akamai cloud computing perspective
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White Paper
Akamai and Cloud ComputingA Perspective from the Edge of the Cloudby Tom Leighton, co-Founder and Chief Scientist, Akamai Technologies
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INTRODUCTION. 1
UNDERSTANDING.THE.CLOUD. 1
. The.Cloud.Computing.Framework 1
Virtualization 2
Infrastructure-as-a-Service 2
Platform-as-a-Service 2
Software-as-a-Service 2
CloudOptimizationServices 2
. Public.Clouds.and.Private.Clouds. 3
ANATOMY.OF.A.CLOUD . 3
. The.Middle.Mile.Conundrum 3
PeeringPointProblems 4
RoutingVulnerabilities 4 InefficientCommunicationsProtocols 4
NetworkOutages 5
. Cloud.Computing.Architectures. 5
CentralizedDatacentersNewOpportunity,OldApproach 5
HighlyDistributedNetworksGettingClosetoEndUsers 5
AKAMAIS.EDGEPLATFORM:.OPTIMIZING.THE.CLOUD. 6
. Accelerating.Cloud.Computing.Applications 6
RouteOptimization 6
CommunicationsOptimization 6
ApplicationOptimization 7
. Distributing.Application.Components.to.the.Edge 7
. Securing.Cloud.Applications.and.Platforms 7
Ensuring.Site.and.Application.Availability 7
CONCLUSION 8
ABOUT.AKAMAI 8
Table of Contents
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IntroductionAs one of the hottest concepts in IT today, cloud computing
proposes to transform the way IT is consumed and managed,
with promises of improved cost efciencies, accelerated innova-
tion, faster time-to-market, and the ability to scale applications
on demand. While the market is abundant with hype and
confusion, the underlying potential is real and is beginning
to be realized.
In particular, SaaS applications and public cloud platforms have
already gained traction with small and startup businesses. These
offerings enable companies to gain fast, easy, low-cost access
to systems that would otherwise cost them millions of dollars
to build. At the same time, cloud computing has drawn the
cautious but serious interest of larger enterprises in search of its
benets of efciency and exibility.
However, as companies begin to implement cloud solutions, the
reality of the cloud itself comes to bear. Most cloud computing
services are accessed over the Internet, and thus fundamentallyrely on an inherently unpredictable and insecure medium. In
order for companies to realize the potential of cloud comput-
ing, they will need to overcome the performance, reliability, and
scalability challenges the Internet presents.
This whitepaper provides a framework for understanding
the cloud computing marketplace by exploring its enabling
technologies and current offerings, as well as the challenges it
faces given its reliance on the Internet. With an understanding
of these challenges, we will examine Akamais unique role as
provider of the critical optimization services that will help cloud
computing fulll its promise to deliver efcient, on-demand,
business-critical infrastructure for the enterprise.
Understanding the CloudSimply dened, cloud computing refers to computational re-
sources (computing) made accessible as scalable, on-demand
services over a network (the cloud). And yet, cloud comput-
ing is far from simple. It embraces a conuence of concepts
virtualization, service-orientation, elasticity, multi-tenancy,
and pay-as-you-go manifesting as a broad range of cloud
services, technologies, and approaches in todays marketplace.
To facilitate our discussion of this diverse marketplace, we rst
lay out a framework that gives structure to the different offer-
ings in the cloud computing space. We will also explore
the role of public and private clouds in the marketplace.
The Cloud Computing Framework
Our cloud computing framework has ve key components.
The rst, virtualization technology, can be thought of as an
underpinning of cloud computing. By abstracting software from
its underlying hardware, virtualization lays the foundation for
enabling pooled, shareable, just-in-time infrastructure. On top
of this technology base, cloud computings principal offerings
can be categorized into three main groups: Infrastructure-as-
a-Service, Platform-as-a-Service, and Software-as-a-Service.
Cloud optimization is the nal, critical piece of the framework
encompassing the solutions that enable cloud computing
to scale and to deliver the levels of performance and reliability
required for it to become part of a businesss core infrastruc-
ture. We will now look at each of these framework components
in more detail.
