Network Working Group K. Majumdar Internet Draft Microsoft Intended status: Standard L. Dunbar Expires: November 31, 2023 Futurewei V.Kasiviswanathan Arista A. Ramchandra Microsoft May 31, 2023 Multi-segment SD-WAN via Cloud DCs draft-dmk-rtgwg-multisegment-sdwan-00 Abstract The document describes the methods to optimize the stitching of multiple SD-WAN segments on transit nodes across Cloud DCs. 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), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This Internet-Draft will expire on Dec 31, 2023. xxx, et al. Expires November 31, 2023 [Page 1] Internet-Draft Multi-segment SD-WAN 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 (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction...................................................3 2. Conventions used in this document..............................3 3. Use Cases......................................................4 3.1. Multi-segment SD-WAN via Single Cloud GW..................4 3.2. Multi-segment SD-WAN via Cloud Backbone...................5 3.3. Why not use policy-based traffic steering.................6 4. Data Plane encoding for SD-WAN Transit.........................7 4.1. GENEVE header encoding....................................7 4.2. Multi-Segment SD-WAN Option Class.........................7 4.3. SD-WAN Endpoint Sub-TLV...................................8 4.4. SD-WAN Tunnel Origin Endpoint Sub-TLV.....................9 4.5. Egress GW Sub-TLV........................................10 4.6. Include-Transit Sub-TLV..................................10 4.7. Exclude-Transit Sub-TLV..................................10 5. IPsec Flow through Cloud GWs Illustration.....................10 5.1. Single Hop Cloud GW......................................11 5.2. Multi-hop Transit GWs....................................12 5.3. Data Authentication and Integrity Check by Cloud GW......14 6. Illustration of Traffic from Private VPN to IPsec Tunnel......14 7. Control Plane consideration...................................16 7.1. Control Plane for CPEs...................................16 7.2. Control Plane between CPEs and Cloud GWs.................16 8. Observability Consideration...................................17 9. Manageability Considerations..................................17 10. Security Considerations......................................17 11. IANA Considerations..........................................17 12. References...................................................17 Dunbar, et al. Expires Dec 31, 2023 [Page 2] Internet-Draft Multi-segment SD-WAN 12.1. Normative References....................................17 12.2. Informative References..................................18 13. Acknowledgments..............................................20 1. Introduction Cloud Providers support SD-WAN interconnecting enterprises' on-prem rd CPEs with the enterprises-owned applications/services and 3 party SASE services in cloud DCs. As described in [Net2Cloud], there are multiple options for enterprises to connect to Cloud DCs: - Direct Interconnect model, - Direct Interconnect model with enterprise's own virtual appliances in the Cloud, - Indirect Interconnect model via SD-WAN paths, and - Managed Hybrid WAN model using Enterprise's existing VPN connections. For the enterprise branches that have private VPN circuits interconnecting with a Cloud GW via IXP (Internet eXchange Point), the enterprise can extend into Cloud DC without having to set up IPsec paths between their on-prem CPEs and the Cloud GWs. This document describes a method for a Cloud DCs' gateway (GW) to connect multiple SD-WAN segments between the Cloud GW and the enterprise's CPEs without the Cloud GW decrypting and encrypting the payloads. By integration with Cloud Operators' gateways, enterprises can have advanced visibility through the Cloud Providers' global network topology, attachment level performance metrics, and telemetry data. 2. Conventions used in this document 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 BCP14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. The following acronyms and terms are used in this document: Dunbar, et al. Expires Dec 31, 2023 [Page 3] Internet-Draft Multi-segment SD-WAN rd Cloud DC: Off-Premises Data Center, managed by 3 party, that hosts applications, services, and workload for different organizations or tenants. CPE: Customer (Edge) Premises Equipment. OnPrem: On Premises data centers and branch offices. RR Route Reflector. SD-WAN: Software Defined Wide Area Network. In this document, "SD-WAN" refers to a policy-driven transporting of IP packets over multiple underlay networks for better WAN bandwidth management, visibility, and control. VPN Virtual Private Network. 