NVO3 Working Group                                             Yizhou Li
INTERNET-DRAFT                                                 Lucy Yong
Intended Status: Informational                       Huawei Technologies
                                                        Lawrence Kreeger
                                                           Thomas Narten
                                                             David Black
Expires: September 1, 2017                             February 25, 28, 2017                               August 24, 2016

                  Split-NVE Control Plane Requirements


   In a Split-NVE architecture, the functions of the NVE are split
   across a server and an external network equipment which is called an
   external NVE.  The server-resident control plane functionality
   resides in control software, which may be part of a hypervisor or
   container management software; for simplicity, this draft refers to
   the hypervisor as the location of this software.

   A control plane protocol(s) between a hypervisor and its associated
   external NVE(s) is used for the hypervisor to distribute its virtual
   machine networking state to the external NVE(s) for further handling.
   This document illustrates the functionality required by this type of
   control plane signaling protocol and outlines the high level
   requirements. Virtual machine states as well as state transitioning
   are summarized to help clarifying the needed protocol requirements.

Status of this Memo

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   provisions of BCP 78 and BCP 79.

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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
     1.1  Terminology . . . . . . . . . . . . . . . . . . . . . . . .  5
     1.2  Target Scenarios  . . . . . . . . . . . . . . . . . . . . .  6
   2. VM Lifecycle  . . . . . . . . . . . . . . . . . . . . . . . . .  8
     2.1 VM Creation Event  . . . . . . . . . . . . . . . . . . . . .  8
     2.2 VM Live Migration Event  . . . . . . . . . . . . . . . . . .  9
     2.3 VM Termination Event . . . . . . . . . . . . . . . . . . . . 10
     2.4 VM Pause, Suspension and Resumption Events . . . . . . . . . 10
   3. Hypervisor-to-NVE Control Plane Protocol Functionality  . . . . 10
     3.1 VN connect and Disconnect  . . . . . . . . . . . . . . . . . 11
     3.2 TSI Associate and Activate . . . . . . . . . . . . . . . . . 12
     3.3 TSI Disassociate and Deactivate  . . . . . . . . . . . . . . 15
   4. Hypervisor-to-NVE Control Plane Protocol Requirements . . . . . 16
   5. VDP Applicability and Enhancement Needs . . . . . . . . . . . . 17
   6. Security Considerations . . . . . . . . . . . . . . . . . . . . 19
   7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 19
   8. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 19
   8. References  . . . . . . . . . . . . . . . . . . . . . . . . . . 20
     8.1  Normative References  . . . . . . . . . . . . . . . . . . . 20
     8.2  Informative References  . . . . . . . . . . . . . . . . . . 20

   Appendix A. IEEE 802.1Qbg VDP Illustration (For information
            only) . . . . . . . . . . . . . . . . . . . . . . . . . . 20
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 23

1.  Introduction

   In the Split-NVE architecture shown in Figure 1, the functionality of
   the NVE is split across an end device supporting virtualization and
   an external network device which is called an external NVE. The
   portion of the NVE functionality located on the end device is called
   the tNVE and the portion located on the external NVE is called the
   nNVE in this document. Overlay encapsulation/decapsulation functions
   are normally off-loaded to the nNVE on the external NVE.

   The tNVE is normally implemented as a part of hypervisor or container
   and/or virtual switch in an virtualized end device. This document
   uses the term "hypervisor" throughout when describing the Split-NVE
   scenario where part of the NVE functionality is off-loaded to a
   separate device from the "hypervisor" that contains a VM connected to
   a VN. In this context, the term "hypervisor" is meant to cover any
   device type where part of the NVE functionality is off-loaded in this
   fashion, e.g.,a Network Service Appliance, Linux Container.

   The problem statement [RFC7364], discusses the needs for a control
   plane protocol (or protocols) to populate each NVE with the state
   needed to perform the required functions. In one scenario, an NVE
   provides overlay encapsulation/decapsulation packet forwarding
   services to Tenant Systems (TSs) that are co-resident within the NVE
   on the same End Device (e.g. when the NVE is embedded within a
   hypervisor or a Network Service Appliance). In such cases, there is
   no need for a standardized protocol between the hypervisor and NVE,
   as the interaction is implemented via software on a single device.
   While in the Split-NVE architecture scenarios, as shown in figure 2
   to figure 4, a control plane protocol(s) between a hypervisor and its
   associated external NVE(s) is required for the hypervisor to
   distribute the virtual machines networking states to the NVE(s) for
   further handling. The protocol indeed is an NVE-internal protocol and
   runs between tNVE and nNVE logical entities. This protocol is
   mentioned in NVO3 problem statement [RFC7364] and appears as the
   third work item.

   Virtual machine states and state transitioning are summarized in this
   document to show events where the NVE needs to take specific actions.
   Such events might correspond to actions the control plane signaling
   protocols between the hypervisor and external NVE will need to take.
   Then the high level requirements to be fulfilled are outlined.

