What are the Benefits of a Switch with EVPN and MLAG Functionality?

NADDOD Adam Jan 13, 2023

With the development of virtualization and cloud computing technologies, the performance requirements of switches are getting higher and higher, requiring switches with greater throughput to forward data and newer technologies to provide higher reliability for data, which must also facilitate the management of network administrators. At this time, EVPN and MLAG technologies are gaining attention and have become two of the most talked about features in the data center class switch space. So what are EVPN and MLAG features? What are the benefits of a switch with EVPN and MLAG functionality?

What is EVPN Function?

EVPN (Ethernet Virtual Private Network), which was first defined by RFC7432, the full name of RFC is: BGP MPLS-Based Ethernet VPN, from the name, it is a BGP and MPLS-based L2 VPN. When EVPN was first proposed, it was also used as L2 VPN, which was called next generation L2 VPN, improving on the original VPLS (Virtual Private LAN Service). EVPN, as a control layer, can usually interface to three data layers, MPLS, PBB and NVO, where NVO (Network Virtualization Overlay), a classification that includes VXLAN (Virtual eXtensible LAN).

EVPN Technical Advantages

EVPN not only inherits the advantages of MP-BGP and VXLAN, but also provides new functions. EVPN has the following features.

(1) Simplified configuration: VTEP auto-discovery, VXLAN tunnel auto-establishment, and VXLAN tunnel and VXLAN auto-association are achieved through MP-BGP, eliminating the need for manual user configuration and reducing the difficulty of network deployment.
(2) Separate the control plane and data plane: the control plane is responsible for publishing routing information and the data plane is responsible for forwarding messages, which is a clear division of labor and easy to manage.
(3) Support symmetric IRB (Integrated Routing and Bridging): MP-BGP publishes both Layer 2 MAC addresses and Layer 3 routing information, and VTEP can perform both Layer 2 forwarding and Layer 3 routing. This not only ensures that traffic is forwarded using the optimal path, but also reduces broadcast traffic.

What is MLAG Function

MLAG is a cross-device link aggregation of two devices that together form an M-LAG dual-active system. The two switches negotiate with each other over the peering link to determine master and slave, and synchronize information in real time over the peering link so that if one link is disconnected (not the peering link), the entire network still works properly. If one switch fails, all data will be transmitted through the other switch.

MLAG Technology Advantages

MLAG technology, or cross-device link aggregation group, is a mechanism to achieve cross-device link aggregation, enabling link aggregation between multiple devices, thus increasing link reliability to the device level and forming a dual-active system.

Benefits of a Switch with EVPN and MLAG Functionality

EVPN uses the distributed aggregation function DRNI (Distributed Resilient Network Interconnect) to connect two physical devices to virtually become one device, using the virtual device as a VTEP (either a VTEP for Layer 2 forwarding only or an EVPN gateway). The reliability of the EVPN network can be improved by avoiding the impact of a single point of failure of the VTEP on the network.

MLAG technology allows all links to be utilized and does not cause network oscillation when a link outage causes a topology change; MLAG can be a LAG group of ports on multiple switches, where the peer device assumes that its LAG group is connected to the same peer device, allowing full utilization and non-stop forwarding of the links using the LAG feature.


EVPN and MLAG technologies can effectively isolate the LAN, guarantee data security and improve the efficiency of the switch. It is important for large data centers to guarantee the load balancing of each link to make the engine room run stably.