13865 Sunrise Valley Drive Herndon VA 20171

Dynamic Performance Acceleration:

Reducing the browser bottleneck

2 | Page

Table of Contents What is Dynamic Performance Acceleration? ...................................................................................... 3 

Historical delivery challenges ............................................................................................................... 3 

Network reach ......................................................................................................................... 3 

Datacenter consolidation ........................................................................................................ 3 

Dynamic Websites ................................................................................................................... 4 

Browser communication is the new bottleneck ............................................................... 4 

Measuring  Time‐to‐Action ................................................................................................................... 5 

Different  from Traditional CDN Services ............................................................................................. 5 

Other Web Page Optimization  Services .............................................................................................. 6 

Dynamic Performance  Acceleration  Technology ................................................................................ 7 

The XO Difference ............................................................................................................................... 8 

Key Technology Features ........................................................................................................................ 8 

Safe script postponing ............................................................................................................ 8 

Viewport  prioritization............................................................................................................ 8 

Intelligent  image  combining ................................................................................................... 8 

lnline  frame  rendering  optimizations .................................................................................... 9 

Javascript  inlining .................................................................................................................... 9 

Recursive  cascading  style sheet inlining ................................................................................ 9 

Browser  connection  limit management ................................................................................ 9 

Compression ............................................................................................................................ 9 

Early  resource  loading ............................................................................................................ 9 

Text replacement/insertion .................................................................................................... 9 

XO  CONTROL ...................................................................................................................................... 10 

Summary ............................................................................................................................................ 10 

3 | Page

What is Dynamic Performance Acceleration?

The XO Dynamic Performance Acceleration solution is designed to optimize a customer's web

pages to enable faster Time-to-Action. Time-to-Action is the amount of time that elapses between

when a page begins to load and the time that an end user can interact with that web page. Dynamic

Performance Acceleration transparently optimizes the customer's web sites by rewriting elements of

the HTML page in such a way that it accelerates the page rendering process.

Dynamic Performance Acceleration is part of the Acceleration family of services specifically

designed to support dynamic web site acceleration:

• Basic Acceleration: Accelerate dynamic web sites through the use of a global caching and network

optimization to expedite the delivery of non-cacheable content.

• Premium Acceleration: A service offering that combines the benefits of the global

caching platform, network optimizations, and Dynamic Performance Acceleration

Technology targeted at B2C-based (business-to-consumer) applications.

• Mobile Acceleration: A service offering that takes advantage of Dynamic Performance

Acceleration Technology with special optimizations to support smart phone delivery for Apple

iPhone, iPad and Android-based handsets.

Application Acceleration can be utilized as a standalone service, in conjunction with dynamic

site acceleration, or in conjunction with third-party dynamic site acceleration solutions.

Historical delivery challenges

Network reach

Where is the delivery pain point? If we were to roll the Internet clock back ten years ago, in order to

deliver content to end users in an expeditious manner, one would have to have network presence

with over 8,000 different network providers to capture over 80% of the end user eyeball traffic. This

necessitated having multiple connections and lots of deployments in order to ensure end user

performance.

Fast forward to today. Network carrier and ISP consolidation has transformed the network landscape

and is impacting the need for large diverse network footprints. 80% of the world’s eyeball traffic can

now be reached with less than 1,000 network providers. The Internet is becoming a smaller place.

This phenomenon of network consolidation still does not mitigate the need for some form of network

acceleration. However, the major pain point in delivery has shifted given the improved speeds along

the Internet, network backbones and inter-carrier peering.

Datacenter consolidation

Underlying this trend towards network consolidation is the trend towards datacenter consolidation.

This gave rise to the WAN Optimization Controller (WOC) market and its service-based cousin that is

4 | Page

sometimes referred to as Dynamic Site Acceleration (DSA) in an attempt to compensate for the reduced

geographic datacenter footprint. As customers look to support fewer, larger datacenter deployments, it

has a side effect of losing geographic presence. WOC and DSA capabilities help to fill that void by

providing end users with performance that can be comparable to having a local datacenter without the

expense and operational challenges that come with maintaining multiple physical datacenter facilities

and systems. However, in most domestic markets, the network effect is not that strong.

In domestic markets, things like presentation layer optimizations such as GZIP compression play a

larger role in improving dynamic content performance; however, with trans-Atlantic/trans-Pacific long-

haul requests, the network effect can be more pronounced. As customers continue to consolidate and

virtualize their infrastructure, it gives rise to the need for some form of presentation layer acceleration.

