Internet DRAFT - draft-head-rift-auto-evpn
draft-head-rift-auto-evpn
RIFT J. Head, Ed.
Internet-Draft T. Przygienda
Intended status: Standards Track W. Lin
Expires: 10 January 2022 Juniper Networks
9 July 2021
RIFT Auto-EVPN
draft-head-rift-auto-evpn-01
Abstract
This document specifies procedures that allow an EVPN overlay to be
fully and automatically provisioned when using RIFT as underlay by
leveraging RIFT's no-touch ZTP architecture.
Status of This Memo
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Copyright (c) 2021 IETF Trust and the persons identified as the
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Design Considerations . . . . . . . . . . . . . . . . . . . . 3
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 . . . . . . . . . . . . . . . . 10
6.5. Router ID . . . . . . . . . . . . . . . . . . . . . . . . 10
6.6. Cluster ID . . . . . . . . . . . . . . . . . . . . . . . 10
6.7. Route Target . . . . . . . . . . . . . . . . . . . . . . 10
6.8. Route Distinguisher . . . . . . . . . . . . . . . . . . . 10
6.9. EVPN MAC-VRF Services . . . . . . . . . . . . . . . . . . 11
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 . . . . . . . . . . . . 12
6.9.1.5. IPv4 IRB Gateway Address . . . . . . . . . . . . 12
6.9.2. Tagged Traffic in Multiple Fabrics . . . . . . . . . 12
6.9.2.1. VLAN . . . . . . . . . . . . . . . . . . . . . . 12
6.9.2.2. VNI . . . . . . . . . . . . . . . . . . . . . . . 12
6.9.2.3. MAC Address . . . . . . . . . . . . . . . . . . . 13
6.9.2.4. IPv6 IRB Gateway Address . . . . . . . . . . . . 13
6.9.2.5. IPv4 IRB Gateway Address . . . . . . . . . . . . 13
6.9.3. Tagged Traffic in a Single Fabric . . . . . . . . . . 13
6.9.3.1. VLAN . . . . . . . . . . . . . . . . . . . . . . 13
6.9.3.2. VNI . . . . . . . . . . . . . . . . . . . . . . . 14
6.9.3.3. MAC Address . . . . . . . . . . . . . . . . . . . 14
6.9.3.4. IPv6 IRB Gateway Address . . . . . . . . . . . . 14
6.9.3.5. IPv4 IRB Gateway Address . . . . . . . . . . . . 14
6.9.4. Traffic Routed to External Destinations . . . . . . . 14
6.9.4.1. Route Distinguisher . . . . . . . . . . . . . . . 15
6.9.4.2. Route Target . . . . . . . . . . . . . . . . . . 15
6.10. Auto-EVPN Analytics . . . . . . . . . . . . . . . . . . . 15
6.10.1. Auto-EVPN Global Analytics Key Type . . . . . . . . 16
6.10.2. Auto-EVPN MAC-VRF Key Type . . . . . . . . . . . . . 16
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7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 18
8. Security Considerations . . . . . . . . . . . . . . . . . . . 18
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 18
9.1. Normative References . . . . . . . . . . . . . . . . . . 18
Appendix A. Thrift Models . . . . . . . . . . . . . . . . . . . 19
A.1. RIFT LIE Schema . . . . . . . . . . . . . . . . . . . . . 19
A.1.1. Auto-EVPN Version . . . . . . . . . . . . . . . . . . 19
A.1.2. Fabric ID . . . . . . . . . . . . . . . . . . . . . . 19
A.2. RIFT Node-TIE Schema . . . . . . . . . . . . . . . . . . 19
A.2.1. Auto-EVPN Version . . . . . . . . . . . . . . . . . . 19
A.2.2. Fabric ID . . . . . . . . . . . . . . . . . . . . . . 19
A.3. common_evpn.thrift . . . . . . . . . . . . . . . . . . . 19
A.4. auto_evpn_kv.thrift . . . . . . . . . . . . . . . . . . . 22
Appendix B. Auto-EVPN Variable Derivation . . . . . . . . . . . 24
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 36
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)
[RIFT-KV]. 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].
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
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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, RIFT
Key-Value TIEs can be used to distribute state information to allow
for validation of basic operational correctness without the need for
further tooling.
3. System ID
The 64-bit RIFT System ID that uniquely identifies a node as defined
in RIFT [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:
(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.
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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, however if a node
does assume an Auto-EVPN role, it MUST derive the following
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.
*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.
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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 Addresses*
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.
*Name*
This is an optional variable to provide a common VLAN name
across all leaves.
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*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 Auto-EVPN Variable Derivation section to allow
interoperability between different implementations. All foundational
code elements such as imports, constants, etc. are also mentioned
there.
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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.
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.
In order for leaf nodes to derive IPv6 loopback addresses, algorithms
shown in both auto_evpn_fidsidv6loopback (Figure 24) and
auto_evpn_v6prefixfidsid2loopback (Figure 9) are required.
IPv4 addresses MAY be supported, but it should be noted that they
have a higher likelihood of collision. The appendix contains the
required auto_evpn_fidsid2v4loopback (Figure 23) algorithm to support
IPv4 loopback derivation.
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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.
