draft-ietf-nvo3-use-case-17.txt   rfc8151.txt 
Network Working Group L. Yong
Internet Draft L. Dunbar
Category: Informational Huawei
M. Toy
Verizon
A. Isaac
Juniper Networks
V. Manral
Ionos Networks
Expires: July 2017 February 20, 2017
Use Cases for Data Center Network Virtualization Overlay Networks Internet Engineering Task Force (IETF) L. Yong
Request for Comments: 8151 L. Dunbar
Category: Informational Huawei
ISSN: 2070-1721 M. Toy
Verizon
A. Isaac
Juniper Networks
V. Manral
Nano Sec Co
May 2017
draft-ietf-nvo3-use-case-17 Use Cases for Data Center Network Virtualization Overlay Networks
Abstract Abstract
This document describes data center network virtualization overlay This document describes Network Virtualization over Layer 3 (NVO3)
(NVO3) network use cases that can be deployed in various data use cases that can be deployed in various data centers and serve
centers and serve different data center applications. different data-center applications.
Status of this Memo
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other groups may also distribute working documents as Internet-
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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 This document is not an Internet Standards Track specification; it is
http://www.ietf.org/ietf/1id-abstracts.txt. published for informational purposes.
The list of Internet-Draft Shadow Directories can be accessed at This document is a product of the Internet Engineering Task Force
http://www.ietf.org/shadow.html. (IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 7841.
This Internet-Draft will expire on July 21, 2017. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc8151.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction...................................................3 1. Introduction ....................................................3
1.1. Terminology...............................................4 1.1. Terminology ................................................4
1.2. NVO3 Background...........................................5 1.2. NVO3 Background ............................................5
2. DC with Large Number of Virtual Networks.......................6 2. DC with a Large Number of Virtual Networks ......................6
3. DC NVO3 virtual network and External Network Interconnection...6 3. DC NVO3 Virtual Network and External Network Interconnection ....6
3.1. DC NVO3 virtual network Access via the Internet...........7 3.1. DC NVO3 Virtual Network Access via the Internet ............7
3.2. DC NVO3 virtual network and SP WAN VPN Interconnection....8 3.2. DC NVO3 Virtual Network and SP WAN VPN Interconnection .....8
4. DC Applications Using NVO3.....................................9 4. DC Applications Using NVO3 ......................................9
4.1. Supporting Multiple Technologies..........................9 4.1. Supporting Multiple Technologies ...........................9
4.2. DC Applications Spanning Multiple Physical Zones.........10 4.2. DC Applications Spanning Multiple Physical Zones ..........10
4.3. Virtual Data Center (vDC)................................10 4.3. Virtual Data Center (vDC) .................................10
5. Summary.......................................................12 5. Summary ........................................................12
6. Security Considerations.......................................12 6. Security Considerations ........................................12
7. IANA Considerations...........................................13 7. IANA Considerations ............................................12
8. Informative References........................................13 8. Informative References .........................................13
Contributors.....................................................14 Acknowledgements...................................................14
Acknowledgements.................................................14 Contributors ......................................................15
Authors' Addresses...............................................15 Authors' Addresses.................................................16
1. Introduction 1. Introduction
Server virtualization has changed the Information Technology (IT) Server virtualization has changed the Information Technology (IT)
industry in terms of the efficiency, cost, and speed of providing industry in terms of the efficiency, cost, and speed of providing new
new applications and/or services such as cloud applications. However applications and/or services such as cloud applications. However,
traditional data center (DC) networks have limits in supporting traditional data center (DC) networks have limits in supporting cloud
cloud applications and multi tenant networks [RFC7364]. The goals of applications and multi-tenant networks [RFC7364]. The goal of data
data center network virtualization overlay (NVO3) networks are to center Network Virtualization over Layer 3 (NVO3) networks is to
decouple the communication among tenant systems from DC physical decouple the communication among tenant systems from DC physical
infrastructure networks and to allow one physical network infrastructure networks and to allow one physical network
infrastructure to: infrastructure to:
o Carry many NVO3 virtual networks and isolate the traffic of o carry many NVO3 virtual networks and isolate the traffic of
different NVO3 virtual networks on a physical network. different NVO3 virtual networks on a physical network.
o Provide independent address space in individual NVO3 virtual o provide independent address space in individual NVO3 virtual
network such as MAC and IP. network such as Media Access Control (MAC) and IP.
o Support flexible Virtual Machines (VM) and/or workload placement o Support flexible Virtual Machines (VMs) and/or workload placement
including the ability to move them from one server to another including the ability to move them from one server to another
without requiring VM address changes and physical infrastructure without requiring VM address changes and physical infrastructure
network configuration changes, and the ability to perform a "hot network configuration changes, and the ability to perform a "hot
move" with no disruption to the live application running on those move" with no disruption to the live application running on those
VMs. VMs.
These characteristics of NVO3 virtual networks help address the These characteristics of NVO3 virtual networks (VNs) help address the
issues that cloud applications face in data centers [RFC7364]. issues that cloud applications face in data centers [RFC7364].
Hosts in one NVO3 virtual network may communicate with hosts in Hosts in one NVO3 VN may communicate with hosts in another NVO3 VN
another NVO3 virtual network that is carried by the same physical that is carried by the same physical network, or different physical
network, or different physical network, via a gateway. The use case network, via a gateway. The use-case examples for the latter are as
examples for the latter are: 1) DCs that migrate toward an NVO3 follows:
solution will be done in steps, where a portion of tenant systems in
a VN are on virtualized servers while others exist on a LAN. 2) many
DC applications serve to Internet users who are on different
physical networks; 3) some applications are CPU bound, such as Big
Data analytics, and may not run on virtualized resources. The inter-
VN policies are usually enforced by the gateway.
This document describes general NVO3 virtual network use cases that 1) DCs that migrate toward an NVO3 solution will be done in steps,
apply to various data centers. The use cases described here where a portion of tenant systems in a VN are on virtualized
represent DC provider's interests and vision for their cloud servers while others exist on a LAN.
services. The document groups the use cases into three categories
from simple to sophiscated in terms of implementation. However the 2) many DC applications serve Internet users who are on different
physical networks;
3) some applications are CPU bound, such as Big Data analytics, and
may not run on virtualized resources.
