draft-ietf-nvo3-geneve-14.txt   draft-ietf-nvo3-geneve-15.txt 
Network Working Group J. Gross, Ed. Network Working Group J. Gross, Ed.
Internet-Draft Internet-Draft
Intended status: Standards Track I. Ganga, Ed. Intended status: Standards Track I. Ganga, Ed.
Expires: March 15, 2020 Intel Expires: September 1, 2020 Intel
T. Sridhar, Ed. T. Sridhar, Ed.
VMware VMware
September 12, 2019 February 29, 2020
Geneve: Generic Network Virtualization Encapsulation Geneve: Generic Network Virtualization Encapsulation
draft-ietf-nvo3-geneve-14 draft-ietf-nvo3-geneve-15
Abstract Abstract
Network virtualization involves the cooperation of devices with a Network virtualization involves the cooperation of devices with a
wide variety of capabilities such as software and hardware tunnel wide variety of capabilities such as software and hardware tunnel
endpoints, transit fabrics, and centralized control clusters. As a endpoints, transit fabrics, and centralized control clusters. As a
result of their role in tying together different elements in the result of their role in tying together different elements in the
system, the requirements on tunnels are influenced by all of these system, the requirements on tunnels are influenced by all of these
components. Flexibility is therefore the most important aspect of a components. Flexibility is therefore the most important aspect of a
tunnel protocol if it is to keep pace with the evolution of the tunnel protocol if it is to keep pace with the evolution of the
skipping to change at page 1, line 42 skipping to change at page 1, line 42
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This Internet-Draft will expire on March 15, 2020. This Internet-Draft will expire on September 1, 2020.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. Design Requirements . . . . . . . . . . . . . . . . . . . . . 5 2. Design Requirements . . . . . . . . . . . . . . . . . . . . . 6
2.1. Control Plane Independence . . . . . . . . . . . . . . . 6 2.1. Control Plane Independence . . . . . . . . . . . . . . . 7
2.2. Data Plane Extensibility . . . . . . . . . . . . . . . . 7 2.2. Data Plane Extensibility . . . . . . . . . . . . . . . . 7
2.2.1. Efficient Implementation . . . . . . . . . . . . . . 7 2.2.1. Efficient Implementation . . . . . . . . . . . . . . 8
2.3. Use of Standard IP Fabrics . . . . . . . . . . . . . . . 8 2.3. Use of Standard IP Fabrics . . . . . . . . . . . . . . . 8
3. Geneve Encapsulation Details . . . . . . . . . . . . . . . . 9 3. Geneve Encapsulation Details . . . . . . . . . . . . . . . . 9
3.1. Geneve Packet Format Over IPv4 . . . . . . . . . . . . . 9 3.1. Geneve Packet Format Over IPv4 . . . . . . . . . . . . . 9
3.2. Geneve Packet Format Over IPv6 . . . . . . . . . . . . . 10 3.2. Geneve Packet Format Over IPv6 . . . . . . . . . . . . . 11
3.3. UDP Header . . . . . . . . . . . . . . . . . . . . . . . 12 3.3. UDP Header . . . . . . . . . . . . . . . . . . . . . . . 13
3.4. Tunnel Header Fields . . . . . . . . . . . . . . . . . . 13 3.4. Tunnel Header Fields . . . . . . . . . . . . . . . . . . 14
3.5. Tunnel Options . . . . . . . . . . . . . . . . . . . . . 14 3.5. Tunnel Options . . . . . . . . . . . . . . . . . . . . . 15
3.5.1. Options Processing . . . . . . . . . . . . . . . . . 16 3.5.1. Options Processing . . . . . . . . . . . . . . . . . 17
4. Implementation and Deployment Considerations . . . . . . . . 17 4. Implementation and Deployment Considerations . . . . . . . . 18
4.1. Applicability Statement . . . . . . . . . . . . . . . . . 17 4.1. Applicability Statement . . . . . . . . . . . . . . . . . 18
4.2. Congestion Control Functionality . . . . . . . . . . . . 18 4.2. Congestion Control Functionality . . . . . . . . . . . . 19
4.3. UDP Checksum . . . . . . . . . . . . . . . . . . . . . . 18 4.3. UDP Checksum . . . . . . . . . . . . . . . . . . . . . . 19
4.3.1. UDP Zero Checksum Handling with IPv6 . . . . . . . . 19 4.3.1. UDP Zero Checksum Handling with IPv6 . . . . . . . . 19
4.4. Encapsulation of Geneve in IP . . . . . . . . . . . . . . 20 4.4. Encapsulation of Geneve in IP . . . . . . . . . . . . . . 21
4.4.1. IP Fragmentation . . . . . . . . . . . . . . . . . . 21 4.4.1. IP Fragmentation . . . . . . . . . . . . . . . . . . 21
4.4.2. DSCP, ECN and TTL . . . . . . . . . . . . . . . . . . 21 4.4.2. DSCP, ECN and TTL . . . . . . . . . . . . . . . . . . 22
4.4.3. Broadcast and Multicast . . . . . . . . . . . . . . . 22 4.4.3. Broadcast and Multicast . . . . . . . . . . . . . . . 23
4.4.4. Unidirectional Tunnels . . . . . . . . . . . . . . . 23 4.4.4. Unidirectional Tunnels . . . . . . . . . . . . . . . 23
4.5. Constraints on Protocol Features . . . . . . . . . . . . 23 4.5. Constraints on Protocol Features . . . . . . . . . . . . 24
4.5.1. Constraints on Options . . . . . . . . . . . . . . . 23 4.5.1. Constraints on Options . . . . . . . . . . . . . . . 24
4.6. NIC Offloads . . . . . . . . . . . . . . . . . . . . . . 24 4.6. NIC Offloads . . . . . . . . . . . . . . . . . . . . . . 25
4.7. Inner VLAN Handling . . . . . . . . . . . . . . . . . . . 24 4.7. Inner VLAN Handling . . . . . . . . . . . . . . . . . . . 25
5. Interoperability Issues . . . . . . . . . . . . . . . . . . . 25 5. Transition Considerations . . . . . . . . . . . . . . . . . . 26
6. Security Considerations . . . . . . . . . . . . . . . . . . . 25 6. Security Considerations . . . . . . . . . . . . . . . . . . . 26
6.1. Data Confidentiality . . . . . . . . . . . . . . . . . . 26 6.1. Data Confidentiality . . . . . . . . . . . . . . . . . . 27
6.1.1. Inter-Data Center Traffic . . . . . . . . . . . . . . 26 6.1.1. Inter-Data Center Traffic . . . . . . . . . . . . . . 27
6.2. Data Integrity . . . . . . . . . . . . . . . . . . . . . 27 6.2. Data Integrity . . . . . . . . . . . . . . . . . . . . . 28
6.3. Authentication of NVE peers . . . . . . . . . . . . . . . 27 6.3. Authentication of NVE peers . . . . . . . . . . . . . . . 29
6.4. Options Interpretation by Transit Devices . . . . . . . . 28 6.4. Options Interpretation by Transit Devices . . . . . . . . 29
6.5. Multicast/Broadcast . . . . . . . . . . . . . . . . . . . 28 6.5. Multicast/Broadcast . . . . . . . . . . . . . . . . . . . 29
6.6. Control Plane Communications . . . . . . . . . . . . . . 28 6.6. Control Plane Communications . . . . . . . . . . . . . . 29
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 30
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 29 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 31
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 30 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 32
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 31 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 33
10.1. Normative References . . . . . . . . . . . . . . . . . . 31 10.1. Normative References . . . . . . . . . . . . . . . . . . 33
10.2. Informative References . . . . . . . . . . . . . . . . . 32 10.2. Informative References . . . . . . . . . . . . . . . . . 34
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 35 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 37
1. Introduction 1. Introduction
Networking has long featured a variety of tunneling, tagging, and Networking has long featured a variety of tunneling, tagging, and
other encapsulation mechanisms. However, the advent of network other encapsulation mechanisms. However, the advent of network
virtualization has caused a surge of renewed interest and a virtualization has caused a surge of renewed interest and a
corresponding increase in the introduction of new protocols. The corresponding increase in the introduction of new protocols. The
large number of protocols in this space, ranging all the way from large number of protocols in this space, for example, ranging all the
VLANs [IEEE.802.1Q_2014] and MPLS [RFC3031] through the more recent way from VLANs [IEEE.802.1Q_2018] and MPLS [RFC3031] through the more
VXLAN [RFC7348] (Virtual eXtensible Local Area Network) and NVGRE recent VXLAN [RFC7348] (Virtual eXtensible Local Area Network) and
[RFC7637] (Network Virtualization Using Generic Routing NVGRE [RFC7637] (Network Virtualization Using Generic Routing
Encapsulation), often leads to questions about the need for new Encapsulation), often leads to questions about the need for new
encapsulation formats and what it is about network virtualization in encapsulation formats and what it is about network virtualization in
particular that leads to their proliferation. particular that leads to their proliferation. Note that the list of
protocols presented above is non-exhaustive.
While many encapsulation protocols seek to simply partition the While many encapsulation protocols seek to simply partition the
underlay network or bridge between two domains, network underlay network or bridge between two domains, network
virtualization views the transit network as providing connectivity virtualization views the transit network as providing connectivity
between multiple components of a distributed system. In many ways between multiple components of a distributed system. In many ways
this system is similar to a chassis switch with the IP underlay this system is similar to a chassis switch with the IP underlay
network playing the role of the backplane and tunnel endpoints on the network playing the role of the backplane and tunnel endpoints on the
edge as line cards. When viewed in this light, the requirements edge as line cards. When viewed in this light, the requirements
placed on the tunnel protocol are significantly different in terms of placed on the tunnel protocol are significantly different in terms of
the quantity of metadata necessary and the role of transit nodes. the quantity of metadata necessary and the role of transit nodes.
Current work such as [VL2] (A Scalable and Flexible Data Center Work such as [VL2] (A Scalable and Flexible Data Center Network) and
Network) and the NVO3 Data Plane Requirements the NVO3 Data Plane Requirements
[I-D.ietf-nvo3-dataplane-requirements] have described some of the [I-D.ietf-nvo3-dataplane-requirements] have described some of the
properties that the data plane must have to support network properties that the data plane must have to support network
virtualization. However, one additional defining requirement is the virtualization. However, one additional defining requirement is the
need to carry system state along with the packet data. The use of need to carry metadata (e.g. system state) along with the packet
some metadata is certainly not a foreign concept - nearly all data; example use cases of metadata are noted below. The use of some
protocols used for virtualization have at least 24 bits of identifier metadata is certainly not a foreign concept - nearly all protocols
used for network virtualization have at least 24 bits of identifier
space as a way to partition between tenants. This is often described space as a way to partition between tenants. This is often described
as overcoming the limits of 12-bit VLANs, and when seen in that as overcoming the limits of 12-bit VLANs, and when seen in that
context, or any context where it is a true tenant identifier, 16 context, or any context where it is a true tenant identifier, 16
million possible entries is a large number. However, the reality is million possible entries is a large number. However, the reality is
that the metadata is not exclusively used to identify tenants and that the metadata is not exclusively used to identify tenants and
encoding other information quickly starts to crowd the space. In encoding other information quickly starts to crowd the space. In
fact, when compared to the tags used to exchange metadata between fact, when compared to the tags used to exchange metadata between
line cards on a chassis switch, 24-bit identifiers start to look line cards on a chassis switch, 24-bit identifiers start to look
quite small. There are nearly endless uses for this metadata, quite small. There are nearly endless uses for this metadata,
ranging from storing input ports for simple security policies to ranging from storing input port identifiers for simple security
service based context for interposing advanced middleboxes. policies to sending service based context for advanced middlebox
applications that terminate and re-encapsulate Geneve traffic.
Existing tunnel protocols have each attempted to solve different Existing tunnel protocols have each attempted to solve different
aspects of these new requirements, only to be quickly rendered out of aspects of these new requirements, only to be quickly rendered out of
date by changing control plane implementations and advancements. date by changing control plane implementations and advancements.
Furthermore, software and hardware components and controllers all Furthermore, software and hardware components and controllers all
have different advantages and rates of evolution - a fact that should have different advantages and rates of evolution - a fact that should
be viewed as a benefit, not a liability or limitation. This draft be viewed as a benefit, not a liability or limitation. This draft
describes Geneve, a protocol which seeks to avoid these problems by describes Geneve, a protocol which seeks to avoid these problems by
providing a framework for tunneling for network virtualization rather providing a framework for tunneling for network virtualization rather
than being prescriptive about the entire system. than being prescriptive about the entire system.
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1.1. Requirements Language 1.1. 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", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
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.
1.2. Terminology 1.2. Terminology
The NVO3 framework [RFC7365] defines many of the concepts commonly The NVO3 Framework [RFC7365] defines many of the concepts commonly
used in network virtualization. In addition, the following terms are used in network virtualization. In addition, the following terms are
specifically meaningful in this document: specifically meaningful in this document:
Checksum offload. An optimization implemented by many NICs (Network Checksum offload. An optimization implemented by many NICs (Network
Interface Controller) which enables computation and verification of Interface Controller) which enables computation and verification of
upper layer protocol checksums in hardware on transmit and receive, upper layer protocol checksums in hardware on transmit and receive,
respectively. This typically includes IP and TCP/UDP checksums which respectively. This typically includes IP and TCP/UDP checksums which
would otherwise be computed by the protocol stack in software. would otherwise be computed by the protocol stack in software.