Dynamic Websites

The corporate industry trend is to webify traditional back office systems. Part of this desire is to use

cheaper local Internet connections rather than more expensive point-to-point connections. By

decommissioning dedicated branch-to-branch and branch-to-headquarters connectivity and migrating to

HTTP-based applications, versus fat-client server-based applications, companies have more flexibility

with rolling out new features without having to force new end user downloads, offering improved security

through centralized application management, as well as faster time to market. As these dynamic,

mission-critical applications move to the Internet, the user base becomes more sensitive to performance

lag as they use the Internet for their communications backbone. This paradigm is forcing businesses to

address the performance lag for their highly dynamic HTTP-based applications.

With the rise of online commerce as a viable revenue channel to corporations, B2C web sites have

become a more important component in driving top-line revenue growth in corporate boardrooms across

the globe. Hence, more attention and money is being thrown at the web channel in order to drive more

sales and adoption. Along with this trend, B2C websites have become more dynamic, incorporating both

personalized and customized information about the end user in an attempt to provide a more engaging

brand experience, helping to retain customers and drive online adoption. As Internet commerce and

portals have started to come of age, the infrastructure required to support these dynamic applications

have become more complex and expensive to manage. Along with the data center consolidation trend

previously mentioned, complex database-driven websites can greatly benefit from data center

consolidation with less infrastructure to maintain globally. With consolidation, databases don't need to be

synchronized across vast distances, mitigating concurrency issues, as well as simplifying disaster

recovery planning. The other side of the coin is that having centralized applications running over the

Internet creates end user performance issues. Having some sort of web acceleration technology has

been a useful tool in overcoming some of the application performance challenges as a result of the

increased use of dynamic content.

Browser communication is the new bottleneck

The end user web browser is based on the HTTP protocol which is over twenty years old.

Advancements have been made in the browser engine's rendering capability; however, not much

has changed to alter the underlying HTTP protocol to improve end users Time-to-Action. Content

Delivery Networks using DSA or WOC devices can only address so much through network

acceleration and dropping off the content at the closest edge cache server point to an end user. The

end user's browser still has to render the page. Most HTML web pages are comprised of over eighty

objects and five different domain names: images, cascading style sheets, javascripts, third-party

5 | Page

ads, tracking beacons, etc. Most browsers fetch objects in some synchronous fashion with no

priority as to which objects it should fetch to render the page. This leads to an interesting side effect

that impacts the Time-to-Action. When a browser receives a javascript element, the browser pauses

content retrieval while the browser engine interprets the javascript to determine what to do next.

Delivering the objects from an edge server cache does not change this browser-based behavior,

which impacts the last byte download time and the Time-to-Action. The browser cannot render the

page faster even if the objects get there faster – unless there is help. This is where Web Page

Optimization (WPO) capabilities come into play.

Measuring Time-to-Action

Typical web performance benchmarking services like Keynote and Gomez are often used to evaluate

the end user experience. These synthetic tests are often performed from network backbones and

download the content, measuring the DNS lookup time, first byte download, payload download time,

etc. in an effort to ascertain how long it takes to download the objects on a web page. Do end users

really download content at backbone network speeds? Of course not, but as an industry we have come

to accept these tests as a barometer to benchmark performance.

In reality, these tests are measuring how long it takes to last byte download regardless of what actually is

needed for the end user to interact with the page. Web Page Optimization (WPO) is different. It is about

measuring Time-to-Action – how soon can an end user interact with the web page and what elements

comprise the visible field of view? How long it takes to download non-visible elements is largely irrelevant

to the end user experience. Benchmarking browser render time is more impactful to determine the end

user experience.

Different from Traditional CDN Services

Content Delivery Networks (CDNs) can play a vital role in improving the end user experience. They

typically are caching/off-loading common reference objects on the edge caches, while they route

optimize non-cacheable requests back to the origin. This does help improve the end user experience:

but its impact is somewhat muted with respect to the Time-to-Action for an end user. Most WOC/DSA-

type services optimize the network layer transport and attempt to offload some of the common objects

on a page, but they don't do anything to help the browser more effectively render the HTML for the end

user.

In regional delivery markets where content is largely localized, WPO can be a more effective technology

solution for customers as the regional network effect that traditional WOC/DSA services are designed to

address are not really the main pain points in delivery time. WPO addresses the end user experience by

reducing the number of round trips an end user needs to make in order to render the page. Fewer round

trips equates to better performance.

In certain situations, the optimal setting may be using a combination of traditional WOC/CDN-based

content acceleration solutions in conjunction with some form of WPO. WPO reduces the connection and

improves the last mile interaction; while the network optimizations and caching components can be used

to effectively limit the interaction with the customer's origin web infrastructure and expedite non-cachable

content back to the customer's datacenter for long-haul connections.

6 | Page

Other Web Page Optimization Services

There are many different flavors of Web Page Optimization (WPO) in the market today ranging from

server plug-ins to hardware appliances deployed at a datacenter. Below are some areas of interest that

customers need to consider when choosing a WPO vendor:

• Scalability: How does the solution scale for seasonal or unplanned load? Do you need to

deploy more dedicated appliances? If your page volume goes beyond a certain level, do you

need to spend more CapEx?