The inter-VN policies are usually enforced by the gateway.
This document describes general NVO3 VN use cases that apply to
various data centers. The use cases described here represent the DC
provider's interests and vision for their cloud services. The
document groups the use cases into three categories from simple to
sophisticated in terms of implementation. However, the
implementation details of these use cases are outside the scope of implementation details of these use cases are outside the scope of
this document. These three categories are highlighted below: this document. These three categories are described below:
o Basic NVO3 virtual networks (Section 2). All Tenant Systems (TS) o Basic NVO3 VNs (Section 2). All Tenant Systems (TSs) in the
in the network are located within the same DC. The individual network are located within the same DC. The individual networks
networks can be either Layer 2 (L2) or Layer 3 (L3). The number can be either Layer 2 (L2) or Layer 3 (L3). The number of NVO3
of NVO3 virtual networks in a DC is much larger than the number VNs in a DC is much larger than the number that traditional VLAN-
that traditional VLAN based virtual networks [IEEE 802.1Q] can based virtual networks [IEEE802.1Q] can support.
support.
o A virtual network that spans across multiple Data Centers and/or o A virtual network that spans across multiple DCs and/or to
to customer premises where NVO3 virtual networks are constructed customer premises where NVO3 virtual networks are constructed and
and interconnect other virtual or physical networks outside the interconnect other virtual or physical networks outside the DC.
data center. An enterprise customer may use a traditional An enterprise customer may use a traditional carrier-grade VPN or
carrier-grade VPN or an IPsec tunnel over the Internet to an IPsec tunnel over the Internet to communicate with its systems
communicate with its systems in the DC. This is described in in the DC. This is described in Section 3.
Section 3.
o DC applications or services require an advanced network that o DC applications or services require an advanced network that
contains several NVO3 virtual networks that are interconnected by contains several NVO3 virtual networks that are interconnected by
gateways. Three scenarios are described in Section 4. (1) gateways. Three scenarios are described in Section 4:
supporting multiple technologies; (2) constructing several (1) supporting multiple technologies;
virtual networks as a tenant network; (3) applying NVO3 to a (2) constructing several virtual networks as a tenant network; and
virtual Data Center (vDC). (3) applying NVO3 to a virtual Data Center (vDC).
The document uses the architecture reference model defined in The document uses the architecture reference model defined in
[RFC7365] to describe the use cases. [RFC7365] to describe the use cases.
1.1. Terminology 1.1. Terminology
This document uses the terminology defined in [RFC7365] and This document uses the terminology defined in [RFC7365] and
[RFC4364]. Some additional terms used in the document are listed [RFC4364]. Some additional terms used in the document are listed
here. here.
ASBR: Autonomous System Border Routers (ASBR) ASBR: Autonomous System Border Router.
DMZ: Demilitarized Zone. A computer or small sub-network that sits DC: Data Center.
between a more trusted internal network, such as a corporate private
LAN, and an un-trusted or less trusted external network, such as the
public Internet.
DNS: Domain Name Service [RFC1035] DMZ: Demilitarized Zone. A computer or small subnetwork
between a more-trusted internal network, such as a
corporate private LAN, and an untrusted or less-trusted
external network, such as the public Internet.
DNS: Domain Name Service [RFC1035].
DC Operator: An entity that is responsible for constructing and DC Operator: An entity that is responsible for constructing and
managing all resources in data centers, including, but not limited managing all resources in DCs, including, but not
to, compute, storage, networking, etc. limited to, computing, storage, networking, etc.
DC Provider: An entity that uses its DC infrastructure to offer DC Provider: An entity that uses its DC infrastructure to offer
services to its customers. services to its customers.
NAT: Network Address Translation [RFC3022] NAT: Network Address Translation [RFC3022].
vGW: virtual Gateway; a gateway component used for an NVO3 virtual vGW: virtual GateWay. A gateway component used for an NVO3
network to interconnect with another virtual/physical network. virtual network to interconnect with another
virtual/physical network.
NVO3 virtual network: a virtual network that is implemented based NVO3: Network Virtualization over Layer 3. A virtual network
NVO3 architecture [NVO3-ARCH]. that is implemented based on the NVO3 architecture.
PE: Provider Edge PE: Provider Edge.
SP: Service Provider SP: Service Provider.
TS: A TS can be a physical server/device or a virtual machine (VM) TS: A Tenant System, which can be instantiated on a physical
on a server, i.e., end-device [RFC7365]. server or virtual machine (VM).
VRF-LITE: Virtual Routing and Forwarding - LITE [VRF-LITE] VRF-LITE: Virtual Routing and Forwarding - LITE [VRF-LITE].
VN: NVO3 virtual network. VN: Virtual Network
WAN VPN: Wide Area Network Virtual Private Network [RFC4364] VoIP: Voice over IP
[RFC7432]
1.2. NVO3 Background WAN VPN: Wide Area Network Virtual Private Network [RFC4364]
[RFC7432].
An NVO3 virtual network is a virtual network in a DC that is 1.2. NVO3 Background
implemented based on the NV03 architecture [RFC8014]. This
architecture is often referred to as an overlay architecture. The
traffic carried by an NVO3 virtual network is encapsulated at a
Network Virtual Edge (NVE) [RFC8014] and carried by a tunnel to
another NVE where the traffic is decapsulated and sent to a
destination Tenant System (TS). The NVO3 architecture decouples NVO3
virtual networks from the DC physical network configuration. The
architecture uses common tunnels to carry NVO3 traffic that belongs
to multiple NVO3 virtual networks.
