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Versions: 01 02 03

INTERNET-DRAFT                                               Luyuan Fang
Intended Status: Standards track                              John Evans
Expires: April 18, 2014                                       David Ward
                                                            Rex Fernando
                                                           John Mullooly
                                                                   Cisco
                                                                 Ning So
                                                     Tata Communications
                                                             Nabil Bitar
                                                                 Verizon
                                                         Maria Napierala
                                                                    AT&T

                                                        October 18, 2013

                       BGP/MPLS IP VPN Virtual CE
                     draft-fang-l3vpn-virtual-ce-02

Abstract

   This document describes the architecture and solutions of using
   virtual Customer Edge (vCE) of BGP IP MPLS VPN. The solution is aimed
   at providing efficient service delivery capability through CE
   virtualization, and is especially beneficial in virtual Private Cloud
   (vPC) environments for extending BGP/MPLS IP VPN into tenant virtual
   Data Center containers.

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/1id-abstracts.html

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html




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Copyright and License Notice

   Copyright (c) 2013 IETF Trust and the persons identified as the
   document authors. All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document. Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document. Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
     1.1 Terminology  . . . . . . . . . . . . . . . . . . . . . . . .  4
     1.2 Problem statement  . . . . . . . . . . . . . . . . . . . . .  5
     1.3 Scope of the document  . . . . . . . . . . . . . . . . . . .  6
   2. Virtual CE Architecture and Reference Model . . . . . . . . . .  6
     2.1 Virtual CE . . . . . . . . . . . . . . . . . . . . . . . . .  6
     2.2 Architecture . . . . . . . . . . . . . . . . . . . . . . . .  7
   3. Control Plane . . . . . . . . . . . . . . . . . . . . . . . . . 10
     3.1 vCE Control Plane  . . . . . . . . . . . . . . . . . . . . . 10
   4. Forwarding Plane  . . . . . . . . . . . . . . . . . . . . . . . 10
     4.1 Forwarding between vCE and PE/vPE  . . . . . . . . . . . . . 11
     4.2 Forwarding between vCE and VM  . . . . . . . . . . . . . . . 11
   5. Addressing and QoS  . . . . . . . . . . . . . . . . . . . . . . 11
     5.1 Addressing . . . . . . . . . . . . . . . . . . . . . . . . . 11
     5.2 QoS  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
   6.  Management plane . . . . . . . . . . . . . . . . . . . . . . . 12
     6.1 Network abstraction and management . . . . . . . . . . . . . 12
     6.2 Service VM Management  . . . . . . . . . . . . . . . . . . . 12
   7. Orchestration and IP VPN inter-provisioning . . . . . . . . . . 12
     7.1 DC Instance to WAN BGP/MPLS IP VPN instance "binding"
         Requirements . . . . . . . . . . . . . . . . . . . . . . . . 12
     7.2. Provisioning/Orchestration  . . . . . . . . . . . . . . . . 13
       7.2.1 vCE Push model . . . . . . . . . . . . . . . . . . . . . 13
         7.2.1.1 Inter-domain provisioning vCE Push Model . . . . . . 14
         7.2.1.2 Cross-domain provisioning vCE Push Model . . . . . . 14
       7.1.1 vCE Pull model . . . . . . . . . . . . . . . . . . . . . 15
   8. Security Considerations . . . . . . . . . . . . . . . . . . . . 16
   9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 16
   10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16
     10.1  Normative References . . . . . . . . . . . . . . . . . . . 16
     10.2  Informative References . . . . . . . . . . . . . . . . . . 17



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   11. Acknowledgement  . . . . . . . . . . . . . . . . . . . . . . . 17
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18

















































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1.  Introduction

   In the typical enterprise BGP/MPLS IP VPN [RFC4364] deployment, the
   Provider Edge (PE) and Customer Edge (CE) are physical routers which
   support the PE and CE functions. With the recent development of cloud
   services, using virtual instances of PE or CE functions, which reside
   in a compute device such as a server, can be beneficial to emulate
   the same logical functions as the physical deployment model but now
   achieved via cloud based network virtualization principles. This
   would be considered as part of the Network functions Virtualization
   (NFV) effort.

