Generic Protocol Extension for VXLAN
draft-ietf-nvo3-vxlan-gpe-01
The information below is for an old version of the document.
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|---|---|---|---|
| Authors | Paul Quinn , Rajeev Manur , Larry Kreeger , Darrel Lewis , Fabio Maino , Michael Smith , Puneet Agarwal , Lucy Yong , Xiaohu Xu , Uri Elzur , Pankaj Garg , David T. Melman | ||
| Last updated | 2015-11-04 | ||
| Replaces | draft-quinn-vxlan-gpe | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
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draft-ietf-nvo3-vxlan-gpe-01
Network Working Group P. Quinn
Internet-Draft Cisco Systems, Inc.
Intended status: Standards Track R. Manur
Expires: May 7, 2016 Broadcom
L. Kreeger
D. Lewis
F. Maino
M. Smith
Cisco Systems, Inc.
P. Agarwal
Innovium, Inc
L. Yong
Huawei USA
X. Xu
Huawei Technologies
U. Elzur
Intel
P. Garg
Microsoft
D. Melman
Marvell
November 4, 2015
Generic Protocol Extension for VXLAN
draft-ietf-nvo3-vxlan-gpe-01.txt
Abstract
This draft describes extending Virtual eXtensible Local Area Network
(VXLAN), via changes to the VXLAN header, with three new
capabilities: support for multi-protocol encapsulation, operations,
administration and management (OAM) signaling and explicit
versioning.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on May 7, 2016.
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. VXLAN Without Protocol Extension . . . . . . . . . . . . . . . 5
3. Generic Protocol Extension for VXLAN (VXLAN GPE) . . . . . . . 7
3.1. VXLAN GPE Header . . . . . . . . . . . . . . . . . . . . . 7
3.2. Multi Protocol Support . . . . . . . . . . . . . . . . . . 8
3.3. OAM Support . . . . . . . . . . . . . . . . . . . . . . . 8
3.4. Version Bits . . . . . . . . . . . . . . . . . . . . . . . 8
4. Outer Encapsulations . . . . . . . . . . . . . . . . . . . . . 9
4.1. Inner VLAN Tag Handling . . . . . . . . . . . . . . . . . 13
4.2. Fragmentation Considerations . . . . . . . . . . . . . . . 13
5. Backward Compatibility . . . . . . . . . . . . . . . . . . . . 14
5.1. VXLAN VTEP to VXLAN GPE VTEP . . . . . . . . . . . . . . . 14
5.2. VXLAN GPE VTEP to VXLAN VTEP . . . . . . . . . . . . . . . 14
5.3. VXLAN GPE UDP Ports . . . . . . . . . . . . . . . . . . . 14
5.4. VXLAN GPE and Encapsulated IP Header Fields . . . . . . . 14
6. VXLAN GPE Examples . . . . . . . . . . . . . . . . . . . . . . 15
7. Security Considerations . . . . . . . . . . . . . . . . . . . 17
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19
9.1. UDP Port . . . . . . . . . . . . . . . . . . . . . . . . . 19
9.2. VXLAN GPE Next Protocol . . . . . . . . . . . . . . . . . 19
9.3. VXLAN GPE Flag and Reserved Bits . . . . . . . . . . . . . 19
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 21
10.1. Normative References . . . . . . . . . . . . . . . . . . . 21
10.2. Informative References . . . . . . . . . . . . . . . . . . 21
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 23
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1. Introduction
Virtual eXtensible Local Area Network VXLAN [RFC7348] defines an
encapsulation format that encapsulates Ethernet frames in an outer
UDP/IP transport. As data centers evolve, the need to carry other
protocols encapsulated in an IP packet is required, as well as the
need to provide increased visibility and diagnostic capabilities
within the overlay. The VXLAN header does not specify the protocol
being encapsulated and therefore is currently limited to
encapsulating only Ethernet frame payload, nor does it provide the
ability to define OAM protocols. In addition, [RFC6335] requires
that new transports not use transport layer port numbers to identify
tunnel payload, rather it encourages encapsulations to use their own
identifiers for this purpose. VXLAN GPE is intended to extend the
existing VXLAN protocol to provide protocol typing, OAM, and
versioning capabilities.
The Version and OAM bits are introduced in Section 3, and the choice
of location for these fields is driven by minimizing the impact on
existing deployed hardware.
In order to facilitate deployments of VXLAN GPE with hardware
currently deployed to support VXLAN, changes from legacy VXLAN have
been kept to a minimum. Section 5 provides a detailed discussion
about how VXLAN GPE addresses the requirement for backward
compatibility with VXLAN.
