Ethernet Virtual Private Networks (EVPN) Tutorial

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1

Ethernet Virtual Private Networks (EVPN)for Data Center Interconnect and other Applications

Tutorial

2

Introduction

Ethernet VPN delivers next-generation business, cloud, video and mobile transport services, including those applicable to 5G, in a

way that ensures optimal customer experience by means of world class flexible, efficient and highly resilient services.

This tutorial goes through the market drivers, technology overview and key use cases of EVPN services.

3

Agenda 1. Ethernet VPNs and Market Drivers

2. EVPN Concepts and Service Interfaces

3. EVPN Use-Cases

4. Technology Deepdive

5. Network Virtualization Overlay with EVPN

6. Conclusion

Topics



4

Ethernet VPNs and Market Drivers

5

Ethernet VPN Service Revenues

• With more than $70B predicted by 2020, Ethernet technology and services continues to be a huge industry-wide source of revenue

• Significant growth in cloud infrastructure build-up

6

IP VPN Service Revenues

• > $30B by 2020, IP VPN services continue to be a key revenue source

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

2013 2014 2015 2016 2017 2018 2019 2020

Rev

enu

es (

$m

)

IPsec-based

MPLS-based

7

EVPN’s Competitive Advantage

• EVPN agility– Simplicity – One technology for today’s and future services

– Enables Scalable, Flexible and Seamless connectivity across the datacenter and WAN

Services

ELAN

ELINE

ETREE

L3 VPN

Traditional

VPLS, PBB-VPLS

PW

VPLS ETREE

RFC4364

Cloud and DCI*

Unified architecture for VPN and cloud based services

Cloud and DCI de-facto standard for seamless connectivity

Higher efficiency, scale, maximum flexibility and greater control

Evolution

EVPN

Networking technologies

8

Cloud-based Data Center Interconnect

• Data Center Interconnect (DCI) at L2/L3 extends connectivity between data centers and from the data center to end users

• Infonetics estimates that routers for DCI will make up between 5% and 10% of the overall router market over the next few years [Router and Switch Vendor Leadership – Global Service Provider Survey June 30, 2015, page 6]

IP/MPLS Network

E2E EVPN

Control plane (EVPN)Data plane

(VXLAN/MPLS)

Non SDN-enabled data

center

Data center network IP/MPLS WAN Data center network

HVM

HVM

SDN Controller

Route Reflector

CE

SDN-enabled data center

DC-GW DC-GW

PEPE

PE PE CE

e.g. VLAN



9

EVPN Concepts and Service Interface Overview

10

EVPN Concepts (ESI, E-Tag, EVI, …)

CE

PE

LAG

PE

EVI 1

EVI 1

EVI 1EVI 1

EVI 1

EVI 1 EVPN MAC/IP

BGP updates

PE

PE

LAG

CE

PEPE

Control Plane learningPEs Advertise MAC Addresses and Next Hops from connected CEs using MP-BGP

Data Plane learningDynamic or Static (Provisioned), Management Protocol

Customer Edge (CE)Host, Router or Switch

EVPN Instance (EVI)Identifies a VPN

Ethernet TagBroadcast or Bridge Domain in the EVI

Data Plane encapsulationMPLS or IP

Ethernet Segment Identifier (ESI)Identifies all links that connect a given CE to the PEs (ESIs are unique across the network)

All-Active ModeMultihomed, two or more active PEs

Single-Active ModeMultihomed, one active PE

11

EVPN Service Interface Overview

12

EVPN Technology Benefits

What requirements does EVPN address

• Support All-Active multi-homing

• Minimizes flooding of BUM traffic / improve Learning

• Improves convergence using aliasing

• Support optimized VM mobility

• Allows fine grained, policy driven control on route advertisement control

• Integrate with next generation of transport technologies (e.g. VXLAN/IP)

• Simplified deployment with a single VPN technology for L3 and L2 VPNs

How is EVPN better than today’s technology

• EVPN provides ability to program remote MAC-addresses in the control plane using BGP as the transport protocol

• Data plane learning is limited to PE-CE

• Protocol natively supports multi-homing, resiliency, MAC mobility and L3 aware inter-subnet routing features

• Supports integrated routing and bridging solution with MAC/IP reachability across different VLAN



13

EVPN Use Cases

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Application of Ethernet VPN Technology

EVPN Use Cases

• Next gen L2VPN technology for E-Line/E-LAN/E-Tree services

• DC Interconnect – for L2 or L3 service stretched between two DCs over WAN

• EVPN control-plane for VXLAN forwarding plane for L2 or L3 aware subnet overlay on IP networks (in DC or WAN)

