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Versions: 00                                                            
RIFT                                                        J. Head, Ed.
Internet-Draft                                             T. Przygienda
Intended status: Standards Track                                  W. Lin
Expires: 26 August 2021                                 Juniper Networks
                                                        22 February 2021


                             RIFT Auto-EVPN
                      draft-head-rift-auto-evpn-00

Abstract

   This document specifies procedures that allow an EVPN overlay to be
   fully and automatically provisioned when using RIFT as underlay and
   leveraging its no touch ZTP architecture.

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 https://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 26 August 2021.

Copyright Notice

   Copyright (c) 2021 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 (https://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.





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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Design Considerations . . . . . . . . . . . . . . . . . . . .   4
   3.  System ID . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Fabric ID . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Auto-EVPN Device Roles  . . . . . . . . . . . . . . . . . . .   5
     5.1.  All Participating Nodes . . . . . . . . . . . . . . . . .   5
     5.2.  ToF Nodes as Route Reflectors . . . . . . . . . . . . . .   5
     5.3.  Leaf Nodes  . . . . . . . . . . . . . . . . . . . . . . .   6
   6.  Auto-EVPN Variable Derivation . . . . . . . . . . . . . . . .   7
     6.1.  Auto-EVPN Version . . . . . . . . . . . . . . . . . . . .   8
     6.2.  MAC-VRF ID  . . . . . . . . . . . . . . . . . . . . . . .   8
     6.3.  Loopback Address  . . . . . . . . . . . . . . . . . . . .   8
       6.3.1.  Leaf Nodes as Gateways  . . . . . . . . . . . . . . .   8
       6.3.2.  ToF Nodes as Route Reflectors . . . . . . . . . . . .   9
         6.3.2.1.  Route Reflector Election Procedures . . . . . . .   9
     6.4.  Autonomous System Number  . . . . . . . . . . . . . . . .   9
     6.5.  Cluster ID  . . . . . . . . . . . . . . . . . . . . . . .  10
     6.6.  Router ID . . . . . . . . . . . . . . . . . . . . . . . .  10
     6.7.  Route Target  . . . . . . . . . . . . . . . . . . . . . .  10
     6.8.  Route Distinguisher . . . . . . . . . . . . . . . . . . .  10
     6.9.  EVPN MAC-VRF Services . . . . . . . . . . . . . . . . . .  10
       6.9.1.  Untagged Traffic in Multiple Fabrics  . . . . . . . .  11
         6.9.1.1.  VLAN  . . . . . . . . . . . . . . . . . . . . . .  11
         6.9.1.2.  VNI . . . . . . . . . . . . . . . . . . . . . . .  11
         6.9.1.3.  MAC Address . . . . . . . . . . . . . . . . . . .  11
         6.9.1.4.  IPv6 IRB Gateway Address  . . . . . . . . . . . .  11
         6.9.1.5.  IPv4 IRB Gateway Address  . . . . . . . . . . . .  11
       6.9.2.  Tagged Traffic in Multiple Fabrics  . . . . . . . . .  11
         6.9.2.1.  VLAN  . . . . . . . . . . . . . . . . . . . . . .  12
         6.9.2.2.  VNI . . . . . . . . . . . . . . . . . . . . . . .  12
         6.9.2.3.  MAC Address . . . . . . . . . . . . . . . . . . .  12
         6.9.2.4.  IPv6 IRB Gateway Address  . . . . . . . . . . . .  12
         6.9.2.5.  IPv4 IRB Gateway Address  . . . . . . . . . . . .  12
       6.9.3.  Tagged Traffic in a Single Fabric . . . . . . . . . .  12
         6.9.3.1.  VLAN  . . . . . . . . . . . . . . . . . . . . . .  12
         6.9.3.2.  VNI . . . . . . . . . . . . . . . . . . . . . . .  13
         6.9.3.3.  MAC Address . . . . . . . . . . . . . . . . . . .  13
         6.9.3.4.  IPv6 IRB Gateway Address  . . . . . . . . . . . .  13
         6.9.3.5.  IPv4 IRB Gateway Address  . . . . . . . . . . . .  13
       6.9.4.  Traffic Routed to External Destinations . . . . . . .  13
         6.9.4.1.  Route Distinguisher . . . . . . . . . . . . . . .  13
         6.9.4.2.  Route Target  . . . . . . . . . . . . . . . . . .  13
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  14
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  14
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  14



