< draft-ietf-rtgwg-net2cloud-problem-statement-02.txt		draft-ietf-rtgwg-net2cloud-problem-statement-03.txt >
	Network Working Group L. Dunbar		Network Working Group L. Dunbar
	Internet Draft A. Malis		Internet Draft A. Malis
	Intended status: Informational Futurewei		Intended status: Informational Futurewei
	Expires: Dec 2019 C. Jacquenet		Expires: Dec 2019 C. Jacquenet
	Orange		Orange
	M. Toy		M. Toy
	Verizon		Verizon
	June 17, 2019		July 3, 2019
	Dynamic Networks to Hybrid Cloud DCs Problem Statement		Dynamic Networks to Hybrid Cloud DCs Problem Statement
	draft-ietf-rtgwg-net2cloud-problem-statement-02		draft-ietf-rtgwg-net2cloud-problem-statement-03
	Abstract		Abstract
	This document describes the problems that enterprises face today		This document describes the problems that enterprises face today
	when connecting their branch offices to dynamic workloads in third		when connecting their branch offices to dynamic workloads in third
	party data centers (a.k.a. Cloud DCs).		party data centers (a.k.a. Cloud DCs).
	It examines some of the approaches interconnecting cloud DCs with		It examines some of the approaches interconnecting cloud DCs with
	enterprises' on-premises DCs & branch offices. This document also		enterprises' on-premises DCs & branch offices. This document also
	describes some of the network problems that many enterprises face		describes some of the network problems that many enterprises face
	skipping to change at page 2, line 13 ¶		skipping to change at page 2, line 13 ¶
	months and may be updated, replaced, or obsoleted by other documents		months and may be updated, replaced, or obsoleted by other documents
	at any time. It is inappropriate to use Internet-Drafts as		at any time. It is inappropriate to use Internet-Drafts as
	reference material or to cite them other than as "work in progress."		reference material or to cite them other than as "work in progress."
	The list of current Internet-Drafts can be accessed at		The list of current Internet-Drafts can be accessed at
	http://www.ietf.org/ietf/1id-abstracts.txt		http://www.ietf.org/ietf/1id-abstracts.txt
	The list of Internet-Draft Shadow Directories can be accessed at		The list of Internet-Draft Shadow Directories can be accessed at
	http://www.ietf.org/shadow.html		http://www.ietf.org/shadow.html
	This Internet-Draft will expire on December 17, 2019.		This Internet-Draft will expire on January 3, 2009.
	Copyright Notice		Copyright Notice
	Copyright (c) 2019 IETF Trust and the persons identified as the		Copyright (c) 2019 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(http://trustee.ietf.org/license-info) in effect on the date of		(http://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 2, line 42 ¶		skipping to change at page 2, line 42 ¶
	1. Introduction...................................................3		1. Introduction...................................................3
	1.1. On the evolution of Cloud DC connectivity.................3		1.1. On the evolution of Cloud DC connectivity.................3
	1.2. The role of SD-WAN techniques in Cloud DC connectivity....4		1.2. The role of SD-WAN techniques in Cloud DC connectivity....4
	2. Definition of terms............................................4		2. Definition of terms............................................4
	3. Current Practices in Interconnecting Enterprise Sites with Cloud		3. Current Practices in Interconnecting Enterprise Sites with Cloud
	DCs...............................................................5		DCs...............................................................5
	3.1. Multiple connection to workloads in a Cloud DC............5		3.1. Multiple connection to workloads in a Cloud DC............5
	3.2. Interconnect to Hybrid Cloud DCs..........................7		3.2. Interconnect to Hybrid Cloud DCs..........................7
	3.3. Connecting workloads among hybrid Cloud DCs...............8		3.3. Connecting workloads among hybrid Cloud DCs...............8
	4. Desired Properties for Networks that interconnect Hybrid Clouds9		4. Desired Properties for Networks that interconnect Hybrid Clouds9
	5. Problems with MPLS-based VPNs extending to Hybrid Cloud DCs....9		5. Problems with MPLS-based VPNs extending to Hybrid Cloud DCs...10
	6. Problem with using IPsec tunnels to Cloud DCs.................11		6. Problem with using IPsec tunnels to Cloud DCs.................11
	6.1. Complexity of multi-point any-to-any interconnection.....11		6.1. Complexity of multi-point any-to-any interconnection.....12
	6.2. Poor performance over long distance......................12		6.2. Poor performance over long distance......................12
	6.3. Scaling Issues with IPsec Tunnels........................12		6.3. Scaling Issues with IPsec Tunnels........................13
	7. Problems of Using SD-WAN to connect to Cloud DCs..............13		7. Problems of Using SD-WAN to connect to Cloud DCs..............13
	7.1. SD-WAN among branch offices vs. interconnect to Cloud DCs13		7.1. SD-WAN among branch offices vs. interconnect to Cloud DCs14