Which customers are interested in EVPN and why

• Service providers that offer E-LAN / E-Line services– EVPN technology improves their service offering

– Operators can replace VPLS, VPWS with more efficient technology

• Data Center Builders – SPs, Enterprises, Content providers– EVPN allows multi-tenant L2 service stretch between DCs

– EVPN with VXLAN for L2 or L3 aware service stretch between VMs on a IP fabric DC

15

BBF TR-350 – Ethernet Services

• Specifies end-end architecture, equipment requirements and common set of feature options to support carrier Ethernet services using BGP MPLS based EVPN

• Promotes multi-vendor interoperability

• Supports the following Ethernet service capabilities:

– MEF Carrier Ethernet services ( E-LAN currently supported. E-Line and E-Tree work ongoing)

– Ethernet service capabilities required by RFC 7209 (e.g. multi-homing with All-Active, load balancing, policy)

– Multi-service broadband access and aggregation (TR-178)

• MEF defined service attributes are supported using BGP MPLS EVPNs

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EVPN Ethernet service overview

• Ethernet service traffic is tunneled over a packet network such as MPLS or IP

• Unicast, unknown unicast and multi-destination traffic is supported

• Remote MAC addresses are learnt using a control-plane protocol (MP-BGP) but local MAC addresses continue to be learnt using standard IEEE procedures

• CE treats multiple links connected to PE(s) as a LAG. It uses local hashing to map traffic flows onto links in the LAG

PE

LAG

PE

MP-BGP

PE

PE

RR

CE

MEF UNI

CEMEF UNI

CEMEF UNI

CE

MEF UNI

LAG

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Ethernet Private LAN service

• EVPN Port-based Service Interface is used

• Ethernet Segment is the entire UNI

• CE-VLAN configuration at customer sites does not need co-ordination with the service provider. VID is preserved across the network

PE

LAG

PE

IP/MPLS

Network

PE

PE

CE

MEF UNI

CEEthernet Segment

/ MEF UNICEMEF UNI

CE

MEF UNI

LAG

CE CEMEF UNIMEF UNI

EP-LAN 1

EP-LAN 2

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Ethernet Virtual Private LAN service

• EVPN service interfaces that are VLAN based are used

• Services can be multiplexed on a PE-CE link

• All to one bundling is not allowed

PE

LAG

PE

IP/MPLS

Network

PE

PE

CE

MEF UNI

CEEthernet Segment

/ MEF UNI

CE

MEF UNI

LAG

CE MEF UNI

EVP-LAN 1

EVP-LAN 2

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Ethernet Line service

• An EVI would have exactly two endpoints– Both Private Line and Virtual Private Line services are provided

• Supports all-active multi-homing

• Supports flow based load-balancing in the MPLS network

• New BGP extended community for layer 2 attributes– e.g. Control-word, MTU, multihoming

PE

LAG

PE

IP/MPLS

Network

PE

PE

CE

MEF UNI

CEEthernet Segment

/ MEF UNICEMEF UNI

CE

MEF UNI

LAG

EP-LINE 1

EP-LINE 2

20

Ethernet Tree service

• E-Tree is a bidirectional communication service between root and leaf nodes

• An E-Tree has the restriction that leaf nodes cannot communicate with each other

• Work is in progress at IETF to extend RFC 7432 to support E-Tree (draft-ietf-bess-evpn-etree)

• Both Ethernet Private Tree (EP-Tree) and Ethernet Virtual Private Tree (EVP-Tree) can be supported

• RFC 7432 may be used as-is to implement TR-221 (E-Tree*)

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EVPN for Data Center Interconnect

Benefits

• Seamless interconnect for DCI – L3 aware and L2 stretch between DCs

• Seamless workload migration - VM mobility across DCs

• Wide Applicability – Interconnects Native L2 or L3 and overlay DC technologies like VXLAN, MPLS in DC

IP/MPLS Network

BGP Control Plane based learning in the DC

BGP Control Plane based learning in the WAN

PE

PE

PE

PE

SDN Controller

EVPN/VXLANData Center network

LegacyData Center network

Data Center Site 1 Data Center Interconnect Data Center Site 2

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L2 or L3 VPNs over IP WAN

EVPN implemented on enterprise' edge routersVXLAN data plane over operator's IP WAN

Benefits

• Data Center / Enterprises buy Simpler IP connectivity in WAN– No need to buy expensive VPN service, depending on requirements (e.g. SLA)

