optimizing the digital experience

Optimizing the Digital

Experience: A Step by Step Guide to High Performing

Websites and Web Applications

2

Published by Limelight Networks222 S. Mill Ave. Ste. 800Tempe, AZ 85281www.limelight.com

© 2014 Limelight Networks, Inc. All rights reserved. No part of this document may be reproduced, or transmitted by any means (electronic, mechanical, photocopying, recording, or otherwise) without the express written permission of Limelight Networks, Inc. Limelight Orchestrate™ is a trademark owned by Limelight Networks, Inc. All rights reserved. All other trademarks referred to herein are the property of their respective owners.

Limit of liability/disclaimer of warranty: Limelight Networks, Inc. makes no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaims all warranties, including without limitation warranties of fitness for a particular purpose. No warranty may be created or extended by sales or promotional materials. The advice and strategies contained herein may not be suitable for every situation. This work is distributed with the understanding that the publisher is not engaged in rendering legal, accounting, or other professional services. If professional assistance is required, the services of a competent professional person should be sought. Neither the publisher nor the author shall be liable for damages arising herefrom. The fact that an organization or website is referred to in this work as a citation and/or a potential source of further information does not mean that the author or the publisher endorses the information the organization or website may provide or recommendations it may make. Further, readers should be aware that Internet websites listed in this work may have changed or disappeared between when this work was written and when it is read.

L IMEL IGHT NETWORKS

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Table Of Contents

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

CHAPTER 1: Understanding Your Digital Presence . . . . . . . . . . . . . . . . . . . . 8

CHAPTER 2:What is Performance? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

CHAPTER 3:Establishing KPIs and Measuring Performance . . . . . . . . . . . 34

CHAPTER 4:How to Structure Your Technology Ecosystem . . . . . . . . . . . 49

CHAPTER 5Optimizing the Infrastructure. . . . . . . . . . . . . . . . . . . . . . . . . . . 64

CHAPTER 6Additional Optimizations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

CHAPTER 7Making the Case: Your Optimization Checklist . . . . . . . . . . 93

TABLE OF CONTENTS

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Introduction

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INTRODUCT ION

For businesses, audience

engagement is a hot topic.

Your marketing team, in collaboration with IT, is collecting

and analyzing all kinds of data on the success of web content,

social media, and its effect on audience engagement. However

there is one critical element of audience engagement that is often

overlooked: the user experience. When your audience members

attempt to access your content, how long do they have to wait

for it to arrive? The path from your content to your audience

is complex. Understanding and managing this path is critical

to your business.

This book is an introduction to the complexity of this path

between people and content. It is loaded with information

on how you can measure and increase the performance

of web content and web applications, resulting in shorter

wait times and better audience engagement. We start with

basic content, defining digital presence, and then quickly

move on to the more complex topic of understanding web

performance. We then guide you through key performance

indicators (KPIs) for assessment and ongoing management of

the digital experience of your audience. Finally, we provide

an introduction to content delivery networks and provide

more information on optimizing the delivery of both static

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and dynamic web content. We will end with an optimization

checklist to ensure you are delivering a digital experience that

meets your business objectives.

Who Is This Book For?This book is for IT staff and leaders who have one or more of

the below goals.

1. You know that online performance matters to your business

and you want to optimize website performance.

2. You manage or are responsible for the performance

of your company’s web based applications.

3. Your 2014 goals include a line item to reduce the

costs or increase the return on investments required

for online performance.

4. You want to know why certain websites get more traffic

and have better audience engagement than others, and

how to join their ranks.

INTRODUCT ION

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Foolish Assumptions • You’re a technologist who has a basic understanding of

the Internet and how it works. You may be a performance

architect, a web developer, a network architect or an IT

leader. We don’t start with the history of the Internet. We

assume you have that covered.

• You speak the language of KPI because you use KPIs to

measure the effectiveness of every IT project.

• We also assume that IT and Marketing collaborate in

your organization and we discuss how to involve key

stakeholders in the quest for optimizing the delivery of your

websites and web applications.

Let’s Get StartedEach chapter builds on the previous chapter, so we recommend

that you read this book from beginning to end for the greatest

benefit. Once you have finished this book, you can develop

and execute a digital experience optimization strategy that

suits your specific business needs. No one size fits all, but you

will know how to assess your organization’s requirements

and understand the options available to enhance web

performance.

INTRODUCT ION

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CHAPTER 1

Understanding Your Digital Presence

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Every organization has a

digital presence.

Your digital presence is the overall effect of your online

touch points. It’s your website, your Facebook® page, your

Twitter® account, your blog. It is anything you create and

deliver digitally.

To learn more about the concept of digital presence, refer to

Digital Presence for Dummies®, a Wiley Brand book brought to

you by Limelight Networks.1

CHAPTER 1 : UNDERSTANDING YOUR D IG I TAL PRESENCE

1 Jason Thibeault with Ryan C. Williams, Digital Presence for Dummies (New Jersey: John

Wiley & Sons, Inc., 2013). http://resources.limelight.com/DPM_For_Dummies

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Your digital presence is the key to your organization’s

competitive edge, and delivering it well may be central to your

professional success. The quality of the digital experiences you

create for your visitors is just as important as the quality of your

content itself. Slow response, in any form, for any reason, can

negate all the work you’ve put into telling great stories and

promoting great offerings.

Every digital presence has two sides:

• Building/Managing: This is the software you use and the

processes that you employ to actually make your website,

publish blog posts, engage with social media. This might

be a content management system or a social CRM. It is not

the intent of this book to delve into details of building and

managing your digital presence.

• Delivering/Optimizing: This is the software you use and the

processes that you employ to deliver your content to your

Building/Managing Delivering/Optimizing

THE TWO SIDES OF DIGITAL PRESENCE


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What is Performance?Performance, in a nutshell, is the measure of how well your

digital content is delivered when an end user requests it.

Maybe that’s a webpage. Maybe it’s a software download.

Maybe it’s a video. Regardless, every time a user requests

content from you, the delivery of that request can be measured.

We define performance in much more detail later in this book.

For now, just know that it’s a way to measure how well your

digital content is delivered.

Why is Performance Important?When any component of your digital presence underperforms,

the impact can hit the bottom line directly. Collaboration

stalls and painstakingly developed apps do not perform as

intended. Visitors bounce, walk away from video downloads,

and abandon shopping carts.

audience. This might be a content delivery network, cloud

storage, or optimization software. This book is focused

on helping you understand the ins-and-outs of delivering

your digital presence for an optimized user experience,

answering questions like, “How do I make my website

load faster?”


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Consider these facts:

• Every 100 milliseconds delay in load time decreases sales

by 1% (Amazon.com, Inc.)2

• 1/2 second delay in search results loading decreases traffic

and revenue by 20% (Google, Inc.)3

• 1 second delay in page-load times equals 11% fewer

page views, a 16% decrease in customer satisfaction and

a 7% decrease in conversion (Aberdeen Group, Inc.)4

• 85% of mobile users expect desktop-quality experience

(IBM Corp.)5

As you think about performance in the context of the visitor

experience, take note of the precise correlation between

milliseconds and user satisfaction. Today’s Internet visitors bring

wildly unrealistic performance expectations. A 2013 Google,

Inc. test6 identified one second (100 milliseconds) as the point

at which users react negatively to delay. This study confirms

2 Amazon.com, Inc. “Make Data Useful,” 2006. https://sites.google.com/site/glinden/Home/

StanfordDataMining.2006-11-28.ppt?attredirects=0. Accessed December 2013.

3 Greg Linden, “Marissa Mayer at Web 2.0,” November 9, 2006, http://glinden.blogspot.

com/2006/11/marissa-mayer-at-web-20.html. Accessed December 2013.

4 Aberdeen Group, “The Performance of Web Applications: Customers Are Won or Lost in

One Second,” November 30, 2008, http://www.aberdeen.com/aberdeen-library/5136/RA-

performance-web-application.aspx. Accessed December 2013.

5 IBM Tealeaf, “Meeting the expectations of the mobile customer,” May 2013. http://lp.tealeaf.com/

cem_masterclass_1.html. Accessed December 2013.

6 Ilya Grigorik, “Building Faster Mobile Websites,” (presentation, San Francisco HTML5 Meetup,

March 21, 2013), https://plus.google.com/u/0/+IlyaGrigorik/posts/WZeETYCcm1X. Accessed

December 2013.


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7 Nielsen Norman Group “Response Times: The 3 Important Limits,” January 1, 1993,

http://www.nngroup.com/articles/response-times-3-important-limits/. Accessed December 2013.

longstanding findings from the Nielsen Norman Group that

one second is the threshold at which a user loses “the feeling

of operating directly on the data.”7

In optimizing the user experience, you have to think about how

to meet unreasonable user expectations using the technology

available today. When digital experiences fail to deliver the

appropriate level of performance to meet user expectations the

obvious happens—time spent on your site drops, the number

of pages viewed diminishes, downloads of your software or

collateral dwindle.

Most organizations have a rudimentary plan in place to

mitigate web performance issues. When sites slow down, they

look at the web logs. When visitors complain about lackluster

digital experiences, they examine source code. But most of

these “strategies” are very reactive. In fact, you are probably

already optimizing your use of the public Internet, wide area

networks (WAN), and code.

So if technology is improving and networks are getting faster,

why does performance still falter? And what can you do about it?

As it turns out, quite a lot.


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The importance that users place on performance mandates

that you think about it differently, that you get out of the “break/

fix” model and into the “performance is a strategy” model.

DEMANDS ON IT MANAGERSThere is no one else on whom the burden of performance

falls more than the IT staff. Because digital is becoming such

an important part of the business, IT managers are required

to think about the end user experience like never before. So

when it breaks, you fix it. But is being a fire-fighter putting focus

on performance? Is fixing things when they break a strategy?

Challenges of PerformanceYour focus on your digital presence to date may have been

all about building and managing content: making the website

more interactive, integrating tools like online video players,

or otherwise enabling your marketing team. Delivering and

optimizing the visitor experience is just as important, but there

are challenges.


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1. Performance is complex.

Performance is often discussed in terms of speed: how quickly

a system responds to a user request, how quickly bytes move

across the network, or how quickly images render in the browser.

And speed is an important aspect of performance, perhaps

the most important. But from a user perspective, performance

is more about “wait.” In addition, issues like availability, multi

device delivery, and security come into play. Chapter 2 of this

book will propose a more complete definition of performance,

one that considers all of these factors.