	8. End-to-End Security Concerns for Data Flows...................16		8. End-to-End Security Concerns for Data Flows...................16
	9. Requirements for Dynamic Cloud Data Center VPNs...............16		9. Requirements for Dynamic Cloud Data Center VPNs...............16
	10. Security Considerations......................................17		10. Security Considerations......................................17
	11. IANA Considerations..........................................17		11. IANA Considerations..........................................17
	12. References...................................................17		12. References...................................................17
	12.1. Normative References....................................17		12.1. Normative References....................................17
	12.2. Informative References..................................17		12.2. Informative References..................................17
	13. Acknowledgments..............................................18		13. Acknowledgments..............................................18
	1. Introduction		1. Introduction
	skipping to change at page 5, line 23 ¶		skipping to change at page 5, line 23 ¶
	SD-WAN: Software Defined Wide Area Network. In this document,		SD-WAN: Software Defined Wide Area Network. In this document,
	"SD-WAN" refers to the solutions of pooling WAN		"SD-WAN" refers to the solutions of pooling WAN
	bandwidth from multiple underlay networks to get better		bandwidth from multiple underlay networks to get better
	WAN bandwidth management, visibility & control. When the		WAN bandwidth management, visibility & control. When the
	underlay networks are private networks, traffic can		underlay networks are private networks, traffic can
	traverse without additional encryption; when the		traverse without additional encryption; when the
	underlay networks are public, such as Internet, some		underlay networks are public, such as Internet, some
	traffic needs to be encrypted when traversing through		traffic needs to be encrypted when traversing through
	(depending on user provided policies).		(depending on user provided policies).
	VPC: Virtual Private Cloud. A service offered by Cloud DC		VPC: Virtual Private Cloud is a virtual network dedicated to
	operators to allocate logically-isolated cloud		one client account. It is logically isolated from other
	resources, including compute, networking and storage.		virtual networks in a Cloud DC. Each client can launch
			his/her desired resources, such as compute, storage, or
			network functions into his/her VPC. Most Cloud
			operators' VPCs only support private addresses, some
			support IPv4 only, others support IPv4/IPv6 dual stack.
	3. Current Practices in Interconnecting Enterprise Sites with Cloud DCs		3. Current Practices in Interconnecting Enterprise Sites with Cloud DCs
	3.1. Multiple connection to workloads in a Cloud DC		3.1. Multiple connection to workloads in a Cloud DC
	Most Cloud operators offer some type of network gateway through		Most Cloud operators offer some type of network gateway through
	which an enterprise can reach their workloads hosted in the Cloud		which an enterprise can reach their workloads hosted in the Cloud
	DCs. For example, AWS (Amazon Web Services) offers the following		DCs. For example, AWS (Amazon Web Services) offers the following
	options to reach workloads in AWS Cloud DCs:		options to reach workloads in AWS Cloud DCs:
	- AWS Internet gateway allows communication between instances in		- AWS Internet gateway allows communication between instances in
	AWS VPC and the internet.		AWS VPC and the internet.
	- AWS Virtual gateway (vGW) where IPsec tunnels [RFC6071] are		- AWS Virtual gateway (vGW) where IPsec tunnels [RFC6071] are
	established between an enterprise's own gateway and AWS vGW, so		established between an enterprise's own gateway and AWS vGW, so
	that the communications between those gateways can be secured		that the communications between those gateways can be secured
	from the underlay (which might be the public Internet).		from the underlay (which might be the public Internet).
	- AWS Direct Connect, which allows enterprises to purchase direct		- AWS Direct Connect, which allows enterprises to purchase direct
	connect from network service providers to get a private leased		connect from network service providers to get a private leased
	line interconnecting the enterprises gateway(s) and the AWS		line interconnecting the enterprises gateway(s) and the AWS
	Direct Connect routers. In addition, an AWS Transit Gateway can		Direct Connect routers. In addition, an AWS Transit Gateway
	be used to interconnect multiple VPCs in different Availability		(https://aws.amazon.com/transit -gateway/) can be used to interconnect
	Zones.		multiple VPCs in different Availability Zones. AWS Transit
			Gateway acts as a hub that controls how traffic is forwarded
			among all the connected networks which act like spokes.
