BFD for VXLAN
draft-spallagatti-bfd-vxlan-02
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Replaced".
|
|
|---|---|---|---|
| Authors | Santosh Pallagatti , sajibasil@gmail.com , Sudarsan Paragiri , Vengada Prasad Govindan , Mallik Mudigonda, Greg Mirsky | ||
| Last updated | 2015-10-18 | ||
| Replaced by | draft-ietf-bfd-vxlan, RFC 8971 | ||
| RFC stream | (None) | ||
| Formats | |||
| Additional resources | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-spallagatti-bfd-vxlan-02
Internet Engineering Task Force S. Pallagatti, Ed.
Internet-Draft B. Saji
Intended status: Standards Track S. Paragiri
Expires: April 20, 2016 Juniper Networks
V. Govindan
M. Mudigonda
Cisco
G. Mirsky
Ericsson
October 18, 2015
BFD for VXLAN
draft-spallagatti-bfd-vxlan-02
Abstract
This document describes use of Bidirectional Forwarding Detection
(BFD) protocol for VXLAN .
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 20, 2016.
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Deployment . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. BFD Packet Transmission . . . . . . . . . . . . . . . . . . . 5
4.1. BFD Packet Encapsulation . . . . . . . . . . . . . . . . 5
5. Reception of BFD packet . . . . . . . . . . . . . . . . . . . 6
5.1. Demultiplexing of the BFD packet . . . . . . . . . . . . 6
6. Use of reserved VNI . . . . . . . . . . . . . . . . . . . . . 6
7. Echo BFD . . . . . . . . . . . . . . . . . . . . . . . . . . 6
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
9. Security Considerations . . . . . . . . . . . . . . . . . . . 7
10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 7
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
12. Normative References . . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
"Virtual eXtensible Local Area Network (VXLAN)" has been defined in
[RFC7348] that provides an encapsulation scheme which allows VM's to
communicate in data center network.
VXLAN is typically deployed in data centers interconnecting
virtualized hosts, which may be spread across multiple racks. The
individual racks may be part of a different Layer 3 network or they
could be in a single Layer 2 network. The VXLAN segments/overlay
networks are overlaid on top of these Layer 2 or Layer 3 networks.
A virtual machine (VM) can communicate with a VM in other host only
if they are on same VXLAN. VM's are unaware of VXLAN tunnels as
VXLAN tunnel is terminated on VXLAN Tunnel End Point(VTEP)
(hypervisor/TOR). VTEPs (hypervisor/TOR) are responsible for
encapsulating and decapsulating frames exchanged among VM's.
Since underlay is a L3 network, continuity check for these tunnels
becomes important. BFD as defined in [RFC5880] can be used to
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monitor the VXLAN tunnels. Use of [I-D.ietf-bfd-multipoint] is for
future study.
This draft addresses requirements outlined in
[I-D.ashwood-nvo3-operational-requirement]. Specifically with
reference to the OAM model to Figure 3 of
[I-D.ashwood-nvo3-operational-requirement], this draft outlines
proposal to implement the OAM mechanism between the NV Edges using
BFD.
2. Use cases
Main use case of BFD for VXLAN is for tunnel continuity check. BFD
packets between VTEPs will exercise the VXLAN path in underlay/
overlay ensuring the VXLAN path reachability. BFD failure detection
can be used for maintenance. There are other use cases such as
Layer 2 VM's:
Most deployments will have VM's with only L2 capabilities that
may not support L3. BFD being a L3 protocol can be used as
tunnel CC mechanism, where BFD will start and terminate at the
Network Virtualization (NV) Edge (VTEPs).
It is possible to aggregate the CC sessions for multiple
tenants by running a BFD session between the VTEPs over VxLAN
tunnel. In rest of this document terms NV Edge and VTEP are
used interchangeably.
Fault localization:
It is also possible that VM's are L3 aware and can possibly
host a BFD session. In these cases BFD sessions can be
established among VM's for CC. In addition BFD sessions can be
established among VTEPs for tunnel CC. Having a hierarchical
OAM model helps localize faults though requires additional
consideration.
Service node reachability:
Service node is responsible for sending BUM traffic. In case
of service node tunnel terminates at VTEP and it might not even
host VM's. BFD session between TOR/hypervisor and service node
can be used to monitor service node reachability.
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3. Deployment
+------------+-------------+
| Server 1 |
| |
| +----+----+ +----+----+ |
| |VM1-1 | |VM1-2 | |
| |VNI 100 | |VNI 200 | |
| | | | | |
| +---------+ +---------+ |
| Hypervisor VTEP (IP1) |
+--------------------------+
|
|
|
| +-------------+
| | Layer 3 |
|---| Network |
| |
+-------------+
|
|
+-----------+
|
|
+------------+-------------+
| Hypervisor VTEP (IP2) |
| +----+----+ +----+----+ |
| |VM2-1 | |VM2-2 | |
| |VNI 100 | |VNI 200 | |
| | | | | |
| +---------+ +---------+ |
| Server 2 |
+--------------------------+
Figure 1
Figure 1 illustrates the scenario where we have two servers, each of
them hosting two VMs. These VTEPs terminate two VXLAN tunnels with
VNI number 100 and 200 between them. 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 software or a physical device.
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4. BFD Packet Transmission
BFD packet MUST be encapsulated and sent to remote VTEP as explained
in Section 4.1. Implementations SHOULD ensure that the BFD packets
follow the same lookup path of VXLAN packets within the sender
system.
4.1. BFD Packet Encapsulation
VXLAN packet format has been defined in Section 5 of [RFC7348]. The
Outer IP/UDP and VXLAN headers MUST be encoded by the sender as per
[RFC7348].