• Resource Utilization: HTML page transformation can be expensive in terms of memory and CPU

utilization. If you are using a web server plug-in, what effect does that have on your web server's

effectiveness?

• WPO Capabilities: What types of optimizations can the WPO platform offer? Do you need to pre-

process anything?

• Dynamic Content: Some WPO services are designed to optimize over time. The more they see

patterns emerge, the more they optimize the web page; however, many web sites today are

dynamic and constantly changing. When a web page is always changing, WPO technology that

relies on pattern matching never sees the same thing twice, so it is never able to achieve its

optimal state.

• One-size-fits-all approach: All browser technology is not the same. What works well for Internet

Explorer does not necessarily work well for Firefox or Chrome. Some WPO tools only focus on

one type of optimization and do not customize the experience based on the browser type.

• Availability: How does the WPO platform ensure service availability? Do you need to

deploy multiple machines in order to ensure uptime?

• Mobile Acceleration: Does the WPO vendor do anything to help support mobile delivery? Hyper

growth in the smart phone category continues to outpace new desktop PCs sales. WPO vendor

support varies based on capability and efficacy.

• Secure Delivery: Secure Socket Layer (SSL) delivery is an important part of any web site

performing B2B or B2C transactions; however, some WPO vendors do not support delivery of

Web pages over SSL. What good is having a WPO service that can't address your secure

delivery needs?

• Development Resources: Implementing best practices for WPO is something that can be done

with careful HTML programming effort, know-how, and time; however, optimizing page delivery

across a wide range of end user browser environments for an ever-changing website is

something that most customers would rather avoid as it is resource and time-consuming. Using

some sort of WPO capability to automatically leverage WPO best practices is often a better use

of time and money.

7 | Page

Dynamic Performance Acceleration Technology

Application Acceleration incorporates Website Performance Optimization (WPO) functionality

through a series of technologies, blending both the art and the science of WPO in a seamless

service offering. XO encapsulates these techniques under the moniker of Dynamic Performance

Acceleration. Dynamic Performance Acceleration (DPA) is specifically designed to optimize dynamic

web pages without impairing the user experience or requiring any end user browser plug-ins.

Dynamic Performance Acceleration impacts the Time-to-Action. The diagram below illustrates this

concept. In a normal end user browser to web server exchange, requests are made in a serial fashion –

one after another until the page is loaded. With Dynamic Performance Acceleration, objects are

prioritized so that the visible objects are requested first, while hidden objects are downloaded after the

end user's browser viewport, aka above the fold, has been rendered. This content transformation takes

place transparently without content owners having to manipulate their HTML code. The result? The end

user can see and interact with a web page much more quickly. In the illustration below, the web page

loaded in 6.1 seconds without Dynamic Performance Acceleration (DPA). However, with XO DPA, the

same page loads in 3.7 seconds. An important distinction because every second counts when a user is

waiting on your site. Each second the user is kept waiting increases the likelihood that the user will

abandon your page without interacting.

The XO Difference Application Acceleration is different from other WPO solutions both architecturally and

technologically. Like other XO Cloud delivery services, Application Acceleration is sold as

a software-as-a-service model so there is no hardware to deploy, no server plug-ins that

need to be tied into a Web server and best of all, no CapEx. XO integrates into the

delivery path as a proxy server whereby traffic is directed to the Application Acceleration

platform by way of a canonical name (CNAME) via a DNS directive. As a result,

Application Acceleration provides customers with a global platform, with no single point

of failure, enabling elastic functionality for on-demand scalability. As your website

grows, the Application Acceleration platform just seamlessly expands to fit your needs;

furthermore, because Application Acceleration is executed as a service, customers get

to take advantage of new capabilities as the market evolves – future proofing your web

site to always take advantage of the latest WPO advancements. No software upgrades

to plan or purchase, thus reducing maintenance costs, management overhead and

headaches.

More importantly, Application Acceleration has been optimized to perform dynamic WPO

optimizations to provide the industry's fastest Time-to-Action. This manifests itself in higher

end user conversions on your site, improved end user experiences, and reduced site

abandonment – leading to increased site stickiness and website adoption.

Key Technology Features

Safe script postponing

Safe script postponing controls the execution of things, like javascript. Safe script

postponing seamlessly delays scripts with no adverse effect on HTML page rendering.

Web pages retain their original look and behavior.

Viewport prioritization

Viewport prioritization conditions the browser to request certain objects before others.

This is done in an effort to improve the Time-to-Action for the above-the-fold end user

experience. This technology can also be used to promote certain objects so they render

first, e.g. third-party advertisement scripts.

