Why Is EVPN Better Than VPLS?

As organizations increasingly seek robust and scalable network solutions, selecting between EVPN and VPLS becomes crucial. Both technologies provide Layer 2 network extension capabilities, but they do so in distinct ways and offer different advantages. This article will delve into the definitions of EVPN and VPLS and compare their respective features to help you understand the key differences and benefits of each technology.

What Is VPLS

VPLS is an MPLS-based Ethernet solution that facilitates point-to-multipoint (P2MP) Layer 2 VPN connectivity over a public network. In a typical VPLS setup, users situated in various locations can communicate with each other through different Provider Edges (PEs). For users, a VPLS network appears as a Layer 2 switched network, providing communication capabilities similar to those of a traditional LAN.

As businesses grow and demand more flexible office environments, applications like VoIP, instant messaging, and teleconferencing are becoming increasingly common, necessitating robust end-to-end (E2E) data communication. Traditional technologies like ATM and Frame Relay, which only support point-to-point (P2P) connections, are often costly and complex. In contrast, MPLS VPNs offer a more efficient solution with easier configuration and flexible bandwidth management.

While traditional MPLS Layer 2 VPNs, such as VPWS, lack point-to-multipoint (P2MP) capabilities, MPLS Layer 3 VPNs can provide P2MP services but require high routing performance. VPLS addresses these challenges by combining the advantages of Ethernet and MPLS, delivering a comprehensive solution for multipoint communication. It effectively emulates LAN functionality, enabling seamless interaction across different LANs through MPLS networks.

Benefits

VPLS offers several advantages:

• It leverages the carrier’s IP infrastructure, which helps lower construction costs.

• It retains Ethernet’s high-speed performance.

• It allows seamless communication over Ethernet links, whether they are part of WANs or LANs, facilitating rapid and flexible service deployment.

• It reduces the need for carriers to configure and manage routing policies, thereby decreasing operational expenses.

What Is EVPN

EVPN is a network technology used to extend Layer 2 and Layer 3 connections between different networks. It leverages BGP to distribute MAC address information, allowing for efficient and scalable Ethernet connectivity across multiple sites. EVPN supports both MPLS and VXLAN , providing enhanced flexibility and scalability.

Benefits

EVPN provides several key advantages:

Enhanced Link Utilization and Transmission Efficiency: EVPN supports load balancing, optimizing network resource usage and reducing network congestion.

Lower Network Resource Usage: By implementing route reflectors (RRs) on the public network, EVPN reduces the number of logical connections needed between Provider Edges (PEs). Additionally, EVPN allows PEs to use locally cached MAC addresses to handle ARP requests from connected sites, thereby cutting down on unnecessary broadcast ARP messages.

EVPN vs VPLS: Similarities and Differences

When comparing EVPN and VPLS, it is critical to understand their similarities and differences. The similarities and differences are listed below:

Similarities

Both EVPN and VPLS are Layer 2 VPN technologies designed to extend Ethernet networks across multiple locations. Their primary goal is to provide seamless connectivity, allowing remote sites to operate as if they were on the same local network. This functionality is vital for organizations that require consistent network services across geographically dispersed areas.

Differences

EVPN and VPLS share similar objectives, but their methodologies and features differ significantly. Here’s a breakdown of the primary distinctions between them:

• Control Plane: EVPN employs BGP for its control plane, whereas VPLS relies on LDP or RSVP-TE . BGP offers superior resource efficiency and quicker convergence compared to LDP and RSVP-TE.

• Scalability: EVPN is designed to handle a large number of endpoints efficiently, making it ideal for expansive data center networks and cloud environments. Although VPLS is also scalable, it may not perform as effectively in very large-scale implementations.

• Configuration: Configuring EVPN is generally simpler and more straightforward than setting up VPLS. EVPN requires less configuration and can be deployed rapidly. In contrast, VPLS often demands more complex configuration, particularly concerning its control plane management.

• Layer 3 Connectivity: EVPN supports both Layer 2 and Layer 3 connectivity, allowing it to extend IP networks across different systems. On the other hand, VPLS is limited to Layer 2 connectivity only. This makes EVPN more versatile for organizations needing to integrate various sites or data centers with IP connectivity.

Addressing VPLS Limitations with EVPN

EVPN addresses several limitations of traditional L2VPNs, such as VPLS:

• Load Balancing Limitations: VPLS does not support traffic load balancing in multi-homing scenarios.

• High Resource Usage: VPLS requires all Provider Edges (PEs) to be fully meshed, leading to high network resource consumption for establishing point-to-point (PW) links between every pair of PEs. Additionally, a large number of ARP messages are needed for MAC address learning, which consumes bandwidth and can overload CPU resources on remote sites.

How EVPN Addresses These Issues:

• Control Plane MAC Management: EVPN uses BGP extensions for MAC address learning and advertisement on the control plane, allowing efficient load balancing among EVPN routes with the same destination MAC but different next hops.

• Reduced Mesh Requirements: EVPN eliminates the need for a fully meshed network of PEs by using BGP and route reflectors to distribute EVPN routes. This reduces network complexity and signaling messages.

• Efficient Address Learning: EVPN enables PEs to learn local MAC addresses via ARP and remote MAC/IP addresses through advertisement routes. PEs cache this information locally, reducing network resource usage by avoiding unnecessary ARP broadcasts.

In summary, while both EVPN and VPLS aim to extend Layer 2 connectivity across wide areas, EVPN’s modern approach and advanced features often make it the superior choice for contemporary networking needs.

For organizations looking to leverage the advanced features of EVPN, the S5870-48T6BC is an excellent choice. It supports EVPN, offering robust performance and scalability to meet the demands of modern, large-scale network environments.

Conclusion

EVPN offers several advantages over VPLS. Its use of BGP for MAC address distribution, support for both MPLS and VXLAN, and advanced traffic management capabilities make it a superior choice for modern, large-scale, and dynamic network environments. While VPLS has been a reliable technology for Layer 2 network extension, EVPN’s advanced features and scalability make it the preferred option for organizations seeking to optimize their network infrastructure and address evolving business needs.