RFC 1676 (rfc1676) - Page 2 of 4

INFN Requirements for an IPng

RFC 1676             INFN Requirements for an IPng           August 1994


      - transparency to the final user: user applications should not be
        influenced.

      - flexibility: Simplify the suitability to new communication
        technology and to topology changes due to new services provided
        or to different users needs.

2. Application and Transport Level

   Starting from the top of the OSI model, we think that the users
   applications should not be influenced by the migration plan.  It
   means that the TCP (the transport layer) must maintain the same
   interfaces and services to the upper layers.  Anyway, it is also
   necessary to foresee the use of a different transport services. The
   possibility to use different transport should be offered to the
   applications.  Therefore a transport selector field is needed.

3. Network layer: service and address

   We assume that the network layer must continue to provide the same
   datagram service as IP does.  CLNS could be a solution and a reliable
   starting point for the IPng.  The main advantage is that this
   solution has been profitable tested and it is already available on
   many systems.  It is not, of course, deployed as widely as IPv4 is,
   since it is a newer technology, but it is widely configured and and
   there is already operational experience.  The corresponding address,
   the NSAP, is 20 bytes long.  It is long enough to scale the future
   data network environment.  Its hierarchical format can be organized
   in a really flexible way, satisfying hierarchical routing and policy
   based routing needs and simplifying the distributed administration
   and management.  A lot of work has been already done in the majority
   of the countries in order to define NSAP formats satisfying both the
   requirements of administrative delegation and routing performances.

4. Routing protocols

   We don't consider the decision about the routing protocol to be
   adopted for the IPng to be fundamental.  Even if this choice is very
   important to obtain good performances, the routing protocols can be
   changed or improved at any time, because there is no influence into
   the End Systems configuration.  Relationships between NSAP
   aggregation, hierarchical topology and hierarchical routing algorithm
   must be taken into account in IPng plan.  These issues could improve
   administration and topological flexibility of the IPng and solve the
   flat problem of the IPv4.  The IPng routing protocols should include
   policy-based features.  The IPv4 network topology is very complex and
   it will continue to enlarge during the transition. It would be very
   difficult or impossible to manage it without the "policy" tools.  The



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