Network Virtualization Overlays Working Q. Wu Group Huawei Internet-Draft April 15, 2013 Intended status: Standards Track Expires: October 17, 2013 Signaling control/forward plane information between network virtualization edges (NVEs) draft-wu-nvo3-nve2nve-03 Abstract This document focuses on control plane aspect related to both tenant system to NVE control interface and NVE to Oracle control interface NVE use to enable communication between tenant systems, which is complementary to [draft-kreeger-nvo3-hypervisor-nve-cp] that describes the high level control plane requirements related to the interaction between tenant system and NVE when the two entities are not co-located on the same physical device. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." This Internet-Draft will expire on October 17, 2013. Copyright 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 Wu Expires October 17, 2013 [Page 1] Internet-Draft NVE2NVE April 2013 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 . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions used in this document . . . . . . . . . . . . . . 4 3. NVO3 Control plane Overview . . . . . . . . . . . . . . . . . 5 4. Mapping table entry at the NVE and Network Virtualization Authority . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4.1. Mapping table Entry Fields relationship . . . . . . . . . 8 4.2. Multihoming support using one TS or vNIC . . . . . . . . . 10 4.3. Interconnection functionality . . . . . . . . . . . . . . 10 5. NVE to Oracle Control plane protocol functionality . . . . . . 13 5.1. NVE connect/disconnect notification . . . . . . . . . . . 13 5.2. VN membership Registration and Query . . . . . . . . . . . 13 5.3. Address Mapping information reflection/distribution . . . 14 5.4. VN context moving . . . . . . . . . . . . . . . . . . . . 14 6. Hypervisor-to-NVE Control Plane Protocol Functionality . . . . 15 6.1. Multiple addresses association of one TS . . . . . . . . . 15 7. Key functions aspect for signaling control/forwarding info to NVEs . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 7.1. Create and Update tenant Virtual Network (VN) . . . . . . 16 7.2. Associate the NVE and tenant system with VN context . . . 16 7.3. Populate mapping tables information at the local NVE . . . 17 7.4. Distribute the mapping table information to remote NVEs in the VN . . . . . . . . . . . . . . . . . . . . . . 17 7.5. The mapping table information update at the NVE when VM moves or connection fails . . . . . . . . . . . . . . . 17 7.6. The VN context re-association at the NVE when VM moves . . 18 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 9. Security Considerations . . . . . . . . . . . . . . . . . . . 20 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 21 10.1. Normative References . . . . . . . . . . . . . . . . . . . 21 10.2. Informative References . . . . . . . . . . . . . . . . . . 21 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 22 Wu Expires October 17, 2013 [Page 2] Internet-Draft NVE2NVE April 2013 1. Introduction In [I.D-ietf-nvo3-overlay-problem-statement], two control planes are identified to realize an overlay solution: o NVE to Oracle control plane. o Tenant system to NVE control plane. Where NVE to Oracle Control plane is used to deal with address mapping dissemination and Tenant System to NVE control plane is used to deal with VM attachment and detachment. In [I.D-ietf-nvo3-framework], three control plane components are defined to build these two control planes and provide the following capabilities: o Auto-provision/service discovery o Address advertisement o Tunnel Managment In [I.D-fw-nvo3-server2vcenter],the control interface between NVE and the Oracle backend system or Network Virtualization Authority (NVA) is defined to provide the capability: o Enforce the network policy for each VM in the path from the NVE Edge associated with VM to the Tenant End System. o Populate forwarding table in the path from the NVE Edge associated with VM to the Tenant End System in the data center. o Populate mapping table in each NVE Edge that is in the virtual network across data centers under the control of the Director. This document focuses on control plane aspect related to both tenant system to NVE control interface and NVE to Oracle control interface NVE use to enable communication between tenant systems, which is complementary to [draft-kreeger-nvo3-hypervisor-nve-cp] that describes the high level control plane requirements related to the interaction between tenant system and NVE when the two entities are not co-located on the same physical device. Wu Expires October 17, 2013 [Page 