< draft-spallagatti-bfd-vxlan-05.txt   draft-spallagatti-bfd-vxlan-06.txt >
Internet Engineering Task Force S. Pallagatti, Ed. Internet Engineering Task Force S. Pallagatti, Ed.
Internet-Draft Independent Contributor Internet-Draft Independent Contributor
Intended status: Standards Track S. Paragiri Intended status: Standards Track S. Paragiri
Expires: October 21, 2017 Juniper Networks Expires: April 16, 2018 Juniper Networks
V. Govindan V. Govindan
M. Mudigonda M. Mudigonda
Cisco Cisco
G. Mirsky G. Mirsky
ZTE Corp. ZTE Corp.
April 19, 2017 October 13, 2017
BFD for VXLAN BFD for VXLAN
draft-spallagatti-bfd-vxlan-05 draft-spallagatti-bfd-vxlan-06
Abstract Abstract
This document describes use of Bidirectional Forwarding Detection This document describes use of Bidirectional Forwarding Detection
(BFD) protocol in Virtual eXtensible Local Area Network (VXLAN) (BFD) protocol in Virtual eXtensible Local Area Network (VXLAN)
overlay network. 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
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This Internet-Draft will expire on October 21, 2017. This Internet-Draft will expire on April 16, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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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. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Deployment . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Deployment . . . . . . . . . . . . . . . . . . . . . . . . . 4
5. BFD Packet Transmission over VXLAN Tunnel . . . . . . . . . . 6 5. BFD Packet Transmission over VXLAN Tunnel . . . . . . . . . . 5
5.1. BFD Packet Encapsulation in VXLAN . . . . . . . . . . . . 6 5.1. BFD Packet Encapsulation in VXLAN . . . . . . . . . . . . 6
6. Reception of BFD packet from VXLAN Tunnel . . . . . . . . . . 6 6. Reception of BFD packet from VXLAN Tunnel . . . . . . . . . . 7
6.1. Demultiplexing of the BFD packet . . . . . . . . . . . . 7 6.1. Demultiplexing of the BFD packet . . . . . . . . . . . . 8
7. Use of reserved VNI . . . . . . . . . . . . . . . . . . . . . 7 7. Use of reserved VNI . . . . . . . . . . . . . . . . . . . . . 8
8. Echo BFD . . . . . . . . . . . . . . . . . . . . . . . . . . 7 8. Echo BFD . . . . . . . . . . . . . . . . . . . . . . . . . . 8
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
10. Security Considerations . . . . . . . . . . . . . . . . . . . 7 10. Security Considerations . . . . . . . . . . . . . . . . . . . 8
11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 8 11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 8
12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 8 12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9
13. Normative References . . . . . . . . . . . . . . . . . . . . 8 13. Normative References . . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction 1. Introduction
"Virtual eXtensible Local Area Network (VXLAN)" has been described in "Virtual eXtensible Local Area Network (VXLAN)" has been described in
[RFC7348]. VXLAN provides an encapsulation scheme that allows [RFC7348]. VXLAN provides an encapsulation scheme that allows
virtual machines (VMs) to communicate in a data center network. virtual machines (VMs) to communicate in a data center network.
VXLAN is typically deployed in data centers interconnecting VXLAN is typically deployed in data centers interconnecting
virtualized hosts, which may be spread across multiple racks. The virtualized hosts, which may be spread across multiple racks. The
individual racks may be part of a different Layer 3 network or they individual racks may be part of a different Layer 3 network or they
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terminated on VXLAN Tunnel End Point (VTEP) (hypervisor/TOR). VTEPs terminated on VXLAN Tunnel End Point (VTEP) (hypervisor/TOR). VTEPs
(hypervisor/TOR) are responsible for encapsulating and decapsulating (hypervisor/TOR) are responsible for encapsulating and decapsulating
frames exchanged among VMs. frames exchanged among VMs.
