EVPN vs LISP: Key Differences for Campus Networks

EVPN and LISP are two technologies that play critical roles in modern campus networks. FS switches, which support EVPN, provide seamless integration for Layer 2 and Layer 3 services, emphasizing multi-tenancy and VXLAN overlays. LISP provides innovative solutions for IP address mobility and routing efficiency. Comparing these protocols is essential for optimizing campus network design, mobility management, and scalability.

What is EVPN?

Ethernet Virtual Private Network (EVPN) allows virtualized Ethernet communication between different network devices. It's commonly used in data centers and service provider networks to establish efficient and scalable connections. Compared to traditional Layer 2 VPNs like Virtual Private LAN Service (VPLS), EVPN offers key advantages. One major benefit is its support for multi-tenancy, enabling multiple tenants to use the same physical infrastructure while keeping their virtual networks isolated and secure.

EVPN improves resource efficiency and scalability over traditional Layer 2 VPNs. An EVPN-VXLAN campus network allows seamless connectivity between campuses, data centers, and public clouds by running Layer 2 networks over a Layer 3 underlay with a VXLAN overlay managed by the EVPN control plane. For quick network growth, a collapsed core design is ideal, making setup and maintenance easier. Additionally, EVPN multihoming offers redundancy from the access layer to the collapsed core using an L3 IP fabric, removing the need for Spanning Tree Protocol (STP) in the campus network.

Building on this, VXLAN-BGP-EVPN uses Border Gateway Protocol (BGP) as the routing protocol in the EVPN control plane. This allows for dynamic tunnel creation and enables smooth migration of virtual machines (VMs) across data centers without disrupting users. While both architectures offer scalable and flexible solutions, VXLAN-BGP-EVPN greatly enhances automation and VM mobility, making it ideal for data centers that require constant and dynamic connectivity.

What is LISP?

The Locator/Identifier Separation Protocol (LISP) decouples the location and identifier of network hosts, facilitating the movement of VMs across subnets without altering their IP addresses. This innovative protocol introduces a new architectural framework that redefines traditional IP addressing by establishing two distinct namespaces. Endpoint Identifiers (EIDs) are designated for end hosts, while Routing Locators (RLOCs) are assigned to routers in the global routing system. This separation enhances routing efficiency and supports seamless mobility across diverse networks, making it particularly beneficial for dynamic environments where hosts frequently change locations. Additionally, LISP improves scalability and simplifies network management by enabling flexible address allocation and routing strategies.

EVPN vs LISP: Differences in Application Scenarios and Network Performance

EVPN vs LISP: Mobility and Endpoint Roaming

LISP is often favored in campus networks due to its strong mobility management. As organizations shift to Wi-Fi-only infrastructures or adopt Wi-Fi-first strategies, managing endpoint mobility becomes crucial. LISP performs well in environments where endpoints, such as user IP and MAC addresses, frequently switch between access points.

In contrast, EVPN, which was initially developed for data centers, also supports mobility but has certain limitations. Each VXLAN Tunnel Endpoint (VTEP) in EVPN needs to track all endpoints within the Virtual Routing and Forwarding (VRF) instances it manages. When an endpoint moves to a different VTEP, control plane messages are exchanged to update the network, which can create additional overhead in highly dynamic environments like campuses with numerous mobile devices.

EVPN vs LISP: Control Plane and Scaling

LISP offers efficient scalability and mobility optimizations. It can operate on lower-end, resource-constrained switches, making it ideal for networks with frequent endpoint changes. LISP’s control plane separates the routing locator (location) from the endpoint identifier (identity), making it suitable for high-churn environments.

EVPN, built on BGP, is highly capable but depends on a converged network infrastructure. When endpoints move, EVPN floods control plane traffic, which may strain the network, especially in mobility-heavy environments. Although EVPN can handle a large volume of updates (up to 400,000 per day), it can encounter challenges in environments with excessive endpoint movement.

EVPN vs LISP: Latency and MAC Moves

Both LISP and EVPN are designed to reduce latency during endpoint roaming. When a network interface card (NIC) moves from one access point to another, EVPN initiates the MAC move procedure once the NIC appears at the new location, ensuring traffic is forwarded with minimal disruption.

LISP operates similarly, notifying the network that the MAC address is now reachable through a different egress switch. Latency spikes during roaming are generally not caused by MAC moves alone; other factors, such as buffering, may also contribute to delays.

How to Choose for Your Campus Networks?

The table below summarizes the key differences between LISP and EVPN in campus environments, focusing on scalability, network segmentation, and performance, providing a quick comparison of their functions and benefits in such networks.

Recommended FS Products for EVPN-VXLAN Implementation

For FS products, if you're looking to implement an EVPN-VXLAN campus network, specifically VXLAN-BGP-EVPN, you’ll need FS switches that support EVPN at the hardware level, such as the S5800 and S5850 series. Additionally, you should purchase license #100590 separately to enable advanced features. The Basic Layer 3 functions come with the switch at no extra cost and are valid permanently. However, to unlock advanced features like MPLS and VXLAN-BGP-EVPN, license #100590 is required, and it too is valid forever.