3] Internet-Draft NVE2NVE April 2013 2. Conventions used in this document 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 RFC2119 [RFC2119]. Site : If multiple tenant systems connect to the VN through one NVE, the collection of these tenant systems and the NVE associated with these tenant systems are referred to as a site or virtualization network subnet. Tenant System: A physical or virtual system that can play the role of a host, or a forwarding element such as a router, switch, firewall, etc. It belongs to a single tenant and connects to one or more VNs of that tenant. vNIC: A vNIC is similar to a physical NIC. Each virtual machine has one or more vNIC adapters that it uses to communicate with both the virtual and physical networks. Each vNIC has its own MAC address and can be assigned one or more IP address just like a NIC found in a non virtualized machine. Wu Expires October 17, 2013 [Page 4] Internet-Draft NVE2NVE April 2013 3. NVO3 Control plane Overview Figure 1 shows the example NVO3 Networking architecture to give an overview of NVO3 control plane for interconnection between VNs or between VN and Non-VN. There are 4 basic network components that make up networking architecture: Tenant system, local NVE, remote NVE and Network Virtualization Authority. This example NVO3 networking architecture assumes that: o Each server or server blade that is running hypervisor hosts multiple virtual machines. o Each tenant system is corresponding to one virtual machine vNIC. Each virtual machine has one or more vNIC adapters that it uses to communicate with both the virtual and physical networks.The vNIC adapters each virtual machine has belong to a single tenant. o One tenant system or a NVE may belong to one tenant VN or several tenant VNs, e.g., TS4 and NVE Edge4 belong to both VN2 and VN3. o If one tenant system belongs to multiple tenant VNs, it may have one VM with multiple vNICs and connect to each tenant VN by using each of vNICs being attached to one or multiple NVEs,e.g., VM1 connect to VN1 by being attached to NVE Edge 1. o If one tenant system belongs to multiple tenant VNs, it may have multiple VM with each having one vNIC and connect to each tenant VN by using each VM vNIC being attached to one or multiple NVEs. o One NVE only belongs to one site. One site may belong to one tenant VN or several tenant VN, e.g., Site 2 belong to both VN2 and VN3. o If one tenant system in one VN want to communicate with one tenant system in another VN, the interconnection functionality or Network Virtualization Authority or Network Virtualization controller may get involved to help establish interconnection between VN or setup tunnel between NVEs associated with the tenant system. Wu Expires October 17, 2013 [Page 5] Internet-Draft NVE2NVE April 2013 +---------------+-------------+--------------+ | VN1 | +--------+ | +--------+ | | | |VM1VM2VM3 | |VM4VM5VM6 | | | +--------+ | +--------+ | | | | | | | | | | | |Server1 | | |Server2 | | | | | | | | | | | | +--------+ | +--------+ | | | +---------+ | +---------+| | -+-|NVE Edge1+-+---+NVE Edge2++- | // | +---------+ | +---------+| \\ | | |Site1 | | | | | +-------------+ +VN3--------+---+------------+ | |--+---+ +---+ | |+---+ +---|--+ | | |VMd S | | | | || | | S |VMh | | | | e | |NVE| | ||NVE| | e | | | | | | r | | | | || | | r | | | | |VMe v | | E | ,---------. | || E | | v |VMi | | | | e | | d | Interconnection | || d | | e | | | | | | r | | g |( )| || g | | r | | | | |VMf | | e | `Functionality' | || e | | |VMj | | | | 5 | | 5 | `---------' | || 6 | | 6 | | | | |VMg | | | | || | | |VMk | | |--|---+ ++--+ | |++--+ |---+--+ | +-----------+--------------------+-----------+ | | | | | | | +VN2--------------+------------+ | | . |... .............|Site2..... .| | | .| | +---------+ .. |+---------+ |// | . \\| |NVE Edge3+-----++NVE Edge4+-+ | . | +---------+ |+---------+ | | . | +--------+ .. | +--------+ | . | . | | | .. | | | | . | . | |Server3 | .. | |Server4 | | . | . | | | .. | | | | . | . | +--------+ .. | +--------+ | . | . | |VM7VM8VM9 .. | |VMaVMbVMc | . | ....| ---------+......|.