Cloud Computing Framework
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Virtualization
Virtualization is the technology that gave birth to the current
cloud computing frenzy and is arguably the trend having the
highest impact on the evolution of infrastructure. By abstracting
server software from the underlying hardware, server virtualiza-
tion improves the efciency and availability of resources and ap-
plications running on that server. It is generally acknowledgedthat roughly 80% to 90% of enterprise computing capacity is
unused at any given time. Virtualization enables these once-idle
CPU cycles to be used.
Taking the concept of server virtualization to the cloud means
extending it going beyond the more efcient use of a single
physical machine or cluster to the aggregation of comput-
ing resources across multiple data centers, applications, and
tenants, and allowing each to scale up or down on demand.
This enables cloud providers to efciently manage and offer
on-demand storage, server, and software resources for many
different customers simultaneously.
Signicant cloud virtualization technologies include:
Microsoft (HyperV)
VMWare (ESX, as well as multiple related VMWare offerings)
Xen (open source hypervisor, used by Amazon EC2 and in
Citrix XenServer)
Infrastructure-as-a-Service
Infrastructure-as-a-Service (IaaS) describes the category of cloud
computing offerings that make basic computational resources
such as storage, disk space, and servers available as
on-demand services. Rather than using physical machines, IaaS
customers get access to virtual servers on which they deploytheir own software, generally from the operating system on up.
IaaS offers cost savings and risk reduction by eliminating the
substantial capital expenditures required when deploying infra-
structure or large-scale applications in-house. Cloud providers
generally offer a pay-as-you-go business model that allows
companies to scale up and down in response to real-time busi-
ness needs, rather than having to pay up front for infrastruc-
ture that may or may not get used, or having to overprovision
resources to address occasional peaks in demand. To date, IaaS
has seen heaviest adoption among small to mid-sized ISVs and
businesses that dont have the resources or economies of scale
to build out large IT infrastructures.
Examples of cloud IaaS offerings include:
Akamai (NetStorage and CDN services)
Amazon (Elastic Compute Cloud/EC2 and Simple Storage
Service/S3)
GoGrid (Cloud Servers and Cloud Storage)
Joyent (Accelerator)
Platform-as-a-Service
A fast-growing category of cloud computing offerings is
Platform-as-a-Service (PaaS), which consists of offerings that
enable easy development and deployment of scalable Web
applications without the need to invest in or manage any
underlying infrastructure. By providing higher-level services than
IaaS, such as an application framework and development tools,PaaS generally provides the quickest way to build and deploy
applications, with the trade off being less exibility and poten-
tially greater vendor lock-in than with IaaS.
The PaaS landscape is broad and includes vendors such as:
Akamai (EdgeComputing)
Elastra and RightScale (platform environments for
Amazons EC2 infrastructure)
Google (App Engine)
Microsoft (Azure)
Oracle (SaaS Platform)
Software-as-a-Service
The best enterprise-ready examples of cloud computing are
in the Software-as-a-Service (SaaS) category, where complete
end-user applications are deployed, managed, and delivered
over the Web. SaaS continues the cloud paradigm of low-cost,
off-premise systems and on-demand, pay-per-use models, while
further eliminating development costs and lag time. This gives
organizations the agility to bring services to market quickly and
frees them from dependence on internal IT cycles. The speed
and ease with which SaaS applications are purchased and con-
sumed has made this category of cloud computing offerings the
most widely-adopted today.
Important cloud SaaS vendors and services include:
Adobe Web Connect, Cisco WebEx, Google Mail, Hotmail,
Yahoo! Mail (communications applications)
Demandware (e-Commerce)
NetSuite (Accounting, ERP, CRM, and e-Commerce)
SAP Business ByDesign (HR, Finance and other ERP applica-
tions)
Workday (HR, Finance, and Payroll)
Cloud Optimization Services
The nal piece of the cloud computing framework, cloud opti-
mization services provide performance, scale and reliability for
all of the previously-described components of cloud computing.
They enable cloud offerings to operate across an unpredict-
able and unreliable Internet while delivering the robust levels of
service required by enterprises.
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The value of cloud optimization services can be understood as
a direct function of application adoption, speed, uptime and
security. Without optimization services, cloud offerings are at
the mercy of the Internet and its many bottlenecks and the
resulting poor performance has a direct impact on the bot-
tom line. For example, a site leveraging IaaS components that
fail to scale for a ash crowd will lose customers and revenue.
Likewise, a SaaS application that is slow or unresponsive willsuffer from poor adoption. Thus, cloud optimization is essential
for cloud computing services to be able to meet enterprise com-
puting requirements.
