An Appeal to the Internet Community to Return Unused IP Networks (Prefixes) to the IANA (RFC1917)
Original Publication Date: 1996-Feb-01
Included in the Prior Art Database: 2000-Sep-13
Internet Society Requests For Comment (RFCs)
This document is an appeal to the Internet community to return unused address space, i.e. any block of consecutive IP prefixes, to the Internet Assigned Numbers Authority (IANA) or any of the delegated registries, for reapportionment. Similarly an appeal is issued to providers to return unused prefixes which fall outside their customary address blocks to the IANA for reapportionment.
Network Working Group P. Nesser II
Request for Comments: 1917 Nesser & Nesser Consulting
BCP: 4 February 1996
Category: Best Current Practice
An Appeal to the Internet Community to Return
Unused IP Networks (Prefixes) to the IANA
Status of this Memo
This document specifies an Internet Best Current Practices for the
Internet Community, and requests discussion and suggestions for
improvements. Distribution of this memo is unlimited.
This document is an appeal to the Internet community to return unused
address space, i.e. any block of consecutive IP prefixes, to the
Internet Assigned Numbers Authority (IANA) or any of the delegated
registries, for reapportionment. Similarly an appeal is issued to
providers to return unused prefixes which fall outside their
customary address blocks to the IANA for reapportionment.
The Internet of today is a dramatically different network than the
original designers ever envisioned. It is the largest public data
network in the world, and continues to grow at an exponential rate
which doubles all major operational parameters every nine months. A
common metaphor in engineering is that every time a problem increases
in size by an order of magnitude, it becomes a new problem. This
adage has been true over the lifetime of the Internet.
The Internet is currently faced with two major operational problems
(amoung others). The first is the eventual exhaustion of the IPv4
address space and the second is the ability to route packets between
the large number of individual networks that make up the Internet.
The first problem is simply one of supply. There are only 2^32 IPv4
addresses available. The lifetime of that space is proportional to
the efficiency of its allocation and utilization. The second problem
is mainly a capacity problem. If the number of routes exceeds the
current capacity of the core Internet routers, some routes will be
dropped and sections of the Internet will no longer be able to
communicate with each other. The two problems are coupled and the
dominant one has, and will, change over time.
The initial design of IP had all addresses the same, eight bits of
network number and twenty four bits of host number. The expectation
was of a few, large, global networks. During the first spurts of
growth, especially with the invention of LAN technologies, it became
obvious that this assumption was wrong and the separation of the
address space into three classes (Class A for a few huge networks;
Class B for more, smaller networks; and Class C for those really
small LANs, with lots of network numbers) was implemented. Soon
subnets were added so sites with many small LANs could appear as a
single network to others, the first step at limiting routing table
size. And finally, CIDR was i...