L2VPN Workgroup A. Sajassi (Editor) INTERNET-DRAFT Cisco Intended Status: Standards Track J. Drake (Editor) Juniper Nabil Bitar Verizon Aldrin Isaac Juniper James Uttaro AT&T W. Henderickx Alcatel-Lucent Expires: April 19, 2016 October 19, 2015 A Network Virtualization Overlay Solution using EVPN draft-ietf-bess-evpn-overlay-02 Abstract This document describes how Ethernet VPN (EVPN) [RFC7432] can be used as an Network Virtualization Overlay (NVO) solution and explores the various tunnel encapsulation options over IP and their impact on the EVPN control-plane and procedures. In particular, the following encapsulation options are analyzed: VXLAN, NVGRE, and MPLS over GRE. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Sajassi-Drake et al. Expires April 19, 2016 [Page 1] INTERNET DRAFT EVPN Overlay October 19, 2015 Copyright and License Notice 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. Table of Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 2 Specification of Requirements . . . . . . . . . . . . . . . . . 5 3 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4 EVPN Features . . . . . . . . . . . . . . . . . . . . . . . . . 6 5 Encapsulation Options for EVPN Overlays . . . . . . . . . . . . 7 5.1 VXLAN/NVGRE Encapsulation . . . . . . . . . . . . . . . . . 7 5.1.1 Virtual Identifiers Scope . . . . . . . . . . . . . . . 8 5.1.1.1 Data Center Interconnect with Gateway . . . . . . . 8 5.1.1.2 Data Center Interconnect without Gateway . . . . . . 9 5.1.2 Virtual Identifiers to EVI Mapping . . . . . . . . . . . 9 5.1.2.1 Auto Derivation of RT . . . . . . . . . . . . . . . 10 5.1.3 Constructing EVPN BGP Routes . . . . . . . . . . . . . 11 5.2 MPLS over GRE . . . . . . . . . . . . . . . . . . . . . . . 13 6 EVPN with Multiple Data Plane Encapsulations . . . . . . . . . 13 7 NVE Residing in Hypervisor . . . . . . . . . . . . . . . . . . 14 7.1 Impact on EVPN BGP Routes & Attributes for VXLAN/NVGRE Encapsulation . . . . . . . . . . . . . . . . . . . . . . . 14 7.2 Impact on EVPN Procedures for VXLAN/NVGRE Encapsulation . . 15 8 NVE Residing in ToR Switch . . . . . . . . . . . . . . . . . . 15 8.1 EVPN Multi-Homing Features . . . . . . . . . . . . . . . . 16 8.1.1 Multi-homed Ethernet Segment Auto-Discovery . . . . . . 16 8.1.2 Fast Convergence and Mass Withdraw . . . . . . . . . . . 16 8.1.3 Split-Horizon . . . . . . . . . . . . . . . . . . . . . 16 8.1.4 Aliasing and Backup-Path . . . . . . . . . . . . . . . . 17 8.1.5 DF Election . . . . . . . . . . . . . . . . . . . . . . 17 8.2 Impact on EVPN BGP Routes & Attributes . . . . . . . . . . . 18 8.3 Impact on EVPN Procedures . . . . . . . . . . . . . . . . . 18 8.3.1 Split Horizon . . . . . . . . . . . . . . . . . . . . . 19 8.3.2 Aliasing and Backup-Path . . . . . . . . . . . . . . . . 19 Sajassi-Drake et al. Expires April 19, 2016 [Page 2] INTERNET DRAFT EVPN Overlay October 19, 2015 9 Support for Multicast . . . . . . . . . . . . . . . . . . . . . 19 10 Data Center Interconnections - DCI . . . . . . . . . . . . . . 20 10.1 DCI using GWs . . . . . . . . . . . . . . . . . . . . . . . 20 10.2 DCI using ASBRs . . . . . . . . . . . . . . . . . . . . . . 21 10.2.1 ASBR Functionality with NVEs in Hypervisors . . . . . . 22 10.2.2 ASBR Functionality with NVEs in TORs . . . . . . . . . 22 11 Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 24 12 Security Considerations . . . . . . . . . . . . . . . . . . . 24 13 IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25 14 References . . . . . . . . . . . . . . . . . . . . . . . . . . 25 14.1 Normative References . . . . . . . . . . . . . . . . . . . 25 14.2 Informative References . . . . . . . . . . . . . . . . . . 25 Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 26 Sajassi-Drake et al. Expires April 19, 2016 [Page 3] INTERNET DRAFT EVPN Overlay October 19, 2015 1 Introduction In the context of this document, a Network Virtualization Overlay (NVO) is a solution to address the requirements of a multi-tenant data center, especially one with virtualized hosts, e.g., Virtual Machines (VMs). The key requirements of such a solution, as described in [Problem-Statement], are: - Isolation of network traffic per tenant - Support for a large number of tenants (tens or hundreds of thousands) - Extending L2 connectivity among different VMs belonging to a given tenant segment (subnet) across different PODs within a data center or between different data centers - Allowing a given VM to move between different physical points of attachment within a given L2 segment The underlay network for NVO solutions is assumed to provide IP connectivity between NVO endpoints (NVEs). This document describes how Ethernet VPN (EVPN) can be used as an NVO solution and explores applicability of EVPN functions and procedures. In particular, it describes the various tunnel encapsulation options for EVPN over IP, and their impact on the EVPN control-plane and procedures for two main scenarios: a) when the NVE resides in the hypervisor, and b) when the NVE resides in a Top of Rack (ToR) device Note that the use of EVPN as an NVO solution does not necessarily mandate that the BGP control-plane be running on the NVE. For such scenarios, it is still possible to leverage the EVPN solution by using XMPP, or alternative mechanisms, to extend the control-plane to the NVE as discussed in [L3VPN-ENDSYSTEMS]. The possible encapsulation options for EVPN overlays that are analyzed in this document are: - VXLAN and NVGRE - MPLS over GRE Before getting into the description of the different encapsulation options for EVPN over IP, it is important to highlight the EVPN solution's main features, how those features are currently supported, Sajassi-Drake et al. Expires April 19, 2016 [Page 4] INTERNET DRAFT EVPN Overlay October 19, 2015 and any impact that the encapsulation has on those features. 2 Specification of 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]. 