< draft-ietf-rtgwg-net2cloud-problem-statement-06.txt   draft-ietf-rtgwg-net2cloud-problem-statement-07.txt >
Network Working Group L. Dunbar Network Working Group L. Dunbar
Internet Draft Futurewei Internet Draft Futurewei
Intended status: Informational Andy Malis Intended status: Informational Andy Malis
Expires: August 5, 2020 Independent Expires: August 14, 2020 Independent
C. Jacquenet C. Jacquenet
Orange Orange
M. Toy M. Toy
Verizon Verizon
February 5, 2020 February 14, 2020
Dynamic Networks to Hybrid Cloud DCs Problem Statement Dynamic Networks to Hybrid Cloud DCs Problem Statement
draft-ietf-rtgwg-net2cloud-problem-statement-06 draft-ietf-rtgwg-net2cloud-problem-statement-07
Abstract Abstract
This document describes the problems that enterprises face today This document describes the problems that enterprises face today
when interconnecting their branch offices with dynamic workloads in when interconnecting their branch offices with dynamic workloads in
third party data centers (a.k.a. Cloud DCs). There can be many third party data centers (a.k.a. Cloud DCs). There can be many
problems associated with network connecting to or among Clouds, many problems associated with network connecting to or among Clouds, many
of which probably are out of the IETF scope. The objective of this of which probably are out of the IETF scope. The objective of this
document is to identify some of the problems that need additional document is to identify some of the problems that need additional
work in IETF Routing area. Other problems are out of the scope of work in IETF Routing area. Other problems are out of the scope of
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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 August 5, 2020. This Internet-Draft will expire on August 14, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the Copyright (c) 2020 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
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1. Introduction...................................................3 1. Introduction...................................................3
1.1. Key Characteristics of Cloud Services:....................3 1.1. Key Characteristics of Cloud Services:....................3
1.2. Connecting to Cloud Services..............................3 1.2. Connecting to Cloud Services..............................3
1.3. The role of SD-WAN in connecting to Cloud Services........4 1.3. The role of SD-WAN in connecting to Cloud Services........4
2. Definition of terms............................................5 2. Definition of terms............................................5
3. High Level Issues of Connecting to Multi-Cloud.................6 3. High Level Issues of Connecting to Multi-Cloud.................6
3.1. Security Issues...........................................6 3.1. Security Issues...........................................6
3.2. Authorization and Identity Management.....................6 3.2. Authorization and Identity Management.....................6
3.3. API abstraction...........................................7 3.3. API abstraction...........................................7
3.4. DNS for Cloud Resources...................................8 3.4. DNS for Cloud Resources...................................8
3.5. NAT for Cloud Services....................................8 3.5. NAT for Cloud Services....................................9
3.6. Cloud Discovery...........................................9 3.6. Cloud Discovery...........................................9
4. Interconnecting Enterprise Sites with Cloud DCs................9 4. Interconnecting Enterprise Sites with Cloud DCs...............10
4.1. Sites to Cloud DC........................................10 4.1. Sites to Cloud DC........................................10
4.2. Inter-Cloud Interconnection..............................12 4.2. Inter-Cloud Interconnection..............................12
5. Problems with MPLS-based VPNs extending to Hybrid Cloud DCs...13 5. Problems with MPLS-based VPNs extending to Hybrid Cloud DCs...14
6. Problem with using IPsec tunnels to Cloud DCs.................15 6. Problem with using IPsec tunnels to Cloud DCs.................15
6.1. Scaling Issues with IPsec Tunnels........................15 6.1. Scaling Issues with IPsec Tunnels........................15
6.2. Poor performance over long distance......................15 6.2. Poor performance over long distance......................16
7. Problems of Using SD-WAN to connect to Cloud DCs..............16 7. Problems of Using SD-WAN to connect to Cloud DCs..............16
7.1. More Complexity to Edge Nodes............................16 7.1. More Complexity to Edge Nodes............................17
7.2. Edge WAN Port Management.................................17 7.2. Edge WAN Port Management.................................17
7.3. Forwarding based on Application..........................17 7.3. Forwarding based on Application..........................18
8. End-to-End Security Concerns for Data Flows...................17 8. End-to-End Security Concerns for Data Flows...................18
9. Requirements for Dynamic Cloud Data Center VPNs...............17 9. Requirements for Dynamic Cloud Data Center VPNs...............18
