draft-ietf-bfd-seamless-base-02.txt		draft-ietf-bfd-seamless-base-03.txt
	Internet Engineering Task Force N. Akiya		Internet Engineering Task Force N. Akiya
	Internet-Draft C. Pignataro		Internet-Draft C. Pignataro
	Updates: 5880 (if approved) D. Ward		Updates: 5880 (if approved) D. Ward
	Intended status: Standards Track Cisco Systems		Intended status: Standards Track Cisco Systems
	Expires: February 2, 2015 M. Bhatia		Expires: February 24, 2015 M. Bhatia
	Ionos Networks		Ionos Networks
	P. K. Santosh		S. Pallagatti
	Juniper Networks		Juniper Networks
	August 1, 2014		August 23, 2014
	Seamless Bidirectional Forwarding Detection (S-BFD)		Seamless Bidirectional Forwarding Detection (S-BFD)
	draft-ietf-bfd-seamless-base-02		draft-ietf-bfd-seamless-base-03
	Abstract		Abstract
	This document defines a simplified mechanism to use Bidirectional		This document defines a simplified mechanism to use Bidirectional
	Forwarding Detection (BFD) with large portions of negotiation aspects		Forwarding Detection (BFD) with large portions of negotiation aspects
	eliminated, thus providing benefits such as quick provisioning as		eliminated, thus providing benefits such as quick provisioning as
	well as improved control and flexibility to network nodes initiating		well as improved control and flexibility to network nodes initiating
	the path monitoring.		the path monitoring.
	This document updates RFC5880.		This document updates RFC5880.
	skipping to change at page 1, line 47		skipping to change at page 1, line 47
	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 February 2, 2015.		This Internet-Draft will expire on February 24, 2015.
	Copyright Notice		Copyright Notice
	Copyright (c) 2014 IETF Trust and the persons identified as the		Copyright (c) 2014 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 26		skipping to change at page 2, line 26
	include Simplified BSD License text as described in Section 4.e of		include Simplified BSD License text as described in Section 4.e of
	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
	2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3		2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
	3. Seamless BFD Overview . . . . . . . . . . . . . . . . . . . . 4		3. Seamless BFD Overview . . . . . . . . . . . . . . . . . . . . 4
	4. S-BFD Discriminators . . . . . . . . . . . . . . . . . . . . 5		4. S-BFD Discriminators . . . . . . . . . . . . . . . . . . . . 5
	4.1. Discriminator Pools . . . . . . . . . . . . . . . . . . . 5		4.1. S-BFD Discriminator Uniqueness . . . . . . . . . . . . . 5
	4.2. S-BFD Discriminator Uniqueness . . . . . . . . . . . . . 6		4.2. Discriminator Pools . . . . . . . . . . . . . . . . . . . 6
	5. Reflector BFD Session . . . . . . . . . . . . . . . . . . . . 7		5. Reflector BFD Session . . . . . . . . . . . . . . . . . . . . 7
	6. State Variables . . . . . . . . . . . . . . . . . . . . . . . 7		6. State Variables . . . . . . . . . . . . . . . . . . . . . . . 7
	6.1. New State Variables . . . . . . . . . . . . . . . . . . . 7		6.1. New State Variables . . . . . . . . . . . . . . . . . . . 7
	6.2. State Variable Initialization and Maintenance . . . . . . 8		6.2. State Variable Initialization and Maintenance . . . . . . 8
	7. S-BFD Procedures . . . . . . . . . . . . . . . . . . . . . . 8		7. S-BFD Procedures . . . . . . . . . . . . . . . . . . . . . . 8
	7.1. S-BFD Packet Demultiplexing . . . . . . . . . . . . . . . 8		7.1. S-BFD Control Packet Demultiplexing . . . . . . . . . . . 8
	7.2. Initiator Procedures . . . . . . . . . . . . . . . . . . 8		7.2. Initiator Procedures . . . . . . . . . . . . . . . . . . 8
	7.2.1. SBFDInitiator State Machine . . . . . . . . . . . . . 9		7.2.1. SBFDInitiator State Machine . . . . . . . . . . . . . 9
	7.2.2. Details of S-BFD Packet Sent by SBFDInitiator . . . . 10		7.2.2. Details of S-BFD Control Packet Sent by SBFDInitiator 10
	7.3. Responder Procedures . . . . . . . . . . . . . . . . . . 10		7.3. Responder Procedures . . . . . . . . . . . . . . . . . . 10
	7.3.1. Responder Demultiplexing . . . . . . . . . . . . . . 10		7.3.1. Responder Demultiplexing . . . . . . . . . . . . . . 11
	7.3.2. Details of S-BFD Packet Sent by SBFDReflector . . . . 11		7.3.2. Details of S-BFD Control Packet Sent by SBFDReflector 11
	7.4. Diagnostic Values . . . . . . . . . . . . . . . . . . . . 11		7.4. Diagnostic Values . . . . . . . . . . . . . . . . . . . . 11
	7.5. The Poll Sequence . . . . . . . . . . . . . . . . . . . . 11		7.5. The Poll Sequence . . . . . . . . . . . . . . . . . . . . 11
	7.6. Control Plane Independent (C) . . . . . . . . . . . . . . 11		7.6. Control Plane Independent (C) . . . . . . . . . . . . . . 12
	7.7. Additional SBFDInitiator Behaviors . . . . . . . . . . . 12		7.7. Additional SBFDInitiator Behaviors . . . . . . . . . . . 12
	7.8. Additional SBFDReflector Behaviors . . . . . . . . . . . 12		7.8. Additional SBFDReflector Behaviors . . . . . . . . . . . 12
	8. Scaling Aspect . . . . . . . . . . . . . . . . . . . . . . . 13		8. Scaling Aspect . . . . . . . . . . . . . . . . . . . . . . . 13
	9. Co-existence with Classical BFD Sessions . . . . . . . . . . 13		9. Co-existence with Classical BFD Sessions . . . . . . . . . . 13
	10. S-BFD Echo Function . . . . . . . . . . . . . . . . . . . . . 13		10. S-BFD Echo Function . . . . . . . . . . . . . . . . . . . . . 13
	11. Security Considerations . . . . . . . . . . . . . . . . . . . 14		11. Security Considerations . . . . . . . . . . . . . . . . . . . 14
	12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15		12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
	13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15		13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15
	14. Contributing Authors . . . . . . . . . . . . . . . . . . . . 15		14. Contributing Authors . . . . . . . . . . . . . . . . . . . . 15
	15. References . . . . . . . . . . . . . . . . . . . . . . . . . 16		15. References . . . . . . . . . . . . . . . . . . . . . . . . . 16
	15.1. Normative References . . . . . . . . . . . . . . . . . . 16		15.1. Normative References . . . . . . . . . . . . . . . . . . 16
	15.2. Informative References . . . . . . . . . . . . . . . . . 16		15.2. Informative References . . . . . . . . . . . . . . . . . 16
	Appendix A. Loop Problem . . . . . . . . . . . . . . . . . . . . 16		Appendix A. Loop Problem . . . . . . . . . . . . . . . . . . . . 17
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
	1. Introduction		1. Introduction
	Bidirectional Forwarding Detection (BFD), [RFC5880] and related		Bidirectional Forwarding Detection (BFD), [RFC5880] and related
	documents, has efficiently generalized the failure detection		documents, has efficiently generalized the failure detection
	mechanism for multiple protocols and applications. There are some		mechanism for multiple protocols and applications. There are some
	improvements which can be made to better fit existing technologies.		improvements which can be made to better fit existing technologies.