– EVPN overlay is transparent to service providers

• VXLAN Tunnel Endpoints (VTEP) on enterprises’ WAN (CE) routers

EVPN-VXLAN

SP WANNetwork

PE

EVI1

EVI1

EVI1

EVI1

CorporateNetwork

EVPN MAC/IP

BGP updates

CEPE

PE PE

CE

CE

CECorporateNetwork

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L2 Peering Service

Benefits

• Allows policy driven peering relationship to clients

– Different types of peering relationships (public peering / private peering) with same infrastructure, driven by policies

• Supports explosive traffic growth and high availability

– Active/Active multi-homing with load balancing

– Each ASBR connecting with two peering switches improves availability

– Capability to do ARP/ND proxy

PE

PE

PE

PE

RR

ASBR

LAG

ASBR

LAG Peering providerIP/MPLS network

ISP 1network

ISP 2network

BGP signaling on WAN exchange MAC/IP routes

Peering handoffpoint

Peering handoffpoint

MP-BGP

24

EVPN Use-Cases in Next-Gen Applications

EVPN for GiLAN

• EVPN can be used over IP fabric of DC and WAN IP/MPLS network

• Many Gi-LAN virtualized VAS can be deployed in the packet core and chained as needed

• Virtualized VAS can be scaled up/down on demand and deployed in a redundant manner

• EVPN with VXLAN can support VM migration

• RR can be virtualized and deployed flexibly in the network

EVPN for IoT

• EVPN supports large number of endpoints as required by IoT

• Simple endpoint provisioning enables creating services that can be deployed cost-effectively

• Diverse access technologies can be translated to a simple Ethernet access to an EVPN Instance

• QoS over the core ensures that differentiated services can be created with the required QoE (Quality of Experience)

IoT GW

IoT GW

IoT GW

PE

PE

Transport network

CE

CEAccess 1(Zigbee)

Access 2(MACSec)

Access 3(3G/4G/LTE/Wi-Fi)

68o

68o

68o

Mobile Backhaul

SDN Controller

EVPN/VXLANData Center network

PGW VM

VM

VM

VM

VM

DC-GW

DC-GW

PE

IP/MPLS network

CE

CE

PE

PE

VPN1

VPN2

RR



25

Technology Deepdive

26

EVPN Route Types and Benefits

Route Usage Business Benefit

Ethernet A-D Route (Type 1) • Advertising Split-Horizon Labels• MAC Mass-Withdraw• Aliasing

Loop Avoidance Fast Convergence

MAC Advertisement Route (Type 2)

• Advertise MAC Address Reachability• Advertise IP/MAC Bindings

Policy control

Inclusive Multicast Route (Type 3)

• PMSI tunnel attribute• BUM flooding

Set up path for BUM traffic

Ethernet Segment Route (Type 4)

• DF Election for multi-homing Loop avoidance

IP Prefix Route(Type 5)

• IP route advertisement without host MAC

L3 Routing Integration

27

MAC Route

• Advertises host MAC (and host IP) reachability with “service label”

– Allows Control Plane based MAC learning for remote PEs

– Minimizes flooding across WAN

– Allows PE to do proxy-ARP for remote hosts locally

• IRB MAC address route has default GW extended community

– Used in VM motion when default GW of VM remains same

• If IRB MACs and IP are same across MH PEs, avoids flooding after node failure

ESI

RD

Ethernet Tag ID

MAC Address

IPv4 or IPv6 Address

Service tags (MPLS labels)

MAC reachability advertisement

Establishes Reachability

PE

PE

PE

PE (DF)

LAGLAG

IP/MPLSnetwork

MP-BGP signaling on WAN

CECE

PEs learn MACs on CE-PE link and advertise its reachability in EVPN MAC routes

EVPN MAC/IP

BGP updates

Single-Active ESI All-Active ESI

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Inclusive Multicast Route

• Allows PE to send BUM traffic from a CE on a VLAN in an EVI, to all the other PEs that span that VLAN in that EVPN instance

• Uses Existing MVPN defined constructs for signaling and transport– P2MP Tunnel: If advertising PE uses a P-Multicast tree for EVPN, the PMSI Tunnel attribute MUST

contain tree identity

– Ingres Replication: Route includes PMSI Tunnel attribute with Tunnel Type set to Ingress Replication and Tunnel ID as PE address

• Able to carry the traffic of more than one EVPN instance on the same tree using ’Aggregation’