3 Terminology NVO: Network Virtualization Overlay NVE: Network Virtualization Endpoint VNI: Virtual Network Identifier (for VXLAN) VSID: Virtual Subnet Identifier (for NVGRE) EVPN: Ethernet VPN EVI: An EVPN instance spanning the Provider Edge (PE) devices participating in that EVPN. MAC-VRF: A Virtual Routing and Forwarding table for Media Access Control (MAC) addresses on a PE. Ethernet Segment (ES): When a customer site (device or network) is connected to one or more PEs via a set of Ethernet links, then that set of links is referred to as an 'Ethernet segment'. Ethernet Segment Identifier (ESI): A unique non-zero identifier that identifies an Ethernet segment is called an 'Ethernet Segment Identifier'. Ethernet Tag: An Ethernet tag identifies a particular broadcast domain, e.g., a VLAN. An EVPN instance consists of one or more broadcast domains. PE: Provider Edge device. Single-Active Redundancy Mode: When only a single PE, among all the PEs attached to an Ethernet segment, is allowed to forward traffic to/from that Ethernet segment for a given VLAN, then the Ethernet segment is defined to be operating in Single-Active redundancy mode. All-Active Redundancy Mode: When all PEs attached to an Ethernet Sajassi-Drake et al. Expires April 19, 2016 [Page 5] INTERNET DRAFT EVPN Overlay October 19, 2015 segment are allowed to forward known unicast traffic to/from that Ethernet segment for a given VLAN, then the Ethernet segment is defined to be operating in All-Active redundancy mode. 4 EVPN Features EVPN was originally designed to support the requirements detailed in [RFC7209] and therefore has the following attributes which directly address control plane scaling and ease of deployment issues. 1) Control plane traffic is distributed with BGP and Broadcast and Multicast traffic is sent using a shared multicast tree or with ingress replication. 2) Control plane learning is used for MAC (and IP) addresses instead of data plane learning. The latter requires the flooding of unknown unicast and ARP frames; whereas, the former does not require any flooding. 3) Route Reflector is used to reduce a full mesh of BGP sessions among PE devices to a single BGP session between a PE and the RR. Furthermore, RR hierarchy can be leveraged to scale the number of BGP routes on the RR. 4) Auto-discovery via BGP is used to discover PE devices participating in a given VPN, PE devices participating in a given redundancy group, tunnel encapsulation types, multicast tunnel type, multicast members, etc. 5) All-Active multihoming is used. This allows a given customer device (CE) to have multiple links to multiple PEs, and traffic to/from that CE fully utilizes all of these links. This set of links is termed an Ethernet Segment (ES). 6) When a link between a CE and a PE fails, the PEs for that EVI are notified of the failure via the withdrawal of a single EVPN route. This allows those PEs to remove the withdrawing PE as a next hop for every MAC address associated with the failed link. This is termed 'mass withdrawal'. 7) BGP route filtering and constrained route distribution are leveraged to ensure that the control plane traffic for a given EVI is only distributed to the PEs in that EVI. 8) When a 802.1Q interface is used between a CE and a PE, each of the VLAN ID (VID) on that interface can be mapped onto a bridge table (for upto 4094 such bridge tables). All these bridge tables may be Sajassi-Drake et al. Expires April 19, 2016 [Page 6] INTERNET DRAFT EVPN Overlay October 19, 2015 mapped onto a single MAC-VRF (in case of VLAN-aware bundle service). 9) VM Mobility mechanisms ensure that all PEs in a given EVI know the ES with which a given VM, as identified by its MAC and IP addresses, is currently associated. 10) Route Targets are used to allow the operator (or customer) to define a spectrum of logical network topologies including mesh, hub & spoke, and extranets (e.g., a VPN whose sites are owned by different enterprises), without the need for proprietary software or the aid of other virtual or physical devices. 11) Because the design goal for NVO is millions of instances per common physical infrastructure, the scaling properties of the control plane for NVO are extremely important. EVPN and the extensions described herein, are designed with this level of scalability in mind. 5 Encapsulation Options for EVPN Overlays 5.1 VXLAN/NVGRE Encapsulation Both VXLAN and NVGRE are examples of technologies that provide a data plane encapsulation which is used to transport a packet over the common physical IP infrastructure between VXLAN Tunnel End Points (VTEPs) in VXLAN network and Network Virtualization Endpoints (NVEs) in NVGRE network. Both of these technologies include the identifier of the specific NVO instance, Virtual Network Identifier (VNI) in VXLAN and Virtual Subnet Identifier (VSID) in NVGRE, in each packet. Note that a Provider Edge (PE) is equivalent to a VTEP/NVE. VXLAN encapsulation is based on UDP, with an 8-byte header following the UDP header. VXLAN provides a 24-bit VNI, which typically provides a one-to-one mapping to the tenant VLAN ID, as described in [RFC7348]. In this scenario, the ingress VTEP does not include an inner VLAN tag on the encapsulated frame, and the egress VTEP discards the frames with an inner VLAN tag. This mode of operation in [RFC7348] maps to VLAN Based Service in [RFC7432], where a tenant VLAN ID gets mapped to an EVPN instance (EVI). VXLAN also provides an option of including an inner VLAN tag in the encapsulated frame, if explicitly configured at the VTEP. This mode of operation can map to VLAN Bundle Service in [RFC7432] because all the tenant's tagged frames map to a single bridge table / MAC-VRF, and the inner VLAN tag is not used for lookup by the disposition PE Sajassi-Drake et al. Expires April 19, 2016 [Page 7] INTERNET DRAFT EVPN Overlay October 19, 2015 when performing VXLAN decapsulation as described in section 6 of [RFC7348]. [NVGRE] encapsulation is based on [GRE] and it mandates the inclusion of the optional GRE Key field which carries the VSID. There is a one- to-one mapping between the VSID and the tenant VLAN ID, as described in [NVGRE] and the inclusion of an inner VLAN tag is prohibited. This mode of operation in [NVGRE] maps to VLAN Based Service in [RFC7432]. As described in the next section there is no change to the encoding of EVPN routes to support VXLAN or NVGRE encapsulation except for the use of BGP Encapsulation extended community. However, there is potential impact to the EVPN procedures depending on where the NVE is located (i.e., in hypervisor or TOR) and whether multi-homing capabilities are required. 