	There is a possibility of evolving BFD to better fit new		There is a possibility of evolving BFD to better fit new
	technologies. This document focuses on several aspects of BFD in		technologies. This document focuses on several aspects of BFD in
	skipping to change at page 3, line 40		skipping to change at page 3, line 40
	2. Terminology		2. Terminology
	The reader is expected to be familiar with the BFD, IP and MPLS		The reader is expected to be familiar with the BFD, IP and MPLS
	terminologies and protocol constructs. This section describes		terminologies and protocol constructs. This section describes
	several new terminologies introduced by S-BFD.		several new terminologies introduced by S-BFD.
	o Classical BFD - BFD session types based on [RFC5880].		o Classical BFD - BFD session types based on [RFC5880].
	o S-BFD - Seamless BFD.		o S-BFD - Seamless BFD.
	o S-BFD packet - a BFD control packet destined to or sourced from		o S-BFD control packet - a BFD control packet for the S-BFD
	the well-known S-BFD port.		mechanism.
			o S-BFD echo packet - a BFD echo packet for the S-BFD mechanism.
			o S-BFD packet - a BFD control packet or a BFD echo packet.
	o Entity - a function on a network node that S-BFD mechanism allows		o Entity - a function on a network node that S-BFD mechanism allows
	remote network nodes to perform continuity test to. An entity can		remote network nodes to perform continuity test to. An entity can
	be abstract (ex: reachability) or specific (ex: IP addresses,		be abstract (ex: reachability) or specific (ex: IP addresses,
	router-IDs, functions).		router-IDs, functions).
	o SBFDInitiator - an S-BFD session on a network node that performs a		o SBFDInitiator - an S-BFD session on a network node that performs a
	continuity test to a remote entity by sending S-BFD packets.		continuity test to a remote entity by sending S-BFD packets.
	o SBFDReflector - an S-BFD session on a network node that listens		o SBFDReflector - an S-BFD session on a network node that listens
	for incoming S-BFD packets to local entities and generates		for incoming S-BFD control packets to local entities and generates
	response S-BFD packets.		response S-BFD control packets.
	o Reflector BFD session - synonymous with SBFDReflector.		o Reflector BFD session - synonymous with SBFDReflector.
	o S-BFD discriminator - a BFD discriminator allocated for a local		o S-BFD discriminator - a BFD discriminator allocated for a local
	entity and is being listened by an SBFDReflector.		entity and is being listened by an SBFDReflector.
	o BFD discriminator - a BFD discriminator allocated for an		o BFD discriminator - a BFD discriminator allocated for an
	SBFDInitiator.		SBFDInitiator.
	o Initiator - a network node hosting an SBFDInitiator.		o Initiator - a network node hosting an SBFDInitiator.
	o Responder - a network node hosting an SBFDReflector.		o Responder - a network node hosting an SBFDReflector.
	Below figure describes the relationship between S-BFD terminologies.		Below figure describes the relationship between S-BFD terminologies.
	+---------------------+ +---------------------+		+---------------------+ +------------------------+
	| Initiator | | Responder |		| Initiator | | Responder |
	| +-----------------+ | | +-----------------+ |		| +-----------------+ | | +-----------------+ |
	| | SBFDInitiator |--- S-BFD packet -->| SBFDReflector | |		| | SBFDInitiator |---S-BFD ctrl pkt----->| SBFDReflector | |
	| | +-------------+ | | | | +-------------+ | |		| | +-------------+ |<--S-BFD ctrl pkt------| +-------------+ | |
	| | | BFD discrim | | | | | |S-BFD discrim| | |		| | | BFD discrim | | | | | |S-BFD discrim| | |
	| | +-------------+ |<-- S-BFD packet ---| +----------^--+ | |		| | | | |---S-BFD echo pkt---+ | | | | |
	| +-----------------+ | | +------------|----+ |		| | +-------------+ | | | | | +----------^--+ | |
	| | | | |		| +-----------------+<-------------------+ +------------|----+ |
	| | | +---v----+ |		| | | | |
	| | | | Entity | |		| | | +---v----+ |
	| | | +--------+ |		| | | | Entity | |
	+---------------------+ +---------------------+		| | | +--------+ |
			+---------------------+ +------------------------+
	Figure 1: S-BFD Terminology Relationship		Figure 1: S-BFD Terminology Relationship
	3. Seamless BFD Overview		3. Seamless BFD Overview
	An S-BFD module on each network node allocates one or more S-BFD		An S-BFD module on each network node allocates one or more S-BFD
	discriminators for local entities, and creates a reflector BFD		discriminators for local entities, and creates a reflector BFD
	session. Allocated S-BFD discriminators may be advertised by		session. Allocated S-BFD discriminators may be advertised by
	applications (ex: OSPF/IS-IS). Required result is that applications,		applications (ex: OSPF/IS-IS). Required result is that applications,
	on other network nodes, possess the knowledge of the mapping from		on other network nodes, possess the knowledge of the mapping from
	remote entities to S-BFD discriminators. The reflector BFD session		remote entities to S-BFD discriminators. The reflector BFD session
	is to, upon receiving an S-BFD packet targeted to one of local S-BFD		is to, upon receiving an S-BFD control packet targeted to one of
	discriminator values, transmit a response S-BFD packet back to the		local S-BFD discriminator values, transmit a response S-BFD control
	initiator.		packet back to the initiator.