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     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  14
   Appendix A.  Appendix . . . . . . . . . . . . . . . . . . . . . .  14
     A.1.  RIFT LIE Schema . . . . . . . . . . . . . . . . . . . . .  14
       A.1.1.  Auto-EVPN Version . . . . . . . . . . . . . . . . . .  14
       A.1.2.  Fabric ID . . . . . . . . . . . . . . . . . . . . . .  14
     A.2.  RIFT Node-TIE Schema  . . . . . . . . . . . . . . . . . .  15
       A.2.1.  Auto-EVPN Version . . . . . . . . . . . . . . . . . .  15
       A.2.2.  Fabric ID . . . . . . . . . . . . . . . . . . . . . .  15
     A.3.  Variable Derivation . . . . . . . . . . . . . . . . . . .  15
       A.3.1.  Random Seed Values  . . . . . . . . . . . . . . . . .  15
       A.3.2.  Fabric ID . . . . . . . . . . . . . . . . . . . . . .  15
       A.3.3.  Loopback Address  . . . . . . . . . . . . . . . . . .  15
       A.3.4.  Autonomous System Number  . . . . . . . . . . . . . .  15
       A.3.5.  Cluster ID  . . . . . . . . . . . . . . . . . . . . .  15
       A.3.6.  Router ID . . . . . . . . . . . . . . . . . . . . . .  15
       A.3.7.  Route Target  . . . . . . . . . . . . . . . . . . . .  15
       A.3.8.  Route Distinguisher . . . . . . . . . . . . . . . . .  16
       A.3.9.  VLAN  . . . . . . . . . . . . . . . . . . . . . . . .  16
       A.3.10. VNI . . . . . . . . . . . . . . . . . . . . . . . . .  16
       A.3.11. Gateway (MAC) . . . . . . . . . . . . . . . . . . . .  16
       A.3.12. Gateway (IPv6)  . . . . . . . . . . . . . . . . . . .  16
       A.3.13. Gateway (IPv4)  . . . . . . . . . . . . . . . . . . .  16
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  16

1.  Introduction

   RIFT is a protocol that focuses heavily on operational simplicity.
   [RIFT] natively supports Zero Touch Provisioning (ZTP) functionality
   that allows each node in an underlay network to automatically derive
   its place in the topology and configure itself accordingly when
   properly cabled.  RIFT can also disseminate Key-Value information
   contained in Key-Value Topology Information Elements (KV-TIEs).
   These KV-TIEs can contain any information and therefore be used for
   any purpose.  Leveraging RIFT to provision EVPN overlays without any
   need for configuration and leveraging KV capabilities to easily
   validate correct operation of such overlay without a single point of
   failure would provide significant benefit to operators in terms of
   simplicity and robustness of such a solution.

1.1.  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 RFC 2119 [RFC2119].







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2.  Design Considerations

   EVPN supports various service models, this document defines a method
   for the VLAN-Aware service model defined in [RFC7432].  Other service
   models may be considered in future revisions of this document.

   Each model has its own set of requirements for deployment.  For
   example, a functional BGP overlay is necessary to exchange EVPN NLRI
   regardless of the service model.  Furthermore, the requirements are
   made up of individual variables, such as each node's loopback address
   and AS number for the BGP session.  Some of these variables may be
   coordinated across each node in a network, but are ultimately locally
   significant (e.g. route distinguishers).  Similarly, calculation of
   some variables will be local only to each device.  RIFT contains
   currently enough topology information in each node to calculate all
   those necessary variables automatically.