2. Performance is notoriously difficult to measure.

Knowing where to focus your performance improvement

efforts requires you to identify the precise bottlenecks and

points of failure in a complex digital landscape. But how do

you measure performance success? First byte response time?

Increased average revenue per user? Or something else? If

you are responsible for improving performance, then you want

to know how to measure it accurately. In Chapter 3 of this

book you will learn how to realistically approach performance

testing, and which bottlenecks are worth the chase.


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3. Improving performance requires new technologies and

partnerships.

Marketing departments need to speed the flow of engaging

content to capture and retain audience attention and build

relationships across digital channels. The fulfillment of that need,

more often than not, falls to IT. CTOs, CIOs, network engineers,

web developers, and others are thinking as much about

servicing external audiences as internal, and in an entirely new

way. In Chapter 4 you will learn how to go about structuring your

technology ecosystem to support these changes.

4. The network that delivers your content is slow and invisible.

There is a vast, un-optimized stretch of public Internet between

your origin servers and the access networks that connect you

to your end users. It is made up of overlapping networks and

carriers to support long haul, regional and metro traffic. It was

built to be resilient, and has proven so. Other than compressing

files and optimizing scripts, how much control do you have? Do

you have insight into the path your content takes to reach end

users with their multiple locations, devices, and browsers? How

do you protect your content from security vulnerabilities along

the way? We will explore this topic in Chapter 5.


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5. Dynamic content is exploding.

Certainly your digital presence has evolved to the point that

much of what a visitor experiences is dynamically created and

presented on the fly - just for them. And multiple technologies

are required to support dynamic websites and apps. Chapter

6 of this book covers the technologies required to optimize

dynamic content and create the experience you as an IT

manager are responsible for delivering.

Is There a Solution?Are there ways around these problems? Certainly. You could

achieve significant performance gains with worldwide data

center build outs: servers on every continent, storing and

delivering your content at local speeds to global users. Of

course, few organizations have the resources to build such a

superhighway on their own. The capital investment required to

get the project off the ground, not to mention the expertise and

resources required to maintain it, has understandably put this

solution out of reach for most content providers.

But what if you could, in effect, get the same thing through

a partnership? What if you could have what amounts to a

phalanx of data centers serving your content from locations

close to your website visitors wherever they may be, and then


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link these data centers along a private high speed network?

Then, you would not have to live by public Internet rules. By the

time you are finished reading this book, you will know what

you can do to drive performance not just at your origin or in

your user’s browser, but along the entire length of the content

delivery path.

What You Learned and Next StepsIn this chapter, we defined digital presence and showed that

your digital presence is comprised of two facets—building/

managing and delivering/optimizing. Delivering and optimizing

your digital presence requires a strategy that incorporates

performance into its very building blocks.

You also learned that optimizing the audience experience is

critical to you and your business. But it is difficult. A complex

delivery landscape and new technologies create significant

challenges.

Regardless of whether you are thinking about doing it all

yourself, just doing part of it in-house augmented by partners, or

even outsourcing the entire process, you need to build a digital

experience optimization strategy to stay competitive. The first

order of business is to understand more about performance and

the factors that affect it. That is where we will begin in Chapter 2.


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CHAPTER 2

What is Performance?

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CHAPTER 2 : WHAT I S PERFORMANCE?

Very few organizations in the

world can effectively optimize

the digital experience all by

themselves.

For the vast majority, they need partners to ensure the best

possible end user experience. In Chapter 1 we briefly defined

performance as the measurement of how well your digital

content is delivered when it is requested by an end user. But

to truly understand performance, you must look into the vast

network that delivers your content. This network is composed of

three distinct segments: the first mile, middle mile, and last mile.

These segments connect audiences from their devices through

content delivery networks or the Internet to your valuable

content. The quality of your end user’s experience results from

the performance along all three segments. You already know

that a large portion of the network is beyond your control. But

by controlling more aspects of the content delivery path, you

can better optimize performance.

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Rethinking Web PerformanceToday, web performance is often synonymous with just speed.

Many organizations define web performance as a measure

of how fast the website loads according to server side data

collection. This definition of web performance is very limiting

because it does not take into account what is happening

across the entire delivery path, all the way to the end user. Are

they on a mobile network? Is their computer running slowly?

Yes, it is critical to understand how quickly internal systems are

responding. But it is just as critical to understand how users

are interacting with content when it is delivered. Defining web

performance based purely on server side data does not

present a whole picture of the digital experience.

Web performance, from a technical perspective, is really about

responsiveness. How fast does an object render in the browser?

How fast does DNS resolve a request? What is the difference

in time between when a user requests something and when a

system responds? But from a user perspective, performance is

more about “wait.” How long did I have to wait before I could

start that video? How long did I have to wait for that button to

appear before I could click on it?

The web team may have optimized the website or app but

users are frustrated that they still have to wait for content to


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appear. What could be happening between these points-the

origin server and end user-to cause delay?

The Complex Path of Content DeliveryThere are constantly changing external factors impacting

your web performance right now. As content becomes more

personalized, online interactions more complex, Internet traffic

heavier and requirements more real-time, there is a huge ripple

effect across the network that delivers your content.

Each segment of that network is defined below. The network

segments are usually discussed in sequence from last to first

because a user’s experience begins not at the origin server,

but at the first attempt to access content in the last mile.

• The last mile is when content and content requests travel

between your user’s Internet service provider (ISP) or

mobile access network and their device. What happens

in the last mile in terms of performance is dictated by more

than the speed of your user’s access network. Your user’s

device type, operating system and browser all play a role,

and so does the distance content must travel across the last

mile access network to arrive at your end user.


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• The middle mile is the longest network segment,

spanning the distance between your end user’s access

network and the server where your content is stored.

If your content is stored in an edge server near your

end user, then the middle mile is the distance between

that edge server where content is cached and the server

where it originated (referred to as the origin). Otherwise,

the middle mile is the distance directly between your user’s

access network and your origin servers—in other words,

the public Internet: a collection of networks maintained by

various third parties that cannot be seen or controlled by

most organizations. It’s made up of overlapping networks

and carriers to support long haul, regional, and metro

traffic. Think of it as international freeways, highways and

city streets, all owned by different transit systems. And

dispersed throughout these different transit systems are

Internet Exchange Points (IXPs), where different networks

agree to exchange traffic. Depending on where your

online audience is located, there may not be a direct route

between your origin servers and your website visitors across

the middle mile. That means your content may be routed

across different networks to get to your website visitors or

app users.


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• The first mile begins at your origin servers and extends to

the point where you give up control to another party. In

the absence of a content delivery network (CDN), the first

mile is the distance between your origin server and the

transit provider that moves content toward your end user,

or perhaps to another data center in your own network.

In the event that you are using a CDN, the first mile is the

distance between your origin server and the CDN’s origin

server. Ideally, the first mile is short; the closer your servers

are to the point at which you hand off content to another

party, the lower the latency. In Chapter 5, we will talk more

about CDNs.

Performance Bottlenecks for Content DeliveryEach network segment introduces unique performance

bottlenecks. To understand and thus improve performance, you

must know what these bottlenecks are and where they can

Last Mile Middle Mile First Mile


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occur along the content delivery path. Let’s examine them in

the context of the three distinct network segments.

1. Last mile: This is the zone most prone to performance issues

that can go undetected, but impact the user experience in

an exponential manner. These bottlenecks are in the final hop

between your end user’s device and ISP or mobile access

network. They include latency, congestion, browser diversity,

content complexity and content structure.

• Latency: Latency is the biggest performance killer in the last

mile. Even if broadband penetration is increasing globally

through DSL and cable networks, end users increasingly

access your content through multiple devices like mobile

phones and tablets, over wireless connections. Wireless

networks introduce hundreds of milliseconds of latency.

Delivering an object just a few miles across a wireless

network can introduce as much latency as delivering that

same object halfway around the world across a wired

connection. In the face of high latency, Internet protocols

reduce throughput—a vicious cycle which can damage

performance even further.

• Congestion: Bandwidth availability is high, and increasing

worldwide. However, traffic can still exceed capacity

in certain situations. Particularly in emerging markets,


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oversubscription poses a major problem. Requests from

hundreds of thousands or even millions of end users may

all be converging on the same 1-gigabit-per-second link

exiting the region. Flash crowds converging on a particular

piece of content can also cause congestion; if a single

video file becomes popular in one location, bandwidth to

access that file may be constrained.

• Browser diversity: Trying to keep up with optimizing content

to perform well on every type of browser (and every version

of those different types) is a losing proposition; even the

world’s most talented developers have yet to outsmart

the browser game. In fact, the mechanisms that your

developers are putting in place to optimize performance

for certain browsers today may turn out to be performance

inhibitors when the next version of the browser is released.

For example, a practice known as domain sharding first

emerged to circumvent older browsers’ two connections

per server limit and increase parallelism. Modern browsers

have raised that limit to six or more connections. So

unconditionally implementing this supposed best practice

could cause problems.

• Content complexity: The number, type, and nature of

the components at work in a given website or app has

significant implications for performance. Web 1.0 and Web


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2.0 users self-guided their digital experiences, navigating

to and through websites and apps to find specific content.

But these days, the content guides the user—delivering

search results based on user profiles, creating personalized

journeys through websites based on individual preferences,

and otherwise shaping the digital experience. This level

of personalization involves a huge amount of dynamic

content, which in turn means more round trip requests are

traveling across the Internet to more servers for more users

than ever before.

• Content structure: A simple webpage can contain tens of

styling libraries, which introduce round trip time delays and

have different execution times. These libraries load up in

the order they are downloaded, forcing end users to wait

before they can interact with the page. And as user devices

become more and more capable of displaying high

resolution media, more and more high resolution media is

used—consuming browser resources and bandwidth. This

runaway train concept is illustrated in the graphs on the

next page; even though the number of image and object

requests has remained relatively flat year over year, the

average size of images and web objects has increased

disproportionately.