	Once above setup is complete, any network nodes, having the knowledge		Once above setup is complete, any network nodes, having the knowledge
	of the mapping from a remote entity to an S-BFD discriminator, can		of the mapping from a remote entity to an S-BFD discriminator, can
	quickly perform a continuity test to the remote entity by simply		quickly perform a continuity test to the remote entity by simply
	sending S-BFD packets with corresponding S-BFD discriminator value in		sending S-BFD control packets with corresponding S-BFD discriminator
	the "your discriminator" field.		value in the "your discriminator" field.
	For example:		For example:
	<------- IS-IS Network ------->		<------- IS-IS Network ------->
	+---------+		+---------+
	| |		| |
	A---------B---------C---------D		A---------B---------C---------D
	^ ^		^ ^
	| |		| |
	skipping to change at page 5, line 30		skipping to change at page 5, line 35
	123 456		123 456
	Figure 2: S-BFD for IS-IS Network		Figure 2: S-BFD for IS-IS Network
	The IS-IS with SystemID xxx (node A) allocates an S-BFD discriminator		The IS-IS with SystemID xxx (node A) allocates an S-BFD discriminator
	123, and advertises the S-BFD discriminator 123 in an IS-IS TLV. The		123, and advertises the S-BFD discriminator 123 in an IS-IS TLV. The
	IS-IS with SystemID yyy (node D) allocates an S-BFD discriminator		IS-IS with SystemID yyy (node D) allocates an S-BFD discriminator
	456, and advertises the S-BFD discriminator 456 in an IS-IS TLV. A		456, and advertises the S-BFD discriminator 456 in an IS-IS TLV. A
	reflector BFD session is created on both network nodes (node A and		reflector BFD session is created on both network nodes (node A and
	node D). When network node A wants to check the reachability to		node D). When network node A wants to check the reachability to
	network node D, node A can send an S-BFD packet, destined to node D,		network node D, node A can send an S-BFD control packet, destined to
	with "your discriminator" field set to 456. When the reflector BFD		node D, with "your discriminator" field set to 456. When the
	session on node D receives this S-BFD packet, then response S-BFD		reflector BFD session on node D receives this S-BFD control packet,
	packet is sent back to node A, which allows node A to complete the		then response S-BFD control packet is sent back to node A, which
	continuity test.		allows node A to complete the continuity test.
	4. S-BFD Discriminators		4. S-BFD Discriminators
	4.1. Discriminator Pools		4.1. S-BFD Discriminator Uniqueness
	This document defines following suggestions for discriminator		One important characteristics of an S-BFD discriminator is that it
	management on SBFDInitiator and SBFDReflector sessions, to minimize		MUST be unique within an administrative domain. If multiple network
	the collision between required S-BFD discriminators on a local		nodes allocated a same S-BFD discriminator value, then S-BFD control
	device.		packets falsely terminating on a wrong network node can result in a
			reflector BFD session to generate a response back, due to "your
			discriminator" matching. This is clearly not desirable. If only IP
			based S-BFD is considered, then it is possible for the reflector BFD
			session to require demultiplexing of incoming S-BFD control packets
			with combination of destination IP address and "your discriminator".
			Then S-BFD discriminator only has to be unique within a local node.
			However, S-BFD is a generic mechanism defined to run on wide range of
			environments: IP, MPLS, etc. For other transports like MPLS, because
			of the need to use non-routable IP destination address, it is not
			possible for reflector BFD session to demultiplex using IP
			destination address. With PHP, there may not be any incoming label
			stack to aid in demultiplexing either. Thus, S-BFD imposes a
			requirement that S-BFD discriminators MUST be unique within an
			administrative domain.
			4.2. Discriminator Pools
			This subsection describes a discriminator pool implementation
			technique to minimize S-BFD discriminator collisions. The result
			will allow an implementation to better satisfy the S-BFD
			discriminator uniqueness requirement defined in Section 4.1.
	o SBFDInitiator is to allocate a discriminator from the BFD		o SBFDInitiator is to allocate a discriminator from the BFD
	discriminator pool. If the system also supports classical BFD		discriminator pool. If the system also supports classical BFD
	that runs on [RFC5880], then the BFD discriminator pool SHOULD be		that runs on [RFC5880], then the BFD discriminator pool SHOULD be
	shared by SBFDInitiator sessions and classical BFD sessions.		shared by SBFDInitiator sessions and classical BFD sessions.
	o SBFDReflector is to allocate a discriminator from the S-BFD		o SBFDReflector is to allocate a discriminator from the S-BFD
	discriminator pool. The S-BFD discriminator pool SHOULD be a		discriminator pool. The S-BFD discriminator pool SHOULD be a
	separate pool than the BFD discriminator pool.		separate pool than the BFD discriminator pool.
	skipping to change at page 6, line 31		skipping to change at page 7, line 7
	Even when following the separate discriminator pool approach,		Even when following the separate discriminator pool approach,
	collision is still possible between one S-BFD application to another		collision is still possible between one S-BFD application to another
	S-BFD application, that may be using different values and algorithms		S-BFD application, that may be using different values and algorithms
	to derive S-BFD discriminator values. If the two applications are		to derive S-BFD discriminator values. If the two applications are
	using S-BFD for a same purpose (ex: network reachability), then the		using S-BFD for a same purpose (ex: network reachability), then the
	colliding S-BFD discriminator value can be shared. If the two		colliding S-BFD discriminator value can be shared. If the two
	applications are using S-BFD for a different purpose, then the		applications are using S-BFD for a different purpose, then the
	collision must be addressed. How such collisions are addressed is		collision must be addressed. How such collisions are addressed is
	outside the scope of this document.		outside the scope of this document.
	4.2. S-BFD Discriminator Uniqueness
	One important characteristics of an S-BFD discriminator is that it
	MUST be unique within an administrative domain. If multiple network
	nodes allocated a same S-BFD discriminator value, then S-BFD packets
	falsely terminating on a wrong network node can result in a reflector
	BFD session to generate a response back, due to "your discriminator"
	matching. This is clearly not desirable. If only IP based S-BFD is
	considered, then it is possible for the reflector BFD session to
	require demultiplexing of incoming S-BFD packets with combination of
	destination IP address and "your discriminator". Then S-BFD
	discriminator only has to be unique within a local node. However,
	S-BFD is a generic mechanism defined to run on wide range of
	environments: IP, MPLS, etc. For other transports like MPLS, because
	of the need to use non-routable IP destination address, it is not
	possible for reflector BFD session to demultiplex using IP
	destination address. With PHP, there may not be any incoming label
	stack to aid in demultiplexing either. Thus, S-BFD imposes a
	requirement that S-BFD discriminators MUST be unique within an
	administrative domain.
