Whatever happened to the IPv4 address crisis?

In February 2011, the global Internet Assigned Numbers Authority (IANA) allocated the last blocks of IPv4 address space to the five regional Internet registries. At the time, experts warned that within months all available IPv4 addresses in the world would be distributed to ISPs.

Soon after that, unless everyone upgraded to IPv6, the world would be facing a crisis that would hamper Internet connectivity for everyone. That crisis would be exacerbated by the skyrocketing demand for IP addresses due to a variety of factors: the Internet of Things (refrigerators needing their own IP address); wearables (watches and glasses demanding connectivity); BYOD (the explosion of mobile devices allowed to connect to the corporate network); and the increase in smartphone use in developing countries.

So, here we are three years later and the American Registry for Internet Numbers (ARIN) is still doling out IPv4 addresses in the United States and Canada.

Whatever happened to the IPv4 address crisis?

Read this article as originally published on NetworkWorld.com.

The day of reckoning still looms – it’s just been pushed out as the major Internet players have developed ingenious ways to stretch those available numbers. But these conservation efforts can only work for so long.

ARIN currently has “approximately 24 million IPv4 addresses in the available pool for the region,” according to President and CEO John Curran. They’re available to ISPs large and small, but Curran predicts they will all likely be handed out by “sometime in 2014.”

Even then, addresses will still be available to be assigned to the operators’ clients for a while longer. And not all operators are likely to experience shortages at the same time. “It’s more of a problem for networks that are growing. For networks that are stable, they can reuse addresses” as some customers drop their service and new ones sign up.

Phil Roberts, technology program manager for the Internet Society, adds, “There’s some anticipation in using addresses. Network operators get a block and parcel them out – you don’t get them right when you need them.”

How did we get here?

The problem took no one by surprise. The Internet Engineering Task Force (IETF) foresaw the global growth of network-connected devices 20 years ago, and in response drafted a new version of the Internet Protocol to address the looming shortage.

IPv6 uses a 128-bit address space – that is, 2^128 – yielding far more potential addresses than IPv4′s 32-bit scheme, and in fact more addresses than there are grains of sand in the Earth’s crust.

So, why hasn’t everyone just switched over to IPv6?

Well, IPv6 is not backward compatible with IPv4, meaning network operators need to run a dual stack IPv4/IPv6 network for years to come. And for IPv6 to work, it needs to be implemented end to end, meaning IPv6 has to be enabled by network hardware vendors, transit providers, access providers, content providers, and endpoint hardware makers.

Since there’s no economic incentive to being the first to invest in revamping your protocol support, many hardware and service providers stood on the sidelines and waited for momentum to build.

For enterprises, it made no sense to upgrade to IPv6 if their ISPs were still running IPv4. As John Brzozowski, fellow and chief architect for IPv6 at Comcast Cable, puts it: We had a chicken-and-egg problem. “Service providers didn’t want to implement IPv6 because the content providers weren’t there, and content providers didn’t want to implement it because the service providers weren’t there.”

Plus, there were ways to avoid having to face the IPv6 music. One common technique is carrier-grade network (CGN) address translation (NAT), which translates private IP addresses within a carrier’s network to a smaller number of public IP addresses in much the same way that ordinary NAT lets individuals and organizations use multiple internal IP addresses.

However, CGN brings with it a number of issues that limit its appeal. For one thing, it’s expensive for carriers, and the money they spend on it could be more productively applied to IPv6-ready hardware. For another, a great deal of Internet infrastructure relies on the premise that a single public IP address uniquely identifies a carrier subscriber. CGN breaks that assumption, which means that it breaks geolocation services and impedes law enforcement organizations’ ability to identify users.

Carriers can also purchase surplus IP addresses from other carriers. ARIN has a well-defined process that lets organizations transfer IPv4 addresses. Some organizations have also transferred addresses without ARIN approval – what some have called a black market in IPv4 addresses.

ARIN is also helping to ease the pain by reclaiming unused addresses from, say, ISPs that have gone out of business, although that number is relatively small and won’t materially affect the date upon which all IPv4 addresses are gone. ARIN is also now parceling out smaller and smaller blocks of IPv4 numbers and tightening the criteria for approval of new addresses.

But IPv4 workarounds will only last for so long and most organizations are recognizing that fact and moving, if grudgingly, to IPv6. Roberts says, “There’s a light at the end of the tunnel.”