Since underlay is a L3 network, ability to monitor path continuity, Since underlay is a L3 network, ability to monitor path continuity,
i.e. perform proactive continuity check (CC) for these tunnels is i.e. perform proactive continuity check (CC) for these tunnels is
important. Asynchronous mode of BFD, as defined in [RFC5880], can be important. Asynchronous mode of BFD, as defined in [RFC5880], can be
used to monitor a VXLAN tunnel. Use of [I-D.ietf-bfd-multipoint] is used to monitor a VXLAN tunnel. Use of [I-D.ietf-bfd-multipoint] is
for future study. for future study.
This draft addresses requirements outlined in Also BFD in VXLAN can be used to monitor special service nodes that
[I-D.ashwood-nvo3-operational-requirement]. Specifically with are designated to properly handle Layer 2 broadcast, unknown unicast,
reference to the OAM model to Figure 3 of and multicast traffic. Such nodes, often referred "replicators", are
[I-D.ashwood-nvo3-operational-requirement], this draft outlines usually virtual VTEPs can be monitored by physical VTEPs in order to
proposal to implement the OAM mechanism between the Network minimize BUM traffic directed to unavialable replicator.
Virtualization Edges (NVEs) using BFD.
This document describes use of Bidirectional Forwarding Detection
(BFD) protocol VXLAN to enable continuity monitoring between Network
Virtualization Edges (NVEs) and/or availability of a replicator
service node using BFD.
2. Conventions used in this document 2. Conventions used in this document
2.1. Terminology 2.1. Terminology
BFD - Bidirectional Forwarding Detection BFD - Bidirectional Forwarding Detection
CC - Continuity Check CC - Continuity Check
NVE - Network Virtualization Edge NVE - Network Virtualization Edge
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VM - Virtual Machine VM - Virtual Machine
VTEP - VXLAN Tunnel End Point VTEP - VXLAN Tunnel End Point
VXLAN - Virtual eXtensible Local Area Network VXLAN - Virtual eXtensible Local Area Network
2.2. Requirements Language 2.2. 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", "NOT RECOMMENDED", "MAY", and
document are to be interpreted as described in RFC 2119 [RFC2119]. "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. Use cases 3. Use cases
Main use case of BFD for VXLAN is for continuity check of a tunnel. Main use case of BFD for VXLAN is for continuity check of a tunnel.
By exchanging BFD control packets between VTEPs an operator exercises By exchanging BFD control packets between VTEPs an operator exercises
the VXLAN path in both in underlay and overlay thus ensuring the the VXLAN path in both in underlay and overlay thus ensuring the
VXLAN path availability and VTEPs reachability. BFD failure VXLAN path availability and VTEPs reachability. BFD failure
detection can be used for maintenance. There are other use cases detection can be used for maintenance. There are other use cases
such as such as
Layer 2 VMs: Layer 2 VMs:
Most deployments will have VMs with only L2 capabilities that Most deployments will have VMs with only L2 capabilities that
may not support L3. BFD being a L3 protocol can be used as may not support L3. BFD being a L3 protocol can be used as
tunnel CC mechanism, where BFD will start and terminate at the tunnel CC mechanism, where BFD will start and terminate at the
NVEs, e.g. VTEPs. NVEs, e.g. VTEPs.
It is possible to aggregate the CC sessions for multiple It is possible to aggregate the CC sessions for multiple
tenants by running a BFD session between the VTEPs over VxLAN tenants by running a BFD session between the VTEPs over VxLAN
tunnel. In rest of this document terms NVE and VTEP are used tunnel. In rest of this document terms NVE and VTEP are used
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helps localize faults though requires additional consideration. helps localize faults though requires additional consideration.
Service node reachability: Service node reachability:
Service node is responsible for sending BUM traffic. In case Service node is responsible for sending BUM traffic. In case
of service node tunnel terminates at VTEP and it might not even of service node tunnel terminates at VTEP and it might not even
host VM. BFD session between TOR/hypervisor and service node host VM. BFD session between TOR/hypervisor and service node
can be used to monitor service node reachability. can be used to monitor service node reachability.
