< draft-ietf-bfd-vxlan-09.txt		draft-ietf-bfd-vxlan-10.txt >
	BFD S. Pallagatti, Ed.		BFD S. Pallagatti, Ed.
	Internet-Draft VMware		Internet-Draft VMware
	Intended status: Standards Track S. Paragiri		Intended status: Standards Track S. Paragiri
	Expires: June 1, 2020 Individual Contributor		Expires: June 27, 2020 Individual Contributor
	V. Govindan		V. Govindan
	M. Mudigonda		M. Mudigonda
	Cisco		Cisco
	G. Mirsky		G. Mirsky
	ZTE Corp.		ZTE Corp.
	November 29, 2019		December 25, 2019
	BFD for VXLAN		BFD for VXLAN
	draft-ietf-bfd-vxlan-09		draft-ietf-bfd-vxlan-10
	Abstract		Abstract
	This document describes the use of the Bidirectional Forwarding		This document describes the use of the Bidirectional Forwarding
	Detection (BFD) protocol in point-to-point Virtual eXtensible Local		Detection (BFD) protocol in point-to-point Virtual eXtensible Local
	Area Network (VXLAN) tunnels forming up an overlay network.		Area Network (VXLAN) tunnels used to form an overlay network.
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This Internet-Draft is submitted in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
	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 https://datatracker.ietf.org/drafts/current/.		Drafts is at https://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 June 1, 2020.		This Internet-Draft will expire on June 27, 2020.
	Copyright Notice		Copyright Notice
	Copyright (c) 2019 IETF Trust and the persons identified as the		Copyright (c) 2019 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
	(https://trustee.ietf.org/license-info) in effect on the date of		(https://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 16 ¶		skipping to change at page 2, line 16 ¶
	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 . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	2. Conventions used in this document . . . . . . . . . . . . . . 3		2. Conventions used in this document . . . . . . . . . . . . . . 3
	2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3		2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
	2.2. Requirements Language . . . . . . . . . . . . . . . . . . 3		2.2. Requirements Language . . . . . . . . . . . . . . . . . . 3
	3. Deployment . . . . . . . . . . . . . . . . . . . . . . . . . 4		3. Deployment . . . . . . . . . . . . . . . . . . . . . . . . . 4
	4. BFD Packet Transmission over VXLAN Tunnel . . . . . . . . . . 5		4. BFD Packet Transmission over VXLAN Tunnel . . . . . . . . . . 6
	5. Reception of BFD Packet from VXLAN Tunnel . . . . . . . . . . 7		5. Reception of BFD Packet from VXLAN Tunnel . . . . . . . . . . 8
	5.1. Demultiplexing of the BFD Packet . . . . . . . . . . . . 8		5.1. Demultiplexing of the BFD Packet . . . . . . . . . . . . 9
	6. Use of the Specific VNI . . . . . . . . . . . . . . . . . . . 8		6. Use of the Specific VNI . . . . . . . . . . . . . . . . . . . 9
	7. Echo BFD . . . . . . . . . . . . . . . . . . . . . . . . . . 8		7. Echo BFD . . . . . . . . . . . . . . . . . . . . . . . . . . 9
	8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8		8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
	9. Security Considerations . . . . . . . . . . . . . . . . . . . 8		9. Security Considerations . . . . . . . . . . . . . . . . . . . 9
	10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 9		10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 10
	11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9		11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10
	12. References . . . . . . . . . . . . . . . . . . . . . . . . . 9		12. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
	12.1. Normative References . . . . . . . . . . . . . . . . . . 9		12.1. Normative References . . . . . . . . . . . . . . . . . . 10
	12.2. Informational References . . . . . . . . . . . . . . . . 10		12.2. Informational References . . . . . . . . . . . . . . . . 11
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
	1. Introduction		1. Introduction
	"Virtual eXtensible Local Area Network" (VXLAN) [RFC7348] provides an		"Virtual eXtensible Local Area Network" (VXLAN) [RFC7348] provides an
	encapsulation scheme that allows building an overlay network by		encapsulation scheme that allows building an overlay network by
	decoupling the address space of the attached virtual hosts from that		decoupling the address space of the attached virtual hosts from that
	of the network.		of the network.
	One use of VXLAN is in data centers interconnecting virtual machines		One use of VXLAN is in data centers interconnecting virtual machines
	(VMs) of a tenant. VXLAN addresses requirements of the Layer 2 and		(VMs) of a tenant. VXLAN addresses requirements of the Layer 2 and
	skipping to change at page 3, line 8 ¶		skipping to change at page 3, line 8 ¶
	hypervisors. However, the concepts are equally applicable to non-		hypervisors. However, the concepts are equally applicable to non-
	virtualized hosts attached to VTEPs in switches.		virtualized hosts attached to VTEPs in switches.