In order for the ToF nodes to derive IPv6 loopbacks, the algorithms
shown in both auto_evpn_fidsidv6loopback (Figure 24) and
auto_evpn_fidrrpref2rrloopback (Figure 10) are required.
In order for the ToF derive the necessary prefix range to facilitate
peering requests from any leaf, the algorithm shown in
"auto_evpn_fid2fabric_prefixes" (Figure 8) is required.
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.
The algorithm shown in "auto_evpn_sids2rrs" (Figure 6) is required to
accomplish this.
Considerations for multiplane route reflector elections will be
included in future revisions.
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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 algorithm shown in auto_evpn_fid2private_AS (Figure 25) is
required to derive the private ASN.
6.5. 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 algorithm shown in auto_evpn_sidfid2bgpid (Figure 11) is required
to derive the BGP Router ID.
6.6. 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.
The algorithm shown in auto_evpn_fid2clusterid (Figure 26) is
required to derive the BGP Cluster ID.
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 algorithm shown in auto_evpn_evi2rt (Figure 12) is required to
derive the Route Target community.
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 algorithm shown in auto_evpn_sidfid2rd (Figure 18) is required to
derive the Route Distinguisher.
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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 RANDOMSEEDS
(Figure 5) values that MUST be used to provide additional entropy.
In order to ensure that VLAN ID's don't collide, a single deployment
SHOULD NOT exceed 3 fabrics with 3 EVIs where each EVI terminate 15
VLANs. The algorithms shown in auto_evpn_fidevivlansvlans2desc
(Figure 16) and auto_evpn_vlan_description_table (Figure 15) are
required to derive VLANs accordingly. An implementation MAY exceed
this, but MUST indicate methods to ensure collision-free derivation
and describe which VLANs are stretched across fabrics.
6.9.1. Untagged Traffic in Multiple Fabrics
This section defines 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.
The algorithm shown in auto_evpn_fidevivid2vni (Figure 14) is
required to derive VNIs for Type-2 EVPN 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.
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The algorithm shown in auto_evpn_fidevividsid2mac (Figure 22) is
required to derive MAC addresses.
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.
The algorithm shown in auto_evpn_fidevividsid2v6subnet (Figure 21) is
required to derive the IPv6 gateway address.
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.
The algorithm shown in auto_evpn_v4prefixfidevividsid2v4subnet
(Figure 19) is required to derive the IPv4 gateway address. It
should be noted that there is a higher likelihood of address
collisions when deriving IPv4 addresses.
6.9.2. Tagged Traffic in Multiple Fabrics
This section defines methods to derive unique VLAN, VNI, MAC, and
gateway address values for deployments where tagged traffic is
stretched across multiple fabrics.
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.
The algorithm shown in auto_evpn_fidevivid2vni (Figure 14) is
required to derive VNIs for Type-2 EVPN routes.
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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.
The algorithm shown in auto_evpn_fidevividsid2mac (Figure 22) is
required to derive MAC addresses.
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.
The algorithm shown in auto_evpn_fidevividsid2v6subnet (Figure 21) is
required to derive the IPv6 gateway address.
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.
The algorithm shown in auto_evpn_v4prefixfidevividsid2v4subnet
(Figure 19) is required to derive the IPv4 gateway address. It
should be noted that there is a higher likelihood of address
collisions when deriving IPv4 addresses.
6.9.3. Tagged Traffic in a Single Fabric
This section defines a method 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.
The algorithm shown in auto_evpn_fidevivid2vni (Figure 14) is
required to derive VNIs for Type-2 EVPN 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.
The algorithm shown in auto_evpn_fidevividsid2mac (Figure 22) is
required to derive MAC addresses.
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.
The algorithm shown in auto_evpn_fidevividsid2v6subnet (Figure 21) is
required to derive the IPv6 gateway address.
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.
The algorithm shown in auto_evpn_v4prefixfidevividsid2v4subnet
(Figure 19) is required to derive the IPv4 gateway address. It
should be noted that there is a higher likelihood of address
collisions when deriving IPv4 addresses.
6.9.4. Traffic Routed to External Destinations
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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 algorithm shown in auto_evpn_sidfid2rd (Figure 18) is required to
derive the Route Target.
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 algorithm shown in auto_evpn_evi2rt (Figure 12) is required to
derive the Route Target community.
6.10. Auto-EVPN Analytics
Leaf nodes MAY optionally advertise analytics information about the
Auto-EVPN fabric to ToF nodes using RIFT Key-Value TIEs. This may be
advantageous in that overlay validation and troubleshooting
activities can be performed on the ToF nodes.
This section requests suggested values from the RIFT Well-Known Key-
Type Registry and describes their use for Auto-EVPN.
+===================+=======+====================================+
| Name | Value | Description |
+===================+=======+====================================+
| Auto-EVPN | 3 | Analytics describing a MAC-VRF on |
| Analytics MAC-VRF | | a particular node within a fabric. |
+-------------------+-------+------------------------------------+
| Auto-EVPN | 4 | Analytics describing an Auto-EVPN |
| Analytics Global | | node within a fabric. |
+-------------------+-------+------------------------------------+
Table 1: Requested RIFT Key Registry Values
The normative Thrift schema can be found in the appendix
(Appendix A.4).
