Internet DRAFT - draft-ietf-idr-sdwan-edge-discovery
draft-ietf-idr-sdwan-edge-discovery
Network Working Group L. Dunbar
Internet-Draft Futurewei
Intended status: Standards Track K. Majumdar
Expires: 16 April 2024 Microsoft Azure
S. Hares
Hickory Hill Consulting
R. Raszuk
Arrcus
V. Kasiviswanathan
Arista
14 October 2023
BGP UPDATE for SD-WAN Edge Discovery
draft-ietf-idr-sdwan-edge-discovery-12
Abstract
The document describes the encoding of BGP UPDATE messages for the
SD-WAN edge node property discovery.
In the context of this document, BGP Route Reflector (RR) is the
component of the SD-WAN Controller that receives the BGP UPDATE from
SD-WAN edges and in turns propagates the information to the intended
peers that are authorized to communicate via the SD-WAN overlay
network.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119] [RFC8174]
when, and only when, they appear in all capitals, as shown here.
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 https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
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This Internet-Draft will expire on 16 April 2024.
Copyright Notice
Copyright (c) 2023 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 (https://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
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions used in this document . . . . . . . . . . . . . . 3
3. Framework of SD-WAN Edge Discovery . . . . . . . . . . . . . 4
3.1. The Objectives of SD-WAN Edge Discovery . . . . . . . . . 4
3.2. Comparing with Pure IPsec VPN . . . . . . . . . . . . . . 5
3.3. Client Route UPDATE and SD-WAN Tunnel UPDATE . . . . . . 6
3.4. Edge Node Discovery . . . . . . . . . . . . . . . . . . . 8
4. Constrained propagation of BGP UPDATE . . . . . . . . . . . . 9
4.1. SD-WAN Segmentation, Virtual Topology and Client VPN . . 9
4.2. 4.2. Constrained Propagation of Edge Capability . . . . 10
5. Client Route UPDATE . . . . . . . . . . . . . . . . . . . . . 11
5.1. SD-WAN VPN ID in Client Route Update . . . . . . . . . . 12
5.2. SD-WAN VPN ID in Data Plane . . . . . . . . . . . . . . . 12
6. SD-WAN Underlay UPDATE . . . . . . . . . . . . . . . . . . . 12
6.1. NLRI for SD-WAN Underlay Tunnel Update . . . . . . . . . 12
6.2. SD-WAN-Hybrid Tunnel Encoding . . . . . . . . . . . . . . 14
6.3. IPsec-SA-ID Sub-TLV . . . . . . . . . . . . . . . . . . . 14
6.4. Extended Port Attribute Sub-TLV . . . . . . . . . . . . . 15
6.5. Extended SubSub-TLV . . . . . . . . . . . . . . . . . . . 18
6.5.1. Underlay Network Transport SubSub-TLV . . . . . . . . 18
7. IPsec SA Property Sub-TLVs . . . . . . . . . . . . . . . . . 19
7.1. IPsec SA Nonce Sub-TLV . . . . . . . . . . . . . . . . . 19
7.2. IPsec Public Key Sub-TLV . . . . . . . . . . . . . . . . 20
7.3. IPsec SA Proposal Sub-TLV . . . . . . . . . . . . . . . . 21
7.4. Simplified IPsec SA sub-TLV . . . . . . . . . . . . . . . 21
8. Error and Mismatch Handling . . . . . . . . . . . . . . . . . 23
8.1. Color Mismatch . . . . . . . . . . . . . . . . . . . . . 23
8.2. IPsec Attributes Mismatch . . . . . . . . . . . . . . . . 24
9. SD-WAN BGP UPDATE Encoding Examples . . . . . . . . . . . . . 25
9.1. Encoding example of WAN Port properties . . . . . . . . . 25
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9.2. Encoding example of IPsec SA terminated at the C-PE2 . . 26
9.3. Encoding example of using IPsec-SA-ID Sub-TLV . . . . . . 26
10. Manageability Considerations . . . . . . . . . . . . . . . . 27
11. Security Considerations . . . . . . . . . . . . . . . . . . . 27
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28
12.1. Hybrid (SD-WAN) Overlay SAFI . . . . . . . . . . . . . . 28
12.2. Tunnel Encapsulation Attribute Type . . . . . . . . . . 28
12.3. Tunnel Encapsulation Attribute Sub-TLV Types . . . . . . 28
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 28
13.1. Normative References . . . . . . . . . . . . . . . . . . 28
13.2. Informative References . . . . . . . . . . . . . . . . . 30
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 31
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 31
1. Introduction
[SD-WAN-BGP-USAGE] illustrates how BGP [RFC4271] is used as a control
plane for a SD-WAN network. SD-WAN network refers to a policy-driven
network over multiple heterogeneous underlay networks to get better
WAN bandwidth management, visibility, and control.
The document describes BGP UPDATE messages for an SD-WAN edge node to
advertise its properties to its RR which then propagates that
information to the authorized peers.
2. Conventions used in this document
The following acronyms and terms are used in this document:
Cloud DC: Off-Premises Data Centers that usually host applications
and workload owned by different organizations or tenants.
Controller: Used interchangeably with SD-WAN controller to manage
SD-WAN overlay path creation/deletion and monitor the path
conditions between sites
CPE: Customer (Edge) Premises Equipment
CPE-Based VPN: Virtual Private Secure network formed among CPEs.
This is to differentiate such VPNs from most commonly used PE-
based VPNs discussed in [RFC4364].
MP-NLRI: Multi-Protocol Network Layer Reachability Information
[MP_REACH_NLRI] Path Attribute defined in [RFC4760]
RR: Route Reflector
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SD-WAN: An overlay connectivity service that optimizes transport of
IP Packets over one or more Underlay Connectivity Services by
recognizing applications (Application Flows) and determining
forwarding behavior by applying Policies to them. [MEF-70.1]
SD-WAN Endpoint: can be the SD-WAN edge node address, a WAN port
address (logical or physical) of a SD-WAN edge node, or a client
port address.