Clos network. A technique for composing network fabrics larger than Clos network. A technique for composing network fabrics larger than
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to better utilize network bandwidth while avoiding reordering of to better utilize network bandwidth while avoiding reordering of
packets within a flow. packets within a flow.
Geneve. Generic Network Virtualization Encapsulation. The tunnel Geneve. Generic Network Virtualization Encapsulation. The tunnel
protocol described in this document. protocol described in this document.
LRO. Large Receive Offload. The receive-side equivalent function of LRO. Large Receive Offload. The receive-side equivalent function of
LSO, in which multiple protocol segments (primarily TCP) are LSO, in which multiple protocol segments (primarily TCP) are
coalesced into larger data units. coalesced into larger data units.
LSO. Large Segmentation Offload. A function provided by many
commercial NICs that allows data units larger than the MTU to be
passed to the NIC to improve performance, the NIC being responsible
for creating smaller segments of size less than or equal to the MTU
with correct protocol headers. When referring specifically to TCP/
IP, this feature is often known as TSO (TCP Segmentation Offload).
Middlebox. The term middlebox in the context of this document refers
to network service functions or appliances for service interposition
that would typically implement NVE functionality, which terminate or
re-encapsulate Geneve traffic.
NIC. Network Interface Controller. Also called as Network Interface NIC. Network Interface Controller. Also called as Network Interface
Card or Network Adapter. A NIC could be part of a tunnel endpoint or Card or Network Adapter. A NIC could be part of a tunnel endpoint or
transit device and can either process Geneve packets or aid in the transit device and can either process Geneve packets or aid in the
processing of Geneve packets. processing of Geneve packets.
Transit device. A forwarding element (e.g. router or switch) along Transit device. A forwarding element (e.g. router or switch) along
the path of the tunnel making up part of the Underlay Network. A the path of the tunnel making up part of the Underlay Network. A
transit device MAY be capable of understanding the Geneve packet transit device may be capable of understanding the Geneve packet
format but does not originate or terminate Geneve packets. format but does not originate or terminate Geneve packets.
LSO. Large Segmentation Offload. A function provided by many
commercial NICs that allows data units larger than the MTU to be
passed to the NIC to improve performance, the NIC being responsible
for creating smaller segments of size less than or equal to the MTU
with correct protocol headers. When referring specifically to TCP/
IP, this feature is often known as TSO (TCP Segmentation Offload).
Tunnel endpoint. A component performing encapsulation and Tunnel endpoint. A component performing encapsulation and
decapsulation of packets, such as Ethernet frames or IP datagrams, in decapsulation of packets, such as Ethernet frames or IP datagrams, in
Geneve headers. As the ultimate consumer of any tunnel metadata, Geneve headers. As the ultimate consumer of any tunnel metadata,
tunnel endpoints have the highest level of requirements for parsing tunnel endpoints have the highest level of requirements for parsing
and interpreting tunnel headers. Tunnel endpoints may consist of and interpreting tunnel headers. Tunnel endpoints may consist of
either software or hardware implementations or a combination of the either software or hardware implementations or a combination of the
two. Tunnel endpoints are frequently a component of an NVE (Network two. Tunnel endpoints are frequently a component of an NVE (Network
Virtualization Edge) but may also be found in middleboxes or other Virtualization Edge) but may also be found in middleboxes or other
elements making up an NVO3 Network. elements making up an NVO3 Network.
VM. Virtual Machine. VM. Virtual Machine.
2. Design Requirements 2. Design Requirements
Geneve is designed to support network virtualization use cases, where Geneve is designed to support network virtualization use cases for
tunnels are typically established to act as a backplane between the data center environments, where tunnels are typically established to
virtual switches residing in hypervisors, physical switches, or act as a backplane between the virtual switches residing in
middleboxes or other appliances. An arbitrary IP network can be used hypervisors, physical switches, or middleboxes or other appliances.
as an underlay although Clos networks composed using ECMP links are a An arbitrary IP network can be used as an underlay although Clos
common choice to provide consistent bisectional bandwidth across all networks composed using ECMP links are a common choice to provide
connection points. Many of the concepts of network virtualization consistent bisectional bandwidth across all connection points. Many
overlays over Layer 3 IP networks are described in NVO3 Framework of the concepts of network virtualization overlays over Layer 3 IP
framework [RFC7365]. Figure 1 shows an example of a hypervisor, top networks are described in the NVO3 Framework [RFC7365]. Figure 1
of rack switch for connectivity to physical servers, and a WAN uplink shows an example of a hypervisor, top of rack switch for connectivity
connected using Geneve tunnels over a simplified Clos network. These to physical servers, and a WAN uplink connected using Geneve tunnels
tunnels are used to encapsulate and forward frames from the attached over a simplified Clos network. These tunnels are used to
components such as VMs or physical links. encapsulate and forward frames from the attached components such as
VMs or physical links.
+---------------------+ +-------+ +------+ +---------------------+ +-------+ +------+
| +--+ +-------+---+ | |Transit|--|Top of|==Physical | +--+ +-------+---+ | |Transit|--|Top of|==Physical
| |VM|--| | | | +------+ /|Router | | Rack |==Servers | |VM|--| | | | +------+ /|Router | | Rack |==Servers
| +--+ |Virtual|NIC|---|Top of|/ +-------+\/+------+ | +--+ |Virtual|NIC|---|Top of|/ +-------+\/+------+
| +--+ |Switch | | | | Rack |\ +-------+/\+------+ | +--+ |Switch | | | | Rack |\ +-------+/\+------+
| |VM|--| | | | +------+ \|Transit| |Uplink| WAN | |VM|--| | | | +------+ \|Transit| |Uplink| WAN
| +--+ +-------+---+ | |Router |--| |=========> | +--+ +-------+---+ | |Router |--| |=========>
+---------------------+ +-------+ +------+ +---------------------+ +-------+ +------+
Hypervisor Hypervisor
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o High performance over existing IP fabrics. o High performance over existing IP fabrics.
These requirements are described further in the following These requirements are described further in the following
subsections. subsections.
2.1. Control Plane Independence 2.1. Control Plane Independence
Although some protocols for network virtualization have included a Although some protocols for network virtualization have included a
control plane as part of the tunnel format specification (most control plane as part of the tunnel format specification (most
notably, the VXLAN spec prescribed a multicast learning- based notably, VXLAN [RFC7348] prescribed a multicast learning- based
control plane), these specifications have largely been treated as control plane), these specifications have largely been treated as
describing only the data format. The VXLAN packet format has describing only the data format. The VXLAN packet format has
actually seen a wide variety of control planes built on top of it. actually seen a wide variety of control planes built on top of it.
There is a clear advantage in settling on a data format: most of the There is a clear advantage in settling on a data format: most of the
protocols are only superficially different and there is little protocols are only superficially different and there is little
advantage in duplicating effort. However, the same cannot be said of advantage in duplicating effort. However, the same cannot be said of
control planes, which are diverse in very fundamental ways. The case control planes, which are diverse in very fundamental ways. The case
for standardization is also less clear given the wide variety in for standardization is also less clear given the wide variety in
requirements, goals, and deployment scenarios. requirements, goals, and deployment scenarios.
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finalized or retired. Options also allow for differentiation of finalized or retired. Options also allow for differentiation of
products by encouraging independent development in each vendor's core products by encouraging independent development in each vendor's core
specialty, leading to an overall faster pace of advancement. By far specialty, leading to an overall faster pace of advancement. By far
the most common mechanism for implementing options is Type-Length- the most common mechanism for implementing options is Type-Length-
Value (TLV) format. Value (TLV) format.
It should be noted that while options can be used to support non- It should be noted that while options can be used to support non-
wirespeed control packets, they are equally important on data packets wirespeed control packets, they are equally important on data packets
as well to segregate and direct forwarding (for instance, the as well to segregate and direct forwarding (for instance, the
examples given before of input port based security policies and examples given before of input port based security policies and
service interposition both require tags to be placed on data terminating/re-encapsulating service interposition both require tags
packets). Therefore, while it would be desirable to limit the to be placed on data packets). Therefore, while it would be
extensibility to only control packets for the purposes of simplifying desirable to limit the extensibility to only control packets for the
the datapath, that would not satisfy the design requirements. purposes of simplifying the datapath, that would not satisfy the
design requirements.
2.2.1. Efficient Implementation 2.2.1. Efficient Implementation
There is often a conflict between software flexibility and hardware There is often a conflict between software flexibility and hardware
performance that is difficult to resolve. For a given set of performance that is difficult to resolve. For a given set of
functionality, it is obviously desirable to maximize performance. functionality, it is obviously desirable to maximize performance.
However, that does not mean new features that cannot be run at a However, that does not mean new features that cannot be run at a
desired speed today should be disallowed. Therefore, for a protocol desired speed today should be disallowed. Therefore, for a protocol
to be efficiently implementable means that a set of common to be efficiently implementable means that a set of common
capabilities can be reasonably handled across platforms along with a capabilities can be reasonably handled across platforms along with a
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The use of a variable length header and options in a protocol often The use of a variable length header and options in a protocol often
raises questions about whether it is truly efficiently implementable raises questions about whether it is truly efficiently implementable
in hardware. To answer this question in the context of Geneve, it is in hardware. To answer this question in the context of Geneve, it is
important to first divide "hardware" into two categories: tunnel important to first divide "hardware" into two categories: tunnel
endpoints and transit devices. endpoints and transit devices.
Tunnel endpoints must be able to parse the variable header, including Tunnel endpoints must be able to parse the variable header, including
any options, and take action. Since these devices are actively any options, and take action. Since these devices are actively
participating in the protocol, they are the most affected by Geneve. participating in the protocol, they are the most affected by Geneve.
However, as tunnel endpoints are the ultimate consumers of the data, However, as tunnel endpoints are the ultimate consumers of the data,
transmitters can tailor their output to the capabilities of the transmitters can tailor their output to the capabilities of the
recipient. As new functionality becomes sufficiently well defined to recipient.
add to tunnel endpoints, supporting options can be designed using
ordering restrictions and other techniques to ease parsing.
Options, if present in the packet, MUST only be generated and Transit devices may be able to interpret the options, however, as
terminated by tunnel endpoints. Transit devices MAY be able to non-terminating devices, transit devices do not originate or
interpret the options, however, as non-terminating devices, transit terminate the Geneve packet, hence MUST NOT modify Geneve headers and
devices do not originate or terminate the Geneve packet, hence MUST MUST NOT insert or delete options, which is the responsibility of
NOT modify Geneve headers and MUST NOT insert or delete options, tunnel endpoints. Options, if present in the packet, MUST only be
which is the responsibility of tunnel endpoints. The participation generated and terminated by tunnel endpoints. The participation of
of transit devices in interpreting options is OPTIONAL. transit devices in interpreting options is OPTIONAL.
Further, either tunnel endpoints or transit devices MAY use offload Further, either tunnel endpoints or transit devices MAY use offload
capabilities of NICs such as checksum offload to improve the capabilities of NICs such as checksum offload to improve the
performance of Geneve packet processing. The presence of a Geneve performance of Geneve packet processing. The presence of a Geneve
variable length header SHOULD NOT prevent the tunnel endpoints and variable length header should not prevent the tunnel endpoints and
transit devices from using such offload capabilities. transit devices from using such offload capabilities.
