Collapsed Spine with EVPN Multihoming
Updated at Jan 14th 20251 min read
Traditional MLAG technology has been widely used in data center networks for link aggregation, but as networks scale, it begins to show limitations in flexibility and traffic management. To overcome these constraints and meet the demands of modern data centers, the Collapsed Spine architecture combined with EVPN Multihoming offers a more efficient solution.
This article explores the key differences and advantages of EVPN Multihoming over MLAG, and how it enhances the Collapsed Spine architecture to optimize network management efficiency in large-scale data centers.
What is EVPN Multihoming?
EVPN Multihoming is a technology that links a single endpoint device or server to the network through multiple connections, enhancing the reliability and redundancy of data center and enterprise networks.
It introduces the concept of Ethernet Segments, using various links to avoid the complexity of dedicated Peer Links required in traditional MLAG (Multi-Chassis Link Aggregation) solutions, thus simplifying the network topology.
This technology enables seamless traffic forwarding in case of link failures, enhancing the network's scalability and high availability. Based on standard protocols, this architecture enhances compatibility with diverse network devices and simplifies deployment, offering a more flexible and efficient solution for network redundancy.
What is Collapsed Spine?
The Collapsed Spine architecture streamlines traditional three-tier networks by merging the spine and leaf layers, reducing latency and increasing bandwidth.
This design ensures high availability and scalability, making it ideal for environments with high concurrency demands. When integrated with EVPN Multihoming, the Collapsed Spine architecture further enhances fault tolerance and utilizes distributed control planes to optimize performance and scalability across multi-data-center deployments.
EVPN Multihoming VS MLAG
As data center demands grow, traditional MLAG struggles to meet large networks' scalability and flexibility needs. EVPN Multihoming, with its distributed control plane and standard protocols, provides superior scalability, reliability, and compatibility.
Scalability
MLAG relies on physical links and stacking connections, limiting scalability, especially in large data centers and multi-facility environments where configuration and maintenance become complex.
EVPN Multihoming, based on BGP-EVPN and VXLAN standards, uses a distributed control plane to support flexible horizontal scaling without worrying about physical distance limitations, smoothly handling network growth.
Availability
Although MLAG provides link redundancy, it still relies on a single control plane, which can impact network stability in the event of a failure.
EVPN Multihoming eliminates single points of failure through a distributed control plane, ensuring high availability by automatically rerouting traffic, making it ideal for multi-tenant environments and large-scale cloud data centers.
Compatibility
MLAG is limited to vendor-specific protocols, which can hinder interoperability between devices from different vendors.
EVPN Multihoming, based on the BGP-EVPN standard, supports seamless interconnection of multi-vendor devices, avoiding vendor lock-in and simplifying deployment and expansion in heterogeneous environments.
Flexibility
MLAG's load balancing mechanism is relatively static, and recovery from link failures can be slow.
EVPN Multihoming, leveraging BGP, enables dynamic load balancing and active-active redundancy, allowing real-time path adjustments based on network topology and traffic conditions, particularly in environments that require efficient load distribution and traffic optimization.
Cross-Regional Deployment
MLAG is confined to a single data center, lacking support for cross-regional redundancy and scaling, with physical connections limited by facility distance.
EVPN Multihoming enables distributed architectures across multiple data centers and regions, addressing global network complexity and cross-regional redundancy needs.
Application of EVPN Multihoming
Collapsed spine architecture is used to its advantage in simplifying network structure and reducing the number of devices. By introducing EVPN Multihoming, this architecture not only improves network redundancy and fault tolerance but also better meets the demands of modern data centers.
In a Collapsed spine architecture, the spine devices simultaneously serve as both spine and leaf devices, simplifying the network design. Since ToR switches are typically Layer 2 devices and do not support VXLAN, they do not function as traditional leaf devices. Instead, the leaf functions are handled by spine devices.
To enhance network redundancy and fault tolerance, EVPN Multihoming connects the ToR switches to multiple spine switches. This allows traffic to automatically fail over to another spine device in case of a failure, ensuring network continuity. EVPN Multihoming not only addresses the vendor dependency issues of traditional MLAG but also provides standardized multihoming functionality, overcoming the limitations of traditional MLAG.
By adopting a distributed control plane, EVPN makes load balancing and redundancy link management between multiple Spine switches more efficient, improving bandwidth utilization. Unlike traditional MLAG, EVPN does not require centralized control and supports flexible expansion, accommodating more complex network needs.
Additionally, the interconnection between data centers is achieved through Layer 3 data center interconnection rather than traditional Layer 2 extensions, further optimizing the VXLAN network and enhancing the scalability and manageability of inter-data center connections.
How FS can Help
FS PicOS® data center switches fully support EVPN Multihoming technology and seamlessly integrate with the Collapsed Spine architecture, offering a highly redundant and flexible network solution.
These switches are equipped with the AmpCon-DC SDN Controller, which simplifies the automation of operations and configurations, significantly enhancing network efficiency and system stability.
For more information on EVPN Multihoming technology, contact FS Solutions for expert support and customised services.