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2. Middle mile: Now that you understand last mile performance

issues, we will take a look at the middle mile. Whereas ISPs and

mobile networks have an incentive to improve performance

across the last mile of the delivery path, the middle mile is a

different story. It can be a vast, un-optimized, and ungovernable

stretch of public Internet over which you have absolutely no

control. It is also where HTML chattiness and TCP latency pile

up fast. Every request that travels back to the origin must cross

the middle mile, and is subject to the performance threats

1000kB

900kB

800kB

700kB

600kB

90

80

70

60

50

4011/1 12/1 1/1 2/1 3/1 4/1 5/1 6/1 7/1 8/1 9/1 10/1 11/1

753kB

53 54 54 54 55 55 56 56 56 56 56 55 55

779kB 793kB 790kB812kB

853kB 872kB891kB

909kB932kB

951kB 970kB

2000

1500

1000

150

130

110

90

70

11/1 12/1 1/1 2/1 3/1 4/1 5/1 6/1 7/1 8/1 9/1 10/1 11/1

1249kB

86 88 88 88 90 90 91 92 93 94 94 94 95

1285kB1284kB 1270kB 1311kB1400kB 1427kB 1462kB1485kB

1521kB1551kB1590kB11614kB

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Image Transfer Size (kB) Image Requests

Total Transfer Size (kB) Total Requests

Image Transfer Size and Image Requests

Total Transfer Size and Total Requests

Data from the HTTP Archive shows the year-over-year rise in average image

size and total transfer size of web based objects from 2012 to 2013.1

1 Courtesy of HTTP Archive, http://httparchive.org/trends.php#bytesImg&reqImg.


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that occur along the way. Middle mile latency, complex

network connections, content rules and network equipment

configurations all affect web performance.

• Latency: Not just a last mile problem, latency in the middle

mile is also a performance killer. Requests and data

moving from end user access networks to your origin and

back can travel through dozens of networks in just one

round trip. Transmission control protocol (TCP) only allows

those requests to be transferred incrementally, and limits

the amount of data transferred during each request or TCP

window. Any amount of packet loss requires retransmission,

which further decreases throughput. Latency inducing

round trip time (RTT) increases and performance suffers.

• Lack of control over network types: The biggest portion of

the Internet resides between your ISP and your end user’s

access network. Many heterogeneous networks, Border

Gateway Protocol (BGP) sessions, public routes, latency,

packet loss and variance in quality of service (QoS) affect

your content in the middle mile.

• Content rules: Caching behavior (cache control headers)

can easily be manipulated by a malicious proxy sitting

in the middle mile, causing performance issues on HTTP

traffic. Poorly configured websites and applications may


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have many fragmented components including scripts,

stylesheets, and images, mostly in an HTML container. The

way that browsers request sequentially and in parallel

adds many round trips to render a webpage. The simple

formula for latency can thus be attributed to two main

factors: latency between two nodes, and the number of

round trips required.

• Network equipment configuration: Fewer hops do not

necessarily mean that content is transferred more quickly.

Two hops across a path that has high latency and packet

loss are inferior to three hops across a faster route.

Depending on how equipment is configured, content may

not be moving efficiently across the delivery path.

3. First mile: The first mile is the third segment of the delivery

network that we will discuss in terms of performance bottlenecks.

Many organizations spend considerable capital on both the

development and maintenance of IT resources at their origin,

where the first mile begins. These resources include custom

developed applications, servers, data centers and networking

equipment like routers and switches. And every one of them

is performance sensitive. Complex technology ecosystems,

network device resource limitations, web server resource

limitations, content rules, and SSL processing all have an impact

on first mile performance.


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• Complex technology ecosystem: Many IT resources are

custom developed applications built on a mix of varied

technologies like PHP, J2EE, and .NET frameworks. Utilizing

fragmented technologies not only adds complexity to

your design and architecture, but protocol differences can

also lead to performance degradation. Lack of software

integration on the digital presence management side can

mean that information is not shared among sales and

marketing automation, CRM, content management, and

other platforms—limiting insight into performance issues

and creating a disjointed end user experience.

• Network device resource limitations: Hardware devices

such as servers, switches and routing equipment have

limited computing memory; if they are not optimally load

balanced, they can become quickly overloaded with

a simple web application clocking a few million hits a

day. Overhead, such as compressing content (think the

Gzip approach), reduces the payload size and forces a

tradeoff between server consumption and performance.

Load and reduced file transfer size could be the key

difference between a highly optimized origin server and a

misconfigured one.

• Web server resource limitations: Most webpages and

applications that are hosted on your equipment have


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transaction-completion-time boundaries. Assets like script,

images, and stylesheets have to be fetched and served

over the wire in milliseconds. The cycle repeats millions of

times per day (billions for popular applications). But when

RAM and available CPU capacity are limited, a database

query, disk read/write or a cached response could be the

difference between increasing and reducing response time

by several seconds.

• Content rules: A server has to set content rules on caching

and how much time an object can be retained in the

browser (called time to live or TTL) before sending a request

to refresh it. Each refresh request adds a read/write load to

all of the components of your origin: router, storage disk,

bandwidth and CPU.

• SSL processing: SSL transactions have more server

consumption and utilization than normal transactions, and

they are time sensitive. Using the same CPU for concurrent

SSL transactions introduces latency in the overall system

due to extra steps required in authentication, certificate

handling and digital handshakes.

With so many bottlenecks to overcome, it’s no surprise that the

world’s leading web performance experts have shifted from

advocating “hand-tuning” to implementation of automated

web performance optimization technologies.


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What You Learned and Next StepsEven if all of your resources are optimized at the origin,

there are many external moving parts in the last, middle and

first mile network segments that undermine performance.

The performance bottlenecks in each network segment

can reduce the speed and availability of websites and

web applications, limit scalability, inhibit delivery to certain

devices, and reduce end user engagement levels. With so

many factors impacting performance and so much of what

happens to your content seemingly out of your control,

how do you go about formulating a digital experience

optimization strategy that supports performance? Identify

your KPIs.

Measurement is perhaps the most critical component of

ensuring that your end user experience is optimized. But what

do you measure? And, more importantly, how do you know if

what you are measuring is the right thing to measure? Read on

to find out how setting KPIs will help you create a “measurement

framework” that will guide your future content delivery decisions.


34

CHAPTER 3

Establishing KPIs and Measuring Performance

35

CHAPTER 3 : ESTABL ISH ING KP IS AND MEASUR ING PERFORMANCE

Now that you understand the

forces driving the need for

high performance and the

factors that influence it ,

you can begin to formulate a strategy to improve the delivery

of your content for an optimized user experience. This strategy

starts with establishing key performance indicators (KPIs).

Performance KPIs are not the same to everyone. Marketers,

for example, consider the number of visitors an important KPI

for their website. Web developers might consider “time to first

paint” as a KPI. That’s why you need to define what delivery

optimization means to you. Is it a faster shopping cart? Is it

more time spent on each page? Is it more pages viewed?

Whatever the metrics you define, they need to reflect what you

expect from web performance optimization efforts. Your KPIs

will determine how your organization measures performance

success. So, establish a baseline set of KPIs and then test

performance using real user measurements (RUM).

36

Baseline KPIsBefore you start pulling server logs and utilizing third party

services to gather client data, you need to have a baseline set

of KPIs. What are acceptable numbers for your KPIs? Is 1,000

new visitors each day an adequate number? Is 36 seconds

enough time spent on each page? The point of setting

baselines for your KPIs is that it gives you something against

which to gauge improvements.

In thinking about baseline performance testing, it’s important to

understand one critical aspect: Performance is about more than

speed alone. As we discussed in Chapter 2, multiple factors

impact the delivery of your content. That’s why establishing a

baseline is so important. That baseline allows you to continually

monitor every aspect of your user experience and improve

upon the parts that matter most.

Focusing your digital experience optimization strategy on

a single type of KPI not only provides an incomplete picture

of performance; it undermines it. For example, delivering

a user experience that is fast (focusing on speed) but

doing so inconsistently (overlooking availability) has a net

negative effect.

How do you chose your performance KPIs? Generally speaking,


37

performance related KPIs can be grouped into five categories:

• Speed

• Availability

• Scalability

• Multi device support

• End user experience

Speed: As you have learned, speed is the most commonly

used indicator of performance. The primary ways to measure

speed are a system’s responsiveness to a request, and the

end user’s ability to interact with content once that response is

completed. Therefore, KPIs for speed may include:

• Connection time

• DNS lookup time

• Download time

• First byte response

• Latency

• Page load time

• Response to request time

• Throughput

• Time to first paint

• Time to interaction

Availability: Availability is a given; your content must be

consistently available and secure at all times. If visitors go to

your website and cannot find the content desired, they are


38

gone, possibly forever. There are too many alternatives out

there. In this case, speed has little to do with it. You need to

make certain that your website, content servers, and network

links are always up and running. Availability based KPIs

may include:

• Error rate

• Packet loss

• Security event response time

• Uptime

Scalability: Your ability to accommodate changing needs and

traffic patterns is highly correlated to the quality of your users’

experiences over time. Distributing or removing content for

audiences of highly variable behavior patterns, sizes, locations,

and access devices requires elasticity. Knowing the capacity of

every component in your technology ecosystem ensures that

flash crowds and traffic surges will not pose an issue. Scaling

down is equally important; unless traffic is 100% consistent,

building out your own infrastructure for peak capacity is going

to yield poor return on investment. KPIs around scalability may

include:

• Backlogs

• Bandwidth utilization

• Failover recovery time

• Source of demand


39

• Source of load

• Storage utilization

• Uptime versus traffic

Multi Device Support: It is not just the number of users

accessing your content that creates performance challenges,

but the proliferation of different types of devices, with different

browsers and operating systems. Each device has its own

presentation requirements, processing, caching, storage,

and networking capabilities, which influence performance.

Some can open multiple concurrent connections, others just

a few. Similarly, some can cache a large number of objects,

others just a few. If your audience is using multiple devices or

platforms, remember to measure performance across each

one. You will apply KPIs in the categories of speed, availability,

and scalability to every device your audience uses. These

may include:

• Error rate for mobile content

• First byte download time

• Initial connection time

• Mobile redirect time

• Number of page views

• Support for multiple devices

• Time to first interaction

• Transaction completion rate


40

End User Experience: Ultimately, organizations work to

improve performance in the interest of the end user. Machine

metrics such as error rate or site load time are valuable, but

they exist only as indicators of how easily your audience can

locate and interact with your content. KPIs associated with the

end user experience signal how usable, relevant, and valuable

your content is. Examples are listed below; later in this chapter,

we will discuss the best methods for monitoring end user

experience on an ongoing basis.

• Abandonment rate

• Average revenue per user

• Bounce rate

• Completed tasks

• Conversion rate

• Engagement score

• Repeat visits

• Time on site

Rather than just speed, the “true delivery performance” is

a holistic measurement combining KPIs from all of these

five categories: speed, availability, scalability, multi device

support, and end user experience.