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2. VXLAN Without Protocol Extension
VXLAN provides a method of creating multi-tenant overlay networks by
encapsulating packets in IP/UDP along with a header containing a
network identifier which is used to isolate tenant traffic in each
overlay network from each other. This allows the overlay networks to
run over an existing IP network.
Through this encapsulation, VXLAN creates stateless tunnels between
VXLAN Tunnel End Points (VTEPs) which are responsible for adding/
removing the IP/UDP/VXLAN headers and providing tenant traffic
isolation based on the VXLAN Network Identifier (VNI). Tenant
systems are unaware that their networking service is being provided
by an overlay.
When encapsulating packets, a VTEP must know the IP address of the
proper remote VTEP at the far end of the tunnel that can deliver the
inner packet to the Tenant System corresponding to the inner
destination address. In the case of tenant multicast or broadcast,
the outer IP address may be an IP multicast group address, or the
VTEP may replicate the packet and send it to all known VTEPs. If
multicast is used in the underlay network to send encapsulated
packets to remote VTEPs, Any Source Multicast is used and each VTEP
serving a particular VNI must perform a (*, G) join to the same group
IP address.
Inner to outer address mapping can be determined in two ways. One is
source based learning in the data plane, and the other is
distribution via a control plane.
Source based learning requires a receiving VTEP to create an inner to
outer address mapping by gleaning the information from the received
packets by correlating the inner source address to the outer source
IP address. When a mapping does not exist, a VTEP forwards the
packets to all remote VTEPs participating in the VNI by using IP
multicast in the IP underlay network. Each VTEP must be configured
with the IP multicast address to use for each VNI. How this occurs
is out of scope.
The control plane used to distribute inner to outer mappings is also
out of scope. It could use a centralized authority or be
distributed, or use a hybrid.
The VXLAN Network Identifier (VNI) provides scoping for the addresses
in the header of the encapsulated PDU. If the encapsulated packet is
an Ethernet frame, this means the Ethernet MAC addresses are only
unique within a given VNI and may overlap with MAC addresses within a
different VNI. If the encapsulated packet is an IP packet, this
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means the IP addresses are only unique within that VNI.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R|R|R|R|I|R|R|R| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VXLAN Network Identifier (VNI) | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: VXLAN Header
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3. Generic Protocol Extension for VXLAN (VXLAN GPE)
3.1. VXLAN GPE Header
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R|R|Ver|I|P|R|O| Reserved |Next Protocol |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VXLAN Network Identifier (VNI) | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: VXLAN GPE Header
Flags (8 bits): The first 8 bits of the header are the flag field.
The bits designated "R" above are reserved flags. These MUST be
set to zero on transmission and ignored on receipt.
Version (Ver): Indicates VXLAN GPE protocol version. The initial
version is 0. If a receiver does not support the version
indicated it MUST drop the packet.
Instance Bit (I bit): The I bit MUST be set to indicate a valid VNI.
Next Protocol Bit (P bit): The P bit is set to indicate that the
Next Protocol field is present.
OAM Flag Bit (O bit): The O bit is set to indicate that the packet
is an OAM packet.
Next Protocol: This 8 bit field indicates the protocol header
immediately following the VXLAN GPE header.
VNI: This 24 bit field identifies the VXLAN overlay network the
inner packet belongs to. Inner packets belonging to different
VNIs cannot communicate with each other (unless explicitly allowed
by policy).
Reserved: Reserved fields MUST be set to zero on transmission and
ignored on receipt.
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3.2. Multi Protocol Support
This draft defines the following two changes to the VXLAN header in
order to support multi-protocol encapsulation:
P Bit: Flag bit 5 is defined as the Next Protocol bit. The P bit
MUST be set to 1 to indicate the presence of the 8 bit next
protocol field. When P=1, the destination UDP port MUST be 4790.
P = 0 indicates that the payload MUST conform to VXLAN as defined
in [RFC7348], including destination UDP port.
Flag bit 5 was chosen as the P bit because this flag bit is
currently reserved in VXLAN.
Next Protocol Field: The lower 8 bits of the first word are used to
carry a next protocol. This next protocol field contains the
protocol of the encapsulated payload packet. A new protocol
registry will be requested from IANA, see section 9.2.
This draft defines the following Next Protocol values:
0x1 : IPv4
0x2 : IPv6
0x3 : Ethernet
0x4 : Network Service Header [NSH]
0x5 : Multiprotocol Label Switching [RFC3031]. Please see
[idrtun] for more details.