In theAnatomy o a Cloudsection below, we will take a closer
look at the root causes of the Internets bottlenecks. This will lay
the foundation for understanding why Akamai, with its highly-
distributed network of servers, is uniquely positioned to provide
the critical optimization services that can transform the Internet
into a high-performance platform for the successful delivery of
cloud computing services.
Public Clouds and Private CloudsMost of the early spend and traction for cloud computing
(including, for example, the IaaS, PaaS, and SaaS vendors
mentioned above) have been focused onpublic cloudservices
those that are accessed over the public Internet. Public cloud
offerings embody the economies of scale and the exible, pay-
as-you go benets that have driven the cloud computing hype.
More recently, the concept ofprivate clouds (or internal clouds)
has emerged as a way for enterprises to achieve some of the
efciencies of cloud computing with an infrastructure internal
to their organization, thus increasing perceived security and
control. By implementing cloud computing technologies behind
their rewall, enterprise IT teams can enable pooling and shar-ing of compute resources across different applications, depart-
ments, or business units within their company.
Private clouds require signicant up-front development costs,
on-going maintenance, and internal expertise, and therefore
provide a much different benet prole compared to public
clouds. Private clouds are most attractive to enterprises that
are large enough to achieve economies of scale in-house and
where the ability to maintain internal control over data, ap-
plications, and infrastructure is paramount. Even private clouds,
however, often have at least partial dependence on the public
Internet, as these large enterprises must support workers in
dispersed geographic locations as well as telecommuting ormobile employees.
In reality, most enterprise cloud infrastructures will be hybrid
in nature where even a single application can run across a
combination of public, private, and non-cloud environments.
For example, a company may run highly-sensitive components
strictly on-premise (in a non-cloud environment) while leverag-
ing public cloud offerings for other application components to
achieve cost-effective scalability.
So regardless of the path that enterprise adoption of cloud
computing takes, the public cloud that is, the Internet wil
play a vital role. And the taming of that cloud with its inher-
ent performance, security, and reliability challenges is anelement essential to cloud computings success.
Anatomy of a CloudWhen wrapped up in the hype of cloud computing, it is easy
to forget the reality that cloud computings reliance on the
Internet is a double-edged sword. On one hand, the Internets
broad reach helps enable the cost-effective, global, on-demand
accessibility that makes cloud computing so attractive. On
the other hand, the naked Internet is an inherently unreliable
platform fraught with inefciencies that adversely impact
the performance, reliability, and scalability of applications and
services running on top of it.
We now take a closer look at the causes of these bottlenecks
and the impact that different cloud computing architectures
can have in addressing them.1
The Middle Mile Conundrum
The infrastructure that supports any Web-based application,
including cloud computing services, can be split into three
basic parts: the frst mile, or origin infrastructure; the last mile,
meaning the end users connectivity to the Internet; and the
middle mile, or the paths over which data travels back and forth
across the Internet, between origin server and end user. Each of
these components contributes in different ways to performance
and reliability problems for Web-based applications and services
A decade ago, the last mile of the Internet was likely to be
one of the biggest bottlenecks, as end users struggled with
slow dial-up modems. Today, however, high levels of global
broadband penetration over 400 million subscribers
worldwide, as well as continually increasing broadband speeds,
have not only made the last-mile bottleneck history, they have
also increased pressure on the rest of the Internet infrastructure
to keep pace.2
First mile bottlenecks are fairly well-understood and, more
importantly, fall within the origin providers control. Perhapsthe biggest rst mile challenge lies in the ability to scale the
origin infrastructure to meet variable levels of demand. Not only
is it difcult to accurately predict and provision for demand,
but it is costly to have to overprovision for occasional peaks
in demand resulting in infrastructure that is underutilized
most of the time. Cloud computing promises to alleviate this
to some degree, as cloud providers can pool resources among
multiple customers so that variability in demand is smoothed
out somewhat across the group.