An NVO3 virtual network may be an L2 or L3 domain. The network An NVO3 virtual network is in a DC that is implemented based on the
NVO3 architecture [RFC8014]. This architecture is often referred to
as an overlay architecture. The traffic carried by an NVO3 virtual
network is encapsulated at a Network Virtualization Edge (NVE)
[RFC8014] and carried by a tunnel to another NVE where the traffic is
decapsulated and sent to a destination Tenant System (TS). The NVO3
architecture decouples NVO3 virtual networks from the DC physical
network configuration. The architecture uses common tunnels to carry
NVO3 traffic that belongs to multiple NVO3 virtual networks.
An NVO3 virtual network may be an L2 or L3 domain. The network
provides switching (L2) or routing (L3) capability to support host provides switching (L2) or routing (L3) capability to support host
(i.e., tenant systems) communications. An NVO3 virtual network may (i.e., TS) communications. An NVO3 virtual network may be required
be required to carry unicast traffic and/or multicast, to carry unicast traffic and/or multicast or broadcast/unknown-
broadcast/unknown-unicast (for L2 only) traffic from/to tenant unicast (for L2 only) traffic to/from TSs. There are several ways to
systems. There are several ways to transport NVO3 virtual network transport NVO3 virtual network Broadcast, Unknown Unicast, and
BUM (Broadcast, Unknown-unicast, Multicast) traffic [NVO3MCAST]. Multicast (BUM) traffic [NVO3MCAST].
An NVO3 virtual network provides communications among Tenant Systems An NVO3 virtual network provides communications among TSs in a DC. A
(TS) in a DC. A TS can be a physical server/device or a virtual TS can be a physical server/device or a VM on a server end-device
machine (VM) on a server end-device [RFC7365]. [RFC7365].
2. DC with Large Number of Virtual Networks 2. DC with a Large Number of Virtual Networks
A DC provider often uses NVO3 virtual networks for internal A DC provider often uses NVO3 virtual networks for internal
applications where each application runs on many VMs or physical applications where each application runs on many VMs or physical
servers and the provider requires applications to be segregated from servers and the provider requires applications to be segregated from
each other. A DC may run a larger number of NVO3 virtual networks to each other. A DC may run a larger number of NVO3 virtual networks to
support many applications concurrently, where traditional IEEE802.1Q support many applications concurrently, where a traditional VLAN
based VLAN solution is limited to 4094 VLANs. solution based on IEEE 802.1Q is limited to 4094 VLANs.
Applications running on VMs may require different quantity of Applications running on VMs may require a different quantity of
computing resource, which may result in computing resource shortage computing resources, which may result in a computing-resource
on some servers and other servers being nearly idle. Shortage of shortage on some servers and other servers being nearly idle. A
computing resource may impact application performance. DC operators shortage of computing resources may impact application performance.
desire VM or workload movement for resource usage optimization. VM DC operators desire VM or workload movement for resource-usage
dynamic placement and mobility results in frequent changes of the optimization. VM dynamic placement and mobility results in frequent
binding between a TS and an NVE. The TS reachability update changes of the binding between a TS and an NVE. The TS reachability
mechanisms should take significantly less time than the typical re- update mechanisms should take significantly less time than the
transmission Time-out window of a reliable transport protocol such typical retransmission Timeout window of a reliable transport
as TCP and SCTP, so that end points' transport connections won't be protocol such as TCP and Stream Control Transmission Protocol (SCTP),
impacted by a TS becoming bound to a different NVE. The capability so that endpoints' transport connections won't be impacted by a TS
of supporting many TSs in a virtual network and many virtual becoming bound to a different NVE. The capability of supporting many
networks in a DC is critical for an NVO3 solution. TSs in a virtual network and many virtual networks in a DC is
critical for an NVO3 solution.
When NVO3 virtual networks segregate VMs belonging to different When NVO3 virtual networks segregate VMs belonging to different
applications, DC operators can independently assign MAC and/or IP applications, DC operators can independently assign MAC and/or IP
address space to each virtual network. This addressing is more address space to each virtual network. This addressing is more
flexible than requiring all hosts in all NVO3 virtual networks to flexible than requiring all hosts in all NVO3 virtual networks to
share one address space. In contrast, typical use of IEEE 802.1Q share one address space. In contrast, typical use of IEEE 802.1Q
VLANs requires a single common MAC address space. VLANs requires a single common MAC address space.
3. DC NVO3 virtual network and External Network Interconnection 3. DC NVO3 Virtual Network and External Network Interconnection
Many customers (enterprises or individuals) who utilize a DC Many customers (enterprises or individuals) who utilize a DC
provider's compute and storage resources to run their applications provider's compute and storage resources to run their applications
need to access their systems hosted in a DC through Internet or need to access their systems hosted in a DC through Internet or
Service Providers' Wide Area Networks (WAN). A DC provider can Service Providers' Wide Area Networks (WAN). A DC provider can
construct a NVO3 virtual network that provides connectivity to all construct a NVO3 virtual network that provides connectivity to all
the resources designated for a customer and allows the customer to the resources designated for a customer, and it allows the customer
access the resources via a virtual gateway (vGW). WAN connectivity to access the resources via a virtual GateWay (vGW). WAN
to the virtual gateway can be provided by VPN technologies such as connectivity to the vGW can be provided by VPN technologies such as
IPsec VPNs [RFC4301] and BGP/MPLS IP VPNs [RFC 4364]. IPsec VPNs [RFC4301] and BGP/MPLS IP VPNs [RFC4364].
If a virtual network spans multiple DC sites, one design using NVO3 If a virtual network spans multiple DC sites, one design using NVO3
is to allow the network to seamlessly span the sites without DC is to allow the network to seamlessly span the sites without DC
gateway routers' termination. In this case, the tunnel between a gateway routers' termination. In this case, the tunnel between a
pair of NVEs can be carried within other intermediate tunnels over pair of NVEs can be carried within other intermediate tunnels over
the Internet or other WANs, or an intra-DC tunnel and inter DC the Internet or other WANs, or an intra-DC tunnel and inter-DC
tunnel(s) can be stitched together to form an end-to-end tunnel tunnel(s) can be stitched together to form an end-to-end tunnel
between the pair of NVEs that are in different DC sites. Both cases between the pair of NVEs that are in different DC sites. Both cases
will form one NVO3 virtual network across multiple DC sites. will form one NVO3 virtual network across multiple DC sites.