Where are we headed?

Comcast recently announced that it now has the world’s largest IPv6 deployment. In a post on Comcast’s site, Brzozowski said, “Today, over 25 percent (and growing) of Comcast’s Xfinity Internet customers are actively provisioned with native dual-stack broadband Internet service. Native IPv6 support has been deployed to over 75 percent of our broadband network, and our goal is 100 percent in early 2014.”

Not all service providers have been as proactive, however. According to Internet Society measurements, Verizon shows no IPv6 presence.

All the major enterprise router vendors, and most vendors of small office routers, offer products with IPv6 support. A growing ISP or an expanding business should have no trouble finding hardware that supports IPv6.

As with IPv6 deployment among access providers, deployment among content providers is growing. Among websites, according to Roberts, the five top sites as measured by Alexa all support IPv6, and they account for a substantial portion of total IP traffic. One of those sites, Google, continually collects statistics about IPv6 adoption and shares them in a graph whose curve shows a steady upward trend.

However, while the shape of the curve is encouraging, in absolute terms the number of users accessing Google via IPv6 is barely above 3% of all users. Still, “that’s more than double what it was a year ago,” Roberts says, and IPv6 traffic is growing at a faster rate than IPv4, which Roberts sees as a promising sign.

The Internet Society also makes ongoing measurements of IPv6 deployment on its World IPv6 Launch site. It shows that 13 percent of the Alexa Top 1,000 websites are currently reachable over IPv6. “That number was 10 percent a year ago,” Roberts said. In addition, the Internet Society checks the number of network operators who are turning on IPv6. “The first time [we reported on the statistics] we had about 70 networks,” Roberts says. “Now we’re up to 226.”

With endpoint hardware providers, IPv6 readiness is a mixed bag. “A lot of devices in the home don’t use it yet,” Roberts says. However, the fast-growing cell phone market is a different story. Cell carriers are making progress supporting IPv6-enabled devices. For instance, Roberts points to Verizon Wireless. “All of its new smartphones have IPv6 enabled,” he says, and T-Mobile recently announced that its Android 4.4 phones will default to IPv6 only for connecting to its mobile network.

Some gaming console manufacturers too are jumping on the bandwagon. In October, Microsoft’s Chris Palmer announced at NANOG 59 that the Xbox One gaming console will use IPv6 with IPsec for peer-to-peer communication between gamers, and said that performance will be best when end-to-end communication is over IPv6.

That end-to-end, IPv6 connection may be elusive when content delivery networks are involved. Some CDNs, such as Limelight, turn on IPv6 by default for their customers, but others, such as Akamai, do not. Akamai’s Erik Nygren says, “Most of our customers have very rich environments that still require end-to-end testing prior to dual-stacking.”

One problem is that customer-premises equipment (CPE) has to be capable of supporting IPv6 and properly configured to do so, and not all CPE currently in production can claim that. Nevertheless, Akamai reported in June that roughly 1.5 percent of the content requests it sees come in over IPv6 – a rate that is about double what it saw a year previously.

Over the entire network ecosystem, including carrier hardware and networks, CDNs, corporate networks, home electronics, mobile devices, and content providers, there is steady progress in IPv6 implementation.

Bottom line

Unallocated IPv4 address blocks are gone forever. However, carriers still have IPv4 addresses available for allocation, so IPv4 addresses will remain in use for some time to come. And though there may be no immediate crisis for service providers, businesses, or customers, there is steady pressure to enable IPv6 in every segment of the network ecosystem as the best way to address IPv4 address scarcity.

No one seems willing to predict a date by which the last IPv4 packet will traverse the Internet backbone, but we are seeing clear progress toward IPv6 critical mass in the form of dual-stack implementations in enterprise, mobile, and home-based devices and operating systems.

Once it becomes clear we’ve reached an inflection point, when service and content providers can count on dual-stack users, and users can count on the availability of IPv6-enabled content, the pace of adoption should quicken. Just as no one needs to be the first to support IPv6, no one wants to be last either.

The reality is, Roberts says, “It takes a while to transition. After all this is done it would be a great graduate thesis for someone to see why it has taken so long.”

Copyright 2014 by Network World, Inc., 492 Old Connecticut Path, Framingham, Mass. 01701. Reprinted by permission of Network World. All rights reserved.