                     +-- --  -- -- Split-NVE -- -- -- --+
     | +------------- ----+|                            |
     | | +--+   +---\|/--+||                     +------ --------------+
     | | |VM|---+        |||                     |     \|/             |
     | | +--+   |        |||                     |+--------+           |
     | | +--+   |  tNVE  |||----- - - - - - -----||        |           |
     | | |VM|---+        |||                     || nNVE   |           |
     | | +--+   +--------+||                     ||        |           |
     | |                  ||                     |+--------+           |
     | +--Hypervisor------+|                     +---------------------+

            End Device                               External NVE

                        Figure 1 Split-NVE structure

   This document uses VMs as an example of Tenant Systems (TSs) in order
   to describe the requirements, even though a VM is just one type of
   Tenant System that may connect to a VN. For example, a service
   instance within a Network Service Appliance is another type of TS, as
   are systems running on an OS-level virtualization technologies like
   containers.  The fact that VMs have lifecycles(e.g., can be created
   and destroyed), can be moved, and can be started or stopped results
   in a general set of protocol requirements, most of which are
   applicable to other forms of TSs. It should also be noted that not
   all of the requirements are applicable to all forms of TSs.

   Section 2 describes VM states and state transitioning in its
   lifecycle. Section 3 introduces Hypervisor-to-NVE control plane
   protocol functionality derived from VM operations and network events.
   Section 4 outlines the requirements of the control plane protocol to
   achieve the required functionality.

1.1  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in RFC 2119 [RFC2119].

   This document uses the same terminology as found in [RFC7365] and [I-
   D.ietf-nvo3-nve-nva-cp-req]. This section defines additional
   terminology used by this document.

   Split-NVE: a type of NVE that the functionalities of it are split
   across an end device supporting virtualization and an external
   network device.

   tNVE: the portion of Split-NVE functionalities located on the end
   device supporting virtualization. It interacts with tenant system by
   internal interface in end device.

   nNVE: the portion of Split-NVE functionalities located on the network
   device which is directly or indirectly connects to the end device
   holding the corresponding tNVE. nNVE normally performs encapsulation
   and decapsulation to the overlay network.

   External NVE: the physical network device holding nNVE

   Hypervisor/Container: the logical collection of software, firmware
   and/or hardware that allows the creation and running of server or
   service appliance virtualization. tNVE is located on
   Hypervisor/Container. It is loosely used in this document to refer to
   the end device supporting the virtualization. For simplicity, we also
   use Hypervisor in this document to represent both hypervisor and

   VN Profile:  Meta data associated with a VN that is applied to any
   attachment point to the VN. That is, VAP properties that are appliaed
   to all VAPs associated with a given VN and used by an NVE when
   ingressing/egressing packets to/from a specific VN.  Meta data could
   include such information as ACLs, QoS settings, etc. The VN Profile
   contains parameters that apply to the VN as a whole.  Control
   protocols between the NVE and NVA could use the VN ID or VN Name to
   obtain the VN Profile.

   VSI: Virtual Station Interface. [IEEE 802.1Qbg]

   VDP: VSI Discovery and Configuration Protocol [IEEE 802.1Qbg]

1.2  Target Scenarios

   In the Split-NVE architecture, an external NVE can provide an offload
   of the encapsulation / decapsulation function, network policy
   enforcement, as well as the VN Overlay protocol overhead.  This
   offloading may provide performance improvements and/or resource
   savings to the End Device (e.g. hypervisor) making use of the
   external NVE.

   The following figures give example scenarios of a Split-NVE

              Hypervisor             Access Switch
         +------------------+       +-----+-------+
         | +--+   +-------+ |       |     |       |
         | |VM|---|       | | VLAN  |     |       |
         | +--+   | tNVE  |---------+ nNVE|       +--- Underlying
         | +--+   |       | | Trunk |     |       |    Network
         | |VM|---|       | |       |     |       |
         | +--+   +-------+ |       |     |       |
         +------------------+       +-----+-------+
               Figure 2 Hypervisor with an External NVE

              Hypervisor      L2 Switch
         +---------------+     +-----+     +----+---+
         | +--+   +----+ |     |     |     |    |   |
         | |VM|---|    | |VLAN |     |VLAN |    |   |
         | +--+   |tNVE|-------+     +-----+nNVE|   +--- Underlying
         | +--+   |    | |Trunk|     |Trunk|    |   | Network
         | |VM|---|    | |     |     |     |    |   |
         | +--+   +----+ |     |     |     |    |   |
         +---------------+     +-----+     +----+---+
          Figure 3 Hypervisor with an External NVE
                   across an Ethernet Access Switch

          Network Service Appliance         Access Switch
         +--------------------------+      +-----+-------+
         | +------------+    | \    |      |     |       |
         | |Net Service |----|  \   |      |     |       |
         | |Instance    |    |   \  | VLAN |     |       |
         | +------------+    |tNVE| |------+nNVE |       +--- Underlying
         | +------------+    |    | | Trunk|     |       |    Network
         | |Net Service |----|   /  |      |     |       |
         | |Instance    |    |  /   |      |     |       |
         | +------------+    | /    |      |     |       |
         +--------------------------+      +-----+-------+
       Figure 4 Physical Network Service Appliance with an External NVE

