EVPN Multi-Homing and MLAG: Key Differences
Mar 01, 20251 min read
As modern data centers and large enterprise networks require greater availability and redundancy, technologies like MLAG (Multi-Chassis Link Aggregation) and EVPN Multihoming have become essential. While MLAG provides redundancy through device link aggregation, EVPN Multihoming offers more flexibility with its protocol-based multi-homing. This article compares the principles, mechanisms, and applications of both technologies, helping you choose the most suitable solution.
What Is MLAG？
As network scales grow, the limitations of traditional stacking technologies become apparent. The single control plane creates a bottleneck, and centralized architectures struggle to meet the needs of medium-sized networks, especially with physical cable distance constraints. MLAG enables multi-device redundancy and coordination through logical links, overcoming traditional stacking limitations.
MLAG allows two or more switches to operate as a single unit when forming a link aggregation group. This enables uplinks from hosts to two switches for physical diversity, while only one bundled interface needs to be managed. Additionally, two switches can use MLAG to connect to another pair of switches, with all links forwarding traffic.
What Is EVPN-Multihoming?
EVPN Multi-Homing consists of multiple VXLAN Tunnel Endpoints (VTEPs) in a redundant backup group, which solves the problem of network interruption caused by a single point of VTEP failure and allows traffic load balancing among VTEPs. Evpn Multi-HOMing has excellent scalability and redundancy. This improves the reliability of the VXLAN access side.
EVPN Multihoming is a standards-based solution that enables All-Active server redundancy in data centers and enterprise networks.
The core concept of EVPN Multihoming is the introduction of Ethernet Segments (ES). In the BGP EVPN framework, an Ethernet Segment refers to a collection of multiple links that connect a single-end host or server to the EVPN VXLAN network. For example, a server can be connected to multiple VTEPs through multiple links, forming an Ethernet Segment. Additionally, different servers can connect to the VXLAN network via their respective link sets, with each set forming an independent Ethernet Segment.
Applications of MLAG
MLAG is ideal for smaller networks with limited budgets and traditional Layer 2 architectures without VXLAN or SDN overlays.
Traditional Dual-Homing in Data Centers
MLAG is ideal for active-active server and switch connectivity scenarios, providing link-level redundancy through cross-device link aggregation. In this setup, physical servers can connect to two switches via bonded dual network adapters, and storage devices can establish active-active connections, eliminating single points of failure. This configuration is straightforward and does not require extensive modifications to the existing Layer 2 network.
High Availability for Small and Medium-Sized Networks
In environments where complex overlay networks like VXLAN are unnecessary, MLAG offers a cost-effective redundancy solution by enabling load balancing across dual devices. It can serve as an active-active gateway for enterprise core switches or interconnect access-layer switches to improve uplink bandwidth utilization.
Applications of EVPN-Multihoming
EVPN Multihoming is ideal for VXLAN overlay networks requiring multipath redundancy, redundancy groups with three or more devices (e.g., multi-tier Spine-Leaf), and hybrid/multi-cloud architectures needing cross-vendor or cross-region coordination.
VXLAN Overlay Network Multi-Homing
EVPN Multihoming is specifically designed for VXLAN networks, allowing multiple VTEPs (such as in a Spine-Leaf architecture) to form redundancy groups. This addresses MLAG’s scalability limitations in VXLAN deployments. For example, in cloud data centers, it enables virtual machines to connect through multiple paths and supports distributed gateway deployment across multiple Leaf switches. This approach mitigates Peer-Link bandwidth bottlenecks and facilitates seamless upgrades.
Large-Scale Cloud Networks and Multi-Tenant Environments
EVPN Multihoming achieves MAC/IP synchronization through BGP route propagation, making it suitable for dynamic traffic load balancing in multi-tenant isolation scenarios and gateway redundancy across geographically distributed data centers (such as Active-Active DCI). It also enables fine-grained control over routing policies.
As an RFC-compliant solution, EVPN Multihoming supports interoperability across different vendors. For example, it enables redundancy groups consisting of Cisco Nexus and Arista switches and provides a unified control plane for multi-vendor Spine-Leaf architectures.
EVPN Multi-Homing vs. MLAG
EVPN Multihoming provides optimal reliability through its distributed control architecture, supporting multi-device redundancy and excellent scalability. It is fully compliant with the BGP-EVPN standard, ensuring better cross-vendor interoperability. MLAG is widely used in data center networks because of its ability to enhance link reliability and simplify equipment maintenance.
Feature | Multihoming | MLAG |
Redundancy | Description: Multi-point redundancy, supports multiple devices, and has no central point of failure. | Description: Multi-device redundancy, avoids single-device failure. |
Rating: ⭐️⭐️⭐️⭐️⭐️ | Rating: ⭐️⭐️⭐️⭐️ | |
Reliability | Description: Distributed control eliminates single points of failure, offering optimal reliability. | Description: Link aggregation improves network reliability |
Rating: ⭐️⭐️⭐️⭐️⭐️ | Rating: ⭐️⭐️⭐️⭐️ | |
Scalability | Description: Theoretically unlimited scalability. | Description: Supports two devices. |
Rating: ⭐️⭐️⭐️⭐️⭐️ | Rating: ⭐️⭐️ | |
Manageability | Description: Based on standard protocols, relatively simplified management, but requires EVPN knowledge. | Description: Requires additional configuration of Peer Link and device synchronization protocols. |
Rating: ⭐️⭐️⭐️ | Rating: ⭐️⭐️⭐️ | |
Compatibility | Description: Based on BGP-EVPN standards, strongest compatibility. | Description: Vendor-specific implementation. |
Rating: ⭐️⭐️⭐️⭐️⭐️ | Rating: ⭐️️ | |
Application scenario | VXLAN Overlay Network Multi-Homing Access
Large-Scale Cloud Networks and Multi-Tenant Environments
Heterogeneous Vendor Device Hybrid Networking
Large data centers | Traditional Data Center Dual-Homing Access
Medium-sized enterprises or data centers |
How FS can Help
As networks continue to grow and cloud computing environments expand, EVPN Multihoming will become the main solution for high-availability networks due to its scalability, distributed architecture, and standardized nature. MLAG will remain valuable for medium-sized network needs.
FS provides 10G 25G 100G data center switches and supports both MLAG and EVPN multi-homing, which can meet the requirements of customers in multiple scenarios. PicOS® switches utilize the unified PicOS® and AmpCon-DC SDN Controller, automating operations, maintenance, and configuration, greatly enhancing data center efficiency and system stability.