IMET Route advertisement

Sets up path for BUM trafficPer VLAN per EVI

Ethernet TAG ID

RD

Originating PE IP Address

PE

PE

PE

LAGLAG

IP/MPLSnetwork

MP-BGP signaling on WAN

CECE

EVPN IMET

BGP updates

Single-Active ESI All-Active ESI

PE (DF)

RR

29

Unique EVPN Capabilities

Key Control Plane Features• All-Active Multihoming and Designated

Forwarder Election

• All-Active Multihoming and Split Horizon

• Aliasing for load balancing

• MAC Mass-Withdraw for fast convergence

• Default Gateway Inter-Subnet Forwarding

• ARP proxy for peer’s IRB address of a BD in an EVI

• MAC Mobility Extended Community

• ARP/ND Proxy and Unknown Unicast Flooding Suppression for remote hosts

EVPN Data Plane Options• MPLS or IP/GRE as transport for EVPN

• PBB-EVPN – PBB frames are encapsulated over MPLS similar to Ethernet

• VXLAN – VXLAN overlay network transport Ethernet frames over UDP/IP

30

Carrier Class scaling with EVPN

Control Plane

• Propagation of EVPN routes for a given VLAN/subnet is constrained by the provisioning of PEs

• Route Reflector infrastructure

• Use of RTC to limit EVPN route distribution to participating PEs

Data Plane

• The presence of a MAC address in the control plane does not imply that it must be installed in the forwarding plane

• PBB for EVPN can further ease MAC table sizes

31

PBB-EVPN Key Concepts (RFC 7623)

BMAC Control Plane learning• System BMACs are advertised by MP-BGP• ESI BMACs are advertised by MP-BGP

CMAC Data Plane learning• CMAC-local AC or CMAC to remote BMAC

mapping is learnt in the data plane

PBB-EVPN combines 802.1ah and EVPN• PEs have I-components mapped to B-

components (EVIs)• Reduces the number of MACs in EVPN by

aggregating CMACs with BMACs

Used for layer-2 EVPN networks• All EVPN Multihoming functions are supported,

including Single-Active and All-Active• Per-ISID flooding tree are supported• The B-component EVI uses MPLS data plane

PE

LAG

PE

PE

PE

CE

MEF UNI

CE

MEF UNI

LAG

BMAC BGP

update

PBB MAC

Mapping

B-component

EVI 1

EVI 1EVI 1

EVI 1

ISID-1

IP/MPLSnetwork

32

Integrated Routing and Bridging (IRB)

EVPN provides layer-2 and layer-3 services• Both services are provided through the same logical

AC to the customer• One VPN technology for both services, no need for

multiple protocols• VXLAN or MPLS data planes are possible

Required EVPN features• IP-prefix advertisement and inter-subnet forwarding• All-active multihoming for load balancing• Single-active multihoming for better determinism

Asymmetric IRB model: draft-ietf-bess-evpn-inter-subnet-forwarding

Symmetric IRB model: draft-ietf-bess-evpn-prefix-advertisement

PE

PE

PE

CECE

MEF UNI

LAG

EVPN MAC/IP

updates

IP/MPLSnetwork

MEF UNI

EVI 3EVI 2

EVI 1

VRF

EVI 3

EVI 2

EVI 1

EVI 3

EVI 2

EVI 1

LAG



33

Network Virtualization Overlay with EVPN

34

` ` `` ` `

Traditional Datacenter Design

Challenges:• MAC Address Explosion• VLAN ID Limitations• Subnet alignment with L2 domains

Result in:• Asset isolation• Complex compute migrations• Complex provisioning of new endpoints• Vendor lock within the DC• Constrained growth / moves within a POD

L2 Networking- VLAN Separation- xSTP or MC-LAG- Vendor specific L2

enhancements

VM Move / Balance Domain- Rows or Rack

WANNetwork

35

Data Center network direction

• Data Center networks will have to increasingly adapt virtualized workload and on going enterprise transition to private and hybrid clouds

• DC architecture is changing from traditional L2 to Spine – Leaf

• Infonetics Research report on “Data Center Strategies” Sept. 2014 provides preferred DC fabric features. They are:– High speed

– Automatically adjust to VM mobility

– Low latency

– Multipath connectivity

• Virtual Machines per servers are increasing by 50% in 2 years

• Data Center Interconnect mechanism has to support: Bridging, Routing and Overlay

36

` ` ` ` ` `

Combination of EVPN and VXLAN for scalable DC

VXLAN (RFC 7348)• Scalable IP tunneling encapsulation that allows

multi-tenancy (VNI)• Uses UDP source port to provide entropy and

ECMP in the IP fabric• De-facto standard in server NICs and DC gateways

BGP-EVPN (RFC 7432)• Provides massive control plane scalability• Auto-discovery of remote VTEPs• Advertising of MACs, IPs and IP prefixes• Cloud-optimized:• Mobility• Protection• Proxy-ARP/ND• Inter-subnet forwarding