41

THE OPTIMIZED EXPERIENCEWhat does a successful visitor experience look like? Here are

two real examples, each with unique KPIs—including more than

just speed.

SoundCloud®: SoundCloud is the leading audio platform

that gives users unprecedented access to the world’s largest

community of music and audio creators. Twelve hours of music

and audio are posted every minute. 90% of tracks get played,

most on the day that they’re posted—more than half within the

hour that they’re posted. SoundCloud must deliver more than

speed; its KPIs also include reliability (an uninterrupted listening

experience) and scalability (the ability to accommodate traffic

spikes when a track goes viral). Focusing solely on speed would

shortchange SoundCloud’s overall performance.1

HBO GO®: Reliability and multi device delivery are critical for

this cable television site. HBO GO is part of HBO’s TV Everywhere

platform, which allows users to stream HBO content on nine

popular devices including mobile phones, tablets, e-readers, and

gaming consoles.2 Minimizing error rates (reliability) across these

devices (multi device support) is an important KPI for HBO GO;

both encompass more than raw speed.

1 Information courtesy of SoundCloud.

2 Gina Hall, “Will HBO Go come to the masses?” L.A. Biz, September 26, 2013, http://www.bizjournals.com/losangeles/news/2013/09/26/will-hbo-go-come-to-the-masses.html. Accessed December 2013.


42

Evaluating Performance

Performance is not a one-time engagement. In the same way that

you should expand the KPIs you use to measure performance,

you should expand the testing window. Once you establish

baseline KPIs, you will continually monitor and evaluate progress,

diagnosing and re-diagnosing performance issues.

One common way to measure performance is to log on to the

company website or portal and take note of response time. For

many IT managers who log on to the corporate network directly

connected to the content origin server, performance seems

good. It can come as a surprise when one of the organization’s

road warriors complains about poor web performance at a

distant customer office. “Hey, it was fine a moment ago when

I logged on!” the IT manager replies. But one thousand miles

away, even one hundred miles away, that is not necessarily

the case. That is because on-site testing bypasses the middle

mile altogether—that vast, un-optimized stretch of public

Internet that has such a major impact on performance. The

optimizations you made on the development side make no

difference when you deploy in production, because too many

bottlenecks occur in the real world environment.

In truth, you generally cannot experience your website

performance from corporate data centers the same way your


43

audience experiences it. You can have the most blazing fast

delivery on the server side, but find out that objects are loading

slowly in web browsers because they are not optimized. Or,

the wrong things are loading in the wrong order. If nothing

else, the latency resulting from distance adds a few seconds,

even just a few milliseconds; still, it is enough to push user wait

times into the noticeably unacceptable range.

Another common way to measure website performance, used

by most web teams, is synthetic monitoring. Using a testing

agent, scripts are run that simulate the actions a site visitor would

likely take. The monitoring provides usage data, showing if the

site is up and how its most common processes are running. This

is great for testing your raw speed in the absence of variables

such as browser protocols. But it does not really provide a

good sense of user wait times since real world factors are not

part of the equation. And because it is pre-scripted, it cannot

mimic the random and erratic paths users typically take.

Meanwhile, Internet service providers (ISPs) and mobile access

networks do not know the real performance they deliver. At best,

they have synthetic simulations or backbone testing, where test

agents are inserted into major points deep inside the network.

With backbone testing, however, you are testing performance

at the big hubs, where Internet network speed is essentially

infinite and would rarely become bottlenecked. In effect, you


44

end up monitoring the delivery speed of individual objects in a

vacuum, without taking into account neighborhood issues with

ISPs or individual connectivity to any of those networks. In the

end, you are measuring a network—not what your audience

actually experiences. Even putting agents out in the last mile

does not provide a complete picture of performance.

Optimizing Measurements for Real UsersOperational system metrics gathered from your own infrastructure

will tell you how your internal systems are performing. Synthetic

usage data indicates how well you are delivering your content

to machine testing agents. Application data such as CRM reports

can reveal how your audience is reacting to your content.

But only user centric metrics will reveal if the user experience will

improve as a result of your digital experience optimization

strategy. The best option to measure performance with a user

centric approach is with real user monitoring (RUM). RUM is a

type of reactive monitoring mechanism. It monitors actual user

interaction with a website or application. RUM is critical to truly

understanding the end user perception of the digital experience. It

answers questions like: Is the element that users are expecting to

load not available until the website has completely rendered?


45

Are there errors occurring? Is there a business process (i.e., sales

funnel) failing?

RUM functions by injecting a small piece of code, typically

JavaScript, into the digital touch point you want to analyze;

a webpage or media player, for example. The code captures

statistics like available bandwidth, CPU usage, time to action

and similar trends. It records and relays download times and

task completion times and flags certain events if they are not

within the normal threshold. It then relays these details to help

build beacons. RUM testing can be performed in-house or by

a specialized third party provider.

The most compelling feature of RUM is that it provides

feedback on performance as seen by actual users, giving you

a sense of how your content will actually perform when users

are interacting with it. It captures specific details like type of

device, browser choice, and ISP. Since it can be embedded

LOAD TIME: 6.7sec LOAD TIME:

7.2 sec

LOAD TIME: 4.6 sec

REAL USER MONITORING (RUM)


46

into any webpage, you do not have to generalize and guess

about overall performance based on the limited metrics made

available by a few pages or transactions. With RUM, any page

or transaction can be analyzed by geographical location, IP

blocks, and regions.

RUM gives you the best chance of understanding the end

user experience without actually having to test it from a hotel

room or coffee shop hundreds or thousands of miles away.

Combined with operational system metrics, synthetic data, and

application data, RUM gives you the insight you need to know

if your performance optimizations are really working.


47

HOW EFFECTIVE IS YOUR VISITOR EXPERIENCE? Logging onto your website from the office will tell you if your site is

up and running, but not end user wait times. These tools can show

you how others experience your website in the real world.

HTTP Archive: Enter any URL to view granular data such as

millisecond-level screen shots, or larger trends in transfer size and

request. http://httparchive.org/websites.php.

Gomez®: Test your total page download time with details by

object type from locations across North America, Latin America,

Europe, and Asia Pacific regions. http://www.gomez.com/website-

performance-test/.

Keynote®: Download free apps (including mobile and Internet

testing environments) with a focus on real user monitoring.

http://www.keynote.com/.

Webpagetest: Test your webpage by browser and mobile device

type. Create a video file of the filmstrip to include in presentations.

http://www.webpagetest.org/.

Most performance test results are presented in the form of a waterfall

chart. A waterfall chart measures time to execute each step of the

page load: DNS lookup, TCP connection, first byte, throughput, and

download. This is useful information for identifying bottlenecks, but

remember that performance is more than just speed.


48

What You Learned and Next StepsWhat really matters in all of this is the end user experience.

You can have the biggest data center, pay for huge network

pipes, and code the slickest content, but if your end users

are experiencing unacceptable performance, none of the

rest matters. Delivering your content in the best way possible

means identifying baseline KPIs that span the categories of

speed, availability, scalability, multi device delivery, and end

user experience.

With RUM, you have a tool that can guide your understanding

and measurement of user wait times. Now that you have

KPIs defined and baselines established, how do you improve

performance and nullify those wait times? You will need to

build a technology ecosystem to support performance for the

long term. This is where we will begin in Chapter 4.


49

CHAPTER 4

How to Structure Your Technology Ecosystem

50

The previous chapters have

given you a good sense of

how well you are delivering

your content to your

audience today.

You understand what bottlenecks stand in the way of high

performance, you have defined baseline KPIs, and you have

looked into RUM testing. Now you can choose the tools and

technologies required to further optimize web performance

and reduce user wait times.

Further optimizing performance requires an entire partner

ecosystem. You do not want to do it alone. Five years ago, in-

house optimizations were often the first line of defense against

poor web performance. But today, in-house performance

optimizations are just a starting point. With the rise in dynamic

content and rich media, increased traffic on the public Internet,

the need to reach a global audience, and the proliferation of end

user systems and devices, few IT departments can fully optimize

web performance on their own. The performance challenge is

also magnified by the continuous evolution of technology itself,

which is constantly reshaping the landscape of the digital world.

CHAPTER 4: HOW TO STRUCTURE YOUR TECHNOLOGY ECOSYSTEM

51

To choose the right partners, it is important to examine your

content mix by conducting an audit to identify requirements.

You will want to collaborate with other stakeholders during this

process and ensure cross-functional alignment.

Conducting a Content AuditTo build a partner ecosystem that supports performance, you

and other performance stakeholders in your organization

have to understand your content: how much you have, where

it resides, how it is stored and protected, the format and data

types, frequency of access, whether dynamic or static; anything

you can use to characterize your content will ensure that you

address the right issues as you build out your infrastructure to

support your KPIs.

Suppose that you have a KPI around speed and multi device

delivery. Your objective is to reduce latency by 20% on mobile

devices. RUM tells you that your mobile users are experiencing

five to seven second delays versus desktop users. Now what?

A content audit can provide you and your potential partners

with insight into what bottlenecks may be standing in the way

of your objectives. Suppose an audit of your mobile site reveals

multiple dynamic thumbnails being refreshed on every request.

The resulting round trips back to origin could cause potential


52

server overload and delay delivery—problems that require a

very different solution than on-demand rich media files would

require, for example.

The below five-factor framework will guide you through the

process of auditing your content for performance.

1. Target device

How does your audience consume your content? Most IT

managers are responsible for delivering content to more

than one type of user device. Even if you deliver content to a

dedicated device type, such as a gaming console, chances are

that there is more than one version of the device on the market.

Your technology ecosystem will need to include technology

that supports every user device—past, present, and future.

2. Content type

Dynamic and static content each present unique delivery

challenges. Delivering dynamic content can involve constant

round trips back across the middle mile, to origin servers, to

retrieve the most current version of a file. Static content, on the

other hand, can be cached closer to end users, and optimized

using different techniques. As you consider which technologies

you will select to optimize both static and dynamic content,

keep in mind that some technologies are capable of delivering


53

both types of content, but not necessarily accelerating that

delivery—a critical distinction.

3. Size

The structure of your technology ecosystem may vary depending

on the size of objects you deliver: small, or large. Small objects

such as HTML, CSS, scripts, text, and low resolution images

each take up a single CPU cycle; without proper optimizations,

they have an aggregate negative effect on performance.