5.1.1 Virtual Identifiers Scope Although VNI or VSID are defined as 24-bit globally unique values, there are scenarios in which it is desirable to use a locally significant value for VNI or VSID, especially in the context of data center interconnect: 5.1.1.1 Data Center Interconnect with Gateway In the case where NVEs in different data centers need to be interconnected, and the NVEs need to use VNIs or VSIDs as a globally unique identifiers within a data center, then a Gateway needs to be employed at the edge of the data center network. This is because the Gateway will provide the functionality of translating the VNI or VSID when crossing network boundaries, which may align with operator span of control boundaries. As an example, consider the network of Figure 1 below. Assume there are three network operators: one for each of the DC1, DC2 and WAN networks. The Gateways at the edge of the data centers are responsible for translating the VNIs / VSIDs between the values used in each of the data center networks and the values used in the WAN. Sajassi-Drake et al. Expires April 19, 2016 [Page 8] INTERNET DRAFT EVPN Overlay October 19, 2015 +--------------+ | | +---------+ | WAN | +---------+ +----+ | +---+ +----+ +----+ +---+ | +----+ |NVE1|--| | | |WAN | |WAN | | | |--|NVE3| +----+ |IP |GW |--|Edge| |Edge|--|GW | IP | +----+ +----+ |Fabric +---+ +----+ +----+ +---+ Fabric | +----+ |NVE2|--| | | | | |--|NVE4| +----+ +---------+ +--------------+ +---------+ +----+ |<------ DC 1 ------> <------ DC2 ------>| Figure 1: Data Center Interconnect with Gateway 5.1.1.2 Data Center Interconnect without Gateway In the case where NVEs in different data centers need to be interconnected, and the NVEs need to use locally assigned VNIs or VSIDs (e.g., as MPLS labels), then there may be no need to employ Gateways at the edge of the data center network. More specifically, the VNI or VSID value that is used by the transmitting NVE is allocated by the NVE that is receiving the traffic (in other words, this is a "downstream assigned" MPLS label). This allows the VNI or VSID space to be decoupled between different data center networks without the need for a dedicated Gateway at the edge of the data centers. +--------------+ | | +---------+ | WAN | +---------+ +----+ | | +----+ +----+ | | +----+ |NVE1|--| | |WAN | |WAN | | |--|NVE3| +----+ |IP Fabric|---|Edge| |Edge|--|IP Fabric| +----+ +----+ | | +----+ +----+ | | +----+ |NVE2|--| | | | | |--|NVE4| +----+ +---------+ +--------------+ +---------+ +----+ |<------ DC 1 -----> <---- DC2 ------>| Figure 2: Data Center Interconnect without Gateway 5.1.2 Virtual Identifiers to EVI Mapping When the EVPN control plane is used in conjunction with VXLAN or NVGRE, two options for mapping the VXLAN VNI or NVGRE VSID to an EVI are possible: Sajassi-Drake et al. Expires April 19, 2016 [Page 9] INTERNET DRAFT EVPN Overlay October 19, 2015 1. Option 1: Single Subnet per EVI In this option, a single subnet represented by a VNI or VSID is mapped to a unique EVI. This corresponds to the VLAN Based service in [RFC7432], where a tenant VLAN ID gets mapped to an EVPN instance (EVI). As such, a BGP RD and RT is needed per VNI / VSID on every VTEP. The advantage of this model is that it allows the BGP RT constraint mechanisms to be used in order to limit the propagation and import of routes to only the VTEPs that are interested in a given VNI or VSID. The disadvantage of this model may be the provisioning overhead if RD and RT are not derived automatically from VNI or VSID. In this option, the MAC-VRF table is identified by the RT in the control plane and by the VNI or VSID in the data-plane. In this option, the specific the MAC-VRF table corresponds to only a single bridge table. 2. Option 2: Multiple Subnets per EVI In this option, multiple subnets each represented by a unique VNI or VSID are mapped to a single EVI. For example, if a tenant has multiple segments/subnets each represented by a VNI or VSID, then all the VNIs (or VSIDs) for that tenant are mapped to a single EVI - e.g., the EVI in this case represents the tenant and not a subnet . This corresponds to the VLAN-Aware Bundle service in [RFC7432]. The advantage of this model is that it doesn't require the provisioning of RD/RT per VNI or VSID. However, this is a moot point if option 1 with auto-derivation is used. The disadvantage of this model is that routes would be imported by VTEPs that may not be interested in a given VNI or VSID. In this option the MAC-VRF table is identified by the RT in the control plane and a specific bridge table for that MAC-VRF is identified by the in the control plane. In this option, the VNI/VSID in the data-plane is sufficient to identify a specific bridge table - e.g., no need to do a lookup based on VNI/VSID and Ethernet Tag ID fields to identify a bridge table. 5.1.2.1 Auto Derivation of RT When the option of a single VNI or VSID per EVI is used, it is important to auto-derive RT for EVPN BGP routes in order to simplify configuration for data center operations. RD can be derived easily as described in [RFC7432] and RT can be auto-derived as described next. Sajassi-Drake et al. Expires April 19, 2016 [Page 10] INTERNET DRAFT EVPN Overlay October 19, 2015 Since a gateway PE as depicted in figure-1 participates in both the DCN and WAN BGP sessions, it is important that when RT values are auto-derived for VNIs (or VSIDs), there is no conflict in RT spaces between DCN and WAN networks assuming that both are operating within the same AS. Also, there can be scenarios where both VXLAN and NVGRE encapsulations may be needed within the same DCN and their corresponding VNIs and VSIDs are administered independently which means VNI and VSID spaces can overlap. In order to ensure that no such conflict in RT spaces arises, RT values for DCNs are auto- derived as follow: 0 1 2 3 4 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 0 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+---+ | AS # |A| TYPE| D-ID |Service Instance ID| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+---+ - 2 bytes of global admin field of the RT is set to the AS number. - Three least significant bytes of the local admin field of the RT is set to the VNI or VSID, I-SID, or VID. The most significant bit of the local admin field of the RT is set as follow: 0: auto-derived 1: manually-derived - The next 3 bits of the most significant byte of the local admin field of the RT identifies the space in which the other 3 bytes are defined. The following spaces are defined: 0 : VID 1 : VXLAN 2 : NVGRE 3 : I-SID 4 : EVI 5 : dual-VID - The remaining 4 bits of the most significant byte of the local admin field of the RT identifies the domain-id. The default value of domain-id is zero indicating that only a single numbering space exist for a given technology. However, if there are more than one number space exist for a given technology (e.g., overlapping VXLAN spaces), then each of the number spaces need to be identify by their corresponding domain-id starting from 1. 