   This document describes BGP/MPLS IP VPN virtual CE (vCE) solutions,
   while Virtual PE (vPE) concept and implementation options are
   discussed in [I-D.fang-l3vpn-virtual-pe],
   [I-D.ietf-l3vpn-end-system]. vPE and vCE solutions provide two
   avenues to realize network virtualization.

1.1 Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

   Term              Definition
   -----------       --------------------------------------------------
   AAA               Authentication, Authorization, and Accounting
   ACL               Access Control List
   AS                Autonomous Systems
   ASBR              Autonomous Systems Border Router
   BGP               Border Gateway Protocol
   CE                Customer Edge
   DB                Data Base
   DMZ               Demilitarized Zone, a.k.a. perimeter networking
   FE                Front End
   FTP               File Transfer Protocol
   GRE               Generic Routing Encapsulation
   HTTP              Hypertext Transfer Protocol
   Hypervisor        Virtual Machine Manager
   I2RS              Interface to Routing System
   LDAP              Lightweight Directory Access Protocol
   MP-BGP            Multi-Protocol Border Gateway Protocol
   NAT               Network Address Translation
   NVGRE             Network Virtualization using GRE
   PE                Provider Edge
   QinQ              Provider Bridging, stacked VLANs
   RR                Route Reflector
   SDN               Software Defined Network



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   SLA               Service Level Agreement
   SMTP              Simple Mail Transfer Protocol
   ToR               Top of the Rack switch
   vCE               virtual Customer Edge Router
   vLB               virtual Load Balancer
   VM                Virtual Machine
   VLAN              Virtual Local Area Network
   vPE               virtual Provider Edge Router
   VPN               Virtual Private Network
   vSG               virtual Security Gateway
   VXLAN             Virtual eXtensible Local Area Network
   WAN               Wide Area Network

   Virtual CE (vCE): A virtual instance of the Customer Edge (CE)
   routing function which resides in one or more network or compute
   devices. For example, the vCE data plane may reside in an end device,
   such as a server, and as co-resident with application Virtual
   Machines (VMs) on the server; the vCE control plane may reside in the
   same device or in a separate entity such as a controller.

   End device: A device where Guest OS, Host OS/Hypervisor,
   applications, VMs, and virtual router may reside.

   Network Container/Tenant Container: An abstraction of a set of
   network and compute resources which can be physical and virtual,
   providing the cloud services for a tenant. One tenant can have more
   than one Tenant Containers.

   Zone: A logical grouping of VMs and service assets within a tenant
   container.  Different security policies may be applied within and
   between zones.

   DMZ: Demilitarized zone, a.k.a. perimeter networking. It is often a
   machine or a small subnet that sits between a trusted internal
   network, such as a corporate private LAN, and an un-trusted external
   network, such as the public Internet. Typically, the DMZ contains
   devices accessible to Internet traffic, such as Web (HTTP) servers,
   FTP servers, SMTP (e-mail) servers and DNS servers.

1.2 Problem statement

   With the growth of cloud services and the increase in the number of
   CE devices, routers/switches, and appliances, such as Firewalls (FWs)
   and Load Balancers (LBs), that need to be supported, it is beneficial
   to virtualize the Data Center tenant container. The virtualized
   container can increase resource sharing, optimize routing and
   forwarding of inter-segment and inter-service traffic, and allow
   simplified design, provisioning, and management.



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   The following two aspects of the virtualized Data Center tenant
   container for the IP VPN CE solution are discussed in this document.

   1. Architecture re-design for virtualized DC.

   The optimal architecture of the virtualized container includes
   virtual CE, virtual appliances, and application VMs. All these
   functions are co-residents on virtualized servers. CEs and appliances
   can be created and removed easily on demand, and the virtual CE can
   interconnect the virtual appliances (e.g., FW, LB, NAT), applications
   (e.g., Web, App., and DB) in a co-located fashion for simplicity,
   routing/forwarding optimization, and easier service chaining.
   Virtualizing these functions on a per-tenant basis provides
   simplicity for the network operator in regards to managing per tenant
   service orchestration, tenant container moves, capacity planning
   across tenants and per-tenant policies.

   2. Provisioning/orchestration. Two issues need to be addressed:

   a) The provisioning/orchestration system of the virtualized data
   center need to support VM life cycle and VM migration.

   b) The provisioning/orchestration systems of the DC and the WAN
   networks need to be coordinated to support end-to-end BGP/MPLS IP VPN
   from DC to DC or from DC to enterprise remote offices in the same
   VPN. The DC and the WAN network are often operated by separate
   departments, even if they belong to the same provider. Today, the
   process of inter-connecting is often slow and painful, and automation
   is highly desirable.

