A faster loading web site or intranet provides users with a more satisfying experience because there is a shorter wait for web pages to render and be usable. Statistically, it has been observed that if a webpage takes longer than 7 seconds to load, users will abandon the action. For most web pages, less than 20% of the end user response time is spent by the web servers producing the HTML web page document, while 80% of the end user response time is spent transferring the document from the web server to the browser. This means with an average web page load time of seven seconds, only about one second is spent in “server processing”, while six seconds are spent in “browser processing” – the browser downloading all the page resources and rendering the page. Reducing web page load time is vital to improving user experience. Riverbed’s wide area network (WAN) optimization solution has traditionally employed a symmetrical deployment of Steelhead appliances to improve end user performance by application and transport streamlining techniques, along with data deduplication to conserve network bandwidth. While these techniques are better equipped to work on moving data across the network, there are other techniques that work better by optimizing the content on the server itself. Web content optimization (WCO) is the technique used to streamline web page content by optimizing the HTML content on a webpage. Stingray Aptimizer uses WCO techniques like pre-fetching HTML objects, caching and compression to improve page load times. While WAN optimization and web content optimization ultimately have the same end goal of improving user performance, the techniques employed serve different use cases. In the rest of this paper, we will examine how each of these two techniques optimizes delivery of web content both separately and in a complementary fashion.
Stingray Aptimizer is a Web Performance Optimization (WPO) tool that performs just-in-time optimizations to web applications. This results in web pages loading up to 4x faster while using 30% less bandwidth. Being just-in-time means optimizations are performed on the fly with no code changes needed. Stingray Aptimizer optimizations are split into four basic categories:
Combining Files: Merging multiple files into a single larger file to reduce round trips
Data Reduction: Reducing the bandwidth used by compressing and removing unnecessary data
Caching: Reducing the amount of traffic by optimizing the usage of both the browser cache and the intermediary cache network that lies between the server and the end user
Dynamic layout: Dynamically adjusting the layout of pages to ensure they load as efficiently as possible.
The Stingray Aptimizer Technical Overview provides a detailed technical overview of the optimizations performed in each category.
Aptimizer Express dynamically optimizes webpages in the background and provides customers with webpages that load significantly faster while reducing data traffic on their network. WCO is the industry term used to describe transforming webpage content on-the-fly into the most compact form, without developers having to manually optimize the behavior and performance of each web page. High-traffic, public-facing websites, corporate websites, e-commerce sites, business productivity tools, and SharePoint applications are transformed for faster delivery, lower-bandwidth requirements, and better user experience.
Aptimizer Express is an add-on module for Stingray Traffic Manager that provides a set of robust optimizations to accelerate the delivery of most web pages, no configuration or tuning is required. This advanced WCO capability with Stingray Aptimizer Express is available as a licensed add-on module for Stingray Traffic Manager 9.5.
Stingray Aptimizer Enterprise is the full featured version of Aptimizer that is available as pure software for web server installs, as an add-on module for Stingray Traffic Manager, or as a pre-packaged software appliance for virtual and cloud environments.
Here is what Aptimizer Express does to your website to speed up pageloads.
Inline CSS Background Images
Aptimizer Express includes image data in CSS files by encoding the data as Base64 and using a data URI to insert it in the style sheet. Including the image data in the style sheet eliminates a request/response roundtrip between the browser and server, which ultimately speeds up page load times. Background image inlining is good for websites with a lot of small, static images.
Many websites download images that are higher quality than actually required. Aptimizer Express resamples JPEG images, which reduces the file size without any perceivable visual difference when compared to the original image. This feature is particularly valuable to websites that use a large number of JPEG images.
Remove Redundant Image Information
Aptimizer Express automatically strips redundant metadata information from images resulting in smaller file sizes and reduced bandwidth usage. This data can include exif, date/time, and descriptive information. This feature is particularly valuable to websites with a larger number of images.
Version and Cache Resources
When a user visits a website resources (images, web fonts, etc.) are downloaded and stored in a cache on the user’s computer. On subsequent page loads many websites will unnecessarily re-download these resources even though they haven’t changed. Resource versioning eliminates these unnecessary requests by intelligently naming resources so that downloads only occur when the resource is modified. Aptimizer Express applies versioning only to resources referenced via CSS, so will provide the most benefit to sites that utilize CSS heavily to load images and web font files.
Caching of Non-Versioned Resources
For any resources that are not versioned, Aptimizer Express will modify the Cache-Expiry header so the resource persists in the client cache and isn’t downloaded every time the page is requested. This reduces the number of round trips on page loads and subsequently reduces page load times and bandwidth cost.
ETags provide a way to determine whether the resource stored in a browser’s cache matches the one on the server. The first time a resource is downloaded, Aptimizer Express attaches a unique ETag header. On subsequent requests for the resource the browser sends the ETag back to the server, which the server checks and then only sends back the resource if it has been modified (resulting in a new ETag). If the resource has not been modified, Aptimizer Express responds with a 304 ‘Not Modified’ response (containing no data). ETags work together with versioning and caching on the browser to eliminate unnecessary downloads and will help significantly improve page load time and reduce bandwidth usage. ETags will provide benefit for any website.
Aptimizer Express parses CSS documents and detects when additional style sheets are referenced via CSS @import tag. Aptimizer Express will insert, or ‘flatten’, the contents of any referenced (child) style sheets into the original (parent), eliminating the need for a separate roundtrip to download children style sheets from the server. This feature reduces page load times, especially for websites with a high number of CSS @import references.
Compressing resources is an easy to way to reduce the size of data being transferred from server to client, reducing bandwidth usage, and speeding up page load times. Once Aptimizer Express has applied other optimization techniques it applies deflate compression to resources before serving them to the client’s browser. Compression provides benefit to a wide range of sites.
Pulse Web Accelerator (Stingray Aptimizer) for SharePoint speeds up any SharePoint website or intranet, reducing page load times up to 33%-75% using a patent pending process for reducing round trips a browser makes to the server to load the page, delivering speed increases with a simple software installation on the web server. No extra hardware, no website or browser changes, and no additional costs
Stingray Aptimizer for SharePoint speeds up any public website or intranet, reducing page load times up to 33%-75% using a patent pending process for reducing round trips a browser makes to the server to load the page, delivering speed increases with a simple software installation on the web server. No extra hardware, no website or browser changes, and no additional costs.
Stingray Redefines Application Performance for ADCs Focus on website content optimization (WCO) to drive e-commerce revenue, user engagement, and employee productivity The only complete full-featured virtual ADC with integrated WCO, supported on the widest range of virtual and cloud platforms. Stingray Aptimizer is also now available as a stand-alone web content optimization tool to accelerate existing ADC environments FREE Stingray Developer License now makes it even easier for application and security professionals to access capabilities