   Once the EVPN overlay is configured and becomes operational KV TIEs
   can be used to distribute state information to allow for validation
   of basic operational correctness without need for further tooling.

3.  System ID

   The 64-bit RIFT System ID that uniquely identifies a node as defined
   in [RIFT].

4.  Fabric ID

   RIFT operates on variants of Clos substrate which are commonly called
   an IP Fabric.  Since EVPN VLANs can be either contained within one
   fabric or span them, Auto-EVPN introduces the concept of a Fabric ID
   into RIFT.

   This section describes an optional extension to LIE packet schema in
   the form of a 16-bit Fabric ID that identifies a nodes membership
   within a particular fabric.  Auto-EVPN capable nodes MUST support
   this extension but MAY not advertise it when not participating in
   Auto-EVPN.  A non-present Fabric ID and value of 0 is reserved as
   ANY_FABRIC and MUST NOT be used for any other purpose.

   Fabric ID MUST be considered in existing adjacency FSM rules so nodes
   that support Auto-EVPN can interoperate with nodes that do not.  The
   LIE validation is extended with following clause and if it is not
   met, miscabling should be declared:







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           (if fabric_id is not advertised by either node OR
           if fabric_id is identical on both nodes)
           AND
           (if auto_evpn_version is not advertised by either node OR
           if auto_evpn_version is identical on both nodes)

   The appendix details LIE (Appendix A.1.2) and Node-TIE
   (Appendix A.2.2) schema changes.

5.  Auto-EVPN Device Roles

   Auto-EVPN requires that each node understand its given role within
   the scope of the EVPN implementation so each node derives the
   necessary variables and provides the necessary overlay configuration.
   For example, a leaf node performing VXLAN gateway functions does not
   need to derive its own Cluster ID or learn one from the route
   reflector that it peers with.

5.1.  All Participating Nodes

   Not all nodes have to participate in Auto-EVPN but when they do they
   do assume EVPN roles and MUST derive according variables:

      *IPv6 Loopback Address*
         Unique IPv6 loopback address used in BGP sessions.

      *Router ID*
         The BGP Router ID.

      *Autonomous System Number*
         The ASN for IBGP sessions.

      *Cluster ID*
         The Cluster ID for Top-of-Fabric IBGP route reflection.

5.2.  ToF Nodes as Route Reflectors

   This section defines an Auto-EVPN role whereby some Top-of-Fabric
   nodes act as EVPN route reflectors.  It is expected that route
   reflectors would establish IBGP sessions with leaf nodes in the same
   fabric.  The typical route reflector requirements do not change,
   however determining which specific values to use requires further
   consideration.  ToF nodes performing route reflector functionality
   MUST derive the following variables:

      *IPv6 RR Loopback Address*
         The source address for IBGP sessions with leaf nodes in case
         ToF won election for one of the route reflectors in the fabric.



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      *IPv6 RR Acceptable Prefix Range*
         Range of addresses acceptable by the route reflector to form a
         IBGP session.  This range covers ALL possible IPv6 Loopback
         Addresses derived by other Auto EVPN nodes in the current
         fabric and other Auto-EVPN RRs addresses.

5.3.  Leaf Nodes

   Leaf nodes derive their role from realizing they are at the bottom of
   the fabric, i.e. not having any southbound adjacencies.  Alternately,
   a node can assume a leaf node if it has only southbound adjacencies
   to nodes with explicit LEAF_LEVEL to allow for scenarios where RIFT
   leaves do NOT participate in Auto-EVPN.

   Leaf nodes MUST derive the following variables:

      *IPv6 RR Loopback Adresses*
         Addresses of the RRs present in the fabric.  Those addresses
         are used to build BGP sessions to the RR.

      *EVIs*
         Leaf node derives all the necessary variables to instantiate
         EVIs with layer-2 and optionally layer-3 functionality.

   If a leaf node is required to perform layer-2 VXLAN gateway
   functions, it MUST be capable of deriving the following types of
   variables:

      *Route Distinguisher*
         The route distinguisher corresponding to a MAC-VRF that
         uniquely identifies each node.

