Internet DRAFT - draft-xiao-bfd-geneve
draft-xiao-bfd-geneve
BFD Working Group X. Min
Internet-Draft G. Mirsky
Intended status: Standards Track ZTE
Expires: May 27, 2019 November 23, 2018
BFD for Geneve
draft-xiao-bfd-geneve-00
Abstract
This document describes the use of the Bidirectional Forwarding
Detection (BFD) protocol in Generic Network Virtualization
Encapsulation (Geneve) overlay networks.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on May 27, 2019.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Conventions Used in This Document . . . . . . . . . . . . 2
1.1.1. Terminology . . . . . . . . . . . . . . . . . . . . . 2
1.1.2. Requirements Language . . . . . . . . . . . . . . . . 3
2. BFD Packet Transmission over Geneve Tunnel . . . . . . . . . 3
2.1. BFD Packet Encapsulation in Geneve . . . . . . . . . . . 3
2.1.1. BFD Encapsulation With IP/UDP Header . . . . . . . . 3
2.1.2. BFD Encapsulation Without IP/UDP Header . . . . . . . 5
3. Reception of BFD packet from Geneve Tunnel . . . . . . . . . 7
3.1. Demultiplexing of the BFD packet . . . . . . . . . . . . 8
4. Security Considerations . . . . . . . . . . . . . . . . . . . 8
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
7. Normative References . . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
"Generic Network Virtualization Encapsulation" (Geneve)
[I-D.ietf-nvo3-geneve] provides a generic tunneling protocol that is
applicable to many scenarios, including an encapsulation scheme that
allows virtual machines (VMs) to communicate in a data center
network.
This document describes the use of Bidirectional Forwarding Detection
(BFD) protocol for Geneve to enable monitoring continuity of the path
between Network Virtualization Edges (NVEs) and/or availability of a
replicator service node using BFD.
The use cases and the deployment of BFD for Geneve are consistent
with what's described in Section 3 and Section 4 of
[I-D.ietf-bfd-vxlan]. The main difference between Geneve and
"Virtual eXtensible Local Area Network" (VXLAN) [RFC7348]
encapsulation is that Geneve supports multi-protocol payload and
variable length options.
1.1. Conventions Used in This Document
1.1.1. Terminology
BFD: Bidirectional Forwarding Detection
Geneve: Generic Network Virtualization Encapsulation
NVE: Network Virtualization Edge
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VFI: Virtual Forwarding Instance
VM: Virtual Machine
VNI: Virtual Network Identifier
VXLAN: Virtual eXtensible Local Area Network
1.1.2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"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.
2. BFD Packet Transmission over Geneve Tunnel
BFD packet MUST be encapsulated and sent to a remote NVE using one of
the options described in Section 2.1. Implementations SHOULD ensure
that the BFD packets follow the same lookup path as Geneve data
packets within the sender system.
2.1. BFD Packet Encapsulation in Geneve
Concerning whether or not the Geneve data packets include an IP
protocol data unit, this document defines three options of BFD packet
encapsulation in Geneve.
2.1.1. BFD Encapsulation With IP/UDP Header
If the Protocol Type field (as defined in Section 3.4 of
[I-D.ietf-nvo3-geneve]) of data packets indicates that there exists
an inner IP header, i.e., the Protocol Type equals to 0x6558
(Ethernet frame), or 0x0800 (IPv4), or 0x86DD (IPv6), or 0x8847
(MPLS), or 0x8848 (MPLS with the upstream-assigned label), then BFD
packets are encapsulated in Geneve as described below. The Geneve
packet format over IPv4 is defined in Section 3.1 of
[I-D.ietf-nvo3-geneve]. The Geneve packet format over IPv6 is
defined in Section 3.2 of [I-D.ietf-nvo3-geneve]. The Outer IP/UDP
and Geneve headers MUST be encoded by the sender as defined in
[I-D.ietf-nvo3-geneve]. Note that the outer IP header and the inner
IP header may not be of the same address family, in other words,
outer IPv6 header accompanied with inner IPv4 header and outer IPv4
header accompanied with inner IPv6 header are both possible.
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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 ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Geneve Header ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Inner IPvX Header ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Inner UDP Header ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ BFD Control Message ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FCS |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Geneve Encapsulation of BFD Control Message With the Inner
IP/UDP Header
When the BFD packets are encapsulated in Geneve in this way, the BFD
packet MUST be carried inside the inner IP packet of the Geneve
packet. The inner IP packet carrying the BFD payload has the
following format:
IP header:
Source IP: IP address of the originating NVE.
Destination IP: IP address of the terminating NVE.
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TTL: MUST be set to 1 to ensure that the BFD packet is not
routed within the L3 underlay network.
The fields of the UDP header and the BFD control packet are
encoded as specified in [RFC5881].
When the BFD packets are encapsulated in Geneve in this way, the
Geneve header SHOULD follow the value set below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Ver| Opt Len |O|C| Rsvd. | Protocol Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Virtual Network Identifier (VNI) | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Variable Length Options |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Geneve Header
Opt Len field SHOULD be set to 0, which indicates there isn't any
variable length option.
[Ed.Note]: Use of O bit is still being discussed in the NVO3 WG, so
the value is undetermined.
C bit SHOULD be set to 0.
Protocol Type field SHOULD be set to 0x0800 (IPv4) or 0x86DD (IPv6).
2.1.2. BFD Encapsulation Without IP/UDP Header
Alternatively to the use of the inner IP/UDP header to demultiplex
BFD control packet by the value of the destination UDP port, BFD
control packet MAY be encapsulated without the inner IP/UDP header.
The BFD control packet MAY be identified directly in the Geneve
header or through Geneve OAM shim. In either case, the Outer IP/UDP
and Geneve headers MUST be encoded by the sender as defined in
[I-D.ietf-nvo3-geneve].