If VTEP is equipped with Generic Protocol Extension (GPE) header
capabilities and decides to use GPE instead of VXLAN then GPE header
MUST be encoded as per Section 3.3 of [I-D.quinn-vxlan-gpe]. Next
Protocol Field in GPE header MUST be set to IPv4 or IPv6.
Details of how VTEP decides to use VXLAN or GPE header are outside
the scope of this document.
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
following format:
Ethernet Header:
Destination MAC: This MUST be a well-known MAC [TBD] OR the MAC
address of the destination VTEP. The details of how the
destination MAC address is obtained are outside the scope of
this document.
Source MAC: MAC address of the originating VTEP
IP header:
Source IP: IP address of the originating VTEP.
Destination IP: IP address of the terminating VTEP.
TTL: This MUST be set to 1. This is to ensure that the BFD
packet is not routed within the L3 underlay network.
[Ed.Note]:Use of inner source and destination IP addresses
needs more discussion by the WG.
The fields of the UDP header and the BFD control packet are
encoded as specified in RFC 5881 for p2p VXLAN tunnels.
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5. Reception of BFD packet
Once a packet is received, VTEP MUST validate the packet as described
in Section 4.1 of [RFC7348]. If the Destination MAC of the inner MAC
frame matches the well-known MAC or the MAC address of the VTEP the
packet MUST be processed further.
The UDP destination port and the TTL of the inner MAC frame MUST be
validated to determine if the received packet can be processed by
BFD. BFD packet with inner MAC set to VTEP or well-known MAC address
MUST not be forwarded to VM's.
To ensure BFD detects the proper configuration of VXLAN Network
Identifier(VNI) in a remote VTEP, a lookup SHOULD be performed with
the MAC-DA and VNI as key in the Virtual Forwarding Instance(VFI)
table of the originating/ terminating VTEP in order to exercise the
VFI associated with the VNI.
5.1. Demultiplexing of the BFD packet
Demultiplexing of IP BFD packet has been defined in Section 3 of
[RFC5881]. Since multiple BFD sessions may be running between two
VTEPs, there needs to be a mechanism for demultiplexing received BFD
packets to the proper session. The procedure for demultiplexing
packets with Your Discriminator = 0 is different from [RFC5880]. For
such packets, the BFD session MUST be identified using the inner
headers, i.e. the source IP and the destination IP present in the IP
header carried by the payload of the VXLAN encapsulated packet. The
VNI of the packet SHOULD be used to derive interface related
information for demultiplexing the packet. If BFD packet is received
with non-zero your discriminator then BFD session should be
demultiplexed only with your discriminator as the key.
6. Use of reserved VNI
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
with VNI 0. A VTEP MAY also use VNI 0 to establish a BFD session
with a service node.
7. Echo BFD
Support for echo BFD is outside the scope of this document.
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8. IANA Considerations
The well-known MAC to be used for the Destination MAC address of the
inner MAC frame needs to be defined
9. Security Considerations
Document recommends setting of inner IP TTL to 1 which could lead to
DDoS attack, implementation MUST have throttling in place.
Throttling MAY be relaxed for BFD packeted based on port number.
Other than inner IP TTL set to 1 this specification does not raise
any additional security issues beyond those of the specifications
referred to in the list of normative references.
10. Contributors
Reshad Rahman
rrahman@cisco.com
Cisco
11. Acknowledgements
Authors would like to thank Jeff Hass of Juniper Networks for his
reviews and feedback on this material.
Authors would also like to thank Nobo Akiya, Marc Binderberger and
Shahram Davari for the extensive review.
12. 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]
Katz, D., Ward, D., and J. Networks, "BFD for Multipoint
Networks", draft-ietf-bfd-multipoint-07 (work in
progress), August 2015.
[I-D.ietf-bfd-seamless-base]
Akiya, N., Pignataro, C., Ward, D., Bhatia, M., and J.
Networks, "Seamless Bidirectional Forwarding Detection
(S-BFD)", draft-ietf-bfd-seamless-base-05 (work in
progress), June 2015.
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[I-D.quinn-vxlan-gpe]
Quinn, P., Manur, R., Kreeger, L., Lewis, D., Maino, F.,
Smith, M., Agarwal, P., Yong, L., Xu, X., Elzur, U., Garg,
P., and D. Melman, "Generic Protocol Extension for VXLAN",
draft-quinn-vxlan-gpe-04 (work in progress), February
2015.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,
<http://www.rfc-editor.org/info/rfc5880>.
[RFC5881] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD) for IPv4 and IPv6 (Single Hop)", RFC 5881,
DOI 10.17487/RFC5881, June 2010,
<http://www.rfc-editor.org/info/rfc5881>.
[RFC7348] Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger,
L., Sridhar, T., Bursell, M., and C. Wright, "Virtual
eXtensible Local Area Network (VXLAN): A Framework for
Overlaying Virtualized Layer 2 Networks over Layer 3
Networks", RFC 7348, DOI 10.17487/RFC7348, August 2014,
<http://www.rfc-editor.org/info/rfc7348>.
Authors' Addresses
Santosh Pallagatti (editor)
Juniper Networks
Embassy Business Park
Bangalore, KA 560093
India
Email: santoshpk@juniper.net
Basil Saji
Juniper Networks
Embassy Business Park
Bangalore, KA 560093
India
Email: sbasil@juniper.net
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Sudarsan Paragiri
Juniper Networks
1194 N. Mathilda Ave.
Sunnyvale, California 94089-1206
USA
Email: sparagiri@juniper.net
Vengada Prasad Govindan
Cisco
Email: venggovi@cisco.com
Mallik Mudigonda
Cisco
Email: mmudigon@cisco.com
Greg Mirsky
Ericsson
Email: gregory.mirsky@ericsson.com
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