	5. Reflector BFD Session		5. Reflector BFD Session
	Each network node creates one or more reflector BFD sessions. This		Each network node creates one or more reflector BFD sessions. This
	reflector BFD session is a session which transmits S-BFD packets in		reflector BFD session is a session which transmits S-BFD control
	response to received S-BFD packets with "your discriminator" having		packets in response to received S-BFD control packets with "your
	S-BFD discriminators allocated for local entities. Specifically,		discriminator" having S-BFD discriminators allocated for local
	this reflector BFD session is to have following characteristics:		entities. Specifically, this reflector BFD session is to have
			following characteristics:
	o MUST NOT transmit any S-BFD packets based on local timer expiry.		o MUST NOT transmit any S-BFD packets based on local timer expiry.
	o MUST transmit an S-BFD packet in response to a received S-BFD		o MUST transmit an S-BFD control packet in response to a received
	packet having a valid S-BFD discriminator in the "your		S-BFD control packet having a valid S-BFD discriminator in the
	discriminator" field, unless prohibited by local policies (ex:		"your discriminator" field, unless prohibited by local policies
	administrative, security, rate-limiter, etc).		(ex: administrative, security, rate-limiter, etc).
	o MUST be capable of sending only two states: UP and ADMINDOWN.		o MUST be capable of sending only two states: UP and ADMINDOWN.
	One reflector BFD session may be responsible for handling received		One reflector BFD session may be responsible for handling received
	S-BFD packets targeted to all locally allocated S-BFD discriminators,		S-BFD control packets targeted to all locally allocated S-BFD
	or few reflector BFD sessions may each be responsible for subset of		discriminators, or few reflector BFD sessions may each be responsible
	locally allocated S-BFD discriminators. This policy is a local		for subset of locally allocated S-BFD discriminators. This policy is
	matter, and is outside the scope of this document.		a local matter, and is outside the scope of this document.
	Note that incoming S-BFD packets may be IPv4, IPv6 or MPLS based.		Note that incoming S-BFD control packets may be IPv4, IPv6 or MPLS
	How such S-BFD packets reach an appropriate reflector BFD session is		based. How such S-BFD control packets reach an appropriate reflector
	also a local matter, and is outside the scope of this document.		BFD session is also a local matter, and is outside the scope of this
			document.
	6. State Variables		6. State Variables
	S-BFD introduces new state variables, and modifies the usage of		S-BFD introduces new state variables, and modifies the usage of
	existing ones.		existing ones.
	6.1. New State Variables		6.1. New State Variables
	A new state variable is added to the base specification in support of		A new state variable is added to the base specification in support of
	S-BFD.		S-BFD.
	o bfd.SessionType: The type of this session. Allowable values are:		o bfd.SessionType: This is a variable introduced by
			[I-D.ietf-bfd-multipoint] and describes the type of this session.
			Allowable values for S-BFD sessions are:
	* SBFDInitiator - an S-BFD session on a network node that		* SBFDInitiator - an S-BFD session on a network node that
	performs a continuity test to a target entity by sending S-BFD		performs a continuity test to a target entity by sending S-BFD
	packets.		packets.
	* SBFDReflector - an S-BFD session on a network node that listens		* SBFDReflector - an S-BFD session on a network node that listens
	for incoming S-BFD packets to local entities and generates		for incoming S-BFD control packets to local entities and
	response S-BFD packets.		generates response S-BFD control packets.
	bfd.SessionType variable MUST be initialized to the appropriate type		bfd.SessionType variable MUST be initialized to the appropriate type
	when an S-BFD session is created.		when an S-BFD session is created.
	6.2. State Variable Initialization and Maintenance		6.2. State Variable Initialization and Maintenance
	Some state variables defined in section 6.8.1 of the BFD base		Some state variables defined in section 6.8.1 of the BFD base
	specification need to be initialized or manipulated differently		specification need to be initialized or manipulated differently
	depending on the session type.		depending on the session type.
	o bfd.DemandMode: This variable MUST be initialized to 1 for session		o bfd.DemandMode: This variable MUST be initialized to 1 for session
	type SBFDInitiator, and MUST be initialized to 0 for session type		type SBFDInitiator, and MUST be initialized to 0 for session type
	SBFDReflector.		SBFDReflector.
	7. S-BFD Procedures		7. S-BFD Procedures
	7.1. S-BFD Packet Demultiplexing		7.1. S-BFD Control Packet Demultiplexing
	Received BFD control packet MUST first be demultiplexed with		Received BFD control packet MUST first be demultiplexed with
	information from the lower layer (ex: destination UDP port,		information from the lower layer (ex: destination UDP port,
	associated channel type). If the packet is determined to be for an		associated channel type). If the packet is determined to be for an
	SBFDReflector, then the packet MUST be looked up to locate a		SBFDReflector, then the packet MUST be looked up to locate a
	corresponding SBFDReflector session based on the value from the "your		corresponding SBFDReflector session based on the value from the "your
	discriminator" field in the table describing S-BFD discriminators.		discriminator" field in the table describing S-BFD discriminators.
	If the packet is determined not to be for SBFDReflector, then the		If the packet is determined not to be for SBFDReflector, then the
	packet MUST be looked up to locate a corresponding SBFDInitiator		packet MUST be looked up to locate a corresponding SBFDInitiator
	session or classical BFD session based on the value from the "your		session or classical BFD session based on the value from the "your
	discriminator" field in the table describing BFD discriminators. If		discriminator" field in the table describing BFD discriminators. If
	the located session is a SBFDInitiator, then destination of the		the located session is a SBFDInitiator, then destination of the
	packet (i.e. destination IP address) SHOULD be validated to be for		packet (i.e. destination IP address) SHOULD be validated to be for
	self.		self.
	Details of the initial BFD control packet demultiplexing are		Details of the initial BFD control packet demultiplexing are
	described in relevant S-BFD data plane documents.		described in relevant S-BFD data plane documents.
	7.2. Initiator Procedures		7.2. Initiator Procedures
	S-BFD packets transmitted by an SBFDInitiator MUST set "your		S-BFD control packets transmitted by an SBFDInitiator MUST set "your
	discriminator" field to an S-BFD discriminator corresponding to the		discriminator" field to an S-BFD discriminator corresponding to the
	remote entity.		remote entity.
	Every SBFDInitiator MUST have a locally unique "my discriminator"		Every SBFDInitiator MUST have a locally unique "my discriminator"
	allocated from the BFD discriminator pool.		allocated from the BFD discriminator pool.
