Co-authored with Nicolas Breton, Product Manager Marketing, Cisco

In the era of Cloud-scale networking, network simplicity, agility and scale are essential.  Service Providers are currently expanding their Data Center footprint to offer on-demand virtualized network services. This is what the industry refers to as Central Office transformation. Consequently, SP networks have been evolving towards network fabrics that connect small/medium-sized Data Centers to large ones but the complexity of delivering end-to-end services has never been so high. This is mainly due to the number of protocols serving different purposes that accumulated over the past 10 years or so.

It's prime time for network simplification!

How can you make it simpler?

Instead of running multiple control planes, look for a unified one. But which protocol should you consider? EVPN is a control plane of choice in the Data Center, so expanding it across the network seems to make sense. EVPN provides scalability, optimal forwarding and avoids traffic floods. As such, EVPN can be used for all Data Center to Data Center, Data Center to WAN and any other connectivity to the Data Center. Having one single Control Plane extending from Data Center to Metro and WAN brings simplification to the networking stack.

What are EVPN benefits?

EVPN provides separation between the Data Plane and the Control Plane allowing for the use of different encapsulation mechanisms in the data plane while maintaining the same Control Plane. Cisco's implementation of EVPN supports different flavors, including EVPN VXLAN, EVPN MPLS and PBB EVPN.  It also supports MPLS Segment Routing transport, which is gaining strong traction with Service Providers & Enterprise customers.

How does it work?

EVPN uses Multi-Protocol Extensions to BGP (MP-BGP) to distribute Layer2 MAC or IP information. Therefore, EVPN can control Layer2 or Layer3 overlays and can be used to deliver Ethernet and IP VPN services removing some complexity at the control level.

Moreover, EVPN provides enhancements over existing technologies. First, it optimizes traffic load sharing with all active multi-homing, e.g. devices or servers can be dual homed with both paths actives and per flow load sharing. As the multi-homing all active capability is native to EVPN, no need for complex Multi Chassis LAGs (link aggregations) configurations.

EVPN limits flooding for unknown Unicast as it does not use flood and learn technology. The learning is all in the control plane allowing for more control and policy enforcement. EVPN is also performing ARP suppression, another optimization that reduces unnecessary traffic flooding in the network.

In the Data Center, EVPN enables optimal East-West and South-North traffic forwarding. It supports Integrating Routing and Bridging for inter subnet routing. It also supports MAC mobility, so VMs can be moved within or across Data Centers. As EVPN is multi-transport, it can run over VXLAN or Segment Routing and enables scalable services fabrics.

Cisco's EVPN solution can be deployed in the Data Center, at the DC Interconnect as well as in Metro/Core networks. For brownfield deployments, Cisco's EVPN solution comes with tools that provide seamless integration and interworking with existing technologies. EVPN is an industry standard as defined in IETF RFC's which Cisco has been contributing to.

EVPN's adoption is growing as Service Providers see the need and benefits of having a unifying overlay Control Plane.

If you're attending MPLS World Congress in Paris next month, do come and listen to Patrice Brissette's EVPN presentation on Thursday, 23rd at 2:20pm.