As many data center operators know, it is difficult to control all aspects of the network between the application server and the end customer, which poses significant challenges for application performance. Fortunately, many tools and features are available to help accelerate application content to ensure optimal delivery and offload backend server infrastructure.
To accelerate traffic and optimize infrastructure, various techniques can be employed on the Thunder and AX Series Application Delivery Controllers (ADCs):
Network level TCP optimization to reduce unnecessary TCP connections via connection reuse, dynamic window sizing, or TCP multiplexing
Connection reuse reduces the overhead associated with setting up TCP connections by establishing persistent TCP connections with backend servers and then reusing those connections for future TCP requests. This feature offers a significant benefit as it reuses existing TCP connections rather than opening new connections for every single client. The connection reuse feature terminates all client connections on the ADC, maintains persistent connections to servers, and sends all client requests on these persistent connections.
Content caching (static or dynamic RAM caching) to accelerate the user experience and decrease Web server requests
Compression to reduce transmitted data payloads
HTTP Compression is a bandwidth-optimization feature. It provides compression for HTTP/HTTPS objects from web servers. This causes responses to use less bandwidth, which results in faster downloads for HTTP/HTTPS objects. Examples of objects that can be compressed are text-based formats such as CCS, HTML, or JS, or application formats such as .ppt, .doc, .xls or .pdf.
Many of today’s enterprise deployments require that data must be encrypted using SSL before packets are transmitted over a network. The SSL offload feature reduces server overhead by offloading the decryption of encrypted packets from clients. The SSL processes can create a significant load and limit the overall capacity of a backend server if the SSL processing is directly performed by the web servers, providing CPU relief.
Traditional load balancers lack the granularity to analyze and manipulate traffic at the application layer, for example HTTP at Layer 7. Without programmatic control of application traffic, you cannot address important use cases like transforming web content, bolstering security, or improving users' web experience.
aFleX Custom Scripting Language
A10 places an extensive set of controls at your' fingertips with A10 Thunder and AX Series' intuitive web user interface and industry-standard command line interface, frequently network operators need more; they need to examine, update, duplicate, or drop traffic and they require full control over the data stream.
aFleX, an advanced scripting language for A10 Thunder and AX Series, provides the flexibility and power that network operators need to fully control their application traffic. aFleX is built on Tcl (Tool Command Language), an easy-to-learn scripting language; it also offers a set of extensions specifically designed for A10 products.
With aFleX, you can create policies to inspect content--including request headers and payload —and perform any number of actions, such as blocking traffic, redirecting traffic, or modifying content.
aFleX offers granular control over application traffic, providing customers many benefits; some examples include:
Optimized high availability:
With aFleX, you can redirect end users to backup data centers if primary data centers are unavailable. Customers can also redirect users to custom error pages if the server is unresponsive.
Using simple aFleX rules, you can redirect users from HTTP to HTTPS (SSL) applications, rewrite URLs, and forward specific clients to specific servers based on client attributes, such as browser accept-language.
More stringent security:
aFleX scripts can be defined to cloak web server settings or to block specific clients based on client behavior or attributes.
By updating cache-control headers, aFleX can improve end users' web experience by caching static content in users' browsers