1.3 Scope of the document

   As the majority (all in some networks) of applications are IP, this
   vCE solution is focusing on IP VPN solutions to cover the most common
   cases and keep matters as simple as possible.

2. Virtual CE Architecture and Reference Model

2.1 Virtual CE

   As described in [RFC4364], IP uses a "peer model" - the customers'
   edge routers (CE routers) exchange routes with the Service Provider's
   edge routers (PE routers); the CEs do not peer with each other. MP-
   BGP [RFC4271, RFC4760] is used between the PEs (often with RRs) which
   have a particular VPN attached to them to exchange the VPN routes. A
   CE sends IP packets to the PE; no VPN labels for packets forwarded
   between CE and PE.




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   A virtual CE (vCE) is a software instance of BGP/MPLS IP VPN CE
   function which can reside in ANY network or compute devices. For
   example, a vCE MAY reside in an end device, such as a server in a
   Data Center, where the application VMs reside.

   Using the virtual CE model, the CE functions CAN easily co-located
   with the VM/applications, e.g., in the same server. This allows
   tenant inter-segment and inter-service routing to be optimized.
   Likewise the vCE can be in a separate server (in the same DC rack or
   across racks) than the application VMs, in which case VMs would
   typically use standard L2 technologies to access the vCE via the DC
   network.

   Similar to the virtual PE solution, the control and forwarding of a
   virtual CE can be on the same device, or decoupled and reside on
   different physical devices. The provisioning of a virtual CE,
   associated applications, and the tenant network container can be
   supported through DC orchestration systems.

   Unlike a physical or virtual PE which can support multi-tenants, a
   physical or virtual CE supports a single tenant only. A single tenant
   CAN use multiple physical or virtual CEs. An end device, such as a
   server, CAN support one or more vCE(s). While the vCE is defined as a
   single tenant device, each tenant can have multiple logical
   departments which are under the tenant administrative control,
   requiring logical separation, this is the same model as today's
   physical CE deployments.

   vCE and vPE are complimentary approaches for extending IP VPN into
   tenant containers. In the vCE solution, there is no BGP/MPLS IP VPN
   within the data center or other type of service network, the vCE can
   connect to the PE which is a centralized BGP/MPLS IP VPN PE/ASBR/DC
   Gateway, or connect to distributed vPE on a server or on the Top of
   the Rack switch (ToR). vCE can be used to extend the existing SP
   managed CE solution to create new cloud enabled services and provide
   the same topological model and features that are consistent with the
   physical CE systems.

2.2 Architecture

   Figure 1 illustrates the topology where vCE is resident in the
   servers where the applications are hosted.









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                         .''---'''---''.
                        (               )
                       (     IP/MPLS     )
                        (      WAN      )
          WAN             '--,,,_,,,--'
          ----------------|----------|------------------
          Service/DC      |          |
          Network     +-------+   +-------+
                      |Gateway|---|Gateway|
                      |  PE   |   |  PE   |
                      +-------+   +-------+
                          |    ,---. |
                        .---. (     '.---.
                       (     '      '     ')
                     ('     Data Center     )
                      (.      Fabric      .)
                        (     (       ).--'
                     /   ''--' '-''--'       \
                   /      /          \        \
           +-------+   +---+---+   +-------+   +-------+
           |  vCE  |   |vCE|vCE|   |  vCE  |   |vCE|vCE|
           +---+---+   +---+---+   +---+---+   +---+---+
           |VM |VM |   |VM |VM |   |VM |VM |   |VM |VM |
           +---+---+   +---+---+   +---+---+   +---+---+
           |VM |VM |   |VM |VM |   |VM |VM |   |VM |VM |
           +---+---+   +---+---+   +---+---+   +---+---+

           End Device  End Device  End Device  End Device

           Figure 1. Virtualized Data Center with vCE


   Figure 1 above illustrate a vCE solution in a virtualized Data Center
   with application VMs on the servers. One or more vCEs MAY be used on
   each server.

