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Cisco Systems UniDirectional Link Detection (UDLD) Protocol (RFC5171)

IP.com Disclosure Number: IPCOM000169612D
Original Publication Date: 2008-Apr-01
Included in the Prior Art Database: 2008-Apr-24
Document File: 14 page(s) / 28K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

M. Foschiano: AUTHOR

Abstract

This document describes a Cisco Systems protocol that can be used to detect and disable unidirectional Ethernet fiber or copper links caused, for instance, by mis-wiring of fiber strands, interface malfunctions, media converters' faults, etc. It operates at Layer 2 in conjunction with IEEE 802.3's existing Layer 1 fault detection mechanisms.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 10% of the total text.

Network Working Group                                       M. Foschiano Request for Comments: 5171                                 Cisco Systems Category: Informational                                       April 2008

       Cisco Systems UniDirectional Link Detection (UDLD) Protocol

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.

IESG Note

   This RFC is not a candidate for any level of Internet Standard.  The    IETF disclaims any knowledge of the fitness of this RFC for any    purpose and in particular notes that the decision to publish is not    based on IETF review for such things as security, congestion control,    or inappropriate interaction with deployed protocols.  The RFC Editor    has chosen to publish this document at its discretion.  Readers of    this document should exercise caution in evaluating its value for    implementation and deployment.  See RFC 3932 for more information.

Abstract

   This document describes a Cisco Systems protocol that can be used to    detect and disable unidirectional Ethernet fiber or copper links    caused, for instance, by mis-wiring of fiber strands, interface    malfunctions, media converters' faults, etc.  It operates at Layer 2    in conjunction with IEEE 802.3's existing Layer 1 fault detection    mechanisms.

   This document explains the protocol objectives and applications,    illustrates the specific premises the protocol was based upon, and    describes the protocol architecture and related deployment issues to    serve as a possible base for future standardization.

 Foschiano                    Informational                      [Page 1]
 RFC 5171                          UDLD                        April 2008

 Table of Contents

   1. Introduction ....................................................2

   2. Protocol Objectives and Applications ............................3

   3. Protocol Design Premises ........................................4

   4. Protocol Background .............................................4

   5. Protocol Architecture ...........................................5

      5.1. The Basics .................................................5

      5.2. Neighbor Database Maintenance ..............................5

      5.3. Event-driven Detection and Echoing .........................6

      5.4. Event-based versus Event-less Detection ....................6

   6. Packet Format ...................................................7

      6.1. TLV Description ...................................