NetScaler vs F5: Comparison between Citrix ADC (Formerly NetScaler) and F5 BIG-IP

An application delivery controller (ADC) optimizes application performance using load balancing and a host of other methods. It’s also used in application security, covering web application firewall, proxy/reverse proxy and intrusion detection capabilities. Citrix ADC and F5 BIG-IP are two of the more popular ADCs in the market. Both are available as hardware and software, on-premises or on the cloud.

What Is an Application Delivery Controller?

An influx of incoming user requests can potentially bring down your applications. To prevent this from happening, you can use an ADC to let your applications respond to requests in the best way possible.

With an ADC, incoming traffic can be directed to application servers based on specific algorithms, with the simplest being the round-robin, where requests are sent sequentially to available servers. More complex algorithms can include servicing requests based on factors such as load capacity, type of content requested, and client location.

While used traditionally in load balancing, ADCs have since evolved into a more complete tool with a myriad of features and functions, including:

SSL offloading: Instead of backend servers, ADCs can be used to decrypt and encrypt Secure Sockets Layer (SSL) requests. This frees up application servers for other tasks.
Caching: Local content can be stored on ADCs, fast-tracking delivery and reducing server loads.
File compression: ADCs can be used to compress large images, music and videos, increasing your network capacity and allowing for speedy delivery over the network.

In terms of security, ADCs provide web application firewalls that secure applications from external threats such as distributed denial-of-service (DDOS) attacks.

Although once purely hardware devices used in datacenters, the contemporary software-based ADCs are ideal for use in cloud services. While internal IT and network teams still run most ADCs, DevOps engineers may be given more responsibility in managing them in the future, since many of the applications running on ADCs already require DevOps expertise.

What Are Some F5 BIG-IP Features?

F5 BIG-IP is a suite of products that includes a hardware and software ADC and a range of security solutions. It runs on the proprietary Traffic Operating Management System, which is designed specifically to manage network and application traffic.

Running on top of the F5 BIG-IP’s custom OS are the following ADC modules:

BIG-IP Local Traffic Manager (LTM): Provides load balancing and security features for a single site.
BIG-IP DNS (formerly Global Traffic Manager): Provides load balancing and security features for multiple sites.

The F5 BIG-IP’s other modules include:

BIG-IP Access Policy Manager (APM): Provides federation and single sign-on (SSO), among other security features.
Secure web gateway services (SWG): Used in conjunction with APM for access policy control on the internet.
BIG-IP Application Security Manager (ASM): This is the suite’s web application firewall, which also features granular application protection.
BIG-IP Advanced Firewall Manager (AFM): Optimizes your network when using traditional firewalls. It can be paired with ASM for a full-featured security solution.

Aside from the software ADC and other modules, BIG-IP also offers custom hardware that can be deployed on-premises or on the cloud, or a combination of both.

What Does Citrix ADC (Formerly NetScaler) Offer?

Citrix replaced its Citrix NetScaler load balancer with Citrix ADC, adding other features that made it far more capable in the process, including availability, acceleration, security, front-end optimization, TCP protocol optimization, management services and gateway services.

Citrix ADC is built on a single codebase and can be managed centrally via Citrix Application Delivery Management (ADM), allowing IT teams to monitor its health and performance. It uses access control lists and IP reputation filtering for network security, can mitigate DDOS attacks via SYN cookies and HTTP denial-of-service (DoS) protection, among other measures, and performs SSL encryption and decryption. Citrix ADC also comes with an application firewall and has integrated bot-management features.

Other Citrix ADC features include caching, HTTP and other forms of compression, image optimization for faster download times, and prebuilt Transmission Control Protocol (TCP) profiles to ensure optimal TCP communications. It is also capable of intelligent health monitoring, allowing it to send requests to healthy application servers and ignore nonresponsive ones.

Citrix ADC is available on virtual platforms as a virtual appliance and can be installed on both private and public clouds. It supports Amazon Web Services (AWS), Microsoft Azure and Google Cloud Platform, and can also be packaged and run as a container.

Aside from virtual platforms, Citrix ADC can be run as a physical appliance in on-premises datacenters.

How Do Citrix ADC (Formerly NetScaler ADC) and F5 BIG-IP Compare?

While Citrix ADC and F5 BIG-IP offer almost the same features, how do they compare with each other? Here are some comparison points:

Cost: Citrix ADC has free and paid options, while F5 BIG-IP is more expensive.
Ease of consolidation: The Citrix Networking SDX allows organizations to consolidate their ADCs with relative ease. While F5 BIG-IP offers the same capability via virtual Cluster Multi-Processing (vCMP), the consolidation process is far more complicated.
Scalability: Citrix ADC can cluster up to 32 physical or virtual appliances together using a single IP address. The aforementioned F5 vCMP can do so using only four to eight blades, far lower than what Citrix offers.
vMarket share: Despite its seeming advantages, Citrix ADC remains less popular, lagging behind F5 BIG-IP, which remains the market leader.

Parallels RAS Provides Load Balancing Out of the Box

Parallels® Remote Application Server (RAS) offers full support for your load balancing requirements. Using Parallels RAS, you can load balance your entire IT infrastructure without configuring complex networks or acquiring expensive hardware. You can also enhance your original load balancing investments for use in wide area network (WAN) scenarios.

Parallels RAS supports simple round-robin load balancing, which is a rotational-based mechanism that load balances the connections, with the first request granting access to the first available server address, the second to the second server address, and so on.

Parallels RAS also supports resource-based load balancing, which dynamically distributes the traffic between servers based on counters, such as the number of existing user sessions, memory and CPU utilization. It also reconnects disconnected servers automatically, so users don’t lose any work or data.

Parallels RAS allows multiple High Availability Load Balancers (HALB) to load balance traffic to different Secure Client Gateways in the same Parallels RAS site. Parallels RAS also optimizes application delivery when using third-party load balancers such as Citrix ADC.

Check out how you can use Parallels RAS for your load balancing requirements by downloading the trial.