	As an example, some branch offices of an enterprise can connect to		As an example, some branch offices of an enterprise can connect to
	over the Internet to reach AWS's vGW via IPsec tunnels. Other branch		over the Internet to reach AWS's vGW via IPsec tunnels. Other branch
	offices of the same enterprise can connect to AWS DirectConnect via		offices of the same enterprise can connect to AWS DirectConnect via
	a private network (without any encryption). ). It is important for		a private network (without any encryption). ). It is important for
	enterprises to be able to observe the specific behaviors when		enterprises to be able to observe the specific behaviors when
	connected by different connections.		connected by different connections.
	Figure below shows an example of some tenants' workloads are		Figure below shows an example of some tenants' workloads are
	accessible via a virtual router connected by AWS Internet Gateway;		accessible via a virtual router connected by AWS Internet Gateway;
	some are accessible via AWS vGW, and others are accessible via AWS		some are accessible via AWS vGW, and others are accessible via AWS
	Direct Connect. The vR1 can have its own IPsec capability for secure		Direct Connect. vR1 uses IPsec to establish secure tunnels over the
	tunnel over the internet to bypass paying additional price for the		Internet to avoid paying extra fees for the IPsec features provided
	IPsec features provided by AWS vGW. Some tenants can deploy separate		by AWS vGW. Some tenants can deploy separate virtual routers to
	virtual routers to connect to internet traffic and to traffic from		connect to internet traffic and to traffic from the secure channels
	the secure channels from vGW and DirectConnect, e.g. vR1 & vR2.		from vGW and DirectConnect, e.g. vR1 & vR2. Others may have one
	Others may have one virtual router connecting to both types of		virtual router connecting to both types of traffic. Customer Gateway
	traffic. Customer Gateway can be customer owned router or ports		can be customer owned router or ports physically connected to AWS
	physically connected to AWS Direct Connect GW.		Direct Connect GW.
	+------------------------+		+------------------------+
	| ,---. ,---. |		| ,---. ,---. |
	| (TN-1 ) ( TN-2)|		| (TN-1 ) ( TN-2)|
	| `-+-' +---+ `-+-' |		| `-+-' +---+ `-+-' |
	| +----|vR1|----+ |		| +----|vR1|----+ |
	| ++--+ |		| ++--+ |
	| | +-+----+		| | +-+----+
	| | /Internet\ For External		| | /Internet\ For External
	| +-------+ Gateway +----------------------		| +-------+ Gateway +----------------------
	skipping to change at page 7, line 40 ¶		skipping to change at page 7, line 40 ¶
	| +-------+ Gateway +----------+ gateway |		| +-------+ Gateway +----------+ gateway |
	| \ / Connect \ /		| \ / Connect \ /
	| +-+----+ +------+		| +-+----+ +------+
	| |		| |
	+------------------------+		+------------------------+
	Figure 1: Examples of Multiple Cloud DC connections.		Figure 1: Examples of Multiple Cloud DC connections.
	3.2. Interconnect to Hybrid Cloud DCs		3.2. Interconnect to Hybrid Cloud DCs
	Hybrid will be the most common usage of the cloud as more		It is likely that hybrid designs will become the rule for cloud
	enterprises see the benefits of integrating public and private cloud		services, as more enterprises see the benefits of integrating public
	infrastructures. However, enabling the growth of hybrid cloud		and private cloud infrastructures. However, enabling the growth of
	deployments in the enterprise requires fast and safe interconnection		hybrid cloud deployments in the enterprise requires fast and safe
	between public and private cloud services.		interconnection between public and private cloud services.
	For an enterprise to connect to applications & workloads hosted in		For an enterprise to connect to applications & workloads hosted in
	multiple Cloud DCs, the enterprise can use IPsec tunnels established		multiple Cloud DCs, the enterprise can use IPsec tunnels established
	over the Internet or a (virtualized) leased line service to connect		over the Internet or a (virtualized) leased line service to connect
	its on-premises gateways to each of the Cloud DC's gateways, virtual		its on-premises gateways to each of the Cloud DC's gateways, virtual
	routers instantiated in the Cloud DCs, or any other suitable design		routers instantiated in the Cloud DCs, or any other suitable design
	(including a combination thereof).		(including a combination thereof).
