ELI5: What is a VPN concentrator?

If a VPN is a secret tunnel, a VPN concentrator is the big tunnel station where hundreds of tunnels all meet in one place. It is a dedicated machine built to handle lots of secure connections at the same time.

Definition

A VPN concentrator is a dedicated network device designed to terminate and manage large numbers of simultaneous VPN connections. Unlike a general-purpose router or firewall that may support VPN as one of many functions, a VPN concentrator is purpose-built for high-throughput VPN termination, providing centralized authentication, encryption, and access policy enforcement for remote users connecting to a corporate network.

Key Details

  • Supports site-to-site and remote-access VPN termination at scale
  • Performs encryption/decryption offloading, preserving performance on other network devices
  • Integrates with RADIUS, LDAP, or Active Directory for user authentication
  • Supports protocols including IPSec, SSL/TLS (SSL VPN), L2TP, and OpenVPN
  • Always-on VPN solutions often use concentrators as the central termination point

Connections