Two use cases are described in the following sections. Two use cases are described in the following sections.
3.1. DC NVO3 virtual network Access via the Internet 3.1. DC NVO3 Virtual Network Access via the Internet
A customer can connect to an NVO3 virtual network via the Internet A customer can connect to an NVO3 virtual network via the Internet in
in a secure way. Figure 1 illustrates an example of this case. The a secure way. Figure 1 illustrates an example of this case. The
NVO3 virtual network has an instance at NVE1 and NVE2 and the two NVO3 virtual network has an instance at NVE1 and NVE2, and the two
NVEs are connected via an IP tunnel in the Data Center. A set of NVEs are connected via an IP tunnel in the DC. A set of TSs are
tenant systems are attached to NVE1 on a server. NVE2 resides on a attached to NVE1 on a server. NVE2 resides on a DC Gateway device.
DC Gateway device. NVE2 terminates the tunnel and uses the VNID on NVE2 terminates the tunnel and uses the VN Identifier (VNID) on the
the packet to pass the packet to the corresponding vGW entity on the packet to pass the packet to the corresponding vGW entity on the DC
DC GW (the vGW is the default gateway for the virtual network). A GW (the vGW is the default gateway for the virtual network). A
customer can access their systems, i.e., TS1 or TSn, in the DC via customer can access their systems, i.e., TS1 or TSn, in the DC via
the Internet by using an IPsec tunnel [RFC4301]. The IPsec tunnel is the Internet by using an IPsec tunnel [RFC4301]. The IPsec tunnel is
configured between the vGW and the customer gateway at the customer configured between the vGW and the customer gateway at the customer
site. Either a static route or Interior Border Gateway Protocol site. Either a static route or Internal Border Gateway Protocol
(iBGP) may be used for prefix advertisement. The vGW provides IPsec (IBGP) may be used for prefix advertisement. The vGW provides IPsec
functionality such as authentication scheme and encryption; iBGP functionality such as authentication scheme and encryption; IBGP
protocol traffic is carried within the IPsec tunnel. Some vGW traffic is carried within the IPsec tunnel. Some vGW features are
features are listed below: listed below:
o The vGW maintains the TS/NVE mappings and advertises the TS o The vGW maintains the TS/NVE mappings and advertises the TS prefix
prefix to the customer via static route or iBGP. to the customer via static route or IBGP.
o Some vGW functions such as firewall and load balancer can be o Some vGW functions such as the firewall and load-balancer (LB) can
performed by locally attached network appliance devices. be performed by locally attached network appliance devices.
o If the NVO3 virtual network uses different address space than o If the NVO3 virtual network uses different address space than
external users, then the vGW needs to provide the NAT function. external users, then the vGW needs to provide the NAT function.
o More than one IPsec tunnel can be configured for redundancy. o More than one IPsec tunnel can be configured for redundancy.
o The vGW can be implemented on a server or VM. In this case, IP o The vGW can be implemented on a server or VM. In this case, IP
tunnels or IPsec tunnels can be used over the DC infrastructure. tunnels or IPsec tunnels can be used over the DC infrastructure.
o DC operators need to construct a vGW for each customer. o DC operators need to construct a vGW for each customer.
Server+---------------+ Server+---------------+
| TS1 TSn | | TS1 TSn |
| |...| | | |...| |
| +-+---+-+ | Customer Site | +-+---+-+ | Customer Site
| | NVE1 | | +-----+ | | NVE1 | | +-----+
| +---+---+ | | GW | | +---+---+ | | GW |
skipping to change at page 8, line 27 skipping to change at page 8, line 32
| | NVE2 | | .-.' * ) | | NVE2 | | .-.' * )
| +---+---+ | ( * Internet ) | +---+---+ | ( * Internet )
| +---+---+. | ( * / | +---+---+. | ( * /
| | vGW | * * * * * * * * '-' '-' | | vGW | * * * * * * * * '-' '-'
| +-------+ | | IPsec \../ \.--/' | +-------+ | | IPsec \../ \.--/'
| +--------+ | Tunnel | +--------+ | Tunnel
+----------------+ +----------------+
DC Provider Site DC Provider Site
Figure 1 - DC Virtual Network Access via the Internet Figure 1: DC Virtual Network Access via the Internet
3.2. DC NVO3 virtual network and SP WAN VPN Interconnection 3.2. DC NVO3 Virtual Network and SP WAN VPN Interconnection
In this case, an Enterprise customer wants to use a Service Provider In this case, an enterprise customer wants to use a Service Provider
(SP) WAN VPN [RFC4364] [RFC7432] to interconnect its sites with an (SP) WAN VPN [RFC4364] [RFC7432] to interconnect its sites with an
NVO3 virtual network in a DC site. The Service Provider constructs a NVO3 virtual network in a DC site. The SP constructs a VPN for the
VPN for the enterprise customer. Each enterprise site peers with an enterprise customer. Each enterprise site peers with an SP PE. The
SP PE. The DC Provider and VPN Service Provider can build an NVO3 DC provider and VPN SP can build an NVO3 virtual network and a WAN
virtual network and a WAN VPN independently, and then interconnect VPN independently, and then interconnect them via a local link or a
them via a local link, or a tunnel between the DC GW and WAN tunnel between the DC GW and WAN PE devices. The control plane
Provider Edge (PE) devices. The control plane interconnection interconnection options between the DC and WAN are described in
options between the DC and WAN are described in [RFC4364]. Using the [RFC4364]. Using the option "a" specified in [RFC4364] with VRF-LITE
option A specified in [RFC4364] with VRF-LITE [VRF-LITE], both [VRF-LITE], both ASBRs, i.e., DC GW and SP PE, maintain a
Autonomous System Border Routers (ASBR), i.e., DC GW and SP PE, routing/forwarding table (VRF). Using the option "b" specified in
maintain a routing/forwarding table (VRF). Using the option B [RFC4364], the DC ASBR and SP ASBR do not maintain the VRF table;
specified in [RFC4364], the DC ASBR and SP ASBR do not maintain the they only maintain the NVO3 virtual network and VPN identifier
VRF table; they only maintain the NVO3 virtual network and VPN mappings, i.e., label mapping, and swap the label on the packets in
identifier mappings, i.e., label mapping, and swap the label on the the forwarding process. Both option "a" and option "b" allow the se
packets in the forwarding process. Both option A and B allow the of NVO3 VNs and VPNs using their own identifiers, and two identifiers
NVO3 virtual network and VPN using their own identifiers and two are mapped at the DC GW. With the option "c" in [RFC4364], the VN
identifiers are mapped at DC GW. With the option C in [RFC4364], the and VPN use the same identifier and both ASBRs perform the tunnel
VN and VPN use the same identifier and both ASBRs perform the tunnel stitching, i.e., tunnel segment mapping. Each option has pros and
stitching, i.e., tunnel segment mapping. Each option has pros/cons cons [RFC4364] and has been deployed in SP networks depending on the
[RFC4364] and has been deployed in SP networks depending on the application requirements. BGP is used in these options for route
application requirements. BGP is used in these options for route distribution between DCs and SP WANs. Note that if the DC is the
distribution between DCs and SP WANs. Note that if the DC is the SP's DC, the DC GW and SP PE can be merged into one device that
SP's Data Center, the DC GW and SP PE in this case can be merged performs the interworking of the VN and VPN within an Autonomous
into one device that performs the interworking of the VN and VPN System.