	In the absence of a router in the overlay, a VM can communicate with		In the absence of a router in the overlay, a VM can communicate with
	another VM only if they are on the same VXLAN segment. VMs are		another VM only if they are on the same VXLAN segment. VMs are
	unaware of VXLAN tunnels as a VXLAN tunnel is terminated on a VTEP.		unaware of VXLAN tunnels as a VXLAN tunnel is terminated on a VTEP.
	VTEPs are responsible for encapsulating and decapsulating frames		VTEPs are responsible for encapsulating and decapsulating frames
	exchanged among VMs.		exchanged among VMs.
	Ability to monitor path continuity, i.e., perform proactive		The ability to monitor path continuity, i.e., perform proactive
	continuity check (CC) for point-to-point (p2p) VXLAN tunnels, is		continuity check (CC) for point-to-point (p2p) VXLAN tunnels, is
	important. The asynchronous mode of BFD, as defined in [RFC5880], is		important. The asynchronous mode of BFD, as defined in [RFC5880], is
	used to monitor a p2p VXLAN tunnel.		used to monitor a p2p VXLAN tunnel.
	In the case where a Multicast Service Node (MSN) (as described in		In the case where a Multicast Service Node (MSN) (as described in
	Section 3.3 of [RFC8293]) resides behind a Network Virtualization		Section 3.3 of [RFC8293]) resides behind a Network Virtualization
	Endpoint (NVE), the mechanisms described in this document apply and		Endpoint (NVE), the mechanisms described in this document apply and
	can, therefore, be used to test the connectivity from the source NVE		can, therefore, be used to test the connectivity from the source NVE
	to the MSN.		to the MSN.
	skipping to change at page 4, line 14 ¶		skipping to change at page 4, line 14 ¶
	14 [RFC2119] [RFC8174] when, and only when, they appear in all		14 [RFC2119] [RFC8174] when, and only when, they appear in all
	capitals, as shown here.		capitals, as shown here.
	3. Deployment		3. Deployment
	Figure 1 illustrates the scenario with two servers, each of them		Figure 1 illustrates the scenario with two servers, each of them
	hosting two VMs. The servers host VTEPs that terminate two VXLAN		hosting two VMs. The servers host VTEPs that terminate two VXLAN
	tunnels with VXLAN Network Identifier (VNI) number 100 and 200		tunnels with VXLAN Network Identifier (VNI) number 100 and 200
	respectively. Separate BFD sessions can be established between the		respectively. Separate BFD sessions can be established between the
	VTEPs (IP1 and IP2) for monitoring each of the VXLAN tunnels (VNI 100		VTEPs (IP1 and IP2) for monitoring each of the VXLAN tunnels (VNI 100
	and 200). An implementation that supports this specification MUST be		and 200). Using a BFD session to monitor a set of VXLAN VNIs between
	able to control the number of BFD sessions that can be created		the same pair of VTEPs might help to detect and localize problems
	between the same pair of VTEPs. BFD packets intended for a VTEP MUST		caused by misconfiguration. An implementation that supports this
	NOT be forwarded to a VM as a VM may drop BFD packets leading to a		specification MUST be able to control the number of BFD sessions that
	false negative. This method is applicable whether the VTEP is a		can be created between the same pair of VTEPs. BFD packets intended
	virtual or physical device.		for a VTEP MUST NOT be forwarded to a VM, as a VM may drop BFD
			packets, leading to a false negative. This method is applicable
			whether the VTEP is a virtual or physical device.
	+------------+-------------+		+------------+-------------+
	| Server 1 |		| Server 1 |
	| +----+----+ +----+----+ |		| +----+----+ +----+----+ |
	| |VM1-1 | |VM1-2 | |		| |VM1-1 | |VM1-2 | |
	| |VNI 100 | |VNI 200 | |		| |VNI 100 | |VNI 200 | |
	| | | | | |		| | | | | |
	| +---------+ +---------+ |		| +---------+ +---------+ |
	| VTEP (IP1) |		| VTEP (IP1) |
	+--------------------------+		+--------------------------+
	skipping to change at page 5, line 6 ¶		skipping to change at page 5, line 35 ¶
	| |VM2-1 | |VM2-2 | |		| |VM2-1 | |VM2-2 | |
	| |VNI 100 | |VNI 200 | |		| |VNI 100 | |VNI 200 | |
	| | | | | |		| | | | | |
	| +---------+ +---------+ |		| +---------+ +---------+ |
	| Server 2 |		| Server 2 |
	+--------------------------+		+--------------------------+
	Figure 1: Reference VXLAN Domain		Figure 1: Reference VXLAN Domain
	At the same time, a service layer BFD session may be used between the		At the same time, a service layer BFD session may be used between the
	tenants of VTEPs IP1 and IP2 to provide end-to-end fault management.		tenants of VTEPs IP1 and IP2 to provide end-to-end fault management
	In such case, for VTEPs BFD Control packets of that session are		(this use case is outside the scope of this document). In such case,
	indistinguishable from data packets.		for VTEPs BFD Control packets of that session are indistinguishable
			from data packets.