VPN: Virtual Private Network
VRF: VPN Routing and Forwarding instance
WAN: Wide Area Network
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC8174] when, and only when, they appear in all capitals, as
shown here.
3. Framework of SD-WAN Edge Discovery
3.1. The Objectives of SD-WAN Edge Discovery
The objectives of SD-WAN edge discovery for an SD-WAN edge node are:
to discover its authorized peers and their associated properties in
order to establish secure overlay tunnels [Net2Cloud]. The
attributes to be propagated includes:
* the SD-WAN (client) VPNs information,
* the attached routes under the SD-WAN VPNs, and
* the properties of the underlay networks over which the client
routes can be carried, and potentially more.
Some SD-WAN peers are connected by both trusted VPNs and untrusted
public networks. Some SD-WAN peers are connected only by untrusted
public networks. For the traffic over untrusted networks, IPsec
Security Associations (IPsec SA) must be established and maintained.
If an edge node has network ports behind a NAT, the NAT properties
need to be discovered by the authorized SD-WAN peers.
Like any VPN networks, the attached client routes belonging to
specific SD-WAN VPNs can only be exchanged with the SD-WAN peer nodes
authorized to communicate.
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3.2. Comparing with Pure IPsec VPN
A pure IPsec VPN has IPsec tunnels connecting all edge nodes over
public networks. Therefore, it requires stringent authentication and
authorization (i.e., IKE Phase 1) before other properties of IPsec SA
can be exchanged. The IPsec Security Association (SA) between two
untrusted nodes typically requires the following configurations and
message exchanges:
IPsec IKEV2: messages sent to authenticate with each other.
Establish IPsec SA : requires the following set-up
- Local key configuration,
- Setting the Remote Peer address (such as 192.10.0.10 -
172.0.01
- Information from IKEv2 Proposal directly sent to peer:
(Encryption method, Integrity sha512, etc.)
- Transform set.
Attached client prefixes discovery: which is achieved by:
- Running routing protocol within each IPsec SA.
- If multiple IPsec SAs between two peer nodes are established
to achieve load sharing, each IPsec tunnel needs to run its
own routing protocol to exchange client routes attached to
the edges.
Set-up Access List or Traffic Selector: such as Permit Local-IP1,
Remote-IP2, and other parameters.
In a BGP-controlled SD-WAN network over hybrid MPLS VPN and public
internet underlay networks, all edge nodes and RRs are already
connected by private secure paths. The RRs have the policies to
manage the authentication of all peer nodes. More importantly, when
an edge node needs to establish multiple IPsec tunnels to many edge
nodes, all the management information can be multiplexed into the
secure management tunnel between RR and the edge node. Therefore,
the amount of authentication in a BGP-Controlled SD-WAN network can
be significantly reduced.
Client VPNs are configured via VRFs, just like the configuration of
the existing MPLS VPN. The IPsec equivalent traffic selectors for
local and remote routes are achieved by importing/exporting VPN Route
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Targets. The binding of client routes to IPsec SA is dictated by
policies. As a result, the IPsec configuration for a BGP controlled
SD-WAN (with mixed MPLS VPN) can be simplified in the following
manner:
* The SD-WAN controller has the authority to authenticate edges and
peers so the Remote Peer association is controlled by the SD-WAN
Controller (RR).
* The IKEv2 proposals (including the IPsec Transform set) can be
sent directly to peers, or incorporated in a BGP UPDATE.
* The BGP UPDATE announces the client route reachability for all
permitted parallel tunnels/paths.
* Importing/exporting Route Targets under each client VPN (VRF)
achieves the traffic selection (or permission) among clients'
routes attached to multiple edge nodes.
Note that with this method there is no need to run multiple routing
protocols in each IPsec tunnel.
3.3. Client Route UPDATE and SD-WAN Tunnel UPDATE
As described in [SD-WAN-BGP-USAGE], two separate BGP UPDATE messages
are used for SD-WAN Edge Discovery:
- Client routes BGP UPDATE:
This UPDATE is precisely the same as the BGP VPN client route
UPDATE. It uses the Encapsulation Extended Community and the
Color Extended Community to link with the SD-WAN Tunnels UPDATE
Message as specified in section 8 of [RFC9012].
A new Tunnel Type (SD-WAN-Hybrid) is added and used by the
Encapsulation Extended Community or the Tunnel-Encap Path
Attribute [RFC9012] to indicate mixed underlay networks.
- SD-WAN UPDATE:
This UPDATE is for an edge node to advertise the properties of
directly attached underlay networks, including the NAT
information, pre-configured IPsec SA identifiers, and/or the
underlay network specific information. This UPDATE can also
include the detailed IPsec SA attributes, such as keys, nonce,
encryption algorithms, etc.
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In the following figure, four overlay paths between C-PE1 and C-PE2
are established for illustration purpose. More overlay paths are
possible. One physical port on C-PE2 can terminate multiple overlay
paths from different ports on C-PE1.
a) MPLS-in-GRE path;
b) node-based IPsec tunnel [2.2.2.2 - 1.1.1.1]. As C-PE2 has two
public internet facing WAN ports, either of those two WAN port IP
addresses can be the outer destination address of the IPsec
encapsulated data packets;
c) port-based IPsec tunnel [192.0.0.1 - 192.10.0.10]; and
d) port-based IPsec tunnel [172.0.0.1 - 160.0.0.1].
