RFC 1519                 CIDR Address Strategy            September 1993


8.  Transitioning to a long term solution

   This solution does not change the Internet routing and addressing
   architectures.  Hence, transitioning to a more long term solution is
   not affected by the deployment of this plan.

9.  Conclusions

   We are all aware of the growth in routing complexity, and the rapid
   increase in allocation of network numbers.  Given the rate at which
   this growth is being observed, we expect to run out in a few short
   years.

   If the inter-domain routing protocol supports carrying network routes
   with associated masks, all of the major concerns demonstrated in this
   paper would be eliminated.

   One of the influential factors which permits maximal exploitation of
   the advantages of this plan is the number of people who agree to use
   it.

   If service providers start charging networks for advertising network
   numbers, this would be a very great incentive to share the address
   space, and hence the associated costs of advertising routes to
   service providers.

10.  Recommendations

   The NIC should begin to hand out large blocks of class C addresses to
   network service providers.  Each block must fall on bit boundaries
   and should be large enough to serve the provider for two years.
   Further, the NIC should distribute very large blocks to continental
   and national network service organizations to allow additional levels
   of aggregation to take place at the major backbone networks.  In
   addition, the NIC should modify its procedures for the IN-ADDR.ARPA
   domain to permit delegation along arbitrary octet boundaries.

   Service providers will further allocate power-of-two blocks of class
   C addresses from their address space to their subscribers.

   All organizations, including those which are multi-homed, should
   obtain address space from their provider (or one of their providers,
   in the case of the multi-homed).  These blocks should also fall on
   bit boundaries to permit easy route aggregation.

   To allow effective use of this new addressing plan to reduce
   propagated routing information, appropriate IETF WGs will specify the
   modifications needed to Inter-Domain routing protocols.



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RFC 1519                 CIDR Address Strategy            September 1993


   Implementation and deployment of these modifications should occur as
   quickly as possible.

11  References

   [1] Moy, J, "The OSPF Specification  Version 2", RFC 1247, Proteon,
       Inc., January 1991.

   [2] Rekhter, Y., and T. Li, "An Architecture for IP Address
       Allocation with CIDR", RFC 1518, T.J. Watson Research Center, IBM
       Corp., cisco Systems, September 1993.

12.  Security Considerations

   Security issues are not discussed in this memo.




































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RFC 1519                 CIDR Address Strategy            September 1993


13.  Authors' Addresses

   Vince Fuller
   BARRNet
   Pine Hall 115
   Stanford, CA, 94305-4122

   EMail: vaf@Stanford.EDU


   Tony Li
   cisco Systems, Inc.
   1525 O'Brien Drive
   Menlo Park, CA 94025

   EMail: tli@cisco.com


   Jessica (Jie Yun) Yu
   Merit Network, Inc.
   1071 Beal Ave.
   Ann Arbor, MI 48109

   EMail: jyy@merit.edu


   Kannan Varadhan
   Internet Engineer, OARnet
   1224, Kinnear Road,
   Columbus, OH 43212

   EMail: kannan@oar.net



















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