3.3. OAM Support
Flag bit 7 is defined as the O bit. When the O bit is set to 1, the
packet is an OAM packet and OAM processing MUST occur. Other header
fields including Next Protocol MUST adhere to the definitions in
section 3. The OAM protocol details are out of scope for this
document. As with the P-bit, bit 7 is currently a reserved flag in
VXLAN.
3.4. Version Bits
VXLAN GPE bits 2 and 3 are defined as version bits. These bits are
reserved in VXLAN. The version field is used to ensure backward
compatibility going forward with future VXLAN GPE updates.
The initial version for VXLAN GPE is 0.
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4. Outer Encapsulations
In addition to the VXLAN GPE header, the packet is further
encapsulated in UDP and IP. Data centers based on Ethernet, will
then send this IP packet over Ethernet.
Outer UDP Header:
Destination UDP Port: IANA has assigned the value 4790 for the VXLAN
GPE UDP port. This well-known destination port is used when sending
VXLAN GPE encapsulated packets.
Source UDP Port: The source UDP port is used as entropy for devices
forwarding encapsulated packets across the underlay (ECMP for IP
routers, or load splitting for link aggregation by bridges). Tenant
traffic flows should all use the same source UDP port to lower the
chances of packet reordering by the underlay for a given flow. It is
recommended for VTEPs to generate this port number using a hash of
the inner packet headers. Implementations MAY use the entire 16 bit
source UDP port for entropy.
UDP Checksum: Source VTEPs MAY either calculate a valid checksum, or
if this is not possible, set the checksum to zero. When calculating
a checksum, it MUST be calculated across the entire packet (outer IP
header, UDP header, VXLAN GPE header and payload packet). All
receiving VTEPs must accept a checksum value of zero. If the
receiving VTEP is capable of validating the checksum, it MAY validate
a non-zero checksum and MUST discard the packet if the checksum is
determined to be invalid.
Outer IP Header:
This is the header used by the underlay network to deliver packets
between VTEPs. The destination IP address can be a unicast or a
multicast IP address. The source IP address must be the source VTEP
IP address which can be used to return tenant packets to the tenant
system source address within the inner packet header.
When the outer IP header is IPv4, VTEPs MUST set the DF bit.
Outer Ethernet Header:
Most data centers networks are built on Ethernet. Assuming the outer
IP packet is being sent across Ethernet, there will be an Ethernet
header used to deliver the IP packet to the next hop, which could be
the destination VTEP or be a router used to forward the IP packet
towards the destination VTEP. If VLANs are in use within the data
center, then this Ethernet header would also contain a VLAN tag.
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The following figures show the entire stack of protocol headers that
would be seen on an Ethernet link carrying encapsulated packets from
a VTEP across the underlay network for both IPv4 and IPv6 based
underlay networks.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
Outer Ethernet Header:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Outer Destination MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Outer Destination MAC Address | Outer Source MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Outer Source MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opt Ethertype = C-Tag 802.1Q | Outer VLAN Tag |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ethertype = 0x0800 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Outer IPv4 Header:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Version| IHL |Type of Service| Total Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Identification |Flags| Fragment Offset |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Time to Live |Protocl=17(UDP)| Header Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Outer Source IPv4 Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Outer Destination IPv4 Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Outer UDP Header:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Port | Dest Port = 4790 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| UDP Length | UDP Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
VXLAN GPE Header:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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|R|R|Ver|I|P|R|O| Reserved |Next Protocol |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VXLAN Network Identifier (VNI) | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Payload:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Depends on VXLAN GPE Next Protocol field above. |
| Note that if the payload is Ethernet, then the original |
| Ethernet Frame's FCS is not included. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Frame Check Sequence:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| New FCS (Frame Check Sequence) for Outer Ethernet Frame |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Outer Headers for VXLAN GPE over IPv4
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
Outer Ethernet Header:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Outer Destination MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Outer Destination MAC Address | Outer Source MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Outer Source MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opt Ethertype = C-Tag 802.1Q | Outer VLAN Tag |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ethertype = 0x86DD |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Outer IPv6 Header:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Version| Traffic Class | Flow Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Payload Length | NxtHdr=17(UDP)| Hop Limit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
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| |
+ Outer Source IPv6 Address +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Outer Destination IPv6 Address +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Outer UDP Header:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Port | Dest Port = 4790 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| UDP Length | UDP Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
VXLAN GPE Header:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R|R|Ver|I|P|R|O| Reserved |Next Protocol |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VXLAN Network Identifier (VNI) | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Payload:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Depends on VXLAN GPE Next Protocol field above. |
| Note that if the payload is Ethernet, then the original |
| Ethernet Frame's FCS is not included. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Frame Check Sequence:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| New FCS (Frame Check Sequence) for Outer Ethernet Frame |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure X: Outer Headers for VXLAN GPE over IPv6
Figure 4: Outer Headers for VXLAN GPE over IPv6
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4.1. Inner VLAN Tag Handling
If the inner packet (as indicated by the VXLAN GPE Next Protocol
field) is an Ethernet frame, it is recommended that it does not
contain a VLAN tag. In the most common scenarios, the tenant VLAN
tag is translated into a VXLAN Network Identifier. In these
scenarios, VTEPs should never send an inner Ethernet frame with a
VLAN tag, and a VTEP performing decapsulation should discard any
inner frames received with a VLAN tag. However, if the VTEPs are
specifically configured to support it for a specific VXLAN Network
Identifier, a VTEP may support transparent transport of the inner
VLAN tag between all tenant systems on that VNI. The VTEP never
looks at the value of the inner VLAN tag, but simply passes it across
the underlay.