within an AS.
These solutions allow the enterprise networks to communicate with These solutions allow the enterprise networks to communicate with the
the tenant systems attached to the NVO3 virtual network in the DC tenant systems attached to the NVO3 virtual network in the DC without
without interfering with the DC provider's underlying physical interfering with the DC provider's underlying physical networks and
networks and other NVO3 virtual networks in the DC. The enterprise other NVO3 virtual networks in the DC. The enterprise can use its
can use its own address space in the NVO3 virtual network. The DC own address space in the NVO3 virtual network. The DC provider can
provider can manage which VM and storage elements attach to the NVO3 manage which VM and storage elements attach to the NVO3 virtual
virtual network. The enterprise customer manages which applications network. The enterprise customer manages which applications run on
run on the VMs without knowing the location of the VMs in the DC. the VMs without knowing the location of the VMs in the DC. (See
(See Section 4 for more) Section 4 for more information.)
Furthermore, in this use case, the DC operator can move the VMs Furthermore, in this use case, the DC operator can move the VMs
assigned to the enterprise from one sever to another in the DC assigned to the enterprise from one sever to another in the DC
without the enterprise customer being aware, i.e., with no impact on without the enterprise customer being aware, i.e., with no impact on
the enterprise's 'live' applications. Such advanced technologies the enterprise's "live" applications. Such advanced technologies
bring DC providers great benefits in offering cloud services, but bring DC providers great benefits in offering cloud services, but add
add some requirements for NVO3 [RFC7364] as well. some requirements for NVO3 [RFC7364] as well.
4. DC Applications Using NVO3 4. DC Applications Using NVO3
NVO3 technology provides DC operators with the flexibility in NVO3 technology provides DC operators with the flexibility in
designing and deploying different applications in an end-to-end designing and deploying different applications in an end-to-end
virtualization overlay environment. The operators no longer need to virtualization overlay environment. The operators no longer need to
worry about the constraints of the DC physical network configuration worry about the constraints of the DC physical network configuration
when creating VMs and configuring a network to connect them. A DC when creating VMs and configuring a network to connect them. A DC
provider may use NVO3 in various ways, in conjunction with other provider may use NVO3 in various ways, in conjunction with other
physical networks and/or virtual networks in the DC. This section physical networks and/or virtual networks in the DC. This section
highlights some use cases for this goal. highlights some use cases for this goal.
4.1. Supporting Multiple Technologies 4.1. Supporting Multiple Technologies
Servers deployed in a large data center are often installed at Servers deployed in a large DC are often installed at different
different times, and may have different capabilities/features. Some times, and they may have different capabilities/features. Some
servers may be virtualized, while others may not; some may be servers may be virtualized, while others may not; some may be
equipped with virtual switches, while others may not. For the equipped with virtual switches, while others may not. For the
servers equipped with Hypervisor-based virtual switches, some may servers equipped with Hypervisor-based virtual switches, some may
support a standardized NVO3 encapsulation, some may not support any support a standardized NVO3 encapsulation, some may not support any
encapsulation, and some may support a documented encapsulation encapsulation, and some may support a documented encapsulation
protocol (e.g. VxLAN [RFC7348], NVGRE [RFC7637]) or proprietary protocol (e.g., Virtual eXtensible Local Area Network (VXLAN)
encapsulations. To construct a tenant network among these servers [RFC7348] and Network Virtualization using Generic Routing
and the ToR switches, operators can construct one traditional VLAN Encapsulation (NVGRE) [RFC7637]) or proprietary encapsulations. To
network and two virtual networks where one uses VxLAN encapsulation construct a tenant network among these servers and the Top-of-Rack
and the other uses NVGRE, and interconnect these three networks via (ToR) switches, operators can construct one traditional VLAN network
a gateway or virtual GW. The GW performs packet and two virtual networks where one uses VXLAN encapsulation and the
encapsulation/decapsulation translation between the networks. other uses NVGRE, and interconnect these three networks via a gateway
or virtual GW. The GW performs packet encapsulation/decapsulation
translation between the networks.
Another case is that some software of a tenant has high CPU and Another case is that some software of a tenant has high CPU and
memory consumption, which only makes a sense to run on standalone memory consumption, which only makes sense to run on standalone
servers; other software of the tenant may be good to run on VMs. servers; other software of the tenant may be good to run on VMs.
However provider DC infrastructure is configured to use NVO3 to However, provider DC infrastructure is configured to use NVO3 to
connect VMs and VLAN [IEEE802.1Q] to physical servers. The tenant connect VMs and VLANs [IEEE802.1Q] to physical servers. The tenant
network requires interworking between NVO3 and traditional VLAN. network requires interworking between NVO3 and traditional VLAN.