Intelligent image combining

Dynamic Performance Acceleration has the ability to combine images into larger payload

downloads that some people refer to as image “spriting”. Intelligent image combining is an

example of the art and science of WPO at work. If one were to try to optimize the last byte

download experience, one could combine all the objects on a page into a single large

object for download and let the end user's browser decompose the image sprite;

however, combining all the images into a single resource has an adverse effect on Time-

to-Action as inevitably objects that are below the fold and not necessary for the viewport

are being downloaded. The magic of the XO Dynamic Performance Acceleration

9 | Page

technology is to know what elements are required to render the above-the-fold

experience and combine only those image resources necessary to render the viewport –

dynamically.

lnline frame rendering optimizations lnline frames is a technique that some web developers use to incorporate elements from

different sources into a single page. Dynamic Performance Acceleration contains

functionality to specifically optimize inline frame rendering to optimize the Time-to-Action.

Javascript inlining

Waiting on javascripts to be processed by the end user browser is one of the largest

elements attributed to longer last byte download times. To mitigate this effect, Dynamic

Performance Acceleration has the ability to dynamically and in real-time inline scripts into

the web page itself. This reduces network, server, and browser processing latencies

associated with external script fetching – all with the goal of improving the Time-to-Action.

Recursive cascading style sheet inlining

As with the Javascript inlining function, Dynamic Performance Acceleration has the ability

to inline cascading style sheets (CSS) into the base HTML page. This is done to improve

the Time-to-Action by eliminating superfluous requests and wait time.

Browser connection limit management

Not all browsers exhibit the same behaviors. Some browsers are able to support two

simultaneous connections, while others can support six or more. Dynamic Performance

Acceleration knows the capabilities of the most popular browser types and in turn is able

to override the default parameters and fool the browser into believing it has more

connections available, allowing the end user's browser to download more multiple

resources via the many connections. New browser support is added as new standards

emerge.

Compression

Compression is a very common performance optimization, but is often not used because

it can be CPU intensive. Dynamic Performance Acceleration has the ability to compress

content by MIME type as a way to reduce the overall payload size that the end user's

browser needs to download, thus improving performance.

Early resource loading

Browser think time can sometimes impact when resources load. Application Acceleration

ensures end user browsers can fetch resources as soon as page loading commences, so

as to eliminate unnecessary delays and improving Time-to-Action.

Text replacement/insertion

Dynamic Performance Acceleration also has the ability to dynamically replace and inject

code into the HTML page. This can be useful to place tracking or campaign beacons into

10 | Page

a web page. Text replacement can also be used as a means to alter hard-coded

elements in a page, such as changing HTTP to HTTPS, to ensure that end users do not

get security browser warnings.

XO CONTROL The Application Acceleration client extranet site, CONTROL, provides customers with the

functionality they need in order to self-provision and report on their Application

Acceleration service. Using a wizard-like workflow, customers can tune and manipulate

their Application Acceleration configuration. Configuration changes are propagated to the

production network in less than five minutes, allowing customers to do rapid prototyping,

as well as adjustments to their production environment in near real-time.

Summary Application Acceleration is a Software-as-a-Service (SaaS) solution designed to provide

customers with a transparent and scalable solution to enable Web Page Optimization

(WPO) to reduce the end user Time-to-Action. By optimizing the web page experience for

the end user, organizations may see a range of benefits including: • Improved Conversion Rates: Customers may see an improvement in their conversion rates

as a result of the improved Time-to-Action. Because end users can interact with the web site

faster, they are less likely to get frustrated and leave.

• More Page Views: For ad supported sites, optimizing the Time-to-Action translates to more page

views, and the more pages viewed, the more money you have the opportunity to earn.

• Enhanced User Experience: Customers have a very short attention span if a web site is

slow. Improving the Time-to-Action helps protect your brand and leaves your audience with

a positive impression.

• Stickiness/Adoption: When the perceived page load time is fast, end users are more likely to

linger on your web site. This gives you more of an opportunity to sell, promote, and/or drive

uptake of your online service.

• Reduce Abandonment: A shorter Time-to-Action will keep users on your web site and

less likely to abandon shopping carts. If users are engaged with your brand, you keep

them away from the competition.

Application Acceleration can be purchased as a standalone capability or as part of a

complementary WOC/DSA service. Whether your needs are regional, mobile, or

international, Application Acceleration fills a role that no other technology solution can

compare to in terms of scalability, ease of use, and technological capability.

11 | Page

The HTTP protocol in the end user's browser is the new bottleneck of the Internet. Using XO

Application Acceleration is the latest technology in your arsenal to over overcome the

limitations of the end user browser.

To learn more, please visit www.xo.com/SuperchargeYourContent or contact an XO representative at 888-349-0134.