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6.10.1. Auto-EVPN Global Analytics Key Type
This Key Type describes node level information within the context of
the Auto-EVPN fabric. The System ID of the advertising leaf node
MUST be used to differentiate the node among other nodes in the
fabric.
The Auto-EVPN Global Key Type MUST be advertised with the RIFT Fabric
ID encoded into the 3rd and 4th bytes of the Key Identifier.
0 1 2 3
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Well-Known | Auto-EVPN (Global) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| (Auto-EVPN Role, |
| Established BGP Peer Count, |
| Total BGP Peer Count,) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Auto-EVPN Global Key-Value TIE
where:
Auto-EVPN Role:
The value indicating the node's Auto-EVPN role within the
fabric.
0: Illegal value, MUST NOT be used.
1: Auto-EVPN Leaf Gateway
2: Auto-EVPN Top-of-Fabric Gateway
Established BGP Session Count:
A 16-bit integer indicating the number of BGP sessions in the
Established state.
Total BGP Peer Count:
A 16-bit integer indicating the total number of possible BGP
sessions on the local node, regardless of state.
6.10.2. Auto-EVPN MAC-VRF Key Type
This Key-Value structure contains information about a specific MAC-
VRF within the Auto-EVPN fabric.
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The Auto-EVPN MAC-VRF Key Type MUST be advertised with the Auto-EVPN
MAC-VRF ID encoded into the 3rd and 4th bytes of the Key Identifier.
All values advertised in a MAC-VRF Key-Value TIE MUST represent only
state of the local node.
0 1 2 3
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Well-Known | Auto-EVPN (MAC-VRF) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| (Operational CE Interface Count, |
| Total CE Interface Count, |
| Operational IRB Interface Count, |
| Total IRB Interface Count, |
| EVPN Type-2 MAC Route Count, |
| EVPN Type-2 MAC/IP Route Count, |
| Configured VLAN Count, |
| MAC-VRF Name, |
| MAC-VRF Description,) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Auto-EVPN MAC-VRF Key-Value TIE
where:
Operational Customer Edge Interface Count:
A 16-bit integer indicating the number of CE interfaces
associated with the MAC-VRF where both administrative and
operational status are "up".
Total Customer Edge Interface Count:
A 16-bit integer indicating the total number of CE interfaces
associated with the MAC-VRF regardless of interface status.
Operational IRB Interface Count:
A 16-bit integer indicating the number of IRB interfaces
associated with the MAC-VRF where both administrative and
operational status are "up".
Total IRB Interface Count:
A 16-bit integer indicating the total number of IRB interfaces
associated with the MAC-VRF regardless of interface status.
EVPN Type-2 MAC Route Count:
A 32-bit integer indicating the total number of EVPN Type-2 MAC
routes.
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EVPN Type-2 MAC/IP Route Count:
A 32-bit integer indicating the total number of EVPN Type-2
MAC/IP routes.
VLAN Count:
A 16-bit integer indicating the total number configured VLANs.
MAC-VRF Name:
A string used to indicate the name of the MAC-VRF on the node.
MAC-VRF Description:
A string used to describe the MAC-VRF on the node, similar to
that of an interface description.
7. Acknowledgements
The authors would like to thank Olivier Vandezande, Matthew Jones,
and Michal Styszynski for their contributions.
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-13, July 2021.
[RIFT-KV] Head, J. and T. Przygienda, "RIFT Keys Structure and Well-
Known Registry in Key Value TIE", Work in Progress, draft-
head-rift-kv-registry-01, July 2021.
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Appendix A. Thrift Models
This section contains the normative Thrift models required to support
Auto-EVPN. Per the main RIFT [RIFT] specification, all signed values
MUST be interpreted as unsigned values.
A.1. RIFT LIE Schema
A.1.1. Auto-EVPN Version
struct LIEPacket {
...
/** It provides optional version of EVPN ZTP as 256 * MAJOR + MINOR */
26: optional i16 auto_evpn_version;
...
A.1.2. Fabric ID
struct LIEPacket {
...
/** It provides the optional ID of the configured fabric */
25: optional common.FabricIDType fabric_id;
...
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. common_evpn.thrift
This section contains the normative Auto-EVPN Thrift schema.
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/**
Thrift file for common AUTO EVPN definitions for RIFT
Copyright (c) Juniper Networks, Inc., 2016-
All rights reserved.