4. Deployment 4. Deployment
Figure 1 illustrates the scenario with two servers, each of them
hosting two VMs. These servers host VTEPs that terminate two VXLAN
tunnels with VNI number 100 and 200. Separate BFD sessions can be
established between the VTEPs (IP1 and IP2) for monitoring each of
the VXLAN tunnels (VNI 100 and 200). No BFD packets, intended to
Hypervisor VTEP, should be forwarded to a VM as VM may drop BFD
packets leading to false negative. This method is applicable whether
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 | |
| | | | | | | | | | | |
| +---------+ +---------+ | | +---------+ +---------+ |
| Hypervisor VTEP (IP1) | | Hypervisor VTEP (IP1) |
+--------------------------+ +--------------------------+
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+------------+-------------+ +------------+-------------+
| Hypervisor VTEP (IP2) | | Hypervisor VTEP (IP2) |
| +----+----+ +----+----+ | | +----+----+ +----+----+ |
| |VM2-1 | |VM2-2 | | | |VM2-1 | |VM2-2 | |
| |VNI 100 | |VNI 200 | | | |VNI 100 | |VNI 200 | |
| | | | | | | | | | | |
| +---------+ +---------+ | | +---------+ +---------+ |
| Server 2 | | Server 2 |
+--------------------------+ +--------------------------+
Figure 1 Figure 1: Reference VXLAN domain
Figure 1 illustrates the scenario with two servers, each of them
hosting two VMs. These servers host VTEPs that terminate two VXLAN
tunnels with VNI number 100 and 200. Separate BFD sessions can be
established between the VTEPs (IP1 and IP2) for monitoring each of
the VXLAN tunnels (VNI 100 and 200). No BFD packets, intended to
Hypervisor VTEP, should be forwarded to a VM as VM may drop BFD
packets leading to false negative. This method is applicable whether
VTEP is a virtual or physical device.
5. BFD Packet Transmission over VXLAN Tunnel 5. BFD Packet Transmission over VXLAN Tunnel
BFD packet MUST be encapsulated and sent to a remote VTEP as BFD packet MUST be encapsulated and sent to a remote VTEP as
explained in Section 5.1. Implementations SHOULD ensure that the BFD explained in Section 5.1. Implementations SHOULD ensure that the BFD
packets follow the same lookup path of VXLAN packets within the packets follow the same lookup path of VXLAN packets within the
sender system. sender system.
5.1. BFD Packet Encapsulation in VXLAN 5.1. BFD Packet Encapsulation in VXLAN
VXLAN packet format has been described in Section 5 of [RFC7348]. VXLAN packet format has been described in Section 5 of [RFC7348].
The Outer IP/UDP and VXLAN headers MUST be encoded by the sender as The Outer IP/UDP and VXLAN headers MUST be encoded by the sender as
per [RFC7348]. per [RFC7348].
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Outer Ethernet Header ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Outer IPvX Header ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Outer UDP Header ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ VXLAN Header ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Inner Ethernet Header ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Inner IPvX Header ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Inner UDP Header ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ BFD Control Message ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FCS |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: VXLAN Encapsulaion of BFD Control Message
The BFD packet MUST be carried inside the inner MAC frame of the The BFD packet MUST be carried inside the inner MAC frame of the
VXLAN packet. The inner MAC frame carrying the BFD payload has the VXLAN packet. The inner MAC frame carrying the BFD payload has the
following format: following format:
Ethernet Header: Ethernet Header:
Destination MAC: This MUST be a dedicated MAC (TBA) Section 9 Destination MAC: This MUST be a dedicated MAC (TBA) Section 9
or the MAC address of the destination VTEP. The details of how or the MAC address of the destination VTEP. The details of how
the MAC address of the destination VTEP is obtained are outside the MAC address of the destination VTEP is obtained are outside
the scope of this document. the scope of this document.
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the MAC-DA and VNI as key in the Virtual Forwarding Instance (VFI) the MAC-DA and VNI as key in the Virtual Forwarding Instance (VFI)
table of the originating/ terminating VTEP in order to exercise the table of the originating/ terminating VTEP in order to exercise the
VFI associated with the VNI. VFI associated with the VNI.
