Network Working Group F. Maino Internet-Draft V. Ermagan Intended status: Experimental D. Farinacci Expires: April 25, 2013 Cisco Systems M. Smith Insieme Networks October 22, 2012 LISP Control Plane for Network Virtualization Overlays draft-maino-nvo3-lisp-cp-02 Abstract The purpose of this draft is to analyze the mapping between the Network Virtualization over L3 (NVO3) requirements and the capabilities of the Locator/ID Separation Protocol (LISP) control plane. This information is provided as input to the NVO3 analysis of the suitability of existing IETF protocols to the NVO3 requirements. Requirements Language 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]. 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 April 25, 2013. Copyright Notice Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved. Maino, et al. Expires April 25, 2013 [Page 1] Internet-Draft LISP Control Plane for NVO3 October 2012 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 . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Definition of Terms . . . . . . . . . . . . . . . . . . . . . 4 3. LISP Overview . . . . . . . . . . . . . . . . . . . . . . . . 4 3.1. LISP Site Configuration . . . . . . . . . . . . . . . . . 6 3.2. End System Provisioning . . . . . . . . . . . . . . . . . 7 3.3. End System Registration . . . . . . . . . . . . . . . . . 7 3.4. Packet Flow and Control Plane Operations . . . . . . . . . 7 3.4.1. Supporting ARP Resolution with LISP Mapping System . . 8 3.5. End System Mobility . . . . . . . . . . . . . . . . . . . 10 3.6. L3 LISP . . . . . . . . . . . . . . . . . . . . . . . . . 12 4. Reference Model . . . . . . . . . . . . . . . . . . . . . . . 13 4.1. Generic LISP NVE Reference Model . . . . . . . . . . . . . 13 4.2. LISP NVE Service Types . . . . . . . . . . . . . . . . . . 14 4.2.1. LISP L2 NVE Services . . . . . . . . . . . . . . . . . 14 4.2.2. LISP L3 NVE Services . . . . . . . . . . . . . . . . . 14 5. Functional Components . . . . . . . . . . . . . . . . . . . . 14 5.1. Generic Service Virtualization Components . . . . . . . . 14 5.1.1. Virtual Attachment Points (VAPs) . . . . . . . . . . . 15 5.1.2. Overlay Modules and Tenant ID . . . . . . . . . . . . 15 5.1.3. Tenant Instance . . . . . . . . . . . . . . . . . . . 16 5.1.4. Tunnel Overlays and Encapsulation Options . . . . . . 16 5.1.5. Control Plane Components . . . . . . . . . . . . . . . 16 6. Key Aspects of Overlay . . . . . . . . . . . . . . . . . . . . 17 6.1. Overlay Issues to Consider . . . . . . . . . . . . . . . . 17 6.1.1. Data Plane vs. Control Plane Driven . . . . . . . . . 17 6.1.2. Data Plane and Control Plane Separation . . . . . . . 17 6.1.3. Handling Broadcast, Unknown Unicast and Multicast (BUM) Traffic . . . . . . . . . . . . . . . . . . . . 17 7. Security Considerations . . . . . . . . . . . . . . . . . . . 18 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 18 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18 10.1. Normative References . . . . . . . . . . . . . . . . . . . 18 10.2. Informative References . . . . . . . . . . . . . . . . . . 19 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20 Maino, et al. Expires April 25, 2013 [Page 2] Internet-Draft LISP Control Plane for NVO3 October 2012 1. Introduction The purpose of this draft is to analyze the mapping between the Network Virtualization over L3 (NVO3) [I-D.ietf-nvo3-overlay-problem-statement] requirements and the capabilities of the Locator/ID Separation Protocol (LISP) [I-D.ietf-lisp] control plane. This information is provided as input to the NVO3 analysis of the suitability of existing IETF protocols to the NVO3 requirements. LISP is a flexible map and encap framework that can be used for overlay network applications, including Data Center Network Virtualization. The LISP framework provides two main tools for NVO3: (1) a Data Plane that specifies how Endpoint Identifiers (EIDs) are encapsulated in Routing Locators (RLOCs), and (2) a Control Plane that specifies the interfaces to the LISP Mapping System that provides the mapping between EIDs and RLOCs. This document focuses on the control plane for L2 over L3 LISP encapsulation, where EIDs are associated with MAC addresses. As such the LISP control plane can be used with the data path encapsulations defined in VXLAN [I-D.mahalingam-dutt-dcops-vxlan] and in NVGRE [I-D.sridharan-virtualization-nvgre]. The LISP control plane can, of course, be used with the L2 LISP data path encapsulation defined in [I-D.smith-lisp-layer2]. The LISP control plane