draft-ietf-bfd-on-lags-02.txt		draft-ietf-bfd-on-lags-03.txt
	Network Working Group M. Bhatia, Ed.		Network Working Group M. Bhatia, Ed.
	Internet-Draft Alcatel-Lucent		Internet-Draft Alcatel-Lucent
	Intended status: Standards Track M. Chen, Ed.		Intended status: Standards Track M. Chen, Ed.
	Expires: May 15, 2014 Huawei Technologies		Expires: June 3, 2014 Huawei Technologies
	S. Boutros, Ed.		S. Boutros, Ed.
	M. Binderberger, Ed.		M. Binderberger, Ed.
	Cisco Systems		Cisco Systems
	J. Haas, Ed.		J. Haas, Ed.
	Juniper Networks		Juniper Networks
	November 11, 2013		November 30, 2013
	Bidirectional Forwarding Detection (BFD) on Link Aggregation Group (LAG)		Bidirectional Forwarding Detection (BFD) on Link Aggregation Group (LAG)
	Interfaces		Interfaces
	draft-ietf-bfd-on-lags-02		draft-ietf-bfd-on-lags-03
	Abstract		Abstract
	This document proposes a mechanism to run BFD on Link Aggregation		This document defines a mechanism to run BFD on Link Aggregation
	Group (LAG) interfaces. It does so by running an independent		Group (LAG) interfaces. It does so by running an independent
	Asynchronous mode BFD session on every LAG member link.		Asynchronous mode BFD session on every LAG member link.
	This mechanism allows the verification of member link continuity,		This mechanism allows the verification of member link continuity,
	either in combination with, or in absence of, LACP. It provides a		either in combination with, or in absence of, Link Aggregation
	shorter detection time than what LACP offers. The continuity check		Control Protocol (LACP). It provides a shorter detection time than
	can also cover elements of layer 3 bidirectional forwarding.		what LACP offers. The continuity check can also cover elements of
			layer 3 bidirectional forwarding.
	This mechanism utilizes a well-known UDP port distinct from that of		This mechanism utilizes a well-known UDP port distinct from that of
	single-hop BFD over IP. This new UDP port removes the ambiguity of		single-hop BFD over IP. This new UDP port removes the ambiguity of
	BFD over LAG packets from BFD over single-hop IP.		BFD over LAG packets from BFD over single-hop IP.
	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
	document are to be interpreted as described in RFC 2119 [RFC2119].		document are to be interpreted as described in RFC 2119 [RFC2119].
	skipping to change at page 2, line 8		skipping to change at page 2, line 10
	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 May 15, 2014.		This Internet-Draft will expire on June 3, 2014.
	Copyright Notice		Copyright Notice
	Copyright (c) 2013 IETF Trust and the persons identified as the		Copyright (c) 2013 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 4, line 44		skipping to change at page 4, line 44
	The approach taken in this document is to run a Asynchronous mode BFD		The approach taken in this document is to run a Asynchronous mode BFD
	session over each LAG member link and make BFD control whether the		session over each LAG member link and make BFD control whether the
	LAG member link should be part of the L2 Loadbalance table of the LAG		LAG member link should be part of the L2 Loadbalance table of the LAG
	interface in the presence or the absence of LACP.		interface in the presence or the absence of LACP.
	This document describes how to establish an Asynchronous mode BFD		This document describes how to establish an Asynchronous mode BFD
	session per physical LAG member link of the LAG interface.		session per physical LAG member link of the LAG interface.
	While there are native Ethernet mechanisms to detect failures		While there are native Ethernet mechanisms to detect failures
	(802.1ax, .3ah) that could be used for LAG, the solution proposed in		(802.1ax, .3ah) that could be used for LAG, the solution defined in
	this document enables operators who have already deployed BFD over		this document enables operators who have already deployed BFD over
	different technologies (e.g. IP, MPLS) to use a common failure		different technologies (e.g. IP, MPLS) to use a common failure
	detection mechanism.		detection mechanism.
	2. BFD on LAG member links		2. BFD on LAG member links
	The mechanism proposed for a fast detection of LAG member link		The mechanism defined for a fast detection of LAG member link failure
	failure is to run Asynchronous mode BFD sessions on every LAG member		is to run Asynchronous mode BFD sessions on every LAG member link.
	link. We call these per LAG member link BFD sessions "micro BFD		We call these per LAG member link BFD sessions "micro BFD sessions"
	sessions" in the remainder of this document.		in the remainder of this document.
	2.1. Micro BFD session address family		2.1. Micro BFD session address family
	Member link micro BFD sessions, when using IP/UDP encapsulation, can		Member link micro BFD sessions, when using IP/UDP encapsulation, can
	use IPv4 or IPv6 addresses. Two micro sessions MAY exist per member		use IPv4 or IPv6 addresses. Two micro sessions MAY exist per member
	link, one IPv4, another IPv6. When an address family is used on one		link, one IPv4, another IPv6. When an address family is used on one
	member link then it MUST be used on all member links of the		member link then it MUST be used on all member links of the
	particular LAG.		particular LAG.