2.3. Use of Standard IP Fabrics 2.3. Use of Standard IP Fabrics
IP has clearly cemented its place as the dominant transport mechanism IP has clearly cemented its place as the dominant transport mechanism
and many techniques have evolved over time to make it robust, and many techniques have evolved over time to make it robust,
efficient, and inexpensive. As a result, it is natural to use IP efficient, and inexpensive. As a result, it is natural to use IP
fabrics as a transit network for Geneve. Fortunately, the use of IP fabrics as a transit network for Geneve. Fortunately, the use of IP
encapsulation and addressing is enough to achieve the primary goal of encapsulation and addressing is enough to achieve the primary goal of
delivering packets to the correct point in the network through delivering packets to the correct point in the network through
skipping to change at page 10, line 15 skipping to change at page 10, line 28
| UDP Length | UDP Checksum | | UDP Length | UDP Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Geneve Header: Geneve Header:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Ver| Opt Len |O|C| Rsvd. | Protocol Type | |Ver| Opt Len |O|C| Rsvd. | Protocol Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Virtual Network Identifier (VNI) | Reserved | | Virtual Network Identifier (VNI) | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Variable Length Options | | Variable Length Options |
~ ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Inner Ethernet Header (example payload): Inner Ethernet Header (example payload):
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Inner Destination MAC Address | | Inner Destination MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Inner Destination MAC Address | Inner Source MAC Address | | Inner Destination MAC Address | Inner Source MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Inner Source MAC Address | | Inner Source MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Optional Ethertype=C-Tag 802.1Q| Inner VLAN Tag Information | |Optional Ethertype=C-Tag 802.1Q| Inner VLAN Tag Information |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Payload: Payload:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ethertype of Original Payload | | | Ethertype of Original Payload | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| Original Ethernet Payload | | Original Ethernet Payload |
| | | |
| (Note that the original Ethernet Frame's FCS is not included) | | (Note that the original Ethernet Frame's Preamble, Start Frame|
| Delimiter(SFD) & Frame Check Sequence(FCS) are not included |
| and the Ethernet Payload need not be 4-byte aligned) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Frame Check Sequence: Frame Check Sequence:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| New FCS (Frame Check Sequence) for Outer Ethernet Frame | | New Frame Check Sequence (FCS) for Outer Ethernet Frame |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.2. Geneve Packet Format Over IPv6 3.2. Geneve Packet Format Over IPv6
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
Outer Ethernet Header: Outer Ethernet Header:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Outer Destination MAC Address | | Outer Destination MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 11, line 48 skipping to change at page 12, line 18
| UDP Length | UDP Checksum | | UDP Length | UDP Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Geneve Header: Geneve Header:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Ver| Opt Len |O|C| Rsvd. | Protocol Type | |Ver| Opt Len |O|C| Rsvd. | Protocol Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Virtual Network Identifier (VNI) | Reserved | | Virtual Network Identifier (VNI) | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Variable Length Options | | Variable Length Options |
~ ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Inner Ethernet Header (example payload): Inner Ethernet Header (example payload):
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Inner Destination MAC Address | | Inner Destination MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Inner Destination MAC Address | Inner Source MAC Address | | Inner Destination MAC Address | Inner Source MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Inner Source MAC Address | | Inner Source MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Optional Ethertype=C-Tag 802.1Q| Inner VLAN Tag Information | |Optional Ethertype=C-Tag 802.1Q| Inner VLAN Tag Information |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Payload: Payload:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ethertype of Original Payload | | | Ethertype of Original Payload | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| Original Ethernet Payload | | Original Ethernet Payload |
| | | |
| (Note that the original Ethernet Frame's FCS is not included) | | (Note that the original Ethernet Frame's Preamble, Start Frame|
| Delimiter(SFD) & Frame Check Sequence(FCS) are not included |
| and the Ethernet Payload need not be 4-byte aligned) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Frame Check Sequence: Frame Check Sequence:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| New FCS (Frame Check Sequence) for Outer Ethernet Frame | | New Frame Check Sequence (FCS) for Outer Ethernet Frame |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.3. UDP Header 3.3. UDP Header
The use of an encapsulating UDP [RFC0768] header follows the The use of an encapsulating UDP [RFC0768] header follows the
connectionless semantics of Ethernet and IP in addition to providing connectionless semantics of Ethernet and IP in addition to providing
entropy to routers performing ECMP. The header fields are therefore entropy to routers performing ECMP. The header fields are therefore
interpreted as follows: interpreted as follows:
Source port: A source port selected by the originating tunnel Source port: A source port selected by the originating tunnel
endpoint. This source port SHOULD be the same for all packets endpoint. This source port SHOULD be the same for all packets
belonging to a single encapsulated flow to prevent reordering due belonging to a single encapsulated flow to prevent reordering due
to the use of different paths. To encourage an even distribution to the use of different paths. To encourage an even distribution
of flows across multiple links, the source port SHOULD be of flows across multiple links, the source port SHOULD be
calculated using a hash of the encapsulated packet headers using, calculated using a hash of the encapsulated packet headers using,
for example, a traditional 5-tuple. Since the port represents a for example, a traditional 5-tuple. Since the port represents a
flow identifier rather than a true UDP connection, the entire flow identifier rather than a true UDP connection, the entire
16-bit range MAY be used to maximize entropy. 16-bit range MAY be used to maximize entropy. In addition to
setting the source port, for IPv6, flow label MAY also be used for
providing entropy. For an example of using IPv6 flow label for
tunnel use cases, see [RFC6438].
If Geneve traffic is shared with other UDP listeners on the same
IP address, tunnel endpoints SHOULD implement a mechanism to
ensure ICMP return traffic arising from network errors is directed
to the correct listener. The definition of such a mechanism is
beyond the scope of this document.
Dest port: IANA has assigned port 6081 as the fixed well-known Dest port: IANA has assigned port 6081 as the fixed well-known
destination port for Geneve. Although the well-known value should destination port for Geneve. Although the well-known value should
be used by default, it is RECOMMENDED that implementations make be used by default, it is RECOMMENDED that implementations make
this configurable. The chosen port is used for identification of this configurable. The chosen port is used for identification of
Geneve packets and MUST NOT be reversed for different ends of a Geneve packets and MUST NOT be reversed for different ends of a
connection as is done with TCP. connection as is done with TCP. It is the responsibility of the
control plane for any reconfiguration of the assigned port and its
interpretation by respective devices. The definition of the
control plane is beyond the scope of this document.
UDP length: The length of the UDP packet including the UDP header. UDP length: The length of the UDP packet including the UDP header.
UDP checksum: In order to protect the Geneve header, options and UDP checksum: In order to protect the Geneve header, options and
payload from potential data corruption, UDP checksum SHOULD be payload from potential data corruption, UDP checksum SHOULD be
generated as specified in [RFC0768] and [RFC1112] when Geneve is generated as specified in [RFC0768] and [RFC1112] when Geneve is
encapsulated in IPv4. To protect the IP header, Geneve header, encapsulated in IPv4. To protect the IP header, Geneve header,
options and payload from potential data corruption, the UDP options and payload from potential data corruption, the UDP
checksum MUST be generated by default as specified in [RFC0768] checksum MUST be generated by default as specified in [RFC0768]
and [RFC2460] when Geneve is encapsulated in IPv6. Upon receiving and [RFC8200] when Geneve is encapsulated in IPv6, except for
such packets with non-zero UDP checksum, the receiving tunnel certain conditions, which are outlined in the next paragraph.
endpoints MUST validate the checksum. If the checksum is not Upon receiving such packets with non-zero UDP checksum, the
correct, the packet MUST be dropped, otherwise the packet MUST be receiving tunnel endpoints MUST validate the checksum. If the
accepted for decapsulation. checksum is not correct, the packet MUST be dropped, otherwise the
packet MUST be accepted for decapsulation.
Under certain conditions, the UDP checksum MAY be set to zero on Under certain conditions, the UDP checksum MAY be set to zero on
transmit for packets encapsulated in both IPv4 and IPv6 [RFC6935]. transmit for packets encapsulated in both IPv4 and IPv6 [RFC8200].
See Section 4.3 for additional requirements that apply for using See Section 4.3 for additional requirements that apply when using
zero UDP checksum with IPv4 and IPv6. Disabling the use of UDP zero UDP checksum with IPv4 and IPv6. Disabling the use of UDP
checksums is an operational consideration that should take into checksums is an operational consideration that should take into
account the risks and effects of packet corruption. account the risks and effects of packet corruption.
3.4. Tunnel Header Fields 3.4. Tunnel Header Fields
Ver (2 bits): The current version number is 0. Packets received by Ver (2 bits): The current version number is 0. Packets received by
a tunnel endpoint with an unknown version MUST be dropped. a tunnel endpoint with an unknown version MUST be dropped.
Transit devices interpreting Geneve packets with an unknown Transit devices interpreting Geneve packets with an unknown
version number MUST treat them as UDP packets with an unknown version number MUST treat them as UDP packets with an unknown
payload. payload.
Opt Len (6 bits): The length of the options fields, expressed in Opt Len (6 bits): The length of the options fields, expressed in
four byte multiples, not including the eight byte fixed tunnel four byte multiples, not including the eight byte fixed tunnel
header. This results in a minimum total Geneve header size of 8 header. This results in a minimum total Geneve header size of 8
bytes and a maximum of 260 bytes. The start of the payload bytes and a maximum of 260 bytes. The start of the payload
headers can be found using this offset from the end of the base headers can be found using this offset from the end of the base
Geneve header. Geneve header.
Transit devices MUST maintain consistent forwarding behavior
irrespective of the value of 'Opt Len', including ECMP link
selection.
O (1 bit): Control packet. This packet contains a control message. O (1 bit): Control packet. This packet contains a control message.
Control messages are sent between tunnel endpoints. Tunnel Control messages are sent between tunnel endpoints. Tunnel
Endpoints MUST NOT forward the payload and transit devices MUST endpoints MUST NOT forward the payload and transit devices MUST
NOT attempt to interpret it. Since these are infrequent control NOT attempt to interpret it. Since control messages are less
messages, it is RECOMMENDED that tunnel endpoints direct these frequent, it is RECOMMENDED that tunnel endpoints direct these
packets to a high priority control queue (for example, to direct packets to a high priority control queue (for example, to direct
the packet to a general purpose CPU from a forwarding ASIC or to the packet to a general purpose CPU from a forwarding ASIC or to
separate out control traffic on a NIC). Transit devices MUST NOT separate out control traffic on a NIC). Transit devices MUST NOT
alter forwarding behavior on the basis of this bit, such as ECMP alter forwarding behavior on the basis of this bit, such as ECMP
link selection. link selection.
C (1 bit): Critical options present. One or more options has the C (1 bit): Critical options present. One or more options has the
critical bit set (see Section 3.5). If this bit is set then critical bit set (see Section 3.5). If this bit is set then
tunnel endpoints MUST parse the options list to interpret any tunnel endpoints MUST parse the options list to interpret any
critical options. On tunnel endpoints where option parsing is not critical options. On tunnel endpoints where option parsing is not
supported the packet MUST be dropped on the basis of the 'C' bit supported the packet MUST be dropped on the basis of the 'C' bit
in the base header. If the bit is not set tunnel endpoints MAY in the base header. If the bit is not set tunnel endpoints MAY
strip all options using 'Opt Len' and forward the decapsulated strip all options using 'Opt Len' and forward the decapsulated
packet. Transit devices MUST NOT drop packets on the basis of packet. Transit devices MUST NOT drop packets on the basis of
this bit. this bit.
The critical bit allows hardware implementations the flexibility
to handle options processing in the hardware fastpath or in the
exception (slow) path without the need to process all the options.
For example, a critical option such as secure hash to provide
Geneve header integrity check must be processed by tunnel
endpoints and typically processed in the hardware fastpath.
Rsvd. (6 bits): Reserved field, which MUST be zero on transmission Rsvd. (6 bits): Reserved field, which MUST be zero on transmission
and MUST be ignored on receipt. and MUST be ignored on receipt.
Protocol Type (16 bits): The type of the protocol data unit Protocol Type (16 bits): The type of the protocol data unit
appearing after the Geneve header. This follows the EtherType appearing after the Geneve header. This follows the EtherType
[ETYPES] convention with Ethernet itself being represented by the [ETYPES] convention; with Ethernet itself being represented by the
value 0x6558. value 0x6558.
Virtual Network Identifier (VNI) (24 bits): An identifier for a Virtual Network Identifier (VNI) (24 bits): An identifier for a
unique element of a virtual network. In many situations this may unique element of a virtual network. In many situations this may
represent an L2 segment, however, the control plane defines the represent an L2 segment, however, the control plane defines the
forwarding semantics of decapsulated packets. The VNI MAY be used forwarding semantics of decapsulated packets. The VNI MAY be used
as part of ECMP forwarding decisions or MAY be used as a mechanism as part of ECMP forwarding decisions or MAY be used as a mechanism
to distinguish between overlapping address spaces contained in the to distinguish between overlapping address spaces contained in the
encapsulated packet when load balancing across CPUs. encapsulated packet when load balancing across CPUs.
Reserved (8 bits): Reserved field which MUST be zero on transmission Reserved (8 bits): Reserved field which MUST be zero on transmission
and ignored on receipt. and ignored on receipt.
Transit devices MUST maintain consistent forwarding behavior
irrespective of the value of 'Opt Len', including ECMP link
selection. These devices SHOULD be able to forward packets
containing options without resorting to a slow path.
3.5. Tunnel Options 3.5. Tunnel Options
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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
| Option Class | Type |R|R|R| Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option Class | Type |R|R|R| Length |
| Variable Option Data | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Variable Option Data |
~ ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Geneve Option Geneve Option
The base Geneve header is followed by zero or more options in Type- The base Geneve header is followed by zero or more options in Type-
Length-Value format. Each option consists of a four byte option Length-Value format. Each option consists of a four byte option
header and a variable amount of option data interpreted according to header and a variable amount of option data interpreted according to
the type. the type.
Option Class (16 bits): Namespace for the 'Type' field. IANA will Option Class (16 bits): Namespace for the 'Type' field. IANA will
be requested to create a "Geneve Option Class" registry to be requested to create a "Geneve Option Class" registry to
allocate identifiers for organizations, technologies, and vendors allocate identifiers for organizations, technologies, and vendors
that have an interest in creating types for options. Each that have an interest in creating types for options. Each
organization may allocate types independently to allow organization may allocate types independently to allow
experimentation and rapid innovation. It is expected that over experimentation and rapid innovation. It is expected that over
time certain options will become well known and a given time certain options will become well known and a given
implementation may use option types from a variety of sources. In implementation may use option types from a variety of sources. In
addition, IANA will be requested to reserve specific ranges for addition, IANA will be requested to reserve specific ranges for
standardized and experimental options. allocation by IETF Review and for Experimental Use (see
Section 7).
Type (8 bits): Type indicating the format of the data contained in Type (8 bits): Type indicating the format of the data contained in
this option. Options are primarily designed to encourage future this option. Options are primarily designed to encourage future
extensibility and innovation and so standardized forms of these extensibility and innovation and so standardized forms of these
options will be defined in a separate document. options will be defined in separate documents.