   Tenant Systems connect to external NVEs via a Tenant System Interface
   (TSI).  The TSI logically connects to the external NVE via a Virtual
   Access Point (VAP) [I-D.ietf-nvo3-arch]. The external NVE may provide
   Layer 2 or Layer 3 forwarding. In the Split-NVE architecture, the
   external NVE may be able to reach multiple MAC and IP addresses via a
   TSI. For example, Tenant Systems that are providing network services
   (such as transparent firewall, load balancer, VPN gateway) are likely
   to have complex address hierarchy. This implies that if a given TSI
   disassociates from one VN, all the MAC and/or IP addresses are also
   disassociated.  There is no need to signal the deletion of every MAC
   or IP when the TSI is brought down or deleted. In the majority of
   cases, a VM will be acting as a simple host that will have a single
   TSI and single MAC and IP visible to the external NVE.

   Figures 2-4 show the use of VLANs to separate traffic for multiple
   VNs between the tNVE and nNVE; VLANs are not strictly necessary if
   only one VN is involved, but multiple VNs are expected in most cases,
   and hence this draft assumes their presence.

2. VM Lifecycle

   Figure 2 of [I-D.ietf-opsawg-vmm-mib] shows the state transition of a
   VM. Some of the VM states are of interest to the external NVE. This
   section illustrates the relevant phases and events in the VM
   lifecycle. It should be noted that the following subsections do not
   give an exhaustive traversal of VM lifecycle state. They are intended
   as the illustrative examples which are relevant to Split-NVE
   architecture, not as prescriptive text; the goal is to capture
   sufficient detail to set a context for the signaling protocol
   functionality and requirements described in the following sections.

2.1 VM Creation Event

   VM creation event makes the VM state transiting from Preparing to
   Shutdown and then to Running [I-D.ietf-opsawg-vmm-mib]. The end
   device allocates and initializes local virtual resources like storage
   in the VM Preparing state. In Shutdown state, the VM has everything
   ready except that CPU execution is not scheduled by the hypervisor
   and VM's memory is not resident in the hypervisor. From the Shutdown
   state to Running state, normally it requires the human execution or
   system triggered event. Running state indicates the VM is in the
   normal execution state. As part of transitioning the VM to the
   Running state, the hypervisor must also provision network
   connectivity for the VM's TSI(s) so that Ethernet frames can be sent
   and received correctly. No ongoing migration, suspension or shutdown
   is in process.

   In the VM creation phase, the VM's TSI has to be associated with the
   external NVE. Association here indicates that hypervisor and the
   external NVE have signaled each other and reached some agreement.
   Relevant networking parameters or information have been provisioned
   properly. The External NVE should be informed of the VM's TSI MAC
   address and/or IP address. In addition to external network
   connectivity, the hypervisor may provide local network connectivity
   between the VM's TSI and other VM's TSI that are co-resident on the
   same hypervisor. When the intra or inter-hypervisor connectivity is
   extended to the external NVE, a locally significant tag, e.g. VLAN
   ID, should be used between the hypervisor and the external NVE to
   differentiate each VN's traffic. Both the hypervisor and external NVE
   sides must agree on that tag value for traffic identification,
   isolation and forwarding.

   The external NVE may need to do some preparation work before it
   signals successful association with TSI. Such preparation work may
   include locally saving the states and binding information of the
   tenant system interface and its VN, communicating with the NVA for
   network provisioning, etc.

   Tenant System interface association should be performed before the VM
   enters running state, preferably in Shutdown state. If association
   with external NVE fails, the VM should not go into running state.

2.2 VM Live Migration Event

   Live migration is sometimes referred to as "hot" migration, in that
   from an external viewpoint, the VM appears to continue to run while
   being migrated to another server (e.g., TCP connections generally
   survive this class of migration).  In contrast, "cold" migration
   consists of shutdown VM execution on one server and restart it on
   another. For simplicity, the following abstract summary about live
   migration assumes shared storage, so that the VM's storage is
   accessible to the source and destination servers. Assume VM live
   migrates from hypervisor 1 to hypervisor 2. Such migration event
   involves the state transition on both hypervisors, source hypervisor
   1 and destination hypervisor 2. VM state on source hypervisor 1
   transits from Running to Migrating and then to Shutdown [I-D.ietf-
   opsawg-vmm-mib]. VM state on destination hypervisor 2 transits from
   Shutdown to Migrating and then Running.

   The external NVE connected to destination hypervisor 2 has to
   associate the migrating VM's TSI with it by discovering the TSI's MAC
   and/or IP addresses, its VN, locally significant VID if any, and
   provisioning other network related parameters of the TSI. The
   external NVE may be informed about the VM's peer VMs, storage devices
   and other network appliances with which the VM needs to communicate
   or is communicating. The migrated VM on destination hypervisor 2
   SHOULD not go to Running state before all the network provisioning
   and binding has been done.

   The migrating VM SHOULD not be in Running state at the same time on
   the source hypervisor and destination hypervisor during migration.
   The VM on the source hypervisor does not transition into Shutdown
   state until the VM successfully enters the Running state on the
   destination hypervisor. It is possible that VM on the source
   hypervisor stays in Migrating state for a while after VM on the
   destination hypervisor is in Running state.