6.1. Demultiplexing of the BFD packet 6.1. 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. The procedure for demultiplexing packets to the proper session. The procedure for demultiplexing
packets with Your Discriminator = 0 is different from [RFC5880]. For packets with Your Discriminator equal to 0 is different from
such packets, the BFD session MUST be identified using the inner [RFC5880]. For such packets, the BFD session MUST be identified
headers, i.e. the source IP and the destination IP present in the IP using the inner headers, i.e. the source IP and the destination IP
header carried by the payload of the VXLAN encapsulated packet. The present in the IP header carried by the payload of the VXLAN
VNI of the packet SHOULD be used to derive interface related encapsulated packet. The VNI of the packet SHOULD be used to derive
information for demultiplexing the packet. If BFD packet is received interface related information for demultiplexing the packet. If BFD
with non-zero your discriminator then BFD session should be packet is received with non-zero Your Discriminator then BFD session
demultiplexed only with your discriminator as the key. MUST be demultiplexed only with Your Discriminator as the key.
7. Use of reserved VNI 7. Use of reserved VNI
BFD session MAY be established for the reserved VNI 0. One way to BFD session MAY be established for the reserved VNI 0. One way to
aggregate BFD sessions between VTEP's is to establish a BFD session aggregate BFD sessions between VTEP's is to establish a BFD session
with VNI 0. A VTEP MAY also use VNI 0 to establish a BFD session with VNI 0. A VTEP MAY also use VNI 0 to establish a BFD session
with a service node. with a service node.
8. Echo BFD 8. Echo BFD
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12. Acknowledgments 12. Acknowledgments
Authors would like to thank Jeff Hass of Juniper Networks for his Authors would like to thank Jeff Hass of Juniper Networks for his
reviews and feedback on this material. reviews and feedback on this material.
Authors would also like to thank Nobo Akiya, Marc Binderberger and Authors would also like to thank Nobo Akiya, Marc Binderberger and
Shahram Davari for the extensive review. Shahram Davari for the extensive review.
13. Normative References 13. Normative References
[I-D.ashwood-nvo3-operational-requirement]
Ashwood-Smith, P., Iyengar, R., Tsou, T., Sajassi, A.,
Boucadair, M., Jacquenet, C., and M. Daikoku, "NVO3
Operational Requirements", draft-ashwood-nvo3-operational-
requirement-03 (work in progress), July 2013.
[I-D.ietf-bfd-multipoint] [I-D.ietf-bfd-multipoint]
Katz, D., Ward, D., and J. Networks, "BFD for Multipoint Katz, D., Ward, D., and J. Networks, "BFD for Multipoint
Networks", draft-ietf-bfd-multipoint-09 (work in Networks", draft-ietf-bfd-multipoint-10 (work in
progress), October 2016. progress), April 2017.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010, (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,
<http://www.rfc-editor.org/info/rfc5880>. <https://www.rfc-editor.org/info/rfc5880>.
[RFC5881] Katz, D. and D. Ward, "Bidirectional Forwarding Detection [RFC5881] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD) for IPv4 and IPv6 (Single Hop)", RFC 5881, (BFD) for IPv4 and IPv6 (Single Hop)", RFC 5881,
DOI 10.17487/RFC5881, June 2010, DOI 10.17487/RFC5881, June 2010,
<http://www.rfc-editor.org/info/rfc5881>. <https://www.rfc-editor.org/info/rfc5881>.
[RFC7348] Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger, [RFC7348] Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger,
L., Sridhar, T., Bursell, M., and C. Wright, "Virtual L., Sridhar, T., Bursell, M., and C. Wright, "Virtual
eXtensible Local Area Network (VXLAN): A Framework for eXtensible Local Area Network (VXLAN): A Framework for
Overlaying Virtualized Layer 2 Networks over Layer 3 Overlaying Virtualized Layer 2 Networks over Layer 3
Networks", RFC 7348, DOI 10.17487/RFC7348, August 2014, Networks", RFC 7348, DOI 10.17487/RFC7348, August 2014,
<http://www.rfc-editor.org/info/rfc7348>. <https://www.rfc-editor.org/info/rfc7348>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
Authors' Addresses Authors' Addresses
Santosh Pallagatti (editor) Santosh Pallagatti (editor)
Independent Contributor Independent Contributor
Email: santosh.pallagatti@gmail.com Email: santosh.pallagatti@gmail.com
Sudarsan Paragiri Sudarsan Paragiri
Juniper Networks Juniper Networks
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