provides the Mapping Service for the Network Virtualization Edge (NVE), mapping per-tenant end system identity information on the corresponding location at the NVE. As required by NVO3, LISP supports network virtualization and tenant separation to hide tenant addressing information, tenant-related control plane activity and service contexts from the underlay network. The LISP control plane is extensible, and can support non-LISP data path encapsulations such as [I-D.sridharan-virtualization-nvgre], or other encapsulations that provide support for network virtualization. [I-D.ietf-lisp-interworking] specifies an open interworking framework to allow LISP to non-LISP sites communication. Broadcast, unknown unicast, and multicast in the overlay network are supported by either replicated unicast, or core-based multicast as specified in [I-D.ietf-lisp-multicast], [I-D.farinacci-lisp-mr-signaling], and [I-D.farinacci-lisp-te]. Finally, the LISP architecture has a modular design that allows the use of different Mapping Databases, provided that the interface to Maino, et al. Expires April 25, 2013 [Page 3] Internet-Draft LISP Control Plane for NVO3 October 2012 the Mapping System remains the same [I-D.ietf-lisp-ms]. This allows for different Mapping Databases that may fit different NVO3 deployments. As an example of the modularity of the LISP Mapping System, a worldwide LISP pilot network is currently using an hierarchical Delegated Database Tree [I-D.fuller-lisp-ddt], after having been operated for years with an overlay BGP mapping infrastructure [I-D.ietf-lisp-alt]. The LISP mapping system supports network virtualization, and a single mapping infrastructure can run multiple instances, either public or private, of the mapping database. The rest of this document, after giving a quick a LISP overview in Section 3, follows the functional model defined in [I-D.lasserre-nvo3-framework] that provides in Section 4 an overview of the LISP NVO3 reference model, and in Section 5 a description of its functional components. Section 6 contains various considerations on key aspects of LISP NVO3, followed by security considerations in Section 7. 2. Definition of Terms Flood-and-Learn: the use of dynamic (data plane) learning in VXLAN to discover the location of a given Ethernet/IEEE 802 MAC address in the underlay network. ARP-Agent Reply: the ARP proxy-reply of an agent (e.g. an ITR) with a MAC address of some other system in response to an ARP request to a target which is not the agent's IP address For definition of NVO3 related terms, notably Virtual Network (VN), Virtual Network Identifier (VNI), Network Virtualization Edge (NVE), Data Center (DC), please consult [I-D.lasserre-nvo3-framework]. For definitions of LISP related terms, notably Map-Request, Map- Reply, Ingress Tunnel Router (ITR), Egress Tunnel Router (ETR), Map- Server (MS) and Map-Resolver (MR) please consult the LISP specification [I-D.ietf-lisp]. 3. LISP Overview This section provides a quick overview of L2 LISP, with focus on control plane operations. The modular and extensible architecture of the LISP control plane allows its use with both L2 or L3 LISP data path encapsulation. In Maino, et al. Expires April 25, 2013 [Page 4] Internet-Draft LISP Control Plane for NVO3 October 2012 fact, the LISP control plane can be used even with other L2 overlay data path encapsulations such as VXLAN and NVGRE. When used with VXLAN, the LISP control plane replaces the use of dynamic data plane learning (Flood-and-Learn), as specified in [I-D.mahalingam-dutt-dcops-vxlan] improving scalability and mitigating multicast requirements in the underlay network. For a detailed LISP overview please refer to [I-D.ietf-lisp] and related drafts. To exemplify LISP operations let's consider two data centers (LISP sites) A and B that provide L2 network virtualization services to a number of tenant end systems, as depicted in Figure 1. The Endpoint Identifiers (EIDs) are encoded according to [I-D.ietf-lisp-lcaf] as an tuple that contains the Instance ID, or Virtual Network Identifier (VNI), and the endpoint Ethernet/IEEE 802 MAC address. The data centers are connected via a L3 underlay network, hence the Routing Locators (RLOCs) are IP addresses (either IPv4 or IPv6) encoded according to [I-D.ietf-lisp-lcaf]. In LISP the network virtualization edge function is performed by Ingress Tunnel Routers (ITRs) that are responsible for encapsulating the LISP ingress traffic, and Egress Tunnel Routers (ETRs) that are responsible for decapsulating the LISP