2.3 VM Termination Event

   VM termination event is also referred to as "powering off" a VM. VM
   termination event leads to its state going to Shutdown. There are two
   possible causes to terminate a VM [I-D.ietf-opsawg-vmm-mib], one is
   the normal "power off" of a running VM; the other is that VM has been
   migrated to another hypervisor and the VM image on the source
   hypervisor has to stop executing and to be shutdown.

   In VM termination, the external NVE connecting to that VM needs to
   deprovision the VM, i.e. delete the network parameters associated
   with that VM. In other words, the external NVE has to de-associate
   the VM's TSI.

2.4 VM Pause, Suspension and Resumption Events

   The VM pause event leads to the VM transiting from Running state to
   Paused state. The Paused state indicates that the VM is resident in
   memory but no longer scheduled to execute by the hypervisor [I-
   D.ietf-opsawg-vmm-mib]. The VM can be easily re-activated from Paused
   state to Running state.

   The VM suspension event leads to the VM transiting from Running state
   to Suspended state. The VM resumption event leads to the VM
   transiting state from Suspended state to Running state. Suspended
   state means the memory and CPU execution state of the virtual machine
   are saved to persistent store.  During this state, the virtual
   machine is not scheduled to execute by the hypervisor [I-D.ietf-

   In the Split-NVE architecture, the external NVE should keep any
   paused or suspended VM in association as the VM can return to Running
   state at any time.

3. Hypervisor-to-NVE Control Plane Protocol Functionality

   The following subsections show the illustrative examples of the state
   transitions on external NVE which are relevant to Hypervisor-to-NVE
   Signaling protocol functionality. It should be noted they are not
   prescriptive text for full state machines.

3.1 VN connect and Disconnect

   In Split-NVE scenario, a protocol is needed between the End
   Device(e.g. Hypervisor) making use of the external NVE and the
   external NVE in order to make the external NVE aware of the changing
   VN membership requirements of the Tenant Systems within the End

   A key driver for using a protocol rather than using static
   configuration of the external NVE is because the VN connectivity
   requirements can change frequently as VMs are brought up, moved and
   brought down on various hypervisors throughout the data center or
   external cloud.

       +---------------+   Recv VN_connect;        +-------------------+
       |VN_Disconnected|   return Local_Tag value  |VN_Connected       |
       +---------------+   for VN if successful;   +-------------------+
       |VN_ID;         |-------------------------->|VN_ID;             |
       |VN_State=      |                           |VN_State=connected;|
       |disconnected;  |                           |Num_TSI_Associated;|
       |               |<----Recv VN_disconnect----|Local_Tag;         |
       +---------------+                           |VN_Context;        |

            Figure 5 State Transition Example of a VAP Instance
                         on an External NVE

   Figure 5 shows the state transition for a VAP on the external NVE. An
   NVE that supports the hypervisor to NVE control plane protocol should
   support one instance of the state machine for each active VN. The
   state transition on the external NVE is normally triggered by the
   hypervisor-facing side events and behaviors. Some of the interleaved
   interaction between NVE and NVA will be illustrated for better
   understanding of the whole procedure; while others of them may not be
   shown. More detailed information regarding that is available in [I-

   The external NVE must be notified when an End Device requires
   connection to a particular VN and when it no longer requires
   connection. In addition, the external NVE must provide a local tag
   value for each connected VN to the End Device to use for exchange of
   packets between the End Device and the external NVE (e.g. a locally
   significant 802.1Q tag value). How "local" the significance is
   depends on whether the Hypervisor has a direct physical connection to
   the external NVE (in which case the significance is local to the
   physical link), or whether there is an Ethernet switch (e.g. a blade
   switch) connecting the Hypervisor to the NVE (in which case the
   significance is local to the intervening switch and all the links
   connected to it).

   These VLAN tags are used to differentiate between different VNs as
   packets cross the shared access network to the external NVE. When the
   external NVE receives packets, it uses the VLAN tag to identify the
   VN of packets coming from a given TSI, strips the tag, and adds the
   appropriate overlay encapsulation for that VN and sends it towards
   the corresponding remote NVE across the underlying IP network.

   The Identification of the VN in this protocol could either be through
   a VN Name or a VN ID. A globally unique VN Name facilitates
   portability of a Tenant's Virtual Data Center. Once an external NVE
   receives a VN connect indication, the NVE needs a way to get a VN
   Context allocated (or receive the already allocated VN Context) for a
   given VN Name or ID (as well as any other information needed to
   transmit encapsulated packets).  How this is done is the subject of
   the NVE-to-NVA protocol which are part of work items 1 and 2 in

   VN_connect message can be explicit or implicit. Explicit means the
   hypervisor sending a message explicitly to request for the connection
   to a VN. Implicit means the external NVE receives other messages,
   e.g. very first TSI associate message (see the next subsection) for a
   given VN, to implicitly indicate its interest to connect to a VN.

   A VN_disconnect message will indicate that the NVE can release all
   the resources for that disconnected VN and transit to VN_disconnected
   state. The local tag assigned for that VN can possibly be reclaimed
   by other VN.