5.1.3 Constructing EVPN BGP Routes Sajassi-Drake et al. Expires April 19, 2016 [Page 11] INTERNET DRAFT EVPN Overlay October 19, 2015 In EVPN, an MPLS label is distributed by the egress PE via the EVPN control plane and is placed in the MPLS header of a given packet by the ingress PE. This label is used upon receipt of that packet by the egress PE for disposition of that packet. This is very similar to the use of the VNI or VSID by the egress VTEP or NVE, respectively, with the difference being that an MPLS label has local significance while a VNI or VSID typically has global significance. Accordingly, and specifically to support the option of locally assigned VNIs, the MPLS label field in the MAC Advertisement, Ethernet AD per EVI, and Inclusive Multicast Ethernet Tag routes is used to carry the VNI or VSID. For the balance of this memo, the MPLS label field will be referred to as the VNI/VSID field. The VNI/VSID field is used for both local and global VNIs/VSIDs, and for either case the entire 24- bit field is used to encode the VNI/VSID value. For the VLAN-based service (a single VNI per MAC-VRF), the Ethernet Tag field in the MAC/IP Advertisement, Ethernet AD per EVI, and Inclusive Multicast route MUST be set to zero just as in the VLAN Based service in [RFC7432]. For the VLAN-aware bundle service (multiple VNIs per MAC-VRF with each VNI associated with its own bridge table), the Ethernet Tag field in the MAC Advertisement, Ethernet AD per EVI, and Inclusive Multicast route MUST identify a bridge table within a MAC-VRF and the set of Ethernet Tags for that EVI needs to be configured consistently on all PEs within that EVI. For local VNIs, the value advertised in the Ethernet Tag field MUST be set to a VID just as in the VLAN-aware bundle service in [RFC7432]. Such setting must be done consistently on all PE devices participating in that EVI within a given domain. For global VNIs, the value advertised in the Ethernet Tag field SHOULD be set to a VNI as long as it matches the existing semantics of the Ethernet Tag, i.e., it identifies a bridge table within a MAC- VRF and the set of VNIs are configured consistently on each PE in that EVI. In order to indicate that which type of data plane encapsulation (i.e., VXLAN, NVGRE, MPLS, or MPLS in GRE) is to be used, the BGP Encapsulation extended community defined in [RFC5512] is included with all EVPN routes (i.e. MAC Advertisement, Ethernet AD per EVI, Ethernet AD per ESI, Inclusive Multicast Ethernet Tag, and Ethernet Segment) advertised by an egress PE. Five new values have been assigned by IANA to extend the list of encapsulation types defined in [RFC5512]: + 8 - VXLAN Encapsulation + 9 - NVGRE Encapsulation + 10 - MPLS Encapsulation Sajassi-Drake et al. Expires April 19, 2016 [Page 12] INTERNET DRAFT EVPN Overlay October 19, 2015 + 11 - MPLS in GRE Encapsulation + 12 - VXLAN GPE Encapsulation If the BGP Encapsulation extended community is not present, then the default MPLS encapsulation or a statically configured encapsulation is assumed. The Ethernet Segment and Ethernet AD per ESI routes MAY be advertised with multiple encapsulation types as long as they use the same EVPN multi-homing procedures - e.g., the mix of VXLAN and NVGRE encapsulation types is a valid one but not the mix of VXLAN and MPLS encapsulation types. The Next Hop field of the MP_REACH_NLRI attribute of the route MUST be set to the IPv4 or IPv6 address of the NVE. The remaining fields in each route are set as per [RFC7432]. 5.2 MPLS over GRE The EVPN data-plane is modeled as an EVPN MPLS client layer sitting over an MPLS PSN tunnel. Some of the EVPN functions (split-horizon, aliasing, and backup-path) are tied to the MPLS client layer. If MPLS over GRE encapsulation is used, then the EVPN MPLS client layer can be carried over an IP PSN tunnel transparently. Therefore, there is no impact to the EVPN procedures and associated data-plane operation. The existing standards for MPLS over GRE encapsulation as defined by [RFC4023] can be used for this purpose; however, when it is used in conjunction with EVPN the key field SHOULD be present, and SHOULD be used to provide a 32-bit entropy field. The Checksum and Sequence Number fields are not needed and their corresponding C and S bits MUST be set to zero. 6 EVPN with Multiple Data Plane Encapsulations The use of the BGP Encapsulation extended community allows each PE in a given EVI to know each of the encapsulations supported by each of the other PEs in that EVI. I.e., each of the PEs in a given EVI may support multiple data plane encapsulations. An ingress PE can send a frame to an egress PE only if the set of encapsulations advertised by the egress PE in the subject MAC/IP Advertisement or per EVI Ethernet AD route, forms a non-empty intersection with the set of encapsulations supported by the ingress PE, and it is at the discretion of the ingress PE which encapsulation to choose from this intersection. (As noted in section 5.1.3, if the BGP Encapsulation Sajassi-Drake et al. Expires April 19, 2016 [Page 13] INTERNET DRAFT EVPN Overlay October 19, 2015 extended community is not present, then the default MPLS encapsulation or a statically configured encapsulation is assumed.) An ingress node that uses shared multicast trees for sending broadcast or multicast frames MUST maintain distinct trees for each different encapsulation type. It is the responsibility of the operator of a given EVI to ensure that all of the PEs in that EVI support at least one common encapsulation. If this condition is violated, it could result in service disruption or failure. The use of the BGP Encapsulation extended community provides a method to detect when this condition is violated but the actions to be taken are at the discretion of the operator and are outside the scope of this document. 7 NVE Residing in Hypervisor When a PE and its CEs are co-located in the same physical device, e.g., when the PE resides in a server and the CEs are its VMs, the links between them are virtual and they typically share fate; i.e., the subject CEs are typically not multi-homed or if they are multi- homed, the multi-homing is a purely local matter to the server hosting the VM, and need not be "visible" to any other PEs, and thus does not require any specific protocol mechanisms. The most common case of this is when the NVE resides in the hypervisor. In the sub-sections that follow, we will discuss the impact on EVPN procedures for the case when the NVE resides on the hypervisor and the VXLAN or NVGRE encapsulation is used. 7.1 Impact on EVPN BGP Routes & Attributes for VXLAN/NVGRE Encapsulation In the scenario where all data centers are under a single administrative domain, and there is a single global VNI/VSID space, the RD MAY be set to zero in the EVPN routes. However, in the scenario where different groups of data centers are under different administrative domains, and these data centers are connected via one or more backbone core providers as described in [NOV3-Framework], the RD must be a unique value per EVI or per NVE as described in [RFC7432]. In other words, whenever there is more than one administrative domain for global VNI or VSID, then a non-zero RD MUST be used, or whenever the VNI or VSID value have local significance, then a non-zero RD MUST be used. It is recommend to use a non-zero RD at all time. When the NVEs reside on the hypervisor, the EVPN BGP routes and attributes associated with multi-homing are no longer required. This reduces the required routes and attributes to the following subset of Sajassi-Drake et al. Expires April 19, 2016 [Page 14] INTERNET DRAFT EVPN Overlay October 19, 2015 four out of the set of eight : - MAC Advertisement Route - Inclusive Multicast Ethernet Tag Route - MAC Mobility Extended Community - Default Gateway Extended Community However, as noted in section 8.6 of [RFC7432] in order to enable a single-homing ingress PE to take advantage of fast convergence, aliasing, and backup-path when interacting with multi-homed egress PEs attached to a given Ethernet segment, a single-homing ingress PE SHOULD be able to receive and process Ethernet AD per ES and Ethernet AD per EVI routes." 