FastView Radware s End-to-End Acceleration Technology Technology Overview Whitepaper
Table of Contents Executive Summary... 3 Performance Matters... 4 The Business Impact of Fast Web Sites... 4 Acceleration Challenges... 4 Quality of Experience Visibility Challenges... 5 Radware s FastView Solution Overview... 5 FastView FE Engines... 6 HTTP Requests Reduction Engine... 6 Dynamic Browser Caching Engine (Browser Caching Optimization)... 7 HTML Content Reduction Engine... 8 HTML Image Manipulation Engine... 8 Compression Engine... 8 FastView Network Optimization Engine... 8 FastView BE Optimization Engines... 9 ADC Server Side Caching Engine... 9 HTTP Multiplexing Engine... 9 SSL Offloading Engine... 9 Application Aware Acceleration with Radware AppShape... 10 Fast View End-to-End QoE Visibility... 10 Summary... 11 Smart Network. Smart Business. 2
Executive Summary Today s Web sites performance is an inherent challenge that must be addressed. Faster performing web sites lead to more page views, longer viewing times, increased traffic, increased activity, more users and more transactions resulting in higher revenues and productivity. Fast Web site ROI is fantastic, both from a business and technology perspective. Past examples show that the faster the Web site the higher the revenue and user satisfaction. From a business viewpoint, Amazon gained a 1% increase in revenue for every 100 mill-second of improvement; Microsoft Bing gained a 5% increase in revenue for every 2 seconds of improvement. From a technology standpoint, the capacity and throughput of the current Web site infrastructure has increased dramatically and you can get much more out of your existing Web infrastructure. On the other hand, slow Web sites lead users to abandon the site and move to competitor s sites. A good acceleration solution utilizes several synergetic acceleration methods that impact different layers and components along the path from the client s browser to the Web site server farm. This requires a comprehensive understanding of the underlying technologies, networks, protocols, browser technology, Web site and applications infrastructure. Generally speaking, WPO (Web performance optimization) which covers the path from the client to the Web server could be divided into three main segments; each one can be optimized and has its own acceleration merits. These segments are: Front-end optimization: optimizes the content in order to reduce the number of requests to the Web server as well as reduce the content itself Network and protocols acceleration: optimization of the network transport protocol medium Back -End optimization: computing resources that offload and optimize the server s resources in order to serve requests immediately without accessing the Web servers as well as to offload and save CPU cycles from Web servers Front End Optimization (FEO) - The client acceleration part, the front end optimization (FEO) is responsible for reducing - and sometimes to completely eliminate - the number of requests sent from the client to the server. Typically when the client s browser fetches a web page, first the HTML page is retrieved and then all the page resources. A separate request is sent per each resource. The trick here is to manipulate the page in such a way that would reduce the number of resource requests, and thus improve the user experience. In one optimization technique, serving requests from the browser s cache implies that no requests are issued to get the resources from the Web server. There are several optimization techniques detailed later in the paper. Network and protocols acceleration - The network and more specifically, the transport protocol (TCP) optimizations include methods to rapidly overcome network congestions and error situations. These methods have high performance improvements in mediums where the RTT (round trip time) is relatively long. An example for such networks could be mobile cellular networks, satellite and radio access networks. Back End optimization - The server side acceleration and optimization part should include server side caching which expedites page retrieval times; connection multiplexing which utilizes existing established TCP connections and thus saves the server from opening new connections each time a client connects to a Web server, and SSL offloading which saves computing cycles from web servers. Smart Network. Smart Business. 3
This paper focuses on the acceleration & optimization methods that are all under the hood of Radware s Fastview technology. Fastview is integrated into Radware s ADC product line in order to significantly improve the overall end-user QoE, optimize the datacenter resources as well as to provide important service visibility tools. FastView advantages: Provides maximal business impact in terms of user satisfaction, conversion rate, customer loyalty and generated revenues Faster response time for any user, any browser on any end-user device starting at the 1st page visit Measureable insights with FastView s End-to-End QoE visibility tool Figure 1 below illustrates the end-to-end acceleration schema and maps Radware s FastView components into the three segments on the path from the client and up to the server. WPO with Radware s FastView Technology Clients End-to-End Acceleration & Visibility Web Servers FE Optimization BE Optimizations Network Optimizations Radware s ADC Figure 1 - Radware s End to End Acceleration Performance Matters The Business Impact of Fast Web Sites There are many examples which