The high order bit of the option type indicates that this is a The high order bit of the option type indicates that this is a
critical option. If the receiving tunnel endpoint does not critical option. If the receiving tunnel endpoint does not
recognize this option and this bit is set then the packet MUST be recognize this option and this bit is set then the packet MUST be
dropped. If the 'C' bit (critical bit) is set in any option then dropped. If this bit is set in any option then the 'C' bit in the
the 'C' bit in the Geneve base header MUST also be set. Transit Geneve base header MUST also be set. Transit devices MUST NOT
devices MUST NOT drop packets on the basis of this bit. The drop packets on the basis of this bit. The following figure shows
following figure shows the location of the 'C' bit in the 'Type' the location of the 'C' bit in the 'Type' field:
field:
0 1 2 3 4 5 6 7 8 0 1 2 3 4 5 6 7 8
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|C| Type | |C| Type |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
The requirement to drop a packet with an unknown option with the The requirement to drop a packet with an unknown option with the
'C' bit set applies to the entire tunnel endpoint system and not a 'C' bit set applies to the entire tunnel endpoint system and not a
particular component of the implementation. For example, in a particular component of the implementation. For example, in a
system comprised of a forwarding ASIC and a general purpose CPU, system comprised of a forwarding ASIC and a general purpose CPU,
this does not mean that the packet must be dropped in the ASIC. this does not mean that the packet must be dropped in the ASIC.
An implementation may send the packet to the CPU using a rate- An implementation may send the packet to the CPU using a rate-
limited control channel for slow-path exception handling. limited control channel for slow-path exception handling.
R (3 bits): Option control flags reserved for future use. MUST be R (3 bits): Option control flags reserved for future use. These
zero on transmission and ignored on receipt. bits MUST be zero on transmission and MUST be ignored on receipt.
Length (5 bits): Length of the option, expressed in four byte Length (5 bits): Length of the option, expressed in four byte
multiples excluding the option header. The total length of each multiples excluding the option header. The total length of each
option may be between 4 and 128 bytes. A value of 0 in the Length option may be between 4 and 128 bytes. A value of 0 in the Length
field implies an option with only the option header without the field implies an option with only an option header and no variable
variable option data. Packets in which the total length of all option data. Packets in which the total length of all options is
options is not equal to the 'Opt Len' in the base header are not equal to the 'Opt Len' in the base header are invalid and MUST
invalid and MUST be silently dropped if received by a tunnel be silently dropped if received by a tunnel endpoint that
endpoint that processes the options. processes the options.
Variable Option Data: Option data interpreted according to 'Type'. Variable Option Data: Option data interpreted according to 'Type'.
3.5.1. Options Processing 3.5.1. Options Processing
Geneve options are intended to be originated and processed by tunnel Geneve options are intended to be originated and processed by tunnel
endpoints. However, options MAY be interpreted by transit devices endpoints. However, options MAY be interpreted by transit devices
along the tunnel path. Transit devices not interpreting Geneve along the tunnel path. Transit devices not interpreting Geneve
headers (that may or may not include options) MUST handle Geneve headers (which may or may not include options) MUST handle Geneve
packets as any other UDP packet and maintain consistent forwarding packets as any other UDP packet and maintain consistent forwarding
behavior. behavior.
In tunnel endpoints, the generation and interpretation of options is In tunnel endpoints, the generation and interpretation of options is
determined by the control plane, which is out of the scope of this determined by the control plane, which is beyond the the scope of
document. However, to ensure interoperability between heterogeneous this document. However, to ensure interoperability between
devices some requirements are imposed on options and the devices that heterogeneous devices some requirements are imposed on options and
process them: the devices that process them:
o Receiving tunnel endpoints MUST drop packets containing unknown o Receiving tunnel endpoints MUST drop packets containing unknown
options with the 'C' bit set in the option type. Conversely, options with the 'C' bit set in the option type. Conversely,
transit devices MUST NOT drop packets as a result of encountering transit devices MUST NOT drop packets as a result of encountering
unknown options, including those with the 'C' bit set. unknown options, including those with the 'C' bit set.
o Some options may be defined in such a way that the position in the o The contents of the options and their ordering MUST NOT be
option list is significant. Options MUST NOT be changed by modified by transit devices.
transit devices.
o An option SHOULD NOT be dependent upon any other option in the o If a tunnel endpoint receives a Geneve packet with 'Opt Len'
packet, i.e., options can be processed independently of one (total length of all options) that exceeds the options processing
another. Architecturally, options are intended to be self- capability of the tunnel endpoint then the tunnel endpoint MUST
descriptive and independent. This enables parallelism in option drop such packets. An implementation may raise an exception to
processing and reduces implementation complexity. the control plane of such an event. It is the responsibility of
the control plane to ensure the communicating peer tunnel
endpoints have the processing capability to handle the total
length of options. The definition of the control plane is beyond
the scope of this document.
When designing a Geneve option, it is important to consider how the When designing a Geneve option, it is important to consider how the
option will evolve in the future. Once an option is defined it is option will evolve in the future. Once an option is defined it is
reasonable to expect that implementations may come to depend on a reasonable to expect that implementations may come to depend on a
specific behavior. As a result, the scope of any future changes must specific behavior. As a result, the scope of any future changes must
be carefully described upfront. be carefully described upfront.
Architecturally, options are intended to be self-descriptive and
independent. This enables parallelism in option processing and
reduces implementation complexity. However, the control plane may
impose certain ordering restrictions as described in Section 4.5.1.
Unexpectedly significant interoperability issues may result from Unexpectedly significant interoperability issues may result from
changing the length of an option that was defined to be a certain changing the length of an option that was defined to be a certain
size. A particular option is specified to have either a fixed size. A particular option is specified to have either a fixed
length, which is constant, or a variable length, which may change length, which is constant, or a variable length, which may change
over time or for different use cases. This property is part of the over time or for different use cases. This property is part of the
definition of the option and conveyed by the 'Type'. For fixed definition of the option and conveyed by the 'Type'. For fixed
length options, some implementations may choose to ignore the length length options, some implementations may choose to ignore the length
field in the option header and instead parse based on the well known field in the option header and instead parse based on the well known
length associated with the type. In this case, redefining the length length associated with the type. In this case, redefining the length
will impact not only parsing of the option in question but also any will impact not only parsing of the option in question but also any
options that follow. Therefore, options that are defined to be fixed options that follow. Therefore, options that are defined to be fixed
length in size MUST NOT be redefined to a different length. Instead, length in size MUST NOT be redefined to a different length. Instead,
a new 'Type' should be allocated. a new 'Type' should be allocated. Actual definition of the option
type is beyond the scope of this document. The option type and its
interpretation should be defined by the entity that owns the option
class.
Options may be processed by NIC hardware utilizing offloads (e.g. Options may be processed by NIC hardware utilizing offloads (e.g.
LSO and LRO) as described in Section 4.6. Careful consideration LSO and LRO) as described in Section 4.6. Careful consideration
should be given to how the offload capabilities outlined in should be given to how the offload capabilities outlined in
Section 4.6 impact an option's design. Section 4.6 impact an option's design.
4. Implementation and Deployment Considerations 4. Implementation and Deployment Considerations
4.1. Applicability Statement 4.1. Applicability Statement
skipping to change at page 17, line 49 skipping to change at page 18, line 39
environments, for deploying multi-tenant overlay networks over an environments, for deploying multi-tenant overlay networks over an
existing IP underlay network. existing IP underlay network.
Geneve is a UDP based encapsulation protocol transported over Geneve is a UDP based encapsulation protocol transported over
existing IPv4 and IPv6 networks. Hence, as a UDP based protocol, existing IPv4 and IPv6 networks. Hence, as a UDP based protocol,
Geneve adheres to the UDP usage guidelines as specified in [RFC8085]. Geneve adheres to the UDP usage guidelines as specified in [RFC8085].
The applicability of these guidelines are dependent on the underlay The applicability of these guidelines are dependent on the underlay
IP network and the nature of Geneve payload protocol (example TCP/IP, IP network and the nature of Geneve payload protocol (example TCP/IP,
IP/Ethernet). IP/Ethernet).
[RFC8085] outlines two applicability scenarios for UDP applications,
1) general Internet and 2) controlled environment. The controlled
environment means a single administrative domain or adjacent set of
cooperating domains. A network in a controlled environment can be
managed to operate under certain conditions whereas in general
Internet this cannot be done. Hence requirements for a tunnel
protocol operating under a controlled environment can be less
restrictive than the requirements of general internet.
Geneve is intended to be deployed in a data center network Geneve is intended to be deployed in a data center network
environment operated by a single operator or adjacent set of environment operated by a single operator or adjacent set of
cooperating network operators that fits with the definition of cooperating network operators that fits with the definition of
controlled environments in [RFC8085]. controlled environments in [RFC8085]. A network in a controlled
environment can be managed to operate under certain conditions
whereas in the general Internet this cannot be done. Hence
requirements for a tunnel protocol operating under a controlled
environment can be less restrictive than the requirements of the
general Internet.
For the purpose of this document, a traffic-managed controlled For the purpose of this document, a traffic-managed controlled
environment (TMCE) is defined as an IP network that is traffic- environment (TMCE) is defined as an IP network that is traffic-
engineered and/or otherwise managed (e.g., via use of traffic rate engineered and/or otherwise managed (e.g., via use of traffic rate
limiters) to avoid congestion. The concept of TMCE is outlined in limiters) to avoid congestion. The concept of TMCE is outlined in
[RFC8086]. Significant portions of text in Section 4.1 through [RFC8086]. Significant portions of the text in Section 4.1 through
Section 4.3 are based on [RFC8086] as applicable to Geneve. Section 4.3 are based on [RFC8086] as applicable to Geneve.
It is the responsibility of the operator to ensure that the It is the responsibility of the operator to ensure that the
guidelines/requirements in this section are followed as applicable to guidelines/requirements in this section are followed as applicable to
their Geneve deployment(s). their Geneve deployment(s).
4.2. Congestion Control Functionality 4.2. Congestion Control Functionality
Geneve does not natively provide congestion control functionality and Geneve does not natively provide congestion control functionality and
relies on the payload protocol traffic for congestion control. As relies on the payload protocol traffic for congestion control. As
such Geneve MUST be used with congestion controlled traffic or within such Geneve MUST be used with congestion controlled traffic or within
a network that is traffic managed to avoid congestion (TMCE). An a network that is traffic managed to avoid congestion (TMCE). An
operator of a traffic managed network (TMCE) may avoid congestion by operator of a traffic managed network (TMCE) may avoid congestion by
careful provisioning of their networks, rate-limiting of user data careful provisioning of their networks, rate-limiting of user data
traffic and traffic engineering according to path capacity. traffic and traffic engineering according to path capacity.
4.3. UDP Checksum 4.3. UDP Checksum
In order to provide integrity of Geneve headers, options and payload, In order to provide integrity of Geneve headers, options and payload,
for example to avoid mis-delivery of payload to different tenant (for example to avoid misdelivery of payload to different tenant
systems in case of data corruption, outer UDP checksum SHOULD be used systems) in case of data corruption, the outer UDP checksum SHOULD be
with Geneve when transported over IPv4. The UDP checksum provides a used with Geneve when transported over IPv4. The UDP checksum
statistical guarantee that a payload was not corrupted in transit. provides a statistical guarantee that a payload was not corrupted in
These integrity checks are not strong from a coding or cryptographic transit. These integrity checks are not strong from a coding or
perspective and are not designed to detect physical-layer errors or cryptographic perspective and are not designed to detect physical-
malicious modification of the datagram (see Section 3.4 of layer errors or malicious modification of the datagram (see
[RFC8085]). In deployments where such a risk exists, an operator Section 3.4 of [RFC8085]). In deployments where such a risk exists,
SHOULD use additional data integrity mechanisms such as offered by an operator SHOULD use additional data integrity mechanisms such as
IPSec (see Section 6.2). offered by IPsec (see Section 6.2).
An operator MAY choose to disable UDP checksum and use zero checksum An operator MAY choose to disable UDP checksums and use zero
if Geneve packet integrity is provided by other data integrity checksums if Geneve packet integrity is provided by other data
mechanisms such as IPsec or additional checksums or if one of the integrity mechanisms such as IPsec or additional checksums or if one
conditions in Section 4.3.1 a, b, c are met. of the conditions in Section 4.3.1 a, b, c are met.
By default, UDP checksum MUST be used when Geneve is transported over By default, UDP checksums MUST be used when Geneve is transported
IPv6. A tunnel endpoint MAY be configured for use with zero UDP over IPv6. A tunnel endpoint MAY be configured for use with zero UDP
checksum if additional requirements in Section 4.3.1 are met. checksum if additional requirements in Section 4.3.1 are met.