10. Security Considerations......................................18 10. Security Considerations......................................19
11. IANA Considerations..........................................18 11. IANA Considerations..........................................19
12. References...................................................18 12. References...................................................19
12.1. Normative References....................................18 12.1. Normative References....................................19
12.2. Informative References..................................19 12.2. Informative References..................................19
13. Acknowledgments..............................................19 13. Acknowledgments..............................................20
1. Introduction 1. Introduction
1.1. Key Characteristics of Cloud Services: 1.1. Key Characteristics of Cloud Services:
Key characteristics of Cloud Services are on-demand, scalable, Key characteristics of Cloud Services are on-demand, scalable,
highly available, and usage-based billing. Cloud Services, such as, highly available, and usage-based billing. Cloud Services, such as,
compute, storage, network functions (most likely virtual), third compute, storage, network functions (most likely virtual), third
party managed applications, etc. are usually hosted and managed by third parties Cloud Operators. Here are some examples of Cloud network party managed applications, etc. are usually hosted and managed by rd 3 parties Cloud Operators. Here are some examples of Cloud network
functions: Virtual Firewall services, Virtual private network functions: Virtual Firewall services, Virtual private network
services, Virtual PBX services including voice and video services, Virtual PBX services including voice and video
conferencing systems, etc. Cloud Data Center (DC) is shared conferencing systems, etc. Cloud Data Center (DC) is shared
infrastructure that hosts the Cloud Services to many customers. infrastructure that hosts the Cloud Services to many customers.
1.2. Connecting to Cloud Services 1.2. Connecting to Cloud Services
With the advent of widely available third-party cloud DCs and With the advent of widely available third-party cloud DCs and
services in diverse geographic locations and the advancement of services in diverse geographic locations and the advancement of
tools for monitoring and predicting application behaviors, it is tools for monitoring and predicting application behaviors, it is
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For enterprises utilizing Cloud services by different cloud For enterprises utilizing Cloud services by different cloud
operators, it is necessary to establish policies and rules on operators, it is necessary to establish policies and rules on
how/where to forward DNS queries to. When applications in one Cloud how/where to forward DNS queries to. When applications in one Cloud
need to communication with applications hosted in another Cloud, need to communication with applications hosted in another Cloud,
there could be DNS queries from one Cloud DC being forwarded to the there could be DNS queries from one Cloud DC being forwarded to the
enterprise's on premise DNS, which in turn be forwarded to the DNS enterprise's on premise DNS, which in turn be forwarded to the DNS
service in another Cloud. Needless to say, configuration can be service in another Cloud. Needless to say, configuration can be
complex depending on the application communication patterns. complex depending on the application communication patterns.
However, even with carefully managed policies and configurations,
collisions can still occur. If you use an internal name like .cloud
and then want your services to be available via or within some other
cloud provider which also uses .cloud, then it can't work.
Therefore, it is better to use the global domain name even when an
organization does not make all its namespace globally resolvable. An
organization's globally unique DNS can include subdomains that
cannot be resolved at all outside certain restricted paths, zones
that resolve differently based on the origin of the query, and zones
that resolve the same globally for all queries from any source.
Globally unique names do not equate to globally resolvable names or
even global names that resolve the same way from every perspective.
Globally unique names do prevent any possibility of collision at the
present or in the future and they make DNSSEC trust manageable. It's
not as if there is or even could be some sort of shortage in
available names that can be used, especially when subdomains and the
ability to delegate administrative boundaries are considered.
3.5. NAT for Cloud Services 3.5. NAT for Cloud Services
Cloud resources, such as VM instances, are usually assigned with Cloud resources, such as VM instances, are usually assigned with
private IP addresses. By configuration, some private subnets can private IP addresses. By configuration, some private subnets can
have the NAT function to reach out to external network and some have the NAT function to reach out to external network and some
private subnets are internal to Cloud only. private subnets are internal to Cloud only.
Different Cloud operators support different levels of NAT functions. Different Cloud operators support different levels of NAT functions.