---------+ |.. | +-----------------+------------+ | +----------------------------+ Figure 1: Example NVO3 control plane Overview Wu Expires October 17, 2013 [Page 6] Internet-Draft NVE2NVE April 2013 4. Mapping table entry at the NVE and Network Virtualization Authority Suppose a VM has multiple vNICs, each VM vNIC is corresponding to a tenant system. Tenant system should be able to directly connect to multiple VNs without needing to traverse a NVE or gateway. Therefore every NVE pair( local NVE and remote NVE ) associated with the tenant system MUST maintain at least one mapping table entry for each currently attached tenant system (In TS multihoming case, there may have multiple mapping table entry corresponding to one TS). Each mapping table entry corresponds to the Tenant system connection to each VN and conceptually may contain all or a sub set of the following fields: o The tunnel interface identifier (tunnel-if-id) of the tunnel between the remote NVE and the local NVE where the tenant system is currently attached. The tunnel interface identifier is acquired during the tunnel creation. o The MAC address of the attached TS. This MAC address is obtained from auto-discovery protocol between Tenant System and its local NVE. o The IP address of the attached TS. This IP address is obtained from auto-discovery protocol between Tenant System and its local NVE. o The logical interface identifier (e.g., VLAN ID, internal vSwitch Interface ID connected to a Tenant System) of the access link between the tenant system and the local NVE. This field is required to associate Tenant System with local NVE if local NVE is an external NVE to Tenant system. It is internal to the local NVE and is also used to associate the tunnel to the access link where the tenant system is attached. o The MAC address of the local NVE associated with the tenant system. o The IP address of the local NVE associated with the tenant system. o The Identifier of VN context-VNID. This Identifier is obtained from auto-discovery protocol between Tenant System and its local NVE. In addition, the Network Virtualization Authority or Oracle backend system may also maintain a mapping table entry for each currently attached tenant systemor each newly joined NVE. Each mapping table entry corresponds to the Tenant system connection to each VN and and conceptually may contain all or a sub set of the following fields: Wu Expires October 17, 2013 [Page 7] Internet-Draft NVE2NVE April 2013 o The MAC address of the attached TS. This MAC address is obtained from auto-discovery protocol between Tenant System and its local NVE.(Optional) o The IP address of the attached TS. This IP address is obtained from auto-discovery protocol between Tenant System and its local NVE. (Optional) o The logical interface identifier (e.g., VLAN ID, internal vSwitch Interface ID connected to a Tenant System) of the access link between the tenant system and the local NVE. This field is required to associate with Tenant System if local NVE is an external NVE to Tenant system. It is internal to the local NVE and is also used to associate the tunnel to the access link where the tenant system is attached. o The MAC address of the local NVE associated with the tenant system. o The IP address of the local NVE associated with the tenant system. o The Identifier of VN context-VNID. This Identifier is obtained from auto-discovery protocol between Tenant System and its local NVE. 4.1. Mapping table Entry Fields relationship One Tenant system is corresponding to one VM vNIC. Each VM belongs to a single tenant. Each VM may have one or more vNIC adapters that it uses to communicate with both the virtual and physical networks. Each vNIC must have one and only one unique MAC address. In addition, each vNIC have at least one IP address. When a VM using one vNIC connects to multiple VNs,the vNIC should be assigned with multiple IP addresses with each connecting to different VN. In this case, VM may create multiple binding cache entries with each associating one of multiple IP addresses to the same unique vNIC MAC address. vNIC MAC address may be modified or assigned with a new MAC address at any time. However vNIC should not use more than one MAC addresses to connect to multiple VNs at the same time. When multiple vNICs hosted in the same VM connect to multiple VNs, it is allowed that some of these vNICs may connect to different VNs through the same NVE. A Server running hypervisor | +--------------+--------------+ | | | | | Wu Expires October 17, 2013 [Page 8] Internet-Draft NVE2NVE April 2013 VM1 VM2 ..... VMx | | | |---------+--------+ vNIC vNIC | | | | | | vNIC1 vNIC2 ... vNICx | | +------+------+ | | | VN1 VN2 ...VNx Figure 2. VM information Hierarchy VM1(Tenant Systems) | |---------+--------+ | | | | | | vNIC1(TS1) vNIC2(TS2) ..vNICx(TSx) | | | NVE | +-------+------+ | | | VN1 VN2 VN3 Binding Cache Database VM1 vNIC1's Binding binding[VNIC1 MAC addr, IP1 addr, BID1] binding[vNIC1 MAC addr, IP2 addr, BID2] binding[vNIC1 MAC addr, IP3 addr, BID3] Figure 3 Simultaneous multiple connections for Layer 3 Virtual Network Service VM1 (Tenant Systems) | |---------+--------+ | | | | | | vNIC1(TS1) vNIC2(TS2) ..vNICx(TSx) | Wu Expires October 17, 