Link-Layer Event Notifications for Detecting Network Attachments
RFC 4957

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 06

Network Working Group                                   S. Krishnan, Ed.
Request for Comments: 4957                             Ericsson Research
Category: Informational                                     N. Montavont
                                                       GET ENST Bretagne
                                                              E. Njedjou
                                                          France Telecom
                                                           S. Veerepalli
                                                                Qualcomm
                                                           A. Yegin, Ed.
                                                                 Samsung
                                                             August 2007

    Link-Layer Event Notifications for Detecting Network Attachments

Status of This Memo

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

Copyright Notice

   Copyright (C) The IETF Trust (2007).

Abstract

   Certain network access technologies are capable of providing various
   types of link-layer status information to IP.  Link-layer event
   notifications can help IP expeditiously detect configuration changes.
   This document provides a non-exhaustive catalogue of information
   available from well-known access technologies.

Krishnan, et al.             Informational                      [Page 1]
RFC 4957                L2 Notifications for DNA             August 2007

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  Link-Layer Event Notifications . . . . . . . . . . . . . . . .  5
     3.1.  GPRS/3GPP  . . . . . . . . . . . . . . . . . . . . . . . .  6
     3.2.  cdma2000/3GPP2 . . . . . . . . . . . . . . . . . . . . . .  7
     3.3.  IEEE 802.11/WiFi . . . . . . . . . . . . . . . . . . . . .  8
     3.4.  IEEE 802.3 CSMA/CD . . . . . . . . . . . . . . . . . . . .  9
       3.4.1.  Link Integrity Tests in 802.3 Networks . . . . . . . . 10
       3.4.2.  IEEE 802.1D Bridging and Its Effects on Link-layer
               Event Notifications  . . . . . . . . . . . . . . . . . 11
       3.4.3.  802.1AB Link-Layer Discovery Protocol  . . . . . . . . 12
       3.4.4.  Other Heuristics . . . . . . . . . . . . . . . . . . . 13
       3.4.5.  Summary  . . . . . . . . . . . . . . . . . . . . . . . 13
   4.  Security Considerations  . . . . . . . . . . . . . . . . . . . 13
   5.  Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 14
   6.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14
   7.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
     7.1.  Normative References . . . . . . . . . . . . . . . . . . . 14
     7.2.  Informative References . . . . . . . . . . . . . . . . . . 16

Krishnan, et al.             Informational                      [Page 2]
RFC 4957                L2 Notifications for DNA             August 2007

1.  Introduction

   It is not an uncommon occurrence for a node to change its point of
   attachment to the network.  This can happen due to mobile usage
   (e.g., a mobile phone moving among base stations) or nomadic usage
   (e.g., road-warrior case).

   A node changing its point of attachment to the network may end up
   changing its IP subnet and therefore require reconfiguration of IP-
   layer parameters, such as IP address, default gateway information,
   and DNS server address.  Detecting the subnet change can usually use
   network-layer indications (such as a change in the advertised
   prefixes for IPv6).  But such indications may not be always available
   (e.g., Detecting Network Attachment in IPv6 (DNAv6)) to the node upon
   changing its point of attachment.

   Link-layer event notifications can help IP expeditiously detect
   configuration changes.  This document provides a non-exhaustive
   catalog of information available from some access technologies, and
   discusses the interpretation of this information at the IP layer.
   This document is not intended to specify or change the behavior of
   these access technologies in any manner.

   Additional information can be conveyed along with the event, such as
   the identifier of the network attachment point (e.g., IEEE 802.11
   Basic Service Set Identification (BSSID) and Service Set Identifier
   (SSID)), or network-layer configuration parameters obtained via the
   link-layer attachment process if available.  It is envisaged that
   such event notifications can in certain circumstances be used to
   expedite the inter-subnet movement detection and reconfiguration
   process.  For example, the notification indicating that the node has
   established a new link-layer connection may be used for immediately