   The vCEs logically connect to the PEs/Gateway to join the particular
   BGP/MPLS IP VPN which the tenant belongs to. Gateway PEs connect to
   the BGP/MPLS IP VPN in the WAN network for inter-DC and DC to
   enterprise VPN sites connection. The server physically connects to
   the DC Fabric for packet forwarding.










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                        ,---.                  ,---.
                   .--.(     )            .--.(     )
                  (     '   '.---.       (     '   '.---.
                 ('     L3VPN     )     ('   Internet    )
                  '..(         ).'       '..(         ).'
                      '--'---''              '--'---''
                   +---+   +---+          +---+   +---+
                   |PE |   |PE |          | R |   | R |
                   +---+   +---+          +---+   +---+
                     |       |              |       |
   """"""""""""""""""|"""""""|""""""""""""""|"""""""|"""""""""""""""""
   " End Device      |       |            +----+    |                "
   " (e.g. a server) +-------+-----+ +----|vSG |----+                "
   "                               | |    +----+                     "
   "                              +----+                             "
   "        +---------------------|vCE |-----------+                 "
   "        |                     +----+           |                 "
   " +----+ |   +----+              |              |  +----+         "
   " |vLB |-|   |vLB |--+-----------+              +--|vLB |         "
   " +----+ |   +----+  |                          |  +----+         "
   "        |           |                   +----+ |                 "
   "        |           |            +------|vSG |-+------+          "
   "        |           |            |      +----+        |          "
   " '''''''|'''''''''''|''''' ''''''|'''''''''|''''''''''|''''''''' "
   " ' +--------+ +--------+ ' ' +-------+ +-------+ +-----------+ ' "
   " ' | Apps/  | | Apps/  | ' ' | Apps/ | | Apps/ | |Apps |Apps | ' "
   " ' | VMs    | | VMs    | ' ' | VMs   | | VMs   | |VMs  |VMs  | ' "
   " ' |        | |        | ' ' |       | |       | |ZONE3|ZONE4| ' "
   " ' | Public | |Protect-| ' ' |       | |       | +-----+-----+ ' "
   " ' | Zone   | | ed FE  | ' ' | ZONE1 | | ZONE2 | |Apps |Apps | ' "
   " ' | (DMZ)  | |        | ' ' |       | |       | |VMs  |VMs  | ' "
   " ' |        | |        | ' ' |       | |       | |ZONE5|ZONE6| ' "
   " ' +--------+ +--------+ ' ' +-------+ +-------+ +-----------+ ' "
   " '     Front-end Zone    ' '           Back-end Zone           ' "
   " '                       ' '                                   ' "
   " ''''''''''''''''''''''''' ''''''''''''''''''''''''''''''''''''' "
   """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""

        Figure 2. A Virtualized Container with vCE in an End Device

   An end device shown in Figure 2 is a physical server supporting
   multiple virtualized appliances and applications, and hosts multiple
   client VMs.

   In the traditional deployment, the topology often involves multiple
   physical CEs, physical Security Gateways and Load Balancers residing
   in the same Data Center.




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   The virtualized approach provides the benefit of reduced number of
   physical devices, simplified management, optimal routing due to the
   co-location of vCE, services, and client VMs.

   While the above diagram represents a simplified view of all of the
   tenant service and application VMs residing in the same physical
   server, the above model can also be represented with the VMs spread
   across many physical servers and the DC network would provide the
   physical inter-connectivity while the vCE and the VMs connected to
   the vCE form the logical connections.

3. Control Plane

3.1 vCE Control Plane

   The vCE control plane can be distributed or centralized.

   1) Distributed control plane

   vCE CAN exchange BGP routes with PE or vPE for the particular
   BGP/MPLS IP VPN as described in [RFC4364]. The vCE must support BGP
   if this approach is used.

   The advantage of using distributed protocols is to avoid single point
   of failure and bottleneck. Service chaining can be easily and
   efficiently supported in this approach.

   BGP as PE-CE protocol is used in majority deployment in typical
   Enterprise BGP/MPLS IP VPN PE-CE connections. BGP supports rich
   policy compared to other alternatives.

   2) Static routing. It is also used in Enterprise BGP/MPLS IP VPN PE-
   CE connections based on past observation. It MAY be used if the
   operator prefers.

   2. Using controller approach

   Controller can be used as part of the Software Defined Network (SDN)
   approach. A controller can be distributed or centralized, or
   physically distributed and logically centralized. The controller
   performs the control plane functions, and sends instructions to the
   vCE on the end devices to configure the data plane.