+---+
+--------------|RR |----------+
/ Untrusted +-+-+ \
/ \
/ \
+---------+ MPLS Path +-------+
11.1.1.x| C-PE1 A1-------------------------------B1 C-PE2 |10.1.1.x
| | | |
21.1.1.x| A2(192.10.0.10)------( 192.0.0.1)B2 |20.1.1.x
| | | |
| Addr A3(160.0.0.1) --------(170.0.0.1)B3 Addr |
| 1.1.1.1 | |2.2.2.2|
+---------+ +-------+
Figure 1: Hybrid SD-WAN
C-PE2 advertises the attached client routes as below:
* Client Route UPDATE:
- Extended community: RT for SD-WAN VPN 1
- NLRI: AFI=IPv4/IPv6 and SAFI = VPN
- Prefix: 10.1.1.x; 20.1.1.x
- NextHop: 2.2.2.2 (C-PE2)
- Encapsulation Extended Community: tunnel-type=SD-WAN-Hybrid
- Color Extended Community: Site-identifier
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* SD-WAN UPDATE:
- C-PE2 can use the following Update messages to advertise the
properties of Internet facing ports 192.0.0.1 and 170.0.0.1,
and their associated IPsec SA related parameters.
- Update #1 for the properties associated with the WAN port
192.0.0.1, such as the NAT properties, the underlay network
properties, etc. (Details in Section 9.1).
- Update #2 for the properties associated with the WAN port
170.0.0.1 associated properties. (Details in Section 9.1).
- Update #3 for IPsec parameters associated with IPsec tunnel
terminated at the Node level (2.2.2.2), such as the supported
encryption methods, public keys, etc. (Details in
Section 9.2).
3.4. Edge Node Discovery
The basic scheme of SD-WAN edge node discovery using BGP consists of
the following:
* Secure connection to a SD-WAN controller (in this context the RR
):
- For an SD-WAN edge with both MPLS and IPsec paths, the edge
node should already have a secure connection to its controller
(the RR in this context). For an SD-WAN edge that is only
accessible via Internet, the SD-WAN edge, upon power-up,
establishes a secure tunnel (such as TLS or SSL) with the SD-
WAN central controller whose address is preconfigured on the
edge node. The central controller informs the edge node of its
local RR. The edge node then establishes a transport layer
secure session with the RR (such as TLS or SSL).
* The Edge node will advertise its own properties to its designated
RR via the secure connection.
* The RR propagates the received information to the authorized
peers.
* The authorized peers can establish the secure data channels
(IPsec) and exchange more information among each other.
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For an SD-WAN deployment with multiple RRs, it is assumed that there
are secure connections among those RRs. How secure connections are
established among those RRs is out of the scope of this document.
The existing BGP UPDATE propagation mechanisms control the edge
properties propagation among the RRs.
For some environments where the communication to RR is highly
secured, [RFC9016] IKE-less can be deployed to simplify IPsec SA
establishment among edge nodes.
4. Constrained propagation of BGP UPDATE
4.1. SD-WAN Segmentation, Virtual Topology and Client VPN
In SD-WAN deployment, SD-WAN Segmentation is a frequently used term,
referring to partitioning a network into multiple subnetworks, just
like MPLS VPNs. SD-WAN Segmentation is achieved by creating SD-WAN
virtual topologies and SD-WAN VPNs. An SD-WAN virtual topology
consists of a set of edge nodes and the tunnels (a.k.a. underlay
paths), including both IPsec tunnels and/or MPLS VPN tunnels,
interconnecting those edge nodes.
An SD-WAN VPN is configured in the same way as the VRFs of an MPLS
VPN. One SD-WAN client VPN can be mapped to multiple SD-WAN virtual
topologies. SD-WAN Controller governs the policies of mapping a
client VPN to SD-WAN virtual topologies.
Each SD-WAN edge node may need to support multiple VPNs. Route
Target is used to differentiate the SD-WAN VPNs. For example, in the
picture below, the Payment-Flow on C-PE2 is only mapped to the
virtual topology of C-PEs to/from Payment Gateway, whereas other
flows can be mapped to a multipoint-to-multipoint virtual topology.
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+---+
+--------------|RR |----------+
/ Untrusted +-+-+ \
/ \
/ \
+---------+ MPLS Path +-------+
11.1.1.x| C-PE1 A1-------------------------------B1 C-PE2 |10.1.1.x
| | | |
21.1.1.x| A2(192.10.0.10)------( 192.0.0.1)B2 |20.1.1.x
| | | |
| Addr A3(160.0.0.1) --------(170.0.0.1)B3 Addr |11.2.2.x
| 1.1.1.1 | / |2.2.2.2|
+---------+ / +-------+
\ /
\ /PaymentFlow
\ /
\ +----+----+
+---------------| payment |
| Gateway |
+---------+
Figure 2: SD-WAN Virtual Topology and VPN
4.2. 4.2. Constrained Propagation of Edge Capability
BGP has a built-in mechanism [RFC4684] to dynamically achieve the
constrained distribution of edge information. In a nutshell, an SD-
WAN edge sends RT Constraint (RTC) NLRI to the RR for the RR to
install an outbound route filter, as shown in the figure below:
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RT Constraint RT constraint
NLRI={SD-WAN#1, SD-WAN#2} NLRI={SD-WAN#1, SD-WAN#3}
-----> +---+ <-----------
+--------------------|RR1|------------------+
| Outbound Filter +---+ Outbound Filter |
| Permit SD-WAN#1,#2 Permit SD-WAN#1,#3|
| Deny all Deny all |
| <------- ---------> |
| |
+-----+---+ MPLS Path +-----+-+
11.1.1.x| C-PE1 A1-------------------------------B1 C-PE2 |10.1.1.x
| | | |
21.1.1.x| A2(192.10.0.10)------( 192.0.0.1)B2 |20.1.1.x
| | | |
| Addr A3(160.0.0.1) --------(170.0.0.1)B3 Addr |
| 1.1.1.1 | |2.2.2.2|
+---------+ +-------+
SD-WAN VPN #1 SD-WAN VPN #1
SD-WAN VPN #2 SD-WAN VPN #3
Figure 3: Constraint propagation of Edge Property
However, a SD-WAN overlay network can span across untrusted networks,
RR cannot trust the RT Constraint (RTC) NLRI BGP UPDATE from any
nodes. RR can only process the RTC NLRI from authorized peers for a
SD-WAN VPN.