Large objects such as rich media files and software updates

require different optimizations, such as caching and progressive

download. If your content mix includes both small and large

objects, then selecting a delivery partner with the capability to

optimize both large and small objects is important.

4. Media type

Are you delivering rich media? A large number of video files

in your content mix requires video-specific storage and delivery

solutions such as media servers, and specific optimizations

such as adaptive bitrate streaming. And whether you deliver

live video or video on demand (VOD) impacts how you will

ingest, encode, and replicate files. A technology system that

is not specifically designed to support rich media may hinder

performance when rich media is introduced.


54

As you can see, not all content is optimized the same way. As

you prepare to discuss your digital experience optimization

strategy with internal and external stakeholders, your content

audit will guide the conversation.

Getting Buy-in from Internal StakeholdersYou will benefit greatly from discussing the results of your

content audit with internal stakeholders across the four key

digital content functions: creation, management, delivery, and

optimization. What systems are these stakeholders using now?

And do those systems improve or undermine the delivery of

your organization’s particular content mix?

Below is an overview of each function, and how it relates to

performance.

Creation: Content creators can be external—such as

customers submitting user generated content via an app—

or internal—such as the multimedia team producing videos


55

to post on your website. Internally created content is most

often the work of the marketing team, directly or indirectly.

(Other teams may be involved, too: sales teams build training

video libraries, product teams release software updates,

and accounting teams develop online billing systems.) If

you have conducted a content audit, you already know

the characteristics of the content that you need to deliver;

working with content creators gives you foresight into how

that may change in the short and long term, so you can plan

capacity accordingly. A global marketing campaign, a new

software release, or a live event can all have a tremendous

impact on performance. Building a technology ecosystem

that can support your evolving needs requires input from

content creators.

Management: Responsibility for content management, such as

maintaining the corporate website, varies from organization

to organization. It most commonly falls to IT, marketing, or a

combination of the two. Cross-functional scenarios are also

common; for example, IT may be called upon to troubleshoot

but is not responsible for the day-to-day management

of an organization’s website. Content managers have a

significant stake in the technology ecosystem; your storage

solution, for example, will need to be universally accessible to

content managers.


56

Delivery: The delivery of digital content nearly always falls to IT.

That includes your networking group, storage team, database

group, developers, and others. Though non-IT teams contribute

and manage content, it is virtually guaranteed that it is IT’s job

to ensure that the right systems are in place to deliver it, and

deliver it fast. From video storage and streaming, to website

acceleration and CRM software, IT will take the call if something

goes wrong. You therefore have a significant role in selecting

and purchasing the solutions required to deliver content

(though other departments may have a say in the process).

Optimization: Optimizing performance is a discipline, not a one-

time engagement. It really spans the building, management,

and delivery of content. Optimizing content for the best

possible performance should be an ongoing organizational

effort; it must be continually revisited and re-evaluated by cross-

functional teams. Performance optimizing initiatives may begin

with IT, but over time the success of your digital experience

optimization strategy is a shared responsibility among multiple

stakeholders.

A Partner EcosystemNow that you have completed your content audit and you

have involved all the right stakeholders, it is time to look at

your infrastructure.


57

Recent research suggests that IT spending is shifting from

traditional IT infrastructure to infrastructure focused on the

various aspects of an organization’s digital presence. This is a

natural evolution, considering that performance has become

absolutely vital to organizational success and IT controls only

the first mile of the content delivery path (from the origin to the

point where it is handed off to a third party network). This shift

in budget also reflects the reality that high performing content

has the ability to drive revenue in many industries in ways

conventional IT infrastructure never has. This new infrastructure

requires a new partner ecosystem to support it. The ecosystem

is made up of hardware, software, and networks. It is distributed

on premise and in the cloud, and leverages in-house and

partner solutions.

In its simplest form, the ecosystem consists of a central platform

that integrates with the various systems required to build,

manage, deliver, and optimize a digital presence: analytics,

social networks, video management systems, web content

management systems, content delivery networks, social

customer relationship management (CRM) tools, sales force

automation (SFA), marketing automation, and others.

CONTENTMANAGEMENT

SFA/CRMCDN MARKETINGAUTOMATION

SOCIAL VIDEOMANAGEMENT

ANALYTICS SOCIAL CRM


58

But too often, organizations must try to cobble these systems

together, with unsatisfactory results. Either the APIs are not good

or pathways are incomplete. The effort quickly becomes time

consuming, labor intensive, and costly—while still failing to

deliver results. You may find yourself unable to perform small

tasks without disturbing the delicate balance created by the

varied software, hardware, and networks that make up your

ecosystem. Moreover, you have no insight into how systems are

working together to improve or undermine your performance.

Analytics Social Video Content CDN

Socia

l CRM

SFA

/CRM

Mar

ke

ting

M

anagement M

anagement

A

utom

ation

Digital PresencePlatform


59

Optimizing Your InfrastructureThe right partner ecosystem reins in the complexity of the digital

world with its multitude of tools and technologies and seemingly

constant proliferation of services. It not only integrates services

and technologies that plug into it, but enables you to extend

the digital platform to other systems too.

The technology ecosystem required to deliver a superior digital

experience must seamlessly integrate the tools used to build,

manage, deliver, and optimize your organization’s digital

presence.

As the previous illustration visualized, we’ve identified a number

of categories that make up a digital presence ecosystem:

• Analytics

• Social

• Video management

• Content management

• CDN

• Social CRM

• SFA/CRM

• Marketing automation

There are numerous vendors offering these services. A quality

platform can integrate fully with the components of your


60

ecosystem. Just as importantly, the platform should provide

you with access to the portions of the delivery path that are

otherwise unreachable to you—everything past your origin.

It is within the unique purview of a content delivery network

(CDN) to improve performance across the entire delivery path.

The CDN is the cornerstone piece in your performance mix.

In Chapters 5 and 6, we will discuss the technologies that

CDNs and content acceleration service providers can utilize to

improve the performance of your content.

CLOUD OR ON PREMISE?Many organizations today are opting for cloud-based software

that they can integrate through Application Programming

Interfaces (API). This enables the software to be more scalable,

reliable, and available. What’s more, the organization is

not responsible for upgrades and many software-as-a-

service (SaaS) providers integrate security into their offerings.

Evaluating Ecosystem PartnersSo what should you keep in mind as you look for partners?

We’ve assembled six key things to consider:

Integration. The platform must not only integrate services that

are connected to it, but it must provide a framework that


61

enables you to extend the platform to other systems. It must be

flexible in design.

Manageability. The platform and services that are connected

to it must include elements of management (i.e., through

application program interface [API] or graphic user interface

[GUI]) that enable you to control access, security, distribution of

content, etc.

High Performance. The platform must include technologies

and features that actively work to increase the speed and

performance of delivery to your end user. Your users won’t wait.

Resiliency. The platform must not only respond favorably

to outside pressures (e.g. a DDoS attack), but the individual

components must work independently enough that a problem

with one component does not bring down the entire platform

(e.g. loose coupling).

Elasticity. The platform must be able to scale up or down

based on demand. For example, storage should increase

naturally to accommodate increased numbers of online assets

or decrease as those assets are removed.

Future Proofing. The platform must continually adapt to the

most recent technologies, approaches, and strategies to

reduce the demand on your organization to optimize for


62

endlessly multiplying device types, browser types, and user

behavior patterns.

In addition to those six core functions, an ideal platform should

also provide some form of automation. The digital world is

simply moving too quickly to rely entirely on manual processes,

regardless of how efficient they are.

THINK GLOBALA Silicon Valley based startup wanted to target consumers in

North America—their business model did not expand to other

markets. The company built a technology ecosystem to optimize

performance across the North American continent, confident that

their digital experience optimization strategy was comprehensive

based on their business model. However, they were not aware

that an investor in Qatar had been proactively researching the

company, and was experiencing frustratingly slow load times

when seeking information from the company’s website. The result

of this short-sightedness? A negative digital experience for a key

stakeholder that the company did not even know existed.

When seeking a digital platform, remember to think global.

You may start regionally but, sooner than you expect, you will

want content cached around the world to deliver acceptable

performance to a far-flung audience.


63

What You Learned and Next StepsThe performance challenge is complex, but the solution does

not need to be. It begins with a content audit, knowing how

your content mix impacts performance, and involving cross-

functional teams in the development of a partner ecosystem to

support optimized delivery.

Optimizing the delivery of your online content is not about

displacing existing systems wholesale, but augmenting what

is already in place. As IT spend shifts to the cloud, consider

a platform with a strong content delivery network (CDN)

component. Chapter 5 provides more details on how CDNs

are critical to achieving the best possible performance.


64

CHAPTER 5

Optimizing the Infrastructure

65

CHAPTER 5 : OPT IM IZ ING THE INFRASTRUCTURE

You already know that a

large portion of the network

that delivers your content is

beyond your control.

But the fact remains that by controlling more aspects of the

content delivery path, you can better optimize performance.

The reach of most organizations does not extend past the first

mile, or the point where your servers hand off content to a

third party. Though Internet service providers (ISPs) and mobile

networks claim to provide increasingly fast connection speeds,

a host of variables along every mile of the content delivery

path mean those speeds are not consistent in the real world.

And even if they were, other factors—including availability,

scalability, and user device—would potentially undermine

performance.

The best way to optimize performance across the entire

delivery path is to utilize a CDN. In this chapter, we will discuss

how CDNs optimize performance. Based on the outcome of

your content audit (presented in Chapter 4), you can identify

which optimizations will yield the greatest benefit to your

organization.

66

What is a Content Delivery Network (CDN)?According to Wikipedia, a content delivery network

is a large distributed system of servers deployed in

multiple data centers across the Internet. The goal of a

CDN is to serve content to end-users with high availability

and high performance. CDNs serve a large fraction of

the Internet content today, including web objects (text,

graphics and scripts), downloadable objects (media files,

software, documents), applications (e-commerce, portals),

live streaming media, on-demand streaming media, and

social networks.1

A content delivery network connects two points on the

delivery path: a content provider’s origin in the first mile and

the edge of the networks that end users rely on to access

that content in the last mile. These servers are located in

clusters referred to as points of presence (POPs). POPs must

interconnect with one another across the middle mile. Those

interconnections vary depending on network architecture

and ownership structures, discussed later in this chapter.

1 Wikipedia contributors, “Content delivery network,” Wikipedia, The Free Encyclopedia,

http://en.wikipedia.org/wiki/Content_delivery_network. Accessed December 2013.