	Below ASCII art describes high level concept of continuity test using		Below ASCII art describes high level concept of continuity test using
	S-BFD. R2 allocates XX as the S-BFD discriminator for its network		S-BFD. R2 allocates XX as the S-BFD discriminator for its network
	reachability purpose, and advertises XX to neighbors. ASCII art		reachability purpose, and advertises XX to neighbors. ASCII art
	shows R1 and R4 performing a continuity test to R2.		shows R1 and R4 performing a continuity test to R2.
	skipping to change at page 9, line 19		skipping to change at page 9, line 27
	|v | v		|v | v
	R1 ==================== R2[*] ========= R3 ========= R4		R1 ==================== R2[*] ========= R3 ========= R4
	| ^ |^		| ^ |^
	| | ||		| | ||
	| +-- md=60/yd=XX (ping) --+|		| +-- md=60/yd=XX (ping) --+|
	| |		| |
	+---- md=XX/yd=60 (pong) ---+		+---- md=XX/yd=60 (pong) ---+
	[*] Reflector BFD session on R2.		[*] Reflector BFD session on R2.
	=== Links connecting network nodes.		=== Links connecting network nodes.
	--- S-BFD packet traversal.		--- S-BFD control packet traversal.
	Figure 3: S-BFD Continuity Test		Figure 3: S-BFD Continuity Test
	7.2.1. SBFDInitiator State Machine		7.2.1. SBFDInitiator State Machine
	An SBFDInitiator may be a persistent session on the initiator with a		An SBFDInitiator may be a persistent session on the initiator with a
	timer for S-BFD packet transmissions (stateful SBFDInitiator). An		timer for S-BFD control packet transmissions (stateful
	SBFDInitiator may also be a module, a script or a tool on the		SBFDInitiator). An SBFDInitiator may also be a module, a script or a
	initiator that transmits one or more S-BFD packets "when needed"		tool on the initiator that transmits one or more S-BFD control
	(stateless SBFDInitiator). For stateless SBFDInitiators, a complete		packets "when needed" (stateless SBFDInitiator). For stateless
	BFD state machine may not be applicable. For stateful		SBFDInitiators, a complete BFD state machine may not be applicable.
	SBFDInitiators, the states and the state machine described in		For stateful SBFDInitiators, the states and the state machine
	[RFC5880] will not function due to SBFDReflector session only sending		described in [RFC5880] will not function due to SBFDReflector session
	UP and ADMINDOWN states (i.e. SBFDReflector session does not send		only sending UP and ADMINDOWN states (i.e. SBFDReflector session
	INIT state). The following diagram provides the RECOMMENDED state		does not send INIT state). The following diagram provides the
	machine for stateful SBFDInitiators. The notation on each arc		RECOMMENDED state machine for stateful SBFDInitiators. The notation
	represents the state of the SBFDInitiator (as received in the State		on each arc represents the state of the SBFDInitiator (as received in
	field in the S-BFD packet) or indicates the expiration of the		the State field in the S-BFD control packet) or indicates the
	Detection Timer.		expiration of the Detection Timer.
	+--+		+--+
	ADMIN DOWN, | |		ADMIN DOWN, | |
	TIMER | V		TIMER | V
	+------+ UP +------+		+------+ UP +------+
	| |-------------------->| |----+		| |-------------------->| |----+
	| DOWN | | UP | | UP		| DOWN | | UP | | UP
	| |<--------------------| |<---+		| |<--------------------| |<---+
	+------+ ADMIN DOWN, +------+		+------+ ADMIN DOWN, +------+
	TIMER		TIMER
	skipping to change at page 10, line 13		skipping to change at page 10, line 25
	Figure 4: SBFDInitiator FSM		Figure 4: SBFDInitiator FSM
	Note that the above state machine is different from the base BFD		Note that the above state machine is different from the base BFD
	specification[RFC5880]. This is because the INIT state is no longer		specification[RFC5880]. This is because the INIT state is no longer
	applicable for the SBFDInitiator. Another important difference is		applicable for the SBFDInitiator. Another important difference is
	the transition of the state machine from the DOWN state to the UP		the transition of the state machine from the DOWN state to the UP
	state when a packet with State UP is received by the SBFDInitiator.		state when a packet with State UP is received by the SBFDInitiator.
	The definitions of the states and the events have the same meaning as		The definitions of the states and the events have the same meaning as
	in the base BFD specification [RFC5880].		in the base BFD specification [RFC5880].
	7.2.2. Details of S-BFD Packet Sent by SBFDInitiator		7.2.2. Details of S-BFD Control Packet Sent by SBFDInitiator
	S-BFD packets sent by an SBFDInitiator is to have following contents:		S-BFD control packets sent by an SBFDInitiator is to have following
			contents:
	o "my discriminator" assigned by local node.		o "my discriminator" assigned by local node.
	o "your discriminator" corresponding to a remote entity.		o "your discriminator" corresponding to a remote entity.
	o "State" MUST be set to a value describing local state.		o "State" MUST be set to a value describing local state.
	o "Desired Min TX Interval" MUST be set to a value describing local		o "Desired Min TX Interval" MUST be set to a value describing local
	desired minimum transmit interval.		desired minimum transmit interval.
	o "Required Min RX Interval" MUST be zero.		o "Required Min RX Interval" MUST be zero.
	o "Required Min Echo RX Interval" SHOULD be zero.		o "Required Min Echo RX Interval" SHOULD be zero.
	o "Detection Multiplier" MUST be set to a value describing locally		o "Detection Multiplier" MUST be set to a value describing locally
	used multiplier value.		used multiplier value.
	o Demand (D) bit MUST be set.		o Demand (D) bit MUST be set.
	7.3. Responder Procedures		7.3. Responder Procedures
	A network node which receives S-BFD packets transmitted by an		A network node which receives S-BFD control packets transmitted by an
	initiator is referred as responder. The responder, upon reception of		initiator is referred as responder. The responder, upon reception of
	S-BFD packets, is to perform necessary relevant validations described		S-BFD control packets, is to perform necessary relevant validations
	in [RFC5880], [RFC5881], [RFC5883], [RFC5884] and [RFC5885].		described in [RFC5880], [RFC5881], [RFC5883], [RFC5884] and
			[RFC5885].