3. Use Cases 3.1. Multi-segment SD-WAN via Single Cloud GW For enterprise branches that have established SD-WAN paths to a Cloud GW for accessing Cloud services, the Cloud GW can be utilized to connect those branches, as shown in Figure 1. Here are some reasons for connecting those branches via Cloud GW: - The public internet among those branches might have limited bandwidth, unpredictable connection, or be prone to cyber-attacks. In comparison, the network paths from CPEs to the Cloud GW have more reliable connections and are constantly monitored by sophisticated network functions. - It is easier to utilize Cloud based security functions, such as Firewall, DDoS, etc., to apply consistent policy enforcement for workloads/services to the Cloud and across the branches. - Cloud-based tools and SaaS can be easily utilized to collect and analyze the threat of traffic. Dunbar, et al. Expires Dec 31, 2023 [Page 4] Internet-Draft Multi-segment SD-WAN (^^^^^^^^^^^^) ( Cloud ) ( +----+ +----+ ) + -----(-|Edge| + GW | ) Direct | ( +----+ +/--\+ ) Connect | (^^^^^^^/^^^^\^) {-+---} / \ SD-WAN Path CPE<->GW { VPN } / \ {-+---} / IPsec Tunnel +-------+----/------+ \ | / | \ ++--/+ | +-\--+ |CPE1| +----+CPE2| +----+ +----+ Client Route: 11.1.1.x 10.1.1.x 21.1.1.x 20.1.1.x 30.1.1.x Figure 1 Multi-Segment SD-WAN stitching via a Cloud GW 3.2. Multi-segment SD-WAN via Cloud Backbone For geographic faraway enterprise branches that have established SD- WAN paths to their corresponding Cloud GWs to access Cloud services in different geographic locations, the Cloud backbone can connect those branches, as shown in Figure 2. The reasons to utilize the Cloud Backbone to interconnect those branches are similar to interconnecting multiple branches via a single Cloud GW described in the previous section. Dunbar, et al. Expires Dec 31, 2023 [Page 5] Internet-Draft Multi-segment SD-WAN (^^^^^^^^^^^^^^^) ( Cloud ) ( +----+ +----+ ) +-----+ + ---(-|Edge|==| GW1|=================== GW2 | Direct | ( +----+ +/--\+ ) +--|--+ Connect | (^^^^^^^/^^^^\^) | {-+---} / \ | { VPN } / \ +-----+ {-+---} / IPsec Tunnel |CPE10| +-------+--/--------+ \ +-----+ | / | \ 10.2.1.x ++/--+ | +\---+ 20.2.1.x |CPE1| +----+CPE2| 30.2.1.x +----+ +----+ Client Route: 11.1.1.x 10.1.1.x 21.1.1.x 20.1.1.x 30.1.1.x Figure 2 Multi-Segment SD-WAN Stitching via Cloud Backbone 3.3. Why not use policy-based traffic steering There are many well-developed methods, such as SRv6 or MPLS-TE, to steer traffic through specific nodes. Those traffic steering methods are effective when the entire network domain is under one administrative control. However, the traffic from on-prem CPEs to Cloud GWs via the public internet can only be forwarded based on the packets' destination addresses. SD-WAN allows for the setup of multiple links (paths) from the same SD-WAN branch CPE to a Cloud GW; each link represents a dual tunnel connection from a unique public IP of the SD-WAN CPE to two different instances of Cloud GW. Using Cloud GW to interconnect those on-prem CPEs eliminates the need to manage the multiple ISPs' links/paths between the CPEs. Dunbar, et al. Expires Dec 31, 2023 [Page 6] Internet-Draft Multi-segment SD-WAN 4. Data Plane encoding for SD-WAN Transit As the GENEVE Encapsulation [RFC8926] is supported by most Cloud Service Providers, GENEVE is chosen as the encapsulation header to steer SD-WAN flows among CPEs through the specified Cloud GWs. 4.1. GENEVE header encoding Geneve header shown below is specified by RFC8926: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Ver| Opt Len |O|C| Rsvd. | Protocol Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Virtual Network Identifier (VNI) | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ Variable-Length Options ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ VNI (virtual network Identifier) is used to represent the Customer Identifier. The Protocol Type (16 bits) = 50 (ESP) [RFC4303] indicates that IPsec ESP encapsulated data are appended at the end of the GENEVE header. 