4.2. Fragmentation Considerations
VTEPs MUST never fragment an encapsulated VXLAN GPE packet, and when
the outer IP header is IPv4, VTEPs MUST set the DF bit in the outer
IPv4 header. It is recommended that the underlay network be
configured to carry an MTU at least large enough to accommodate the
added encapsulation headers. It is recommended that VTEPs perform
Path MTU discovery [RFC1191] [RFC1981] to determine if the underlay
network can carry the encapsulated payload packet.
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5. Backward Compatibility
5.1. VXLAN VTEP to VXLAN GPE VTEP
A VXLAN VTEP conforms to VXLAN frame format and uses UDP destination
port 4789 when sending traffic to VXLAN GPE VTEP. As per VXLAN,
reserved bits 5 and 7, VXLAN GPE P and O-bits respectively must be
set to zero. The remaining reserved bits must be zero, including the
VXLAN GPE version field, bits 2 and 3. The encapsulated payload MUST
be Ethernet.
5.2. VXLAN GPE VTEP to VXLAN VTEP
A VXLAN GPE VTEP MUST NOT encapsulate non-Ethernet frames to a VXLAN
VTEP. When encapsulating Ethernet frames to a VXLAN VTEP, the VXLAN
GPE VTEP MUST conform to VXLAN frame format and hence will set the P
bit to 0, the Next Protocol to 0 and use UDP destination port 4789.
A VXLAN GPE VTEP MUST also set O = 0 and Ver = 0 when encapsulating
Ethernet frames to VXLAN VTEP. The receiving VXLAN VTEP will treat
this packet as a VXLAN packet.
A method for determining the capabilities of a VXLAN VTEP (GPE or
non-GPE) is out of the scope of this draft.
5.3. VXLAN GPE UDP Ports
VXLAN GPE uses a IANA assigned UDP destination port, 4790, when
sending traffic to VXLAN GPE VTEPs.
5.4. VXLAN GPE and Encapsulated IP Header Fields
When encapsulating and decapsulating IPv4 and IPv6 packets, certain
fields, such as IPv4 Time to Live (TTL) from the inner IP header need
to be considered. VXLAN GPE IP encapsulation and decapsulation
utilizes the techniques described in [RFC6830], section 5.3.
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6. VXLAN GPE Examples
This section provides three examples of protocols encapsulated using
the Generic Protocol Extension for VXLAN described in this document.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R|R|0|0|I|1|R|0| Reserved | NP = IPv4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VXLAN Network Identifier (VNI) | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Original IPv4 Packet |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: IPv4 and VXLAN GPE
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R|R|0|0|I|1|R|0| Reserved | NP = IPv6 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VXLAN Network Identifier (VNI) | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Original IPv6 Packet |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: IPv6 and VXLAN GPE
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R|R|0|0|I|1|R|0| Reserved |NP = Ethernet |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VXLAN Network Identifier (VNI) | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Original Ethernet Frame |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: Ethernet and VXLAN GPE
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7. Security Considerations
VXLAN's security is focused on issues around L2 encapsulation into
L3. With VXLAN GPE, issues such as spoofing, flooding, and traffic
redirection are dependent on the particular protocol payload
encapsulated.
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8. Acknowledgments
A special thank you goes to Dino Farinacci for his guidance and
detailed review.
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9. IANA Considerations
9.1. UDP Port
UDP 4790 port has been assigned by IANA for VXLAN GPE.