show that for every second or even a fraction of a second of speed improvement there is a substantial revenue impact. Shopzilla gained 12% in revenue and 25% increase in page views for decreasing page load time from 6 seconds to 1.2 seconds. According to a study by the Aberdeen Research Group, a one second delay in response time, not only decreased page views by 11% and conversion rate by 7%, it also decreased customer satisfaction by a staggering 16%! Harry Schum, a computer scientist and speed specialist at Microsoft states that Two hundred fifty milliseconds, either slower or faster, is close to the magic number now for competitive advantage on the Web. In addition to the speed factor, when the servers computing resources are optimized and offloaded (e.g., compression offloading, SSL offloading, etc) the website can process more transactions serving more users on the existing Web server resources. Acceleration Challenges Web pages size and complexity grows rapidly, the average number of objects per web page just grows over time. Recent surveys show eighty objects on the average. But end-users satisfaction hasn t changed - they are not tolerant for performance degradation. Providing the user with an excellent quality of experience in order to capture his/her attention and not losing it when he/she browses the website is challenging. In order to answer this challenge, it is important to know what to accelerate and what not to accelerate and assigning the most relevant acceleration & optimization technology accordingly. Price performance is important and you want to put your CPU cycles where you gain the maximum or the most speed improvements. Smart Network. Smart Business. 4
Key challenges that need to be answered are: Radware s End-to-End Acceleration Technology Overview Whitepaper How can you optimize resources to meet end-users SLAs? How to select and optimize the acceleration technologies per business application and network conditions? How can you choose what and when to accelerate in order to gain the highest value from your acceleration technologies? How can you establish a scalable solution that can support hundreds of thousands of transactions per second? How can you reduce network complexity and achieve better manageability of your acceleration technology and your over all application delivery solution? How do you provide the best QoE to the specific user, device and location? The following sections address these challenges in more details and introduce the applicable technologies that are required to build an efficient working acceleration solution. Quality of Experience Visibility Challenges Web environments change rapidly, sometimes several times a day. In such environments any change can impact the application and service level delivered. How do you: Ensure your application performance meet your expectations? See each of your clients transaction quality of experience? Proactively maintain your application performance? These challenges should be answered through visibility tools that can present an end to end, measurable, quality of service. The end-to-end path from clients to Web servers is a combination of several infrastructure technologies, each having its own complications. Each part has its own silo monitoring tools, however, monitoring and visibility into the end-to-end QoS (quality of service) is limited. Visibility parameters such as: which users get good SLA and which are not, QoE per geographical regions, HTML resource performance as seen by real end-users, and more, are required in order to make sure you are providing good service to your web site visitors. Measuring the real end-user experience and being able to break it down by different criteria is crucial and mandatory in today s rapidly changing Web environments. Radware s FastView Solution Overview Radware application delivery solution delivers a future-proof, application-aware approach to deploying and managing applications, guaranteeing their availability, performance, and security while allowing to on demand scale and provide the ability to extract more value from IT investments in the physical and virtual data center. Radware s Fastview is Web Performance Optimization (WPO) technology which delivers a set of advanced acceleration engines, gaining maximum speed utilizing the available resources, all of which are integrated into Radware s ADC product line. These acceleration engines work in concert in order to provide an end-to-end acceleration from clients to servers. Smart Network. Smart Business. 5
Figure 2 below illustrates the acceleration engines: End-to-End QoE Visibility Radware s ADC Clients FastView FE Engines HTTP request reduction Dynamic browser caching Content reduction Image manipulation Compression Network Optimization TCP Optimization FastView BE Engines Caching HTTP Multiplexing SSL offloading Web Servers Figure 2 - Radware s Fastview Acceleration Engines FastView FE Engines FastView front-end optimization engines are responsible for reducing the transferring time of HTML content from Web servers to clients. FastView FEO engine accelerates HTTP traffic through HTTP request reduction and HTML content reduction techniques. HTTP Requests Reduction Engine One method to speed up Web page load times is to aggregate multiple resources into one big resource file and fetch it in one request. This is done through combining and inlining techniques. Combining is putting multiple resources, CSS (cascading style sheets) or JS (javascript) in one file that