Network Working Group                                 C. Huitema, Chair
Request for Comments: 1481                  Internet Architecture Board
                                                              July 1993


           IAB Recommendation for an Intermediate Strategy to
                     Address the Issue of Scaling

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard.  Distribution of this memo is
   unlimited.

Recommendation

   Classless Inter-Domain Routing (CIDR) proposes strategies for address
   assignment of the existing IP address space with a view to conserve
   the address space and stem the explosive growth of routing tables in
   default-route-free routers run by transit routing domain providers
   [1].  CIDR is proposed as an immediate term strategy to extend the
   life of the current 32 bit IP address space.  This strategy presumes
   that a suitable long term solution is being addressed within the
   Internet technical community.

   The basic components of the CIDR plan are: management of the
   allocation of Internet address space and provision of a mechanism for
   aggregation of routing information.  The IP community has published
   several RFCs and Internet-Drafts which describe the architecture for
   IP address assignment and routing protocols which will promote the
   deployment of CIDR.  These documents have led to changes in the way
   network address are allocated and have prompted enhancements to the
   inter-domain and intra-domain routing protocols.

   With the CIDR prompted changes in the management of the allocation of
   the Internet address space, allocation of blocks of Class C numbers
   leads to an explosion of the routing tables.  So, it is important
   that the techniques for aggregating information in the routing
   protocols keep pace with the change in the allocation of IP numbers.

   The IAB endorses the CIDR architecture and its implementation.  In
   addition, the IAB supports the actions taken by the IANA and
   InterNIC, the router vendors, and the network operators to implement
   CIDR to address the scaling problem that we are facing with the
   growth of the Internet.

References

   [1] Fuller, V., Li, T., Yu, J., and K. Varadhan, "Supernetting: an
       Address Assignment and Aggregation Strategy", RFC 1338, BARRNet,
       cisco, Merit, OARnet, June 1992.

   [2] Gerich, E., "Guidelines for management of IP Address Space", RFC
       1466, Merit, May 1993.

   [3] Topolcic, C., "Schedule for IP Address Space Management
       Guidelines", RFC 1367, CNRI, October 1992.

   [4] Rekhter, Y., and T. Li, "An Architecture for IP Address
       Allocation with CIDR", Work in Progress, January 1993.

   [5] Rekhter, Y., and C. Topolcic, "Exchanging Routing Information
       across Provider/Subscriber Boundaries in CIDR environment", Work
       in Progress, February 1993.

Security Considerations

   Security issues are not discussed in this memo.

Author's Address

   Christian Huitema
   INRIA, Sophia-Antipolis
   2004 Route des Lucioles
   BP 109
   F-06561 Valbonne Cedex
   France

   Phone: +33 93 65 77 15
   EMail: Christian.Huitema@MIRSA.INRIA.FR