	As per Section 4, the inner destination IP address SHOULD be set to		For BFD Control packets encapsulated in VXLAN (Figure 2), the inner
	one of the loopback addresses (127/8 range for IPv4 and		destination IP address SHOULD be set to one of the loopback addresses
	0:0:0:0:0:FFFF:7F00:0/104 range for IPv6). There could be a firewall		from 127/8 range for IPv4 or to one of IPv4-mapped IPv4 loopback
	configured on VTEP to block loopback addresses if set as the		addresses from ::ffff:127.0.0.0/104 range for IPv6. There could be a
			firewall configured on VTEP to block loopback addresses if set as the
	destination IP in the inner IP header. It is RECOMMENDED to allow		destination IP in the inner IP header. It is RECOMMENDED to allow
	addresses from the loopback range through a firewall only if it is		addresses from the loopback range through a firewall only if they are
	used as the destination IP address in the inner IP header, and the		used as the destination IP addresses in the inner IP header and the
	destination UDP port is set to 3784 [RFC5881].		destination UDP port is set to 3784 [RFC5881].
	4. BFD Packet Transmission over VXLAN Tunnel		4. BFD Packet Transmission over VXLAN Tunnel
	BFD packet MUST be encapsulated and sent to a remote VTEP as		BFD packets MUST be encapsulated and sent to a remote VTEPs as
	explained in this section. Implementations SHOULD ensure that the		explained in this section. Implementations SHOULD ensure that the
	BFD packets follow the same lookup path as VXLAN data packets within		BFD packets follow the same forwarding path as VXLAN data packets
	the sender system.		within the sender system.
	BFD packets are encapsulated in VXLAN as described below. The VXLAN		BFD packets are encapsulated in VXLAN as described below. The VXLAN
	packet format is defined in Section 5 of [RFC7348]. The Outer IP/UDP		packet format is defined in Section 5 of [RFC7348]. The Outer IP/UDP
	and VXLAN headers MUST be encoded by the sender as defined in		and VXLAN headers MUST be encoded by the sender as defined in
	[RFC7348].		[RFC7348].
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| |		| |
	skipping to change at page 6, line 40 ¶		skipping to change at page 7, line 40 ¶
	| |		| |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| |		| |
	~ Inner UDP Header ~		~ Inner UDP Header ~
	| |		| |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| |		| |
	~ BFD Control Packet ~		~ BFD Control Packet ~
	| |		| |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| FCS |		| Outer FCS |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Figure 2: VXLAN Encapsulation of BFD Control Packet		Figure 2: VXLAN Encapsulation of BFD Control Packet
	The BFD packet MUST be carried inside the inner Ethernet frame of the		The BFD packet MUST be carried inside the inner Ethernet frame of the
	VXLAN packet. The choice of Destination MAC and Destination IP		VXLAN packet. The choice of Destination MAC and Destination IP
	addresses for the inner Ethernet frame MUST ensure that the BFD		addresses for the inner Ethernet frame MUST ensure that the BFD
	Control packet is not forwarded to a tenant but is processed locally		Control packet is not forwarded to a tenant but is processed locally
	at the remote VTEP. The inner Ethernet frame carrying the BFD		at the remote VTEP. The inner Ethernet frame carrying the BFD
	Control packet- has the following format:		Control packet- has the following format:
	Ethernet Header:		Ethernet Header:
	Destination MAC: This MUST NOT be of one of tenant's MAC		Destination MAC: This MUST NOT be of one of tenant's MAC
	addresses. The destination MAC address MAY be the address		addresses. The destination MAC address MAY be the address
	associated with the destination VTEP. The MAC address MAY be		associated with the destination VTEP. The MAC address may be
	configured, or it MAY be learned via a control plane protocol.		either configured or learned via a control plane protocol. The
	The details of how the MAC address is obtained are outside the		details of how the MAC address is obtained are outside the
	scope of this document.		scope of this document.