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This leaves the middle mile the mass of infrastructure
that comprises the Internets core. Indeed, the term middle
mile is itself a misnomer in that it refers to a heterogeneous
infrastructure that is owned by many competing entities and
typically spans hundreds or thousands of miles. While we often
refer to the Internet as a single entity, it is actually composed
of 13,000 different networks, joined in fragile co-opetition,
each providing access to some small subset of end users. Thelargest single network accounts for only about 8% of end user
access trafc, and per-network share of access trafc drops
off dramatically from there to be spread out over a very long
tail. This means the performance of any centrally-hosted Web
application including cloud computing applications is
inextricably tied to the performance of the Internet as a whole
including its thousands of disparate networks and the tens
of thousands of connection points between them.
Given this complex and fragile web, there are many
opportunities for things to go wrong. We now take a
closer look at four of the key causes of Internet middle-mile
performance problems.
Peering Point Problems
Internet capacity has evolved over the years, shaped by market
economics. Money ows into the networks from the rst and
last miles, as companies pay for hosting and end users pay for
access. First- and last-mile capacity has grown 20- and 50-fold,
respectively, over the past ve to 10 years. On the other hand,
the Internets middle mile made up of the peering and transit
points where networks trade trafc is literally a no mans
land. Here, economically, there is very little incentive to build
out capacity. If anything, networks want to minimize trafc
coming into their networks that they dont get paid for.
As a result, peering points are often overburdened, causing
packet loss and service degradation, and, in turn, slow and
uneven performance for cloud-based applications. The further
away a cloud service is from its end customers, the greater the
impact of Internet congestion. For enterprises that are accus-
tomed to LAN-based speeds, this performance bottleneck can
seriously affect the adoption of cloud computing.
The fragile economic model of peering can have even more
serious consequences. For example, major network provider Co-
gent de-peered for several days with Telia and Sprint in March
and October 2008, respectively, over peering-related business
disputes. In both cases, the de-peering partitioned the Internet.This means, for example, that users on the Sprint network,
as well as any other networks single-homed to Sprint, would
not have been able to reach any cloud services or applications
hosted on Cogent (or any network single-homed to Cogent).
According to the Internet analyst rm Renesys, the Cogent-
Sprint de-peering left more than 3500 networks with signi-
cantly impaired connectivity.3
Routing Vulnerabilities
BGP, or Border Gateway Protocol, is the Internets inter-network
routing algorithm the protocol that determines how data
packets travel from one network to another within the cloud.
While BGP is simple and scalable, it was designed neither for
performance or efciency and thus has a number of well-docu-
mented limitations.
For example, BGP is vulnerable to foul play as well as human er-
ror. This was widely evidenced in February 2008 when Pakistan
accidentally caused a global YouTube blackout by broadcasting
a more specic BGP route for YouTube.4
Although BGP does respond to major changes in network con-
gestion, it is not as good at making ne distinctions between
the trafc on multiple routes and it reacts more slowly to
changes in trafc levels.
Thus, while BGP may work reasonably well when only best-
efforts delivery is needed, requirements for enterprise cloud
computing are typically far more stringent, demanding greaterperformance and reliability than BGP alone can deliver.
Inefcient Communications Protocols
Architected for reliability rather than efciency, TCP or Trans-
mission Control Protocol the Internets primary communica-
tions protocol is another source of drag on the Internet.
TCP requires multiple round-trips (between the two commu-
nicating parties) to set up and tear down connections, uses a
conservative initial rate of data exchange, and recovers slowly
from packet loss. This overhead is especially detrimental to the
performance of SaaS- and PaaS-based enterprise applications,
as these applications tend to be chatty, requiring many small,
quick, back and forth communications.
Another surprising effect of the way TCP works is that long
distances between communicating parties can lead to very low
throughputs and very high download times an effect that
becomes increasingly pronounced as le sizes grow larger. This
is because TCP allows only small amounts of data to be sent at
a time before pausing and waiting for acknowledgments from
the receiving end. Thus, even a very small network latency (the
time it takes a single data packet to travel across the network)
can translate into a huge delay for large les. As latency is
directly tied to distance (i.e., it is lower-bounded by the speed
of light), we see that for large data transfers such as media les
end user download times are limited not by network capacity
or last mile bandwidth, but by the distance between server and
end user. This is a critical issue for those considering IaaS stor-
age solutions, among others.
Network congestion further complicates the problem, since TCP
requires transmitters to back off and send even less data before
waiting for acknowledgment if packet loss is detected. This
means that the interplay between different Internet bottlenecks
can further exacerbate an already difcult situation.