is served in a single HTTP request, therefore reducing the number of HTTP requests by the number of combined resources minus one. Inlining is the process of adding multiple separate resources and planting them into the HTML page. There is one HTTP request to fetch the new augmented HTML page including the added resources, therefore reducing the number of HTTP requests by the number of inlined resources. The difference between the two is that combining resources enables caching later on at the client s browser cache where inlining doesn t allow it. Typically, small resources are inlined. The HTTP request reduction engine utilizes resource combining and inlining HTML optimization techniques to reduce the number of HTTP requests for HTML CSS and JS resources. Figure 3 shows HTTP requests riding over a single TCP connection to illustrate how this acceleration engine results in reduced number of HTTP requests after applying the combining technique on the HTML page that the web server returns. We see that instead of three separate HTTP requests we have only one request to get the combined resources. Smart Network. Smart Business. 6
HTTP Request HTTP Request HTML page HTML page Request resource 1 Resource 1 Time HTTP Request for combined resources Combined Resource (1+2+3) Request resource 2 Time Resource 2 Request resource 3 Resource 3 Before After Figure 3: Illustration of resource combining (request reduction engine) Dynamic Browser Caching Engine (Browser Caching Optimization) FastView s dynamic browser caching engine optimizes the client s browser cache to cache maximum number of resources at the client side. Many HTML resources can be cached but de-facto they are not. 58% of cacheable content is not flagged properly. Many HTML resources do not have caching attributes like expires or max-age at all. Moreover, even if the resource is in the browser s cache but the browser issues an If-Modified-Since, it requires a new request or even a new TCP connection be opened which could be time consuming especially in mobile environments. Adding caching attributes enables the client s browser to store resources at the client side. The trick is how to do it without serving outdated objects. Dynamic caching has a magic, of the magic is serving as many as possible resources from the browser s cache. This means that if optimized properly most or even all resources are in the browser s cache and minimum number of requests are sent. Even if-modified-since requests are not sent because a max-age attribute with a long expiration time is already added to the object. The content is immediately served from the browser s cache. Client Browser ADC Client HTML page request HTML page request HTML page response Objects from browser s cache New object version Browser Cache Only asks for outdated objects Objects with new suffix version Gets objects 1. Checks if objects are cacheable 2. Add max-age expiration 3. Checks if objects are outdated Web Servers Figure 4 - Dynamic browser caching engine Smart Network. Smart Business. 7
Figure 4 above illustrates the main components of the dynamic browser caching. FastView dynamic browser caching engine knows to differentiate between cacheable objects and non-cacheable objects. For cacheable objects it adds an expiration time accordingly and changes the version suffix once the resource is changed. We see that many requests are being served by the browser s cache without the need to get the resources from the Web servers at all. The dynamic browser caching engine utilizes an object versioning mechanism to avoid serving outdated objects. The browser requests for the HTML page each time the page reloads. HTML pages have no caching attributes and in some cases also have a must-revalidate attribute in the HTTP headers. When the HTML request gets to the ADC it scans the page and checks if any of the objects in the page have changed. If yes, the engine rewrites the HTML page with a new object suffix versions, which causes the browser to get the new objects and cache them again. Now the updated objects are available in the browser s cache for subsequent requests. Optimizing what goes into the browser s cache has a major impact on end-user QoE and FastView s dynamic browser caching engine manages it. HTML Content Reduction Engine The HTML content reduction engine utilizes the minification technique to remove unnecessary characters from HTML resources to reduce its size. All comments and white spaces (space, newline and tab) are removed. This operation results in a reduced size of the downloaded objects. Another technique that is utilized by this acceleration engine is URL trimming. It reduces the HTML size by replacing the link s absolute path with the link s relative path, removing the scheme and host URL parts. For example when you access http://www.site1.com/images/central_wlogo.gif the trimmed URL in the page will be./images/central_wlogo.gif thus saving 21 characters. HTML Image Manipulation Engine The image manipulation engine adds image size attributes where they are not originally presented in the HTML. Many times when downloading a Web page we see that a large image is downloaded and momentarily obscures the display and other resources, and then when the rest of the page is downloaded the browser fits the image in its place. FastView image manipulation engine prevents jumping images and enhances the page draw time. This is important from an end-user QoE point of view. The engine supports major image formats such as GIF, JPEG and PNG