draft-ietf-bfd-seamless-ip-05.txt   draft-ietf-bfd-seamless-ip-06.txt 
Internet Engineering Task Force N. Akiya Internet Engineering Task Force C. Pignataro
Internet-Draft Big Switch Networks Internet-Draft D. Ward
Intended status: Standards Track C. Pignataro Intended status: Standards Track Cisco
Expires: November 5, 2016 D. Ward Expires: November 7, 2016 N. Akiya
Cisco Big Switch Networks
May 4, 2016 May 6, 2016
Seamless Bidirectional Forwarding Detection (S-BFD) for Seamless Bidirectional Forwarding Detection (S-BFD) for
IPv4, IPv6 and MPLS IPv4, IPv6 and MPLS
draft-ietf-bfd-seamless-ip-05 draft-ietf-bfd-seamless-ip-06
Abstract Abstract
This document defines procedures to use Seamless Bidirectional This document defines procedures to use Seamless Bidirectional
Forwarding Detection (S-BFD) for IPv4, IPv6 and MPLS environments. Forwarding Detection (S-BFD) for IPv4, IPv6 and MPLS environments.
Requirements Language Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on November 5, 2016. This Internet-Draft will expire on November 7, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. S-BFD UDP Port . . . . . . . . . . . . . . . . . . . . . . . 2 2. S-BFD UDP Port . . . . . . . . . . . . . . . . . . . . . . . 2
3. S-BFD Echo UDP Port . . . . . . . . . . . . . . . . . . . . . 3 3. S-BFD Echo UDP Port . . . . . . . . . . . . . . . . . . . . . 3
4. S-BFD Control Packet Demultiplexing . . . . . . . . . . . . . 3 4. S-BFD Control Packet Demultiplexing . . . . . . . . . . . . . 3
5. Initiator Procedures . . . . . . . . . . . . . . . . . . . . 3 5. Initiator Procedures . . . . . . . . . . . . . . . . . . . . 3
5.1. Details of S-BFD Control Packet Sent by SBFDInitiator . . 4 5.1. Details of S-BFD Control Packet Sent by SBFDInitiator . . 4
5.1.1. Target vs. Remote Entity (S-BFD Discriminator) . . . 4 5.1.1. Target vs. Remote Entity (S-BFD Discriminator) . . . 4
6. Responder Procedures . . . . . . . . . . . . . . . . . . . . 5 6. Responder Procedures . . . . . . . . . . . . . . . . . . . . 5
6.1. Details of S-BFD Control Packet Sent by SBFDReflector . . 5 6.1. Details of S-BFD Control Packet Sent by SBFDReflector . . 5
7. Security Considerations . . . . . . . . . . . . . . . . . . . 5 7. Security Considerations . . . . . . . . . . . . . . . . . . . 6
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 6 10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 7
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
11.1. Normative References . . . . . . . . . . . . . . . . . . 7 11.1. Normative References . . . . . . . . . . . . . . . . . . 7
11.2. Informative References . . . . . . . . . . . . . . . . . 7 11.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction 1. Introduction
Seamless Bidirectional Forwarding Detection (S-BFD), Seamless Bidirectional Forwarding Detection (S-BFD),
[I-D.ietf-bfd-seamless-base], defines a generalized mechanism to [I-D.ietf-bfd-seamless-base], defines a generalized mechanism to
allow network nodes to seamlessly perform continuity checks to remote allow network nodes to seamlessly perform continuity checks to remote
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5. Initiator Procedures 5. Initiator Procedures
S-BFD control packets are transmitted with IP header, UDP header and S-BFD control packets are transmitted with IP header, UDP header and
BFD control header ([RFC5880]). When S-BFD control packets are BFD control header ([RFC5880]). When S-BFD control packets are
explicitly label switched (i.e. not IP routed which happen to go over explicitly label switched (i.e. not IP routed which happen to go over
an LSP, but explicitly sent on a specific LSP), the former is an LSP, but explicitly sent on a specific LSP), the former is
prepended with a label stack. Note that this document does not make 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 a distinction between a single-hop S-BFD scenario and a multi-hop
S-BFD scenario, both scenarios are supported. S-BFD scenario, both scenarios are supported.