7.2 Impact on EVPN Procedures for VXLAN/NVGRE Encapsulation When the NVEs reside on the hypervisors, the EVPN procedures associated with multi-homing are no longer required. This limits the procedures on the NVE to the following subset of the EVPN procedures: 1. Local learning of MAC addresses received from the VMs per section 10.1 of [RFC7432]. 2. Advertising locally learned MAC addresses in BGP using the MAC Advertisement routes. 3. Performing remote learning using BGP per Section 10.2 of [RFC7432]. 4. Discovering other NVEs and constructing the multicast tunnels using the Inclusive Multicast Ethernet Tag routes. 5. Handling MAC address mobility events per the procedures of Section 16 in [RFC7432]. However, as noted in section 8.6 of [RFC7432] in order to enable a single-homing ingress PE to take advantage of fast convergence, aliasing, and back-up path when interacting with multi-homed egress PEs attached to a given Ethernet segment, a single-homing ingress PE SHOULD implement the ingress node processing of Ethernet AD per ES and Ethernet AD per EVI routes as defined in sections 8.2 Fast Convergence and 8.4 Aliasing and Backup-Path of [RFC7432]. 8 NVE Residing in ToR Switch In this section, we discuss the scenario where the NVEs reside in the Top of Rack (ToR) switches AND the servers (where VMs are residing) Sajassi-Drake et al. Expires April 19, 2016 [Page 15] INTERNET DRAFT EVPN Overlay October 19, 2015 are multi-homed to these ToR switches. The multi-homing may operate in All-Active or Single-Active redundancy mode. If the servers are single-homed to the ToR switches, then the scenario becomes similar to that where the NVE resides in the hypervisor, as discussed in Section 5, as far as the required EVPN functionality. [RFC7432] defines a set of BGP routes, attributes and procedures to support multi-homing. We first describe these functions and procedures, then discuss which of these are impacted by the encapsulation (such as VXLAN or NVGRE) and what modifications are required. 8.1 EVPN Multi-Homing Features In this section, we will recap the multi-homing features of EVPN to highlight the encapsulation dependencies. The section only describes the features and functions at a high-level. For more details, the reader is to refer to [RFC7432]. 8.1.1 Multi-homed Ethernet Segment Auto-Discovery EVPN NVEs (or PEs) connected to the same Ethernet Segment (e.g. the same server via LAG) can automatically discover each other with minimal to no configuration through the exchange of BGP routes. 8.1.2 Fast Convergence and Mass Withdraw EVPN defines a mechanism to efficiently and quickly signal, to remote NVEs, the need to update their forwarding tables upon the occurrence of a failure in connectivity to an Ethernet segment (e.g., a link or a port failure). This is done by having each NVE advertise an Ethernet A-D Route per Ethernet segment for each locally attached segment. Upon a failure in connectivity to the attached segment, the NVE withdraws the corresponding Ethernet A-D route. This triggers all NVEs that receive the withdrawal to update their next-hop adjacencies for all MAC addresses associated with the Ethernet segment in question. If no other NVE had advertised an Ethernet A-D route for the same segment, then the NVE that received the withdrawal simply invalidates the MAC entries for that segment. Otherwise, the NVE updates the next-hop adjacencies to point to the backup NVE(s). 8.1.3 Split-Horizon If a server is multi-homed to two or more NVEs on an Ethernet segment ES1 operating in all-active redundancy mode sends a multicast, broadcast or unknown unicast packet to a one of these NVEs, then it is important to ensure the packet is not looped back to the server via another NVE connected to this server. The filtering mechanism on Sajassi-Drake et al. Expires April 19, 2016 [Page 16] INTERNET DRAFT EVPN Overlay October 19, 2015 the NVE to prevent such loop and packet duplication is called "split horizon filtering'. 8.1.4 Aliasing and Backup-Path In the case where a station is multi-homed to multiple NVEs, it is possible that only a single NVE learns a set of the MAC addresses associated with traffic transmitted by the station. This leads to a situation where remote NVEs receive MAC advertisement routes, for these addresses, from a single NVE even though multiple NVEs are connected to the multi-homed station. As a result, the remote NVEs are not able to effectively load-balance traffic among the NVEs connected to the multi-homed Ethernet segment. This could be the case, for e.g. when the NVEs perform data-path learning on the access, and the load-balancing function on the station hashes traffic from a given source MAC address to a single NVE. Another scenario where this occurs is when the NVEs rely on control plane learning on the access (e.g. using ARP), since ARP traffic will be hashed to a single link in the LAG. To alleviate this issue, EVPN introduces the concept of Aliasing. This refers to the ability of an NVE to signal that it has reachability to a given locally attached Ethernet segment, even when it has learnt no MAC addresses from that segment. The Ethernet A-D route per EVI is used to that end. Remote NVEs which receive MAC advertisement routes with non-zero ESI SHOULD consider the MAC address as reachable via all NVEs that advertise reachability to the relevant Segment using Ethernet A-D routes with the same ESI and with the Single-Active flag reset. Backup-Path is a closely related function, albeit it applies to the case where the redundancy mode is Single-Active. In this case, the NVE signals that it has reachability to a given locally attached Ethernet Segment using the Ethernet A-D route as well. Remote NVEs which receive the MAC advertisement routes, with non-zero ESI, SHOULD consider the MAC address as reachable via the advertising NVE. Furthermore, the remote NVEs SHOULD install a Backup-Path, for said MAC, to the NVE which had advertised reachability