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Network Outages
As enterprises shift their computing from on-premises systems
to the cloud, ensuring the reliability of their platform suddenly
becomes far more complex. Internet failures can happen on
several different levels from a single router malfunction
to a data center blackout to an entire network going ofine.
Unfortunately, large scale outages happen more often than onemight expect. With causes that vary from trans-oceanic cable
cuts and power outages to DDoS attacks and natural disasters,
wide-scale network problems can severely disrupt communica-
tions across large regions of the globe.
Over the last year, for example, undersea cable cuts severely
impacted communications in Southeast Asia and the Middle
East on two different occasions. According to TeleGeography,
the rst incident, in January 2008, reduced bandwidth con-
nectivity between Europe and the Middle East by 75%.5 The
second incident, in December 2008, caused extensive outages
for large numbers of networks in Egypt and India, according to
Renesys.
6
In both cases the disruptions lasted for multiple days.
Cloud Computing Architectures
The middle mile bottlenecks described above create an
environment that is difcult to rely on for business-critical
transactions. However, by avoiding the middle mile as much
as possible, applications and services can be delivered over
the Internet with much greater security, speed, and reliability.
Thus, as we begin to see a shift in focus from the hype around
cloud computings potential benets to the reality of imple-
menting and using cloud-based solutions, the questions that
have been conveniently abstracted away thus far (e.g., Where
exactly are these cloud services running? What do these
cloud architectures look like?), now become critically relevant.
Despite the broad variety in cloud computing offerings, their
underlying deployment infrastructures can be categorized into
two basic architectures centralized versus highly-distributed.
These two network architectures have existed long before
the cloud computing phenomenon; they are in fact the same
architectures that underlie all Web-based infrastructures. So
while cloud computing may revolutionize the way infrastructure
and applications are consumed, its underlying deployment
infrastructure is nothing new.
Centralized Datacenters New Opportunity,
Old Approach
As with traditionally-architected Web sites, SaaS, PaaS and IaaS
providers typically host their applications and services in a single
location or a small number of datacenters.
For example, Amazon hosts EC2 in just three US datacenters
and a single European datacenter and private clouds, whether
collocated or on-premises, often run from a single location.
This approach is adequate when application users are very close
to the application host location. For example, a single location
can be adequate for a private cloud serving an on-premises
group of employees.
However, for applications with distributed users or highly-
variable demand, the centralized datacenter approach is
insufcient, as it results in an end user experience that suffers
at the mercy of the Internets middle mile. This means network
outages, peering point congestion, routing inefciencies, and
other middle mile bottlenecks will frequently cause applicationperformance and reliability to fall short of expectations.
Highly Distributed Networks Getting Close to End Users
By locating cloud computing infrastructure in a highly-distributed
manner, it is possible to overcome the challenges posed by the
Internets middle mile. A highly-distributed architecture where
servers are located at the edge of the Internet, close to end users
(e.g., directly within the end users ISP, in the end users city)
avoids the middle mile bottlenecks weve mentioned, enabling
the delivery of LAN-like responsiveness for applications running
over the global Internet.
Akamai is unique in taking this approach. While a number
of other large cloud providers including content delivery
networks do run multi-datacenter operations, these are
fundamentally different from the highly-distributed network
Akamai uses. With a centralized or multi-datacenter infras-
tructure, the cloud providers servers are still far away from
most users and must still deliver content from the wrong side
of the middle mile bottlenecks.
It may seem counterintuitive that having a presence in a couple
dozen major backbones isnt enough to achieve commercial-
grade performance. However, even the largest of those networks
controls very little end-user access trafc. For example, the top
10 networks combined deliver less than one third of end-usertrafc, and it drops off quickly from there, with a very long tail
distribution over the Internets 13,000 networks. Even with direct
connectivity to all of the biggest backbones, the cloud applica-
tion must travel through the morass of the middle mile to reach
most of the Internets 1.4 billion users. Only a highly-distributed
architecture can overcome the middle mile challenge.7
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Akamais EdgePlatform:Optimizing the CloudAs computing moves into the public cloud, and as private
clouds scale to provide global access, Cloud Optimization
Services will be required to deliver the rigorous level of per-
formance and scalability needed for enterprises to realize thepromise of cloud computing. These services must go well
beyond CDN caching technologies in order to remove the
cloud-based barriers to successful enterprise cloud computing.