Necessary values in the BFD control headers are described in The necessary values in the BFD control headers are described in
[I-D.ietf-bfd-seamless-base]. Section 5.1 describes necessary values [I-D.ietf-bfd-seamless-base]. Section 5.1 describes necessary values
in the MPLS header, IP header and UDP header when an SBFDInitiator on in the MPLS header, IP header and UDP header when an SBFDInitiator on
the initiator is sending S-BFD control packets. the initiator is sending S-BFD control packets.
5.1. Details of S-BFD Control Packet Sent by SBFDInitiator 5.1. Details of S-BFD Control Packet Sent by SBFDInitiator
o Specifications common to both IP routed S-BFD control packets and o Specifications common to both IP routed S-BFD control packets and
explicitly label switched S-BFD control packets: explicitly label switched S-BFD control packets:
* Source IP address field of the IP header MUST be set to a local * Source IP address field of the IP header MUST be set to a local
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* UDP destination port MUST be set to a well-known UDP * UDP destination port MUST be set to a well-known UDP
destination port assigned for S-BFD: 7784. destination port assigned for S-BFD: 7784.
* UDP source port MUST NOT be set to 7784. * UDP source port MUST NOT be set to 7784.
o Specifications for IP routed S-BFD control packets: o Specifications for IP routed S-BFD control packets:
* Destination IP address field of the IP header MUST set to an IP * Destination IP address field of the IP header MUST set to an IP
address of the target. address of the target.
* TTL field of the IP header SHOULD be set to 255. * The TTL/Hop Limit field of the IP header SHOULD be set to 255.
o Specifications for explicitly label switched S-BFD control o Specifications for explicitly label switched S-BFD control
packets: packets:
* S-BFD control packets MUST have the label stack that is * S-BFD control packets MUST have the label stack that is
expected to reach the target. expected to reach the target.
* TTL field of the top most label SHOULD be 255. * TTL field of the top most label SHOULD be 255.
* The destination IP address MUST be chosen from the 127/8 range * The destination IP address MUST be chosen from the 127/8 range
for IPv4 and from the 0:0:0:0:0:FFFF:7F00/104 range for IPv6, for IPv4 and from the 0:0:0:0:0:FFFF:7F00:0/104 range for IPv6,
as with [RFC5884]. as with [RFC5884].
* TTL field of the IP header MUST be set to 1. * The TTL/Hop Limit field of the IP header MUST be set to 1.
5.1.1. Target vs. Remote Entity (S-BFD Discriminator) 5.1.1. Target vs. Remote Entity (S-BFD Discriminator)
Typically, an S-BFD control packet will have "your discriminator" Typically, an S-BFD control packet will have "your discriminator"
field corresponding to an S-BFD discriminator of the remote entity field corresponding to an S-BFD discriminator of the remote entity
located on the target network node defined by the destination IP located on the target network node defined by the destination IP
address or the label stack. It is, however, possible for an address or the label stack. It is, however, possible for an
SBFDInitiator to carefully set the "your discriminator" and TTL SBFDInitiator to carefully set the "your discriminator" and TTL
fields to perform a continuity test in the direction towards a fields to perform a continuity test in the direction towards a
target, but destined to a transit network node and not to the target target, but destined to a transit network node and not to the target
itself. itself.
Section 5.1 intentionally uses the word "target", instead of "remote Section 5.1 intentionally uses the word "target", instead of "remote
entity", to accommodate this possible S-BFD usage through TTL expiry. entity", to accommodate this possible S-BFD usage through TTL expiry.
This also requires S-BFD control packets not be dropped by the This also requires S-BFD control packets not be dropped by the
responder node due to TTL expiry. Thus implementations on the responder node due to TTL expiry. Thus implementations on the
responder MUST allow received S-BFD control packets taking TTL expiry responder MUST allow received S-BFD control packets taking TTL expiry
exception path to reach corresponding reflector BFD session. exception path to reach corresponding reflector BFD session. This is
an existing packet processing exception practice for OAM packets,
where the control plane further identifies the type of OAM by the
protocol and port numbers.
