| Network Working Group | F.M. Maino |
| Internet-Draft | V.E. Ermagan |
| Intended status: Experimental | D.F. Farinacci |
| Expires: March 21, 2013 | Cisco Systems |
| M.S. Smith | |
| Insieme Networks | |
| September 19, 2012 |
LISP Control Plane for Network Virtualization Overlays
draft-maino-nvo3-lisp-cp-01
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.
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].
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 March 21, 2013.
Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http:/⁠/⁠trustee.ietf.org/⁠license-⁠info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
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 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.
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].
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 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 <IID,MAC> 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.
,---------.
,' `.
(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=
<IID1,MAC_W> <IID2,MAC_X> <IID1,MAC_Y> <IID1,MAC_Z>
Figure 1: Example of L2 NVO3 Services
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 [I-D.mahalingam-dutt-dcops-vxlan].
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.
Upon notification of end system network attach, that includes the EID=<IID,MAC> 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].
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).
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.
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 = <IID1,IP_Y,MAC_Y>.
,---------.
,' `.
(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=
<IID1,IP_W, <IID2,IP_X, <IID1,IP_Y, <IID1,IP_Z,
MAC_W> MAC_X> MAC_Y> MAC_Z>
Figure 2: Example of L3 NVO3 Services
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.
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.
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 | .
. +--------+ .
......................
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.
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.
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.
This section describes the functional components of a LISP NVE as defined in Section 3 of [I-D.lasserre-nvo3-framework].
The generic reference model for NVE is depicted in Section 3.1 of [I-D.lasserre-nvo3-framework].
+------- 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
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).
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.
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.
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).
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.
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 explosive ARP handling.
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].
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.
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.
Packet replication in the underlay network to support broadcast, unknown unicast and multicast overlay services can be done by:
[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 [RFC3618], and PIM-SSM [RFC4607].
[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.
This document has no IANA implications
The authors want to thank Victor Moreno and Paul Quinn for the early review, insightful comments and suggestions.
| [RFC2119] | Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. |
| [RFC4601] | Fenner, B., Handley, M., Holbrook, H. and I. Kouvelas, "Protocol Independent Multicast - Sparse Mode (PIM-SM): Protocol Specification (Revised)", RFC 4601, August 2006. |
| [RFC3618] | Fenner, B. and D. Meyer, "Multicast Source Discovery Protocol (MSDP)", RFC 3618, October 2003. |
| [RFC4607] | Holbrook, H. and B. Cain, "Source-Specific Multicast for IP", RFC 4607, August 2006. |
| [I-D.ietf-lisp] | Farinacci, D, Fuller, V, Meyer, D and D Lewis, "Locator/ID Separation Protocol (LISP)", Internet-Draft draft-ietf-lisp-23, May 2012. |
| [I-D.fuller-lisp-ddt] | Fuller, V and D Lewis, "LISP Delegated Database Tree", Internet-Draft draft-fuller-lisp-ddt-01, March 2012. |
| [I-D.ietf-lisp-ms] | Fuller, V and D Farinacci, "LISP Map Server Interface", Internet-Draft draft-ietf-lisp-ms-14, December 2011. |
| [I-D.ietf-lisp-lcaf] | Farinacci, D, Meyer, D and J Snijders, "LISP Canonical Address Format (LCAF)", Internet-Draft draft-ietf-lisp-lcaf-00, August 2012. |
| [I-D.ietf-lisp-sec] | Maino, F, Ermagan, V, Cabellos-Aparicio, A, Saucez, D and O Bonaventure, "LISP-Security (LISP-SEC)", Internet-Draft draft-ietf-lisp-sec-02, March 2012. |
| [I-D.smith-lisp-layer2] | Smith, M and D Dutt, "Layer 2 (L2) LISP Encapsulation Format", Internet-Draft draft-smith-lisp-layer2-00, March 2011. |
| [I-D.ietf-lisp-alt] | Fuller, V, Farinacci, D, Meyer, D and D Lewis, "LISP Alternative Topology (LISP+ALT)", Internet-Draft draft-ietf-lisp-alt-10, December 2011. |
| [I-D.ietf-lisp-multicast] | Farinacci, D, Meyer, D, Zwiebel, J and S Venaas, "LISP for Multicast Environments", Internet-Draft draft-ietf-lisp-multicast-14, February 2012. |
| [I-D.farinacci-lisp-te] | Farinacci, D, Lahiri, P and M Kowal, "LISP Traffic Engineering Use-Cases", Internet-Draft draft-farinacci-lisp-te-00, March 2012. |
| [I-D.ietf-lisp-interworking] | Lewis, D, Meyer, D, Farinacci, D and V Fuller, "Interworking LISP with IPv4 and IPv6", Internet-Draft draft-ietf-lisp-interworking-06, March 2012. |
| [I-D.farinacci-lisp-mr-signaling] | Farinacci, D and M Napierala, "LISP Control-Plane Multicast Signaling", Internet-Draft draft-farinacci-lisp-mr-signaling-00, July 2012. |
| [I-D.lasserre-nvo3-framework] | Lasserre, M, Balus, F, Morin, T, Bitar, N and Y Rekhter, "Framework for DC Network Virtualization", Internet-Draft draft-lasserre-nvo3-framework-03, July 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", Internet-Draft draft-ietf-nvo3-overlay-problem-statement-00, September 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", Internet-Draft draft-mahalingam-dutt-dcops-vxlan-01, February 2012. |
| [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", Internet-Draft draft-sridharan-virtualization-nvgre-00, September 2011. |