3.2 TSI Associate and Activate

   Typically, a TSI is assigned a single MAC address and all frames
   transmitted and received on that TSI use that single MAC address. As
   mentioned earlier, it is also possible for a Tenant System to
   exchange frames using multiple MAC addresses or packets with multiple
   IP addresses.

   Particularly in the case of a TS that is forwarding frames or packets
   from other TSs, the external NVE will need to communicate the mapping
   between the NVE's IP address (on the underlying network) and ALL the
   addresses the TS is forwarding on behalf of for the corresponding VN
   to the NVA.

   The NVE has two ways in which it can discover the tenant addresses
   for which frames must be forwarded to a given End Device (and
   ultimately to the TS within that End Device).

   1.  It can glean the addresses by inspecting the source addresses in
   packets it receives from the End Device.

   2.  The hypervisor can explicitly signal the address associations of
   a TSI to the external NVE. The address association includes all the
   MAC and/or IP addresses possibly used as source addresses in a packet
   sent from the hypervisor to external NVE. The external NVE may
   further use this information to filter the future traffic from the

   To perform the second approach above, the "hypervisor-to-NVE"
   protocol requires a means to allow End Devices to communicate new
   tenant addresses associations for a given TSI within a given VN.

   Figure 6 shows the example of a state transition for a TSI connecting
   to a VAP on the external NVE. An NVE that supports the hypervisor to
   NVE control plane protocol may support one instance of the state
   machine for each TSI connecting to a given VN.

                 disassociate;  +--------+     disassociate
               +--------------->|  Init  |<--------------------+
               |                +--------+                     |
               |                |        |                     |
               |                |        |                     |
               |                +--------+                     |
               |                  |    |                       |
               |       associate  |    |  activate             |
               |      +-----------+    +-----------+           |
               |      |                            |           |
               |      |                            |           |
               |     \|/                          \|/          |
       +--------------------+                  +---------------------+
       |     Associated     |                  |       Activated     |
       +--------------------+                  +---------------------+
       |TSI_ID;             |                  |TSI_ID;              |
       |Port;               |-----activate---->|Port;                |
       |VN_ID;              |                  |VN_ID;               |
       |State=associated;   |                  |State=activated ;    |-+
     +-|Num_Of_Addr;        |<---deactivate;---|Num_Of_Addr;         | |
     | |List_Of_Addr;       |                  |List_Of_Addr;        | |
     | +--------------------+                  +---------------------+ |
     |                    /|\                     /|\                  |
     |                     |                       |                   |
     +---------------------+                       +-------------------+
      add/remove/updt addr;                        add/remove/updt addr;
      or update port;                              or update port;

              Figure 6 State Transition Example of a TSI Instance
                             on an External NVE

   Associated state of a TSI instance on an external NVE indicates all
   the addresses for that TSI have already associated with the VAP of
   the external NVE on port p for a given VN but no real traffic to and
   from the TSI is expected and allowed to pass through. An NVE has
   reserved all the necessary resources for that TSI. An external NVE
   may report the mappings of its' underlay IP address and the
   associated TSI addresses to NVA and relevant network nodes may save
   such information to its mapping table but not forwarding table. A NVE
   may create ACL or filter rules based on the associated TSI addresses
   on the attached port p but not enable them yet. Local tag for the VN
   corresponding to the TSI instance should be provisioned on port p to
   receive packets.

   VM migration event(discussed section 2) may cause the hypervisor to
   send an associate message to the NVE connected to the destination
   hypervisor the VM migrates to. VM creation event may also lead to the
   same practice.

   The Activated state of a TSI instance on an external NVE indicates
   that all the addresses for that TSI functioning correctly on port p
   and traffic can be received from and sent to that TSI via the NVE.
   The mappings of the NVE's underlay IP address and the associated TSI
   addresses should be put into the forwarding table rather than the
   mapping table on relevant network nodes. ACL or filter rules based on
   the associated TSI addresses on the attached port p in NVE are
   enabled. Local tag for the VN corresponding to the TSI instance MUST
   be provisioned on port p to receive packets.

   The Activate message makes the state transit from Init or Associated
   to Activated. VM creation, VM migration and VM resumption events
   discussed in section 4 may trigger the Activate message to be sent
   from the hypervisor to the external NVE.

   TSI information may get updated either in Associated or Activated
   state. The following are considered updates to the TSI information:
   add or remove the associated addresses, update current associated
   addresses (for example updating IP for a given MAC), update NVE port
   information based on where the NVE receives messages. Such updates do
   not change the state of TSI. When any address associated to a given
   TSI changes, the NVE should inform the NVA to update the mapping
   information on NVE's underlying address and the associated TSI
   addresses. The NVE should also change its local ACL or filter
   settings accordingly for the relevant addresses. Port information
   update will cause the local tag for the VN corresponding to the TSI
   instance to be provisioned on new port p and removed from the old

3.3 TSI Disassociate and Deactivate

   Disassociate and deactivate conceptually are the reverse behaviors of
   associate and activate. From Activated state to Associated state, the
   external NVE needs to make sure the resources are still reserved but
   the addresses associated to the TSI are not functioning and no
   traffic to and from the TSI is expected and allowed to pass through.
   For example, the NVE needs to inform the NVA to remove the relevant
   addresses mapping information from forwarding or routing table. ACL
   or filtering rules regarding the relevant addresses should be
   disabled. From Associated or Activated state to the Init state, the
   NVE will release all the resources relevant to TSI instances. The NVE
   should also inform the NVA to remove the relevant entries from
   mapping table. ACL or filtering rules regarding the relevant
   addresses should be removed. Local tag provisioning on the connecting
   port on NVE should be cleared.

