[Ecrit] Reset 2: Framework text

[Richard Barnes <rbarnes at bbn.com>]

Proposal (trying to be more concrete):

This document focuses on the case in which all three steps in the 
emergency calling process -- location configuration, call routing, and 
call placement -- are performed by the calling endpoint, with the 
endpoint's Access Service Provider supporting the process by providing 
location information.  Calls may be routed via an application-layer 
Communications Service Provider (e.g., a Voice Service Provider), but 
need not be.  The underlying protocols can also be used to support other 
models in which parts of the process are delegated to the Communications 
Service Provider.  This document does not address in detail either these 
models or interoperability issues between them and the model described here.