What Is a VPN Concentrator?

A VPN concentrator is a centralized management system that is able to create, organize, and secure massive volumes of VPN tunnels concurrently. These are purpose-built for enterprise systems, authenticating potentially thousands of connections at once to provide employees access to company network resources. VPN concentrators make it easier for network admins to manage VPN access at scale while maintaining strong security standards.

How a VPN Concentrator Works

When an authenticated user attempts to connect to company resources via a VPN, a VPN concentrator will open an encrypted tunnel between the corporate network and the end user’s device. Beyond just supplying the tunnel itself, a concentrator will also assign the user’s device a unique IP address, a feature that security engineers can use for whitelisting connection IPs and enforcing access controls.

Traditional VPN solutions can only support a limited number of concurrent connections, which can bottleneck performance for large-scale enterprises. A VPN concentrator overcomes this issue, as it is able to manage thousands of connections at the same time, while automating many of the security tasks (verifying user identities and enforcing encryption standards) that teams would otherwise need to handle manually.

For businesses that provide access to a large number of remote employees, a VPN concentrator ensures everyone can access network resources without interruptions, latency issues, or potential security risks.

Why Use a VPN Concentrator?

VPN concentrators are a reliable, scalable, and security-first solution for enterprises that need to facilitate remote connections en masse. They have become particularly popular since the 2020 pandemic, as the movement toward remote or hybrid working systems has led to more employees than ever before needing to connect from different parts of the world.

Besides facilitating this international connectivity, here are some of the main benefits of using a VPN concentrator:

• Centralized Management: The centralized structure that a VPN concentrator offers helps to improve cybersecurity team visibility into all remote sessions, letting them configure and control connections from one single platform.
• Enhanced User Experience: By balancing incoming traffic and distributing it effectively, VPN concentrators are able to offer users a reliable level of performance.
• Reduced Operational Overhead: VPN concentrators are able to automate many routine security operations, decreasing the total number of tasks that engineers need to cover.

Main Functions of a VPN Concentrator

A VPN concentrator implements features that enhance cybersecurity and boost connectivity, providing an all-in-one system for remote access.

Here are some of the main functions a VPN concentrator offers:

• Secure Remote Access: Primarily, a VPN concentrator provides direct, encrypted access to a company’s corporate network, connecting employees who aren’t based locally.
• User Authentication: Concentrators use additional cybersecurity strategies, like multi-factor authentication or asking for credentials to verify the individuals trying to connect are who they say they are and are authenticated.
• Traffic Encryption: VPN concentrators encrypt all data that travels between an endpoint device and the central network, making use of industry-standard protocols to prevent hijacking.
• IP Address Assignment: VPN concentrators assign remote connections with virtual IP addresses that security teams can use to monitor activity or enforce device-specific access regulations.
• Allow Network Segmentation: Building upon unique IPs, VPN concentrators can segment networks to prevent users from moving laterally through the system. An assigned IP address may only be able to access the designated network resources permitted.
• Perform Identity Obfuscation: When providing a temporary virtual IP, the VPN concentrator hides the user’s real IP, protecting external parties from obtaining any information about the location or device being used.
• Manage Application Access: When all connections flow through a VPN concentrator, network administrators can clearly see which applications are used, helping to mitigate shadow SaaS.

With this balance of features, VPN concentrators help large-scale organizations maintain secure remote connectivity at scale.

VPN Concentrator Encryption Protocol Types

VPN concentrators use encryption protocols to ensure the data that passes through the remote tunnels remains fully encrypted. Different encryption protocol types exist because they each offer unique security features and performance potentials. For example, some encryption formats might be more rigorous but will require more processing power, lowering performance in some cases.

Here are some of the main VPN concentrator encryption protocols:

• PPTP/MPPE: Point-to-Point Tunneling Protocol uses Microsoft Point-to-Point encryption to secure VPN tunnels. As a legacy choice, many of the oldest providers once used this system. However, due to known vulnerabilities, this is now fairly obsolete.
• L2TP/IPsec: Layer 2 Tunneling Protocol provides stronger encryption than PPTP/MPPE and uses IPsec. As another legacy choice that’s been around for a significant period, this is a useful choice to connect devices via VPN that aren’t modern enough to support newer VPN protocols.
• IPsec: IPsec is a strong encryption protocol that is more efficient than legacy choices and is widely compatible with modern devices. It’s widely integrated and often used for site-to-site tunnels or stable remote access.
• SSL/TLS: Secure Sockets Layer and Transport Layer Security are browser-based protocols, making them useful if a user wants to connect to a network without downloading a VPN client. The flexibility of this option makes it a common choice for deployments that prioritize ease of access.

Depending on the specific requirements a business has, teams can select a protocol that delivers the right balance of compatibility, security, and performance for their remote workers.

The Downsides of a VPN Concentrator

While there are numerous benefits to using a VPN concentrator, there are some operational and cost considerations that may impact its suitability for business.

Here are the main cons to consider:

• Costly: A VPN concentrator is significantly more expensive than standard VPN solutions, requiring a sizable initial investment for the hardware and software needed to deploy the solution. A business may also need to contract specialized engineers who understand how to use and manage this technology, increasing costs even further.
• Bandwidth Limits: VPN concentrators have limited bandwidth. When a company scales, this total bandwidth might not be sufficient to cover the total demand across the system, leading to slow performance for end users.
• Centralized Point of Failure: One of the VPN’s biggest advantages for management, in that it is completely centralized, also leads to a central concern. If the system is completely centralized, then a security issue or system downtime will impact all remote employees who use the service.

Depending on the size of your organization, looking for an alternative solution that still offers a high degree of remote connectivity may be a better option.

Alternatives to a VPN Concentrator

VPN concentrators shine at scale, making it easy to manage potentially thousands of independent remote worker connections at once. However, the baseline security enhancements that VPNs provide are useful to businesses of any size, making alternative VPN options an important piece of security architecture to consider.

Here are some alternatives to a VPN concentrator that businesses can use:

• VPN client: A VPN client is an on-device software program that allows a user to connect to corporate resources. For smaller workforces, this approach is easy to configure and set up across employee devices. There is no need for advanced connection balancing or management, making this a low-effort system to access VPN capabilities.
• VPN router: A VPN router offers many of the same capabilities as a VPN concentrator but on a much smaller scale. It has similar foundational security systems but lacks the more advanced features like centralized identity verification. A VPN router is a good choice for businesses that have a limited number of remote employees.
• Site-to-site VPN: A site-to-site VPN is an always-on approach that connects two corporate networks. For example, two distinct business offices could use a site-to-site VPN to create a secure channel between their sites. Companies can use this to enhance intra-office connectivity, but it doesn’t do much in bringing remote workers into the secure network bubble.
• IPsec Encryption: Businesses can use IPsec encryption without using a full VPN concentrator to protect individual devices and connections to their networks. This is a security-first approach, as IPsec offers a high level of encryption but doesn’t offer any of the management systems, like load balancing, that concentrators would.