4.3.1. UDP Zero Checksum Handling with IPv6 4.3.1. UDP Zero Checksum Handling with IPv6
When Geneve is used over IPv6, UDP checksum is used to protect IPv6 When Geneve is used over IPv6, the UDP checksum is used to protect
headers, UDP headers and Geneve headers, options and payload from IPv6 headers, UDP headers and Geneve headers, options and payload
potential data corruption. As such by default Geneve MUST use UDP from potential data corruption. As such by default Geneve MUST use
checksum when transported over IPv6. An operator MAY choose to UDP checksums when transported over IPv6. An operator MAY choose to
configure to operate with zero UDP checksum if operating in a traffic configure to operate with zero UDP checksum if operating in a traffic
managed controlled environment as stated in Section 4.1 if one of the managed controlled environment as stated in Section 4.1 if one of the
following conditions are met. following conditions are met.
a. It is known that the packet corruption is exceptionally unlikely a. It is known that the packet corruption is exceptionally unlikely
(perhaps based on knowledge of equipment types in their underlay (perhaps based on knowledge of equipment types in their underlay
network) and the operator is willing to take a risk of undetected network) and the operator is willing to take a risk of undetected
packet corruption packet corruption
b. It is judged through observational measurements (perhaps through b. It is judged through observational measurements (perhaps through
historic or current traffic flows that use non zero checksum) historic or current traffic flows that use non zero checksum)
that the level of packet corruption is tolerably low and where that the level of packet corruption is tolerably low and where
the operator is willing to take the risk of undetected the operator is willing to take the risk of undetected
corruption. corruption.
c. Geneve payload is carrying applications that are tolerant of c. Geneve payload is carrying applications that are tolerant of
misdelivered or corrupted packets (perhaps through higher layer misdelivered or corrupted packets (perhaps through higher layer
checksum validation and/or reliability through retransmission) checksum validation and/or reliability through retransmission)
In addition Geneve tunnel implementations using Zero UDP checksum In addition Geneve tunnel implementations using zero UDP checksum
MUST meet the following requirements: MUST meet the following requirements:
1. Use of UDP checksum over IPv6 MUST be the default configuration 1. Use of UDP checksum over IPv6 MUST be the default configuration
for all Geneve tunnels. for all Geneve tunnels.
2. If Geneve is used with zero UDP checksum over IPv6 then such 2. If Geneve is used with zero UDP checksum over IPv6 then such
tunnel endpoint implementation MUST meet all the requirements tunnel endpoint implementation MUST meet all the requirements
specified in section 4 of [RFC6936] and requirements 1 as specified in Section 4 of [RFC6936] and requirement 1 as
specified in section 5 of [RFC6936]. specified in Section 5 of [RFC6936] as that is relevant to
Geneve.
3. The Geneve tunnel endpoint that decapsulates the tunnel SHOULD 3. The Geneve tunnel endpoint that decapsulates the tunnel SHOULD
check the source and destination IPv6 addresses are valid for the check the source and destination IPv6 addresses are valid for the
Geneve tunnel that is configured to receive Zero UDP checksum and Geneve tunnel that is configured to receive zero UDP checksum and
discard other packets for which such check fails. discard other packets for which such check fails.
4. The Geneve tunnel endpoint that encapsulates the tunnel MAY use 4. The Geneve tunnel endpoint that encapsulates the tunnel MAY use
different IPv6 source addresses for each Geneve tunnel that uses different IPv6 source addresses for each Geneve tunnel that uses
Zero UDP checksum mode in order to strengthen the decapsulator's zero UDP checksum mode in order to strengthen the decapsulator's
check of the IPv6 source address (i.e the same IPv6 source check of the IPv6 source address (i.e the same IPv6 source
address is not to be used with more than one IPv6 destination address is not to be used with more than one IPv6 destination
address, irrespective of whether that destination address is a address, irrespective of whether that destination address is a
unicast or multicast address). When this is not possible, it is unicast or multicast address). When this is not possible, it is
RECOMMENDED to use each source address for as few Geneve tunnels RECOMMENDED to use each source address for as few Geneve tunnels
that use zero UDP checksum as is feasible. that use zero UDP checksum as is feasible.
Note that (for requirements 3 and 4) the receiving tunnel
endpoint can apply these checks only if it has out-of-band
knowledge that the encapsulating tunnel endpoint is applying the
indicated behavior. One possibility to obtain this out-of-band
knowledge is through signaling by the control plane. The
definition of the control plane is beyond the scope of this
document.
5. Measures SHOULD be taken to prevent Geneve traffic over IPv6 with 5. Measures SHOULD be taken to prevent Geneve traffic over IPv6 with
zero UDP checksum from escaping into the general Internet. zero UDP checksum from escaping into the general Internet.
Examples of such measures include employing packet filters at the Examples of such measures include employing packet filters at the
Gateways or edge of Geneve network and/or keeping logical or gateways or edge of Geneve network and/or keeping logical or
physical separation of Geneve network from networks carrying physical separation of the Geneve network from networks carrying
General Internet. the general Internet traffic.
The above requirements do not change either the requirements The above requirements do not change either the requirements
specified in [RFC2460] as modified by [RFC6935] or the requirements specified in [RFC8200] or the requirements specified in [RFC6936].
specified in [RFC6936].
The requirement to check the source IPv6 address in addition to the The use of the source IPv6 address in addition to the destination
destination IPv6 address, plus the recommendation against reuse of IPv6 address, plus the recommendation against reuse of source IPv6
source IPv6 addresses among Geneve tunnels collectively provide some addresses among Geneve tunnels collectively provide some mitigation
mitigation for the absence of UDP checksum coverage of the IPv6 for the absence of UDP checksum coverage of the IPv6 header. A
header. A traffic-managed controlled environment that satisfies at traffic-managed controlled environment that satisfies at least one of
least one of three conditions listed at the beginning of this section three conditions listed at the beginning of this section provides
provides additional assurance. additional assurance.
Editorial Note (The following paragraph to be removed by the RFC Editorial Note (The following paragraph to be removed by the RFC
Editor before publication) Editor before publication)
It was discussed during TSVART early review if the level of It was discussed during TSVART early review if the level of
requirement for using different IPv6 source addresses for different requirement for using different IPv6 source addresses for different
tunnel destinations would need to be "MAY" or "SHOULD". The tunnel destinations would need to be "MAY" or "SHOULD". The
discussion concluded that it was appropriate to keep this as "MAY", discussion concluded that it was appropriate to keep this as "MAY",
since it was considered not realistic for control planes having to since it was considered not realistic for control planes having to
maintain a high level of state on a per tunnel destination basis. In maintain a high level of state on a per tunnel destination basis. In
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As an IP-based tunnel protocol, Geneve shares many properties and As an IP-based tunnel protocol, Geneve shares many properties and
techniques with existing protocols. The application of some of these techniques with existing protocols. The application of some of these
are described in further detail, although in general most concepts are described in further detail, although in general most concepts
applicable to the IP layer or to IP tunnels generally also function applicable to the IP layer or to IP tunnels generally also function
in the context of Geneve. in the context of Geneve.
4.4.1. IP Fragmentation 4.4.1. IP Fragmentation
It is strongly RECOMMENDED that Path MTU Discovery ([RFC1191], It is strongly RECOMMENDED that Path MTU Discovery ([RFC1191],
[RFC8201]) be used by setting the DF bit in the IP header when Geneve [RFC8201]) be used to prevent or minimize fragmentation. The use of
packets are transmitted over IPv4 (this is the default with IPv6). Path MTU Discovery on the transit network provides the encapsulating
The use of Path MTU Discovery on the transit network provides the tunnel endpoint with soft-state about the link that it may use to
encapsulating tunnel endpoint with soft-state about the link that it prevent or minimize fragmentation depending on its role in the
may use to prevent or minimize fragmentation depending on its role in virtualized network. The NVE can maintain this state (the MTU size
the virtualized network. The NVE control plane MAY use configuration of the tunnel link(s) associated with the tunnel endpoint), so if a
mechanism or path discovery information to maintain the MTU size of
the tunnel link(s) associated with the tunnel endpoint, so if a
tenant system sends large packets that when encapsulated exceed the tenant system sends large packets that when encapsulated exceed the
MTU size of the tunnel link, the tunnel endpoint can discard such MTU size of the tunnel link, the tunnel endpoint can discard such
packets and send exception messages to the tenant system(s). If the packets and send exception messages to the tenant system(s). If the
tunnel endpoint is associated with a routing or forwarding function tunnel endpoint is associated with a routing or forwarding function
and/or has the capability to send ICMP messages, the encapsulating and/or has the capability to send ICMP messages, the encapsulating
tunnel endpoint MAY send ICMP fragmentation needed [RFC0792] or tunnel endpoint MAY send ICMP fragmentation needed [RFC0792] or
Packet Too Big [RFC4443] messages to the tenant system(s). For Packet Too Big [RFC4443] messages to the tenant system(s). When
determining the MTU size of a tunnel link, maximum length of options
MUST be assumed as options may vary on a per-packet basis. For
example, recommendations/guidance for handling fragmentation in example, recommendations/guidance for handling fragmentation in
similar overlay encapsulation services like PWE3 are provided in similar overlay encapsulation services like PWE3 are provided in
section 5.3 of [RFC3985]. Section 5.3 of [RFC3985].
Note that some implementations may not be capable of supporting Note that some implementations may not be capable of supporting
fragmentation or other less common features of the IP header, such as fragmentation or other less common features of the IP header, such as
options and extension headers. For example, some of the issues options and extension headers. For example, some of the issues
associated with MTU size and fragmentation in IP tunneling and use of associated with MTU size and fragmentation in IP tunneling and use of
ICMP messages is outlined in section 4.2 of ICMP messages is outlined in Section 4.2 of
[I-D.ietf-intarea-tunnels]. [I-D.ietf-intarea-tunnels].
Editorial Note (The following paragraph to be removed by the RFC
Editor before publication)
It was discussed during TSVART early review if the level of
requirement for maintaining tunnel MTU at the ingress has to be "MAY"
or "SHOULD". The discussion concluded that it was appropriate to
leave this as "MAY", considering the high level of state to be
maintained.
4.4.2. DSCP, ECN and TTL 4.4.2. DSCP, ECN and TTL
When encapsulating IP (including over Ethernet) packets in Geneve, When encapsulating IP (including over Ethernet) packets in Geneve,
there are several considerations for propagating DSCP and ECN bits there are several considerations for propagating DSCP and ECN bits
from the inner header to the tunnel on transmission and the reverse from the inner header to the tunnel on transmission and the reverse
on reception. on reception.
[RFC2983] provides guidance for mapping DSCP between inner and outer [RFC2983] provides guidance for mapping DSCP between inner and outer
IP headers. Network virtualization is typically more closely aligned IP headers. Network virtualization is typically more closely aligned
with the Pipe model described, where the DSCP value on the tunnel with the Pipe model described, where the DSCP value on the tunnel
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header on tunnel egress based on transit marking. However, the header on tunnel egress based on transit marking. However, the
Uniform model is not conceptually consistent with network Uniform model is not conceptually consistent with network
virtualization, which seeks to provide strong isolation between virtualization, which seeks to provide strong isolation between
encapsulated traffic and the physical network. encapsulated traffic and the physical network.
[RFC6040] describes the mechanism for exposing ECN capabilities on IP [RFC6040] describes the mechanism for exposing ECN capabilities on IP
tunnels and propagating congestion markers to the inner packets. tunnels and propagating congestion markers to the inner packets.
This behavior MUST be followed for IP packets encapsulated in Geneve. This behavior MUST be followed for IP packets encapsulated in Geneve.
Though Uniform or Pipe models could be used for TTL (or Hop Limit in Though Uniform or Pipe models could be used for TTL (or Hop Limit in
case of IPv6) handling when tunneling IP packets, Pipe model is more case of IPv6) handling when tunneling IP packets, the Pipe model is
aligned with network virtualization. [RFC2003] provides guidance on more aligned with network virtualization. [RFC2003] provides
handling TTL between inner IP header and outer IP tunnels; this model guidance on handling TTL between inner IP header and outer IP
is more aligned with the Pipe model and is recommended for use with tunnels; this model is more aligned with the Pipe model and is
Geneve for network virtualization applications. RECOMMENDED for use with Geneve for network virtualization
applications.
4.4.3. Broadcast and Multicast 4.4.3. Broadcast and Multicast
Geneve tunnels may either be point-to-point unicast between two Geneve tunnels may either be point-to-point unicast between two
tunnel endpoints or may utilize broadcast or multicast addressing. tunnel endpoints or may utilize broadcast or multicast addressing.
It is not required that inner and outer addressing match in this It is not required that inner and outer addressing match in this
respect. For example, in physical networks that do not support respect. For example, in physical networks that do not support
multicast, encapsulated multicast traffic may be replicated into multicast, encapsulated multicast traffic may be replicated into
multiple unicast tunnels or forwarded by policy to a unicast location multiple unicast tunnels or forwarded by policy to a unicast location
(possibly to be replicated there). (possibly to be replicated there).
With physical networks that do support multicast it may be desirable With physical networks that do support multicast it may be desirable
to use this capability to take advantage of hardware replication for to use this capability to take advantage of hardware replication for
encapsulated packets. In this case, multicast addresses may be encapsulated packets. In this case, multicast addresses may be
allocated in the physical network corresponding to tenants, allocated in the physical network corresponding to tenants,
encapsulated multicast groups, or some other factor. The allocation encapsulated multicast groups, or some other factor. The allocation
of these groups is a component of the control plane and therefore of these groups is a component of the control plane and therefore is
outside of the scope of this document. When physical multicast is in beyond the scope of this document.
use, the 'C' bit in the Geneve header may be used with groups of
devices with heterogeneous capabilities as each device can interpret When physical multicast is in use, devices with heterogeneous
only the options that are significant to it if they are not critical. capabilities may be present in the same group. Some options may only
be interpretable by a subset of the devices in the group. Other
devices can safely ignore such options unless the 'C' bit is set to
mark the unknown option as critical. Requirements outlined in
Section 3.4 apply for critical options.