2013 [Page 9] Internet-Draft NVE2NVE April 2013 | | NVE | +-------+------+ | | | VN1 VN2 VN3 Binding Cache Database VM1 vNIC1's Binding binding[VNIC1 MAC addr, VLAN ID1, BID1] binding[vNIC1 MAC addr, VLAN ID2, BID2] binding[vNIC1 MAC addr, VLAN ID3, BID3] Figure 4. Simultaneous multiple connections for Layer 2 Virtual Network Service 4.2. Multihoming support using one TS or vNIC If tenant system are allocated with multiple IP address, Tenant System may use several IP addresses to connect to multiple VNs. Each IP address corresponding to each connection to VN. In order to support connecting to multiple VNs using a single vNIC, Tenant system may create a Binding Identifier (BID) to each IP address that is used to connect to VN. The BID should be unique for a given Tenant System.If the tenant system has only one IP address, the assignment of a BID is not needed until it has multiple IP addresses, at which time all of the IP addresses of TS MUST be mapped to BIDs. BID is suggested to be stored in the mapping table entry at the NVE and Network Virtualization Authority(NVA). 4.3. Interconnection functionality Suppose one VM only hasone vNIC and is corresponding to the tenant system A, when the tenant system A plays the role of interconnection functionality to connect two VNs, the following three cases should be considered. (a) Both two VNs support Layer 3 forwarding; (b) Both two VNs support layer 2 forwarding; (c) One VN supports Layer3 forwarding and the other VN supports layer 2 forwarding; For (a), tenant system A or external system that is close to tenant system A should support layer 3 forwarding functionality. When source tenant system in one VN communicates with destination tenant Wu Expires October 17, 2013 [Page 10] Internet-Draft NVE2NVE April 2013 system in another VN through the tenant system A, if tenant system A support layer 3 forwarding, the tenant system A should forward IP packets on the behalf of source Tenant System and destination tenant system irrespective of data plane encapsulation format(e.g., VXLAN or NVGREW, MPLS over GRE). If two VNs use different data plane encapsulation format, the tenant system A should also support converting one data plane encapsulation format into another. If tenant system A doesn't support layer 3 forwarding,the external system that is close to tenant system A should associate vNIC to local NVE using TS MAC address and VLAN tag information and forward IP packets on the behalf of source tenant system and destination tenant system. For (b), tenant system A vNIC or external system that is close to tenant system A should support layer 2 forwarding functionality. When source tenant system in one VN communicates with destination tenant system in another VN through the tenant system A, if tenant system A support layer 2 forwarding, the tenant system A should know which tenant systems connecting to itself are allowed for layer 2 forwarding and then forward layer 2 frames on the behalf of source Tenant System and destination tenant system based on forwarding allowed list. If two layer 2 VNs support different data plane encapsulation format, the tenant system A should also support converting one data plane encapsulation format to another. If tenant system A doesn't support layer 2 forwarding, the external system that is close to tenant system A should associate vNIC to local NVE using TS MAC address and VLAN tag information and forward layer 2 frames on the behalf of source tenant system and destination tenant system. For (c), tenant system A or external system that is close to tenant system A should support both layer 2 forwarding and layer 3 forwarding. When source tenant systems in layer 2 VN communicates with destination tenant system in layer 3 VN through the tenant system A, if tenant system A support both layer 2 and layer 3 forwarding the tenant system A should support translating layer 2 frame into layer 3 packet and forward traffic between layer 2 VN and layer 3 VN. If two VNs support different data plane encapsulation format, the tenant system A should also support converting one data plane encapsulation format to another. If tenant system A doesn't support layer 2 forwarding or layer3 forwarding, the external system that is close to tenant system A should associate vNIC to local NVE using TS MAC address and VLAN tag information and forward traffic on the behalf of source tenant system and destination tenant system. When the tenant system A plays the role of interconnection functionality to connect between VN and Non-VN, suppose source tenant system in one VN communicates with destination end device in Non-VN environment through the tenant