   This requires standard interface to routing system (I2RS). The
   Interface to Routing System (I2RS) is work in progress in IETF
   [I-D.ietf-i2rs-architecture], [I-D.ietf-i2rs-problem-statement].

4. Forwarding Plane



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4.1 Forwarding between vCE and PE/vPE

   No MPLS forwarding is required between PE and CE in typical PE-CE
   connection scenarios, though MPLS label forwarding is required for
   implementing Carriers' Carrier (CSC) model.

   IPv4 and IPv6 packet forwarding MUST be supported.

   Native fabric CAN be used to support isolation between vCEs to PE
   connections.

   Examples of native fabric include:

         - VLANs [IEEE 802.1Q], Virtual Local Area Network

         - IEEE 802.1ad [IEEE 802.1ad]/QinQ, Provider Bridge

         Or overlay segmentation with better scalability:

         - VXLANs, Virtual Extensible LAN, work in progress in IETF,
         [I-D.mahalingam-dutt-dcops-vxlan].

         - NVGRE, Network Virtualization using GRE, work in progress in
         IETF [I-D.sridharan-virtualization-nvgre].

4.2 Forwarding between vCE and VM

   If the vCE and the VM that the vCE is connecting are co-located in
   the same server, the connection is internal to the server, no
   external protocol involved.

   If the vCE and the VM that the vCE is connecting are located in
   different devices, standard external protocols are needed. The
   forwarding can be native or overlay techniques as listed in the above
   sub-section.

5. Addressing and QoS

5.1 Addressing

   IPv4 and IPv6 addressing MUST be supported.

   IP address allocation for vCEs and applications/client:

      1) IP address MAY be assigned by central management/provisioning
         with predetermined blocks through planning process.

      2) IP address MAY be obtained through DHCP server.



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   Address space separation: The IP addresses used for clients in the
   BGP/MPLS IP VPNs in the DC SHOULD be in separate address blocks
   outside the blocks used for the underlay infrastructure of the DC.
   The purpose is to protect the DC fabric from being attacked if the
   attacker gain access of the tenant VPNs.

5.2 QoS

   Differentiated Services [RFC2475] Quality of Service (QoS) is
   standard functionality for physical CEs and MUST be supported on vCE.
   This is important to ensure seamless end-to-end SLA from BGP/MPLS IP
   VPN in the WAN into service network/Data center. The use of MPLS
   Diffserv tunnel model Pipe Mode (RFC3270) with explicit null LSP must
   be supported.

6.  Management plane

6.1 Network abstraction and management

   The use of vCE with single tenant virtual service instances can
   simplify management requirements as there is no need to discover
   device capabilities, track tenant dependencies and manage service
   resources.

   vCE North bound interface SHOULD be standards based.

   The programmatic interface are currently under definition in the
   IETF's Interface to Routing Systems (I2RS) initiative,
   [I-D.ietf-i2rs-architecture], [I-D.ietf-i2rs-problem-statement].

   vCE element management MUST be supported, it can be in the similar
   fashion as for physical CE, without the hardware aspects.

6.2 Service VM Management

   Service VM Management SHOULD be hypervisor agnostic, e.g., on demand
   service VMs turning-up SHOULD be supported.

   The management tools SHOULD be open standards.

7. Orchestration and IP VPN inter-provisioning

7.1 DC Instance to WAN BGP/MPLS IP VPN instance "binding" Requirements

   - MUST support service activation in the physical and virtual
   environment.

     For example, assign VLAN to correct VRF.



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   - MUST support per VLAN Authentication, Authorization, and Accounting
   (AAA).

     The PE function is an OAM boundary.

   - MUST be able to apply other policies to VLAN.

     For example, per VLAN QOS, ACLs.

   - MUST ensure that WAN BGP/MPLS IP VPN state and DC state are
   dynamically synchronized.

     Ensure that there is no possibility of customer being connected to
   the wrong VRF. For example, remove all tenant state when service an
   instance is terminated.

   - MUST integrate with existing WAN BGP/MPLS IP VPN provisioning
   processes.

   - MUST scale to 10,000 or higher tenant service instances.

   - MUST cope with rapid (sub minute) tenant mobility.