In addition, [RFC8293] provides examples of various mechanisms that In addition, [RFC8293] provides examples of various mechanisms that
can be used for multicast handling in network virtualization overlay can be used for multicast handling in network virtualization overlay
networks. networks.
4.4.4. Unidirectional Tunnels 4.4.4. Unidirectional Tunnels
Generally speaking, a Geneve tunnel is a unidirectional concept. IP Generally speaking, a Geneve tunnel is a unidirectional concept. IP
is not a connection oriented protocol and it is possible for two is not a connection oriented protocol and it is possible for two
tunnel endpoints to communicate with each other using different paths tunnel endpoints to communicate with each other using different paths
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optimize for a particular use case. For example, some applications optimize for a particular use case. For example, some applications
may limit the types of options which are supported or enforce a may limit the types of options which are supported or enforce a
maximum number or length of options. Other applications may only maximum number or length of options. Other applications may only
handle certain encapsulated payload types, such as Ethernet or IP. handle certain encapsulated payload types, such as Ethernet or IP.
This could be either globally throughout the system or, for example, This could be either globally throughout the system or, for example,
restricted to certain classes of devices or network paths. restricted to certain classes of devices or network paths.
These constraints may be communicated to tunnel endpoints either These constraints may be communicated to tunnel endpoints either
explicitly through a control plane or implicitly by the nature of the explicitly through a control plane or implicitly by the nature of the
application. As Geneve is defined as a data plane protocol that is application. As Geneve is defined as a data plane protocol that is
control plane agnostic, the exact mechanism is not defined in this control plane agnostic, definition of such mechanisms are beyond the
document. scope of this document.
4.5.1. Constraints on Options 4.5.1. Constraints on Options
While Geneve options are more flexible, a control plane may restrict While Geneve options are flexible, a control plane may restrict the
the number of option TLVs as well as the order and size of the TLVs, number of option TLVs as well as the order and size of the TLVs
between tunnel endpoints, to make it simpler for a data plane between tunnel endpoints to make it simpler for a data plane
implementation in software or hardware to handle implementation in software or hardware to handle
[I-D.ietf-nvo3-encap]. For example, there may be some critical [I-D.ietf-nvo3-encap]. For example, there may be some critical
information such as a secure hash that must be processed in a certain information such as a secure hash that must be processed in a certain
order to provide lowest latency. order to provide lowest latency or there may be other scenarios where
the options must be processed in a certain order due to protocol
semantics.
A control plane may negotiate a subset of option TLVs and certain TLV A control plane may negotiate a subset of option TLVs and certain TLV
ordering, as well may limit the total number of option TLVs present ordering, as well may limit the total number of option TLVs present
in the packet, for example, to accommodate hardware capable of in the packet, for example, to accommodate hardware capable of
processing fewer options [I-D.ietf-nvo3-encap]. Hence, a control processing fewer options [I-D.ietf-nvo3-encap]. Hence, a control
plane needs to have the ability to describe the supported TLVs subset plane needs to have the ability to describe the supported TLVs subset
and their order to the tunnel endpoints. In the absence of a control and their order to the tunnel endpoints. In the absence of a control
plane, alternative configuration mechanisms may be used for this plane, alternative configuration mechanisms may be used for this
purpose. The exact mechanism is not defined in this document. purpose. Such mechanisms are beyond the scope of this document.
4.6. NIC Offloads 4.6. NIC Offloads
Modern NICs currently provide a variety of offloads to enable the Modern NICs currently provide a variety of offloads to enable the
efficient processing of packets. The implementation of many of these efficient processing of packets. The implementation of many of these
offloads requires only that the encapsulated packet be easily parsed offloads requires only that the encapsulated packet be easily parsed
(for example, checksum offload). However, optimizations such as LSO (for example, checksum offload). However, optimizations such as LSO
and LRO involve some processing of the options themselves since they and LRO involve some processing of the options themselves since they
must be replicated/merged across multiple packets. In these must be replicated/merged across multiple packets. In these
situations, it is desirable to not require changes to the offload situations, it is desirable to not require changes to the offload
logic to handle the introduction of new options. To enable this, logic to handle the introduction of new options. To enable this,
some constraints are placed on the definitions of options to allow some constraints are placed on the definitions of options to allow
for simple processing rules: for simple processing rules:
o When performing LSO, a NIC MUST replicate the entire Geneve header o When performing LSO, a NIC MUST replicate the entire Geneve header
and all options, including those unknown to the device, onto each and all options, including those unknown to the device, onto each
resulting segment. However, a given option definition may resulting segment unless an option allows an exception.
override this rule and specify different behavior in supporting Conversely, when performing LRO, a NIC may assume that a binary
devices. Conversely, when performing LRO, a NIC MAY assume that a comparison of the options (including unknown options) is
binary comparison of the options (including unknown options) is
sufficient to ensure equality and MAY merge packets with equal sufficient to ensure equality and MAY merge packets with equal
Geneve headers. Geneve headers.
o Options MUST NOT be reordered during the course of offload o Options MUST NOT be reordered during the course of offload
processing, including when merging packets for the purpose of LRO. processing, including when merging packets for the purpose of LRO.
o NICs performing offloads MUST NOT drop packets with unknown o NICs performing offloads MUST NOT drop packets with unknown
options, including those marked as critical, unless explicitly options, including those marked as critical, unless explicitly
configured. configured.
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As with any protocol, support for inner VLAN headers is OPTIONAL. In As with any protocol, support for inner VLAN headers is OPTIONAL. In
many cases, the use of encapsulated VLANs may be disallowed due to many cases, the use of encapsulated VLANs may be disallowed due to
security or implementation considerations. However, in other cases security or implementation considerations. However, in other cases
trunking of VLAN frames across a Geneve tunnel can prove useful. As trunking of VLAN frames across a Geneve tunnel can prove useful. As
a result, the processing of inner VLAN tags upon ingress or egress a result, the processing of inner VLAN tags upon ingress or egress
from a tunnel endpoint is based upon the configuration of the tunnel from a tunnel endpoint is based upon the configuration of the tunnel
endpoint and/or control plane and not explicitly defined as part of endpoint and/or control plane and not explicitly defined as part of
the data format. the data format.
5. Interoperability Issues 5. Transition Considerations
Viewed exclusively from the data plane, Geneve does not introduce any Viewed exclusively from the data plane, Geneve is compatible with
interoperability issues as it appears to most devices as UDP packets. existing IP networks as it appears to most devices as UDP packets.
However, as there are already a number of tunnel protocols deployed However, as there are already a number of tunnel protocols deployed
in network virtualization environments, there is a practical question in network virtualization environments, there is a practical question
of transition and coexistence. of transition and coexistence.
Since Geneve is a superset of the functionality of the most common Since Geneve builds on the base data plane functionality provided by
protocols used for network virtualization (VXLAN,NVGRE) it should be the most common protocols used for network virtualization (VXLAN,
straightforward to port an existing control plane to run on top of it NVGRE) it should be straightforward to port an existing control plane
with minimal effort. With both the old and new packet formats to run on top of it with minimal effort. With both the old and new
supporting the same set of capabilities, there is no need for a hard packet formats supporting the same set of capabilities, there is no
transition - tunnel endpoints directly communicating with each other need for a hard transition - tunnel endpoints directly communicating
use any common protocol, which may be different even within a single with each other can use any common protocol, which may be different
overall system. As transit devices are primarily forwarding packets even within a single overall system. As transit devices are
on the basis of the IP header, all protocols appear similar and these primarily forwarding packets on the basis of the IP header, all
devices do not introduce additional interoperability concerns. protocols appear similar and these devices do not introduce
additional interoperability concerns.
To assist with this transition, it is strongly suggested that To assist with this transition, it is strongly suggested that
implementations support simultaneous operation of both Geneve and implementations support simultaneous operation of both Geneve and
existing tunnel protocols as it is expected to be common for a single existing tunnel protocols as it is expected to be common for a single
node to communicate with a mixture of other nodes. Eventually, older node to communicate with a mixture of other nodes. Eventually, older
protocols may be phased out as they are no longer in use. protocols may be phased out as they are no longer in use.
6. Security Considerations 6. Security Considerations
As encapsulated within a UDP/IP packet, Geneve does not have any As encapsulated within a UDP/IP packet, Geneve does not have any
inherent security mechanisms. As a result, an attacker with access inherent security mechanisms. As a result, an attacker with access
to the underlay network transporting the IP packets has the ability to the underlay network transporting the IP packets has the ability
to snoop or inject packets. Compromised tunnel endpoints may also to snoop, alter or inject packets. Compromised tunnel endpoints or
spoof identifiers in the tunnel header to gain access to networks transit devices may also spoof identifiers in the tunnel header to
owned by other tenants. gain access to networks owned by other tenants.
Within a particular security domain, such as a data center operated Within a particular security domain, such as a data center operated
by a single service provider, the most common and highest performing by a single service provider, the most common and highest performing
security mechanism is isolation of trusted components. Tunnel security mechanism is isolation of trusted components. Tunnel
traffic can be carried over a separate VLAN and filtered at any traffic can be carried over a separate VLAN and filtered at any
untrusted boundaries. In addition, tunnel endpoints should only be untrusted boundaries.
operated in environments controlled by the service provider, such as
the hypervisor itself rather than within a customer VM.
When crossing an untrusted link, such as the public Internet, IPsec When crossing an untrusted link, such as the general Internet, VPN
[RFC4301] may be used to provide authentication and/or encryption of technologies such as IPsec [RFC4301] should be used to provide
the IP packets formed as part of Geneve encapsulation. authentication and/or encryption of the IP packets formed as part of
Geneve encapsulation (See Section 6.1.1).
Geneve does not otherwise affect the security of the encapsulated Geneve does not otherwise affect the security of the encapsulated
packets. As per the guidelines of BCP 72 [RFC3552], the following packets. As per the guidelines of BCP 72 [RFC3552], the following
sections describe potential security risks that may be applicable to sections describe potential security risks that may be applicable to
Geneve deployments and approaches to mitigate such risks. It is also Geneve deployments and approaches to mitigate such risks. It is also
noted that not all such risks are applicable to all Geneve deployment noted that not all such risks are applicable to all Geneve deployment
scenarios, i.e., only a subset may be applicable to certain scenarios, i.e., only a subset may be applicable to certain
deployments. So an operator has to make an assessment based on their deployments. So an operator has to make an assessment based on their
network environment and determine the risks that are applicable to network environment and determine the risks that are applicable to
their specific environment and use appropriate mitigation approaches their specific environment and use appropriate mitigation approaches
skipping to change at page 26, line 34 skipping to change at page 27, line 28
Geneve is a network virtualization overlay encapsulation protocol Geneve is a network virtualization overlay encapsulation protocol
designed to establish tunnels between NVEs over an existing IP designed to establish tunnels between NVEs over an existing IP
network. It can be used to deploy multi-tenant overlay networks over network. It can be used to deploy multi-tenant overlay networks over
an existing IP underlay network in a public or private data center. an existing IP underlay network in a public or private data center.
The overlay service is typically provided by a service provider, for The overlay service is typically provided by a service provider, for
example a cloud services provider or a private data center operator, example a cloud services provider or a private data center operator,
this may or not may be the same provider as an underlay service this may or not may be the same provider as an underlay service
provider. Due to the nature of multi-tenancy in such environments, a provider. Due to the nature of multi-tenancy in such environments, a
tenant system may expect data confidentiality to ensure its packet tenant system may expect data confidentiality to ensure its packet
data is not tampered with (active attack) in transit or a target of data is not tampered with (active attack) in transit or a target of
unauthorized monitoring (passive attack). A tenant may expect the unauthorized monitoring (passive attack) for example by other tenant
overlay service provider to provide data confidentiality as part of systems or underlay service provider. A compromised network node or
the service or a tenant may bring its own data confidentiality a transit device within a data center may passively monitor Geneve
mechanisms like IPsec or TLS to protect the data end to end between packet data between NVEs; or route traffic for further inspection. A
its tenant systems. tenant may expect the overlay service provider to provide data
confidentiality as part of the service or a tenant may bring its own
data confidentiality mechanisms like IPsec or TLS to protect the data
end to end between its tenant systems. The overlay provider is
expected to provide cryptographic protection in cases where the
underlay provider is not the same as the overlay provider to ensure
the payload is not exposed to the underlay.
If an operator determines data confidentiality is necessary in their If an operator determines data confidentiality is necessary in their
environment based on their risk analysis, for example as in multi- environment based on their risk analysis, for example as in multi-
tenant environments, then an encryption mechanism SHOULD be used to tenant environments, then an encryption mechanism SHOULD be used to
encrypt the tenant data end to end between the NVEs. The NVEs may encrypt the tenant data end to end between the NVEs. The NVEs may
use existing well established encryption mechanisms such as IPsec, use existing well established encryption mechanisms such as IPsec,
DTLS, etc. DTLS, etc.
