What Is A VPN Concentrator?

What Is A VPN Concentrator?

Updated: 08-18-2021

The world is rapidly changing, and many businesses are switching to working remotely. This necessitates well-established security protocols to ensure a seamless transition and that such businesses can continue to operate as usual.

For this reason, many businesses use Virtual Private Networks (VPNs) to secure their internal networks.

VPNs reduce the risk of cyberattacks by encrypting network traffic and protecting private data from prying eyes. Using a VPN protects your online identity from your Internet Service Provider (ISP), the government, and hackers.

A VPN router works just fine for individuals and small businesses. Large businesses, however, require a VPN concentrator to secure all VPN connections in multiple tunnels.

So what is a VPN concentrator, and why is it such an excellent security tool?

A VPN concentrator is a modified router that offers a more secure connection between different VPN servers. The main difference between a VPN concentrator and a VPN router is that a router is limited to a certain location and serves fewer people. In contrast, a VPN concentrator can serve many people from different locations.

Large companies with remote workers in varied locations use VPN concentrators to manage data flow between their users. Using commercial VPN providers may not be an option as each user will need to install different VPN software. Below are the main reasons large organizations use VPN concentrators:

  • All users can access organizational resources from their remote locations securely.
  • It can accommodate more users than a VPN router.


Investing in third-party security software can be expensive for large businesses and organizations. This article reveals how a VPN concentrator works and its significance in keeping organizational resources secure.

Here's what we'll discuss:

  • How does a VPN concentrator work?
  • Why should organizations invest in a VPN concentrator?
  • Which is the best VPN concentrator?
  • What are the cons of using a VPN concentrator?
  • Which VPNs offer the best concentrators?
  • Frequently Asked Questions About VPN Concentrators

How Does a VPN Concentrator Work?

Employees working remotely need to access their organization's resources securely. The installation of a VPN concentrator in an organization's internal network encrypts outgoing and incoming network traffic.

A VPN concentrator has dedicated software that supports a given number of VPN connections. It functions the same way as a regular VPN but is specifically built for large-scale companies. You can equate it to a VPN router that establishes multiple VPN tunnels.

It basically extends a VPN router's capabilities by creating and managing multiple remote connections. Each user has their own unique tunnel created and can access one network at the same time. The VPN concentrator assigns each user their own IP address and creates a unique network tunnel that they can use to connect to the server.

Basically, a VPN concentrator:

  1. Creates secure network tunnels.
  2. Allocates remote user's authentication to access a central server.
  3. Defines and arranges the parameters and permutations of the network tunnel.
  4. Encrypts and decrypts data received from users.
  5. Manages security keys associated with the VPN networks.
  6. Optimizes the data flowing through the various established tunnel connections.
  7. Manages incoming and outgoing traffic at each network endpoint.

Why Should Organizations Invest in a VPN Concentrator?

Investing in a VPN concentrator is essential for large organizations and businesses that want to keep their communication and data secure. A VPN router would be ideal for individuals and small businesses because the magnitude of tasks executed is less compared to large organizations.

Here is why a VPN concentrator will be a vital addition to your business:

Enhanced Security

All organizations value privacy and data security. Hackers or third parties can compromise data if the organization's internal network is not secure, putting the business at risk. To protect company data from hackers, malware, and third parties, using a secure private network is necessary.

Investing in a VPN concentrator provides secure creation of VPN networks within an organization. This makes it extremely difficult for hackers and third parties to infiltrate the private network.

Easy Access To Servers

One of the major pros of a VPN concentrator is that users can access the company's servers from their various remote locations. On the contrary, a VPN router is limited to a specific location and server.

Unlimited Access

An organization with a large team that needs access to the same resources will largely benefit from a VPN concentrator. This is because thousands of employees can easily access the company's network without using different VPN client software, affecting the quality of work and exposing the company's data to malicious parties.


Which Is The Best VPN Concentrator?

Vendors selling VPN concentrators base the price points on performance. The greater the performance, the higher the price, and vice versa.

The smaller models normally come with software-based implementations, while the larger ones are complex with dedicated encryption and decryption hardware.

Depending on the size of the business or organization, you'll need to consider important factors, such as load balancing, redundancy, and capacity requirements.

Load balancing: This is when several VPN concentrators are running in parallel. The process of configuring these devices to use a common public virtual IP address and share the session load is known as load balancing.

Redundancy: VPN redundancy keeps users connected and minimizes network outages, given that frequent interruptions disrupt business activities.

Capacity requirements: This is the number of users allowed to use a VPN concentrator simultaneously.


VPN Concentrator Encryption Protocols

VPN concentrators typically come in two security protocols; Secure Socket Layer (SSL) and Internet Protocol Security (IPSEC).

IPSEC is highly recommended because it offers a stronger layer of security compared to SSL.


Pros Of Using IPSEC VPN Concentrators

IPSEC Encryption Is Highly Secure

IPSEC monitors all incoming and outgoing traffic in the network. It operates at the network layer and is transparent to all applications.