   A VM suspension event(discussed in section 2) may cause the relevant
   TSI instance(s) on the NVE to transit from Activated to Associated
   state. A VM pause event normally does not affect the state of the
   relevant TSI instance(s) on the NVE as the VM is expected to run
   again soon. The VM shutdown event will normally cause the relevant
   TSI instance(s) on NVE transit to Init state from Activated state.
   All resources should be released.

   A VM migration will lead the TSI instance on the source NVE to leave
   Activated state. When a VM migrates to another hypervisor connecting
   to the same NVE, i.e. source and destination NVE are the same, NVE
   should use TSI_ID and incoming port to differentiate two TSI

   Although the triggering messages for state transition shown in Figure
   6 does not indicate the difference between VM creation/shutdown event
   and VM migration arrival/departure event, the external NVE can make
   optimizations if it is notified of such information. For example, if
   the NVE knows the incoming activate message is caused by migration
   rather than VM creation, some mechanisms may be employed or triggered
   to make sure the dynamic configurations or provisionings on the
   destination NVE are the same as those on the source NVE for the
   migrated VM. For example IGMP query [RFC2236] can be triggered by the
   destination external NVE to the migrated VM on destination hypervisor
   so that the VM is forced to answer an IGMP report to the multicast
   router. Then multicast router can correctly send the multicast
   traffic to the new external NVE for those multicast groups the VM had
   joined before the migration.

4. Hypervisor-to-NVE Control Plane Protocol Requirements

   Req-1: The protocol MUST support a bridged network connecting End
   Devices to External NVE.

   Req-2: The protocol MUST support multiple End Devices sharing the
   same External NVE via the same physical port across a bridged

   Req-3: The protocol MAY support an End Device using multiple external
   NVEs simultaneously, but only one external NVE for each VN.

   Req-4: The protocol MAY support an End Device using multiple external
   NVEs simultaneously for the same VN.

   Req-5: The protocol MUST allow the End Device initiating a request to
   its associated External NVE to be connected/disconnected to a given

   Req-6: The protocol MUST allow an External NVE initiating a request
   to its connected End Devices to be disconnected to a given VN.

   Req-7: When a TS attaches to a VN, the protocol MUST allow for an End
   Device and its external NVE to negotiate one or more locally-
   significant tag(s) for carrying traffic associated with a specific VN
   (e.g., 802.1Q tags).

   Req-8: The protocol MUST allow an End Device initiating a request to
   associate/disassociate and/or activate/deactive address(es) of a TSI
   instance to a VN on an NVE port.

   Req-9: The protocol MUST allow the External NVE initiating a request
   to disassociate and/or deactivate address(es) of a TSI instance to a
   VN on an NVE port.

   Req-10: The protocol MUST allow an End Device initiating a request to
   add, remove or update address(es) associated with a TSI instance on
   the external NVE. Addresses can be expressed in different formats,
   for example, MAC, IP or pair of IP and MAC.

   Req-11: The protocol MUST allow the External NVE to authenticate the
   End Device connected.

   Req-12: The protocol MUST be able to run over L2 links between the
   End Device and its External NVE.

   Req-13: The protocol SHOULD support the End Device indicating if an
   associate or activate request from it results from a VM hot migration

5. VDP Applicability and Enhancement Needs

   Virtual Station Interface (VSI) Discovery and Configuration Protocol
   (VDP) [IEEE 802.1Qbg] can be the control plane protocol running
   between the hypervisor and the external NVE. Appendix A illustrates
   VDP for reader's information.

   VDP facilitates the automatic discovery and configuration for Edge
   Virtual Bridging (EVB) station and Edge Virtual Bridging (EVB)
   bridge. EVB station is normally an end station running multiple VMs.
   It is conceptually equivalent to hypervisor in this document. And EVB
   bridge is conceptually equivalent to the external NVE.

   VDP is able to pre-associate/associate/de-associate a VSI on EVB
   station to a port on the EVB bridge. VSI is approximately the concept
   of a virtual port a VM connects to the hypervisor in this document
   context. The EVB station and the EVB bridge can reach the agreement
   on VLAN ID(s) assigned to a VSI via VDP message exchange. Other
   configuration parameters can be exchanged via VDP as well. VDP is
   carried over Edge Control Protocol(ECP) [IEEE8021Qbg] which provides
   a reliable transportation over a layer 2 network.

