EVPN is one of the most popular control planes in today’s networks as it just not only provides Layer 2 services but also can provide Layer 3 VPN as well.

When it was first introduced, came with the MPLS data plane but after that EVPN VXLAN became the most commonly used coupled technology, especially in the Datacenter networks.

In this post, we will look at some basics of MPLS vs VXLAN data planes in EVPN deployments.

EVPN MPLS

Let’s look at EVPN MPLS first.

It was first introduced in RFC 7432, BGP MPLS-Based Ethernet VPN.

In EVPN, MAC Learning between the PE devices happens not in the data plane (In VPLS it is in the data plane), but in the control plane.

Control-plane learning offers better control over the MAC learning process, for example, you can restrict what to advertise on which device, and also you can apply better policy as the BGP is our control plane in EVPN.

In fact, it is MPBGP- Multi-Protocol BGP, similar to IP VPNs, as it was described in RFC 4364.

In EVPN, PE devices advertise the MAC addresses learned from the CE devices, which are connected to them, along with an MPLS label to the other PEs, over the MP-BGP control plane.

Control-plane learning enables load balancing of traffic to and from CEs that are multihomed to multiple PE devices.

This is, in addition, to load balancing across the MPLS core network via multiple LSPs  – Label Switched Paths, between the same pair of PE routers.

In other words, it allows CE devices to connect to multiple active points of attachment.

It also improves convergence times in the event of link or node failures.

EVPN VXLAN

RFC 8365, A Network Virtualization Overlay Solution Using Ethernet VPN (EVPN) is covering the VXLAN data plane for the EVPN control plane.

In fact, this RFC is not only for the VXLAN but it covers a couple more data planes as well.

It specifies how Ethernet VPN (EVPN) [RFC7432] can be used as a Network Virtualization Overlay (NVO) solution and explores the various tunnel encapsulation options over IP and their impact on the EVPN control plane and procedures.

It basically covers, VXLAN, NVGRE, and GENEVE data-plane mechanisms.

Many Datacenter operators, if not all, don’t want to deploy MPLS in their networks.

Traditionally VXLAN from day one was targeted for the Datacenters, and the DC operators deployed in with or without control planes.

They shared the good experiences with them, and today it became the defacto data plane for the data center networks.

It is used in many campus networks as well.

And even we are seeing some vendor preparatory solutions, such as Cisco’s SDA – Software-Defined access, which uses VXLAN for the Campus or DC networks, as a data plane.

VXLAN is not even used together with the EVPN control plane, but for example in the Cisco’s SDA solution, LISP – Locator and Identity Separation Protocol are used together with it.

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