Highly Confidential

Data confidentiality is a top priority for most business owners and companies. Given that a lot of information sharing occurs on the network, IPSEC uses public keys to encrypt data and safely transfer it to the intended destinations. The public keys are instrumental in verifying that the data has been received from a legitimate host.

Does Not Depend on Third Party Applications

IPSEC's security is independent of third-party applications because it implements its security at the network layer. As a result, modification is only done to the operating system.


Cons Of Using IPSEC VPN Concentrators

Requires Specialized Skills To Configure

IPSEC VPN concentrators require a qualified technician to install and configure, which is costly and time-consuming.

CPU Overhead

The process of encryption and decryption of data using the IPSEC protocol consumes a lot of CPU resources. This may likely affect network performance depending on the size of the data packets sent and received over a network. 

Unlimited Access

Unlimited access is a major disadvantage because the authorization of a single device to the private network offers similar privileges to other devices. For instance, if you use a device in your home to connect to an IPSEC-based network, any other device in your home can gain access to the network. Therefore, if the device is exposed to malware, it may compromise the IP layer and spread the malware to other computers in the corporate network.

Incompatibility Issues

The IPSEC protocol does not support software that does not meet its standards. Users may also find it hard to switch networks after they register on an IPSEC-based network because it has many firewall restrictions. If you are a freelancer working on various projects that use different VPN concentrators, you may find switching to a different network difficult.


Most standard web browsers have inbuilt SSL functionalities. There are no installations or configurations required with this type of VPN concentrator. SSL users can also manipulate access, especially for web-enabled applications.


Pros Of Using SSL VPN Concentrators

SSL VPN Concentrators offer many benefits to users. Here are some great examples:

Zero Software Requirements

Unlike its counterpart IPSEC, SSL does not require additional software or specialized configuration skills. Users in an SSL-based network can easily access company resources from their web browsers. This helps the organization cut down on extra charges related to purchasing, maintaining, and administering client software.


SSL encryption ensures that only the intended recipients can read and interpret the data received. Given that the data passes through the internet, chances of exposure to third parties are high. For this reason, SSL establishes authenticated and encrypted links to protect data during transfer.


SSL verifies each site visited, assuring all users that the site is reliable and trustworthy. If you notice a lock symbol and at the top of the address bar on the website you visit, just before the Uniform Resource Locator (URL), it means that the site has SSL encryption.

Such measures assure users that they're on a legitimate site and reduce the risk of phishing.

Phishing is when an attacker creates a fraudulent site disguised as a legitimate site to steal user data.


Given that information transmitted through the internet passes via numerous parties, SSL includes an authentication certificate. The authentication certificate only allows users with the correct credentials to access a given set of data.


Cons Of Using SSL VPN Concentrators

Slowed Performance

The process of SSL encryption and decryption is a power-intensive activity that slows down the speed of accessing a website, especially those with high traffic.

Additional costs

Although SSL functionalities are inbuilt in most standard web browsers, obtaining an SSL certificate can be pricey. The SSL certificate expires after a given period and requires regular renewal. If not renewed in time, it can compromise the security of the website.

Web Caching

When users input their details on a browser, a considerable amount of private information may be left behind through web caching.

Web caching is the process of storing frequently requested web objects or web pages to lessen the burden on web servers and improve user's experience.

For instance, if your browser already knows what you are looking for, based on your previous browsing history, it will take a shorter time loading a particular web page from its archives than when searching from scratch.

Therefore, a business or organization will need to invest further in a server that encrypts the data before caching.

VPN Concentrator Alternatives

Based on your organization's needs, you should be aware of other alternatives with similar functionalities as the VPN concentrator. Also, when deploying a VPN concentrator, it is important to differentiate it from regular routers, servers, and firewalls, such as the ones listed below:

VPN Router and VPN Concentrator

The VPN concentrator, as mentioned earlier, extends the capabilities of the VPN router. As a large business or organization, you need to assess your business needs and the magnitude of activities on a day-to-day basis.

Each business has its own unique set of security needs, and this should act as a guide in selecting either a VPN router or concentrator.

Small businesses with a handful of employees are better off with a VPN router to optimize their operations. A VPN router has VPN software installed into it, ethernet ports, and the latest Wi-Fi technologies. You can use a VPN router to share files across the network and remotely access programs and devices.

On the other hand, large businesses with many remote employees should consider investing in VPN concentrators because a VPN router cannot support network connections from geographically separated work sites. A

VPN concentrator can handle the volume of traffic generated by users in different locations. It does this by creating and managing thousands of VPN tunnels simultaneously.

VPN concentrators also offer the option to expand using the Scalable Encryption Processing (SEP) modules if a client wants to increase capacity but still maintain high performance and efficiency.

VPN Concentrator and a Site-to-Site VPN

A Site-to-Site VPN is an established connection involving two or more networks. A good example is a business that has several branches. When a branch office tries to access the head office network, it uses a Site-to-Site VPN connection.