which covers 98% of the images on the Web. Compression Engine Compression reduces the amount of data transferred to clients from the point in the network which it is compressed. FastView compression engine reduces the data sent to clients as well as saves CPU cycles from Web servers since the compression is done in one place at the ADC device instead of on the Web servers themselves. Compressed objects are also cached by Fastview BE caching engine (described in section 3.3.1 below), which is another example of how the acceleration engines work in synergy to increase efficiency. The Fastview compression engine supports Gzip encoding format, which is supported by all main browser types. FastView Network Optimization Engine FastView TCP optimization supports several optimization techniques to optimize the transport control protocol congestion avoidance and recovery mechanisms to fit different network environments. Transmission Control Protocol (TCP) uses a network congestion avoidance algorithm that includes various techniques to efficiently transfer data. In general, everything works well as long as no traffic congestion is identified (e.g., no packet drops, relativity short round trip time etc.). On the other hand TCP congestion avoidance Smart Network. Smart Business. 8
algorithms don t provide good performance results in network environments that present dynamic latency and high RTT (Round Trip Time) connections such as mobile, satellite and slow radio access networks. These environments require the integration of additional TCP congestion avoidance and recovery optimization methods which control the data transmission window sizes in a way that allows faster connection recovery. Integration of such algorithms and their proper activation according to the network conditions is crucial in order to achieve best performance. FastView network optimization engine supports TCP congestion control including window size treatment to overcome slow starts at initial connections and when window size drops down (RFC 5681). FastView supports selective ACK options (RFCs 2018, 2883) to efficiently recover packet loss situation without enforcing the endpoint to resend the whole data again but rather to retransmit only the data segments that were actually lost. FastView also supports enhanced loss recovery using limited transmit (RFC 3042) and the New Reno algorithm (RFC 3782) FastView includes an advanced TCP Hybla implementation. This is the latest proven development in the space of congestion avoidance and recovery algorithms which fits very well in networks that are typified by dynamic latency and high RTT connections. This stack implementation uses techniques that know how to recover very smoothly from congestion problems in these dynamic networks conditions. FastView BE Optimization Engines FastView back-end acceleration engines have a twofold objective. The first is to offload CPU cycles from Web servers and do it from one control point at the ADC device. This result is less deployed servers which reduces CAPEX and OPEX and increase the data center utilization level. The second objective is to accelerate the service by directly serving Web pages from the ADC device. ADC Server Side Caching Engine ADC server side caching saves the time to get HTML resources from Web servers. Instead HTML resources are cached at the ADC and served immediately by the ADC. This caching engine automatically identifies which resource was changed, its level of usage (e.g., visitors hit ratio, last access time etc) and maintain an efficient cached resource list accordingly. Server side caching enhances QoE by faster load times of 1st viewed objects, meaning objects that are first time fetched by the client and not cached yet at the client s browser. The combination of both Fastview s server caching and FE dynamic browser caching engines complement each other, allowing both 1st views of objects as well as repeated views of objects to be accelerated. HTTP Multiplexing Engine FastView HTTP multiplexing keeps established TCP connections in front of the web servers and reuses them instead of opening new ones per each new client connection request. This engine saves Web server resources as well as reduces the initial TCP connection setup which is time consuming. Fastview HTTP multiplexing engine dramatically saves and optimizes Web server resources in a few scenarios including web flash crowds that overload the Web server resources due to unexpected peaks of new client connection requests toward the Web server. SSL Offloading Engine FastView SSL offloading terminates SSL connections at the ADC, saving CPU cycles from Web servers. SSL offloading is done in proprietary hardware that is designed to efficiently terminate SSL with 1024 as well as 2048 Smart Network. Smart Business. 9