	Some enterprises prefer to instantiate their own virtual		Some enterprises prefer to instantiate their own virtual
	CPEs/routers inside the Cloud DC to connect the workloads within the		CPEs/routers inside the Cloud DC to connect the workloads within the
	Cloud DC. Then an overlay path is established between customer		Cloud DC. Then an overlay path is established between customer
	gateways to the virtual CPEs/routers for reaching the workloads		gateways to the virtual CPEs/routers for reaching the workloads
	inside the cloud DC.		inside the cloud DC.
	3.3. Connecting workloads among hybrid Cloud DCs		3.3. Connecting workloads among hybrid Cloud DCs
	There are multiple approaches to interconnect workloads among		There are multiple approaches to interconnect workloads among
	different Cloud DCs:		different Cloud DCs:
	a) Utilize Cloud DC provided transit gateways.		a) Utilize Cloud DC provided inter/intra-cloud connectivity
	b) Hairpin all the traffic through the customer gateway, or		services (e.g., AWS Transit Gateway) to connect workloads
			instantiated in multiple VPCs. Such services are provided with
			the cloud gateway to connect to external networks (e.g., AWS
			DirectConnect Gateway).
			b) Hairpin all traffic through the customer gateway, meaning all
			workloads are directly connected to the customer gateway, so
			that communications among workloads within one Cloud DC have to
			traverse through the customer gateway.
	c) Establish direct tunnels among different VPCs (Virtual Private		c) Establish direct tunnels among different VPCs (Virtual Private
	Clouds) via client's own virtual routers instantiated within		Clouds) via client's own virtual routers instantiated within
	Cloud DCs. DMVPN (Dynamic Multipoint Virtual Private Network)		Cloud DCs. DMVPN (Dynamic Multipoint Virtual Private Network)
	or DSVPN (Dynamic Smart VPN) techniques can be used to		or DSVPN (Dynamic Smart VPN) techniques can be used to
	establish direct Multi-point-to-Point or multi-point-to multi-		establish direct Multi-point-to-Point or multi-point-to multi-
	point tunnels among those client's own virtual routers.		point tunnels among those client's own virtual routers.
	Approach a) usually does not work if Cloud DCs are owned and managed		Approach a) usually does not work if Cloud DCs are owned and managed
	by different Cloud providers.		by different Cloud providers.
	skipping to change at page 10, line 41 ¶		skipping to change at page 11, line 8 ¶
	One of the main drivers for moving workloads into the cloud is		One of the main drivers for moving workloads into the cloud is
	the widely available cloud DCs at geographically diverse		the widely available cloud DCs at geographically diverse
	locations, where apps can be instantiated so that they can be		locations, where apps can be instantiated so that they can be
	as close to their end-users as possible. When the user base		as close to their end-users as possible. When the user base
	changes, the applications may be migrated to a new cloud DC		changes, the applications may be migrated to a new cloud DC
	location closest to the new user base.		location closest to the new user base.
	- Most of the cloud DCs do not expose their internal networks, so		- Most of the cloud DCs do not expose their internal networks, so
	the MPLS-based VPNs can only reach Cloud DC's Gateways, not to		the MPLS-based VPNs can only reach Cloud DC's Gateways, not to
	the workloads hosted inside. Even with AWS DirectConnect, the		the workloads hosted inside. Even with AWS DirectConnect, the
	connection only reaches the AWS DirectConnect Gateway.		connection only reaches the AWS DirectConnect Gateway. AWS
			DirectConnect Gateway uses BGP to exchange all routes with
			devices located behind the gateway, even including routes of
			applications that might be physically located in different
			geographical locations. There is no visibility on how the
			applications/workloads are interconnected within a Cloud DC or
			across multiple Cloud DCs.
	- Extensive usage of Overlay by Cloud DCs:		- Extensive usage of Overlay by Cloud DCs:
	Many cloud DCs use an overlay to connect their gateways to the		Many cloud DCs use an overlay to connect their gateways to the
	workloads located inside the DC. There is currently no standard		workloads located inside the DC. There is currently no standard
	that specifies the interworking between the Cloud Overlay and the		that specifies the interworking between the Cloud Overlay and
	enterprise' existing underlay networks. One of the		the enterprise' existing underlay networks. One of the
	characteristics of overlay networks is that some of the WAN ports rd of the edge nodes connect to 3 party networks. There is		characteristics of overlay networks is that some of the WAN
	therefore a need to propagate WAN port information to remote rd authorized peers in 3 party network domains in addition to route		ports of the edge nodes connect to third party networks. There
	propagation. Such an exchange cannot happen before communication		is therefore a need to propagate WAN port information to remote
	between peers is properly secured.		authorized peers in third party network domains in addition to
			route propagation. Such an exchange cannot happen before
			communication between peers is properly secured.