Akamai has built the worlds largest distributed cloud
optimization network, comprised of more than 48,000 servers
in 1,500 locations, across nearly 1,000 networks worldwide.
With its distinctive cloud optimization capabilities, Akamais
network will become the enabler that drives the success of the
cloud computing movement. The network leverages Akamais
proprietary technologies that overcome inefciencies in applica-
tion, transport, and routing layer protocols, along with unique
solutions that address the security and continuity of cloudservices together transforming the Internet into a reliable,
high-performance platform for cloud services, just as it has
done for thousands of online businesses and Web sites over the
last ten years.
Accelerating Cloud Computing Applications
As enterprises think about shifting from an on-premises
solution to a cloud-based offering, application performance
becomes a key consideration. Unfortunately, just like traditional
on-premises or hosted Web applications, cloud-based applica-
tions are typically deployed in a limited number of datacenters.
This results in slow and uneven application performance for the
reasons weve already described. Although caching services can
help with origin ofoad and performance for static Web sites,
it takes substantially more capabilities than a CDN to meet the
enterprise requirements for cloud computing performance.
First, unlike limited-footprint CDNs, Akamais highly-distributed
network enables delivery of content from the true edge of the
Internet, close to end users, in order to avoid as many middle
mile bottlenecks as possible.
In addition, Akamai leverages unique routing, communications,
and application optimization technologies to accelerate IaaS,
PaaS, and SaaS services across the cloud. We now take a closerlook at each of these technologies.
Path Optimization
Akamais SureRouteSM technology monitors real-time Internet
conditions to identify alternate paths over the Internet that are
faster than default BGP-dened routes. In addition to acceler-
ating the long-haul Internet communications that are neces-
sary for dynamic cloud applications and uncacheable content,
SureRoute also improves the reliability of these communications
by routing around trouble spots, nding alternative paths that
optimize connectivity.
When the Middle East cable cuts occurred in December 2008,for example, a Reuters article noted that the severed cables
were the most direct route for trafc between Western Europe
and the Middle East, and that, in the wake of the damaged ca-
bles, Verizon had re-routed some of its trafc sending it from
Europe across the Atlantic, the United States, the Pacic, and
then nally onto the Middle East.8 In situations like these, when
outages occur or when alternate routes force trafc across
continents and oceans, Akamais services enable consistent,
responsive performance. The graph below illustrates the results
of a performance test for a customer portal hosted in Europe,
as seen by Akamais Asia-Pacic measurement agents. These
agents measured a signicant degradation in performance
when trying to retrieve content from the origin during the twodays before repairs began. However, portal performance as de-
livered by Akamai remained consistent throughout the duration
of the cable cut, as Akamai was able to identify and send trafc
over alternative network paths on a real-time basis.
It is worth noting that this type of optimization requires routing
via an overlay server network and thus is only possible with a
massive and highly-distributed network like Akamais.
AKAMAI.HAS.A.DRAMATIC.IMPACT.ON.CUSTOMER.PORTALS.
100
80
60
40
20
0
Loss
Percentage
Origin
Akamai
1/27 1/29 1/31 2/2 2/4 2/6 2/8 2/10 2/12 2/14 2/16
Akamai protected this customer rom packet loss perormance issues ater the December 2008 Middle East cable cuts
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Communications Optimization
Akamai also streamlines data delivery between its servers by
using a proprietary transport-layer protocol that overcomes
TCPs and HTTPs inefciencies. The Akamai Protocol leverages
techniques such as:
Using persistent connections to eliminate the overhead in
connection establishment and teardown
Eliminating TCP slow-start and using optimal communications
window sizing based on knowledge of real-time network
latency conditions
Enabling intelligent retransmission after packet loss by lever-
aging network latency information, rather than relying on the
standard TCP timeout and retransmission protocols
Allowing multiple requests to be pipelined over a single con-
nection (without the need to wait for a response between
each request)
Simultaneously using multiple routes when warranted to en-
sure the fastest and most reliable communications possible.
While Akamais route optimization reduces the round trip time
(or latency) of server-to-server communications, these transport-
layer optimizations reduce the total number of round trips
required for a given communication. In fact, these two optimi-
zations work in synergy. TCP overhead is in large part a result
of a conservative approach that guarantees reliability in the
face of unknown network conditions. Because Akamais route
optimization delivers high-performance, congestion-free paths,
it allows for a much more aggressive and efcient approach
to transport-layer optimizations. Thus, these two approaches
work symbiotically to boost long-haul performance and improve
server efciency.