*/
namespace py common_evpn
namespace rs models
include "common.thrift"
include "encoding.thrift"
include "statistics.thrift"
const common.FabricIDType default_fabric_id = 1
const i8 default_evis = 3
const i8 default_vlans_per_evi = 7
typedef i32 RouterIDType
typedef i32 ASType
typedef i32 ClusterIDType
struct EVPNAnyRole {
1: required common.IPv6Address v6_loopback,
2: required common.IPv6Address type5_v6_loopback,
3: required common.IPv4Address type5_v4_loopback,
4: required RouterIDType bgp_router_id,
5: required ASType autonomous_system,
6: required ClusterIDType cluster_id,
/** prefixes to be redistributed north */
7: required set<common.IPPrefixType> redistribute_north,
/** prefixes to be redistributed south */
8: required set<common.IPPrefixType> redistribute_south,
/** group name for evpn auto overlay */
9: required string bgp_group_name,
/** fabric prefixes to be advertised in rift instead of default */
10: required set<common.IPPrefixType> fabric_prefixes,
}
struct PartialEVPNEVI {
// route target per RFC4360
1: required CommunityType rt_target,
2: required RTDistinguisherType rt_distinguisher,
3: required RTDistinguisherType rt_type5_distinguisher,
5: required string mac_vrf_name,
6: required VNIType type5_vni,
}
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struct EVPNRRRole {
2: required common.IPv6Address v6_rr_addr_loopback,
3: required common.IPv6PrefixType v6_peers_allowed_range,
4: required map<MACVRFNumberType, PartialEVPNEVI> evis,
}
typedef i64 RTDistinguisherType
typedef i64 RTTargetType
typedef i16 MACVRFNumberType
typedef i16 VLANIDType
typedef binary MACType
typedef i16 UnitType
struct IRBType {
1: required string name,
2: required UnitType unit,
/// constant
3: required MACType mac,
/// contains address of the gateway as well
4: optional common.IPv6PrefixType v6_subnet,
/// contains address of the gateway as well
5: optional common.IPv4PrefixType v4_prefix,
}
typedef i32 VNIType
struct VLANType {
1: optional VLANIDType id,
2: required string name,
3: optional IRBType irb,
5: optional bool stretched = false,
6: optional bool is_native = false,
}
struct CEInterfaceType {
2: optional common.IEEE802_1ASTimeStampType moved_to_ce,
// we may not be able to obtain it in case of internal errors
3: optional string platform_interface_name,
}
typedef i64 CommunityType
struct EVPNEVI {
// route target per RFC4360
1: required CommunityType rt_target,
2: required RTDistinguisherType rt_distinguisher,
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3: required RTDistinguisherType rt_type5_distinguisher,
4: required string mac_vrf_name,
// fabric unique 24 bits VNI on non-stretch, otherwise unique across fabrics
5: required map<VNIType, VLANType> vlans,
6: required VNIType type5_vni,
}
struct EVPNLeafRole {
1: required set<common.IPv6Address> rrs,
2: required map<MACVRFNumberType, EVPNEVI> evis,
3: optional map<common.LinkIDType,
CEInterfaceType> ce_interfaces,
5: optional binary leaf_unique_lacp_system_id,
6: optional binary fabric_unique_lacp_system_id,
}
/// structure to indicate EVPN roles assumed and their variables for
/// external platform to configure itself accordingly. Presence of
/// according structure indicates that the role is assumed.
struct EVPNRoles {
1: required EVPNAnyRole generic,
2: optional EVPNRRRole route_reflector,
3: optional EVPNLeafRole leaf,
}
const common.TimeIntervalInSecType default_leaf_delay = 120
const common.TimeIntervalInSecType default_interface_ce_delay = 180
/// default delay before EVPNZTP FSM starts to compute anything
const common.TimeIntervalInSecType default_evpnztp_startup_delay = 60
A.4. auto_evpn_kv.thrift
This section contains the normative Auto-EVPN Analytics Thrift
schema.
include "common.thrift"
namespace py auto_evpn_kv
namespace rs models
/** We don't need the full role structure, only an indication of the node's basic role */
enum AutoEVPNRole {
ILLEGAL = 0,
auto_evpn_leaf_erb = 1,
auto_evpn_tof_gw = 2,
}
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enum KVTypes {
OUI = 1,
WellKnown = 2,
}
const i8 AutoEVPNWellKnownKeyType = 1
typedef i32 AutoEVPNKeyIdentifier
typedef i16 AutoEVPNCounterType
typedef i32 AutoEVPNLongCounterType
const i8 GlobalAutoEVPNTelemetryKV = 4
const i8 AutoEVPNTelemetryKV = 3
/** Per the according RIFT draft the key comes from the well known space.
Part of the key is used as Fabric-ID.
1st byte MUST be = "Well-Known"
2nd byte MUST be = "Global Auto-EVPN Telemetry KV",
3rd/4th bytes MUST be = FabricIDType
*/
struct AutoEVPNTelemetryGlobalKV {
/** Only values that the ToF cannot derive itself should be flooded. */
1: required set<AutoEVPNRole> auto_evpn_roles,
/** Established BGP peer count (for Auto-EVPN)
2: optional AutoEVPNCounterType established_bgp_peer_count,
/** Total BGP peer count (for Auto-EVPN)
3: optional AutoEVPNCounterType total_bgp_peer_count,
}
/** Per the according RIFT draft the key comes from the well known space.
Part of the key is used as MAC-VRF number.