egress traffic. ETRs are also responsible to register the EID-to-RLOC mapping for a given LISP site in the LISP mapping database system. ITRs and ETRs are collectively referred as xTRs. The EID-to-RLOC mapping is stored in the LISP mapping database, a distributed mapping infrastructure accessible via Map Servers (MS) and Map Resolvers (MR). [I-D.fuller-lisp-ddt] is an example of a mapping database used in many LISP deployments. Another example of of mapping database is [I-D.ietf-lisp-alt]. For small deployments the mapping infrastructure can be very minimal, in some cases even a single system running as MS/MR. Maino, et al. Expires April 25, 2013 [Page 5] Internet-Draft LISP Control Plane for NVO3 October 2012 ,---------. ,' `. (Mapping System ) `. ,' `-+------+' +--+--+ +-+---+ |MS/MR| |MS/MR| +-+---+ +-----+ | | .--..--. .--. .. ( ' '.--. .-.' L3 ' ( Underlay ) ( '-' ._.'--'._.'.-._.'.-._) RLOC=IP_A // \\ RLOC=IP_B +---+--+ +-+--+--+ .--.-.|xTR A |'.-. .| xTR B |.-. ( +---+--+ ) ( +-+--+--+ ) ( __. ( '. ..' LISP Site A ) .' LISP Site B ) ( .'-' ( .'-' '--'._.'. )\ '--'._.'. )\ / '--' \ / '--' \ '--------' '--------' '--------' '--------' : End : : End : : End : : End : : Device : : Device : : Device : : Device : '--------' '--------' '--------' '--------' EID= EID= EID= EID= Figure 1: Example of L2 NVO3 Services 3.1. LISP Site Configuration In each LISP site the xTRs are configured with an IP address (the site RLOCs) per each interface facing the underlay network. Similarly the MS/MR are assigned an IP address in the RLOC space. The configuration of the xTRs includes the RLOCs of the MS/MR and a shared secret that is optionally used to secure the communication between xTRs and MS/MR. To provide support for multi-tenancy multiple instances of the mapping database are identified by a LISP Instance ID (IID), that is equivalent to the 24-bit VXLAN Network Identifier (VNI) or Tenant Network Identifier (TNI) that identifies tenants in Maino, et al. Expires April 25, 2013 [Page 6] Internet-Draft LISP Control Plane for NVO3 October 2012 [I-D.mahalingam-dutt-dcops-vxlan]. 3.2. End System Provisioning We assume that a provisioning framework will be responsible for provisioning end systems (e.g. VMs) in each data center. The provisioning configures each end system with an Ethernet/IEEE 802 MAC address and provision the network with other end system specific attributes such as IP addresses, and VLAN information. LISP does not introduce new addressing requirements for end systems. The provisioning infrastructure is also responsible to provide a network attach function, that notifies the network virtualization edge (the LISP site ETR) that the end system is attached to a given virtual network (identified by its VNI/IID) and that the end system is identified, within that virtual network, by a given Ethernet/IEEE 802 MAC address. 3.3. End System Registration Upon notification of end system network attach, that includes the EID= tuple that identifies that end system, the ETR sends a LISP Map-Register to the Mapping System. The Map-Register includes the EID and RLOCs of the LISP site. The EID-to-RLOC mapping is now available, via the Mapping System Infrastructure, to other LISP sites that are hosting end systems that belong to the same tenant. For more details on end system registration see [I-D.ietf-lisp-ms]. 3.4. Packet Flow and Control Plane Operations This section provides an example of the unicast packet flow and the control plane operations when in the topology shown in Figure 1 end system W, in LISP site A, wants to communicate to end system Y in LISP site B. We'll assume that W knows Y's EID MAC address (e.g. learned via ARP). o W sends an Ethernet/IEEE 802 MAC frame with destination EID= and source EID=. o ITR A does a lookup in its local map-cache for the destination EID=. Since this is the first packet sent to MAC_Y, the map-cache is a miss, and the ITR sends a Map-request to the mapping database system looking up the EID=. o The mapping systems forwards the Map-Request to ETR B, that is aware of the EID-to-RLOC mapping for . Alternatively, depending on the mapping system configuration, a Map-Server which Maino, et al. Expires April 25, 2013 [Page 7] Internet-Draft LISP Control Plane for NVO3 October 2012 is part of the mapping database system may send a Map-Reply directly to ITR A. o ETR B sends a Map-Reply to ITR A that includes the EID-to-RLOC mapping: EID= -> RLOC=IP_B, where IP_B is the locator of ETR B, hence the locator of LISP site B. In order to facilitate