In that case, a VPN concentrator may not be suitable. A VPN concentrator manages VPN communication infrastructure, while a Site-to-Site VPN creates an encrypted link between VPN gateways.

VPN Concentrator and VPN Gateway

A VPN gateway has internet-based capabilities. It is normally a physical device but can be a server, router, or firewall whose primary purpose is to block or route VPN traffic. The gateway can also connect two or more VPNs together.

The main difference between a VPN concentrator and a VPN gateway is that all VPN concentrators qualify as VPN gateways but not all VPN gateways can be classified as VPN concentrators.

VPN Concentrator and VPN Firewall

A VPN firewall is specifically designed to shield a network from third-party interceptors and other malicious users that may exploit a VPN connection. A VPN firewall can be software or hardware installed either at the front or back end of the server. It has filters configured to ensure that only specific data packets that have either been encrypted or decrypted can pass.

A VPN concentrator ensures the security of the data while the firewall filters out the data.

VPN Concentrator and VPN Server

A VPN server acts as a host for all VPN-related services. It houses all hardware and software that enable VPN clients to access a connection.

The server is the first point of connection before any access to the VPN is granted. Without a server, a VPN concentrator would not function.


Examples Of VPNs With Concentrators

Cisco AnyConnect is a great option for large-scale corporations, which includes perpetual renewable security licenses. The service scale caters to up to 100 000 users.

The VPN supports SSL secure connections and other protocols, such as IKEv2. It is highly secure and allows no access to network resources without proper authentication. Cisco AnyConnect VPN also offers iOS and Android support and is compatible with major operating systems.

Nord VPN is one of the most popular VPNs used worldwide and designed to cater to any client regardless of size.

Nord VPN enables the addition of licenses, gateways, and dedicated servers. Clients can benefit from the licenses, especially when creating authentication certificates on their sites.

Perimeter 81 Enterprise VPN has tailored packages that serve several clients. In addition, the packages are customizable to suit the specific security needs of different clients.

Clients receive audit reports that allow them to monitor activities and detect any risks before they escalate.

Perimeter 81 Enterprise VPN has multi-factor authentication enabled to prevent third parties from accessing private credentials that could allow them to bypass some security protocols. There is also dedicated in-app customer support to assist users with all their needs.

FortiClient is one of the most user-friendly VPNs on the market. It does not require sophisticated configuration techniques and is easy to manage.

Large-scale clients can benefit from this VPN as it has an all-in-one package that includes endpoint registrations, scanning of vulnerabilities, and remote deployment, among others.

Pulse Connect Secure provides its users with outstanding service and only requires a web browser for configuration. The platform is built in such a way that it scans all devices to ensure compliance with its security standards.

The VPN is network-sensitive and immediately launches a secure connection whenever it detects network changes. It also has a multi-factor authentication method that provides an extra layer of protection from third-party attacks.


VPN Concentrator Options

When deploying a VPN concentrator, you need to consider the two major modes of transferring encrypted data; transport and tunnel.

Transport mode uses the original IP header and wraps the data to ensure it is encrypted and reaches the remote site.

Tunnel mode is a more advanced model that uses an additional IP header and places it at the front of the data packet to prevent interception.

Mobile networks and Wi-Fi hotspots are commonly known for blocking IPSEc traffic. The security protocol chosen will determine whether the data transmitted will be encrypted.


Frequently Asked Questions About VPN Concentrators

The topic of VPN concentrators is broad. Here is a quick look at some of the most common questions relating to this topic and their answers.

Do VPN Concentrators Affect Performance?

VPN concentrators have hardware designed to reduce CPU load, making them highly efficient and productive. The performance depends on the capacity of the model chosen and the number of tunnels created from a connection.

For instance, if a tunnel is designated to allow a maximum of 100 users but not all users are using the tunnel simultaneously, you can reduce the number of users to preserve bandwidth and enhance performance.

You can also monitor the amount of traffic at a given time, especially during file sharing. The process of file-sharing is power-consuming due to encryption and decryption of data.

Suppose there is a lot of traffic that is likely to affect performance. In that case, you can tweak your infrastructure policies to accommodate your needs by incorporating SEP to expand the VPN concentrator.

Are VPN Concentrators Legal?

Yes. VPN concentrators are entirely legal unless when used to conduct illegal activity.


Where Should I Put a VPN Concentrator?

Usually, you'll find VPN concentrators at the front of the network, under or next to a firewall.


How Much Does a VPN Concentrator Cost?

VPN concentrators vary, depending on various factors such as the size of the client, the packages offered, etc. For the exact price, check the plans offered by some of the VPN providers mentioned above.

Data breaches and cybersecurity issues are common occurrences in the digital world. To avoid such incidents, many clients, specifically large-scale businesses or organizations, opt for VPN concentrators. It is therefore advisable to evaluate the security needs of your organization or business and have a VPN concentrator configured for extra protection.

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