It is out of the scope of this document on how RR is configured with
the policies to filter out unauthorized nodes for specific SD-WAN
VPNs.
When the RR receives BGP UPDATE from an edge node, it propagates the
received UPDATE message to the nodes that are in the Outbound Route
filter for the specific SD-WAN VPN.
5. Client Route UPDATE
The SD-WAN network's Client Route UPDATE message is the same as the
L3 VPN or EVPN client route UDPATE message. The SD-WAN Client Route
UPDATE message uses the Encapsulation Extended Community and the
Color Extended Community to link with the SD-WAN Underlay UPDATE
Message.
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5.1. SD-WAN VPN ID in Client Route Update
An SD-WAN VPN is same as a client VPN in a BGP controlled SD-WAN
network. The Route Target Extended Community should be included in a
Client Route UPDATE message to differentiate the client routes from
routes belonging to other VPNs.
5.2. SD-WAN VPN ID in Data Plane
For an SD-WAN edge node which can be reached by both MPLS and IPsec
paths, the client packets reached by MPLS network will be encoded
with the MPLS Labels based on the scheme specified by [RFC8277].
For GRE Encapsulation within an IPsec tunnel, the GRE key field can
be used to carry the SD-WAN VPN ID. For network virtual overlay
(VxLAN, GENEVE, etc.) encapsulation within the IPsec tunnel, the
Virtual Network Identifier (VNI) field is used to carry the SD-WAN
VPN ID.
6. SD-WAN Underlay UPDATE
The hybrid underlay tunnel UPDATE is to advertise the detailed
properties associated with the public facing WAN ports and IPsec
tunnels. The Edge node will advertise its own properties to its
designated RR via the secure connection.
6.1. NLRI for SD-WAN Underlay Tunnel Update
A new NLRI SAFI[RFC5521](SD-WAN SAFI=74)is introduced within the
MP_REACH_NLRI Path Attribute of RFC4760 for advertising the detailed
properties of the SD-WAN tunnels terminated at the edge node:
+------------------+
| Route Type | 2 octet
+------------------+
| Length | 2 Octet
+------------------+
| Type Specific |
~ Value (Variable) ~
| |
+------------------+
Figure 4: SD-WAN NLRI
Where
Route (NLRI) Type: 2 octet value to define the encoding of the rest
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of the SD-WAN the NLRI.
Length: 2 octets of length expressed in bits as defined in
[RFC4760].
This document defines the following SD-WAN Route type:
NLRI Route-Type= 1: For advertising the detailed properties of the
SD-WAN tunnels terminated at the edge, where the transport network
port can be uniquely identified by a tuple of three values (Port-
Local-ID, SD-WAN-Color, SD-WAN-Node-ID). The SD-WAN NLRI Route-
Type =1 has the following encoding:
+------------------+
| Route Type = 1 | 2 octet
+------------------+
| Length | 2 Octet
+------------------+
| Port-Local-ID | 4 octets
+------------------+
| SD-WAN-Color | 4 octets
+------------------+
| SD-WAN-Node-ID | 4 or 16 octets
+------------------+
Figure 5: SD-WAN NLRI Route Type 1
Port local ID: SD-WAN edge node Port identifier, which is locally
significant. If the SD-WAN NLRI applies to multiple WAN ports,
this field is NULL.
SD-WAN-Color: to represent a group of tunnels, which correlate with
the Color-Extended-community included in the client routes UPDATE.
When a client route can be reached by multiple SD-WAN edges co-
located at one site, the SD-WAN- Color can represent a group of
tunnels terminated at those SD-WAN edges co-located at the site,
which effectively represent the site.
SD-WAN Node ID: The node's IPv4 or IPv6 address.
Route Type values outside of 1 are out of scope for this document.
The Route Type allows for other existing SD-WAN applications to use
this basic format.
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6.2. SD-WAN-Hybrid Tunnel Encoding
A new BGP Tunnel-Type=SD-WAN-Hybrid (code point 25) is to indicate
hybrid underlay tunnels.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tunnel-Type=25(SD-WAN-Hybrid )| Length (2 Octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-TLVs |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: SD-WAN Hybrid Value Field
6.3. IPsec-SA-ID Sub-TLV
IPsec-SA-ID Sub-TLV within the Hybrid Underlay Tunnel UPDATE
indicates one or more pre-established IPsec SAs by using their
identifiers, instead of listing all the detailed attributes of the
IPsec SAs.
Using an IPsec-SA-ID Sub-TLV not only greatly reduces the size of BGP
UPDATE messages, but also allows the pairwise IPsec rekeying process
to be performed independently.
The following is the structure of the IPsec-SA-ID sub-TLV:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Type=64 (IPsec-SA-ID subTLV) | Length (2 Octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPsec SA Identifier #1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPsec SA Identifier #2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: IPsec-SA-ID Sub-TLV
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6.4. Extended Port Attribute Sub-TLV
Extended Port Attribute Sub-TLV is to advertise the properties
associated with a public Internet-facing WAN port that might be
behind NAT. An SD-WAN edge node can query a STUN Server (Session
Traversal of UDP through Network address translation [RFC8489]) to
get the NAT properties, including the public IP address and the
Public Port number, to pass to its peers.