interoperability, the Map-Reply may also include attributes such as the data plane encapsulations supported by the ETR. o ITR A populates the local map-cache with the EID to RLOC mapping, and either L2 LISP, VXLAN, or NVGRE encapsulates all subsequent packets with a destination EID= with a destination RLOC=IP_B. It should be noted how the LISP mapping system replaces the use of Flood-and-Learn based on multicast distribution trees instantiated in the underlay network (required by VXLAN's dynamic data plane learning), with a unicast control plane and a cache mechanism that "pulls" on-demand the EID-to-RLOC mapping from the LISP mapping database. This improves scalability, and simplifies the configuration of the underlay network. 3.4.1. Supporting ARP Resolution with LISP Mapping System A large majority of data center applications are IP based, and in those use cases end systems are provisioned with IP addresses as well as MAC addresses. In this case, to eliminate the flooding of ARP traffic and further reduce the need for multicast in the underlay network, the LISP mapping system is used to support ARP resolution at the ITR. We assume that as shown in Figure 2: (1) end system W has an IP address IP_W, and end system Y has an IP address IP_Y, (2) end system W knows Y's IP address (e.g. via DNS lookup). We also assume that during registration Y has registered both its MAC address and its IP address as EID. End system Y is then identified by the EID = . Maino, et al. Expires April 25, 2013 [Page 8] Internet-Draft LISP Control Plane for NVO3 October 2012 ,---------. ,' `. (Mapping System ) `. ,' `-+------+' +--+--+ +-+---+ |MS/MR| |MS/MR| +-+---+ +-----+ | | .--..--. .--. .. ( ' '.--. .-.' L3 ' ( Underlay ) ( '-' ._.'--'._.'.-._.'.-._) RLOC=IP_A // \\ RLOC=IP_B +---+--+ +-+--+--+ .--.-.|xTR A |'.-. .| xTR B |.-. ( +---+--+ ) ( +-+--+--+ ) ( __. ( '. ..' LISP Site A ) .' LISP Site B ) ( .'-' ( .'-' '--'._.'. )\ '--'._.'. )\ / '--' \ / '--' \ '--------' '--------' '--------' '--------' : End : : End : : End : : End : : Device : : Device : : Device : : Device : '--------' '--------' '--------' '--------' EID= EID= EID= EID= MAC_X> MAC_Y> MAC_Z> Figure 2: Example of L3 NVO3 Services The packet flow and control plane operation are as follows: o End system W sends a broadcast ARP message to discover the MAC address of end system Y. The message contains IP_Y in the ARP message payload. o ITR A, acting as a L2 switch, will receive the ARP message, but rather than flooding it on the overlay network sends a Map-Request to the mapping database system for EID = . o The Map-Request is routed by the mapping system infrastructure to ETR B, that will send a Map-Reply back to ITR A containing the mapping EID= -> RLOC=IP_B, (the locator of ETR B). Alternatively, depending on the mapping system configuration, Maino, et al. Expires April 25, 2013 [Page 9] Internet-Draft LISP Control Plane for NVO3 October 2012 a Map-Server in the mapping system may send directly a Map-Reply to ITR A. o ITR A populates the map-cache with the received entry, and sends an ARP-Agent Reply to W that includes MAC_Y and IP_Y. o End system W learns MAC_Y from the ARP message and can now send a packet to end system Y by including MAC_Y, and IP_Y, as destination addresses. o ITR A will then process the packet as specified in Section 3.4. This example shows how LISP, by replacing dynamic data plane learning (Flood-and-Learn) largely reduces the need for multicast in the underlay network, that is needed only when broadcast, unknown unicast or multicast are required by the applications in the overlay. In practice, the LISP mapping system, constrains ARP within the boundaries of a link-local protocol. This simplifies the configuration of the underlay network and removes the significant scalability limitation imposed by VXLAN Flood-and-Learn. It's important to note that the use of the LISP mapping system, by pulling the EID-to-RLOC mapping on demand, also improves end system mobility across data centers. 3.5. End System Mobility This section shows how the LISP control plane deals with mobility when end systems are migrated from one Data Center to another. We'll assume that a signaling protocol, as described in [I-D.kompella-nvo3-server2nve], signals to the NVE operations such as creating/terminating/migrating an end system. The signaling protocol consists of three basic messages: "associate", "dissociate", and "pre-associate". Let's consider the scenario shown in Figure 3 where end system W moves from data center A to data center B. Maino, et al. Expires April 25, 2013 [Page 10] Internet-Draft LISP Control Plane for NVO3 October 2012 ,---------. ,' `. (Mapping System ) `. ,' `-+------+' +--+--+ +-+---+ |MS/MR| |MS/MR| +-+---+ +-----+ | | .