6. Responder Procedures 6. Responder Procedures
S-BFD control packets are IP routed back to the initiator, and will S-BFD control packets are IP routed back to the initiator, and will
have IP header, UDP header and BFD control header. If an have IP header, UDP header and BFD control header. If an
SBFDReflector receives an S-BFD control packet with UDP source port SBFDReflector receives an S-BFD control packet with UDP source port
as 7784, the packet MUST be discarded. Necessary values in the BFD as 7784, the packet MUST be discarded. Necessary values in the BFD
control header are described in [I-D.ietf-bfd-seamless-base]. control header are described in [I-D.ietf-bfd-seamless-base].
Section 6.1 describes necessary values in the IP header and UDP Section 6.1 describes necessary values in the IP header and UDP
header when an SBFDReflector on the responder is sending S-BFD header when an SBFDReflector on the responder is sending S-BFD
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o Destination IP address field of the IP header MUST be copied from o Destination IP address field of the IP header MUST be copied from
source IP address field of received S-BFD control packet. source IP address field of received S-BFD control packet.
o Source IP address field of the IP header MUST be set to a local IP o Source IP address field of the IP header MUST be set to a local IP
address that is expected to be visible by the initiator (i.e. not address that is expected to be visible by the initiator (i.e. not
IPv6 link-local address when the initiator is multiple hops away). IPv6 link-local address when the initiator is multiple hops away).
The source IP address SHOULD be copied from the destination IP The source IP address SHOULD be copied from the destination IP
address field of the received S-BFD control packet, except when it address field of the received S-BFD control packet, except when it
is from the 127/8 range for IPv4 or from the is from the 127/8 range for IPv4 or from the
0:0:0:0:0:FFFF:7F00/104 range for IPv6. 0:0:0:0:0:FFFF:7F00:0/104 range for IPv6.
o TTL field of the IP header MUST be set to 255. o The TTL/Hop Limit field of the IP header MUST be set to 255.
o UDP destination port MUST be copied from received UDP source port. o UDP destination port MUST be copied from received UDP source port.
o UDP source port MUST be copied from received UDP destination port. o UDP source port MUST be copied from received UDP destination port.
7. Security Considerations 7. Security Considerations
Security considerations for S-BFD are discussed in Security considerations for S-BFD are discussed in
[I-D.ietf-bfd-seamless-base]. Additionally, implementing the [I-D.ietf-bfd-seamless-base]. Additionally, implementing the
following measures will strengthen security aspects of the mechanism following measures will strengthen security aspects of the mechanism
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Address Spoofing", BCP 38, RFC 2827, DOI 10.17487/RFC2827, Address Spoofing", BCP 38, RFC 2827, DOI 10.17487/RFC2827,
May 2000, <http://www.rfc-editor.org/info/rfc2827>. May 2000, <http://www.rfc-editor.org/info/rfc2827>.
[RFC5884] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow, [RFC5884] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow,
"Bidirectional Forwarding Detection (BFD) for MPLS Label "Bidirectional Forwarding Detection (BFD) for MPLS Label
Switched Paths (LSPs)", RFC 5884, DOI 10.17487/RFC5884, Switched Paths (LSPs)", RFC 5884, DOI 10.17487/RFC5884,
June 2010, <http://www.rfc-editor.org/info/rfc5884>. June 2010, <http://www.rfc-editor.org/info/rfc5884>.
Authors' Addresses Authors' Addresses
Nobo Akiya
Big Switch Networks
Email: nobo.akiya.dev@gmail.com
Carlos Pignataro Carlos Pignataro
Cisco Systems, Inc. Cisco Systems, Inc.
Email: cpignata@cisco.com Email: cpignata@cisco.com
Dave Ward Dave Ward
Cisco Systems, Inc. Cisco Systems, Inc.
Email: wardd@cisco.com Email: wardd@cisco.com
Nobo Akiya
Big Switch Networks
Email: nobo.akiya.dev@gmail.com
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