key size in mutli-gig network environments and can scale on demand. Moreover, Fastview SSL engine does the SSL offloading in one controlled location (Radware s ADC) in front of all Web servers. Doing it from one control point provides better manageability including centrally managed SSL software patches, logging and compliance. Additionally, SSL offloading is needed to execute acceleration techniques like the ones described above. The ADC must see the content, otherwise it is encrypted and cannot be manipulated. Application Aware Acceleration with Radware AppShape Efficient acceleration of different business applications (e.g., Microsoft share point, Oracle Apps, public ecom App or CMS Content Management Systems) requires different acceleration attributes. Radware s AppShape enables a complete application centric management approach. It enables you to manage application delivery optimizations per application regardless of the device or computing resources it uses. AppShape enables you to pre-configure optimization templates per application. Each application has its own attributes that best fits its performance. In order to simplify and optimize the configuration of Fastview acceleration engines, Radware AppShape enables you to assign a pre-defined package of acceleration techniques, each one with the set of attributes that will best serve the application which is subject to acceleration. Appshape enables the customization of acceleration policies to support specific application flows. AppShape allows automatic shaping of Fastview per each accelerated application, make it app aware, and thus provides the maximal acceleration value. For example, if you have SharePoint servers as well as a CMS system, you should be able to apply simultaneously acceleration attributes to all SharePoint servers in one server farm and different acceleration attributes to CMS servers in another server farm. This reduces configuration time, simplifies deployment and eases management. Fast View End-to-End QoE Visibility Measuring the real end-user experience and being able to break it down by different criteria is crucial and in today s Web environments is often mandatory. Radware s End-to-End QoE visibility module answers the challenges of measuring real end-user response times, providing visibility into end-user experience. To measure correctly real end-users QoE and response times, one needs to monitor the end-user activity from the end users point of view without impacting his activity. FastView QoE visibility module utilizes sophisticated techniques that plant a java script transparently in Web pages. The Java script collects key statistics from the end user browser and reports it back. It provides response times and key statistics by the following categories: Location Shows response time breakdown by location. This view allows you to identify which locations breach SLA and help to understand whether the problem is location specific or happens at all locations. Application Shows response time breakdown by application. This view helps to determine whether the problem is specific to one application or to all Web applications. Transaction - Shows response time breakdown by transaction and URL. This view identifies which transactions breach SLA and helps to understand whether the problem is specific to one transaction or URL or if it impacts all URLs. Smart Network. Smart Business. 10
FastView QoE Visibility module allows IT managers to see their real end-users experience, capture end-user real time error statistics and to breakdown the end-to-end client to Web server path and visualize the contribution of each component to user response times. This visualization capability allows optimizing the FastView s acceleration engines and utilizing them better where they are really needed. With Fastview QoE visibility module, analyzing performance related problems and the challenge of choosing the acceleration engine that will provide the highest value becomes a simple task. This end-to-end application performance monitoring solution captures actual user QoE, based on actual application transaction latency and real time errors providing: The visibility required to continuously ensure that the web applications meet the business SLA An efficient troubleshooting tool for fast and accurate detection of performance issues, all in real time. Simplified deployment, with no dedicated scripts per web application, lowering costs Summary This paper presented the importance and business impact of Web application acceleration, the various technological challenges, and the various applicable techniques that form a true end-to-end acceleration technology. Radware s FastView technology introduced in this paper provides IT managers with a complete set of acceleration techniques that form the required end- to- end acceleration for Web sites. It answers the most important performance, user QoE and user SLA challenges that on-line businesses struggle with including: How can you optimize resources to meet end-users SLA How can you establish a scalable solution that can support hundreds of thousands of transactions per second? How can you choose what and when to accelerate in order to gain the highest value from your acceleration technologies? How can you reduce network complexity and achieve better manageability of your acceleration technology and your over all application delivery solution? Radware s ADC product line together with FastView technology presents an acceleration solution that works for all users, browsers and websites and answers all the aforementioned challenges. FastView technology delivers: Maximal business impact - Increased page views - Improved customer satisfaction - Business applications that meet business expectations Value for all users supporting all browsers and end-user devices for 1st and repeated page visits Measurable insights with FastView s End-to-End QoE visibility 2012 Radware, Ltd. All Rights Reserved. Radware and all other Radware product and service names are registered trademarks of Radware in the U.S. and other countries. All other trademarks and names are the property of their respective owners. Smart Network. Smart Business. 11 PRD-FastView-Tech-WP-02-2012/07-US