--..--. .--. .. ( ' '.--. .-.' L3 ' ( Underlay ) ( '-' ._.'--'._.'.-._.'.-._) RLOC=IP_A // \\ RLOC=IP_B +---+--+ +-+--+--+ .--.-.|xTR A |'.-. .| xTR B |.-. ( +---+--+ ) ( +-+--+--+ ) ( __. ( '. ..' LISP Site A ) .' LISP Site B ) ( .'-' ( .'-' '--'._.'. )\ '--'._.'. )\ / '--' \ / '--' \ '--------' '--------' '--------' '--------' : End : : End : ==> : End : : End : : Device : : Device : ==> : Device : : Device : '--------' '--------' '--------' '--------' EID= EID= EID= Figure 3: End System Mobility As a result of the end system registration, described in Section 3.3, the Mapping System contains the EID-to-RLOC mapping for end system W that associates EID= with the RLOC(s) associated with LISP site A (IP_A). The process of migrating end system W from data center A to data center B is initiated. ETR B receives a pre-associate message that includes EID=. ETR B sends a Map-Register to the mapping system registering RLOC=IP_B as an additional locator for end system W with priority set to 255. This means that the RLOC MUST NOT be used for unicast forwarding, but the mapping system is now aware of the new location. During the migration process of end system W, ETR A receives a Maino, et al. Expires April 25, 2013 [Page 11] Internet-Draft LISP Control Plane for NVO3 October 2012 dissociate message, and sends a Map-Register with Record TTL=0 to signal the mapping system that end system W is no longer reachable at RLOC=IP_A. xTR A will also add an entry in its forwarding table that marks EID= as non-local. When end system W has completed its migration, ETR B receives an associate message for end system W, and sends a Map-Register to the mapping system setting a non-255 priority for RLOC=IP_B. Now the mapping system is updated with the new EID-to-RLOC mapping for end system W with the desired priority. The remote ITRs that were corresponding with end system W during the migration will keep sending packets to ETR A. ETR A will keep forwarding locally those packets until it receives a dissociate message, and the entry in the forwarding table associated with EID= is marked as non-local. Subsequent packets arriving at ETR A from a remore ITR, and destined to end system W will hit the entry in the forwarding table that will generate an exception, and will generate a Solicit-Map-Request (SMR) message that is returned to the remote ITR. Upon receiving the SMR the remote ITR will invalidate its local map-cache entry for EID= and send a new Map-Request for that EID. The Map-Request will generate a Map-Reply that includes the new EID-to-RLOC mapping for end system W with RLOC=IP_B. Similarly, unencapsulated packets arriving at ITR A from local end systems and destined to end system W will hit the entry in the forwarding table marked as non-local, and will generate an exception that by sending a Map-Request for EID= will populate the map-cache of ITR A with an EID-to-RLOC mapping for end system W with RLOC=IP_B. 3.6. L3 LISP The two examples above shows how the LISP control plane can be used in combination with either L2 LISP, VXLAN, or NVGRE encapsulation to provide L2 network virtualization services across data centers. There is a trend, led by Massive Scalable Data Centers, that is accelerating the adoption of L3 network services in the data center, to preserve the many benefits introduced by L3 (scalability, multi- homing, ...). LISP, as defined in [I-D.ietf-lisp], provides L3 network virtualization services over an L3 underlay network that, as an alternative to L2 overlay solutions, matches the requirements for DC Network Virtualization. L2 overlay solutions are necessary for Data Centers that rely on non IPv4/IPv6 protocols, but when IP is pervasive L3 LISP provides a better and more scalable overlay. Maino, et al. Expires April 25, 2013 [Page 12] Internet-Draft LISP Control Plane for NVO3 October 2012 4. Reference Model 4.1. Generic LISP NVE Reference Model In the generic NVO3 reference model described in [I-D.lasserre-nvo3-framework], a Tenant End System attaches to a Network Virtualization Edge (NVE) either directly or via a switched network. In a LISP NVO3 network the Tenant End Systems are part of a LISP site, and the NVE function is provided by LISP xTRs. xTRs provide for tenant separation, perform the encap/decap function, and interface with the LISP