system A, the tenant system A acts as Wu Expires October 17, 2013 [Page 11] Internet-Draft NVE2NVE April 2013 NVO3 GW between VN and Non-VN in this case peering with other Gateways and should be explicitly configured with a list of destination MAC addresses that allows passed to the Non-VN environment and perform translation between VNID and Non-VN label when forwarding traffic between VN interface and Non-VN interface. For outgoing frames on VN connected interface, the tenant system A decapsulates NVO3 outer header and forwards the inner frame to Non-VN environment based on configured allowed list. For incoming frames on non-VN connected interface(e.g.,WAN interface), the tenant system A should map the incoming frames from end device to specific VN based on inner Ethernet frame information (e.g., VLAN ID). The mapping table is setup at the tenant system A to perform VNID lookup in VN and label lookup in the Non-VN environment. Wu Expires October 17, 2013 [Page 12] Internet-Draft NVE2NVE April 2013 5. NVE to Oracle Control plane protocol functionality The core functional entities for NVE to Oracle Control plane infrastructure are the NVE and Oracle backend system. The Oracle backend system is responsible for maintaining the tenant system reachability state and is the topological anchor point for the Tenant system MAC address or Tenant System Name (i.e.,vNIC name). The NVE is the entity that performs the address mapping management on behalf of tenant system, and it resides on the access link where the tenant system is anchored. The NVE is responsible for detecting the VM's movements to and from the access link and for initiating location binding registrations to the tenant system's Oracle backend system. There can be multiple Oracle backend system in a VN each serving a different group of tenant system. 5.1. NVE connect/disconnect notification When a tenant system connects to one VN by attaching to a local NVE, the local NVE should also be added into VN context together with tenant system information. This helps Network Virtualization Authority or Oracle Backend System know with which NVE a group of the tenant systems are attached or current location of these tenant systems. When the last tenant system is disconnected to one VN through one local NVE, this local NVE should also be removed from VN context. This should also be updated to Network Virtualization Authority or Oracle Backend system and let Oracle backend system know that there are no tenant system associated with that NVE. 5.2. VN membership Registration and Query In order to enable tenant system A to communicate with any tenant system that is not under the same local NVE, the mapping table should be distributed to all the remote NVEs that belong to the same VN even though there is no tenant system which communicates with tenant system A behind that remote NVE. However how should local NVE know a list of remote NVEs that belong to the same VN as local NVE? In order to tackle this, when a tenant system connects to one VN by attaching to a local NVE, VN membership (e.g., VNID, VN Name, a list of NVE that belong to VN) should be registered to the Network Virtualization Authority or Oracle Backend system. When local NVE needs to know which remote NVEs it should forward a data packet, Network Virtualization Authority or Oracle backend system can be queried by the local NVE. The Network Virtualization Authority or Oracle backend system can redirect the query from local NVE to the remote NVEs based on VN membership registration and obtain answer from the right remote NVE. In addition, VM membership may contain detailed mapping between tenant system, NVE and VN in the form of TESID=. In this case, The Network Virtualization Wu Expires October 17, 2013 [Page 13] Internet-Draft NVE2NVE April 2013 Authority or Oracle backend system can directly supply answer for the request from the local NVE. 5.3. Address Mapping information reflection/distribution Data plane learning can be used to build mapping table without need for control plane protocol. However it requires each data packet to be flooded to the whole VN. In order to eliminate flooding introduced by data plane learning, a control protocol is needed to provide both MAC address and IP address in the form of mapping information. When VN membership registration complete, the NVE can forward such address mapping information directly to all the remote NVEs based on VN membership, alternatively, the NVE also can forward such address mapping information indirectly to the Network Virtualization Authority or Oracle backend system and let the Network Virtualization Authority or Oracle backend system to reflect the address mapping information to all the relevant remote NVEs based on VN membership. 