      *Route Target*
         The route target that corresponds to a MAC-VRF.

      *MAC VRF name*
         This is an optional variable to provide a common MAC VRF name
         across all leaves.

      *Set of VLANs*
         Those are VLANs provisioned either within the fabric or
         allowing to stretch across fabrics.

   For each VLAN derived in an EVI the following variables MUST be
   derived:

      *VLAN*
         The VLAN ID.



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      *name*
         This is an optional variable to provide a common VLAN name
         across all leaves.

      *VNI*
         The VNI that corresponds to the VLAN ID.  This will contribute
         to the EVPN Type-2 route.

      *IRB*
         Optional variables of the IRB for the VLAN if the leaf performs
         layer-3 gateway function.

   If a leaf node is required to perform layer-3 VXLAN gateway
   functions, it MUST additionally be capable of deriving the following
   types of variables:

      *IP Gateway MAC Address*
         The MAC address associated with IP gateway.

      *IP Gateway Subnetted Address*
         The IPv4 and/or IPv6 gateway address including its subnet
         length.

   Type-5 EVPN IP Prefix with ToFs performing gateway functionality can
   also be derived and will be described in a future version of this
   document.

6.  Auto-EVPN Variable Derivation

   As previously mentioned, not all nodes are required to derive all
   variables in a given network (e.g. a transit spine node may not need
   to derive any or participate in Auto-EVPN).  Additionally, all
   derived variables are derived from RIFT's FSM or ZTP mechanism so no
   additional flooding beside RIFT flooding is necessary for the
   functionality.

   It is also important to mention that all variable derivation is in
   some way based on combinations of System ID, MAC-VRF ID, Fabric ID,
   EVI and VLAN and MUST comply precisely with calculation methods
   specified in the Appendix section to allow interoperability between
   different implementations.










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6.1.  Auto-EVPN Version

   This section describes extensions to both the RIFT LIE packet and
   Node-TIE schemas in the form of a 16-bit value that identifies the
   Auto-EVPN Version.  Auto-EVPN capable nodes MUST support this
   extension, but MAY choose not to advertise it in LIEs and Node-TIEs
   when Auto-EVPN is not being utilized.  The appendix describes LIE
   (Appendix A.1.1) and Node-TIE (Appendix A.2.1) schema changes in
   detail.

6.2.  MAC-VRF ID

   This section describes a variable MAC-VRF ID that uniquely identifies
   an instance of EVPN instance (EVI) and is used in variable derivation
   procedures.  Each EVPN EVI MUST be associated with a unique MAC-VRF
   ID, this document does not specify a method for making that
   association or ensuring that they are coordinated properly across
   fabric(s).

6.3.  Loopback Address

   First and foremost, RIFT does not advertise anything more specific
   than the fabric default route in the southbound direction by default.
   However, Auto-EVPN nodes MUST advertise specific loopback addresses
   southbound to all other Auto-EVPN nodes so to establish MP-BGP
   reachability correctly in all scenarios.

   Auto-EVPN nodes MUST derive a ULA-scoped IPv6 loopback address to be
   used as both the IBGP source address, as well as the VTEP source when
   VXLAN gateways are required.  Calculation is done using the 6-bytes
   of reserved ULA space, the 2-byte Fabric ID, and the node's 8-byte
   System ID.  Derivation of the System ID varies slightly depending
   upon the node's location/role in the fabric and will be described in
   subsequent sections.

   IPv4 addresses MAY be supported, but it should be noted that they
   have a higher likelihood of collision.

   The required algorithm can be found in the appendix (Appendix A.3.3).

6.3.1.  Leaf Nodes as Gateways

   Calculation is done using the 6-bytes of reserved ULA space, the
   2-byte Fabric ID, and the node's 8-byte System ID.







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6.3.2.  ToF Nodes as Route Reflectors

   ToF nodes acting as route reflectors MUST derive their loopback
   address according to the specific section describing the algorithm.
   Calculation is done using the 6-bytes of reserved ULA space, the
   2-byte Fabric ID, and the 8-byte System ID of each elected route
   reflector.