4.2. DC Applications Spanning Multiple Physical Zones 4.2. DC Applications Spanning Multiple Physical Zones
A DC can be partitioned into multiple physical zones, with each zone A DC can be partitioned into multiple physical zones, with each zone
having different access permissions and runs different applications. having different access permissions and running different
For example, a three-tier zone design has a front zone (Web tier) applications. For example, a three-tier zone design has a front zone
with Web applications, a mid zone (application tier) where service (Web tier) with Web applications, a mid zone (application tier) where
applications such as credit payment or ticket booking run, and a service applications such as credit payment or ticket booking run,
back zone (database tier) with Data. External users are only able to and a back zone (database tier) with Data. External users are only
communicate with the Web application in the front zone; the back able to communicate with the Web application in the front zone; the
zone can only receive traffic from the application zone. In this back zone can only receive traffic from the application zone. In
case, communications between the zones must pass through one or more this case, communications between the zones must pass through one or
security functions in a physical DMZ zone. Each zone can be more security functions in a physical DMZ zone. Each zone can be
implemented by one NVO3 virtual network and the security functions implemented by one NVO3 virtual network and the security functions in
in DMZ zone can be used to between two NVO3 virtual networks, i.e., DMZ zone can be used to between two NVO3 virtual networks, i.e., two
two zones. If network functions (NF), especially the security zones. If network functions (NFs), especially the security functions
functions in the physical DMZ can't process encapsulated NVO3 in the physical DMZ, can't process encapsulated NVO3 traffic, the
traffic, the NVO3 tunnels have to be terminated for the NF to NVO3 tunnels have to be terminated for the NF to perform its
perform its processing on the application traffic. processing on the application traffic.
4.3. Virtual Data Center (vDC) 4.3. Virtual Data Center (vDC)
An enterprise data center today may deploy routers, switches, and An enterprise DC may deploy routers, switches, and network appliance
network appliance devices to construct its internal network, DMZ, devices to construct its internal network, DMZ, and external network
and external network access; it may have many servers and storage access; it may have many servers and storage running various
running various applications. With NVO3 technology, a DC Provider applications. With NVO3 technology, a DC provider can construct a
can construct a virtual Data Center (vDC) over its physical DC vDC over its physical DC infrastructure and offer a vDC service to
infrastructure and offer a virtual Data Center service to enterprise enterprise customers. A vDC at the DC provider site provides the
customers. A vDC at the DC Provider site provides the same same capability as the physical DC at a customer site. A customer
capability as the physical DC at a customer site. A customer manages manages its own applications running in its vDC. A DC provider can
its own applications running in its vDC. A DC Provider can further further offer different network service functions to the customer.
offer different network service functions to the customer. The The network service functions may include a firewall, DNS, LB,
network service functions may include firewall, DNS, load balancer,
gateway, etc. gateway, etc.
Figure 2 below illustrates one such scenario at the service Figure 2 illustrates one such scenario at the service-abstraction
abstraction level. In this example, the vDC contains several L2 VNs level. In this example, the vDC contains several L2 VNs (L2VNx,
(L2VNx, L2VNy, L2VNz) to group the tenant systems together on a per- L2VNy, L2VNz) to group the tenant systems together on a per-
application basis, and one L3 VN (L3VNa) for the internal routing. A application basis, and one L3 VN (L3VNa) for the internal routing. A
network firewall and gateway runs on a VM or server that connects to network firewall and gateway runs on a VM or server that connects to
L3VNa and is used for inbound and outbound traffic processing. A L3VNa and is used for inbound and outbound traffic processing. An LB
load balancer (LB) is used in L2VNx. A VPN is also built between the is used in L2VNx. A VPN is also built between the gateway and
gateway and enterprise router. An Enterprise customer runs enterprise router. An Enterprise customer runs Web/Mail/Voice
Web/Mail/Voice applications on VMs within the vDC. The users at the applications on VMs within the vDC. The users at the Enterprise site
Enterprise site access the applications running in the vDC via the access the applications running in the vDC via the VPN; Internet
VPN; Internet users access these applications via the users access these applications via the gateway/firewall at the DC
gateway/firewall at the provider DC site. provider site.
Internet ^ Internet Internet ^ Internet
| |
^ +--+---+ ^ +--+---+
| | GW | | | GW |
| +--+---+ | +--+---+
| | | |
+-------+--------+ +--+---+ +-------+--------+ +--+---+
|Firewall/Gateway+--- VPN-----+router| |Firewall/Gateway+--- VPN-----+router|
+-------+--------+ +-+--+-+ +-------+--------+ +-+--+-+
| | | | | |
...+.... |..| ...+.... |..|
+-------: L3 VNa :---------+ LANs +-------: L3 VNa :---------+ LANs
+-+-+ ........ | +-+-+ ........ |
|LB | | | Enterprise Site |LB | | | Enterprise Site
+-+-+ | | +-+-+ | |
...+... ...+... ...+... ...+... ...+... ...+...
: L2VNx : : L2VNy : : L2VNz : : L2VNx : : L2VNy : : L2VNz :
....... ....... ....... ....... ....... .......
|..| |..| |..| |..| |..| |..|
| | | | | | | | | | | |
Web App. Mail App. VoIP App. Web App. Mail App. VoIP App.
Provider DC Site DC Provider Site
Figure 2 - Virtual Data Center Abstraction View Figure 2: Virtual Data Center Abstraction View
The enterprise customer decides which applications should be The enterprise customer decides which applications should be
accessible only via the intranet and which should be assessable via accessible only via the intranet and which should be assessable via
both the intranet and Internet, and configures the proper security both the intranet and Internet, and it configures the proper security
policy and gateway function at the firewall/gateway. Furthermore, an policy and gateway function at the firewall/gateway. Furthermore, an
enterprise customer may want multi-zones in a vDC (See section 4.2) enterprise customer may want multi-zones in a vDC (see Section 4.2)
for the security and/or the ability to set different QoS levels for for the security and/or the ability to set different QoS levels for
the different applications. the different applications.