5.4. VN context moving In some cases, one tenant system may be detached from one NVE and move to another NVE. In such cases, the VN context should be moved from the NVE to which the tenant system was previously attached to the new NVE to which the tenant system is currently attached. In order to achieve this, the per tenant system VN context including VN profile can be maintained at the Network Virtualization Authority or Oracle backend system and be retrieved at the new place based on the VN Identifier (VNID). Wu Expires October 17, 2013 [Page 14] Internet-Draft NVE2NVE April 2013 6. Hypervisor-to-NVE Control Plane Protocol Functionality 6.1. Multiple addresses association of one TS Typically, a TS or vNIC is assigned a single MAC address and a single IP address. However, a TS may be assigned multiple IP addresses with each to connect to one VN. In such case, BID may be assigned for each IP address of TS when tenant system wants to register multiple IP address with its MAC address simultaneously to the local NVE. If a tenant system has only one IP address, the assignment of a BID is not needed until it has multiple IP addresses to register with, at which time all of the IP addresses of TS MUST be mapped to BIDs. When a tenant system registers a given BID for the first time it MUST send BID together with the IP address. For any subsequent registrations that either re-register or de-register the same BID, the TS only need send BID and does not need to send IP address associated with BID. Wu Expires October 17, 2013 [Page 15] Internet-Draft NVE2NVE April 2013 7. Key functions aspect for signaling control/forwarding info to NVEs 7.1. Create and Update tenant Virtual Network (VN) The tenant virtualization network(VN) is a collection of tenant systems, Network Virtualization Edges (NVE)(s) and other end systems that are interconnected with each other. The tenant VN also consists of a set of sites where each can send traffic directly to the other. In order to create or update a tenant VN, when a Tenant System is attached to a local NVE, the tenant system should inform the attached local NVE which VN the tenant system belong to. o If the tenant system are the first participant in the VN through the local NVE, the tenant system and associated local NVE should be firstly added to the VN and the mapping table should be setup at the local NVE for each attached tenant system. o If both the tenant system and the local NVE are not on the VN, the tenant system and associated local should be firstly added to the VN and then the mapping table associated with this tenant system should be setup at the local NVE and distributed to the other remote NVEs that belong to the same VN. o If the local NVE is on the same tenant VN as the tenant system associated with the local NVE, only the tenant system needs to be added into the VN, i.e., the local NVE only needs to distribute mapping table at the local NVE to the other remote NVEs that belong to the same tenant VN. o If the local NVE is not on the same tenant VN as the tenant system associated with that local NVE, the local NVE should firstly be added into the VN and then distributes the new mapping table at the local NVE to the other remote NVEs that belong to the same tenant VN. o If one tenant system is the last participant connecting to the VN through local NVE, when this tenant system leave the VN, the local NVE associated with this tenant system should be removed from the VN.The mapping table associated with this tenant system should be removed from the local NVE associated with this tenant system. 7.2. Associate the NVE and tenant system with VN context The VN context includes a set of configuration attributes defining access and tunnel policies and (L2 and/or L3) forwarding functions. When a Tenant System is attached to a local NVE, a VN network instance should be allocated to the local NVE. The tenant system Wu Expires October 17, 2013 [Page 16] Internet-Draft NVE2NVE April 2013 should be associated with the specific VN context using virtual Network Instance(VNI). The tenant system should also inform the attached local NVE which VN context the tenant system belong to. Therefore the VN context can be bound with the data path from the tenant system to the local NVE and the tunnel from local NVE associated with the tenant system and all the remote NVEs that belong to the same VN as the local NVE. For the data path from the tenant system and the local NVE, the network policy can be installed on the underlying switched network and forwarding tables also can be populated to each network elements in the underlying network based on the specific VNI associated with the tenant system. For the tunnel from local NVE to the remote NVEs, the traffic engineering information can be applied to each tunnel based on VNI associated with the tenant system. 