Label Edge Router Forwarding of IPv4 Option Packets
RFC 6178, “Label Edge Router Forwarding of IPv4 Option Packets”, is a Proposed Standard document published in March 2011 by D. Smith, J. Mullooly, W. Jaeger, T. Scholl. It updates RFC 3031. The canonical text is published by the RFC Editor.
Abstract
This document specifies how Label Edge Routers (LERs) should behave when determining whether to MPLS encapsulate an IPv4 packet with header options. Lack of a formal standard has resulted in different LER forwarding behaviors for IPv4 packets with header options despite being associated with a prefix-based Forwarding Equivalence Class (FEC). IPv4 option packets that belong to a prefix-based FEC, yet are forwarded into an IPv4/MPLS network without being MPLS- encapsulated, present a security risk against the MPLS infrastructure. Further, LERs that are unable to MPLS encapsulate IPv4 packets with header options cannot operate in certain MPLS environments. While this newly defined LER behavior is mandatory to implement, it is optional to invoke. [STANDARDS-TRACK]
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.
The canonical text of RFC 6178 is hosted at rfc-editor.org. Available in TXT,HTML.
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