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VXLAN—EVPN Overlay Overview


Spanning Tree Protocol (STP), multichassis link aggregation group (MC-LAG), and Transparent Interconnection of Lots of Links (TRILL) were some of the commonly used technologies in traditional data centers. However, as the data centers started to grow exponentially, these technologies were not able to scale to meet the requirements of data centers. To cater to these requirements, data center administrators started using orchestration tools such as VMware vCenter, VMware vCenter with NSX, OpenStack, and OpenStack with NSX plug-in to orchestrate the networking needs of the tenants that a data center serves. This approach meant that the data center might require additional plug-ins to configure VLANs and gateways or that you might need to make changes to the physical network topology, to accommodate a new tenant. Most of the current day data centers handle multiple customer groups, organizations, or tenants that require a new data center architecture that decouples the underlay network from tenant overlay networks. A Layer 3 Fabric underlay coupled with a Virtual Extensible LAN (VXLAN)–Ethernet VPN (EVPN) overlay solution that uses bare metal servers and/or virtual servers, or both Network Director for management enables data center and cloud operators to deploy much larger networks than that are otherwise possible with traditional Layer 2 Ethernet-based architectures.

Some of the major advantages that VXLAN—EVPN overlay networks provide are:

  • Scalability—Most enterprises accommodate their growth by increasing the use of cloud services, while others choose to deploy their own private and hybrid clouds. Service providers also must be able to be grow rapidly to have sufficient capacity to meet the demands of the enterprises. Today’s networks are often too rigid and difficult to change for scaling to meet the needs of large enterprises and service providers. But by using VXLAN—EVPN, data centers and cloud operators can have up to 16 million overlay networks in a cloud data center.

  • Operational efficiency—As enterprises expand geographically, the physical distance between the data centers and users also increases, which makes timely maintenance and application mobility a challenge. The VXLAN—EVPN solution enables network administrators to easily migrate applications within the data center and between data centers for business continuity so that they can maintain the data center without downtime, for effective load balancing.

  • High Performance—End users often experience poor response times and even outages of business-critical applications caused by bandwidth limitations and latency problems. Multi-pathing and control plane learning features, that are part of the VXLAN—EVPN solution, can optimize network traffic flows, rein in network faults, and ensure maximum utilization of bandwidth.