	2.2. Micro BFD session negotiation		2.2. Micro BFD session negotiation
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	tagged micro BFD packets.		tagged micro BFD packets.
	3. Interaction between LAG and BFD		3. Interaction between LAG and BFD
	The micro BFD sessions for a particular LAG member link MUST be		The micro BFD sessions for a particular LAG member link MUST be
	requested when a member link state is either Distributing or Standby.		requested when a member link state is either Distributing or Standby.
	The sessions MUST be deleted when the member link is neither in		The sessions MUST be deleted when the member link is neither in
	Distributing nor in Standby state anymore.		Distributing nor in Standby state anymore.
	BFD is used to control if the load balance algorithm is able to		BFD is used to control if the load balance algorithm is able to
	select a particular LAG member link. In other words, even when LACP		select a particular LAG member link. In other words, even when Link
	is used and considers the member link to be ready to forward traffic,		Aggregation Control Protocol (LACP) is used and considers the member
	the member link MUST NOT be used by the load balancer until all the		link to be ready to forward traffic, the member link MUST NOT be used
	micro BFD sessions of the particular member link are in Up state.		by the load balancer until all the micro BFD sessions of the
			particular member link are in Up state.
	In case an implementation has separate load balance tables for IPv4		In case an implementation has separate load balance tables for IPv4
	and IPv6 and if both an IPv4 and IPv6 micro session exist for a		and IPv6 and if both an IPv4 and IPv6 micro session exist for a
	member link then an implementation MAY enable the member link in the		member link then an implementation MAY enable the member link in the
	load balance algorithm based on the BFD session with a matching		load balance algorithm based on the BFD session with a matching
	address family alone.		address family alone.
	An exception is the BFD packet itself. Implementations MAY receive		An exception is the BFD packet itself. Implementations MAY receive
	and transmit BFD packets via the Aggregator's MAC service interface		and transmit BFD packets via the Aggregator's MAC service interface
	independent of the session state.		independent of the session state.
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	6. Security Consideration		6. Security Consideration
	This document does not introduce any additional security issues and		This document does not introduce any additional security issues and
	the security mechanisms defined in [RFC5880] apply in this document.		the security mechanisms defined in [RFC5880] apply in this document.
	7. IANA Considerations		7. IANA Considerations
	IANA assigned a dedicated MAC address 01-00-5E-90-00-01 (see		IANA assigned a dedicated MAC address 01-00-5E-90-00-01 (see
	[RFC7042]) as well as UDP port 6784 for UDP encapsulated micro BFD		[RFC7042]) as well as UDP port 6784 for Bidirectional Forwarding
	sessions.		Detection (BFD) on Link Aggregation Group (LAG) Interfaces.
	8. Acknowledgements		8. Acknowledgements
	We would like to thank Dave Katz, Alexander Vainshtein, Greg Mirsky		We would like to thank Dave Katz, Alexander Vainshtein, Greg Mirsky
	and Jeff Tantsura for their comments.		and Jeff Tantsura for their comments.
	The initial event to start the current discussion was the		The initial event to start the current discussion was the
	distribution of draft-chen-bfd-interface-00.		distribution of draft-chen-bfd-interface-00.
	9. Contributing authors		9. Contributing authors
	skipping to change at page 10, line 15		skipping to change at page 10, line 15
	service.		service.
	If the BFD over LAG feature was deprovisioned on an aggregate link		If the BFD over LAG feature was deprovisioned on an aggregate link
	member while the associated micro BFD session was in Up state, BFD		member while the associated micro BFD session was in Up state, BFD
	SHOULD transition its state to AdminDown and SHOULD attempt to		SHOULD transition its state to AdminDown and SHOULD attempt to
	communicate this state change to the peer.		communicate this state change to the peer.
	If the local or the remote state of a micro BFD session is AdminDown		If the local or the remote state of a micro BFD session is AdminDown
	the system SHOULD NOT indicate a connectivity failure to any client		the system SHOULD NOT indicate a connectivity failure to any client
	and SHOULD NOT remove the particular LAG member link from forwarding.		and SHOULD NOT remove the particular LAG member link from forwarding.
	This behaviour is independent from the use of LACP for the LAG.		This behaviour is independent from the use of Link Aggregation
			Control Protocol (LACP) for the LAG.
	When traffic is forwarded across a link while the corresponding micro		When traffic is forwarded across a link while the corresponding micro
	BFD session is not in Up state an implementation MAY use a		BFD session is not in Up state an implementation MAY use a
	configurable timeout value after which the BFD session must have		configurable timeout value after which the BFD session must have
	reached Up state or otherwise the link is taken out of forwarding.		reached Up state or otherwise the link is taken out of forwarding.
	When such timeout values exist then the configuration MUST allow to		When such timeout values exist then the configuration MUST allow to
	turn off the timeout function.		turn off the timeout function.
	The configurable timeout value shall ensure that a LAG is not		The configurable timeout value shall ensure that a LAG is not
End of changes. 11 change blocks.
	20 lines changed or deleted		23 lines changed or added
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