4.2. Multi-Segment SD-WAN Option Class Need IANA to assign a new GENEVE Option Class dedicated for Multi- segment SD-WAN. Dunbar, et al. Expires Dec 31, 2023 [Page 7] Internet-Draft Multi-segment SD-WAN 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | multi-seg-SD-WAN Option Class | Type |R|R|R| Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ SD-WAN Tunnel Endpoint Sub-TLV ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ Optional SD-WAN Tunnel Originator Sub-TLV ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ Optional Egress GW Sub-TLV ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ // // // Optional Type Length Value objects (variable) // // // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type indicates the various types of multi-segment SD-WAN. Type = 1: Single Hop Transit SD-WAN Type = 2: Multi-Hop Transit SD-WAN with explicitly specified egress Cloud GW. Type = 3: Multi-Hop Transit SD-WAN without specified egress Cloud GW. 4.3. SD-WAN Endpoint Sub-TLV The SD-WAN Endpoint sub-TLV indicates the destination CPE of the IPsec Tunnel. As shown in Figure 1, for the SD-WAN IPsec SA from CPE1 to CPE2, the Tunnel Endpoint Sub-TLV of the Geneve Header has the CPE2's IP address. Dunbar, et al. Expires Dec 31, 2023 [Page 8] Internet-Draft Multi-segment SD-WAN 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |SD-WAN Endpoint| length | Reserved | TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SD-WAN Dst Addr Family | Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ (variable) + ~ ~ | SD-WAN end point Address +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ TTL is set by the SD-WAN Tunnel Originator, e.g., CPE1. Each transit node or transit region/zone (visible to the CPEs) can decrement the TTL so that the destination CPE can know the number of logical transit nodes (cloud regions or zones) the packet has traversed. Enterprises can also use TTL to set the maximum transit nodes/regions the packets traverse. 4.4. SD-WAN Tunnel Origin Endpoint Sub-TLV The SD-WAN Tunnel Origin Endpoint sub-TLV indicates the originating CPE of the IPsec Tunnel. As shown in Figure 1, for the SD-WAN IPsec SA from CPE1 to CPE2, the Tunnel Origin Endpoint Sub-TLV of the Geneve Header indicates CPE1's address. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |SDWAN OriginEnd| length | reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SD-WAN Org Addr Family | Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ (variable) + ~ ~ | SD-WAN Tunnel Origin Endpoint Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The Tunnel Origin Endpoint Sub-TLV in the GENEVE header can assist Cloud transit nodes in applying appropriate policies when forwarding the packet. However, including the Tunnel Origin Endpoint Sub-TLV in the GENEVE header is optional. Dunbar, et al. Expires Dec 31, 2023 [Page 9] Internet-Draft Multi-segment SD-WAN 4.5. Egress GW Sub-TLV For the multi-segment SD-WAN via Cloud Backbone scenario, the originator CPE can use the Egress GW Sub-TLV to specify the Egress Cloud GW for reaching the destination CPE. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |SDWAN EgressGW | length | reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Egress GW Addr Family | Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ (variable) + ~ ~ | Egress GW Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 4.6. Include-Transit Sub-TLV Include-Transit Sub-TLV is an optional Sub-TLV for explicitly including a list of Cloud Availability Regions or Zones for reasons like: - Those regions have certain OAM and security functions for the improved visibility. - To comply with regulations, etc. 4.7. Exclude-Transit Sub-TLV Exclude-Transit Sub-TLV is an optional Sub-TLV for explicitly excluding a list of Cloud Availability Regions or Zones for reasons like o To comply with regulations o To avoid regions that impose certain risks. 