The location of a NAT device can be:
* Only the initiator is behind a NAT device. Multiple initiators
can be behind separate NAT devices. Initiators can also connect
to the responder through multiple NAT devices.
* Only the responder is behind a NAT device.
* Both the initiator and the responder are behind a NAT device.
The initiator's address and/or responder's address can be dynamically
assigned by an ISP or when their connection crosses a dynamic NAT
device that allocates addresses from a dynamic address pool.
As one SD-WAN edge can connect to multiple peers, the pair-wise NAT
exchange as IPsec's IKE[RFC7296] is not efficient. In the BGP
Controlled SD-WAN, NAT properties for a WAN port are encoded in the
Extended Port Attribute sub-TLV, which the following format:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Type=65(extPort| ExtPort Length| Reserved |I|O|R|R|R|R|R|R|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NAT Type | Encap-Type |Trans networkID| RD ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local IP Address |
32-bits for IPv4, 128-bits for Ipv6
~~~~~~~~~~~~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Public IP |
32-bits for IPv4, 128-bits for Ipv6
~~~~~~~~~~~~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Public Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended SubSub-TLV |
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8: Extended Port Attribute Sub-TLV
Where:
* Extended Port Attribute Type (=65): indicating it is the Extended
Port Attribute SubTLV
* ExtPort Length: the length of the subTLV.
* Flags:
- I bit (CPE port address or Inner address scheme):
o If set to 0, indicate the inner (private) address is IPv4.
o If set to 1, indicates the inner address is IPv6.
- O bit (Outer address scheme):
o If set to 0, indicate the inner (private) address is IPv4.
o If set to 1, indicates the inner address is IPv6.
- R bits: reserved for future use. Must be set to 0 now:
* NAT Type: the NAT type can be one of the following values:
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- 1: without NAT ;
- 2: 1-to-1 static NAT;
- 3: Full Cone;
- 4: Restricted Cone;
- 5: Port Restricted Cone;
- 6: Symmetric; or
- 7: Unknown (i.e. no response from the STUN server).
* Encap-Type: the supported encapsulation types for the port.
- Encap-Type=1: GRE;
- Encap-Type=2: VxLAN;
Notes:
- The Encap-Type inside the Extended Port Attribute Sub-TLV is
different from the RFC9012's BGP-Tunnel-Encapsulation type
(https://www.iana.org/assignments/bgp-tunnel-encapsulation/bgp-
tunnel-encapsulation.xhtml#tunnel-types). The Extended Port
Attribute Sub-TLV is a subTLV attached to the Tunnel Type TLV
(the BGP-Tunnel-Type = 25 for the SD-WAN Hybrid tunnels). The
port can indicate the specific encapsulations, such as:
- If the IPsec-SA-ID subTLV or the IPsec SA detailed
subTLVs(Nonce/publicKey/Proposal) are included in the SD-WAN-
Hybrid tunnel, the Encap-Type indicates the encapsulation type
within the IPsec payload.
- If the IPsec SA subTLVs are not included in the SD-WAN-Hybrid
Tunnel, the Encap-Type indicates the encapsulation of the
payload without IPsec encryption.
* Transport Network ID: Central Controller assigns a global unique
ID to each transport network.
* RD ID: Routing Domain ID, need to be globally unique.
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- Some SD-WAN deployment might have multiple levels, zones, or
regions that are represented as routing domains. Policies can
govern if tunnels can be established across domains. E.g., a
hub node can establish tunnels with different domains; but the
spoke nodes cannot establish tunnels with nodes in different
domains.
* Local IP: The local (or private) IP address of the WAN port.
* Local Port: used by Remote SD-WAN edge node for establishing IPsec
to this specific port.
* Public IP: The IP address after the NAT. If NAT is not used, this
field is set to NULL.
* Public Port: The Port after the NAT. If NAT is not used, this
field is set to NULL.
* Extended SubSub-TLV: for carrying additional information about the
underlay networks.
6.5. Extended SubSub-TLV
Two types of the Extended SubSub-TLVs are specified in this document:
Underlay Network Transport SubSub-TLV and the underlay Geo Location
SubSub-TLV.
6.5.1. Underlay Network Transport SubSub-TLV
The Underlay Network Transport SubSub-TLV is an optional Sub-TLV to
carry the WAN port connection types and bandwidth, such as LTE, DSL,
Ethernet, etc.
The format of this Sub-TLV is as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| UnderlayType | Length | Flag | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Connection Type| Port Type | Port Speed |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 9: Underlay Network SubSub-TLV
Where:
Underlay Network Properties: sub Type=66
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Length: always 6 bytes
Flag: a 1 octet value.
Reserved: 1 octet of reserved bits. It SHOULD be set to zero on
transmission and MUST be ignored on receipt.
Connection Type: are listed below as:
* 1 = Wired
* 2 = WIFI
* 3 = LTE
* 4 = 5G
Port Type: Port type define as follows:
* 1 = Ethernet
* 2 = Fiber Cable
* 3 = Coax Cable
* 4 = Cellular
Port Speed: The port seed is defined as 2 octet value. The values
are defined as Gigabit speed. For example, a value of 1 would
mean 1 gigabit.
7. IPsec SA Property Sub-TLVs
This section describes the detailed IPsec SA properties sub-TLVs.
When the IPsec SA properties are associated with the node, any of the
node's WAN ports can be the outer destination address of the IPsec
encapsulated data packets.
7.1. IPsec SA Nonce Sub-TLV
The Nonce Sub-TLV is based on the Base DIM sub-TLV as described the
Section 10.1 of [SECURE-EVPN]. The following fields are removed
because:
- the Originator ID is same as the Node-ID in the SD-WAN NLRI,
- the Tenant ID and Subnet ID are represented by the SD-WAN VPN ID
in the Client UPDATE.