Mapping System that maps tenant addressing information (in the EID name space) on the underlay L3 infrastructure (in the RLOC name space). Tenant segregation across LISP sites is provided by the LISP Instance ID (IID), a 24-bit value that is used by the LISP routers as the Virtual Network Identifier (VNI). Virtualization and Segmentation with LISP is addressed in section 5.5 of [I-D.ietf-lisp]. ............... ,---------. .............. . +--------+ . ,' `. . +--------+ . . | Tenant | . (Mapping System ) . | Tenant | . . | End +---+ `. ,' +---| End | . . | System | . | `-+------+' | . | System | . . +--------+ . | ................... | . +--------+ . . . | +-+--+ +--+-+ | . . . . | | NV | | NV | | . . . LISP Site . +--|Edge| |Edge|--+ . LISP Site . . . +-+--+ +--+-+ . . . . / (xTR) L3 Overlay (xTR)\ . . . +--------+ . / . Network . \ . +--------+. . | Tenant +---+ . . +----| Tenant |. . | End | . . (xTR) . . | End |. . | System | . . +----+ . . | System |. . +--------+ . .....| NV |........ . +--------+. ............... |Edge| ............. +----+ .........|............ . |LISP Site . . | . . +--------+ . . | Tenant | . . | End | . . | System | . . +--------+ . Maino, et al. Expires April 25, 2013 [Page 13] Internet-Draft LISP Control Plane for NVO3 October 2012 ...................... Generic reference model for DC NVO3 LISP infrastructure 4.2. LISP NVE Service Types LISP can be used to support both L2 NVE and L3 NVE service types thanks to the flexibility provided by the LISP Canonical Address Format [I-D.ietf-lisp-lcaf], that allows for EIDs to be encoded either as MAC addresses or IP addresses. 4.2.1. LISP L2 NVE Services The frame format defined in [I-D.mahalingam-dutt-dcops-vxlan], has a header compatible with the LISP data path encapsulation header, when MAC addresses are used as EIDs, as described in section 4.12.2 of [I-D.ietf-lisp-lcaf]. The LISP control plane is extensible, and can support non-LISP data path encapsulations such as NVGRE [I-D.sridharan-virtualization-nvgre], or other encapsulations that provide support for network virtualization. 4.2.2. LISP L3 NVE Services LISP is defined as a virtualized IP routing and forwarding service in [I-D.ietf-lisp], and as such can be used to provide L3 NVE services. 5. Functional Components This section describes the functional components of a LISP NVE as defined in Section 3 of [I-D.lasserre-nvo3-framework]. 5.1. Generic Service Virtualization Components The generic reference model for NVE is depicted in Section 3.1 of [I-D.lasserre-nvo3-framework]. Maino, et al. Expires April 25, 2013 [Page 14] Internet-Draft LISP Control Plane for NVO3 October 2012 +------- L3 Network ------+ | | | Tunnel Overlay | +------------+---------+ +---------+------------+ | +----------+-------+ | | +---------+--------+ | | | Overlay Module | | | | Overlay Module | | | +---------+--------+ | | +---------+--------+ | | |VN context| | VN context| | | | | | | | | +--------+-------+ | | +--------+-------+ | | | VNI | | | | VNI | | NVE1 | +-+------------+-+ | | +-+-----------+--+ | NVE2 | | VAPs | | | | VAPs | | +----+------------+----+ +----+------------+----+ | | | | -------+------------+-----------------+------------+------- | | Tenant | | | | Service IF | | Tenant End Systems Tenant End Systems Generic reference model for NV Edge 5.1.1. Virtual Attachment Points (VAPs) In a LISP NVE, Tunnel Routers (xTRs) implement the NVE functionality on ToRs or Virtual Switches. Tenant End Systems attach to the Virtual Access Points (VAPs) provided by the xTRs (either a physical port or a virtual interface). 5.1.2. Overlay Modules and Tenant ID The xTR also implements the function of NVE Overlay Module, by mapping the addressing information (EIDs) of the tenant packet on the appropriate locations (RLOCs) in the underlay network. The Tenant Network Identifier (TNI) is encoded in the encapsulated packet (either in the 24-bit IID field of the LISP header for L2/L3 LISP encapsulation, or in the 24-bit VXLAN Network Identifier field for VXLAN encapsulation, or in the 24-bit NVGRE Tenant Network Identifier field of NVGRE). In a LISP NVE globally unique (per administrative domain) TNIs are used to identify the Tenant instances. The mapping of the tenant packet address onto the underlay network location is "pulled" on-demand from the mapping system, and cached at the NVE in a per-TNI map-cache. Maino, et al. Expires April 25, 2013 [Page 15] Internet-Draft LISP Control Plane for NVO3 October 2012 5.1.3. Tenant Instance Tenants are mapped on LISP Instance IDs (IIDs), and the xTR keeps an instance of the LISP control protocol per each IID. The ETR is responsible to register the Tenant End System to the LISP mapping system, via the Map-Register service provided by LISP Map-Servers (MS). The Map-Register includes the IID that is used to identify the tenant. 