	7.3.1. Responder Demultiplexing		7.3.1. Responder Demultiplexing
	When a responder receives an S-BFD packet, if the value in the "your		When a responder receives an S-BFD control packet, if the value in
	discriminator" field is not one of S-BFD discriminators allocated for		the "your discriminator" field is not one of S-BFD discriminators
	local entities, then this packet MUST NOT be considered for this		allocated for local entities, then this packet MUST NOT be considered
	mechanism. If the value in the "your discriminator" field is one of		for this mechanism. If the value in the "your discriminator" field
	S-BFD discriminators allocated for local entities, then the packet is		is one of S-BFD discriminators allocated for local entities, then the
	determined to be handled by a reflector BFD session responsible for		packet is determined to be handled by a reflector BFD session
	the S-BFD discriminator. If the packet was determined to be		responsible for the S-BFD discriminator. If the packet was
	processed further for this mechanism, then chosen reflector BFD		determined to be processed further for this mechanism, then chosen
	session is to transmit a response BFD control packet using procedures		reflector BFD session is to transmit a response BFD control packet
	described in Section 7.3.2, unless prohibited by local policies (ex:		using procedures described in Section 7.3.2, unless prohibited by
	administrative, security, rate-limiter, etc).		local policies (ex: administrative, security, rate-limiter, etc).
	7.3.2. Details of S-BFD Packet Sent by SBFDReflector		7.3.2. Details of S-BFD Control Packet Sent by SBFDReflector
	S-BFD packets sent by an SBFDReflector is to have following contents:		S-BFD control packets sent by an SBFDReflector is to have following
			contents:
	o "my discriminator" MUST be copied from received "your		o "my discriminator" MUST be copied from received "your
	discriminator".		discriminator".
	o "your discriminator" MUST be copied from received "my		o "your discriminator" MUST be copied from received "my
	discriminator".		discriminator".
	o "State" MUST be UP or ADMINDOWN. Clarification of reflector BFD		o "State" MUST be UP or ADMINDOWN. Clarification of reflector BFD
	session state is described in Section 7.8.		session state is described in Section 7.8.
	o "Desired Min TX Interval" MUST be copied from received "Desired		o "Desired Min TX Interval" MUST be copied from received "Desired
	Min TX Interval".		Min TX Interval".
	o "Required Min RX Interval" MUST be set to a value describing how		o "Required Min RX Interval" MUST be set to a value describing how
	skipping to change at page 11, line 35		skipping to change at page 11, line 50
	7.4. Diagnostic Values		7.4. Diagnostic Values
	Diagnostic value in both directions MAY be set to a certain value, to		Diagnostic value in both directions MAY be set to a certain value, to
	attempt to communicate further information to both ends. However,		attempt to communicate further information to both ends. However,
	details of such are outside the scope of this specification.		details of such are outside the scope of this specification.
	7.5. The Poll Sequence		7.5. The Poll Sequence
	Poll sequence MAY be used in both directions. The Poll sequence MUST		Poll sequence MAY be used in both directions. The Poll sequence MUST
	operate in accordance with [RFC5880]. An SBFDReflector MAY use the		operate in accordance with [RFC5880]. An SBFDReflector MAY use the
	Poll sequence to slow down that rate at which S-BFD packets are		Poll sequence to slow down that rate at which S-BFD control packets
	generated from an SBFDInitiator. This is done by the SBFDReflector		are generated from an SBFDInitiator. This is done by the
	using procedures described in Section 7.8 and setting the Poll (P)		SBFDReflector using procedures described in Section 7.8 and setting
	bit in the reflected S-BFD packet. The SBFDInitiator is to then send		the Poll (P) bit in the reflected S-BFD control packet. The
	the next S-BFD packet with the Final (F) bit set. If an		SBFDInitiator is to then send the next S-BFD control packet with the
	SBFDReflector receives an S-BFD packet with Poll (P) bit set, then		Final (F) bit set. If an SBFDReflector receives an S-BFD control
	the SBFDReflector MUST respond with an S-BFD packet with Poll (P) bit		packet with Poll (P) bit set, then the SBFDReflector MUST respond
	cleared and Final (F) bit set.		with an S-BFD control packet with Poll (P) bit cleared and Final (F)
			bit set.
	7.6. Control Plane Independent (C)		7.6. Control Plane Independent (C)
	Control plane independent (C) bit for an SBFDInitiator sending S-BFD		Control plane independent (C) bit for an SBFDInitiator sending S-BFD
	packets to a reflector BFD session MUST work according to [RFC5880].		control packets to a reflector BFD session MUST work according to
	Reflector BFD session also MUST work according to [RFC5880].		[RFC5880]. Reflector BFD session also MUST work according to
	Specifically, if reflector BFD session implementation does not share		[RFC5880]. Specifically, if reflector BFD session implementation
	fate with control plane, then response S-BFD packets transmitted MUST		does not share fate with control plane, then response S-BFD control
	have control plane independent (C) bit set. If reflector BFD session		packets transmitted MUST have control plane independent (C) bit set.
	implementation shares fate with control plane, then response S-BFD		If reflector BFD session implementation shares fate with control
	packets transmitted MUST NOT have control plane independent (C) bit		plane, then response S-BFD control packets transmitted MUST NOT have
	set.		control plane independent (C) bit set.
	7.7. Additional SBFDInitiator Behaviors		7.7. Additional SBFDInitiator Behaviors
	o If the SBFDInitiator receives a valid S-BFD packet in response to		o If the SBFDInitiator receives a valid S-BFD control packet in
	transmitted S-BFD packet to a remote entity, then the		response to transmitted S-BFD control packet to a remote entity,
	SBFDInitiator SHOULD conclude that S-BFD packet reached the		then the SBFDInitiator SHOULD conclude that S-BFD control packet
	intended remote entity.		reached the intended remote entity.
	o When a sufficient number of S-BFD packets have not arrived as they		o When a sufficient number of S-BFD packets have not arrived as they
	should, the SBFDInitiator SHOULD declare loss of reachability to		should, the SBFDInitiator SHOULD declare loss of reachability to
	the remote entity. The criteria for declaring loss of		the remote entity. The criteria for declaring loss of
	reachability and the action that would be triggered as a result		reachability and the action that would be triggered as a result
	are outside the scope of this document.		are outside the scope of this document.
	o Relating to above bullet item, it is critical for an		o Relating to above bullet item, it is critical for an
	implementation to understand the latency to/from the reflector BFD		implementation to understand the latency to/from the reflector BFD
	session on the responder. In other words, for very first S-BFD		session on the responder. In other words, for very first S-BFD
	packet transmitted by the SBFDInitiator, an implementation MUST		packet transmitted by the SBFDInitiator, an implementation MUST
	NOT expect response S-BFD packet to be received for time		NOT expect response S-BFD packet to be received for time
	equivalent to sum of latencies: initiator to responder and		equivalent to sum of latencies: initiator to responder and
	responder back to initiator.		responder back to initiator.
	o If the SBFDInitiator receives an S-BFD packet with Demand (D) bit		o If the SBFDInitiator receives an S-BFD control packet with Demand
	set, the packet MUST be discarded.		(D) bit set, the packet MUST be discarded.
