VxLAN Basic Concepts

Network Virtual Edge Node

NVE (network virtualization edge) is a network entity that realizes the function of network virtualization. After the packet is encapsulated and transformed by the NVE network entity, the virtual VxLAN network can be established between the NVE based on the three-layer basic network.

VxLAN Tunnel End Point

VTEP (VxLAN Tunnel End Point) is a switching device located at the edge of the site. It operates as a layer-2 device in the site network and a L3 device in the core network. It mainly provides two-layer interconnection between site networks. It completes the packet encapsulation from the site network to the core network, and the packet decapsulation from the core network to the site network.

Core network interface: the L3 interface on the edge device connected to the core network, namely Network Port.

Site internal interface: the L2 interface on the edge device connected to the internal device of the site, namely Internal Port.

VxLAN Session

VxLAN session is to establish the VxLAN tunnel through manual configuration or protocol negotiation, and associate VxLAN instance to form an effective forwarding instance between VTEPs. This instance is called VxLAN session. Data can only be forwarded if the vxlan session is valid.

EVPN

EVPN (Ethernet Virtual Private Network) is a L2 VPN technology. The EVPN technology uses the extended MP-BGP to spread the host information in the user network among different sites, and uses the control plane to replace the data plane to complete the cross-site MAC address learning in the user network.

VXLAN is just a data encapsulation protocol. It does not define control plane. MAC address learning between sites is completed by the traffic flooding of the traditional data plane. The biggest drawback of this method is that there is a lot of flooding traffic in the data center bearing network. In order to solve this problem, VXLAN introduces

EVPN as the control plane. By exchanging BGP EVPN routes between VTEPs, it realizes the auto discovery of VTEP and the mutual notification of host information, so as to avoid unnecessary data flooding.