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Cisco Systems UniDirectional Link Detection (UDLD) Protocol
RFC 5171

Approval announcement
Draft of message to be sent after approval:


From: The IESG <>
To: RFC Editor <>
Cc: The IESG <>, <>,
Subject: Re: Informational RFC to be: 

The IESG has no problem with the publication of 'Cisco Systems 
UniDirectional Link Detection (UDLD) Protocol' 
<draft-foschiano-udld-04.txt> as an Informational RFC. 

The IESG would also like the IRSG or RFC-Editor to review the comments in 
the datatracker 
related to this document and determine whether or not they merit 
incorporation into the document. Comments may exist in both the ballot 
and the comment log. 

The IESG contact person is Russ Housley.

A URL of this Internet-Draft is:

The process for such documents is described at

Thank you,

The IESG Secretary

Ballot Text

Technical Summary

  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

  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.

Working Group Summary

  This document is not the product of any IETF Working Group.  It was
  submitted directly to the RFC Editor by the authors.

Protocol Quality

  This document was reviewed by Joel Halpern and by the RFC Editor.

  At the request of the RFC Editor, the author changed the title and
  Abstract to make clear that this is a Cisco protocol, not an IETF


  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.

RFC Editor Note