Bidirectional Forwarding Detection (BFD) for IPv4 and IPv6 (Single Hop)
RFC 5881
Document | Type | RFC - Proposed Standard (June 2010; Errata) | |
---|---|---|---|
Authors | Dave Katz , David Ward | ||
Last updated | 2020-01-21 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized with errata bibtex | ||
Reviews | |||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 5881 (Proposed Standard) | |
Action Holders |
(None)
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||
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Ross Callon | ||
Send notices to | (None) |
Internet Engineering Task Force (IETF) D. Katz Request for Comments: 5881 D. Ward Category: Standards Track Juniper Networks ISSN: 2070-1721 June 2010 Bidirectional Forwarding Detection (BFD) for IPv4 and IPv6 (Single Hop) Abstract This document describes the use of the Bidirectional Forwarding Detection (BFD) protocol over IPv4 and IPv6 for single IP hops. 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 http://www.rfc-editor.org/info/rfc5881. Copyright Notice Copyright (c) 2010 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 (http://trustee.ietf.org/license-info) 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. Katz & Ward Standards Track [Page 1] RFC 5881 BFD for IPv4 and IPv6 (Single Hop) June 2010 1. Introduction One very desirable application for Bidirectional Forwarding Detection (BFD) [BFD] is to track IPv4 and IPv6 connectivity between directly connected systems. This could be used to supplement the detection mechanisms in routing protocols or to monitor router-host connectivity, among other applications. This document describes the particulars necessary to use BFD in this environment. Interactions between BFD and other protocols and system functions are described in the BFD Generic Applications document [BFD-GENERIC]. 1.1. Conventions Used in This Document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [KEYWORDS]. 2. Applications and Limitations This application of BFD can be used by any pair of systems communicating via IPv4 and/or IPv6 across a single IP hop that is associated with an incoming interface. This includes, but is not limited to, physical media, virtual circuits, and tunnels. Each BFD session between a pair of systems MUST traverse a separate network-layer path in both directions. This is necessary for demultiplexing to work properly, and also because (by definition) multiple sessions would otherwise be protecting the same path. If BFD is to be used in conjunction with both IPv4 and IPv6 on a particular path, a separate BFD session MUST be established for each protocol (and thus encapsulated by that protocol) over that link. If the BFD Echo function is used, transmitted packets are immediately routed back towards the sender on the interface over which they were sent. This may interact with other mechanisms that are used on the two systems that employ BFD. In particular, ingress filtering [BCP38] is incompatible with the way Echo packets need to be sent. Implementations that support the Echo function MUST ensure that ingress filtering is not used on an interface that employs the Echo function or make an exception for ingress filtering Echo packets. An implementation of the Echo function also requires Application Programming Interfaces (APIs) that may not exist on all systems. A system implementing the Echo function MUST be capable of sending Katz & Ward Standards Track [Page 2] RFC 5881 BFD for IPv4 and IPv6 (Single Hop) June 2010 packets to its own address, which will typically require bypassing the normal forwarding lookup. This typically requires access to APIs that bypass IP-layer functionality. Please note that BFD is intended as an Operations, Administration, and Maintenance (OAM) mechanism for connectivity check and connection verification. It is applicable for network-based services (e.g. router-to-router, subscriber-to-gateway, LSP/circuit endpoints, and service appliance failure detection). In these scenarios it isShow full document text