1st byte MUST be = "Well-Known"
2nd byte MUST be = indicates "Auto-EVPN Telemetry KV",
3rd/4th bytes MUST be = MACVRFNumberType
*/
struct AutoEVPNTelemetryMACVRFKV {
/** Active CE interface count (up/up)
1: optional AutoEVPNCounterType active_ce_interfaces,
/** Total CE interface count
2: optional AutoEVPNCounterType total_ce_interfaces,
/** Active IRB interface count (up/up)
3: optional AutoEVPNCounterType active_irb_interfaces,
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/** Total IRB interface count
4: optional AutoEVPNCounterType total_irb_interfaces,
/** Local EVPN Type-2 MAC route count
5: optional AutoEVPNLongCounterType local_evpn_type2_mac_routes,
/** Local EVPN Type-2 MAC/IP route count
6: optional AutoEVPNLongCounterType local_evpn_type2_mac_ip_routes,
/** number of configured VLANs */
7: optional i16 configured_vlans,
/** optional human readable name */
8: optional string name,
/** optional human readable string describing the MAC-VRF */
9: optional string description,
}
Figure 3: Auto-EVPN Key-Value Thrift Schema
Appendix B. Auto-EVPN Variable Derivation
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use std::cell::{RefCell, RefMut};
use std::cmp::{max, min};
use std::collections::{BTreeMap, BTreeSet, HashMap};
use std::fmt::Debug;
use std::net::{Ipv4Addr, Ipv6Addr};
use std::str::FromStr;
use itertools::interleave;
use itertools::Itertools;
use rayon::slice::ParallelSliceMut;
use foundation::models::common::{FabricIDType, IPv6PrefixType};
use foundation::models::common::LevelType;
use foundation::models::common::HierarchyIndications;
use foundation::models::common::IPPrefixType;
use foundation::models::common::IPv4Address;
use foundation::models::common::IPv4PrefixType;
use foundation::models::common::IPv6Address;
use foundation::models::common::LEAF_LEVEL;
use foundation::models::common_services::ServiceErrorType;
use foundation::models::common_evpn::{DEFAULT_EVIS, DEFAULT_VLANS_PER_EVI,
DEFAULT_EVPNZTP_STARTUP_DELAY, DEFAULT_FABRIC_ID, DEFAULT_INTERFACE_CE_DELAY,
DEFAULT_LEAF_DELAY, EVPNAnyRole, EVPNLeafRole,
EVPNRoles, EVPNRRRole, UnitType};
use foundation::models::common_evpn::CEInterfaceType;
use foundation::models::common_evpn::CommunityType;
use foundation::models::common_evpn::EVPNEVI;
use foundation::models::common_evpn::IRBType;
use foundation::models::common_evpn::MACVRFNumberType;
use foundation::models::common_evpn::PartialEVPNEVI;
use foundation::models::common_evpn::RTDistinguisherType;
use foundation::models::common_evpn::VLANIDType;
use foundation::models::common_evpn::VLANType;
use foundation::models::common_evpn::VNIType;
use ILLEGAL_SYSTEM_I_D;
use NodeCapabilities;
use UnsignedSystemID;
Figure 4: auto_evpn_imports
/// indicates how many RRs we're computing in EVPN ZTP
pub const MAX_AUTO_EVPN_RRS: usize = 3;
/// indicates the fabric has no ID, used in computations to omit effects of fabric ID
pub const NO_FABRIC_ID: FabricIDType = 0;
/// invalid MACVRF number, MACVRFs start from 1
pub const NO_MACVRF: MACVRFNumberType = 0;
/// unique v6 prefix for all nodes starts with this
pub const AUTO_EVPN_V6PREF: &str = "FD00:A1";
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/// how many bytes in a v6pref for RRs
pub const AUTO_EVPN_V6PREFLEN: usize = 8 * 3;
/// unique v6 prefix for route reflector purposes starts like this
pub const AUTO_EVPN_V6RRPREF: &str = "FD00:A2";
/// unique v6 prefix for type-5 purposes starts like this
pub const AUTO_EVPN_V6T5PREF: &str = "FD00:A3";
/// unique v6 prefix for IRB prefix purposes
pub const AUTO_EVPN_V6IRBPREF: &str = "FD00";
/// unique v6 prefix first byte for v6 IRB prefix purposes
pub const AUTO_EVPN_V6IRBPREFFIRSTBYTE: u8 = 0xA4;
/// unique v4 prefix for IRB purposes
pub const AUTO_EVPN_V4IRBPREF: &str = "10";
/// 3 bytes of prefix type and then we have fabric ID after that
pub const AUTO_EVPN_V6_FABPREFIXLEN: usize = 8 + 8 + 8 + 16;
/// per RFC magic
const RT_TARGET_HIGH: CommunityType = 0;
const RT_TARGET_LOW: CommunityType = 0;
/// first available VLAN number
pub const FIRST_VLAN: VLANIDType = 1;
// maximum vlan number one less than maximum to use as bitmask
pub const MAX_VLAN: VLANIDType = 4095;
/// constant VLAN shift
pub const FIRST_VLAN_SHIFT: VLANIDType = 16;
/// NATIVE VLAN number
pub const NATIVE_VLAN: VLANIDType = 1;