Application Optimization
Akamais application layer acceleration techniques include intel-
ligent prefetching and content compression. Compression can
greatly reduce the amount of data that must be transferred,
particularly for text objects like javascript and html. Prefetching
is a just-in-time caching technology that gives dynamic content
the same high levels of end user performance that edge cach-
ing provides for static content. With prefetching, Akamais edge
servers retrieve the embedded objects in an HTML page before
the browser requests them. The objects are then delivered to
the user from a local Akamai edge servers memory cache,
providing the end user with an optimal experience. Based on
customer-congured business rules, Akamai can also prefetch
hyperlinked content (such as a document or video) before auser clicks on it, enabling fast, local delivery of dynamically-
generated content.
Akamais cloud acceleration solutions leverage the optimizations
mentioned above to dramatically improve the end user experi-
ence and accelerate cloud application adoption. In the gure
below, for example, we see an illustration of the type of perfor-
mance gain achieved when using Akamais Web Application Ac
celerator service for an application running on Amazons EC2.
Application response times were at least twice as ast in Asia, Europe, and Australia with Akamai, compared to Amazons EC2 cloud inrastructure alone
Improvement in Performance by Continent (Global)
Australia
Asia
Europe
North America
Average Response Time
12.35s29.45s
14.71s59s
7.98s15.9s
5.54s7.93s
GLOBAL.SAAS.APPLICATION.RUNNING.ON.AMAZON.EC2.INFRASTRUCTURE.ACCELERATED.BY.AKAMAIS.WEB.APPLICATION.ACCELERATOR
Origin
Akamai
Distributed AkamaiEdge Servers
Application Acceler-ated over PublicCloud with Akamai
SaaS or CustomApplication Runningon Amazon EC2Infrastructure
AkamaiEdge Servers
Legend
Amazon EC2Datacenters
End User
End User
End User
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Akamai.and.Cloud.Computing:.A.Perspective.from.the.Edge.of.the.Cloud 8
Distributing Application Componentsto the Edge
The greatest possible application performance and scalability
are achieved when the application itself can be distributed
to the edge of the cloud, close to the end users. Akamai intro-
duced this ability nearly a decade ago with its EdgeComputing
offering that enables companies to deploy and execute J2EEapplications or application components on Akamais edge
servers. Application instances are automatically created in differ-
ent cities and regions based on real-time demand something
that cloud services such as Amazon EC2 and Google App
Engine cannot do. This allows EdgeComputing customers to
enjoy truly maintenance-free scalability in addition to unparal-
leled end user performance.
EdgeComputing is designed to work seamlessly within a hybrid
cloud environment. By deploying content-centric application
components such as site search, surveys and contests, or
page assembly at the edge of the cloud, while running
sensitive or transaction-oriented application components at theorigin infrastructure, the application can be scaled and the end
user experience can be optimized, while meeting the different
business requirements of each application component.
Securing Cloud Applications and Platforms
Because of their reliance on Web infrastructure, SaaS and other
applications running on public cloud platforms are as vulnerable
to Internet threats and service attacks as traditional Web sites
and applications. Akamais network acts as a secure perime-
ter that eliminates public entry points to cloud infrastructures,
helping to keep malicious DDoS attacks, Internet worms, hacker
threats, and attacks on application vulnerabilities outside the
origin data center.
Akamai also applies technologies such as DNS security, IP layer
protection and access control, HTTP origin cloaking, and ap-
plication request checking. As an additional layer of security,
Akamais SiteShield can completely cloak a Web site from
the public Internet by effectively removing the origin from the
Internet accessible IP address space, or Akamais in-cloud Web
Application Firewall can identify attacks in HTTP and SSL trafc
before they get to application servers, protecting cloud services
right from the edge of the cloud.
Ensuring Site and Application Availability
The Internet is an inherently unreliable medium, with failures
constantly occurring at all different levels from machine, to
data center, to network. In fact, this is one of the key reasons
cloud optimization services are so necessary to provide resil-
iency from the many potential pitfalls preventing the successful
delivery of cloud services to end users.