   VDP protocol needs some extensions to fulfill the requirements listed
   in this document. Table 1 shows the needed extensions and/or
   clarifications in NVO3 context.

   | Req  | VDP       |   remarks                                     |
   |      | supported?|                                               |
   | Req-1|           |                                               |
   +------+           |Needs extension. Must be able to send to a     |
   | Req-2|           |specific unicast MAC and should be able to send|
   +------+ Partially |to a non-reserved well known multicast address |
   | Req-3|           |other than the nearest customer bridge address |
   +------+           |                                               |
   | Req-4|           |                                               |
   | Req-5| Yes       |VN is indicated by GroupID                     |
   | Req-6| Yes       |Bridge sends De-Associate                      |
   |      |           |VID==NULL in request and bridge returns the    |
   | Req-7| Yes       |assigned value in response or specify GroupID  |
   |      |           |in request and get VID assigned in returning   |
   |      |           |response. Multiple VLANs per group is allowed  |
   |      |           |  requirements          |  VDP equivalence     |
   |      |           +------------------------+----------------------+
   |      |           |  associate/disassociate|pre-asso/de-associate |
   | Req-8| Partially |  activate/deactivate   |associate/de-associate|
   |      |           +------------------------+----------------------|
   |      |           |Needs extension to allow associate->pre-assoc  |
   | Req-9| Yes       | VDP bridge initiates de-associate             |
   |Req-10| Partially |Needs extension for IPv4/IPv6 address. Add a   |
   |      |           |new "filter info format" type                  |
   |Req-11| No        |Out-of-band mechanism is preferred, e.g. MACSec|
   |      |           |or 802.1x.                                     |
   |Req-12| Yes       |L2 protocol naturally                          |
   |      |           |M bit for migrated VM on destination hypervisor|
   |      |           |and S bit for that on source hypervisor.       |
   |Req-13| Partially |It is indistinguishable when M/S is 0 between  |
   |      |           |no guidance and events not caused by migration |
   |      |           |where NVE may act differently. Needs new       |
   |      |           |New bits for migration indication in new       |
   |      |           |"filter info format" type                      |
                 Table 1 Compare VDP with the requirements

   Simply adding the ability to carry layer 3 addresses, VDP can serve
   the Hypervisor-to-NVE control plane functions pretty well. Other
   extensions are the improvement of the protocol capabilities for
   better fit in NVO3 network.

6. Security Considerations

   NVEs must ensure that only properly authorized Tenant Systems are
   allowed to join and become a part of any specific Virtual Network. In
   addition, NVEs will need appropriate mechanisms to ensure that any
   hypervisor wishing to use the services of an NVE are properly
   authorized to do so. One design point is whether the hypervisor
   should supply the NVE with necessary information (e.g., VM addresses,
   VN information, or other parameters) that the NVE uses directly, or
   whether the hypervisor should only supply a VN ID and an identifier
   for the associated VM (e.g., its MAC address), with the NVE using
   that information to obtain the information needed to validate the
   hypervisor-provided parameters or obtain related parameters in a
   secure manner.

7. IANA Considerations

   No IANA action is required. RFC Editor: please delete this section
   before publication.

8. Acknowledgements

   This document was initiated and merged from the drafts draft-kreeger-
   nvo3-hypervisor-nve-cp, draft-gu-nvo3-tes-nve-mechanism and draft-
   kompella-nvo3-server2nve. Thanks to all the co-authors and
   contributing members of those drafts.

   The authors would like to specially thank Jon Hudson for his generous
   help in improving the readability of this document.

8. References

8.1  Normative References

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

8.2  Informative References

   [RFC7364] Narten, T., Gray, E., Black, D., Fang, L., Kreeger, L., and
              M. Napierala, "Problem Statement: Overlays for Network
              Virtualization", October 2014.

   [RFC7365] Lasserre, M., Balus, F., Morin, T., Bitar, N., and Y.
              Rekhter, "Framework for DC Network Virtualization",
              October 2014.

   [I-D.ietf-nvo3-nve-nva-cp-req] Kreeger, L., Dutt, D., Narten, T., and
              D. Black, "Network Virtualization NVE to NVA Control
              Protocol Requirements", draft-ietf-nvo3-nve-nva-cp-req-01
              (work in progress), October 2013.

   [I-D.ietf-nvo3-arch] Black, D., Narten, T., et al, "An Architecture
              for Overlay Networks (NVO3)", draft-narten-nvo3-arch, work
              in progress.

   [I-D.ietf-opsawg-vmm-mib] Asai H., MacFaden M., Schoenwaelder J.,
              Shima K., Tsou T., "Management Information Base for
              Virtual Machines Controlled by a Hypervisor", draft-ietf-
              opsawg-vmm-mib-00 (work in progress), February 2014.

