RFC 1620 (rfc1620) - Page 1 of 19

Internet Architecture Extensions for Shared Media

Network Working Group                                          B. Braden
Request for Comments: 1620                                           ISI
Category: Informational                                        J. Postel
                                                                     ISI
                                                              Y. Rekhter
                                                            IBM Research
                                                                May 1994


           Internet Architecture Extensions for Shared Media

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 original Internet architecture assumed that each network is
   labeled with a single IP network number.  This assumption may be
   violated for shared media, including "large public data networks"
   (LPDNs).  The architecture still works if this assumption is
   violated, but it does not have a means to prevent multiple host-
   router and router-router hops through the shared medium.  This memo
   discusses alternative approaches to extending the Internet
   architecture to eliminate some or all unnecessary hops.

Table of Contents

   1. INTRODUCTION ..................................................  2
   2. THE ORIGINAL INTERNET ARCHITECTURE ............................  2
   3. THE PROBLEMS INTRODUCED BY SHARED MEDIA .......................  4
   4. SOME SOLUTIONS TO THE SM PROBLEMS .............................  7
      4.1  Hop-by-Hop Redirection ...................................  7
      4.2  Extended Routing ......................................... 11
      4.3  Extended Proxy ARP ....................................... 13
      4.4  Routing Query Messages ................................... 14
      4.5  Stale Routing Information ................................ 14
      4.6  Implications of Filtering (Firewalls) .................... 15
   5. SECURITY CONSIDERATIONS ....................................... 16
   6. CONCLUSIONS ................................................... 17
   7. ACKNOWLEDGMENTS ............................................... 17
   8. REFERENCES .................................................... 18
   Authors' Addresses ............................................... 19






Braden, Postel & Rekhter