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The format of this Sub-TLV is as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ID Length | Nonce Length |I| Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Rekey |
| Counter |
+---------------------------------------------------------------+
| IPsec SA Identifier |
+---------------------------------------------------------------+
| |
~ Nonce Data ~
| |
+---------------------------------------------------------------+
Figure 10: IPsec SA Nouce Sub-TLV
where:
IPsec SA ID - The 4 bytes IPSec SA ID is to differentiate multiple
IPsec SAs terminated at the edge.
- The IPsec SA ID can be used in the IPsec-SA-ID subTLV of a
different BGP UPDATE message to refer to all the values carried
in the IPsec Public Key SubTLV and the IPsec SA Proposal Sub-
TLV that are in the same BGP UPDATE message as the IPsec SA
Nonce sub-TLV.
7.2. IPsec Public Key Sub-TLV
The IPsec Public Key Sub-TLV is derived from the Key Exchange Sub-TLV
described in [SECURE-EVPN] with an addition of Duration filed to
define the IPSec SA life span. The edge nodes would pick the
shortest duration value advertised by the peers.
The format of this Sub-TLV is as follows:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Diffie-Hellman Group Num | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Key Exchange Data ~
| |
+---------------------------------------------------------------+
| Duration |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 11: IPsec SA Public Key Sub-TLV
7.3. IPsec SA Proposal Sub-TLV
The IPsec SA Proposal Sub-TLV is to indicate the number of Transform
Sub-TLVs. This Sub-TLV aligns with the sub-TLV structure from
[SECURE-EVPN].
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transform Attr Length |Transform Type | Reserved. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transform ID | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Transform Attributes ~
| |
+---------------------------------------------------------------+
Figure 12: IPsec SA Proposal Sub-TLV
The Transform Type and the Transform Attributes Sub-sub-TLV are taken
from the section 3.3.2 and 3.3.5 of RFC7296, respectively.
7.4. Simplified IPsec SA sub-TLV
For a simple SD-WAN network with edge nodes supporting only a few
pre-defined encryption algorithms, a simple IPsec sub-TLV can be used
to encode the pre-defined algorithms, as below:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|IPsec-simType |IPsecSA Length | Flag |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transform | Mode | AH algorithms |ESP algorithms |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ReKey Counter (SPI) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| key1 length | Key 1 ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| key2 length | Key 2 ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| key-i length | Nonce ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Duration |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 13: Siplified IPsec SA Sub-TLV
Where:
IPsec-SimType=70: indicate the simplified IPsec SA attributes.
IPsec-SA subTLV Length (2 Byte): 25 (or more).
Flags: 1 octet of flags. None are defined at this stage. Flags
SHOULD be set to zero on transmission and MUST be ignored on
receipt.
Transform (1 Byte):
* Transform = 1 means AH,
* Transform = 2 means ESP, or
* Transform = 3 means AH+ESP.
IPsec Mode (1 byte):
* Mode = 1 indicates that the Tunnel Mode is used.
* Mode = 2 indicates that the Transport mode is used.
AH algorithms (1 byte): AH authentication algorithms supported. The
values are specified by [IANA-AH]. Each SD-WAN edge node can
support multiple authentication algorithms; send to its peers to
negotiate the strongest one.
ESP algorithms (1 byte): the ESP algorithms supported. Its values
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are specified by [IANA-ESP]. One SD-WAN edge node can support
multiple ESP algorithms and send them to its peers to negotiate
the strongest one. The default algorithm is AES-256.
When a node supports multiple authentication algorithms, the
initial UPDATE needs to include the "Transform Sub-TLV"
described by [SECURE-EVPN] to describe all of the algorithms
supported by the node.
Rekey Counter (Security Parameter Index)): 4 bytes
Public Key: IPsec public key
Nonce: IPsec Nonce
Duration: SA life span.
8. Error and Mismatch Handling
8.1. Color Mismatch
When an SD-WAN edge receives a client route BGP UPDATE from a peer
with a color that does not match with any of the tunnels advertised
by the peer, the client route UPDATE should be ignored, and an error
message (e.g., Syslog) should be generated to its management system
per[RFC7606].
For example, for two peers, PA and PB, both PA and PB will first
advertise their SD-WAN properties (i.e., tunnel properties). Say PA
advertises two SD-WAN tunnels (Red and Green), and PB advertises two
SD-WAN tunnels (Yellow and Purple). PB should report a mismatch
error message when PB receives a Client Update from PA with a color
NOT Red or Green. PA should report a Mismatch Error when PA receives
a Client Update from PB with a color that is not Yellow and Purple.
Upon receiving a Tunnel Update that includes the IPsec-SA-ID subTLV
from a peer, the BGP node should report Mismatch error if the IPsec
SA has not been established yet.
Moreover, if the encap-Types, in the Extended Port Attributes Sub-
TLV, in the received SDWAN update is not supported by the local
ports, the corresponding ports between the remote edge and local edge
will not establish an overlay tunnel. Overlay tunnels would only be
established between two ports belonging to different edges, if their
attributes are compatible. For instance, the encap Types should
match. Policies and configurations outside the scope of this
document could allow for mismatched attributes to be present and
allow establishing overlay tunnels.
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8.2. IPsec Attributes Mismatch
Each C-PE device advertises a SD-WAN SAFI Underlay NLRI to the other
C-PE devices via a BGP Route Reflector to establish pairwise SAs
between itself and every other remote C-PEs. During the SAFI NLRI
advertisement, the BGP originator would include either simple IPSec
Security Association properties defined in IPSec SA Sub-TLV based on
IPSec-SA-Type = 1 or full-set of IPSec Sub-TLVs including Nonce,
Public Key, Proposal and number of Transform Sub-TLVs based on IPSec-
SA-Type = 2.