4 Android e-reader apps: The latest word in reading

Sometimes you just don’t have room in your bag to carry a paperback, magazine or tablet-sized e-reader device. So why not make use of the smartphone you already have with you? Your Android phone makes a perfectly good e-reader, especially with the right software.

Read this article with screenshots on Computerworld.com.

I spent a week using four of the most popular, highly rated e-reader apps in the Google Play Store: Aldiko Book Reader, Cool Reader, FBReader and Moon+ Reader. Each app was installed and tested on a Samsung Galaxy Note II, whose 5.5-in. screen strikes a good balance between portability and page size.

Note that we have not included apps that are designed primarily to open content that lives in the cloud, or that are built to focus on a specific shopping source, such as Kindle, Nook and Google Play Books. All of these apps are designed to let you read books that you download directly onto your device.

Each of the four covered here supports multiple e-book formats, multiple typefaces and a variety of text display options.

Aldiko Book Reader

Aldiko Ltd.
Versions: Free, Premium ($2.99)
Formats supported: ePub, PDF
Languages: 12
Pros: Supports PDFs, allows you to sort books into self-defined collections
Cons: Minimal customization options, no status bar

Aldiko is a serviceable e-reader with moderate ability to customize the reading experience.

If you don’t have a book ready to read on your device, Aldiko lets you browse and buy books through Feedbooks and three other online book catalogs, and lets you add additional catalogs by specifying a URL.

If you want to read a book that’s already on your device, Aldiko lets you browse the device’s file system and open ePub and PDF files. If you want Aldiko to save your place between reading sessions, however, you must import the book into Aldiko — a step the other apps do automatically when you open the book.

Importing a book puts it on a virtual shelf in Aldiko’s library, which you can browse by title, author, tag or collection. You can group related documents by defining your own tags and collections — so you can have collections such as “to read” or “19th century novels,” or tags such as “science fiction.”

Aldiko comes bundled with a single default font, but you can download a dozen more with one tap. You can adjust font sizes in whole-pixel increments and margins in 10-pixel increments. If the standard black type and white background doesn’t appeal to you, you can choose among dozens of pre-selected font and background colors, and save those selections to one of two themes, labeled Day and Night. However, Aldiko doesn’t let you create your own colors via selection sliders as the other apps do.

With a book open, a tap in the middle of the screen or on the menu soft key (the common ways to bring up the settings screens for all these apps) displays icons at the bottom that let you view the book’s table of contents, change the theme and set the font size. I found Aldiko’s menu structure a little confusing, however. For instance, to get to the main configuration options screen, where you can change not only display options but also toggle page numbers and page turn animations, you must tap the font size icon, then tap “More.”

In contrast with the other e-reader apps, Aldiko’s main screen lacks a status bar that shows you how far you are through a book or chapter. You can set bookmarks that allow you to return to a specific point in a book, but you can access those bookmarks only from within each book (rather than allowing you to see them whether or not the book is open). Aldiko does let you search for a particular phrase or jump to a specific numbered page.

If you long-press to select a word or phrase, you can look it up on the Web (using Google’s “define” feature), search for it within the rest of the document or share it via another app. If you have the Premium version, you can also add notes and highlights to selected text — a feature Moon+ Reader offers in its free version.

Aldiko is light on fancy extras. For instance, it offers only a single page-turning animation — a sliding page — that you can toggle on or off. It also lacks any way to customize gestures to control the app, other than letting you choose to either use the volume keys or touch the sides of the screen to turn a page.

Bottom line

Aldiko offers fewer configuration options than the other apps, but if you want to use an e-reader for PDF files, it’s the most economical of the four reviewed here, as it’s the only one that supports PDF files in a free edition.

Cool Reader

Vadim Lopatin
Version: Free
Formats supported: ePub, Mobi, HTML, DOC/RTF, text, FB2,TCR, CHM, PDB
Languages: 16
Pros: Good display customization and gesture control options, bundled manual
Cons: No indication of progress within chapters, below-average title bar options

Cool Reader is an ambitious e-reader with a text-to-speech feature that none of the other programs offers for free, but it’s not the most sophisticated app of the group.

Cool Reader makes books available in several ways from its opening screen, which appears when you start the program (and if no book is already open). You can open the book you’re currently reading or any recently read books, or browse for unread books in the file system or in any of seven bundled online catalogs — or you can add your own. If a book is already open, getting to that screen is a little tricky. You have to tap to bring up the app’s pop-up options icons and then tap the one labeled Root.