7.3. Populate mapping tables information at the local NVE In some cases, two tenant systems may be attached to the same local NVE. In order to allow the NVE to locally route traffic between two tenant systems that are attached to the same NVE, the mapping table that maps a final destination address to the proper tunnel should be populated at the local NVE. In some cases, two tenant systems may connect to the different VNs through the same interconnection functionality, in order to allow two tenant systems communication between two VNs, the mapping table that maps a final destination address to the proper tunnel should be populated in both NVE associated with two communicated tenant system and the interconnection functionality associated corresponding NVE. 7.4. Distribute the mapping table information to remote NVEs in the VN When the packet sent from one tenant system arrives at the ingress NVE associated with that tenant system, in order to determine which tunnel the packet needs to be sent to, the mapping table that maps a final destination address to the proper tunnel should also be distributed to all the remote NVEs in the VN using a control plane protocol or dynamic data plane learning. The mapping table may be advertised directly to other remote NVEs that belong to the same VN or firstly advertised to the centralized controller that maintain global view of NVEs that belong to the same VN and then let the centralized controller distribute the mapping tables to all the relevant remote NVEs that belong to the same VN. 7.5. The mapping table information update at the NVE when VM moves or connection fails In some cases, one tenant system may be detached from one NVE and Wu Expires October 17, 2013 [Page 17] Internet-Draft NVE2NVE April 2013 move to another NVE. In such cases, the mapping table should be removed from the NVE to which the tenant system was previously attached and the new mapping table should be created at the new NVE to which the tenant system is currently attached. Such mapping table should be updated at each remote NVE associated with the tenant system and the centralized controller,e.g., the Network Virtualization Authority or Oracle Backend system. In some cases, one tenant system may fail to connect to the VN through the NVE. In such cases, the mapping table should be removed from the NVE to which the tenant system is currently attached. In addition, the mapping table should be updated at each remote NVE in the same VN through which the tenant system is communicating with the destination tenant system. 7.6. The VN context re-association at the NVE when VM moves In some cases, one tenant system may be detached from one NVE and move to another NVE. In such cases, the VN context should be moved from the NVE to which the tenant system was previously attached to the new NVE to which the tenant system is currently attached. In order to achieve this, the per tenant system VN context can be maintained at the centralized database and be retrieved at the new place based on the VN Identifier (VNID). Wu Expires October 17, 2013 [Page 18] Internet-Draft NVE2NVE April 2013 8. IANA Considerations This document has no actions for IANA. Wu Expires October 17, 2013 [Page 19] Internet-Draft NVE2NVE April 2013 9. Security Considerations TBC. Wu Expires October 17, 2013 [Page 20] Internet-Draft NVE2NVE April 2013 10. References 10.1. Normative References [I.D-ietf-nvo3-framework] Lasserre, M., "Framework for DC Network Virtualization", ID draft-ietf-nvo3-framework-00, September 2012. [I.D-ietf-nvo3-overlay-problem-statement] Narten, T., "Problem Statement: Overlays for Network Virtualization", ID draft-ietf-nvo3-overlay-problem-statement-02, Feburary 2013. [I.D-kreeger-nvo3-hypervisor-nve-cp] Kreeger, L., "Network Virtualization Hypervisor-to-NVE Overlay Control Protocol Requirements", ID draft-kreeger-nvo3-hypervisor-nve-cp-01, Feburary 2013. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", March 1997. 10.2. Informative References [I.D-fw-nvo3-server2vcenter] Wu, Q. and R. Scott, "Network Virtualization Architecture", ID draft-fw-nvo3-server2vcenter-01, January 2013. Wu Expires October 17, 2013 [Page 21] Internet-Draft NVE2NVE April 2013 Author's Address Qin Wu Huawei 101 Software Avenue, Yuhua District Nanjing, Jiangsu 210012 China Email: bill.wu@huawei.com Wu Expires October 17, 2013 [Page 22]