/// abstract description of VLAN properties for a derived VLAN
pub struct VLANDescription {
pub vlan_id: VLANIDType,
pub name: String,
/// can this VLAN be stretched across multiple fabrics
pub stretchable: bool,
pub native: bool,
}
/// maximum number of VLANs per MACVRF
pub const MAX_VLANS_PER_EVI: usize = 15;
pub type VLANStretchableType = bool;
pub type VLANNativeType = bool;
pub const EXTRATYPE5_RD_DISTINGUISHER: u32 = 0xffff_ffff;
/// high bits of type 5 VNI
const TYPE5VNIHIGH: VNIType = 0x0080_0000;
/// bitmask for type 2 VNI
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const TYPE2VNIMASK: VNIType = 0x00ff_ffff ^ TYPE5VNIHIGH;
/// random seeds used in several algorithms to increase entropy
pub const RANDOMSEEDS: [u64; 4] = [
27008318799u64,
67438371571,
37087353685,
88675895388,
];
Figure 5: auto_evpn_const_structs_type
pub(crate) fn auto_evpn_sids2rrs(mut v: Vec<UnsignedSystemID>) -> Vec<UnsignedSystemID> {
v.par_sort_unstable();
let r = if v.len() > 2 {
let mut s = v.split_off(v.len() / 2);
s.reverse();
interleave(v.into_iter(), s.into_iter()).collect()
} else {
v
};
r
}
Figure 6: auto_evpn_sids2rrs
pub(crate) fn auto_evpn_v62octets(a: Ipv6Addr) -> Vec<u8> {
a.octets().iter().cloned().collect()
}
Figure 7: auto_evpn_v62octets
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/// fabric prefixes derived instead of advertising default on the fabric to allow
/// for default route on ToF or leaves
pub fn auto_evpn_fid2fabric_prefixes(fid: FabricIDType) -> Result<Vec<IPPrefixType>, ServiceErrorType> {
vec![
(auto_evpn_fidsidv6loopback(fid, ILLEGAL_SYSTEM_I_D as _), AUTO_EVPN_V6PREFLEN),
(auto_evpn_fidrrpref2rrloopback(fid, ILLEGAL_SYSTEM_I_D as _), AUTO_EVPN_V6PREFLEN),
]
.into_iter()
.map(|(p, _)|
match p {
Ok(_) => Ok(
IPPrefixType::Ipv6prefix(
IPv6PrefixType {
address: auto_evpn_v62octets(p?),
prefixlen: AUTO_EVPN_V6PREFLEN as _,
})),
Err(e) => Err(e),
}
)
.collect::<Result<Vec<_>, _>>()
}
Figure 8: auto_evpn_fid2fabric_prefixes
/// local address with encoded fabric ID and system ID for collision free identifiers. Basis
/// for several different prefixes.
pub fn auto_evpn_v6prefixfidsid2loopback(v6pref: &str, fid: FabricIDType,
sid: UnsignedSystemID) -> Result<Ipv6Addr, ServiceErrorType> {
assert!(fid != 0);
let a = format!("{}{:02X}::{}",
v6pref,
fid as u16,
sid.to_ne_bytes()
.iter()
.chunks(2)
.into_iter()
.map(|chunk|
chunk.fold(0u16, |v, n| (v << 8) | *n as u16))
.map(|v| format!("{:04X}", v))
.collect::<Vec<_>>()
.into_iter()
.join(":")
);
Ipv6Addr::from_str(&a)
.map_err(|_| ServiceErrorType::INTERNALRIFTERROR)
}
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Figure 9: auto_evpn_v6prefixfidsid2loopback
/// auto evpn V6 loopback for RRs
pub fn auto_evpn_fidrrpref2rrloopback(fid: FabricIDType,
preference: u8) -> Result<Ipv6Addr, ServiceErrorType> {
auto_evpn_v6prefixfidsid2loopback(AUTO_EVPN_V6RRPREF, fid, (1 + preference) as _)
}
Figure 10: auto_evpn_fidrrpref2rrloopback
/// auto evpn BGP router ID
pub fn auto_evpn_sidfid2bgpid(fid: FabricIDType, sid: UnsignedSystemID) -> u32 {
assert!(fid != 0);
let hs: u32 = ((sid & 0xffff_ffff_0000_0000) >> 32) as _;
let mut ls: u32 = (sid & 0xffff_ffff) as _;
ls = ls.rotate_right(7) ^ (fid as u32).rotate_right(13);
max(1, hs ^ ls) // never a 0
}
Figure 11: auto_evpn_sidfid2bgpid
/// route target bytes are type0/0 and then add EVI
pub fn auto_evpn_evi2rt(evi: MACVRFNumberType) -> CommunityType {
let wideevi = (evi + 1) as CommunityType;
(RT_TARGET_HIGH << (64 - 8)) | (RT_TARGET_LOW << 64 - 16) |
((wideevi) << 17) |
((wideevi))
}
Figure 12: auto_evpn_evi2rt
/// type-5 VNI for an EVI
pub fn auto_evpn_fidevi2type5vni(fid: FabricIDType, evi: MACVRFNumberType) -> VNIType {
TYPE5VNIHIGH | auto_evpn_fidevivid2vni(fid, evi, 0)
}
Figure 13: auto-evpn_fidevi2type5vni
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/// type-2 VNI for a specific VLAN
pub fn auto_evpn_fidevivid2vni(fid: FabricIDType, evi: MACVRFNumberType, vlanid: VLANIDType) -> VNIType {
let rfid = fid as i32;
let revi = evi as i32;
let rvlan = vlanid as i32;
// mask out high bits, VNI is only 24 bits
TYPE2VNIMASK &
(
rfid.rotate_left(16) ^
revi.rotate_left(12) ^
rvlan
)
}
Figure 14: auto_evpn_fidevivid2vni
/// maximum VLANs per EVI supported by auto evpn when deriving
pub fn auto_evpn_vlan_description_table<'a>(vlans: usize)