For example, AWS NAT Gateway does not currently support connections For example, AWS NAT Gateway does not currently support connections
towards, or from VPC Endpoints, VPN, AWS Direct Connect, or VPC towards, or from VPC Endpoints, VPN, AWS Direct Connect, or VPC
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globally routable CIDR from private IPv4 address ranges as specified globally routable CIDR from private IPv4 address ranges as specified
by RFC1918. To establish IPsec tunnel between two Cloud DCs, it is by RFC1918. To establish IPsec tunnel between two Cloud DCs, it is
necessary to exchange Public routable addresses for applications in necessary to exchange Public routable addresses for applications in
different Cloud DCs. [BGP-SDWAN] describes one method. Other methods different Cloud DCs. [BGP-SDWAN] describes one method. Other methods
are worth exploring. are worth exploring.
In summary, here are some approaches, available now (which might In summary, here are some approaches, available now (which might
change in the future), to interconnect workloads among different change in the future), to interconnect workloads among different
Cloud DCs: Cloud DCs:
a) Utilize Cloud DC provided inter/intra-cloud connectivity a) Utilize Cloud DC provided inter/intra-cloud connectivity
services (e.g., AWS Transit Gateway) to connect workloads services (e.g., AWS Transit Gateway) to connect workloads
instantiated in multiple VPCs. Such services are provided with instantiated in multiple VPCs. Such services are provided with
the cloud gateway to connect to external networks (e.g., AWS the cloud gateway to connect to external networks (e.g., AWS
DirectConnect Gateway). DirectConnect Gateway).
b) Hairpin all traffic through the customer gateway, meaning all b) Hairpin all traffic through the customer gateway, meaning all
workloads are directly connected to the customer gateway, so workloads are directly connected to the customer gateway, so
that communications among workloads within one Cloud DC must that communications among workloads within one Cloud DC must
traverse through the customer gateway. traverse through the customer gateway.
c) Establish direct tunnels among different VPCs (AWS' Virtual c) Establish direct tunnels among different VPCs (AWS' Virtual
Private Clouds) and VNET (Azure's Virtual Networks) via Private Clouds) and VNET (Azure's Virtual Networks) via
client's own virtual routers instantiated within Cloud DCs. client's own virtual routers instantiated within Cloud DCs.
DMVPN (Dynamic Multipoint Virtual Private Network) or DSVPN DMVPN (Dynamic Multipoint Virtual Private Network) or DSVPN
(Dynamic Smart VPN) techniques can be used to establish direct (Dynamic Smart VPN) techniques can be used to establish direct
Multi-point-to-Point or multi-point-to multi-point tunnels Multi-point-to-Point or multi-point-to multi-point tunnels
among those client's own virtual routers. 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.
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[RFC4664] L. Andersson and E. Rosen, "Framework for Layer 2 Virtual [RFC4664] L. Andersson and E. Rosen, "Framework for Layer 2 Virtual
Private Networks (L2VPNs)", Sept 2006. Private Networks (L2VPNs)", Sept 2006.
[BGP-SDWAN] L. Dunbar, et al. "BGP Extension for SDWAN Overlay [BGP-SDWAN] L. Dunbar, et al. "BGP Extension for SDWAN Overlay
Networks", draft-dunbar-idr-bgp-sdwan-overlay-ext-03, Networks", draft-dunbar-idr-bgp-sdwan-overlay-ext-03,
work-in-progress, Nov 2018. work-in-progress, Nov 2018.
13. Acknowledgments 13. Acknowledgments
Many thanks to Alia Atlas, Chris Bowers, Ignas Bagdonas, Michael Many thanks to Alia Atlas, Chris Bowers, Paul Vixie, Paul Ebersman,
Huang, Liu Yuan Jiao, Katherine Zhao, and Jim Guichard for the Timothy Morizot, Ignas Bagdonas, Michael Huang, Liu Yuan Jiao,
discussion and contributions. Katherine Zhao, and Jim Guichard for the discussion and
contributions.
Authors' Addresses Authors' Addresses
Linda Dunbar Linda Dunbar
Futurewei Futurewei
Email: Linda.Dunbar@futurewei.com Email: Linda.Dunbar@futurewei.com
Andrew G. Malis Andrew G. Malis
Independent Independent
Email: agmalis@gmail.com Email: agmalis@gmail.com
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