   [IEEE 802.1Qbg] IEEE, "Media Access Control (MAC) Bridges and Virtual
              Bridged Local Area Networks - Amendment 21: Edge Virtual
              Bridging", IEEE Std 802.1Qbg, 2012

   [8021Q] IEEE, "Media Access Control (MAC) Bridges and Virtual Bridged
              Local Area Networks", IEEE Std 802.1Q-2011, August, 2011

Appendix A. IEEE 802.1Qbg VDP Illustration (For information only)

VDP has the format shown in Figure A.1. Virtual Station Interface (VSI)
is an interface to a virtual station that is attached to a downlink port
of an internal bridging function in server. VSI's VDP packet will be
handled by an external bridge. VDP is the controlling protocol running
between the hypervisor and the external bridge.

|TLV type|TLV info|Status|VSI |VSI |VSIID | VSIID|Filter|Filter Info|
| 7b     |str len |      |Type|Type|Format|      | Info |           |
|        |  9b    | 1oct |ID  |Ver |      |      |format|           |
|        |        |      |3oct|1oct| 1oct |16oct |1oct  | M oct     |
|                 |      |                       |                  |
|                 |      |<--VSI type&instance-->|<----Filter------>|
|                 |      |<------------VSI attributes-------------->|
|<--TLV header--->|<-------TLV info string = 23 + M octets--------->|

                       Figure A.1: VDP TLV definitions

There are basically four TLV types.

1. Pre-Associate: Pre-Associate is used to pre-associate a VSI instance
with a bridge port.  The bridge validates the request and returns a
failure Status in case of errors.  Successful pre-association does not
imply that the indicated VSI Type or provisioning will be applied to any
traffic flowing through the VSI. The pre-associate enables faster
response to an associate, by allowing the bridge to obtain the VSI Type
prior to an association.

2. Pre-Associate with resource reservation: Pre-Associate with Resource
Reservation involves the same steps as Pre-Associate, but on successful
pre-association also reserves resources in the Bridge to prepare for a
subsequent Associate request.

3. Associate: The Associate creates and activates an association between
a VSI instance and a bridge port. The Bridge allocates any required
bridge resources for the referenced VSI. The Bridge activates the
configuration for the VSI Type ID. This association is then applied to
the traffic flow to/from the VSI instance.

4. Deassociate: The de-associate is used to remove an association
between a VSI instance and a bridge port. Pre-Associated and Associated
VSIs can be de-associated. De-associate releases any resources that were
reserved as a result of prior Associate or Pre-Associate operations for
that VSI instance.

Deassociate can be initiated by either side and the rest types of
messages can only be initiated by the server side.

Some important flag values in VDP Status field:

1. M-bit (Bit 5): Indicates that the user of the VSI (e.g., the VM) is
migrating (M-bit = 1) or provides no guidance on the migration of the
user of the VSI (M-bit = 0).  The M-bit is used as an indicator relative
to the VSI that the user is migrating to.

2. S-bit (Bit 6): Indicates that the VSI user (e.g., the VM) is
suspended (S-bit = 1) or provides no guidance as to whether the user of
the VSI is suspended (S-bit = 0).  A keep-alive Associate request with
S-bit = 1 can be sent when the VSI user is suspended. The S-bit is used
as an indicator relative to the VSI that the user is migrating from.

The filter information format currently supports 4 types as the

1. VID Filter Info format
   | #of     | PS   | PCP   | VID    |
   |entries  |(1bit)|(3bits)|(12bits)|
   |(2octets)|      |       |        |
             |<--Repeated per entry->|

      Figure A.2 VID Filter Info format

2. MAC/VID filter format
   | #of     |  MAC address | PS   | PCP   | VID    |
   |entries  |  (6 octets)  |(1bit)|(3bits)|(12bits)|
   |(2octets)|              |      |       |        |
             |<--------Repeated per entry---------->|

      Figure A.3 MAC/VID filter format

3. GroupID/VID filter format
   | #of     |  GroupID     | PS   | PCP   | VID    |
   |entries  |  (4 octets)  |(1bit)|(3bits)|(12bits)|
   |(2octets)|              |      |       |        |
             |<--------Repeated per entry---------->|

      Figure A.4 GroupID/VID filter format

4. GroupID/MAC/VID filter format
| #of     | GroupID  | MAC address | PS   | PCP | VID    |
|entries  |(4 octets)| (6 octets)  |(1bit)|(3b )|(12bits)|
|(2octets)|          |             |      |     |        |
          |<-------------Repeated per entry------------->|
      Figure A.5 GroupID/MAC/VID filter format

The null VID can be used in the VDP Request sent from the hypervisor to
the external bridge. Use of the null VID indicates that the set of VID
values associated with the VSI is expected to be supplied by the Bridge.
The Bridge can obtain VID values from the VSI Type whose identity is
specified by the VSI Type information in the VDP Request. The set of VID
values is returned to the station via the VDP Response. The returned VID
value can be a locally significant value. When GroupID is used, it is
equivalent to the VN ID in NVO3. GroupID will be provided by the
hypervisor to the bridge. The bridge will map GroupID to a locally
significant VLAN ID.

The VSIID in VDP request that identify a VM can be one of the following
format: IPV4 address, IPV6 address, MAC address, UUID or locally

Authors' Addresses

   Yizhou Li
   Huawei Technologies
   101 Software Avenue,
   Nanjing 210012

   Phone: +86-25-56625409
   EMail: liyizhou@huawei.com

   Lucy Yong
   Huawei Technologies, USA

   Email: lucy.yong@huawei.com

   Lawrence Kreeger

   Email: kreeger@cisco.com
   Thomas Narten

   Email: narten@us.ibm.com
   David Black

   Email: david.black@emc.com