to the relevant Segment using an Ethernet A-D route with the same ESI and with the Single-Active flag set. 8.1.5 DF Election If a CE is multi-homed to two or more NVEs on an Ethernet segment operating in all-active redundancy mode, then for a given EVI only one of these NVEs, termed the Designated Forwarder (DF) is Sajassi-Drake et al. Expires April 19, 2016 [Page 17] INTERNET DRAFT EVPN Overlay October 19, 2015 responsible for sending it broadcast, multicast, and, if configured for that EVI, unknown unicast frames. This is required in order to prevent duplicate delivery of multi- destination frames to a multi-homed host or VM, in case of all-active redundancy. In NVEs where .1Q tagged frames are received from hosts, the DF election is performed on host VLAN IDs (VIDs). It is assumed that for a given Ethernet Segment, VIDs are unique and consistent (e.g., no duplicate VIDs exist). In GWs where VxLAN encapsulated frames are received, the DF election is performed on VNIs. Again, it is assumed that for a given Ethernet Segment, VNIs are unique and consistent (e.g., no duplicate VNIs exist). 8.2 Impact on EVPN BGP Routes & Attributes Since multi-homing is supported in this scenario, then the entire set of BGP routes and attributes defined in [RFC7432] are used. As discussed in Section 3.1.3, the VSID or VNI is carried in the VNI/VSID field in the MAC Advertisement, Ethernet AD per EVI, and Inclusive Multicast Ethernet Tag routes. 8.3 Impact on EVPN Procedures Two cases need to be examined here, depending on whether the NVEs are operating in Active/Standby or in All-Active redundancy. First, lets consider the case of Active/Standby redundancy, where the hosts are multi-homed to a set of NVEs, however, only a single NVE is active at a given point of time for a given VNI or VSID. In this case, the split-horizon and the aliasing functions are not required but other functions such as multi-homed Ethernet segment auto- discovery, fast convergence and mass withdraw, backup path, and DF election are required. Second, let's consider the case of All-Active redundancy. In this case, out of the EVPN multi-homing features listed in section 8.1, the use of the VXLAN or NVGRE encapsulation impacts the split-horizon and aliasing features, since those two rely on the MPLS client layer. Given that this MPLS client layer is absent with these types of encapsulations, alternative procedures and mechanisms are needed to provide the required functions. Those are discussed in detail next. Sajassi-Drake et al. Expires April 19, 2016 [Page 18] INTERNET DRAFT EVPN Overlay October 19, 2015 8.3.1 Split Horizon In EVPN, an MPLS label is used for split-horizon filtering to support active/active multi-homing where an ingress NVE adds a label corresponding to the site of origin (aka ESI Label) when encapsulating the packet. The egress NVE checks the ESI label when attempting to forward a multi-destination frame out an interface, and if the label corresponds to the same site identifier (ESI) associated with that interface, the packet gets dropped. This prevents the occurrence of forwarding loops. Since the VXLAN or NVGRE encapsulation does not include this ESI label, other means of performing the split-horizon filtering function MUST be devised. The following approach is recommended for split- horizon filtering when VXLAN or NVGRE encapsulation is used. Every NVE track the IP address(es) associated with the other NVE(s) with which it has shared multi-homed Ethernet Segments. When the NVE receives a multi-destination frame from the overlay network, it examines the source IP address in the tunnel header (which corresponds to the ingress NVE) and filters out the frame on all local interfaces connected to Ethernet Segments that are shared with the ingress NVE. With this approach, it is required that the ingress NVE performs replication locally to all directly attached Ethernet Segments (regardless of the DF Election state) for all flooded traffic ingress from the access interfaces (i.e. from the hosts). This approach is referred to as "Local Bias", and has the advantage that only a single IP address needs to be used per NVE for split- horizon filtering, as opposed to requiring an IP address per Ethernet Segment per NVE. In order to prevent unhealthy interactions between the split horizon procedures defined in [RFC7432] and the local bias procedures described in this document, a mix of MPLS over GRE encapsulations on the one hand and VXLAN/NVGRE encapsulations on the other on a given Ethernet Segment is prohibited. 8.3.2 Aliasing and Backup-Path The Aliasing and the Backup-Path procedures for VXLAN/NVGRE encapsulation is very similar to the ones for MPLS. In case of MPLS, two different Ethernet AD routes are used for this purpose. The one used for Aliasing has a VPN scope and carries a VPN label but the one used for Backup-Path has Ethernet segment scope and doesn't carry any VPN specific info (e.g., Ethernet Tag and MPLS label are set to zero). 9 Support for Multicast Sajassi-Drake et al. Expires April 19, 2016 [Page 19] INTERNET DRAFT EVPN Overlay October 19, 2015 The E-VPN Inclusive Multicast BGP route is used to discover the multicast tunnels among the endpoints associated with a given VXLAN VNI or NVGRE VSID. The Ethernet Tag field of this route is used to encode the VNI for VLXAN or VSID for NVGRE. The Originating router's IP address field is set to the NVE's IP address. This route is tagged with the PMSI Tunnel attribute, which is used to encode the type of multicast tunnel to be used as well as the multicast tunnel identifier. The tunnel encapsulation is encoded by adding the BGP Encapsulation extended community as per section 3.1.1. The following tunnel types as defined in [RFC6514] can be used in the PMSI tunnel attribute for VXLAN/NVGRE: + 3 - PIM-SSM Tree + 4 - PIM-SM Tree + 5 - BIDIR-PIM Tree + 6 - Ingress Replication Except for Ingress Replication, this multicast tunnel is used by the PE originating the route for sending multicast traffic to other PEs, and is used by PEs that receive this route for receiving the traffic originated by CEs connected to the PE that originated the route. In the scenario where the multicast tunnel is a tree, both the Inclusive as well as the Aggregate Inclusive variants may be used. In the former case, a multicast tree is dedicated to a VNI or VSID. Whereas, in the latter, a multicast tree is shared among multiple VNIs or VSIDs. This is done by having the NVEs advertise multiple Inclusive Multicast routes with different VNI or VSID encoded in the Ethernet Tag field, but with the same tunnel identifier encoded in the PMSI Tunnel attribute. 