The C-PE devices compare the IPSec SA attributes between the local
and remote WAN ports. If there is a match on the SA Attributes
between the two ports, the IPSec Tunnel is established.
The C-PE devices would not try to negotiate the base IPSec-SA
parameters between the local and the remote ports in the case of
simple IPSec SA exchange or the Transform sets between local and
remote ports if there is a mismatch on the Transform sets in the case
of full-set of IPSec SA Sub-TLVs.
Here is an example of using Figure 1 in Section 3 to establish an
IPsec Tunnel between C-PE1 and C-PE2 WAN Ports A2 and B2 (A2:
192.10.0.10 - B2:192.0.0.1).
C-PE1 needs to advertise the following attributes for establishing
the IPsec SA:
* NextHop: 192.10.0.10
* SD-WAN Node ID
* SD-WAN-Site-ID
* Tunnel Encap Attr (Type=SD-WAN) -
- Extended Port Attribute Sub-TLV
o Transport SubSubTLV - with information on ISP3.
- Transport-Sub-TLV for detailed information about the ISP3
- IPsec SA Nonce Sub-TLV,
- IPsec SA Public Key Sub-TLV,
- Proposal Sub-TLV with Num Transforms = 1
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- {Transforms Sub-TLV - Trans 1}
C-PE2 needs to advertise the following attributes for establishing
IPsec SA:
NH: 192.0.0.1
SD-WAN Node ID: (value)
SD-WAN-Site-ID: (value)
Tunnel Encap Attr (Type=SD-WAN)
* Extended Port Attribute Sub-TLV
- Transport SubSubTLV - with information on ISP1.
* IPsec SA Nonce Sub-TLV,
* IPsec SA Public Key Sub-TLV,
* Proposal Sub-TLV with Num Transforms = 1
* {Transforms Sub-TLV - Trans 2}
As there is no matching transform between the WAN ports A2 and B2 in
C-PE1 and C-PE2, respectively, no IPsec Tunnel will be established.
9. SD-WAN BGP UPDATE Encoding Examples
9.1. Encoding example of WAN Port properties
The C-PE2 of Figure 1 can send the following SD-WAN UPDATE messages
to advertise the properties associated with WAN Port 192.0.0.1 and
WAN Port 170.0.0.1, respectively:
SD-WAN NLRI: AFI=IPv4/IPv6 and SAFI = SD-WAN
* Color match with the Client route UPDATE's Color Extended
Community[RFC4360]
* local port id for WAN port 192.0.0.1
* Node-ID= 2.2.2.2 (C-PE2)
Tunnel-Type: Hybrid-SD-WAN
Extended-Port-SubTLV: for 192.0.0.1
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SD-WAN NLRI: AFI=IPv4/IPv6 and SAFI = SD-WAN
* Color match with the Client route UPDATE's Color Extended
Community
* local port id for WAN port 170.0.0.1
* Node-ID= 2.2.2.2 (C-PE2)
Tunnel-Type: Hybrid-SD-WAN
Extended-Port-SubTLV for 170.0.0.1
9.2. Encoding example of IPsec SA terminated at the C-PE2
The C-PE2 of the Figure 1 can send the following SD-WAN UPDATE
messages to advertise node level IPsec SA:
SD-WAN NLRI: AFI=IPv4/IPv6 and SAFI = SD-WAN
* Color match with the Client route UPDATE's Color Extended
Community
* Port-ID=0
* Node-ID= 2.2.2.2 (C-PE2)
Tunnel-Type: Hybrid-SD-WAN
IPsec-SA-ID Sub-TLV or IPsec SA Property Sub-TLVs
9.3. Encoding example of using IPsec-SA-ID Sub-TLV
Here is an encoding example of four IPsec SAs terminated at the same
node.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tunnel-Type =SD-WAN-Hybrid | Length = |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tunnel-end-point sub-TLV |
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| subTLV-Type = IPsec-SA-ID | Length = |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPsec SA Identifier = 1 |
+---------------------------------------------------------------+
| IPsec SA Identifier = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPsec SA Identifier = 3 |
+-------------------------------+-------------------------------+
| IPsec SA Identifier = 4 |
+---------------------------------------------------------------+
Figure 14: Encoding Example of 4 IPsec SA
The Length of the Tunnel-Type = SDDWAN-Hybrid is the sum of the
following:
* Tunnel-end-point sub-TLV total length:
* The IPsec-SA-ID Sub-TLV length
10. Manageability Considerations
Unlike MPLS VPN whose PE nodes are all controlled by the network
operators, SD-WAN edge nodes can be installed anywhere, in shopping
malls, in 3rd party Cloud DCs, etc.
It is very important to ensure that client routes advertisement from
an SD-WAN edge node are legitimate. The RR needs to drop all the BGP
Update messages from an SD-WAN edge nodes that have invalid Route
Targets.
11. Security Considerations
The document describes the encoding for SD-WAN edge nodes to
advertise its properties to their peers to its RR, which propagates
to the intended peers via untrusted networks.
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The secure propagation is achieved by secure channels, such as TLS,
SSL, or IPsec, between the SD-WAN edge nodes and the local controller
RR.
SD-WAN edge nodes might not have secure channels with the RR. In
this case, BGP connection has be established over IPsec or TLS.
12. IANA Considerations
12.1. Hybrid (SD-WAN) Overlay SAFI
IANA has assigned SAFI = 74 as the Hybrid (SD-WAN) SAFI.