-> Result<&'a [(VLANIDType, VLANStretchableType, VLANNativeType)], ServiceErrorType> {
// up to 15 vlans can be activated
const VLANSARRAY: [(i16, bool, bool); MAX_VLANS_PER_EVI] = [
(NATIVE_VLAN, true, true, ),
(FIRST_VLAN_SHIFT, true, false, ),
(FIRST_VLAN_SHIFT + 1, true, false, ),
(FIRST_VLAN_SHIFT + 2, true, false, ),
(FIRST_VLAN_SHIFT + 3, false, false, ),
(FIRST_VLAN_SHIFT + 4, false, false, ),
(FIRST_VLAN_SHIFT + 5, false, false, ),
(FIRST_VLAN_SHIFT + 6, false, false, ),
(FIRST_VLAN_SHIFT + 7, false, false, ),
(FIRST_VLAN_SHIFT + 8, false, false, ),
(FIRST_VLAN_SHIFT + 9, false, false, ),
(FIRST_VLAN_SHIFT +10, false, false, ),
(FIRST_VLAN_SHIFT +11, false, false, ),
(FIRST_VLAN_SHIFT +12, false, false, ),
(FIRST_VLAN_SHIFT +13, false, false, ),
];
if vlans > VLANSARRAY.len() {
return Err(ServiceErrorType::INVALIDPARAMETERVALUE)
}
Ok(&VLANSARRAY[..vlans])
}
Figure 15: auto_evpn_vlan_description_table
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/// delivers the vlan description that can be used to generate vlans for a
/// specific fabric ID and a MACVRF number
pub fn auto_evpn_fidevivlansvlans2desc(fid: FabricIDType, macvrf: MACVRFNumberType,
vlans: usize) -> Vec<VLANDescription> {
assert!(NO_MACVRF != macvrf);
// abstract description of derived VLANs
let vlan_table = auto_evpn_vlan_description_table(vlans)
.expect("vlan table in AUTO EVPN incorrect");
let vlanshift = vlan_table
.iter()
.map(|(vl, _, _)| *vl as usize)
.max()
.expect("vlan table in AUTO EVPN incorrect")
.checked_next_power_of_two()
.expect("vlan table in AUTO EVPN incorrect");
assert!(vlan_table.len() < FIRST_VLAN_SHIFT as _);
vlan_table
.iter()
.map(move |(vid, stretch, native_)| {
let stretchedfid = if !stretch {
fid
} else {
NO_FABRIC_ID
};
let mut vlan_id = *vid ^ stretchedfid
.rotate_left(max(16, vlanshift as u32 + 8)) as VLANIDType;
// leave space for VLANs in the encoding
vlan_id ^= macvrf.rotate_left(vlanshift as _) as VLANIDType;
vlan_id %= MAX_VLAN;
vlan_id = max(1, vlan_id);
VLANDescription {
vlan_id: vlan_id as _,
name: format!("V{}", vlan_id),
stretchable: *stretch,
native: *native_,
}
})
.collect()
}
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Figure 16: auto_evpn_fidevivlansvlans2desc
/// IRB interface number.
/// fid/evi combination shifted up to not interfere with the VLAN-ID
/// and then add the VLAN-ID
pub fn auto_evpn_fidevivid2irb(fid: FabricIDType, evi: MACVRFNumberType, vid: VLANIDType) -> UnitType {
assert!(NO_MACVRF != evi);
let mut v = (fid as UnitType ^ evi.rotate_left(4) as UnitType) << (16 - FIRST_VLAN.leading_zeros());
v = 1 + v.wrapping_add(vid) % MAX_VLAN;
v % (UnitType::MAX - 1)
}
Figure 17: auto_evpn_fidevivid2irb
/// route distinguisher derivation
pub fn auto_evpn_sidfid2rd(sid: UnsignedSystemID, fid: FabricIDType, extra: u32) -> RTDistinguisherType {
// generate type 0 route distinguisher, first 2 bytes 0 and then 6 bytes
assert!(fid != NO_FABRIC_ID);
// shift the 2 bytes we loose
let convsid = sid as RTDistinguisherType;
let hs = ((sid & 0xffff_0000_0000_0000) >> 32) as RTDistinguisherType;
let mut ls: RTDistinguisherType = convsid & 0x0000_ffff_ffff_ffff;
ls ^= hs;
ls ^= (fid as RTDistinguisherType).rotate_left(16);
ls ^= extra as RTDistinguisherType;
ls
}
Figure 18: auto_evpn_sidfid2rd
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/// v4 subnet derivation
pub fn auto_evpn_v4prefixfidevividsid2v4subnet(v4pref: &str, fid: FabricIDType,
evi: MACVRFNumberType, vid: VLANIDType,
sid: UnsignedSystemID) -> Result<IPv4PrefixType, ServiceErrorType> {
assert!(NO_MACVRF != evi);
// fid can be 0 for stretched v4subnets
let mut sub = evi.to_ne_bytes().iter()
.fold((RANDOMSEEDS[0] & 0xff) as u8, |r, e| r.rotate_left(1) ^ e.rotate_right(1));
sub ^= fid.to_ne_bytes().iter()
.fold((RANDOMSEEDS[1] & 0xff) as u8, |r, e| r.rotate_left(2) ^ e.rotate_right(1));
sub ^= vid.to_ne_bytes().iter()
.fold((RANDOMSEEDS[2] & 0xff) as u8, |r, e| r.rotate_left(3) ^ e.rotate_right(1));
let subnet = sub % 254; // make sure we don't show multicast subnet
let _host = sid.to_ne_bytes().iter()
.fold(0u16, |r, e| r.rotate_left(3) ^ e.rotate_right(3) as u16);
let a = format!("{}.{}.{}.{}",
v4pref,
subnet,
0,
1,
);
Ok(
IPv4PrefixType {
address: Ipv4Addr::from_str(&a)
.map_err(|_| {
ServiceErrorType::INTERNALRIFTERROR
})?