6.1.1. Inter-Data Center Traffic 6.1.1. Inter-Data Center Traffic
A tenant system in a customer premises (private data center) may want A tenant system in a customer premises (private data center) may want
to connect to tenant systems on their tenant overlay network in a to connect to tenant systems on their tenant overlay network in a
public cloud data center or a tenant may want to have its tenant public cloud data center or a tenant may want to have its tenant
systems located in multiple geographically separated data centers for systems located in multiple geographically separated data centers for
high availability. Geneve data traffic between tenant systems across high availability. Geneve data traffic between tenant systems across
such separated networks should be protected from threats when such separated networks should be protected from threats when
traversing public networks. Any Geneve overlay data leaving the data traversing public networks. Any Geneve overlay data leaving the data
center network beyond the operator's security domain SHOULD be center network beyond the operator's security domain SHOULD be
secured by encryption mechanisms such as IPsec or other VPN secured by encryption mechanisms such as IPsec or other VPN
mechanisms to protect the communications between the NVEs when they technologies to protect the communications between the NVEs when they
are geographically separated over untrusted network links. are geographically separated over untrusted network links.
Specification of data protection mechanisms employed between data Specification of data protection mechanisms employed between data
centers is beyond the scope of this document. centers is beyond the scope of this document.
The principles described in Section 4 regarding controlled
environments still apply to the geographically separated data center
usage outlined in this section.
6.2. Data Integrity 6.2. Data Integrity
Geneve encapsulation is used between NVEs to establish overlay Geneve encapsulation is used between NVEs to establish overlay
tunnels over an existing IP underlay network. In a multi-tenant data tunnels over an existing IP underlay network. In a multi-tenant data
center, a rogue or compromised tenant system may try to launch a center, a rogue or compromised tenant system may try to launch a
passive attack such as monitoring the traffic of other tenants, or an passive attack such as monitoring the traffic of other tenants, or an
active attack such as trying to inject unauthorized Geneve active attack such as trying to inject unauthorized Geneve
encapsulated traffic such as spoofing, replay, etc., into the encapsulated traffic such as spoofing, replay, etc., into the
network. To prevent such attacks, an NVE MUST NOT propagate Geneve network. To prevent such attacks, an NVE MUST NOT propagate Geneve
packets beyond the NVE to tenant systems and SHOULD employ packet packets beyond the NVE to tenant systems and SHOULD employ packet
filtering mechanisms so as not to forward unauthorized traffic filtering mechanisms so as not to forward unauthorized traffic
between TSs in different tenant networks. between tenant systems in different tenant networks. An NVE MUST NOT
interpret Geneve packets from tenant systems other than as frames to
be encapsulated.
A compromised network node or a transit device within a data center A compromised network node or a transit device within a data center
may launch an active attack trying to tamper with the Geneve packet may launch an active attack trying to tamper with the Geneve packet
data between NVEs. Malicious tampering of Geneve header fields may data between NVEs. Malicious tampering of Geneve header fields may
cause the packet from one tenant to be forwarded to a different cause the packet from one tenant to be forwarded to a different
tenant network. If an operator determines the possibility of such tenant network. If an operator determines the possibility of such
threat in their environment, the operator may choose to employ data threat in their environment, the operator may choose to employ data
integrity mechanisms between NVEs. In order to prevent such risks, a integrity mechanisms between NVEs. In order to prevent such risks, a
data integrity mechanism SHOULD be used in such environments to data integrity mechanism SHOULD be used in such environments to
protect the integrity of Geneve packets including packet headers, protect the integrity of Geneve packets including packet headers,
options and payload on communications between NVE pairs. A options and payload on communications between NVE pairs. A
cryptographic data protection mechanism such as IPsec may be used to cryptographic data protection mechanism such as IPsec may be used to
provide data integrity protection. A data center operator may choose provide data integrity protection. A data center operator may choose
to deploy any other data integrity mechanisms as applicable and to deploy any other data integrity mechanisms as applicable and
supported in their underlay networks. supported in their underlay networks, although non-cryptographic
mechanisms may not protect the Geneve portion of the packet from
tampering.
6.3. Authentication of NVE peers 6.3. Authentication of NVE peers
A rogue network device or a compromised NVE in a data center A rogue network device or a compromised NVE in a data center
environment might be able to spoof Geneve packets as if it came from environment might be able to spoof Geneve packets as if it came from
a legitimate NVE. In order to mitigate such a risk, an operator a legitimate NVE. In order to mitigate such a risk, an operator
SHOULD use an authentication mechanism, such as IPsec to ensure that SHOULD use an authentication mechanism, such as IPsec to ensure that
the Geneve packet originated from the intended NVE peer, in the Geneve packet originated from the intended NVE peer, in
environments where the operator determines spoofing or rogue devices environments where the operator determines spoofing or rogue devices
is a potential threat. Other simpler source checks such as ingress is a potential threat. Other simpler source checks such as ingress
skipping to change at page 28, line 19 skipping to change at page 29, line 29
Options, if present in the packet, are generated and terminated by Options, if present in the packet, are generated and terminated by
tunnel endpoints. As indicated in Section 2.2.1, transit devices may tunnel endpoints. As indicated in Section 2.2.1, transit devices may
interpret the options. However, if the packet is protected by tunnel interpret the options. However, if the packet is protected by tunnel
endpoint to tunnel endpoint encryption, for example through IPsec, endpoint to tunnel endpoint encryption, for example through IPsec,
transit devices will not have visibility into the Geneve header or transit devices will not have visibility into the Geneve header or
options in the packet. In such cases transit devices MUST handle options in the packet. In such cases transit devices MUST handle
Geneve packets as any other IP packet and maintain consistent Geneve packets as any other IP packet and maintain consistent
forwarding behavior. In cases where options are interpreted by forwarding behavior. In cases where options are interpreted by
transit devices, the operator MUST ensure that transit devices are transit devices, the operator MUST ensure that transit devices are
trusted and not compromised. Implementation of a mechanism to ensure trusted and not compromised. The definition of a mechanism to ensure
this trust is beyond the scope of this document. this trust is beyond the scope of this document.
6.5. Multicast/Broadcast 6.5. Multicast/Broadcast
In typical data center networks where IP multicasting is not In typical data center networks where IP multicasting is not
supported in the underlay network, multicasting may be supported supported in the underlay network, multicasting may be supported
using multiple unicast tunnels. The same security requirements as using multiple unicast tunnels. The same security requirements as
described in the above sections can be used to protect Geneve described in the above sections can be used to protect Geneve
communications between NVE peers. If IP multicasting is supported in communications between NVE peers. If IP multicasting is supported in
the underlay network and the operator chooses to use it for multicast the underlay network and the operator chooses to use it for multicast
traffic among tunnel endpoints, then the operator in such traffic among tunnel endpoints, then the operator in such
environments may use data protection mechanisms such as IPsec with environments may use data protection mechanisms such as IPsec with
Multicast extensions [RFC5374] to protect multicast traffic among multicast extensions [RFC5374] to protect multicast traffic among
Geneve NVE groups. Geneve NVE groups.
6.6. Control Plane Communications 6.6. Control Plane Communications
A Network Virtualization Authority (NVA) as outlined in [RFC8014] may A Network Virtualization Authority (NVA) as outlined in [RFC8014] may
be used as a control plane for configuring and managing the Geneve be used as a control plane for configuring and managing the Geneve
NVEs. The data center operator is expected to use security NVEs. The data center operator is expected to use security
mechanisms to protect the communications between the NVA to NVEs and mechanisms to protect the communications between the NVA to NVEs and
use authentication mechanisms to detect any rogue or compromised NVEs use authentication mechanisms to detect any rogue or compromised NVEs
within their administrative domain. Data protection mechanisms for within their administrative domain. Data protection mechanisms for
control plane communication or authentication mechanisms between the control plane communication or authentication mechanisms between the
NVA and the NVEs is beyond the scope of this document. NVA and the NVEs are beyond the scope of this document.
7. IANA Considerations 7. IANA Considerations
IANA has allocated UDP port 6081 as the well-known destination port IANA has allocated UDP port 6081 as the well-known destination port
for Geneve. Upon publication, the registry should be updated to cite for Geneve. An early registration for Geneve has been made at the
this document. The original request was: Service Name and Transport Protocol Port Number Registry [IANA-SN] as
noted below:
Service Name: geneve Service Name: geneve
Transport Protocol(s): UDP Transport Protocol(s): UDP
Assignee: Jesse Gross <jesse@kernel.org> Assignee: Jesse Gross <jesse@kernel.org>
Contact: Jesse Gross <jesse@kernel.org> Contact: Jesse Gross <jesse@kernel.org>
Description: Generic Network Virtualization Encapsulation (Geneve) Description: Generic Network Virtualization Encapsulation (Geneve)
Reference: This document Reference: This document
Port Number: 6081 Port Number: 6081
In addition, IANA is requested to create a "Geneve Option Class" Upon publication of this document, this registration will have its
registry to allocate Option Classes. This shall be a registry of reference changed to cite this document [RFC-to-be] and inline with
16-bit hexadecimal values along with descriptive strings. The [RFC6335] the Assignee and Contact of the port entry should be
identifiers 0x0-0xFF are to be reserved for standardized options for changed to IESG <iesg@ietf.org> and IETF Chair <chair@ietf.org>
allocation by IETF Review [RFC8126] and 0xFFF0-0xFFFF for respectively.
Experimental Use. Otherwise, identifiers are to be assigned to any
organization with an interest in creating Geneve options on a First
Come First Served basis. The registry is to be populated with the
following initial values:
+----------------+--------------------------------------+ In addition, IANA is requested to create a new "Geneve Option Class"
| Option Class | Description | registry to allocate Option Classes. This registry is to be placed
+----------------+--------------------------------------+ under a new Network Virtualization Overlay (NVO3) protocols page (to
| 0x0000..0x00FF | Unassigned - IETF Review | be created) in IANA protocol registries [IANA-PR]. The Geneve Option
| 0x0100 | Linux | Class registry shall consist of 16-bit hexadecimal values along with
| 0x0101 | Open vSwitch (OVS) | descriptive strings, Assignee/Contact information and References.
| 0x0102 | Open Virtual Networking (OVN) | The registration rules for the new registry are (as defined by
| 0x0103 | In-band Network Telemetry (INT) | [RFC8126]):
| 0x0104 | VMware, Inc. |
| 0x0105 | Amazon.com, Inc. | +----------------+-------------------------+
| 0x0106 | Cisco Systems, Inc. | | Range | Registration Procedures |
| 0x0107 | Oracle Corporation | +----------------+-------------------------+
| 0x0108..0x110 | Amazon.com, Inc. | | 0x0000..0x00FF | IETF Review |
| 0x0111..0xFFEF | Unassigned - First Come First Served | | 0x0100..0xFEFF | First Come First Served |
| 0xFFF0..FFFF | Experimental | | 0xFF00..0xFFFF | Experimental Use |
+----------------+--------------------------------------+ +----------------+-------------------------+
Inital registrations in the new registry are as follows:
+----------------+------------------+------------------+------------+
| Option Class | Description | Assignee/Contact | References |
+----------------+------------------+------------------+------------+
| 0x0100 | Linux | | |
| 0x0101 | Open vSwitch | | |
| | (OVS) | | |
| 0x0102 | Open Virtual | | |
| | Networking (OVN) | | |
| 0x0103 | In-band Network | | |
| | Telemetry (INT) | | |
| 0x0104 | VMware, Inc. | | |
| 0x0105 | Amazon.com, Inc. | | |
| 0x0106 | Cisco Systems, | | |
| | Inc. | | |
| 0x0107 | Oracle | | |
| | Corporation | | |
| 0x0108..0x0110 | Amazon.com, Inc. | | |
+----------------+------------------+------------------+------------+
8. Contributors 8. Contributors
The following individuals were authors of an earlier version of this The following individuals were authors of an earlier version of this
document and made significant contributions: document and made significant contributions:
Pankaj Garg Pankaj Garg
Microsoft Corporation Microsoft Corporation
1 Microsoft Way 1 Microsoft Way
Redmond, WA 98052 Redmond, WA 98052
skipping to change at page 30, line 49 skipping to change at page 32, line 49
Ariel Hendel Ariel Hendel
Facebook, Inc. Facebook, Inc.
1 Hacker Way 1 Hacker Way
Menlo Park, CA 94025 Menlo Park, CA 94025
USA USA
Email: ahendel@fb.com Email: ahendel@fb.com
9. Acknowledgements 9. Acknowledgements
The authors wish to thank Martin Casado, Bruce Davie and Dave Thaler The authors wish to acknowledge Puneet Agarwal, David Black, Sami
for their input, feedback, and helpful suggestions. Boutros, Scott Bradner, Martin Casado, Alissa Cooper, Roman Danyliw,
Bruce Davie, Anoop Ghanwani, Benjamin Kaduk, Suresh Krishnan, Mirja
The authors would like to thank Magnus Nystrom for his reviews and Kuhlewind, Barry Leiba, Daniel Migault, Greg Mirksy, Tal Mizrahi,
feedback. Kathleen Moriarty, Magnus Nystrom, Adam Roach, Sabrina Tanamal, Dave
Thaler, Eric Vyncke, Magnus Westerlund and many other members of the
Thanks to Daniel Migault, Anoop Ghanwani, Greg Mirksy, Puneet NVO3 WG for their reviews, comments and suggestions.
Agarwal, and Tal Mizrahi for their reviews, comments and feedback.
The authors would like to thank David Black for his detailed reviews
and valuable inputs.
