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IPv4 Address Behaviour Today (RFC2101)

IP.com Disclosure Number: IPCOM000002655D
Original Publication Date: 1997-Feb-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 11 page(s) / 29K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

B. Carpenter: AUTHOR [+3]

Abstract

The main purpose of this note is to clarify the current interpretation of the 32-bit IP version 4 address space, whose significance has changed substantially since it was originally defined. A short section on IPv6 addresses mentions the main points of similarity with, and difference from, IPv4.

This text was extracted from a ASCII Text document.
This is the abbreviated version, containing approximately 10% of the total text.

Network Working Group B. Carpenter

Request for Comments: 2101 J. Crowcroft

Category: Informational Y. Rekhter

IAB

February 1997

IPv4 Address Behaviour Today

Status of this Memo

This memo provides information for the Internet community. This memo

does not specify an Internet standard of any kind. Distribution of

this memo is unlimited.

Abstract

The main purpose of this note is to clarify the current

interpretation of the 32-bit IP version 4 address space, whose

significance has changed substantially since it was originally

defined. A short section on IPv6 addresses mentions the main points

of similarity with, and difference from, IPv4.

Table of Contents

1. Introduction.................................................1

2. Terminology..................................................2

3. Ideal properties.............................................3

4. Overview of the current situation of IPv4 addresses..........4

4.1. Addresses are no longer globally unique locators.........4

4.2. Addresses are no longer all temporally unique............6

4.3. Multicast and Anycast....................................7

4.4. Summary..................................................8

5. IPv6 Considerations..........................................8

ANNEX: Current Practices for IPv4 Address Allocation & Routing..9

Security Considerations........................................10

Acknowledgements...............................................11

References.....................................................11

Authors' Addresses.............................................13

1. Introduction

The main purpose of this note is to clarify the current

interpretation of the 32-bit IP version 4 address space, whose

significance has changed substantially since it was originally

defined in 1981 [RFC 791].

This clarification is intended to assist protocol designers, product

implementors, Internet service providers, and user sites. It aims to

avoid misunderstandings about IP addresses that can result from the

substantial changes that have taken place in the last few years, as a

result of the Internet's exponential growth.

A short section on IPv6 addresses mentions the main points of

similarity with, and difference from, IPv4.

2. Terminology

It is well understood that in computer networks, the concepts of

directories, names, network addresses, and routes are separate and

must be analysed separately [RFC 1498]. However, it is also

necessary to sub-divide the concept of "network address" (abbreviated

to "address" from here on) into at least two notions, namely

"identifier" and "locator". This was perhaps less well understood

...