67

By extending your infrastructure with a CDN (either self-

hosted or through a service provider), you can provide a

better experience by caching popular content closer to your

audience so that new requests don’t have to travel all the way

back to the origin. In essence, a CDN serves as your proxy to

end users located far from your origin, cutting down on the

distance that content must travel to reach them.

Static Object CachingAll CDNs employ static object caching: storing copies of your

content in edge servers near end users, refreshing it as needed,

and ensuring its availability through replication and backup.

The amount of time that static content can stay in cache on

these edge servers, or its time to live (TTL) value, is high; you can

set policies that dictate when content needs to be invalidated

or refreshed, but for the most part it can be cached near your

end users indefinitely—eliminating the need to cross the first

and middle mile each time it is requested. Therefore, data does

not have to travel from your origin with every request.

If you have a largely static content library (typically image files,

script libraries, and stylesheets) you may not even maintain your

own storage infrastructure, offloading everything to your CDN’s

origin servers in the cloud. This cuts the number of hops required


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to transfer content from your origin to your CDN’s edge servers.

These servers are designed expressly for serving static content,

which reduces processing overhead and increases throughput

for dramatically increased download speed. Static content is

mostly beaconed based on file size, type, and parameters

such as domain names (e.g. static.example.com). This type of

segmentation is not only a good business practice, but also

provides clarity to developers and engineers working on web

applications.

Exchanging Traffic for a Better ExperienceNot only can a CDN manage the storage and distribution

of your content; it also manages the relationships required

to transfer that content across the many connection points

between you and your end user.

Every CDN interoperates with other networks, from mobile

access networks to the ISPs that transfer content between its

POPs. This interoperability is what allows you access to the

entire content delivery path; a CDN maintains the physical

connections with every network that stands between you and

your end user, as well as the relationships required to keep

those connections open.


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Organizations achieve interoperability via a CDN through either

peering or transit. Peering involves voluntarily interconnecting

with separate networks so that traffic can move freely among

them. Peering is usually settlement-free; neither party pays the

other for the traffic exchanged. The mutual benefit for peering

networks is the increased volume of traffic each can handle.

The benefit passed on to you is the ease with which your

content can move across these various networks.

Peering requires physical interconnection of the networks

involved, and an exchange of routing information through the

border gateway protocol (BGP), a routing protocol that enables

the exchange of network path information between networks.

The information includes network addresses and router table

data about how to reach other networks, the number of hops,

and packet loss statistics.

Transit connections are similar to peering arrangements, but

paid for. One party pays another party to increase the reach

of its network (recall that ISPs or mobile networks usually control

Origin Server

DIRECT CONNECTION

DIRECTCONNECTION

USERCONNECTION

Edge Server User Access Network End User Parent Caching Server

ISP


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last mile access networks, or the path between the edge and

end user).

Because a host of physical, technological, economic, and

even political factors affect interoperability, content providers

rely on CDNs to navigate this landscape on an ongoing

basis. Imagine having to maintain physical connections and

individual relationships with each one of the networks involved

in the transmission of your content!

CDN ArchitectureIn addition to moving content among third party networks, a

CDN must move content among its own POPs—for example,

from the server in the POP that ingests content near your origin

to the server in the POP that caches content near your end

user’s access network. CDN architecture, or the positioning of

POPs throughout service areas, varies from provider to provider.

There are two main types of CDN architecture: sparse and

dense.

In a sparse network architecture, POPs are smaller (with fewer

servers) but more numerous. These small concentrations of

servers are typically located at universities and other inexpensive

hosting locations. The servers can be deployed quite far into

last mile access networks, placing your content very close to


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end users. Because servers are located so close to end users,

sparsely architected networks provide the benefit of extended

reach into locations worldwide. However, that may mean

those servers are located farther from your origin, and from

one another. And because there are fewer servers in each POP,

those servers may not be able to hold all of the content that

your CDN is responsible for caching—increasing the likelihood

that a request must travel among POPs before your content

can be located. Content from larger or higher traffic clients may

take precedence, and cache efficiency and offload of origin

traffic can suffer as a result.

In a dense network architecture, larger POPs are clustered

closely around key interconnection points with last mile access

networks. These interconnection points exist over massive

capacity gigabit (over 100GB) ports, which allow seamless,

fast and secure transfer of assets like images, media files

and application centric data. Densely architected network

POPs generally contain more numerous and larger servers

than sparely architected network POPs, and are capable of

handling both small and large objects. They provide higher

cache retention, efficiency, and performance gains to both the

origin infrastructure and the end users; with larger POPs, no

single customer’s traffic is significant enough to utilize the entire

capacity, reducing the need to flush out the cache.


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Your CDN’s architecture can impact your performance, but it is

not the only factor.

Bypassing the Congestion As discussed in the previous section, in addition to connecting

to last mile access networks, a CDN’s servers must connect

to one another. The nature of those connections can impact

performance just as significantly as the location of the POPs

themselves. Network conditions such as lower latency paths,

packet loss and retransmission levels are constantly changing;

routing algorithms therefore have to continually adjust to move

content on the optimal path between POPs. There are two

ways that CDNs can optimize that path.

The first way is by sending content across the access networks

(a method which relies on the public Internet) that connect

POPs to one another. Because public networks are congested,

complex algorithms are required to determine the best way

to route content along them at all times. This approach—

routing content based on algorithms designed to avoid public

Internet congestion—has proven to be successful in solving the

architectural problems of Internet 1.0. But for enterprise class

connectivity and quality of service, some CDNs have developed

more robust interconnection systems.


73

That leads to the second way CDNs optimize connections

between POPs: by bypassing the public Internet completely

and exercising direct control over how the POPs are connected

to one another. In this case, the CDN owns or leases the

direct connections between all of its POPs. Therefore, the CDN

can better respond to any disruptions, such as sudden traffic

spikes, that affect performance. This approach also increases

reliability. Factors such as modified initial congestion windows,

higher persistent connection times and the ability to handle

both compressed and uncompressed content allow these

distributed networks to achieve the performance benefits that

would be impossible at higher traffic volumes across the public

Internet. Moreover, a CDN that exerts control over its own

delivery path does not pay for the transit charges to move

traffic between POPs—a benefit that is passed on to you.

Having a self controlled connection system also allows privately

operated CDNs to provide enhanced service level agreements

(SLAs) as they control the bitstream all the way to the end user

and back to the origin.


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Large and Small Object DeliveryIn Chapter 4 you discovered that websites are made up of

objects large and small. Each requires a different approach

to performance optimization. Small objects, such as thumbnail

images, procedural transactions, Ajax calls, and the database

queries required to set up the delivery of a large file or video

stream, are everywhere in today’s digital environment. The

performance of static small objects can be addressed with

the static object caching strategies discussed above, and with

front end acceleration (discussed in Chapter 6).

When it comes to large static objects such as on demand

video, software updates, or game releases, different strategies

are required. In these cases, last mile bandwidth has a major

impact on performance. If an end user’s ISP connection is slow,

the results are obvious: higher wait times. Your first impulse

may be to optimize performance for maximum bandwidth,

forcing bits across the wire ever so quickly. However, you may

be delivering a huge amount of content that is not actually

ISP LAST MILE

Last Mile Optimizations Middle Mile Optimizations First Mile Optimizations

EDGE SERVER(NEAR USER)

EDGE SERVER(NEAR ORIGIN)

CUSTOMERDATA CENTER

PRIVATEBACKBONE

CONNECTEDOVER LOW RTT TO

CUSTOMER’SDATA CENTER

(ORIGIN)


75

consumed—such as a video file that is abandoned halfway

through viewing because it suddenly buffered. In this case,

you’ve paid to deliver content that nobody consumed.

Unfortunately, many CDNs shy away from delivering large

objects for this reason. Optimizing performance for a large

object consumes more of the CDN’s resources: CPU cycles,

network usage, and bandwidth. It also lowers cache efficiency

in the case of a sparse architecture. The criteria for a “large”

file vary among CDNs; some might classify it as anything larger

than 1MB, and for others that threshold could be 5MB. The

difference doesn’t matter for a few downloads, but at a higher

scale, the difference in the cost of delivery could be exponential

to the CDN. And that added “large object” delivery cost could

be passed on to you.

A CDN capable of large object performance optimization

should be able to achieve intelligent speed: fast enough to

avoid end user perception of latency, but not so fast that an

entire file is delivered even if it is not consumed.

How do you know that the speed your CDN provides is

“intelligent”? Or whether a download was a success or failure?

The answer is analytics. You need details such as point of

abandonment, confirmation of downloads, and performance

against strict service level agreement (SLA) requirements for


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acceptable performance. Specifically, real user monitoring

(RUM), discussed in Chapter 3, gives you insight into how your

objects are performing in the real world.

Whole Site Delivery“Whole site delivery” is a term used to refer to the delivery of both

large and small objects as well as the containers of those files

such as HTML. A CDN may use different architectures to support

objects of different sizes; recall that a densely architected

network consisting of large server concentrations is capable of

handling both large and small objects. Delivering whole sites

is more challenging because they present a heterogeneous

mix of cacheable and non-cacheable content. The main HTML

file could be non-cacheable, but the various components

that make up a page (scripts, images, stylesheets) could be

cacheable. This requires intelligent cache management and

header parsing rules at the edge to differentiate among complex

content needs.


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What You Learned and Next StepsA CDN provides access to global storage, delivery

infrastructure, and optimization techniques that are otherwise

inaccessible to most organizations. Moreover, a CDN

overcomes a major delivery challenge: the inability to access

or control the vast network that transports your content between

you and your end users. Depending on the architecture of the

CDN, content is either optimized to traverse the public Internet

more quickly or routed around it altogether. The ability of any

CDN to control most, if not all, of the end-to-end delivery

network enables better performance for a better end user

experience.

Dynamic content and small objects, however, can be further

optimized with even more extensive techniques. Specialized

CDNs can improve how your dynamic content performs, and

even employ browser specific optimizations on the front end

to speed delivery in the last mile. These optimizations are

discussed in Chapter 6.


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CHAPTER 6

Additional Optimizations

79

CHAPTER 6 : ADD I T IONAL OPT IM IZAT IONS

In the previous chapter, we

discussed how you can

improve performance by

caching static objects on a

content delivery network (CDN).

However, external factors including the rise of dynamic content

and the evolution of browsers mean that static object caching

alone cannot fully address today’s performance issues.