	7.8. Additional SBFDReflector Behaviors		7.8. Additional SBFDReflector Behaviors
	o S-BFD packets transmitted by the SBFDReflector MUST have "Required		o S-BFD control packets transmitted by the SBFDReflector MUST have
	Min RX Interval" set to a value which expresses how many incoming		"Required Min RX Interval" set to a value which expresses how many
	S-BFD packets this SBFDReflector can handle. The SBFDReflector		incoming S-BFD control packets this SBFDReflector can handle. The
	can control how fast SBFInitiators will be sending S-BFD packets		SBFDReflector can control how fast SBFInitiators will be sending
	to self by ensuring "Required Min RX Interval" indicates a value		S-BFD control packets to self by ensuring "Required Min RX
	based on the current load.		Interval" indicates a value based on the current load.
	o If the SBFDReflector wishes to communicate to some or all		o If the SBFDReflector wishes to communicate to some or all
	SBFDInitiators that monitored local entity is "temporarily out of		SBFDInitiators that monitored local entity is "temporarily out of
	service", then S-BFD packets with "state" set to ADMINDOWN are		service", then S-BFD control packets with "state" set to ADMINDOWN
	sent to those SBFDInitiators. The SBFDInitiators, upon reception		are sent to those SBFDInitiators. The SBFDInitiators, upon
	of such packets, MUST NOT conclude loss of reachability to		reception of such packets, MUST NOT conclude loss of reachability
	corresponding remote entity, and MUST back off packet transmission		to corresponding remote entity, and MUST back off packet
	interval for the remote entity to an interval no faster than 1		transmission interval for the remote entity to an interval no
	second. If the SBFDReflector is generating a response S-BFD		faster than 1 second. If the SBFDReflector is generating a
	packet for a local entity that is in service, then "state" in		response S-BFD control packet for a local entity that is in
	response BFD control packets MUST be set to UP.		service, then "state" in response BFD control packets MUST be set
			to UP.
	o If an SBFDReflector receives an S-BFD packet with Demand (D) bit		o If an SBFDReflector receives an S-BFD control packet with Demand
	cleared, the packet MUST be discarded.		(D) bit cleared, the packet MUST be discarded.
	8. Scaling Aspect		8. Scaling Aspect
	This mechanism brings forth one noticeable difference in terms of		This mechanism brings forth one noticeable difference in terms of
	scaling aspect: number of SBFDReflector. This specification		scaling aspect: number of SBFDReflector. This specification
	eliminates the need for egress nodes to have fully active BFD		eliminates the need for egress nodes to have fully active BFD
	sessions when only one side desires to perform continuity tests.		sessions when only one side desires to perform continuity tests.
	With introduction of reflector BFD concept, egress no longer is		With introduction of reflector BFD concept, egress no longer is
	required to create any active BFD session per path/LSP/function		required to create any active BFD session per path/LSP/function
	basis. Due to this, total number of BFD sessions in a network is		basis. Due to this, total number of BFD sessions in a network is
	skipping to change at page 13, line 28		skipping to change at page 13, line 43
	9. Co-existence with Classical BFD Sessions		9. Co-existence with Classical BFD Sessions
	Initial packet demultiplexing requirement is described in		Initial packet demultiplexing requirement is described in
	Section 7.1. Because of this, S-BFD mechanism can co-exist with		Section 7.1. Because of this, S-BFD mechanism can co-exist with
	classical BFD sessions.		classical BFD sessions.
	10. S-BFD Echo Function		10. S-BFD Echo Function
	The concept of the S-BFD Echo function is similar to the BFD Echo		The concept of the S-BFD Echo function is similar to the BFD Echo
	function described in [RFC5880], packets are self-generated and self-		function described in [RFC5880]. S-BFD echo packets have the
	terminated after traversing a link/path. S-BFD echo packets are		destination of self, thus S-BFD echo packets are self-generated and
			self-terminated after traversing a link/path. S-BFD echo packets are
	expected to u-turn on the target node in the data plane and MUST NOT		expected to u-turn on the target node in the data plane and MUST NOT
	be processed by any reflector BFD sessions on the target node.		be processed by any reflector BFD sessions on the target node.
	When using the S-BFD Echo function, it is RECOMMENDED that:		When using the S-BFD Echo function, it is RECOMMENDED that:
	o Both S-BFD packets (with BFD control header) and S-BFD echo		o Both S-BFD control packets and S-BFD echo packets be sent.
	packets (implementation specific) be sent.
	o Both S-BFD packets and S-BFD echo packets have the same semantics		o Both S-BFD control packets and S-BFD echo packets have the same
	in the forward direction to reach the target node.		semantics in the forward direction to reach the target node.
	In other words, it is not preferable to send just S-BFD echo packets.		In other words, it is not preferable to send just S-BFD echo packets
	There are two reason behind this suggestion:		without also sending S-BFD control packets. There are two reasons
			behind this suggestion:
	o S-BFD packets can verify reachability to intended target node,		o S-BFD control packets can verify the reachability to intended
	which allows one to conclude that S-BFD echo packets are u-turning		target node, which allows one to have confidence that S-BFD echo
	on the expected target node.		packets are u-turning on the expected target node.
	o S-BFD packets can detect when the target node is going out of		o S-BFD control packets can detect when the target node is going out
	service (i.e. via receiving back ADMINDOWN state).		of service (i.e. via receiving back ADMINDOWN state).
	Implementations MAY set "Required Min Echo RX Interval" field to		The usage of the "Required Min Echo RX Interval" field is described
	indicate the rate which SBFDInitiator is sending S-BFD Echo packets		in Section 7.2.2 and Section 7.3.2. Because of the stateless nature
	(in ping) or the rate which SBFDReflector wants SBFDInitiators to		of SBFDReflector sessions, a value specified the "Required Min Echo
	send S-BFD Echo packets (in pong). However, this is likely more than		RX Interval" field in both directions is not very meaningful. Thus
	necessary for the S-BFD Echo function to operate. Therefore, it is		it is RECOMMENDED that the "Required Min Echo RX Interval" field
	RECOMMENDED that "Required Min Echo RX Interval" field simply be set		simply be set to zero in both directions.
	to zero in both directions.