	Source MAC: MAC address associated with the originating VTEP		Source MAC: MAC address associated with the originating VTEP
	IP header:		IP header:
	Destination IP: IP address MUST NOT be of one of tenant's IP		Destination IP: IP address MUST NOT be of one of tenant's IP
	addresses. The IP address SHOULD be selected from the range		addresses. The IP address SHOULD be selected from the range
	127/8 for IPv4, for IPv6 - from the range		127/8 for IPv4, for IPv6 - from the range ::ffff:127.0.0.0/104.
	0:0:0:0:0:FFFF:7F00:0/104. Alternatively, the destination IP		Alternatively, the destination IP address MAY be set to VTEP's
	address MAY be set to VTEP's IP address.		IP address.
	Source IP: IP address of the originating VTEP.		Source IP: IP address of the originating VTEP.
	TTL or Hop Limit: MUST be set to 1 to ensure that the BFD		TTL or Hop Limit: MUST be set to 1 to ensure that the BFD
	packet is not routed within the Layer 3 underlay network. This		packet is not routed within the Layer 3 underlay network. This
	addresses the scenario when the inner IP destination address is		addresses the scenario when the inner IP destination address is
	of VXLAN gateway and there is a router in underlay which		of the VXLAN gateway and there is a router in the underlay
	removes the VXLAN header, then it is possible to route the		which removes the VXLAN header, then it is possible to route
	packet as VXLAN gateway address is routable address.		the packet as VXLAN gateway address is routable address.
	The fields of the UDP header and the BFD Control packet are		The fields of the UDP header and the BFD Control packet are
	encoded as specified in [RFC5881].		encoded as specified in [RFC5881].
	5. Reception of BFD Packet from VXLAN Tunnel		5. Reception of BFD Packet from VXLAN Tunnel
	Once a packet is received, VTEP MUST validate the packet. If the		Once a packet is received, the VTEP MUST validate the packet. If the
	Destination MAC of the inner Ethernet frame matches one of the MAC		Destination MAC of the inner Ethernet frame matches one of the MAC
	addresses associated with the VTEP the packet MUST be processed		addresses associated with the VTEP the packet MUST be processed
	further. If the Destination MAC of the inner Ethernet frame doesn't		further. If the Destination MAC of the inner Ethernet frame doesn't
	match any of VTEP's MAC addresses, then the processing of the		match any of VTEP's MAC addresses, then the processing of the
	received VXLAN packet MUST follow the procedures described in		received VXLAN packet MUST follow the procedures described in
	Section 4.1 [RFC7348]. If the BFD session is using the Management		Section 4.1 of [RFC7348]. If the BFD session is using the Management
	VNI (Section 6), BFD Control packets with unknown MAC address MUST		VNI (Section 6), BFD Control packets with unknown MAC address MUST
	NOT be forwarded to VMs.		NOT be forwarded to VMs.
	The UDP destination port and the TTL of the inner IP packet MUST be		The UDP destination port and the TTL or Hop Limit of the inner IP
	validated to determine if the received packet can be processed by		packet MUST be validated to determine if the received packet can be
	BFD.		processed by BFD.
	5.1. Demultiplexing of the BFD Packet		5.1. Demultiplexing of the BFD Packet
	Demultiplexing of IP BFD packet has been defined in Section 3 of		Demultiplexing of IP BFD packet has been defined in Section 3 of
	[RFC5881]. Since multiple BFD sessions may be running between two		[RFC5881]. Since multiple BFD sessions may be running between two
	VTEPs, there needs to be a mechanism for demultiplexing received BFD		VTEPs, there needs to be a mechanism for demultiplexing received BFD
	packets to the proper session. For demultiplexing packets with Your		packets to the proper session. For demultiplexing packets with Your
	Discriminator equal to 0, a BFD session MUST be identified using the		Discriminator equal to 0, a BFD session MUST be identified using the
	logical link over which the BFD Control packet is received. In the		logical link over which the BFD Control packet is received. In the
	case of VXLAN, the VNI number identifies that logical link. If BFD		case of VXLAN, the VNI number identifies that logical link. If BFD
	packet is received with non-zero Your Discriminator, then BFD session		packet is received with non-zero Your Discriminator, then the BFD
	MUST be demultiplexed only with Your Discriminator as the key.		session MUST be demultiplexed only with Your Discriminator as the
			key.