	Another roadblock is the lack of a standard way to express and		Another roadblock is the lack of a standard way to express and
	enforce consistent security policies for workloads that not only use		enforce consistent security policies for workloads that not only use
	virtual addresses, but in which are also very likely hosted in		virtual addresses, but in which are also very likely hosted in
	different locations within the Cloud DC [RFC8192]. The current VPN		different locations within the Cloud DC [RFC8192]. The current VPN
	path computation and bandwidth allocation schemes may not be		path computation and bandwidth allocation schemes may not be
	flexible enough to address the need for enterprises to rapidly		flexible enough to address the need for enterprises to rapidly
	connect to dynamically instantiated (or removed) workloads and		connect to dynamically instantiated (or removed) workloads and
	applications regardless of their location/nature (i.e., third party		applications regardless of their location/nature (i.e., third party
	cloud DCs).		cloud DCs).
	skipping to change at page 15, line 27 ¶		skipping to change at page 15, line 27 ¶
	| | +-+----+		| | +-+----+
	| | /Internet\ One path via		| | /Internet\ One path via
	| +-------+ Gateway +---------------------+		| +-------+ Gateway +---------------------+
	| \ / Internet \		| \ / Internet \
	| +-+----+ \		| +-+----+ \
	+------------------------+ \		+------------------------+ \
	\		\
	+------------------------+ native traffic \		+------------------------+ native traffic \
	| ,---. ,---. | without encryption|		| ,---. ,---. | without encryption|
	| (TN-3 ) ( TN-4)| |		| (TN-3 ) ( TN-4)| |
	| `-+-' +--+ `-+-' | | +------+		| `-+-' +--+ `-+-' | | +------+
	| +----|vR|-----+ | +--+ CPE |		| +----|vR|-----+ | +----+ CPE |
	| ++-+ | | +------+		| ++-+ | | +------+
	| | +-+----+ |		| | +-+----+ |
	| | / virtual\ One path via IPsec Tunnel |		| | / virtual\ One path via IPsec Tunnel |
	| +-------+ Gateway +-------------------------- +		| +-------+ Gateway +-------------------------- +
	| \ / Encrypted traffic over|		| \ / Encrypted traffic over|
	| +-+----+ public network |		| +-+----+ public network |
	+------------------------+ |		+------------------------+ |
	|		|
	+------------------------+ |		+------------------------+ |
	| ,---. ,---. | Native traffic |		| ,---. ,---. | Native traffic |
	| (TN-5 ) ( TN-6)| without encryption |		| (TN-5 ) ( TN-6)| without encryption |
	| `-+-' +--+ `-+-' | over secure network|		| `-+-' +--+ `-+-' | over secure network|
	| +----|vR|-----+ | |		| +----|vR|-----+ | |
	| ++-+ | |		| ++-+ | |
	| | +-+----+ +------+ |		| | +-+----+ +------+ |
	| | / \ Via Direct /customer\ |		| | / \ Via Direct /customer\ |
	| +-------+ Gateway +----------+ gateway |-----+		| +-------+ Gateway +----------+ gateway |-----+
	| \ / Connect \ /		| \ / Connect \ /
	| +-+----+ +------+		| +-+----+ +------+
	+------------------------+ Customer GW has physical connection to AWS GW.		+------------------------+Customer GW has physical connection to AWS GW
	Figure 2: Different Underlays to Reach Cloud DC		Figure 2: Different Underlays to Reach Cloud DC
	8. End-to-End Security Concerns for Data Flows		8. End-to-End Security Concerns for Data Flows
	When IPsec tunnels established from enterprise on-premises CPEs		When IPsec tunnels established from enterprise on-premises CPEs
	are terminated at the Cloud DC gateway where the workloads or		are terminated at the Cloud DC gateway where the workloads or
	applications are hosted, some enterprises have concerns regarding		applications are hosted, some enterprises have concerns regarding
	traffic to/from their workload being exposed to others behind the		traffic to/from their workload being exposed to others behind the
	data center gateway (e.g., exposed to other organizations that		data center gateway (e.g., exposed to other organizations that
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