5.1.4. Tunnel Overlays and Encapsulation Options The LISP control protocol, as defined today, provides support for L2 LISP and VXLAN L2 over L3 encapsulation, and LISP L3 over L3 encapsulation. We believe that the LISP control Protocol can be easily extended to support different IP tunneling options (such as NVGRE). 5.1.5. Control Plane Components 5.1.5.1. Auto-provisioning/Service Discovery The LISP framework does not include mechanisms to provision the local NVE with the appropriate Tenant Instance for each Tenant End Systems. Other protocols, such as VDP (in IEEE P802.1Qbg), should be used to implement a network attach/detach function. The LISP control plane can take advantage of such a network attach/ detach function to trigger the registration of a Tenant End System to the Mapping System. This is particularly helpful to handle mobility across DC of the Tenant End System. It is possible to extend the LISP control protocol to advertise the tenant service instance (tenant and service type provided) to other NVEs, and facilitate interoperability between NVEs that are using different service types. 5.1.5.2. Address Advertisement and Tunnel mapping As traffic reaches an ingress NVE, the corresponding ITR uses the LISP Map-Request/Reply service to determine the location of the destination End System. The LISP mapping system combines the distribution of address advertisement and (stateless) tunneling provisioning. When EIDs are mapped on both IP addresses and MACs, the need to flood ARP messages at the NVE is eliminated resolving the issues with Maino, et al. Expires April 25, 2013 [Page 16] Internet-Draft LISP Control Plane for NVO3 October 2012 explosive ARP handling. 5.1.5.3. Tunnel Management LISP defines several mechanisms for determining RLOC reachability, including Locator Status Bits, "nonce echoing", and RLOC probing. Please see Sections 5.3 and 6.3 of [I-D.ietf-lisp]. 6. Key Aspects of Overlay 6.1. Overlay Issues to Consider 6.1.1. Data Plane vs. Control Plane Driven The use of LISP control plane minimizes the need for multicast in the underlay network overcoming the scalability limitations of VXLAN dynamic data plane learning (Flood-and-Learn). Multicast or ingress replication in the underlay network are still required, as specified in [I-D.ietf-lisp-multicast], [I-D.farinacci-lisp-mr-signaling], and [I-D.farinacci-lisp-te], to support broadcast, unknown, and multicast traffic in the overlay, but multicast in the underlay is no longer required (at least for IP traffic) for unicast overlay services. 6.1.2. Data Plane and Control Plane Separation LISP introduces a clear separation between data plane and control plane functions. LISP modular design allows for different mapping databases, to achieve different scalability goals and to meet requirements of different deployments. 6.1.3. Handling Broadcast, Unknown Unicast and Multicast (BUM) Traffic Packet replication in the underlay network to support broadcast, unknown unicast and multicast overlay services can be done by: o Ingress replication o Use of underlay multicast trees [I-D.ietf-lisp-multicast] specifies how to map a multicast flow in the EID space during distribution tree setup and packet delivery in the underlay network. LISP-multicast doesn't require packet format changes in multicast routing protocols, and doesn't impose changes in the internal operation of multicast in a LISP site. The only operational changes are required in PIM-ASM [RFC4601], MSDP Maino, et al. Expires April 25, 2013 [Page 17] Internet-Draft LISP Control Plane for NVO3 October 2012 [RFC3618], and PIM-SSM [RFC4607]. 7. Security Considerations [I-D.ietf-lisp-sec] defines a set of security mechanisms that provide origin authentication, integrity and anti-replay protection to LISP's EID-to-RLOC mapping data conveyed via mapping lookup process. LISP- SEC also enables verification of authorization on EID-prefix claims in Map-Reply messages. Additional security mechanisms to protect the LISP Map-Register messages are defined in [I-D.ietf-lisp-ms]. The security of the Mapping System Infrastructure depends on the particular mapping database used. The [I-D.fuller-lisp-ddt] specification, as an example, defines a public-key based mechanism that provides origin authentication and integrity protection to the LISP DDT protocol. 