From: The IESG <firstname.lastname@example.org>
To: IETF-Announce <email@example.com>
Cc: Internet Architecture Board <firstname.lastname@example.org>,
RFC Editor <email@example.com>,
mpls mailing list <firstname.lastname@example.org>,
mpls chair <email@example.com>
Subject: Document Action: 'LDP IGP Synchronization' to
The IESG has approved the following document:
- 'LDP IGP Synchronization '
<draft-ietf-mpls-ldp-igp-sync-05.txt> as an Informational RFC
This document is the product of the Multiprotocol Label Switching Working
The IESG contact persons are David Ward and Ross Callon.
A URL of this Internet-Draft is:
In certain networks there is a dependency on edge-to-edge Label
Switched Paths (LSPs) setup by Label Distribution Protocol (LDP),
e.g., networks that are used for MultiProtocol Label Switching
(MPLS) Virtual Private Network (VPN) applications. For such
applications it is not possible to rely on Internet Protocol (IP)
forwarding if the MPLS LSP is not operating appropriately.
Blackholing of labeled traffic can occur in situations where the
Interior Gateway Protocol (IGP) is operational on a link but LDP is
not operational on that link. While the link could still be used for
IP forwarding, it is not useful for MPLS forwarding, for example,
MPLS VPN; Border Gateway Protocol (BGP) route free core; or IP
address carried in the packet is out of the RFC 1918 [RFC 1918]
space. This document describes a mechanism to avoid traffic loss due
to this condition without introducing any protocol changes.
Working Group Summary
There are several known interoperable implementations of this
technology. The idea is now quite old.