5. IPsec Flow through Cloud GWs Illustration This section illustrates Cloud GWs connecting traffic flow carried by the IPsec tunnels. Dunbar, et al. Expires Dec 31, 2023 [Page 10] Internet-Draft Multi-segment SD-WAN 5.1. Single Hop Cloud GW Assuming that all CPEs are under one administrative control (e.g., iBGP). Using Figure 1 as an example: - There is a bidirectional IPsec tunnel between CPE1 and Cloud GW; with IPsec SA1 for the traffic from the CPE1 to the Cloud-GW; and IPsec SA2 for the traffic from the Cloud-GW to the CPE1. - There is a bidirectional IPsec tunnel between CPE2 and Cloud GW; with IPsec SA3 for the traffic from the CPE2 to the Cloud-GW; and IPsec SA4 for the traffic from the Cloud-GW to the CPE2. - All the CPEs are under one iBGP administrative domain, with a Route Reflector (RR) as their controller. The CPEs notify their peers of their corresponding Cloud GW addresses (which is out of the scope of this document). When 11.1.1.x and 10.1.1.x need to communicate with each other, CPE1 and CPE2 establish a bidirectional IPsec Tunnel, with SA5 for the traffic from CPE1 to CPE2 and SA6 for the traffic from CPE2 to CPE1. Assume the IPsec ESP Tunnel Mode is used. A packet from 11.1.1.1 to 10.1.1.2 has the following outer header: Dunbar, et al. Expires Dec 31, 2023 [Page 11] Internet-Draft Multi-segment SD-WAN Outer IP header: +---------------------------+ | protocol = 17(UDP) | | src = CPE1 | | dst = Cloud GW | +---------------------------+ | Source Port =xxxx | | Dst Port = 6081 (GENEVE) | +===========================+ | GENEVE Header | | multi-seg-SD-WAN Option | |GENEVE Proto = 50 (ESP) | +- - -- -- - - -- - --+ |SD-WAN EndPt SubTLV (CPE2) | +---------------------------+ < ----------+ |SPI(Security Parameter Idx)| Authenticated +---------------------------+ | | sequence number | | +---------------------------+ <-+ | | payload IP header: | | | | src = 11.1.1.1 | | | | dst = 10.1.1.2 | | | +---------------------------+ Encrypted | | TCP header + | | | ~ payload (variable) ~ | | | | | | +===========================+ <-+ -------+ | Authentication Data | +---------------------------+ 5.2. Multi-hop Transit GWs Traffic to/from geographic apart CPEs can cross multiple Cloud DCs via Cloud backbone. The on-prem CPEs are under one administrative control (e.g., iBGP). Using Figure 2 as an example: - There is a bidirectional IPsec tunnel between CPE1 and the Cloud GW1; with IPsec SA1 for the traffic from the CPE1 to the Cloud-GW1; and IPsec SA2 for the traffic from the Cloud- GW1 to the CPE1. Dunbar, et al. Expires Dec 31, 2023 [Page 12] Internet-Draft Multi-segment SD-WAN - There is a bidirectional IPsec tunnel between CPE10 and the Cloud GW2; with IPsec SA3 for the traffic from the CPE10 to the Cloud-GW2; and IPsec SA4 for the traffic from the Cloud- GW2 to the CPE10. - All the CPEs are under one iBGP administrative domain, with a Route Reflector (RR) as their controller. CPEs notify their peers of their corresponding Cloud GW addresses. When 11.1.1.x and 10.2.1.x need to communicate with each other, CPE1 and CPE10 establish a bidirectional IPsec Tunnel, with SA5 for the traffic from CPE1 to CPE10 and SA6 for the traffic from CPE10 to CPE1. Assume the IPsec ESP Tunnel Mode is used, a packet from 11.1.1.1 to 10.2.1.2 has the following outer header: Outer IP header: +---------------------------+ | proto = 17 (UDP) | | src = CPE1 | | dst = Cloud GW1 | +===========================+ | GENEVE Header | | multi-seg-SD-WAN Option | |GENEVE Proto = 50 (ESP) | +- - -- -- - - -- - --+ |SD-WAN EndPt SubTLV (CPE10)| +---------------------------+ | EgressGW-SubTLV | +---------------------------+ < ----------+ |SPI(Security Parameter Idx)| Authenticated +---------------------------+ | | sequence number | | +---------------------------+ <-+ | | payload IP header: | | | | src = 11.1.1.1 | | | | dst = 10.2.1.2 | | | +---------------------------+ Encrypted | | TCP header + | | | ~ payload (variable) ~ | | | | | | +===========================+ <-+ -------+ | Authentication Data | +---------------------------+ Dunbar, et al. Expires Dec 31, 2023 [Page 13] Internet-Draft Multi-segment SD-WAN 5.3. Data Authentication and Integrity Check by Cloud GW The IPsec SA already encrypts the client payload between the CPEs, the Cloud GW doesn't need to decrypt and re-encrypt the payload when relaying it to the destination CPE. However, data authentication and integrity check are needed as the traffic traverse an untrusted network. RFC2403 and RFC2404 define authentication algorithms used in AH and ESP. MD5, SHA-1, SHA-256 are some of the cryptographic hashes, and they are part of a Hashed Message Authentication Code. 5.4. Packet Header Processing In Figure 1, upon receiving a GENEVE encapsulated packet with the GENEVE Protocol Type = 50 (ESP), the Cloud GW do the following: - Authenticate the packet using a preconfigured authentication method. - Extract the destination CPE address from the SD-WAN Endpoint Sub-TLV inside the GENEVE header. Replace the outer IP destination address with the destination CPE address. - Optionally replace the outer IP source address with the Cloud GW address. - GENEVE header is unchanged. - Forward the packet to the destination CPE. 6. Illustration of Traffic from Private VPN to IPsec Tunnel This section illustrates a Cloud GW connecting client traffic from a branch CPE via a Private VPN to another CPE via an IPsec tunnel. Using Figure 1 as an example: - CPE1 send traffic via a Private VPN (Direct Connect to the Cloud Edge) to the Cloud GW. The traffic is not encrypted. - There is a bidirectional IPsec tunnel between CPE2 and the Cloud GW; with IPsec SA1 for the traffic from the CPE2 to the Cloud-GW; and IPsec SA2 for the traffic from the Cloud-GW to the CPE2. - All the CPEs are under one iBGP administrative domain, with a Route Reflector (RR) as their controller. CPEs notify their peers of their corresponding Cloud GW addresses. Dunbar, et al. Expires Dec 31, 2023 [Page 14] Internet-Draft Multi-segment SD-WAN Assume the IPsec ESP Tunnel Mode is used for the IPsec SA between Cloud GW and CPE2. For a packet from 11.1.1.1 to 10.2.1.2, the following header is added by CPE1 sending over the Private VPN: Outer IP header: +---------------------------+ | proto = 17 (UDP) | | src = CPE1 | | dst = Cloud GW | +===========================+ | GENEVE Header | | multi-seg-SD-WAN Option | |GENEVE Proto =TCP/UDP/etc. | +- - -- -- - - -- - --+ |SD-WAN EndPt SubTLV (CPE2) | +---------------------------+ < -+ | payload IP header: | | | src = 11.1.1.1 | | | dst = 10.2.1.2 | | +---------------------------+ Not Encrypted | TCP header + | | ~ payload (variable) ~ | | | | +===========================+ <-+ Upon receiving the GENEVE encapsulated packet with the "Multi- Segment-SD-WAN" option, the Cloud GW extracts the destination CPE from the GENEVE header and encrypts the packet with the IPsec SA2 to forward to the destination (i.e., CPE2). The GENEVE Header is carried to the CPE2. Dunbar, et al. Expires Dec 31, 2023 [Page 15] Internet-Draft Multi-segment SD-WAN Outer IP header: +---------------------------+ | proto = 17 (UDP) | | src = Cloud GW | | dst = CPE2 | +===========================+ | GENEVE Header | | multi-seg-SD-WAN Option | |GENEVE Proto =50 (ESP) | +- - -- -- - - -- - --+ |SD-WAN EndPt SubTLV (CPE2) | +---------------------------+ < ----------+ |SPI(Security Parameter Idx)| Authenticated +---------------------------+ | | sequence number | | +---------------------------+ <-+ | | payload IP header: | | | | src = 11.1.1.1 | | | | dst = 10.2.1.2 | | | +---------------------------+ Encrypted | | TCP header + | | | ~ payload (variable) ~ | | | | | | +===========================+ <-+ -------+ | Authentication Data | +---------------------------+ 7. Control Plane consideration 7.1. Control Plane for CPEs The control plane enables SD-WAN edges to discover their properties and attached routes. The on-prem CPEs and their vCPEs (or Virtual Appliances in Cloud DC) can be controlled by one iBGP instance. [SDWAN-Edge-Discover] describes the mechanism for SD-WAN edges to discover each other's properties. The IPsec Key Exchange between on- prem CPEs and the vCPE is via the iBGP Update through RR. [SD-WAN- Edge-Discovery]. 