	6. Use of the Specific VNI		6. Use of the Specific VNI
	In most cases, a single BFD session is sufficient for the given VTEP		In most cases, a single BFD session is sufficient for the given VTEP
	to monitor the reachability of a remote VTEP, regardless of the		to monitor the reachability of a remote VTEP, regardless of the
	number of VNIs. When the single BFD session is used to monitor the		number of VNIs. When the single BFD session is used to monitor the
	reachability of the remote VTEP, an implementation SHOULD choose any		reachability of the remote VTEP, an implementation SHOULD choose any
	of the VNIs. An implementation MAY support the use of the Management		of the VNIs. An implementation MAY support the use of the Management
	VNI as control and management channel between VTEPs. The selection		VNI as control and management channel between VTEPs. The selection
	of the VNI number of the Management VNI MUST be controlled through		of the VNI number of the Management VNI MUST be controlled through
	skipping to change at page 8, line 42 ¶		skipping to change at page 9, line 43 ¶
	Support for echo BFD is outside the scope of this document.		Support for echo BFD is outside the scope of this document.
	8. IANA Considerations		8. IANA Considerations
	This specification has no IANA action requested. This section may be		This specification has no IANA action requested. This section may be
	deleted before the publication.		deleted before the publication.
	9. Security Considerations		9. Security Considerations
	The document requires setting the inner IP TTL to 1, which could be		The document requires setting the inner IP TTL or Hop Limit to 1,
	used as a DDoS attack vector. Thus the implementation MUST have		which could be used as a DDoS attack vector. Thus the implementation
	throttling in place to control the rate of BFD Control packets sent		MUST have throttling in place to control the rate of BFD Control
	to the control plane. On the other hand, over-aggressive throttling		packets sent to the control plane. On the other hand, over-
	of BFD Control packets may become the cause of the inability to form		aggressive throttling of BFD Control packets may become the cause of
	and maintain BFD session at scale. Hence, throttling of BFD Control		the inability to form and maintain BFD session at scale. Hence,
	packets SHOULD be adjusted to permit BFD to work according to its		throttling of BFD Control packets SHOULD be adjusted to permit BFD to
	procedures.		work according to its procedures.
	This document recommends using an address from the Internal host		This document recommends using an address from the Internal host
	loopback addresses (127/8 range for IPv4 and		loopback addresses 127/8 range for IPv4 or an IP4-mapped IPv4
	0:0:0:0:0:FFFF:7F00:0/104 range for IPv6) as the destination IP		loopback address from ::ffff:127.0.0.0/104 range for IPv6 as the
	address in the inner IP header. Using such address prevents the		destination IP address in the inner IP header. Using such an address
	forwarding of the encapsulated BFD control message by a transient		prevents the forwarding of the encapsulated BFD control message by a
	node in case the VXLAN tunnel is broken as according to [RFC1812]:		transient node in case the VXLAN tunnel is broken as according to
			[RFC1812]:
	A router SHOULD NOT forward, except over a loopback interface, any		A router SHOULD NOT forward, except over a loopback interface, any
	packet that has a destination address on network 127. A router		packet that has a destination address on network 127. A router
	MAY have a switch that allows the network manager to disable these		MAY have a switch that allows the network manager to disable these
	checks. If such a switch is provided, it MUST default to		checks. If such a switch is provided, it MUST default to
	performing the checks.		performing the checks.
	If the implementation supports establishing multiple BFD sessions		If the implementation supports establishing multiple BFD sessions
	between the same pair of VTEPs, there SHOULD be a mechanism to		between the same pair of VTEPs, there SHOULD be a mechanism to
	control the maximum number of such sessions that can be active at the		control the maximum number of such sessions that can be active at the
	same time.		same time.
	Other than inner IP TTL set to 1 and limit the number of BFD sessions		Other than setting the value of inner IP TTL or Hop Limit to 1 and
	between the same pair of VTEPs, this specification does not raise any		limit the number of BFD sessions between the same pair of VTEPs, this
	additional security issues beyond those of the specifications		specification does not raise any additional security issues beyond
	referred to in the list of normative references.		those discussed in [RFC5880], [RFC5881], and [RFC7348].
	10. Contributors		10. Contributors
	Reshad Rahman		Reshad Rahman
	rrahman@cisco.com		rrahman@cisco.com
	Cisco		Cisco
	11. Acknowledgments		11. Acknowledgments
	Authors would like to thank Jeff Haas of Juniper Networks for his		Authors would like to thank Jeff Haas of Juniper Networks for his
End of changes. 24 change blocks.
	71 lines changed or deleted		77 lines changed or added
This html diff was produced by rfcdiff 1.47. The latest version is available from http://tools.ietf.org/tools/rfcdiff/