The vDC use case requires an NVO3 solution to provide DC operators The vDC use case requires an NVO3 solution to provide DC operators
with an easy and quick way to create an NVO3 virtual network and with an easy and quick way to create an NVO3 virtual network and NVEs
NVEs for any vDC design, to allocate TSs and assign TSs to the for any vDC design, to allocate TSs and assign TSs to the
corresponding NVO3 virtual network, and to illustrate vDC topology corresponding NVO3 virtual network and to illustrate vDC topology and
and manage/configure individual elements in the vDC in a secure way. manage/configure individual elements in the vDC in a secure way.
5. Summary 5. Summary
This document describes some general NVO3 use cases in DCs. The This document describes some general NVO3 use cases in DCs. The
combination of these cases will give operators the flexibility and combination of these cases will give operators the flexibility and
capability to design more sophisticated support for various cloud capability to design more sophisticated support for various cloud
applications. applications.
DC services may vary, NVO3 virtual networks make it possible to DC services may vary, NVO3 virtual networks make it possible to scale
scale a large number of virtual networks in DC and ensure the a large number of virtual networks in a DC and ensure the network
network infrastructure not impacted by the number of VMs and dynamic infrastructure not impacted by the number of VMs and dynamic workload
workload changes in DC. changes in a DC.
NVO3 uses tunnel techniques to deliver NVO3 traffic over DC physical NVO3 uses tunnel techniques to deliver NVO3 traffic over DC physical
infrastructure network. A tunnel encapsulation protocol is infrastructure network. A tunnel encapsulation protocol is
necessary. An NVO3 tunnel may in turn be tunneled over other necessary. An NVO3 tunnel may, in turn, be tunneled over other
intermediate tunnels over the Internet or other WANs. intermediate tunnels over the Internet or other WANs.
An NVO3 virtual network in a DC may be accessed by external users in An NVO3 virtual network in a DC may be accessed by external users in
a secure way. Many existing technologies can help achieve this. a secure way. Many existing technologies can help achieve this.
6. Security Considerations 6. Security Considerations
Security is a concern. DC operators need to provide a tenant with a Security is a concern. DC operators need to provide a tenant with a
secured virtual network, which means one tenant's traffic is secured virtual network, which means one tenant's traffic is isolated
isolated from other tenants' traffic and is not leaked to the from other tenants' traffic and is not leaked to the underlay
underlay networks. Tenants are vulnerable to observation and data networks. Tenants are vulnerable to observation and data
modification/injection by the operator of the underlay and should modification/injection by the operator of the underlay and should
only use operators they trust. DC operators also need to prevent a only use operators they trust. DC operators also need to prevent a
tenant application attacking their underlay DC network; further, tenant application attacking their underlay DC networks; further,
they need to protect a tenant application attacking another tenant they need to protect a tenant application attacking another tenant
application via the DC infrastructure network. For example, a tenant application via the DC infrastructure network. For example, a tenant
application attempts to generate a large volume of traffic to application attempts to generate a large volume of traffic to
overload the DC's underlying network. This can be done by limiting overload the DC's underlying network. This can be done by limiting
the bandwidth of such communications. the bandwidth of such communications.
7. IANA Considerations 7. IANA Considerations
This document does not request any action from IANA. This document does not require any IANA actions.
8. Informative References 8. Informative References
[IEEE802.1Q] IEEE, "IEEE Standard for Local and metropolitan area [IEEE802.1Q] IEEE, "IEEE Standard for Local and metropolitan area
networks -- Media Access Control (MAC) Bridges and Virtual networks -- Media Access Control (MAC) Bridges and
Bridged Local Area", IEEE Std 802.1Q, 2011. Virtual Bridged Local Area Networks", IEEE Std
802.1Q-2011, DOI 10.1109/IEEESTD.2011.6009146.
[NIST] National Institute of Standards and Technology, "The NIST [NVO3MCAST] Ghanwani, A., Dunbar, L., McBride, M., Bannai, V., and
Definition of Cloud Computing", SP 880-145, September, R. Krishnan, "A Framework for Multicast in Network
2011. Virtualization Overlays", Work in Progress,
draft-ietf-nvo3-mcast-framework-07, May 2016.
[NVO3MCAST] Ghanwani, A., Dunbar, L., et al, "A Framework for [RFC1035] Mockapetris, P., "Domain names - implementation and
Multicast in Network Virtualization Overlays", draft-ietf- specification", STD 13, RFC 1035,
nvo3-mcast-framework-05, work in progress. DOI 10.17487/RFC1035, November 1987,
<http://www.rfc-editor.org/info/rfc1035>.
[RFC1035] Mockapetris, P., "DOMAIN NAMES - Implementation and [RFC3022] Srisuresh, P. and K. Egevang, "Traditional IP Network
Specification", RFC1035, November 1987. Address Translator (Traditional NAT)", RFC 3022,
DOI 10.17487/RFC3022, January 2001,
<http://www.rfc-editor.org/info/rfc3022>.
[RFC3022] Srisuresh, P. and Egevang, K., "Traditional IP Network [RFC4301] Kent, S. and K. Seo, "Security Architecture for the
Address Translator (Traditional NAT)", RFC3022, January Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
2001. December 2005,
<http://www.rfc-editor.org/info/rfc4301>.
[RFC4301] Kent, S., "Security Architecture for the Internet [RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
Protocol", rfc4301, December 2005 Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364,
February 2006,
<http://www.rfc-editor.org/info/rfc4364>.
[RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private [RFC7348] Mahalingam, M., Dutt, D., Duda, K., Agarwal, P.,
Networks (VPNs)", RFC 4364, February 2006. Kreeger, L., Sridhar, T., Bursell, M., and C. Wright,
"Virtual eXtensible Local Area Network (VXLAN): A
Framework for Overlaying Virtualized Layer 2 Networks
over Layer 3 Networks", RFC 7348,
DOI 10.17487/RFC7348, August 2014,
<http://www.rfc-editor.org/info/rfc7348>.