10 Data Center Interconnections - DCI For DCI, the following two main scenarios are considered when connecting data centers running evpn-overlay (as described here) over MPLS/IP core network: - Scenario 1: DCI using GWs - Scenario 2: DCI using ASBRs The following two subsections describe the operations for each of these scenarios. 10.1 DCI using GWs This is the typical scenario for interconnecting data centers over WAN. In this scenario, EVPN routes are terminated and processed in Sajassi-Drake et al. Expires April 19, 2016 [Page 20] INTERNET DRAFT EVPN Overlay October 19, 2015 each GW and MAC/IP routes are always re-advertised from DC to WAN but from WAN to DC, they are not re-advertised if unknown MAC address (and default IP address) are utilized in NVEs. In this scenario, each GW maintains a MAC-VRF (and/or IP-VRF) for each EVI. The main advantage of this approach is that NVEs do not need to maintain MAC and IP addresses from any remote data centers when default IP route and unknown MAC routes are used - i.e., they only need to maintain routes that are local to their own DC. When default IP route and unknown MAC route are used, any unknown IP and MAC packets from NVEs are forwarded to the GWs where all the VPN MAC and IP routes are maintained. This approach reduces the size of MAC-VRF and IP-VRF significantly at NVEs. Furthermore, it results in a faster convergence time upon a link or NVE failure in a multi-homed network or device redundancy scenario, because the failure related BGP routes (such as mass withdraw message) do not need to get propagated all the way to the remote NVEs in the remote DCs. This approach is described in details in section 3.4 of [DCI-EVPN-OVERLAY]. 10.2 DCI using ASBRs This approach can be considered as the opposite of the first approach and it favors simplification at DCI devices over NVEs such that larger MAC-VRF (and IP-VRF) tables are need to be maintained on NVEs; whereas, DCI devices don't need to maintain any MAC (and IP) forwarding tables. Furthermore, DCI devices do not need to terminate and processed routes related to multi-homing but rather to relay these messages for the establishment of an end-to-end LSP path. In other words, DCI devices in this approach operate similar to ASBRs for inter-AS options B. This requires locally assigned VNIs to be used just like downstream assigned MPLS VPN label where for all practical purposes the VNIs function like 24-bit VPN labels. This approach is equally applicable to data centers (or access networks) with MPLS encapsulation. In inter-AS option B, when ASBR receives an EVPN route from its DC over iBGP and re-advertises it to other ASBRs, it re-advertises the EVPN route by re-writing the BGP next-hops to itself, thus losing the identity of the PE that originated the advertisement. This re-write of BGP next-hop impacts the EVPN Mass Withdraw route (Ethernet A-D per ES) and its procedure adversely. In EVPN, the route used for aliasing (Ethernet A-D per EVI route) has the same RD as the MAC/IP routes associated with that EVI. Therefore, the receiving PE can associated the receive MAC/IP routes with its corresponding aliasing route using their RDs even if their next hop is written to the same ASBR router's address. However, in EVPN, the mass-withdraw route uses a different RD than that of its associated MAC/IP routes. Thus, the way to associate them together is via their next-hop router's address. Now, when BGP next hop address representing the originating Sajassi-Drake et al. Expires April 19, 2016 [Page 21] INTERNET DRAFT EVPN Overlay October 19, 2015 PE, gets re-written by the re-advertising ASBR, it creates ambiguity in the receiving PE that cannot be resolved. Therefore, the functionality needed at the ASBRs depends on whether the EVPN Ethernet A-D routes (per ES and/or per EVI) are originated and whether there is a need to handle route resolution ambiguity for Ethernet A-D per ES route. The following two subsections describe the functionality needed by the ASBRs depending on whether the NVEs reside in a Hypervisors or in TORs. 10.2.1 ASBR Functionality with NVEs in Hypervisors When NVEs reside in hypervisors as described in section 7.1, there is no multi-homing and thus there is no need for the originating NVE to send Ethernet A-D per ES or Ethernet A-D per EVI routes. Furthermore, the processing of these routes by the receiving NVE in the hypervisor are optional per [RFC7432] and as described in section 7. Therefore, the ambiguity issue discussed above doesn't exist for this scenario and the functionality of ASBRs are that of existing L2VPN (or L3VPN) where the ASBRs assist in setting up end-to-end LSPs among the NVEs' MAC-VRFs. As noted previously, for all practical purposes, the 24-bit locally assigned VNIs used in this scenario, function as 24-bit labels in setting up the end-to-end LSPs. 10.2.2 ASBR Functionality with NVEs in TORs When NVEs reside in TORs and operate in multi-homing redundancy mode, then as described in section 8, there is a need for the originating NVE to send Ethernet A-D per ES route(s) (used for mass withdraw) and Ethernet A-D per EVI routes (used for aliasing). As described above, the re-write of BGP next-hop by ASBRs creates ambiguities when Ethernet A-D per ES routes are received by the remote PE in a different ASBR because the receiving PE cannot associated that route with the MAC/IP routes from the same Ethernet Segment advertised by the same originating PE. This ambiguity inhibits the function of mass-withdraw per ES by the receiving PE in a different ASBR. As an example consider a scenario where CE is multi-homed to PE1 and PE2 where these PEs are connected via ASBR1 and then ASBR2 to the remote PE3. Furthermore, consider that PE1 receives M1 from CE1 but not PE2. Therefore, PE1 advertises Eth A-D per ES1, Eth A-D per EVI1, and M1; whereas, PE2 only advertises Eth A-D per ES1 and Eth A-D per EVI1. ASBR1 receives all these five advertisements and passes them to ASBR2 (with itself as the BGP next hop). ASBR2, in turn, passes them to the remote PE3 with itself as the BGP next hop. PE3 receives these five routes where all of them have the same BGP next-hop (i.e., ASBR2). Furthermore, the two Ether A-D per ES routes received by PE3 Sajassi-Drake et al. Expires April 19, 2016 [Page 22] INTERNET DRAFT EVPN Overlay October 19, 2015 have the same info - i.e., same ESI and the same BGP next hop. Although both of these routes are maintained by the BGP process in PE3, information from only one of them is used in the L2 routing table (L2 RIB). PE1 / \ CE ASBR1---ASBR2---PE3 \ / PE2 Figure 1: Inter-AS Option B Now, when the AC between the PE2 and the CE fails and PE2 sends NLRI withdrawal for Ether A-D per ES route and this withdrawal gets propagated and received by the PE3, the BGP process in PE3 removes the corresponding BGP route; however, it