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
	skipping to change at page 1, line 40 ¶		skipping to change at page 1, line 40 ¶
	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
	skipping to change at page 2, line 22 ¶		skipping to change at page 2, line 22 ¶
	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
	skipping to change at page 4, line 5 ¶		skipping to change at page 4, line 5 ¶
	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
	skipping to change at page 4, line 30 ¶		skipping to change at page 4, line 30 ¶
	* 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
	skipping to change at page 5, line 37 ¶		skipping to change at page 5, line 40 ¶
	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
	skipping to change at page 8, line 7 ¶		skipping to change at page 8, line 12 ¶
	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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