Figure 3 displays the layout of the Ethernet frame with BFD control
packet encapsulated in Geneve without the use of IP/UDP header and
identified by the value TBA1 (to be assigned by IANA) of the Protocol
Type field.
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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 ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Geneve Header ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ BFD Control Message ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FCS |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Geneve Encapsulation of BFD Control Message Without the
Inner IP/UDP Header
When the BFD packets are encapsulated in Geneve in this way, the BFD
packet MUST immediately follow the Geneve header, and the Geneve
header SHOULD follow the value set below.
Opt Len field SHOULD be set to 0, which indicates there isn't any
variable length option.
[Ed.Note]: Use of O bit is still being discussed in the NVO3 WG, so
the value is undetermined.
C bit SHOULD be set to 0.
Also, if BFD control packet is encapsulated in Geneve without the use
of IP/UDP header, the BFD control packet MAY be identified through
the Geneve OAM shim. The layout of the Ethernet frame is shown in
Figure 4. Protocol Type field MUST be set to the value TBA2 (to be
assigned by IANA) which indicates a Geneve OAM shim that will have a
field to indicate the inner BFD control packet. Definition of the
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format of the Geneve OAM shim is outside the scope of this document.
The Geneve OAM shim immediately follows the Geneve header, and the
BFD control packet immediately follows the Geneve OAM shim.
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 ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Geneve Header ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Geneve OAM Shim |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ BFD Control Message ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FCS |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Geneve Encapsulation of BFD Control Message With Geneve OAM
Shim
3. Reception of BFD packet from Geneve Tunnel
Once a packet is received, NVE MUST validate the packet as described
in [I-D.ietf-nvo3-geneve].
If the Protocol Type field equals 0x0800 (IPv4) or 0x86DD (IPv6), and
the Destination IP of the inner IP packet matches the IP address of
the NVE, the UDP destination port and the TTL of the inner IP packet
MUST be validated to determine whether BFD can process the received
packet. BFD packet with inner IP set to NVE MUST NOT be forwarded to
VMs.
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If the Protocol Type field equals the value TBA1 (to be assigned by
IANA) which indicates an inner BFD control message, the received
packet MUST be processed by BFD and MUST NOT be forwarded to VMs.
If the Protocol Type field equals the value TBA2 (to be assigned by
IANA) which indicates a Geneve OAM shim that will have a field to
indicate the inner BFD control message, the received packet MUST be
processed by BFD and MUST NOT be forwarded to VMs. This case is for
further study.
To ensure BFD detects the proper configuration of Virtual Network
Identifier (VNI) in a remote NVE, a lookup SHOULD be performed with
the MAC-DA/IP-DA/MPLS-Label and VNI as key in the Virtual Forwarding
Instance (VFI) table of the originating/terminating NVE to exercise
the VFI associated with the VNI.
3.1. Demultiplexing of the BFD packet
If the Protocol Type field equals 0x0800 (IPv4) or 0x86DD (IPv6),
demultiplexing of IP BFD packet has been defined in Section 3 of
[RFC5881]. Since multiple BFD sessions may be running between two
NVEs, there needs to be a mechanism for demultiplexing received BFD
packets to the proper session. The procedure for demultiplexing
packets with Your Discriminator equal to 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 Geneve
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
MUST be demultiplexed only with Your Discriminator as the key.
If the Protocol Type field equals the value TBA1 (to be assigned by
IANA) which indicates an inner BFD control message, or the value TBA2
(to be assigned by IANA) which indicates a Geneve OAM shim that will
have a field to indicate the inner BFD control message, the VNI of
the packet SHOULD be used to derive interface-related information for
demultiplexing the packet, demultiplexing of BFD packet MUST rely on
non-zero Your Discriminator as the key.
4. Security Considerations
This document does not raise any additional security issues beyond
those of the specifications referred to in the list of normative
references.
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5. IANA Considerations
In the Geneve Protocol Type registry defined in [ETYPES], a new BFD
Control Message or Geneve OAM Shim is requested from IANA as follows:
+----------------+-----------------+------------------+-------------+
| Geneve | Description | Semantics | Reference |
| Protocol Type | | Definition | |
+----------------+-----------------+------------------+-------------+
| TBA1 | BFD Control | Section 3.1 | This |
| | Message | | Document |
| TBA2 | Geneve OAM Shim | Section 3.1 | This |
| | | | Document |
+----------------+-----------------+------------------+-------------+
Table 1: New BFD Control Message or Geneve OAM shim Ethertype
6. Acknowledgements
To be added.
7. Normative References
[ETYPES] The IEEE Registration Authority, "IEEE 802 Numbers", 2013,
<http://www.iana.org/assignments/ieee-802-numbers/
ieee-802-numbers.xml>.
[I-D.ietf-bfd-vxlan]
Networks, J., Paragiri, S., Govindan, V., Mudigonda, M.,
and G. Mirsky, "BFD for VXLAN", draft-ietf-bfd-vxlan-03
(work in progress), October 2018.
[I-D.ietf-nvo3-geneve]
Gross, J., Ganga, I., and T. Sridhar, "Geneve: Generic
Network Virtualization Encapsulation", draft-ietf-
nvo3-geneve-08 (work in progress), October 2018.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,
<https://www.rfc-editor.org/info/rfc5880>.
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[RFC5881] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD) for IPv4 and IPv6 (Single Hop)", RFC 5881,
DOI 10.17487/RFC5881, June 2010,
<https://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,
<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
Xiao Min
ZTE
Nanjing
China
Phone: +86 25 88016574
Email: xiao.min2@zte.com.cn
Greg Mirsky
ZTE
USA
Email: gregimirsky@gmail.com
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