6.3.2.1.  Route Reflector Election Procedures

   Four Top-of-Fabric nodes MUST be elected as an IBGP route reflector.
   Each ToF performs the election independently based on system IDs of
   other ToFs in the fabric obtained via southbound reflection.  The
   route reflector election procedures are defined as follows:

   1.  ToF node with the highest System ID.

   2.  ToF node with the lowest System ID.

   3.  ToF node with the 2nd highest System ID.

   4.  ToF node with the 2nd lowest System ID.

   This ordering is necessary to prevent a single node with either the
   highest or lowest System ID from triggering changes to route
   reflector loopback addresses as it would result in all BGP sessions
   dropping.

   For example, if two nodes, ToF01 and ToF02 with System IDs
   002c6af5a281c000 and 002c6bf5788fc000 respectively, ToF02 would be
   elected due to it having the highest System ID of the ToFs
   (002c6bf5788fc000).  If a ToF determines that it is elected as route
   reflector, it uses the knowledge of its position in the list to
   derive route reflector v6 loopback address.

   Considerations for multiplane route reflector elections will be
   included in future revisions.

6.4.  Autonomous System Number

   Nodes in each fabric MUST derive a private autonomous system number
   based on its Fabric ID so that it is unique across the fabric.

   The required algorithm for 2-byte ASNs can be found in the appendix
   (Appendix A.3.4).






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6.5.  Cluster ID

   Route reflector nodes in each fabric MUST derive a cluster ID that is
   based on its Fabric ID so that it is unique across the fabric.
   Implementations MAY choose to simply use the AS number as the cluster
   ID.

   The required algorithm can be found in the appendix (Appendix A.3.5).

6.6.  Router ID

   Nodes MUST drive a Router ID that is based on both its System ID and
   Fabric ID so that it is unique to both.

   The required algorithm can be found in the appendix (Appendix A.3.6).

6.7.  Route Target

   Nodes hosting EVPN EVIs MUST derive a route target extended community
   based on the MAC-VRF ID for each EVI so that it is unique across the
   network.  Route targets MUST be of type 0 as per RFC4360.

   For example, if given a MAC-VRF ID of 1, the derived route target
   would be "target:1"

   The required algorithm can be found in the appendix (Appendix A.3.7).

6.8.  Route Distinguisher

   Nodes hosting EVPN EVIs MUST derive a type-0 route distinguisher
   based on its System ID and Fabric ID so that it is unique per MAC-VRF
   and per node.

   The required algorithm can be found in the appendix (Appendix A.3.8).

6.9.  EVPN MAC-VRF Services

   It's obvious that applications utilizing Auto-EVPN overlay services
   may require a variety of layer-2 and/or layer-3 traffic
   considerations.  Variables supporting these services are also derived
   based on some combination of MAC-VRF ID, Fabric ID, and other
   constant values.  Integrated Routing and Bridging (IRB) gateway
   address derivation also leverages a set of constant "random seed"
   values to provide additional entropy.

   The required derivation procedures can be found in the appendix
   (Appendix A.3).




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6.9.1.  Untagged Traffic in Multiple Fabrics

   This section defines a methods to derive unique VLAN, VNI, MAC, and
   gateway address values for deployments where untagged traffic is
   stretched across multiple fabrics.

6.9.1.1.  VLAN

   Untagged traffic stretched across multiple fabrics MUST derive VLAN
   tags based on MAC-VRF ID in conjunction with a constant value of 1
   (i.e.  MAC-VRF ID + 1).

6.9.1.2.  VNI

   Untagged traffic stretched across multiple fabrics MUST derive VNIs
   based on MAC-VRF ID and Fabric ID in conjunction with a constant
   value.  These VNIs MUST correspond to EVPN Type-2 routes.

