RFC 6720 · PROPOSED STANDARD · 2012

The Generalized TTL Security Mechanism for the Label Distribution Protocol

Overview

RFC 6720, “The Generalized TTL Security Mechanism for the Label Distribution Protocol”, is a Proposed Standard document published in August 2012 by C. Pignataro, R. Asati. It updates RFC 5036. It has since been updated by RFC 7552. The canonical text is published by the RFC Editor.

Abstract

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. [STANDARDS-TRACK]

Abstract as published in the RFC, via rfc-editor.org.

What “Proposed Standard” means

An entry-level standards-track specification: stable, peer-reviewed and a solid basis for implementation, though it may still evolve before becoming an Internet Standard.

Read this RFC

The canonical text of RFC 6720 is hosted at rfc-editor.org. Available in TXT,HTML.

Relationships to other RFCs
This RFC updates
RFC 5036
Updated by
RFC 7552
Other RFCs from 2012

Who Is Online

In total there are 65 users online: 0 registered, 57 guests and 8 bots.

Most users ever online was 5,555 on 17 Jul 2026, 3:23 am.

Bots: AhrefsBot Applebot Baiduspider Bingbot Majestic Other Bot PetalBot SemrushBot

Users active in the past 15 minutes. Total registered members: 372