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The Generalized TTL Security Mechanism (GTSM) for the Label Distribution Protocol (LDP) (RFC6720) Disclosure Number: IPCOM000221059D
Original Publication Date: 2012-Aug-01
Included in the Prior Art Database: 2012-Aug-25
Document File: 16 page(s) / 18K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

C. Pignataro: AUTHOR [+2]


LDP [RFC5036] specifies two peer discovery mechanisms, a Basic one and an Extended one, both using UDP transport. The Basic Discovery mechanism is used to discover LDP peers that are directly connected at the link level, whereas the Extended Discovery mechanism is used to locate Label Switching Router (LSR) neighbors that are not directly connected at the link level. Once discovered, the LSR neighbors can establish the LDP peering session, using the TCP transport connection.

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This is the abbreviated version, containing approximately 16% of the total text.

Internet Engineering Task Force (IETF)                      C. Pignataro Request for Comments: 6720                                      R. Asati Updates: 5036                                              Cisco Systems Category: Standards Track                                    August 2012 ISSN: 2070-1721

            The Generalized TTL Security Mechanism (GTSM) for                  the Label Distribution Protocol (LDP)


   The Generalized TTL Security Mechanism (GTSM) describes a generalized    use of a packet's Time to Live (TTL) (IPv4) or Hop Limit (IPv6) to    verify that the packet was sourced by a node on a connected link,    thereby protecting the router's IP control plane from CPU    utilization-based attacks.  This technique improves security and is    used by many protocols.  This document defines the GTSM use for the    Label Distribution Protocol (LDP).

   This specification uses a bit reserved in RFC 5036 and therefore    updates RFC 5036.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force    (IETF).  It represents the consensus of the IETF community.  It has    received public review and has been approved for publication by the    Internet Engineering Steering Group (IESG).  Further information on    Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,    and how to provide feedback on it may be obtained at

Pignataro & Asati            Standards Track                    [Page 1]
 RFC 6720                      GTSM for LDP                   August 2012

 Copyright Notice

   Copyright (c) 2012 IETF Trust and the persons identified as the    document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal    Provisions Relating to IETF Documents    ( in effect on the date of    publication of this document.  Please review these documents    carefully, as they describe your rights and restrictions with respect    to this document.  Code Components extracted from this document must    include Simplified BSD License text as described in Section 4.e of    the Trust Legal Provisions and are provided without warranty as    described in the Simplified BSD License.

Table of Contents

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

      1.1. Specification of Requirements ..............................3

      1.2. Scope ......................................................3

   2. GTSM Procedures for...