8. IANA Considerations This document has no IANA implications 9. Acknowledgements The authors want to thank Victor Moreno and Paul Quinn for the early review, insightful comments and suggestions. 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. [RFC3618] Fenner, B. and D. Meyer, "Multicast Source Discovery Protocol (MSDP)", RFC 3618, October 2003. [RFC4601] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas, "Protocol Independent Multicast - Sparse Mode (PIM-SM): Protocol Specification (Revised)", RFC 4601, August 2006. [RFC4607] Holbrook, H. and B. Cain, "Source-Specific Multicast for IP", RFC 4607, August 2006. Maino, et al. Expires April 25, 2013 [Page 18] Internet-Draft LISP Control Plane for NVO3 October 2012 10.2. Informative References [I-D.farinacci-lisp-mr-signaling] Farinacci, D. and M. Napierala, "LISP Control-Plane Multicast Signaling", draft-farinacci-lisp-mr-signaling-00 (work in progress), July 2012. [I-D.farinacci-lisp-te] Farinacci, D., Lahiri, P., and M. Kowal, "LISP Traffic Engineering Use-Cases", draft-farinacci-lisp-te-00 (work in progress), March 2012. [I-D.fuller-lisp-ddt] Fuller, V. and D. Lewis, "LISP Delegated Database Tree", draft-fuller-lisp-ddt-01 (work in progress), March 2012. [I-D.ietf-lisp] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "Locator/ID Separation Protocol (LISP)", draft-ietf-lisp-23 (work in progress), May 2012. [I-D.ietf-lisp-alt] Fuller, V., Farinacci, D., Meyer, D., and D. Lewis, "LISP Alternative Topology (LISP+ALT)", draft-ietf-lisp-alt-10 (work in progress), December 2011. [I-D.ietf-lisp-interworking] Lewis, D., Meyer, D., Farinacci, D., and V. Fuller, "Interworking LISP with IPv4 and IPv6", draft-ietf-lisp-interworking-06 (work in progress), March 2012. [I-D.ietf-lisp-lcaf] Farinacci, D., Meyer, D., and J. Snijders, "LISP Canonical Address Format (LCAF)", draft-ietf-lisp-lcaf-00 (work in progress), August 2012. [I-D.ietf-lisp-ms] Fuller, V. and D. Farinacci, "LISP Map Server Interface", draft-ietf-lisp-ms-14 (work in progress), December 2011. [I-D.ietf-lisp-multicast] Farinacci, D., Meyer, D., Zwiebel, J., and S. Venaas, "LISP for Multicast Environments", draft-ietf-lisp-multicast-14 (work in progress), February 2012. [I-D.ietf-lisp-sec] Maino, et al. Expires April 25, 2013 [Page 19] Internet-Draft LISP Control Plane for NVO3 October 2012 Maino, F., Ermagan, V., Cabellos-Aparicio, A., Saucez, D., and O. Bonaventure, "LISP-Security (LISP-SEC)", draft-ietf-lisp-sec-02 (work in progress), March 2012. [I-D.ietf-nvo3-overlay-problem-statement] Narten, T., Black, D., Dutt, D., Fang, L., Gray, E., Kreeger, L., Napierala, M., and M. Sridhavan, "Problem Statement: Overlays for Network Virtualization", draft-ietf-nvo3-overlay-problem-statement-00 (work in progress), September 2012. [I-D.kompella-nvo3-server2nve] Kompella, K., Rekhter, Y., and T. Morin, "Using Signaling to Simplify Network Virtualization Provisioning", draft-kompella-nvo3-server2nve-00 (work in progress), July 2012. [I-D.lasserre-nvo3-framework] Lasserre, M., Balus, F., Morin, T., Bitar, N., and Y. Rekhter, "Framework for DC Network Virtualization", draft-lasserre-nvo3-framework-03 (work in progress), July 2012. [I-D.mahalingam-dutt-dcops-vxlan] Sridhar, T., Bursell, M., Kreeger, L., Dutt, D., Wright, C., Mahalingam, M., Duda, K., and P. Agarwal, "VXLAN: A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks", draft-mahalingam-dutt-dcops-vxlan-01 (work in progress), February 2012. [I-D.smith-lisp-layer2] Smith, M. and D. Dutt, "Layer 2 (L2) LISP Encapsulation Format", draft-smith-lisp-layer2-00 (work in progress), March 2011. [I-D.sridharan-virtualization-nvgre] Sridhavan, M., Duda, K., Ganga, I., Greenberg, A., Lin, G., Pearson, M., Thaler, P., Tumuluri, C., and Y. Wang, "NVGRE: Network Virtualization using Generic Routing Encapsulation", draft-sridharan-virtualization-nvgre-00 (work in progress), September 2011. Maino, et al. Expires April 25, 2013 [Page 20] Internet-Draft LISP Control Plane for NVO3 October 2012 Authors' Addresses Fabio Maino Cisco Systems 170 Tasman Drive San Jose, California 95134 USA Email: fmaino@cisco.com Vina Ermagan Cisco Systems 170 Tasman Drive San Jose, California 95134 USA Email: vermagan@cisco.com Dino Farinacci Cisco Systems 170 Tasman Drive San Jose, California 95134 USA Email: dino@cisco.com Michael Smith Insieme Networks California USA Email: michsmit@insiemenetworks.com Maino, et al. Expires April 25, 2013 [Page 21]