6.9.1.3.  MAC Address

   The MAC address MUST be a unicast address and also MUST be identical
   for any IRB gateways that belong to an individual bridge-domain
   across fabrics.  The last 5-bytes MUST be a hash of the MAC-VRF ID
   and a constant value of 1 that is calculated using the previously
   mentioned random seed values.

6.9.1.4.  IPv6 IRB Gateway Address

   The derived IPv6 gateway address MUST be from a ULA-scoped range that
   will account for the first 6-bytes.  The next 5-bytes MUST be the
   last bytes of the derived MAC address.  Finally, the remaining
   7-bytes MUST be ::0001.

6.9.1.5.  IPv4 IRB Gateway Address

   The derived IPv4 gateway address MUST be from a RFC1918 range, which
   accounts for the first octet.  The next octet MUST a hash of the MAC-
   VRF ID and a constant value of 1 that is calculated using the
   previously mentioned random seed values.  Finally, the remaining 2
   octets MUST be 0 and 1 respectively.

6.9.2.  Tagged Traffic in Multiple Fabrics

   This section defines a methods to derive unique VLAN, VNI, MAC, and
   gateway address values for deployments where tagged traffic is
   stretched across multiple fabrics.





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6.9.2.1.  VLAN

   Tagged traffic stretched across multiple fabrics MUST derive VLAN
   tags based on MAC-VRF ID in conjunction with a constant value of 16
   (i.e.  MAC-VRF ID + 16).

6.9.2.2.  VNI

   Tagged traffic stretched across multiple fabrics MUST derive VNIs
   based on MAC-VRF ID and Fabric ID in conjunction with a constant
   value.  These VNIs MUST correspond to EVPN Type-2 routes.

6.9.2.3.  MAC Address

   The MAC address MUST be a unicast address and also MUST be identical
   for any IRB gateways that belong to an individual bridge-domain
   across fabrics.  The last 5-bytes MUST be a hash of the MAC-VRF ID
   and a constant value of 1 that is calculated using the previously
   mentioned random seed values.

6.9.2.4.  IPv6 IRB Gateway Address

   The derived IPv6 gateway address MUST be from a ULA-scoped range that
   will account for the first 6-bytes.  The next 5-bytes MUST be the
   last bytes of the derived MAC address.  Finally, the remaining
   7-bytes MUST be ::0001.

6.9.2.5.  IPv4 IRB Gateway Address

   The derived IPv4 gateway address MUST be from a RFC1918 range, which
   accounts for the first octet.  The next octet MUST a hash of the MAC-
   VRF ID and a constant value of 16 that is calculated using the
   previously mentioned random seed values.  Finally, the remaining 2
   octets MUST be 0 and 1 respectively.

6.9.3.  Tagged Traffic in a Single Fabric

   This section defines a methods to derive unique VLAN, VNI, MAC, and
   gateway address values for deployments where untagged traffic is
   contained within a single fabric.

6.9.3.1.  VLAN

   Tagged traffic contained to a single fabric MUST derive VLAN tags
   based on MAC-VRF ID and Fabric ID in conjunction with a constant
   value of 17 (i.e.  MAC-VRF ID + Fabric ID + 17).





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6.9.3.2.  VNI

   Tagged traffic contained to a single fabric MUST derive VNIs based on
   MAC-VRF ID and Fabric ID in conjunction with a constant value.  These
   VNIs MUST correspond to EVPN Type-2 routes.

6.9.3.3.  MAC Address

   The MAC address MUST be a unicast address and also MUST be identical
   for any IRB gateways that belong to an individual bridge-domain
   across fabrics.  The last 5-bytes MUST be a hash of the MAC-VRF ID
   and a constant value of 1 that is calculated using the previously
   mentioned random seed values.

6.9.3.4.  IPv6 IRB Gateway Address

   The derived IPv6 gateway address MUST be from a ULA-scoped range,
   which accounts for the first 6-bytes.  The next 5-bytes MUST be the
   last bytes of the derived MAC address.  Finally, the remaining
   7-bytes MUST be ::0001.

