] anything at all about them.
] 
] Curtis

The signaling RFC does discuss encapsulation negotiation, section 4 of 
Appendix D is devoted strictly to that topic. Quoting from that section:

  "b) VC-multiplexing (D.3.2) and LLC/SNAP (D.3.1)

   The calling ATM endsystem prefers to use VC multiplexing, but is
   willing to agree to use LLC/SNAP encapsulation instead, if the called
   ATM endsytem only supports LLC/SNAP."

To the best of my knowledge and in agreement with your thought, the ip-atm 
group decided to make LLC/SNAP the default encapsulation, i.e. MUST be 
supported, and allow null encapsulation and 1490 as optional.

Maryann