9.2. VXLAN GPE Next Protocol
IANA is requested to set up a registry of "Next Protocol". These are
8-bit values. Next Protocol values 0, 1, 2, 3 and 4 are defined in
this draft. New values are assigned via Standards Action [RFC5226].
+---------------+-------------+---------------+
| Next Protocol | Description | Reference |
+---------------+-------------+---------------+
| 0 | Reserved | This document |
| | | |
| 1 | IPv4 | This document |
| | | |
| 2 | IPv6 | This document |
| | | |
| 3 | Ethernet | This document |
| | | |
| 4 | NSH | This document |
| | | |
| 5 | MPLS | This document |
| | | |
| 6..253 | Unassigned | |
+---------------+-------------+---------------+
Table 1
9.3. VXLAN GPE Flag and Reserved Bits
There are ten flag bits at the beginning of the VXLAN GPE header,
followed by 16 reserved bits and an 8-bit reserved field at the end
of the header. New bits are assigned via Standards Action [RFC5226].
Bits 0-1 - Reserved
Bits 2-3 - Version
Bit 4 - Instance ID (I bit)
Bit 5 - Next Protocol (P bit)
Bit 6 - Reserved
Bit 7 - OAM (O bit)
Bits 8-23 - Reserved
Bits 24-31 in the 2nd Word -- Reserved
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Reserved bits/fields MUST be set to 0 by the sender and ignored by
the receiver.
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10. References
10.1. Normative References
[RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
DOI 10.17487/RFC0768, August 1980,
<http://www.rfc-editor.org/info/rfc768>.
[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791,
DOI 10.17487/RFC0791, September 1981,
<http://www.rfc-editor.org/info/rfc791>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<http://www.rfc-editor.org/info/rfc5226>.
10.2. Informative References
[NSH] Quinn, P., Ed. and U. Elzur, Ed., "Network Service
Header", 2015.
[RFC1191] Mogul, J. and S. Deering, "Path MTU discovery", RFC 1191,
DOI 10.17487/RFC1191, November 1990,
<http://www.rfc-editor.org/info/rfc1191>.
[RFC1981] McCann, J., Deering, S., and J. Mogul, "Path MTU Discovery
for IP version 6", RFC 1981, DOI 10.17487/RFC1981,
August 1996, <http://www.rfc-editor.org/info/rfc1981>.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031, DOI 10.17487/
RFC3031, January 2001,
<http://www.rfc-editor.org/info/rfc3031>.
[RFC6335] Cotton, M., Eggert, L., Touch, J., Westerlund, M., and S.
Cheshire, "Internet Assigned Numbers Authority (IANA)
Procedures for the Management of the Service Name and
Transport Protocol Port Number Registry", BCP 165,
RFC 6335, DOI 10.17487/RFC6335, August 2011,
<http://www.rfc-editor.org/info/rfc6335>.
[RFC6830] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "The
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Locator/ID Separation Protocol (LISP)", RFC 6830,
DOI 10.17487/RFC6830, January 2013,
<http://www.rfc-editor.org/info/rfc6830>.
[RFC7348] Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger,
L., Sridhar, T., Bursell, M., and C. Wright, "Virtual
eXtensible Local Area Network (VXLAN): A Framework for
Overlaying Virtualized Layer 2 Networks over Layer 3
Networks", RFC 7348, DOI 10.17487/RFC7348, August 2014,
<http://www.rfc-editor.org/info/rfc7348>.
[idrtun] Rosen, E., Ed., Patel, K., and G. Van de Velde, "Using the
BGP Tunnel Encapsulation Attribute without the BGP
Encapsulation SAFI", 2015.
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Authors' Addresses
Paul Quinn
Cisco Systems, Inc.
Email: paulq@cisco.com
Rajeev Manur
Broadcom
Email: rmanur@broadcom.com
Larry Kreeger
Cisco Systems, Inc.
Email: kreeger@cisco.com
Darrel Lewis
Cisco Systems, Inc.
Email: darlewis@cisco.com
Fabio Maino
Cisco Systems, Inc.
Email: fmaino@cisco.com
Michael Smith
Cisco Systems, Inc.
Email: michsmit@cisco.com
Puneet Agarwal
Innovium, Inc
Email: puneet@acm.org
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Lucy Yong
Huawei USA
Email: lucy.yong@huawei.com
Xiaohu Xu
Huawei Technologies
Email: xuxiaohu@huawei.com
Uri Elzur
Intel
Email: uri.elzur@intel.com
Pankaj Garg
Microsoft
Email: Garg.Pankaj@microsoft.com
David Melman
Marvell
Email: davidme@marvell.com
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