One document matched: draft-akiya-bfd-seamless-ip-03.txt
Differences from draft-akiya-bfd-seamless-ip-02.txt
Internet Engineering Task Force N. Akiya
Internet-Draft C. Pignataro
Intended status: Standards Track D. Ward
Expires: December 28, 2014 Cisco Systems
June 26, 2014
Seamless Bidirectional Forwarding Detection (S-BFD) for
IPv4, IPv6 and MPLS
draft-akiya-bfd-seamless-ip-03
Abstract
This document defines procedures to use Seamless Bidirectional
Forwarding Detection (S-BFD) for IPv4, IPv6 and MPLS environments.
Requirements Language
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 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 28, 2014.
Copyright Notice
Copyright (c) 2014 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
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Internet-Draft Seamless BFD for IP June 2014
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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Initiator Procedures . . . . . . . . . . . . . . . . . . . . 2
2.1. Details of S-BFD Packet Sent by SBFDInitiator . . . . . . 3
2.2. Target vs. Remote Entity (S-BFD Discriminator) . . . . . 3
3. Responder Procedures . . . . . . . . . . . . . . . . . . . . 4
3.1. Details of S-BFD Packet Sent by SBFDReflector . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
7. Contributing Authors . . . . . . . . . . . . . . . . . . . . 4
8. Normative References . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
Seamless Bidirectional Forwarding Detection (S-BFD),
[I-D.ietf-bfd-seamless-base], defines a generalized mechanism to
allow network nodes to seamlessly perform connectivity checks to
remote entities. This document defines necessary procedures to use
S-BFD on IPv4, IPv6 and MPLS environments.
The reader is expected to be familiar with the IP, MPLS BFD and S-BFD
terminologies and protocol constructs.
2. Initiator Procedures
S-BFD packets are transmitted with IP header, UDP header and BFD
control header ([RFC5880]). When S-BFD packets are explicitly label
switched, the former is prepended with a label stack. Note that this
document does not make a distinction between a single-hop S-BFD
scenario and a multi-hop S-BFD scenario, both scenarios are
supported.
Necessary values in the UDP and BFD control headers are described in
[I-D.ietf-bfd-seamless-base]. Section 2.1 describes necessary values
in the IP and MPLS headers when an SBFDInitiator on the initiator is
sending S-BFD packets.
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2.1. Details of S-BFD Packet Sent by SBFDInitiator
o Specification common to both IP routed S-BFD packets and
explicitly label switched S-BFD packets:
* Source IP address field of the IP header MUST be set to a local
IP address.
o Specification for IP routed S-BFD packets:
* Destination IP address field of the IP header MUST set to an IP
address of the target.
* TTL field of the IP header SHOULD be set to 255.
o Specification for explicitly label switched S-BFD packets:
* S-BFD packets MUST have the label stack that is expected to
reach the target.
* TTL field of the top most label SHOULD be 255.
* Destination IP address field of the IP header MUST be set to
127/8 for IPv4 and 0:0:0:0:0:FFFF:7F00/104 for IPv6.
* TTL field of the IP header MUST be set to 1.
Ed-Note: Discuss whether we want a new associated channel type for
S-BFD.
2.2. Target vs. Remote Entity (S-BFD Discriminator)
Typically, an S-BFD packet will have "your discriminator" field
corresponding to an S-BFD discriminator of the remote entity located
on the target network node defined by the destination IP address or
the label stack. It is, however, possible for an SBFDInitiator to
carefully set "your discriminator" and TTL fields to perform a
connectivity test towards a target but to a transit network node.
Section 2.1 intentionally uses the word "target", instead of "remote
entity", to accommodate this possible S-BFD usage through TTL expiry.
This also requires S-BFD packets not be dropped by the responder node
due to TTL expiry. Thus implementations on the responder MUST allow
received S-BFD packets taking TTL expiry exception path to reach
corresponding reflector BFD session.
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3. Responder Procedures
S-BFD packets are IP routed back to the initiator, and will have IP
header, UDP header and BFD control header. Necessary values in the
UDP and BFD control headers are described in
[I-D.ietf-bfd-seamless-base]. Section 3.1 describes necessary values
in the IP header when an SBFDReflector on the responder is sending
S-BFD packets.
3.1. Details of S-BFD Packet Sent by SBFDReflector
o Destination IP address field of the IP header MUST be copied from
source IP address field of received S-BFD packet.
o Source IP address field of the IP header MUST be set to a local IP
address.
o TTL field of the IP header SHOULD be set to 255.
4. Security Considerations
Security considerations for S-BFD are discussed in
[I-D.ietf-bfd-seamless-base].
5. IANA Considerations
No action is required by IANA for this document.
6. Acknowledgements
Authors would like to thank Marc Binderberger from Cisco Systems for
providing valuable comments.
7. Contributing Authors
Tarek Saad
Cisco Systems
Email: tsaad@cisco.com
Siva Sivabalan
Cisco Systems
Email: msiva@cisco.com
Nagendra Kumar
Cisco Systems
Email: naikumar@cisco.com
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8. Normative References
[I-D.ietf-bfd-seamless-base]
Akiya, N., Pignataro, C., Ward, D., Bhatia, M., and J.
Networks, "Seamless Bidirectional Forwarding Detection
(S-BFD)", draft-ietf-bfd-seamless-base-00 (work in
progress), June 2014.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD)", RFC 5880, June 2010.
Authors' Addresses
Nobo Akiya
Cisco Systems
Email: nobo@cisco.com
Carlos Pignataro
Cisco Systems
Email: cpignata@cisco.com
Dave Ward
Cisco Systems
Email: wardd@cisco.com
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