12.2. Tunnel Encapsulation Attribute Type
IANA is requested to assign a type from the BGP Tunnel Encapsulation
Attribute Tunnel Types as follows [RFC8126]:
Value Description Reference
----- ------------ ---------
25 SD-WAN-Hybrid (this document)
12.3. Tunnel Encapsulation Attribute Sub-TLV Types
IANA is requested to assign the following sub-Types in the BGP Tunnel
Encapsulation Attribute Sub-TLVs registry:
Value Type Description Reference
----- ----------------------- ---------------
64 IPSEC-SA-ID Sub-TLV (Section 6.3)
65 Extended Port Property Sub-TLV (Section 6.4)
66 Underlay Transport Sub-TLV (Section 6.5)
67 IPsec SA Nonce Sub-TLV (Section 7.1)
68 IPsec Public Key Sub-TLV (Section 7.2)
69 IPsec SA Proposal Sub-TLV (Section 7.3)
70 Simplified IPsec SA sub-TLV (Section 7.4)
13. References
13.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
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[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<https://www.rfc-editor.org/info/rfc4271>.
[RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
Communities Attribute", RFC 4360, DOI 10.17487/RFC4360,
February 2006, <https://www.rfc-editor.org/info/rfc4360>.
[RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
2006, <https://www.rfc-editor.org/info/rfc4364>.
[RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
"Multiprotocol Extensions for BGP-4", RFC 4760,
DOI 10.17487/RFC4760, January 2007,
<https://www.rfc-editor.org/info/rfc4760>.
[RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
Kivinen, "Internet Key Exchange Protocol Version 2
(IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
2014, <https://www.rfc-editor.org/info/rfc7296>.
[RFC7606] Chen, E., Ed., Scudder, J., Ed., Mohapatra, P., and K.
Patel, "Revised Error Handling for BGP UPDATE Messages",
RFC 7606, DOI 10.17487/RFC7606, August 2015,
<https://www.rfc-editor.org/info/rfc7606>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8277] Rosen, E., "Using BGP to Bind MPLS Labels to Address
Prefixes", RFC 8277, DOI 10.17487/RFC8277, October 2017,
<https://www.rfc-editor.org/info/rfc8277>.
[RFC8489] Petit-Huguenin, M., Salgueiro, G., Rosenberg, J., Wing,
D., Mahy, R., and P. Matthews, "Session Traversal
Utilities for NAT (STUN)", RFC 8489, DOI 10.17487/RFC8489,
February 2020, <https://www.rfc-editor.org/info/rfc8489>.
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[RFC9012] Patel, K., Van de Velde, G., Sangli, S., and J. Scudder,
"The BGP Tunnel Encapsulation Attribute", RFC 9012,
DOI 10.17487/RFC9012, April 2021,
<https://www.rfc-editor.org/info/rfc9012>.
13.2. Informative References
[IANA-AH] IANA, "IANA-AH", <https://www.iana.org/assignments/isakmp-
registry/isakmp-registry.xhtml#isakmp-registry-9>.
[IANA-ESP] IANA, "IANA-ESP", <https://www.iana.org/assignments/
isakmp-registry/isakmp-registry.xhtml#isakmp-registry-9>.
[Net2Cloud]
L. Dunbar, A Malis, C. Jacquenet, M. Toy and K. Majumdar,
"Dynamic Networks to Hybrid Cloud DCs: Problem Statement
and Mitigation Practice", September 2023,
<https://datatracker.ietf.org/doc/draft-ietf-rtgwg-
net2cloud-problem-statement/>.
[RFC4684] Marques, P., Bonica, R., Fang, L., Martini, L., Raszuk,
R., Patel, K., and J. Guichard, "Constrained Route
Distribution for Border Gateway Protocol/MultiProtocol
Label Switching (BGP/MPLS) Internet Protocol (IP) Virtual
Private Networks (VPNs)", RFC 4684, DOI 10.17487/RFC4684,
November 2006, <https://www.rfc-editor.org/info/rfc4684>.
[RFC5521] Oki, E., Takeda, T., and A. Farrel, "Extensions to the
Path Computation Element Communication Protocol (PCEP) for
Route Exclusions", RFC 5521, DOI 10.17487/RFC5521, April
2009, <https://www.rfc-editor.org/info/rfc5521>.
[RFC9016] Varga, B., Farkas, J., Cummings, R., Jiang, Y., and D.
Fedyk, "Flow and Service Information Model for
Deterministic Networking (DetNet)", RFC 9016,
DOI 10.17487/RFC9016, March 2021,
<https://www.rfc-editor.org/info/rfc9016>.
[SD-WAN-BGP-USAGE]
L. Dunbar, A Sajassi, J Drake, and B. Najem, "BGP Usage
for SD-WAN Overlay Networks", September 2023,
<https://datatracker.ietf.org/doc/draft-ietf-bess-bgp-
sdwan-usage/>.
[SECURE-EVPN]
A Sajassi, et al, "Secure EVPN", July 2023,
<https://datatracker.ietf.org/doc/draft-ietf-bess-secure-
evpn/>.
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Appendix A. Acknowledgments
Acknowledgements to Wang Haibo, Shunwan Zhuang, Hao Weiguo, and
ShengCheng for implementation contribution; Many thanks to Yoav Nir,
Graham Bartlett, Jim Guichard, John Scudder, and Donald Eastlake for
their review and suggestions.
Contributors
Below is a list of other contributing authors:
Gyan Mishra Shunwan Zhuang Sheng Cheng Donald Eastlake
Authors' Addresses
Linda Dunbar
Futurewei
Dallas, TX,
United States of America
Email: ldunbar@futurewei.com
Kausik Majumdar
Microsoft Azure
California,
United States of America
Email: kmajumdar@microsoft.com
Susan Hares
Hickory Hill Consulting
United States of America
Email: shares@ndzh.com
Robert Raszuk
Arrcus
United States of America
Email: robert@raszuk.net
Venkit Kasiviswanathan
Arista
United States of America
Email: venkit@arista.com
Dunbar, et al. Expires 16 April 2024 [Page 31]
