Network Working Group C. Huitema, Chair
Request for Comments: 1481
Internet Architecture Board
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
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
. 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.
 Fuller, V., Li, T., Yu, J., and K. Varadhan, "Supernetting: an
Address Assignment and Aggregation Strategy", RFC 1338
cisco, Merit, OARnet, June 1992.
 Gerich, E., "Guidelines for management of IP Address Space", RFC 1466
, Merit, May 1993.
 Topolcic, C., "Schedule for IP Address Space Management
Guidelines", RFC 1367
, CNRI, October 1992.
 Rekhter, Y., and T. Li, "An Architecture for IP Address
Allocation with CIDR", Work in Progress, January 1993.
 Rekhter, Y., and C. Topolcic, "Exchanging Routing Information
across Provider/Subscriber Boundaries in CIDR environment", Work
in Progress, February 1993.
Security issues are not discussed in this memo.
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