   - SHOULD support automated cross provisioning accounting correlation
   between WAN BGP/MPLS IP VPN and Cloud/DC for the same tenant.

   - MAY support Automated cross provisioning state correlation between
   WAN BGP/MPLS IP VPN and Cloud/DC for the same tenant.

7.2. Provisioning/Orchestration

   There are two primary approaches for IP VPN provisioning - push and
   pull, both CAN be used for provisioning/orchestration.

7.2.1 vCE Push model

   Push model: It is a top down approach - push IP VPN provisioning from
   network management system or other central control provisioning
   systems to the IP VPN network elements.

   This approach supports service activation and it is commonly used in
   the existing BGP/MPLS IP VPN enterprise deployment. When extending
   BGP/MPLS IP VPN solution into the Cloud/DC, it MUST support off-line
   accounting correlation between the WAN BGP/MPLS IP VPN and the
   Cloud/DC IP VPN for the tenant, the systems SHOULD be able to bind
   interface accounting to particular tenant. It MAY requires offline
   state correlation as well, for example, bind interface state to
   tenant.



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7.2.1.1 Inter-domain provisioning vCE Push Model

   Provisioning process:

   1) Cloud/DC orchestrator configures vCE.

   2) Orchestrator initiates WAN IP VPN provisioning; passes connection
   IDs (e.g., of VLAN/VXLAN/NVGRE) and tenant context to WAN IP VPN
   provisioning systems.

   3) WAN IP VPN provisioning system provisions PE VRF and other
   policies per normal enterprise IP VPN provisioning processes.

   This model requires the following:

   - The DC orchestration system or the WAN IP VPN provisioning system
     know the topology inter-connecting the DC and WAN VPN. For
     example, which interface on the WAN core device connects to which
     interface on the DC PE.

   - Offline state correlation.

   - Offline accounting correlation.

   - Per SP integration.

   Dynamic BGP session between PE/vPE and vCE MAY be used to automate
   the PE provisioning in the PE-vCE model, that will remove the needs
   for PE  configuration. Other protocols can be used for this purpose
   as well, for example, use Enhanced Interior Gateway Routing Protocol
   (EIGRP) for dynamic neighbour relationship establishment.

   The dynamic routing prevents the needs to configure the PEs in PE-vCE
   model.

   Caution: This is only under the assumption that the DC provisioning
   system is trusted and could support dynamic establishment of PE-vCE
   BGP neighbor relationships, for example, the WAN network and the
   cloud/DC belongs to the same SP.

7.2.1.2 Cross-domain provisioning vCE Push Model

   Provisioning Process:

   1) Cross-domain orchestration system initiates DC orchestration.

   2) DC orchestration system configures vCE.




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   3) DC orchestration system passes back VLAN/VXLAN/NVGRE and tenant
   context.
      to cross-domain orchestration system

   4) Cross-domain orchestration system initiates WAN IP VPN
      provisioning.

   5) WAN IP VPN provisioning system provisions PE VRF and other
      policies as per normal enterprise IP VPN provisioning processes.

   This model requires the following:

   - Cross-domain orchestration system knows the topology connecting the
   DC and WAN IP VPN, for example, which interface on core device
   connects to which interface on DC PE.

   - Offline state correlation.

   - Offline accounting correlation.

   - Per SP integration.

7.1.1 vCE Pull model

   Pull model: It is a bottom-up approach - pull from network elements
   to network management/AAA based upon data plane or control plane
   activity. It supports service activation, this approach is often used
   in broadband deployment. Dynamic accounting correlation and dynamic
   state correlation are supported. For example, session based
   accounting is implicitly includes tenant context state correlation,
   as well as session based state which implicitly includes tenant
   context.

   Inter-domain Provisioning:

   Process:

   1) Cloud/DC orchestration system configures vCE.

   2) Cloud/DC orchestration system primes WAN IP VPN provisioning/AAA
   for new service, passes connection IDs (e.g., VLAN/VXLAN/NVGRE) and
   tenant context WAN IP VPN provisioning systems.

   3) Cloud/DC PE detects new VLAN, send Radius Access-Request.

   4) Radius Access-Accept with VRF and other policies.

   This model requires VLAN/VXLAN/NVGRE information and tenant context



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   to be passed on a per transaction basis. In practice, it may simplify
   to use DC orchestration updating LDAP directory.