The personalization of the web is driving more dynamic

content. Users increasingly expect sites and apps to remember

who they are, and present them with unique, relevant content

at every turn. Dynamic content acceleration is required to meet

those evolving expectations. At the same time, the number

and type of browsers on the market is changing faster than

any organization can keep pace. Optimizing performance for

these evolving conditions is challenging; best practices du jour

may prove useless or even harmful for tomorrow’s browser. Front

end acceleration (FEA) is the key to improving performance in

this changing environment.

Together, dynamic content acceleration and front end

80

acceleration can yield performance gains above and beyond

traditional CDN services.

The Dynamic ParadoxCaching is a key performance strategy. The general rule: the

closer your end user is to your content, the better. Shorter

distances minimize latency and cut down on unnecessary

network hops that can lead to packet loss and retransmissions.

Caching enables those short distances.

Due to its changing nature, however, most dynamic content

presents problems for caching. It must be repeatedly refreshed

or it risks becoming out of date and inaccurate. (Nobody

wants to view their bank account balance with data from

last week.) The cache-control header values on dynamic

content are typically set to ensure that caching is disabled.

And unlike static content, which can be efficiently cached

in an edge server and counted on not to change for long

periods of time, dynamic content must be uniquely generated

each time it is requested. That means every request for

dynamic content, and in turn the content itself, must travel

all the way across the middle mile and back to the origin;

a network round trip, at minimum.

This round trip occurs not just for the content being rendered


81

on your end user’s screen, but for all of the elements required to

support that content—such as scripts, AJAX calls, and database

queries. And every one of those round trips introduces latency.

HTTPS adds further latency due to the authentication, certificate

handling and digital handshakes required to secure identities.

Even if multiple round trips occur in parallel, most networking

equipment and servers have hard set limitations about how

much content and how large of a payload they can hold until

they start getting congested—limiting the amount of data that

can be transmitted during each round trip. Every packet that

could combine to make up an image, text file, or other web

asset is transmitted through your server’s memory buffer. The

shorter the memory buffer, the smaller the payload and hence

more trips required to transfer your content from one point to

another.

Dynamic content providers, then, face a challenge: how

to achieve the kind of performance gains that static object

caching can yield, given the limitations of dynamic content?

Overcoming the Dynamic ChallengeWhile most CDNs are capable of delivering dynamic content,

few are capable of accelerating that delivery. Specialized

CDNs can help you overcome the dynamic challenge with


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specific optimizations across the middle mile—in essence,

opening up a bottleneck-free world where data can travel

freely between origin and end user.

These specialized CDNs accelerate delivery without affecting

or compromising the availability of your content for true

performance improvements. This is achieved in two ways: route

optimization and TCP acceleration.

Route optimization means selecting a delivery path that

produces the best possible performance. This can involve

optimizing the path your content takes across public networks,

or bypassing those networks altogether on a private network

(see Chapter 5, “ Bypassing the Congestion”). In the same way

that POPs can connect to one another via either publicly or

privately operated networks, origin servers can transfer content

to end users and back using either approach—depending

on the network architecture at work. CDNs that rely on public

networks constantly monitor all connections and control the

flow of your data according to the path of least resistance. In

addition to controlling the flow of your data, privately operated

CDNs control everyone else’s traffic on their network as well.

Transmission control protocol (TCP) acceleration is really a

combination of techniques to improve the performance of

your dynamic content as it travels across the middle mile. Since


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TCP sets limitations on how your content can move across the

Internet, specialized techniques are required to either respond

to or overcome those limitations. The following are the key TCP

acceleration techniques applied by CDNs.

• Persistent connections: Every request for content introduces

more latency. Persistent connections mean that once a

connection is opened, it is kept alive for an extended

period of time. Data moves repeatedly across that same

connection, reducing the total number of connections (and

thus congestion) across the network. A specialized CDN

should be able to automate the establishment of persistent

connections based on a number of changing factors

including your end user’s device and browser type.

• Congestion window scaling: TCP window size is determined

based on the amount of data that can be buffered during

a connection. Rather than coding TCP window sizes into

your content, a CDN offers congestion window scaling to

maximize throughput on the fly, during the connection, to

adapt to changing conditions.

• TCP buffer management: If a data packet is dropped

because of buffering, the receiving side cannot accept any

data and a new round trip must be initiated to re-request

the packet, introducing additional latency and wasting

valuable resources. Buffer management means applying


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algorithms to select which packet is discarded in the event

of buffering, based on the potential performance impact.

Rather than hard code those decisions into your content, a

CDN can make them on a case by case basis to optimize

your performance.

• Retransmission timeouts: Retransmissions occur when a

receiver does not acknowledge data in the time frame

established by the predetermined retransmission timer.

However, if too many retransmissions occur, it results in a

retransmission timeout; the sender must wait for the timeout

period to complete before sending any further data, and the

retransmission time for the next TCP segment may be reduced.

On a congested link, retransmission timeouts can occur by

the million. To remedy this issue, your CDN should be able to

retransmit data before the timeout even occurs, and set the

retransmission time for the next TCP segment accordingly.

Between route optimization and TCP acceleration, dynamic

content acceleration opens a bottleneck free tunnel between

an edge server and the origin, accelerating data transfers and

improving availability.


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Front End AccelerationWhile dynamic content acceleration optimizes the manner in

which content travels to end users, front end acceleration (FEA)

improves performance by transforming the content itself. You

know that performance is about more than speed; You now

have a full list of KPIs (discussed in Chapter 3). In the case of FEA,

performance is about lowering perceived wait times for your

end user in order to speed “time to interaction,” or the point

that the user can start interacting with your content.

In many websites and web applications, a user is unable to

click, browse, search, or transact until all of the elements and

components of that site or app have loaded. On its own, your

site or app might not be able to determine which portion of

your content is visible without scrolling; for example, a browser

does not know to load the “buy now” button before all scripts

have run. Tasks are executed in the order they are coded, not

necessarily in the order that the end user cares about them.

And even if your development team is already optimizing

code to load content based on user preferences for better

performance, the number and evolution of browsers on the

market makes that a self defeating exercise.

FEA analyzes and actually alters your code to load content


86

more intelligently, based on user expectations. This is done

with a variety of techniques that can be applied to your

content as well as any third party content on your site (such

as advertisements). These techniques fall into two categories:

browser optimizations, and script optimizations.

By placing the responsibility of staying ahead of the most

recent trends and changes in the browser market on your

CDN, you free your development team to focus on business-

building tasks like developing new features and functionalities.

A mobile banking app developer, for instance, should be

able to improve product usability without worrying whether

downloading more client-side scripts will reduce application

performance or introduce more latency.

Understanding Browser PerformanceBrowsers can both add to and detract from the end user

experience. The good news: they are constantly evolving, and

improving workarounds to bottlenecks. The bad news: the

improvement can introduce even more, new bottlenecks. The

rapid proliferation of browsers and non standardization leaves

350 100100

MSMSMSMS

250


87

web development teams scrambling to keep up with every

advance in every browser from every vendor in an effort to

ensure the best website performance.

As stated previously in this chapter, self performed optimizations

are common—but can actually work against you. Shaving

milliseconds off load times for the latest version of a browser

may add milliseconds on the next release. For instance,

efforts to boost browser parallelism now enable six or more

connections. But unconditionally implementing this parallelism

can run into client CPU and home router limitations. (In most

cases, two connections still yield a benefit but four connections

push the point of diminishing returns.) Adding more parallel

connections to the browser that open to the origin does not

necessarily guarantee a parallel download of content. And

many origin servers are misconfigured to prevent persistent

connections, thus making it incredibly difficult to download

content that is dynamic.

Mobile browsers have even more latency problems, and higher

network and hardware dependency. Caching content closer

to end users can reduce round trip time from 100 milliseconds

around the country to two or four milliseconds within the state.

But that solves only a part of the problem; the segmentation

of web content and complex nature of today’s websites and

applications include hundreds of individual file and page


88

elements that get downloaded separately. When scaled up

for these hundreds of objects, a few milliseconds of latency can

lead to major delays.

CDNs can improve browser performance by optimizing the

number of user browser connections to download additional

resources during page loading for faster page rendering.

Furthermore, your CDN should be capable of compressing

content to free up bandwidth and storage; compression

generally reduces the file size by about 70%.1 Anything text

based can be compressed including XML and JSON; most

websites zip their HTML documents as well. Compression reduces

response times by reducing the size of the HTTP response. It is

also worthwhile to compress scripts and stylesheets, but many

content providers miss this opportunity.

Currently, the Gzip approach is the most popular and

effective compression method. Approximately 90% of

today’s Internet traffic travels through browsers that claim to

support the Gzip approach.2 The Gzip approach should

not be applied to image and PDF files because they are

already compressed. Trying to apply it in these cases not only

wastes CPU, but can also potentially increase file sizes. Still,

compressing as many file types as possible is a simple way

1 Steve Souders, “Rule 4: Gzip components,” in High Performance Web Sites:

Essential Knowledge for Front-End Engineers (O’Reilly Media, Inc., 2007), 31.

2 Souders, “Rule 4: Gzip components,” 34.


89

to reduce page weight and accelerate the user experience.3

Though they cannot be compressed, images can be combined

into larger payloads (such as single compressed packages)

that can be delivered that much more efficiently to your

end user.

Script OptimizationsThe way web pages are loaded greatly affects the user’s

perception of page performance. Ideally, the most important

content appears first, or to borrow a term from the newspaper

publishing industry, above the fold (in the top half of the display,

before the user navigates downward). Code, however, is

sometimes written to load scripts first, even though many of those

scripts will not be needed right away. Specifically with respect to

the JavaScript programming language, your page may behave

differently when some script loading is deferred.4 For example, if

the script is written to expect certain user actions, such as onclick

or onkeypress, these actions will not be triggered until the page

is rendered completely.

Deferring scripts and giving prioritized loading to other

content elements can dramatically improve the end user’s

3 Yahoo! Inc., “Best Practices for Speeding Up Your Web Site,” http://developer.yahoo.com/

performance/rules.html. Accessed December 2013.

4 Google Inc. Google Developers, “Defer JavaScript,” last modified May 23, 2013,

https://developers.google.com/speed/pagespeed/service/DeferJavaScript. Accessed

December 2013.


90

perception of your site’s rendering speed (more critical than the

rendering speed itself; recall your KPIs). Critical elements can

be programmed to appear above the fold first and fast while

compensating for any actions that have been delayed. It can

also spare valuable memory and processing on the back end.