	Additionally, following aspects are left as implementation details,		Following aspects of S-BFD Echo functions are left as implementation
	and are outside the scope of this document:		details, and are outside the scope of this document:
	o Format of the S-BFD Echo packet (ex: data beyond UDP header).		o Format of the S-BFD echo packet (ex: data beyond UDP header).
	o Procedures on when and how to use the S-BFD Echo function.		o Procedures on when and how to use the S-BFD Echo function.
	11. Security Considerations		11. Security Considerations
	Same security considerations as [RFC5880], [RFC5881], [RFC5883],		Same security considerations as [RFC5880], [RFC5881], [RFC5883],
	[RFC5884] and [RFC5885] apply to this document. Additionally,		[RFC5884] and [RFC5885] apply to this document. Additionally,
	implementing the following measures will strengthen security aspects		implementing the following measures will strengthen security aspects
	of the mechanism described by this document:		of the mechanism described by this document:
	skipping to change at page 14, line 38		skipping to change at page 15, line 6
	accepting the packet.		accepting the packet.
	o SBFDReflector MAY look at the Key ID		o SBFDReflector MAY look at the Key ID
	[I-D.ietf-bfd-generic-crypto-auth] in the incoming packet and		[I-D.ietf-bfd-generic-crypto-auth] in the incoming packet and
	verify the authentication data.		verify the authentication data.
	o SBFDReflector MUST accept the packet if authentication is		o SBFDReflector MUST accept the packet if authentication is
	successful.		successful.
	o SBFDReflector MUST compute the Authentication data and MUST use		o SBFDReflector MUST compute the Authentication data and MUST use
	the same sequence number that it received in the S-BFD packet that		the same sequence number that it received in the S-BFD control
	it is responding to.		packet that it is responding to.
	o SBFDInitiator MUST accept the S-BFD packet if it either comes with		o SBFDInitiator MUST accept the S-BFD control packet if it either
	the same sequence number as it had sent or it's within the window		comes with the same sequence number as it had sent or it's within
	that it finds acceptable (described in detail in		the window that it finds acceptable (described in detail in
	[I-D.ietf-bfd-generic-crypto-auth])		[I-D.ietf-bfd-generic-crypto-auth])
	Using the above method,		Using the above method,
	o SBFDReflector continue to remain stateless despite using security.		o SBFDReflector continue to remain stateless despite using security.
	o SBFDReflector are not susceptible to replay attacks as they always		o SBFDReflector are not susceptible to replay attacks as they always
	respond to S-BFD packets irrespective of the sequence number		respond to S-BFD control packets irrespective of the sequence
	carried.		number carried.
	o An attacker cannot impersonate the responder since the		o An attacker cannot impersonate the responder since the
	SBFDInitiator will only accept S-BFD packets that come with the		SBFDInitiator will only accept S-BFD control packets that come
	sequence number that it had originally used when sending the S-BFD		with the sequence number that it had originally used when sending
	packet.		the S-BFD control packet.
	12. IANA Considerations		12. IANA Considerations
	No action is required by IANA for this document.		No action is required by IANA for this document.
	13. Acknowledgements		13. Acknowledgements
	Authors would like to thank Jeffrey Haas, Greg Mirsky and Marc		Authors would like to thank Jeffrey Haas, Greg Mirsky and Marc
	Binderberger for performing thorough reviews and providing number of		Binderberger for performing thorough reviews and providing number of
	suggestions. Authors would like to thank Girija Raghavendra Rao, Les		suggestions. Authors would like to thank Girija Raghavendra Rao, Les
	skipping to change at page 16, line 33		skipping to change at page 16, line 42
	"Bidirectional Forwarding Detection (BFD) for MPLS Label		"Bidirectional Forwarding Detection (BFD) for MPLS Label
	Switched Paths (LSPs)", RFC 5884, June 2010.		Switched Paths (LSPs)", RFC 5884, June 2010.
	15.2. Informative References		15.2. Informative References
	[I-D.ietf-bfd-generic-crypto-auth]		[I-D.ietf-bfd-generic-crypto-auth]
	Bhatia, M., Manral, V., Zhang, D., and M. Jethanandani,		Bhatia, M., Manral, V., Zhang, D., and M. Jethanandani,
	"BFD Generic Cryptographic Authentication", draft-ietf-		"BFD Generic Cryptographic Authentication", draft-ietf-
	bfd-generic-crypto-auth-06 (work in progress), April 2014.		bfd-generic-crypto-auth-06 (work in progress), April 2014.
			[I-D.ietf-bfd-multipoint]
			Katz, D., Ward, D., and J. Networks, "BFD for Multipoint
			Networks", draft-ietf-bfd-multipoint-04 (work in
			progress), August 2014.
	[I-D.ietf-bfd-seamless-use-case]		[I-D.ietf-bfd-seamless-use-case]
	Aldrin, S., Bhatia, M., Mirsky, G., Kumar, N., and S.		Aldrin, S., Bhatia, M., Mirsky, G., Kumar, N., and S.
	Matsushima, "Seamless Bidirectional Forwarding Detection		Matsushima, "Seamless Bidirectional Forwarding Detection
	(BFD) Use Case", draft-ietf-bfd-seamless-use-case-00 (work		(BFD) Use Case", draft-ietf-bfd-seamless-use-case-00 (work
	in progress), June 2014.		in progress), June 2014.
	[RFC5885] Nadeau, T. and C. Pignataro, "Bidirectional Forwarding		[RFC5885] Nadeau, T. and C. Pignataro, "Bidirectional Forwarding
	Detection (BFD) for the Pseudowire Virtual Circuit		Detection (BFD) for the Pseudowire Virtual Circuit
	Connectivity Verification (VCCV)", RFC 5885, June 2010.		Connectivity Verification (VCCV)", RFC 5885, June 2010.
	skipping to change at page 18, line 27		skipping to change at page 18, line 36
	Dave Ward		Dave Ward
	Cisco Systems		Cisco Systems
	Email: wardd@cisco.com		Email: wardd@cisco.com
	Manav Bhatia		Manav Bhatia
	Ionos Networks		Ionos Networks
	Email: manav@ionosnetworks.com		Email: manav@ionosnetworks.com
	Santosh		Santosh Pallagatti
	Juniper Networks		Juniper Networks
	Email: santoshpk@juniper.net		Email: santoshpk@juniper.net
End of changes. 59 change blocks.
	190 lines changed or deleted		209 lines changed or added
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