   Auto accounting correlation and auto state correlation are supported
   in this model.

8. Security Considerations

   When vCE is created on a network or compute device, such as a server,
   the operator MUST evaluate the following conditions: Is server owned
   by the the operator? Is it using a managed CE model? How to
   authenticate? The ownership of the device where the vCE resides has
   major implication on the design, it determines where the boundary is
   between the trusted and un-trusted zones.

   When a vCE in DC connecting BGP MPLS IP VPN in the WAN, the amount of
   information can be exchanged across the two domains through auto-
   provisioning will be different depending on if the DC and WAN are
   under same administrative domain. Only limited and/or abstracted
   information should be exchanged if the two domains are owned by
   different SPs. Additional authentication, and other security
   mechanism need to be deployed to prevent accidental or malicious
   attach from the other domain.

   In addition, the connection authentication is very important for the
   pull models.

   And the virtual FW placement needs to be carefully designed to
   protect against attacks.

9. IANA Considerations

   None.

10. References

10.1  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC4271]  Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
              Border Gateway Protocol 4 (BGP-4)", RFC 4271, January
              2006.

   [RFC4364]  Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
              Networks (VPNs)", RFC 4364, February 2006.




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   [RFC4760]  Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
              "Multiprotocol Extensions for BGP-4", RFC 4760, January
              2007.

              [I-D.ietf-l3vpn-end-system] Marques, P., Fang, L., Pan,
              P., Shukla, A., Napierala, M., "BGP-signaled end-system
              IP/VPNs", draft-ietf-l3vpn-end-system, work in progress.

   [I-D.fang-l3vpn-virtual-pe] Fang, L., et al., "BGP IP VPN Virtual
              PE", draft-fang-l3vpn-virtual-pe, work in progress.

              [IEEE 802.1ad] IEEE, "Provider Bridges", 2005.

              [IEEE 802.1q] IEEE, "802.1Q - Virtual LANs", 2006.

              [IEEE 802.1ag] IEEE "802.1ag - Connectivity Fault
              Management", 2007.


10.2  Informative References

   [RFC2475]  Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
              and W. Weiss, "An Architecture for Differentiated
              Services", RFC 2475, December 1998.


   [I-D.ietf-i2rs-architecture] Atlas, A., Halpern, J., Hares, S., Ward,
              D., and T Nadeau, "An Architecture for the Interface to
              the Routing System", draft-ietf-i2rs-architecture, work in
              progress.

   [I-D.ietf-i2rs-problem-statement] Atlas, A., Nadeau, T., and Ward D.,
              "Interface to the Routing System Problem Statement",
              draft-ietf-i2rs-problem-statement, work in progress.

   [I-D.mahalingam-dutt-dcops-vxlan]: Mahalingam, M, Dutt, D., et al.,
              "A Framework for Overlaying Virtualized Layer 2 Networks
              over Layer 3 Networks" draft-mahalingam-dutt-dcops-vxlan,
              work in progress.

   [I-D.sridharan-virtualization-nvgre]: SridharanNetwork, M., et al.,
              "Virtualization using Generic Routing Encapsulation",
              draft-sridharan-virtualization-nvgre, work in progress.

11. Acknowledgement

   The authors would like to thank Vaughn Suazo for his review and
   comments.



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Authors' Addresses

   Luyuan Fang
   Cisco
   111 Wood Ave. South
   Iselin, NJ 08830
   Email: luyuanf@gmail.com

   John Evans
   Cisco
   16-18 Finsbury Circus
   London, EC2M 7EB, UK
   Email: joevans@cisco.com

   David Ward
   Cisco
   170 W Tasman Dr
   San Jose, CA 95134
   Email: wardd@cisco.com

   Rex Fernando
   Cisco
   170 W Tasman Dr
   San Jose, CA
   Email: rex@cisco.com

   John Mullooly
   Cisco
   111 Wood Ave. South
   Iselin, NJ 08830
   Email: jmullool@cisco.com

   Ning So
   Tata Communications
   Plano, TX 75082, USA
   Email: ning.so@tatacommunications.com

   Nabil Bitar
   Verizon
   40 Sylvan Road
   Waltham, MA 02145
   Email: nabil.bitar@verizon.com

   Maria Napierala
   AT&T
   200 Laurel Avenue
   Middletown, NJ 07748
   Email: mnapierala@att.com



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