Link-Layer Event Notifications for Detecting Network Attachments
RFC 4957
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]
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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
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