Akamai delivers this resiliency by starting with a network design
philosophy that embraces failure as a common occurrence
something the network must automatically and seamlessly
recover from. Indeed, Akamais network is so fault-tolerant
that it takes only an average of eight to 12 network operations
personnel at any given time to manage the more than 50,000
network devices (servers, routers, switches, etc.) worldwide that
delivers approximately 20% of the worlds Web content every day
Built on this zero-downtime infrastructure, Akamais cloud
optimization services includes Site Failover, offering multiple op-
tions for enterprise business continuity in case of origin or cloud
server failure. In addition, while most of Akamais solutionsenable cloud providers to leverage the Akamai network as a vir-
tual extension of their own, Akamai also offers service options
that allow cloud providers access to Akamai networks intel-
ligence. Akamais Global Trafc Management is a cloud-based,
highly-scalable, on-demand service that allows an enterprise to
balance trafc between multiple entities based on a variety of
business policy and Internet performance factors. Providers can
leverage this network intelligence to boost the performance
and reliability of their own multi-site infrastructures, whether or
not they choose to augment that infrastructure with Akamais
massive network.
These service options, combined with a 100% uptime SLA,enable enterprises to leverage cloud computing in any form
they wish while maintaining the rock-solid availability their
businesses demand.
ConclusionAs one of todays hottest IT topics, cloud computing is covered
daily across the press, from academic journals to technology
blogs, and even the travel section of the New York Times.9 Mos
of the hype has focused on offerings in the public cloud, where
centralized architectures are currently commonplace. The draw-
backs of this type of architecture have already begun to surface
as many of the major cloud vendors have suffered widely-re-ported outages and downtime over the last year. Now, as cloud
computing moves out of hype and experimentation mode into
more mainstream adoption, businesses running applications on
cloud platforms will rely on Akamais cloud optimization services
to make the cloud responsive, scalable and secure.
Cloud Computing wont have a single vendor or a single cloud
answer; its incarnations will be as varied as the applications
and services it supports. As The Economistrecently stated,
The computing sky will probably always be cloudy, meaning
that there will be many private and public clouds, and they will
come in all shapes and sizes. And most of them will be inter-
connected.10
But regardless of the path the cloud computingevolution takes, Akamais cloud optimization services will play a
critical role in driving its growth, with innovative solutions that
enable success for both cloud computing providers and the
enterprises that use them.
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Akamai.and.Cloud.Computing:.A.Perspective.from.the.Edge.of.the.Cloud 9
The Akamai Difference
2010 Akamai Technologies, Inc. All Rights Reserved. Reproduction in whole or
in part in any form or medium without express written permission is prohibited.
Akamai and the Akamai wave logo are registered trademarks. Other trademarks
contained herein are the property of their respective owners. Akamai believes that the
information in this publication is accurate as of its publication date; such information
is subject to change without notice.
Akamai provides market-leading managed services for powering rich media, dynamic transactions, and enterprise applications online. Having pioneered the content delivery marke
one decade ago, Akamais services have been adopted by the worlds most recognized brands across diverse industries. The alternative to centralized Web infrastructure, Akamais
global network of tens of thousands of distributed servers provides the scale, reliability, insight and performance for businesses to succeed online. Akamai has transformed the Intenet into a more viable place to inform, entertain, advertise, interact, and collaborate. To experience The Akamai Difference, visit www.akamai.com.
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k i
1 Signicant portions of the content in Section 3 of this whitepaper are taken from this authors article, Improving Performance on the Internet, published in the Febru
2008 issue of Communications of the ACM.
2 http://www.broadband-forum.org/news/download/pressreleeases/2008/400million.pdf
3 http://www.renesys.com/blog/2008/10/wrestling-with-the-zombie-spri.shtml
4 http://news.cnet.com/8301-10784_3-9878655-7.html
5 http://www.telegeography.com/cu/article.php?article_id=21528
6 http://www.renesys.com/blog/2008/12/deja-vu-all-over-again-cables.shtml
7 For a more in-depth examination of Internet bottlenecks and the benets of highly-distributed networks, please see this authors article,
Improving Performance on the Internet, published in the February 2008 issue of Communications of the ACM
8 http://www.reuters.com/article/internetNews/idUSTRE4BJ0FV20081220
9 Cohen, Billie, In the Cottage, Yet Industrious, New York Times, April 16, 2009.
10 Gathering Clouds, The Economist, March 19, 2009.