6.9.3.5.  IPv4 IRB Gateway Address

   The derived IPv4 gateway address MUST be from a RFC1918 range, which
   accounts for the first octet.  The next octet MUST a hash of the MAC-
   VRF ID and a constant value of 17 that is calculated using the
   previously mentioned random seed values.  Finally, the remaining 2
   octets MUST be 0 and 1 respectively.

6.9.4.  Traffic Routed to External Destinations

6.9.4.1.  Route Distinguisher

   Nodes hosting IP Prefix routes MUST derive a type-0 route
   distinguisher based on its System ID and Fabric ID so that it is
   unique per IP-VRF and per node.

   The required algorithm can be found in the appendix (Appendix A.3.8).

6.9.4.2.  Route Target

   Nodes hosting IP prefix routes MUST derive a route target extended
   community based on the MAC-VRF ID for each IP-VRF so that it is
   unique across the network.  Route targets MUST be of type 0.

   The required algorithm can be found in the appendix (Appendix A.3.7).





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7.  Acknowledgements

   TBD

8.  Security Considerations

   This document introduces no new security concerns to RIFT or other
   specifications referenced in this document.

9.  References

9.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC7432]  Sajassi, A., Aggarwal, R., Bitar, N., Isaac, A., Uttaro,
              J., Drake, J., and W. Henderickx, "BGP MPLS-Based Ethernet
              VPN", February 2015,
              <https://www.rfc-editor.org/info/rfc7432>.

   [RIFT]     Przygienda, T., Sharma, A., Thubert, P., Rijsman, B., and
              D. Afanasiev, "RIFT: Routing in Fat Trees", Work in
              Progress, draft-ietf-rift-rift-12, May 2020.

Appendix A.  Appendix

A.1.  RIFT LIE Schema

A.1.1.  Auto-EVPN Version

   struct LIEPacket {
    ...
      /** It provides the optional ID of the configured fabric  */
      25: optional common.FabricIDType       fabric_id;
   ...

A.1.2.  Fabric ID

   ...
   struct LIEPacket {
    ...
      /** It provides optional version of EVPN ZTP as 256 * MAJOR + MINOR */
      26: optional i16                       auto_evpn_version;
   ...




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A.2.  RIFT Node-TIE Schema

A.2.1.  Auto-EVPN Version

   struct NodeTIEElement {
   ...
      /** It provides optional version of EVPN ZTP as 256 * MAJOR + MINOR */
      13: optional i16                         auto_evpn_version;

A.2.2.  Fabric ID

     struct NodeTIEElement {
     ...
       /** It provides the optional ID of the Fabric configured */
      12: optional common.FabricIDType         fabric_id;

A.3.  Variable Derivation

A.3.1.  Random Seed Values

   To be provided in future version of this document.

A.3.2.  Fabric ID

   To be provided in future version of this document.

A.3.3.  Loopback Address

   To be provided in future version of this document.

A.3.4.  Autonomous System Number

   To be provided in future version of this document.

A.3.5.  Cluster ID

   To be provided in future version of this document.

A.3.6.  Router ID

   To be provided in future version of this document.

A.3.7.  Route Target

   To be provided in future version of this document.






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A.3.8.  Route Distinguisher

   To be provided in future version of this document.

A.3.9.  VLAN

   To be provided in future version of this document.

A.3.10.  VNI

   To be provided in future version of this document.

A.3.11.  Gateway (MAC)

   To be provided in future version of this document.

A.3.12.  Gateway (IPv6)

   To be provided in future version of this document.

A.3.13.  Gateway (IPv4)

   To be provided in future version of this document.

Authors' Addresses

   Jordan Head (editor)
   Juniper Networks
   1137 Innovation Way
   Sunnyvale, CA
   United States of America

   Email: jhead@juniper.net


   Tony Przygienda
   Juniper Networks
   1137 Innovation Way
   Sunnyvale, CA
   United States of America

   Email: prz@juniper.net









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   Wen Lin
   Juniper Networks
   10 Technology Park Drive
   Westford, MA
   United States of America

   Email: wlin@juniper.net












































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