.octets()
.iter()
.fold(0u32, |v, nv| v << 8 | (*nv as u32)) as IPv4Address
,
prefixlen: 16,
}
)
}
Figure 19: auto_evpn_v4prefixfidevividsid2v4subnet
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/// generic v6 bytes derivation used for different purposes
pub fn auto_evpn_v6hash(fid: FabricIDType, evi: MACVRFNumberType, vid: VLANIDType, sid: UnsignedSystemID)
-> [u8; 8] {
let mut sub = evi.to_ne_bytes().iter()
.fold(RANDOMSEEDS[3], |r, e| r.rotate_left(6) ^ e.rotate_right(4) as u64);
sub ^= fid.to_ne_bytes().iter()
.fold(RANDOMSEEDS[0], |r, e| r.rotate_left(6) ^ e.rotate_right(4) as u64);
sub ^= vid as u64;
sub ^= sid;
sub.to_ne_bytes()
}
Figure 20: auto_evpn_v6hash
pub fn auto_evpn_fidevividsid2v6subnet(fid: FabricIDType, evi: MACVRFNumberType,
vid: VLANIDType,
sid: UnsignedSystemID) -> Result<IPv6PrefixType, ServiceErrorType> {
assert!(NO_MACVRF != evi);
let sb = auto_evpn_v6hash(fid, evi, vid, sid);
let a = format!("{}:{:02X}{:02X}:{:02X}{:02X}:{:02X}{:02X}::1",
AUTO_EVPN_V6IRBPREF,
AUTO_EVPN_V6IRBPREFFIRSTBYTE,
sb[3] ^ sb[0],
sb[4] ^ sb[1],
sb[5] ^ sb[2],
sb[6],
sb[7],
);
Ok(IPv6PrefixType {
address: Ipv6Addr::from_str(
&a)
.map_err(|_| {
ServiceErrorType::INTERNALRIFTERROR
})?
.octets()
.to_vec(),
prefixlen: 64,
})
}
Figure 21: auto_evpn_fidevividsid2v6subnet
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/// MAC address derivation for IRB
pub fn auto_evpn_fidevividsid2mac(fid: FabricIDType, evi: MACVRFNumberType,
vid: VLANIDType, sid: UnsignedSystemID) -> Vec<u8> {
let sb = auto_evpn_v6hash(fid, evi, vid, sid);
vec![0x02,
sb[3] ^ sb[0],
sb[4] ^ sb[1],
sb[5] ^ sb[2],
sb[6],
sb[7],
]
}
Figure 22: auto_evpn_fidevividsid2mac
/// v4 loopback address derivation for every node in auto-evpn
pub fn auto_evpn_fidsid2v4loopback(fid: FabricIDType, sid: UnsignedSystemID) -> IPv4Address {
let mut derived = sid.to_ne_bytes().iter()
.fold(0 as IPv4Address, |p, e| (p << 4) ^ (*e as IPv4Address));
derived ^= fid as IPv4Address;
// use the byte we loose for entropy
derived ^= derived >> 24;
// and sanitize for loopback range
derived &= 0x00ff_ffff;
let m = ((127 as IPv4Address) << 24) | derived;
m as _
}
Figure 23: auto_evpn_fidsid2v4loopback
/// V6 loopback derivation for every node in auto-evpn
pub fn auto_evpn_fidsidv6loopback(fid: FabricIDType,
sid: UnsignedSystemID) -> Result<Ipv6Addr, ServiceErrorType> {
auto_evpn_v6prefixfidsid2loopback(AUTO_EVPN_V6PREF, fid, sid)
}
Figure 24: auto_evpn_fidsidv6loopback
#[allow(non_snake_case)]
pub fn auto_evpn_fid2private_AS(fid: FabricIDType) -> u32 {
assert!(fid != NO_FABRIC_ID);
// range 4200000000-4294967294
const DIFF: u32 = 4_294_967_294 - 4_200_000_000;
64496 + ((fid as u32) << 3) % DIFF
}
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Figure 25: auto_evpn_fid2private_AS
pub fn auto_evpn_fid2clusterid(fid: FabricIDType) -> u32 {
auto_evpn_fid2private_AS(fid)
}
Figure 26: auto_evpn_fid2clusterid
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
Wen Lin
Juniper Networks
10 Technology Park Drive
Westford, MA
United States of America
Email: wlin@juniper.net
Head, et al. Expires 10 January 2022 [Page 36]