doesn't remove the associated info (namely ESI and BGP next hop) from the L2 routing table (L2 RIB) because it still has the other Ether A-D per ES route (originated from PE1) with the same info. That is why the mass- withdraw mechanism does not work when doing DCI with inter-AS option B. However, as described next, the Aliasing function works and so does mass-withdraw per EVI (which is associated with withdrawing the EVPN route associated with Aliasing - i.e., Ether A-D per EVI route). In the above example, the PE3 receives two Aliasing routes with the same BGP next hop (ASBR2) but different RDs. One of the Alias route has the same RD as the advertised MAC route (M1). PE3 follows the route resolution procedure specified in [RFC7432] upon receiving the two Aliasing route. PE3 should also resolve the alias path properly even though both the primary and backup paths have the same BGP next hop, they have different RDs and the alias route with the different RD than that of the MAC route is considered as the backup path. Therefore, PE3 installs both primary and backup paths (and their associated ESI/EVI MPLS labels or local VNIs) for the MAC route M1. This creates two end-to-end LSPs from PE3 to PE1 for M1 such that when PE3 wants to forward traffic destined to M1, it can load balanced between the two paths. Although route resolution for Aliasing routes with the same BGP next hop is not described in this level of details in [RFC7432], it is expected to operate as such and thus it is clarified here. When the AC between the PE2 and the CE fails and PE2 sends NLRI withdrawal for Ether A-D per EVI routes and these withdrawals get propagated and received by the PE3, the PE3 removes the Aliasing Sajassi-Drake et al. Expires April 19, 2016 [Page 23] INTERNET DRAFT EVPN Overlay October 19, 2015 route and updates all the corresponding MAC routes for that EVI to remove the backup path. This action makes the mass-withdraw functionality to perform at the per-EVI level (instead of per-ES). The mass-withdraw at per-EVI level requires more messages than that of per-ES level and thus its convergence time is not as good as per ES level. However, its convergence time is much better than individual MAC withdraw. In summary, it can be seen that aliasing and backup path functionality should work as is for inter-AS option B. Furthermore, in case of inter-AS option B, mass-withdraw functionality falls back from per-ES to per-EVI. If per-ES mass-withdraw functionality is needed along with backward compatibility, then it is recommended to use GWs (per section 10.1) instead of ASBRs for DCI. 11 Acknowledgement The authors would like to thank David Smith, John Mullooly, Thomas Nadeau for their valuable comments and feedback. The authors would also like to thank Jakob Heitz for his contribution on section 10. 12 Security Considerations This document uses IP-based tunnel technologies to support data plane transport. Consequently, the security considerations of those tunnel technologies apply. This document defines support for VXLAN and NVGRE encapsulations. The security considerations from those documents as well as [RFC4301] apply to the data plane aspects of this document. As with [RFC5512], any modification of the information that is used to form encapsulation headers, to choose a tunnel type, or to choose a particular tunnel for a particular payload type may lead to user data packets getting misrouted, misdelivered, and/or dropped. More broadly, the security considerations for the transport of IP reachability information using BGP are discussed in [RFC4271] and [RFC4272], and are equally applicable for the extensions described in this document. If the integrity of the BGP session is not itself protected, then an imposter could mount a denial-of-service attack by establishing numerous BGP sessions and forcing an IPsec SA to be created for each one. However, as such an imposter could wreak havoc on the entire routing system, this particular sort of attack is probably not of any special importance. Sajassi-Drake et al. Expires April 19, 2016 [Page 24] INTERNET DRAFT EVPN Overlay October 19, 2015 It should be noted that a BGP session may itself be transported over an IPsec tunnel. Such IPsec tunnels can provide additional security to a BGP session. The management of such IPsec tunnels is outside the scope of this document. 13 IANA Considerations IANA has allocated the following BGP Tunnel Encapsulation Attribute Tunnel Types: 8 VXLAN Encapsulation 9 NVGRE Encapsulation 10 MPLS Encapsulation 11 MPLS in GRE Encapsulation 12 VXLAN GPE Encapsulation 14 References 14.1 Normative References [KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC4271] Y. Rekhter, Ed., T. Li, Ed., S. Hares, Ed., "A Border Gateway Protocol 4 (BGP-4)", January 2006. [RFC4272] S. Murphy, "BGP Security Vulnerabilities Analysis.", January 2006. [RFC4301] S. Kent, K. Seo., "Security Architecture for the Internet Protocol.", December 2005. [RFC5512] Mohapatra, P. and E. Rosen, "The BGP Encapsulation Subsequent Address Family Identifier (SAFI) and the BGP Tunnel Encapsulation Attribute", RFC 5512, April 2009. [RFC7432] Sajassi et al., "BGP MPLS Based Ethernet VPN", RFC 7432, February 2014 14.2 Informative References [RFC7209] Sajassi et al., "Requirements for Ethernet VPN (EVPN)", RFC 7209, May 2014 [RFC7348] Mahalingam, M., et al, "VXLAN: A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks", RFC 7348, August Sajassi-Drake et al. Expires April 19, 2016 [Page 25] INTERNET DRAFT EVPN Overlay October 19, 2015 2014 [NVGRE] Garg, P., et al., "NVGRE: Network Virtualization using Generic Routing Encapsulation", draft-sridharan-virtualization-nvgre- 07.txt, November 11, 2014 [Problem-Statement] Narten et al., "Problem Statement: Overlays for Network Virtualization", draft-ietf-nvo3-overlay-problem-statement- 01, September 2012. [L3VPN-ENDSYSTEMS] Marques et al., "BGP-signaled End-system IP/VPNs", draft-ietf-l3vpn-end-system, work in progress, October 2012. [NOV3-FRWK] Lasserre et al., "Framework for DC Network Virtualization", draft-ietf-nvo3-framework-01.txt, work in progress, October 2012. Contributors S. Salam K. Patel D. Rao S. Thoria D. Cai Cisco Y. Rekhter R. Shekhar Wen Lin Nischal Sheth Juniper L. Yong Huawei Authors' Addresses Ali Sajassi Cisco Email: sajassi@cisco.com John Drake Juniper Networks Email: jdrake@juniper.net Nabil Bitar Verizon Communications Email : nabil.n.bitar@verizon.com Aldrin Isaac Juniper Email: aisaac@juniper.net Sajassi-Drake et al. Expires April 19, 2016 [Page 26] INTERNET DRAFT EVPN Overlay October 19, 2015 James Uttaro AT&T Email: uttaro@att.com Wim Henderickx Alcatel-Lucent e-mail: wim.henderickx@alcatel-lucent.com Sajassi-Drake et al. Expires April 19, 2016 [Page 27]