It makes sense for your developers to work with CDN

engineers to plan a transparent integration of CDN services in

advance. If executed correctly, intelligent scripting techniques

allow should pages and apps to retain their original look

and feel. The goal is to create an experience so seamless

that the entire delivery path is invisible to the end user, who

experiences near instantaneous response to each request.


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A WORD ON MOBILEGiven the projected penetration of mobile browsing on the

Internet, mobile access networks are poised to dominate the last

mile of the delivery path. Mobile should be a consideration in any

effort to optimize online performance.

For now, redirects to mobile websites are the only way to keep

response time under 100 milliseconds, the point at which users

perceive delay. Yet on many sites, the mobile device has to follow

multiple redirects just to load the desired page. Keeping web

server configuration files as short as possible through redirects

may have some merit, but in the case of mobile, it may not be

worth the price users have to pay on every visit.

Device detection in general is easily accomplished by setting

proper headers. Once detected, the system loads content

optimized for that particular device down to the make, model,

and release version. For example, an iPhone® device receives

a smaller version of the content compared to Microsoft®

Internet Explorer® 11, which requires the full resolution version

of a piece of content. Device detection is an area where a

CDN can be particularly helpful. While most organizations

optimize their websites for a browser, a good CDN will

optimize for almost every browser, desktop and mobile device.


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What You Learned and Next StepsTraditional CDN services (static object caching) are not

enough to improve performance in today’s digital landscape.

Increasingly dynamic content requires a new approach, one

that involves improving performance across the middle mile

of the delivery path. What’s more, a quickly evolving browser

market requires optimizations on the front end to stay on top

of the latest standards.

How do you know if these optimizations are working to

support your KPIs? After all, the network where they are

executed is invisible to you. Your CDN should provide

detailed analytics about how your content performs, from

the end user perspective—commonly in the form of real user

monitoring (RUM). Based on these analytics, you can ensure

that optimizations are performed at the right intervals and with

minimal overhead. Or, set new policies and adjust optimizations

to improve performance even further.

Combined with static object caching, dynamic content

acceleration and front end acceleration are critical parts of

any technology ecosystem designed to optimize content

delivery. So now what do you do? That is what we will take up

in Chapter 7.


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CHAPTER 7

Making the Case: Your Optimization Checklist

94

CHAPTER 7: MAKING THE CASE: YOUR OPT IMIZAT ION CHECKL IST

By now you know what it

takes to successfully deliver

your websites and web

applications.

With full insight into the networks and technologies that impact

your online performance, you are prepared to play the role of

performance champion in your organization.

There is just one more critical aspect to the successful execution

of your digital experience optimization strategy: support from

executive leadership. In this chapter you will learn how to

create a compelling case for performance in business terms.

SummaryLet’s review what you have learned in this book so far.

• Performance matters. The business cost of poor

performance is proven and measurable; 1% of lost sales

for every second of delay by one measure,1 and 20%

decrease in traffic and revenues for every half-second

1 Amazon.com, Inc., “Make Data Useful,” (presentation, 2009), https://sites.google.com/site/

glinden/Home/StanfordDataMining.2006-11-28.ppt?attredirects=0. Accessed December 2013.

95

delay by another.2 At the same time, user expectations are

high; after 100 milliseconds, you lose their attention.3

• Your organization’s digital presence is the key to its

competitive edge. Achieving high performance (i.e. making

your content available when a user requests it) is a complex

challenge. In-house optimizations are a valuable start, but

a comprehensive strategy can improve performance to a

greater extent than many organizations realize is possible.

• To better deliver your digital content, it is important to

understand the network where it resides. The first, middle,

and last miles of the content delivery path (all of the points

between you and your end users) are each impacted by

different bottlenecks. Your access to that content delivery

path is limited, and you have limited control over the

bottlenecks that occur there.

• When it comes to improving performance, consider elements

in addition to just raw network speed. As you establish a

performance baseline to improve against, factor in KPIs in the

areas of speed, availability, scalability, multi device support,

and end user experience. Real user monitoring (RUM) will give

you the most accurate sense of how well you are performing

in the real world, and how you can improve.

2 Greg Linden, “Marissa Mayer at Web 2.0,” November 9, 2006, http://glinden.blogspot.com/2006/11/marissa-mayer-at-web-20.html. Accessed December 2013

3 Ilya Grigorik, “Building Faster Mobile Websites,” (presentation, San Francisco HTML5 Meetup, March 21, 2013), https://plus.google.com/u/0/+IlyaGrigorik/posts/WZeETYCcm1X. Accessed December 2013.


96

• Improving performance requires a partner ecosystem.

Building that ecosystem begins with a content audit to

identify the characteristics most important to performance.

Internal stakeholders, especially marketing, can then

productively discuss optimization requirements. Together

you can impact some aspects of performance; others

require a CDN partner to deliver your content for the best

possible performance.

• In terms of performance, a content delivery network (CDN)

is the cornerstone of your partner ecosystem. By caching

your static content near end users, a CDN can optimize

performance across the entire delivery path on your behalf,

providing access and control otherwise unavailable to you.

Depending on the architecture of your CDN, you may be

able to bypass the congested public Internet altogether

on a private network.

• Traditional CDN services alone will not adequately

address today’s performance issues. The explosion of

dynamic content (which cannot be cached like static

content) and changing browser requirements (which

require ongoing specialized knowledge to optimize

for) mean that you cannot just cache static content and

walk away. Route optimization and TCP acceleration

across the middle mile, as well as front end acceleration


97

in the browser, complete the picture when it comes to

the technology required to improve performance

for today’s web.

The time has come for every organization to put performance

front and center. Here are the steps that will assist you in

developing a performance proposal that can garner broad

support with stakeholders.

Step 1: Benchmark YourselfChapter 3 of this book provides you with a list of potential KPIs

you will use to establish a performance baseline. These KPIs

will be directly related to the kind of content you are delivering

(we explained how to perform a content audit in Chapter 4).

It is important to review the results of both your KPI benchmark

exercise and content audit with all performance stakeholders

in your organization to confirm that they are aligned with the

goals of your business.

Knowing how you perform against your competitors is

also important in making the case for performance to your

executive leadership. The tools provided in Chapter 3 (“How

Effective is Your Visitor Experience?”) provide information to help

you analyze the effectiveness of the digital experiences you

create. Many of them can do the same for your competition.


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Whenever possible, the tests you run on your own web content

should be run on your competitors’ as well.

In fact, some tools exist to help you benchmark your performance

against the standards of your industry as a whole. Compuware

APM’s® benchmark tool4 and Alexa Internet, Inc.’s Top Sites list5

are both valuable resources.

Step 2: Quantify ValueExecutive management may not be interested in knowing that

you shaved milliseconds off load times or deferred script loads.

You must build the case for performance in terms that are

important to them, and that is not likely to be technical speeds

and feeds.

The key to securing management’s investment in performance

is to quantify its financial value. It may be a lower total cost

of ownership (TCO) or higher return on investment (ROI). It

may be increased revenues or decreased capital expenses.

Whatever the metric, there is a financial impact attached to

your performance. And above all, management will want to

know what that financial impact is.

The statistics presented in this book regarding the general

4 Compuware APM, “Compuware APM Benchmarks,” http://www.compuware.com/en_us/

application-performance-management/Benchmarks/view-benchmarks.html. Accessed

December 2013.

5 Alexa Internet, Inc., “Top Site,” http://www.alexa.com/topsites/category. Accessed

December 2013.


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importance and value of performance are a good way to

begin the conversation, but to truly win support from executive

management you must contextualize the value of performance

for your business specifically. You will also want to present that

value in the context of senior management’s own KPIs and the

overall strategic goals of your organization.

Step 3: Build Your Partner EcosystemOnce you have established a baseline and agreed on

performance goals with key stakeholders, you will need an

ecosystem built to optimize content delivery. This should be

done seamlessly, automating workflows at every opportunity

for higher return on investment. A CDN is a critical element of

this partner ecosystem and is required to significantly improve

web performance. Pay attention to these qualities as you

consider potential partners:

• Integration

• Manageability

• High performance

• Resiliency

• Elasticity

• Future proofing


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Step 4: Schedule System ChecksYou’ve heard it before: improving performance is not a

one-time engagement. Though aspects of performance

optimization can be automated, the improvements yielded by

those optimizations need to be continually assessed and re-

evaluated. (For example, content will change and the size of

your content library may fluctuate.)

Day to day, you will rely on RUM to measure users’ experience

in the real world, while live reporting and analytics should be

made available to you by your CDN on a geographical basis

in real time or near real time. It is also best practice to conduct

a high-level performance review against your KPIs and re-audit

your content on a monthly basis, to monitor changes or trends

worthy of your attention.

But the performance stakeholders in your organization will

want to know how you are progressing against the objectives

laid out in your initial proposal. You will want to show results

that speak to revenue, savings, business value, customer

satisfaction, and other matters uniquely important to each

stakeholder, particularly executive management. In addition to

tracking the KPIs, remember to track your progress against the

initial goals.


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You’ve Got This!Your organization has invested a tremendous amount of work

in developing a strong digital presence. But unless it is delivered

successfully—unless content performs in a way that allows end

users to locate and interact with it in the way they want—

all is lost.

As the person responsible for optimizing the delivery of your

online content, you face significant challenges across the entire

path that connects you to your end users. First, middle, and last

mile bottlenecks are not only numerous, but often out of your

reach and direct control.

Fortunately, there is a wealth of tools at your disposal to overcome

these challenges. An architected and managed approach to

performance optimization yields significant performance gains

along the entire delivery path. It maximizes internal resources.

It future proofs your business. And most importantly, it creates a

superior digital experience for your end users. They won’t have

to wait for your valuable content!

When it comes to performance, every millisecond matters.

Make them count. Start now.


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About Limelight NetworksLimelight Networks, a global leader in digital content delivery,

empowers customers to better engage digital audiences by

enabling them to manage and deliver digital content on any

device, anywhere in the world. The company’s award winning

Limelight Orchestrate™ platform includes an integrated

suite of content delivery technology and services that helps

organizations deliver exceptional multi-screen experiences,

improve brand awareness, drive revenue, and enhance

customer relationships — all while reducing costs. For more

information, please visit www.limelight.com and follow us on

Twitter at @LLNW.

ABOUT L IMEL IGHT NETWORKS

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