[RFC7348] Mahalingam, M., Dutt, D., et al, "Virtual eXtensible Local [RFC7364] Narten, T., Ed., Gray, E., Ed., Black, D., Fang, L.,
Area Network (VXLAN): A Framework for Overlaying Kreeger, L., and M. Napierala, "Problem Statement:
Virtualized Layer 2 Networks over Layer 3 Networks", Overlays for Network Virtualization", RFC 7364,
RFC7348 August 2014. DOI 10.17487/RFC7364, October 2014,
<http://www.rfc-editor.org/info/rfc7364>.
[RFC7364] Narten, T., et al "Problem Statement: Overlays for Network [RFC7365] Lasserre, M., Balus, F., Morin, T., Bitar, N., and Y.
Virtualization", RFC7364, October 2014. Rekhter, "Framework for Data Center (DC) Network
Virtualization", RFC 7365, DOI 10.17487/RFC7365,
October 2014,
<http://www.rfc-editor.org/info/rfc7365>.
[RFC7365] Lasserre, M., Motin, T., et al, "Framework for DC Network [RFC7432] Sajassi, A., Ed., Aggarwal, R., Bitar, N., Isaac, A.,
Virtualization", RFC7365, October 2014. Uttaro, J., Drake, J., and W. Henderickx, "BGP MPLS-
Based Ethernet VPN", RFC 7432, DOI 10.17487/RFC7432,
February 2015,
<http://www.rfc-editor.org/info/rfc7432>.
[RFC7432] Sajassi, A., Ed., Aggarwal, R., Bitar, N., Isaac, A. and [RFC7637] Garg, P., Ed., and Y. Wang, Ed., "NVGRE: Network
J. Uttaro, "BGP MPLS Based Ethernet VPN", RFC7432, Virtualization Using Generic Routing Encapsulation",
February 2015 RFC 7637, DOI 10.17487/RFC7637, September 2015,
<http://www.rfc-editor.org/info/rfc7637>.
[RFC7637] Garg, P., and Wang, Y., "NVGRE: Network Virtualization [RFC8014] Black, D., Hudson, J., Kreeger, L., Lasserre, M., and
using Generic Routing Encapsulation", RFC7637, Sept. 2015. T. Narten, "An Architecture for Data-Center Network
Virtualization over Layer 3 (NVO3)", RFC 8014,
DOI 10.17487/RFC8014, December 2016,
<http://www.rfc-editor.org/info/rfc8014>.
[RFC8014] Black, D., et al, "An Architecture for Overlay Networks [VRF-LITE] Cisco, "Configuring VRF-lite",
(NVO3)", rfc8014, January 2017. <http://www.cisco.com/c/en/us/td/docs/switches/lan/
catalyst4500/12-2/31sg/configuration/guide/conf/
vrf.pdf>.
[VRF-LITE] Cisco, "Configuring VRF-lite", http://www.cisco.com Acknowledgements
The authors would like to thank Sue Hares, Young Lee, David Black,
Pedro Marques, Mike McBride, David McDysan, Randy Bush, Uma Chunduri,
Eric Gray, David Allan, Joe Touch, Olufemi Komolafe, Matthew Bocci,
and Alia Atlas for the reviews, comments, and suggestions.
Contributors Contributors
David Black David Black
Dell EMC Dell EMC
176 South Street 176 South Street
Hopkinton, MA 01748 Hopkinton, MA 01748
David.Black@dell.com United States of America
Vinay Bannai Email: David.Black@dell.com
PayPal
2211 N. First St,
San Jose, CA 95131
Phone: +1-408-967-7784
Email: vbannai@paypal.com
Ram Krishnan Vinay Bannai
Brocade Communications PayPal
San Jose, CA 95134 2211 N. First Street
Phone: +1-408-406-7890 San Jose, CA 95131
Email: ramk@brocade.com United States of America
Kieran Milne Phone: +1-408-967-7784
Juniper Networks Email: vbannai@paypal.com
1133 Innovation Way
Sunnyvale, CA 94089
Phone: +1-408-745-2000
Email: kmilne@juniper.net
Acknowledgements Ram Krishnan
Brocade Communications
San Jose, CA 95134
United States of America
Authors like to thank Sue Hares, Young Lee, David Black, Pedro Phone: +1-408-406-7890
Marques, Mike McBride, David McDysan, Randy Bush, Uma Chunduri, Eric Email: ramk@brocade.com
Gray, David Allan, Joe Touch, Olufemi Komolafe, Matthew Bocci, and
Alia Atlas for the review, comments, and suggestions.
Authors' Addresses Kieran Milne
Juniper Networks
1133 Innovation Way
Sunnyvale, CA 94089
United States of America
Phone: +1-408-745-2000
Email: kmilne@juniper.net
Authors' Addresses
Lucy Yong Lucy Yong
Huawei Technologies Huawei Technologies
Phone: +1-918-808-1918 Phone: +1-918-808-1918
Email: lucy.yong@huawei.com Email: lucy.yong@huawei.com
Linda Dunbar Linda Dunbar
Huawei Technologies, Huawei Technologies,
5340 Legacy Dr. 5340 Legacy Drive
Plano, TX 75025 US Plano, TX 75025
United States of America
Phone: +1-469-277-5840 Phone: +1-469-277-5840
Email: linda.dunbar@huawei.com Email: linda.dunbar@huawei.com
Mehmet Toy Mehmet Toy
Verizon Verizon
E-mail : mtoy054@yahoo.com Email: mehmet.toy@verizon.com
Aldrin Isaac Aldrin Isaac
Juniper Networks Juniper Networks
E-mail: aldrin.isaac@gmail.com 1133 Innovation Way
Sunnyvale, CA 94089
United States of America
Email: aldrin.isaac@gmail.com
Vishwas Manral Vishwas Manral
Nano Sec Co
3350 Thomas Rd.
Santa Clara, CA
United States of America
Email: vishwas@ionosnetworks.com Email: vishwas@nanosec.io
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