Micro-loop Prevention by Introducing a Local Convergence Delay
RFC 8333, “Micro-loop Prevention by Introducing a Local Convergence Delay”, is a Proposed Standard document published in March 2018 by S. Litkowski, B. Decraene, C. Filsfils, P. Francois. The canonical text is published by the RFC Editor.
Abstract
This document describes a mechanism for link-state routing protocols that prevents local transient forwarding loops in case of link failure. This mechanism proposes a two-step convergence by introducing a delay between the convergence of the node adjacent to the topology change and the network-wide convergence.
Because this mechanism delays the IGP convergence, it may only be used for planned maintenance or when Fast Reroute (FRR) protects the traffic during the time between the link failure and the IGP convergence.
The mechanism is limited to the link-down event in order to keep the mechanism simple.
Simulations using real network topologies have been performed and show that local loops are a significant portion (>50%) of the total forwarding loops.
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 8333 is hosted at rfc-editor.org. Available in TXT,HTML.
- RFC 8332 Use of RSA Keys with SHA-256 and SHA-512 in the Secure Shell Protocol
- RFC 8334 Launch Phase Mapping for the Extensible Provisioning Protocol
- RFC 8331 RTP Payload for Society of Motion Picture and Television Engineers ST 291-1 Ancillary Data
- RFC 8335 PROBE: A Utility for Probing Interfaces
- RFC 8330 OSPF Traffic Engineering Link Availability Extension for Links with Variable Discrete Bandwidth
- RFC 8336 The ORIGIN HTTP/2 Frame
- RFC 8329 Framework for Interface to Network Security Functions
- RFC 8337 Model-Based Metrics for Bulk Transport Capacity