Thanks to Sami Boutros for his inputs and helpful feedback.
The authors would like to thank Matthew Bocci, Sam Aldrin, Benson The authors would like to thank Sam Aldrin, Alia Atlas, Matthew
Schliesser, Martin Vigoureux, and Alia Atlas for their guidance Bocci, Benson Schliesser, and Martin Vigoureux for their guidance
throughout the process. throughout the process.
10. References 10. References
10.1. Normative References 10.1. Normative References
[RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768, [RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
DOI 10.17487/RFC0768, August 1980, DOI 10.17487/RFC0768, August 1980,
<https://www.rfc-editor.org/info/rfc768>. <https://www.rfc-editor.org/info/rfc768>.
[RFC0792] Postel, J., "Internet Control Message Protocol", STD 5, [RFC0792] Postel, J., "Internet Control Message Protocol", STD 5,
RFC 792, DOI 10.17487/RFC0792, September 1981, RFC 792, DOI 10.17487/RFC0792, September 1981,
<https://www.rfc-editor.org/info/rfc792>. <https://www.rfc-editor.org/info/rfc792>.
[RFC1112] Deering, S., "Host extensions for IP multicasting", STD 5, [RFC1112] Deering, S., "Host extensions for IP multicasting", STD 5,
RFC 1112, DOI 10.17487/RFC1112, August 1989, RFC 1112, DOI 10.17487/RFC1112, August 1989,
<https://www.rfc-editor.org/info/rfc1112>. <https://www.rfc-editor.org/info/rfc1112>.
[RFC1191] Mogul, J. and S. Deering, "Path MTU discovery", RFC 1191,
DOI 10.17487/RFC1191, November 1990,
<https://www.rfc-editor.org/info/rfc1191>.
[RFC2003] Perkins, C., "IP Encapsulation within IP", RFC 2003,
DOI 10.17487/RFC2003, October 1996,
<https://www.rfc-editor.org/info/rfc2003>.
[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,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet [RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet
Control Message Protocol (ICMPv6) for the Internet Control Message Protocol (ICMPv6) for the Internet
Protocol Version 6 (IPv6) Specification", STD 89, Protocol Version 6 (IPv6) Specification", STD 89,
RFC 4443, DOI 10.17487/RFC4443, March 2006, RFC 4443, DOI 10.17487/RFC4443, March 2006,
<https://www.rfc-editor.org/info/rfc4443>. <https://www.rfc-editor.org/info/rfc4443>.
[RFC6935] Eubanks, M., Chimento, P., and M. Westerlund, "IPv6 and [RFC6040] Briscoe, B., "Tunnelling of Explicit Congestion
UDP Checksums for Tunneled Packets", RFC 6935, Notification", RFC 6040, DOI 10.17487/RFC6040, November
DOI 10.17487/RFC6935, April 2013, 2010, <https://www.rfc-editor.org/info/rfc6040>.
<https://www.rfc-editor.org/info/rfc6935>.
[RFC6936] Fairhurst, G. and M. Westerlund, "Applicability Statement [RFC6936] Fairhurst, G. and M. Westerlund, "Applicability Statement
for the Use of IPv6 UDP Datagrams with Zero Checksums", for the Use of IPv6 UDP Datagrams with Zero Checksums",
RFC 6936, DOI 10.17487/RFC6936, April 2013, RFC 6936, DOI 10.17487/RFC6936, April 2013,
<https://www.rfc-editor.org/info/rfc6936>. <https://www.rfc-editor.org/info/rfc6936>.
[RFC7365] Lasserre, M., Balus, F., Morin, T., Bitar, N., and Y.
Rekhter, "Framework for Data Center (DC) Network
Virtualization", RFC 7365, DOI 10.17487/RFC7365, October
2014, <https://www.rfc-editor.org/info/rfc7365>.
[RFC8085] Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage [RFC8085] Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage
Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085, Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085,
March 2017, <https://www.rfc-editor.org/info/rfc8085>. March 2017, <https://www.rfc-editor.org/info/rfc8085>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26, Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017, RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>. <https://www.rfc-editor.org/info/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/info/rfc8200>.
[RFC8201] McCann, J., Deering, S., Mogul, J., and R. Hinden, Ed.,
"Path MTU Discovery for IP version 6", STD 87, RFC 8201,
DOI 10.17487/RFC8201, July 2017,
<https://www.rfc-editor.org/info/rfc8201>.
10.2. Informative References 10.2. Informative References
[ETYPES] The IEEE Registration Authority, "IEEE 802 Numbers", 2013, [ETYPES] The IEEE Registration Authority, "IEEE 802 Numbers",
<http://www.iana.org/assignments/ieee-802-numbers/ieee- <https://www.iana.org/assignments/ieee-802-numbers>.
802-numbers.xml>.
[I-D.ietf-intarea-tunnels] [I-D.ietf-intarea-tunnels]
Touch, J. and M. Townsley, "IP Tunnels in the Internet Touch, J. and M. Townsley, "IP Tunnels in the Internet
Architecture", draft-ietf-intarea-tunnels-09 (work in Architecture", draft-ietf-intarea-tunnels-10 (work in
progress), July 2018. progress), September 2019.
[I-D.ietf-nvo3-dataplane-requirements] [I-D.ietf-nvo3-dataplane-requirements]
Bitar, N., Lasserre, M., Balus, F., Morin, T., Jin, L., Bitar, N., Lasserre, M., Balus, F., Morin, T., Jin, L.,
and B. Khasnabish, "NVO3 Data Plane Requirements", draft- and B. Khasnabish, "NVO3 Data Plane Requirements", draft-
ietf-nvo3-dataplane-requirements-03 (work in progress), ietf-nvo3-dataplane-requirements-03 (work in progress),
April 2014. April 2014.
[I-D.ietf-nvo3-encap] [I-D.ietf-nvo3-encap]
Boutros, S., "NVO3 Encapsulation Considerations", draft- Boutros, S., "NVO3 Encapsulation Considerations", draft-
ietf-nvo3-encap-02 (work in progress), September 2018. ietf-nvo3-encap-05 (work in progress), February 2020.
[IEEE.802.1Q_2014]
IEEE, "IEEE Standard for Local and metropolitan area
networks--Bridges and Bridged Networks", IEEE 802.1Q-2014,
DOI 10.1109/ieeestd.2014.6991462, December 2014,
<http://ieeexplore.ieee.org/servlet/
opac?punumber=6991460>.
[RFC1191] Mogul, J. and S. Deering, "Path MTU discovery", RFC 1191, [IANA-PR] IANA, "Protocol Registries",
DOI 10.17487/RFC1191, November 1990, <https://www.iana.org/protocols>.
<https://www.rfc-editor.org/info/rfc1191>.
[RFC2003] Perkins, C., "IP Encapsulation within IP", RFC 2003, [IANA-SN] IANA, "Service Name and Transport Protocol Port Number
DOI 10.17487/RFC2003, October 1996, Registry", <https://www.iana.org/assignments/service-
<https://www.rfc-editor.org/info/rfc2003>. names-port-numbers>.
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 [IEEE.802.1Q_2018]
(IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460, IEEE, "IEEE Standard for Local and Metropolitan Area
December 1998, <https://www.rfc-editor.org/info/rfc2460>. Networks--Bridges and Bridged Networks", IEEE 802.1Q-2018,
DOI 10.1109/ieeestd.2018.8403927, July 2018,
<http://ieeexplore.ieee.org/servlet/
opac?punumber=8403925>.
[RFC2983] Black, D., "Differentiated Services and Tunnels", [RFC2983] Black, D., "Differentiated Services and Tunnels",
RFC 2983, DOI 10.17487/RFC2983, October 2000, RFC 2983, DOI 10.17487/RFC2983, October 2000,
<https://www.rfc-editor.org/info/rfc2983>. <https://www.rfc-editor.org/info/rfc2983>.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol [RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031, Label Switching Architecture", RFC 3031,
DOI 10.17487/RFC3031, January 2001, DOI 10.17487/RFC3031, January 2001,
<https://www.rfc-editor.org/info/rfc3031>. <https://www.rfc-editor.org/info/rfc3031>.
skipping to change at page 33, line 45 skipping to change at page 36, line 5
[RFC4301] Kent, S. and K. Seo, "Security Architecture for the [RFC4301] Kent, S. and K. Seo, "Security Architecture for the
Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
December 2005, <https://www.rfc-editor.org/info/rfc4301>. December 2005, <https://www.rfc-editor.org/info/rfc4301>.
[RFC5374] Weis, B., Gross, G., and D. Ignjatic, "Multicast [RFC5374] Weis, B., Gross, G., and D. Ignjatic, "Multicast
Extensions to the Security Architecture for the Internet Extensions to the Security Architecture for the Internet
Protocol", RFC 5374, DOI 10.17487/RFC5374, November 2008, Protocol", RFC 5374, DOI 10.17487/RFC5374, November 2008,
<https://www.rfc-editor.org/info/rfc5374>. <https://www.rfc-editor.org/info/rfc5374>.
[RFC6040] Briscoe, B., "Tunnelling of Explicit Congestion [RFC6335] Cotton, M., Eggert, L., Touch, J., Westerlund, M., and S.
Notification", RFC 6040, DOI 10.17487/RFC6040, November Cheshire, "Internet Assigned Numbers Authority (IANA)
2010, <https://www.rfc-editor.org/info/rfc6040>. Procedures for the Management of the Service Name and
Transport Protocol Port Number Registry", BCP 165,
RFC 6335, DOI 10.17487/RFC6335, August 2011,
<https://www.rfc-editor.org/info/rfc6335>.
[RFC6438] Carpenter, B. and S. Amante, "Using the IPv6 Flow Label
for Equal Cost Multipath Routing and Link Aggregation in
Tunnels", RFC 6438, DOI 10.17487/RFC6438, November 2011,
<https://www.rfc-editor.org/info/rfc6438>.
[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,
<https://www.rfc-editor.org/info/rfc7348>. <https://www.rfc-editor.org/info/rfc7348>.
[RFC7365] Lasserre, M., Balus, F., Morin, T., Bitar, N., and Y.
Rekhter, "Framework for Data Center (DC) Network
Virtualization", RFC 7365, DOI 10.17487/RFC7365, October
2014, <https://www.rfc-editor.org/info/rfc7365>.
[RFC7637] Garg, P., Ed. and Y. Wang, Ed., "NVGRE: Network [RFC7637] Garg, P., Ed. and Y. Wang, Ed., "NVGRE: Network
Virtualization Using Generic Routing Encapsulation", Virtualization Using Generic Routing Encapsulation",
RFC 7637, DOI 10.17487/RFC7637, September 2015, RFC 7637, DOI 10.17487/RFC7637, September 2015,
<https://www.rfc-editor.org/info/rfc7637>. <https://www.rfc-editor.org/info/rfc7637>.
[RFC8014] Black, D., Hudson, J., Kreeger, L., Lasserre, M., and T. [RFC8014] Black, D., Hudson, J., Kreeger, L., Lasserre, M., and T.
Narten, "An Architecture for Data-Center Network Narten, "An Architecture for Data-Center Network
Virtualization over Layer 3 (NVO3)", RFC 8014, Virtualization over Layer 3 (NVO3)", RFC 8014,
DOI 10.17487/RFC8014, December 2016, DOI 10.17487/RFC8014, December 2016,
<https://www.rfc-editor.org/info/rfc8014>. <https://www.rfc-editor.org/info/rfc8014>.
[RFC8086] Yong, L., Ed., Crabbe, E., Xu, X., and T. Herbert, "GRE- [RFC8086] Yong, L., Ed., Crabbe, E., Xu, X., and T. Herbert, "GRE-
in-UDP Encapsulation", RFC 8086, DOI 10.17487/RFC8086, in-UDP Encapsulation", RFC 8086, DOI 10.17487/RFC8086,
March 2017, <https://www.rfc-editor.org/info/rfc8086>. March 2017, <https://www.rfc-editor.org/info/rfc8086>.
[RFC8201] McCann, J., Deering, S., Mogul, J., and R. Hinden, Ed.,
"Path MTU Discovery for IP version 6", STD 87, RFC 8201,
DOI 10.17487/RFC8201, July 2017,
<https://www.rfc-editor.org/info/rfc8201>.
[RFC8293] Ghanwani, A., Dunbar, L., McBride, M., Bannai, V., and R. [RFC8293] Ghanwani, A., Dunbar, L., McBride, M., Bannai, V., and R.
Krishnan, "A Framework for Multicast in Network Krishnan, "A Framework for Multicast in Network
Virtualization over Layer 3", RFC 8293, Virtualization over Layer 3", RFC 8293,
DOI 10.17487/RFC8293, January 2018, DOI 10.17487/RFC8293, January 2018,
<https://www.rfc-editor.org/info/rfc8293>. <https://www.rfc-editor.org/info/rfc8293>.
[VL2] "VL2: A Scalable and Flexible Data Center Network", ACM [VL2] "VL2: A Scalable and Flexible Data Center Network", ACM
SIGCOMM Computer Communication Review, SIGCOMM Computer Communication Review,
DOI 10.1145/1594977.1592576, 2009, DOI 10.1145/1594977.1592576, 2009,
<http://www.sigcomm.org/sites/default/files/ccr/ <http://www.sigcomm.org/sites/default/files/ccr/
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