WANNetwork

MAC

Pay

load

MAC

IP

UDP

VXLAN

MAC

Pay

load

MAC

Pay

load

DCNetwork

VMTenant 2

EVI 1

EVI 2

EVI 1

EVI 2

VMTenant 1 VM

Tenant 2

VMTenant 1

Hypervisor

EVI 1

EVI 2

EVI 1

EVI 2



37

Conclusion

38

EVPN standardization highlights

• RFC 7209: Requirements for Ethernet VPN (EVPN)

• RFC 7432: BGP MPLS Based Ethernet VPN: RFC 7432

• RFC 7623: Provider Backbone Bridging Combined with Ethernet VPN (PBB-EVPN)

• draft-ietf-bess-evpn-vpws: VPWS support in EVPN

• draft-ietf-bess-evpn-etree: E-TREE Support in EVPN & PBB-EVPN

• draft-ietf-bess-evpn-inter-subnet-forwarding: Integrated Routing and Bridging in EVPN

• draft-ietf-bess-evpn-prefix-advertisement: IP Prefix Advertisement in EVPN

• draft-ietf-bess-evpn-overlay / draft-ietf-bess-dci-evpn-overlay: EVPN Overlay networks (interconnect to WAN services)

• BBF TR-350: Ethernet Services using BGP MPLS Based EVPN

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Summary

• EVPN is a versatile technology that overcomes the limitations of VPLS and supports multiple deployment options

• EVPN’s architectural principles are similar to the well deployed BGP/MPLS IP VPNs. It can use multiple data plane technologies such as MPLS, VXLAN and IP

• EVPN provides several key benefits (i.e. integrated services, network efficiency, design flexibility, simplified provisioning) to Service Providers and simplifies their network while allowing to offer advanced services to customers. Further it reduces OPEX

• Data Centers interconnected using EVPN support business continuity, disaster prevention and workload mobility

• Cloud computing and NFV are shifting DC networks to SDN-based DCs where VXLAN and EVPN provide the required capabilities

40

Contributors

• Guiu Fabregas – Nokia, Editor

• J. Rao Cherukuri – BBF Distinguished Fellow

• Sachin Natu – Juniper

• Ravi Shekhar – Juniper



41Thank you

Getting InvolvedAccelerate new opportunities for your company by actively participating in the work of the BBF

More at broadband-forum.org

[email protected]

42

AbbreviationsARP – Address Resolution Protocol

AS – Autonomous System

BBF – Broadband Forum

BGP – Border Gateway Protocol

B-MAC – Provider Backbone MAC

CE – Customer Edge device

C-MAC – Customer/Client MAC

DF – Designated Forwarder

DWDM – Dense Wave Division Multiplexing

EVI – EVPN Instance

ES – Ethernet Segment

ESI – Ethernet Segment Identifier

FRR – Fast ReRoute

IETF – Internet Engineering Task Force

IP/MPLS – Internet Protocol / Multi Protocol Label Switching

43

Abbreviations (2)IRB – Integrated Routing and Bridging

I-SID – Service Instance Identifier

L2VPN – Layer 2 Virtual Private Network

LLDP – Link Layer Discovery Protocol

MP-BGP – Multiprotocol BGP

MPLS – Multiprotocol Label Switching

MTU – Maximum Transmission Unit

ND – Neighbor Discovery

NFV – Network Function Virtualization

NLRI – Network Layer Reachability Information

P2MP – Point to Multipoint

P2P – Point to point

PBB – Provider Backbone Bridging

PE – Provider Edge (Node)

PMSI – Provider Multicast Service Interface

PW - Pseudowire

44

Abbreviations (3)RD – Route Distinguisher

RFC – Request For Comments

RT – Route Target

SDN – Software Defined Networks

SLA – Service Level Agreement

STP – Spanning Tree Protocol

TR – Technical Report

UNI – User to Network Interface

UDP – User Datagram Protocol

VID – VLAN ID

VLAN – Virtual Local Area Network

VPLS – Virtual Private LAN Service

VPN – Virtual Private Network

VRF – Virtual Routing and Forwarding

VTEP – VXLAN Tunnel Endpoint

VXLAN – Virtual eXtensible Local Area Network

4545

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Ethernet Virtual Private Networks (EVPN) Tutorial

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