7.2. Control Plane between CPEs and Cloud GWs It is common to have eBGP sessions between enterprises CPEs and the Cloud GWs. An enterprise-owned vCPE can establish an eBGP session with the Cloud VPN GW for accessing the workloads hosted in the Cloud DCs. If an IPsec tunnel is required between the Cloud DC GW Dunbar, et al. Expires Dec 31, 2023 [Page 16] Internet-Draft Multi-segment SD-WAN and the vCPE, the full suite of IPSec IKEv2 must be exchanged between the vCPE and the Cloud GW. 8. Observability Consideration This section is intended for describing some metrics that enterprises can get from Cloud providers for the traffic transited. To be added. 9. Manageability Considerations To be added. 10. Security Considerations To be added. 11. IANA Considerations Need IANA to assign a new GENEVE Option Class dedicated for Multi- segment SD-WAN. In addition, need the following IANA assignment: - SD-WAN Endpoint Sub-TLV Type - SD-WAN Origin Endpoint Sub-TLV Type - SDWAN Egress GW Sub-TLV Type 12. References 12.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. Dunbar, et al. Expires Dec 31, 2023 [Page 17] Internet-Draft Multi-segment SD-WAN [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, . [RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter, "Multiprotocol Extensions for BGP-4", RFC 4760, DOI 10.17487/RFC4760, January 2007, . [RFC7296] C. Kaufman, et al, "Internet Key Exchange Protocol Version 2 (IKEv2)", RFC7296, Oct. 2014. [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [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, . 12.2. Informative References [RFC8192] S. Hares, et al, "Interface to Network Security Functions (I2NSF) Problem Statement and Use Cases", July 2017 [RFC5521] P. Mohapatra, E. Rosen, "The BGP Encapsulation Subsequent Address Family Identifier (SAFI) and the BGP Tunnel Encapsulation Attribute", April 2009. [RFC9061] Marin-Lopez, R., Lopez-Millan, G., and F. Pereniguez- Garcia, "A YANG Data Model for IPsec Flow Protection Based on Software-Defined Networking (SDN)", RFC 9061, DOI 10.17487/RFC9061, July 2021, . [CONTROLLER-IKE] D. Carrel, et al, "IPsec Key Exchange using a Controller", draft-carrel-ipsecme-controller-ike-01, work- in-progress. Dunbar, et al. Expires Dec 31, 2023 [Page 18] Internet-Draft Multi-segment SD-WAN [LISP-GEOLOC] D. Farinacci, "LISP Geo-Coordinate Use-Case", draft- farinacci-lisp-geo-09, April 2020. [SDN-IPSEC] R. Lopez, G. Millan, "SDN-based IPsec Flow Protection", draft-ietf-i2nsf-sdn-ipsec-flow-protection-07, Aug 2019. [SECURE-EVPN] A. Sajassi, et al, "Secure EVPN", draft-sajassi-bess- secure-evpn-05, Oct 2021. [VPN-over-Internet] E. Rosen, "Provide Secure Layer L3VPNs over Public Infrastructure", draft-rosen-bess-secure-l3vpn-00, work-in-progress, July 2018 [DMVPN] Dynamic Multi-point VPN: https://www.cisco.com/c/en/us/products/security/dynamic- multipoint-vpn-dmvpn/index.html [DSVPN] Dynamic Smart VPN: http://forum.huawei.com/enterprise/en/thread-390771-1- 1.html [ITU-T-X1036] ITU-T Recommendation X.1036, "Framework for creation, storage, distribution and enforcement of policies for network security", Nov 2007. [Net2Cloud-Problem] L. Dunbar and A. Malis, "Dynamic Networks to Hybrid Cloud DCs Problem Statement", draft-ietf-rtgwg- net2cloud-problem-statement-22, March, 2023. [Net2Cloud-gap] L. Dunbar, A. Malis, and C. Jacquenet, "Networks Connecting to Hybrid Cloud DCs: Gap Analysis", draft-ietf- rtgwg-net2cloud-gap-analysis-07, July, 2020. [RFC9012] K. Patel, et al "The BGP Tunnel Encapsulation Attribute", RFC9012, April 2021. Dunbar, et al. Expires Dec 31, 2023 [Page 19] Internet-Draft Multi-segment SD-WAN 13. Acknowledgments Acknowledgements to XXX for their review and suggestions. This document was prepared using 2-Word-v2.0.template.dot. Dunbar, et al. Expires Dec 31, 2023 [Page 20] Internet-Draft Multi-segment SD-WAN Authors' Addresses Linda Dunbar Futurewei Email: ldunbar@futurewei.com Kausik Majumdar Microsoft Email: kmajumdar@microsoft.com Venkit Kasiviswanathan Arista Email: venkit@arista.com Ashok Ramchandra Microsoft Email: aramchandra@microsoft.com Contributors' Addresses Dunbar, et al. Expires Dec 31, 2023 [Page 21]