Cool Reader offers six fonts: one monospace, one serif and four sans serif. You can add additional fonts by placing TTF files in the Fonts directory of your device (according to the Cool Reader manual); similarly, you can add your own background images if none of the 30 provided with the program satisfy you. You can set font size and top, bottom, left, and right margins in single-pixel increments.

The app has a day/night toggle that switches between two sets of font and background settings; the day/night setting can also change the brightness of the screen.

Cool Reader can display a status bar, which it calls a title bar, at the top of the screen — there’s no way to display it at the bottom. You can configure the title bar’s typeface, size and color. It can show you (optionally) the book title, page number, page count, chapter marks and percentage read, as well as the device’s battery level. (The app displays its Eastern European origin by its use of a comma rather than a decimal point in the percentage-read number). Unfortunately it doesn’t show your progress within your current chapter or story, as Moon Reader+ can.

The app also has an optional toolbar (that you can display on either side of the screen) that contains icons that take you to your library, the book’s table of contents, search, options and other settings.

When reading, you can choose to use a document’s internal style settings, but if you’d rather control styles yourself, Cool Reader gives you direct access to a wide range of format settings for paragraphs and other elements, such as titles and links.

The app also gives you a lot of options for gestures to control your reading experience. Cool Reader divides the screen into a 3×3 grid, and you can specify two actions for each zone, such as next or previous page, forward by 10 pages, or toggle day/night display. You can change screen brightness by flicking up and down on the left or right edge of the screen. You can select text to copy it to the clipboard, find it in the dictionary, add it as a bookmark or search with it. And you can set any of three page-turning animation options.

In Cool Reader, tapping on the center of the screen or the menu button brings up more options than does a similar action in the other programs. You get nine icons that take up the bottom third of the screen, one of which, “More,” leads to 10 additional icons. Collectively, these icons let you control the app’s operations — navigate within a book via search, go to a bookmarked page, jump to a particular page or see progress percentage, and more. One of the icons, Options, lets you change the app’s settings.

Cool Reader’s process for selecting a word or a phrase is awkward. Rather than using a long press, you must tap one of the pop-up icons to toggle selection mode. You highlight your selection, and Cool Reader then displays icons that let you copy the text to the clipboard, look it up in a dictionary, bookmark it, share it or search for it within the document.

Cool Reader bundles links to 10 dictionaries, but you must install any that you want to use.

The app includes text-to-speech capabilities to read your text to you in a robotic voice. It also has a feature called Autoscroll, but rather than moving the entire screen up at the pace at which you read, it repaints the entire screen with the next page of text — sort of an automatic super-slo-mo page turn automation.

One nice touch (unusual in a mobile app) is a comprehensive manual that explains the app’s concepts, menus and settings. And if you like Cool Reader on your Android phone, you can also download versions that run on Windows and Linux platforms from the app’s home page.

Bottom line

Cool Reader offers a broad range of supported e-book formats, top-notch ability to tailor CSS settings and some innovative features, such as its tap zones and text-to-speech. However, it also exhibits surprising awkwardness in its menu arrangement and text selection, making the overall reading experience not quite as smooth as it could be.


FBReader.Org Ltd.
Version: Free
Formats supported: ePub, Mobi, HTML, DOC/RTF, text, FB2
Languages: 30
Pros: Many bundled online catalogs, with multi-catalog search
Cons: Limited font selection, limited gesture customization

FBReader lets you customize your screen display as well as any e-reader, but it’s a little light on options for controlling the reading process via gestures.

Unlike the other e-readers listed here, only the Android menu soft key brings up FBReader’s settings. Tapping the center of the screen displays a title bar that lets you browse your local and network libraries and the table of contents of the open document. From the library screen you can search for books by recently read, author, title, series or tag — or browse the file tree.

FBReader comes bundled with eight online catalogs from which you can download books, and an equal number of disabled ones for books in other languages that you can enable by ticking a box on the Manage Catalogs screen. It’s also easy to add additional catalogs of your own, if you wish. You can search for a specific title either within each catalog or within all the defined catalogs at once, but the latter search took about a minute and a half to complete on my device.

For the reading window, FBReader offers only four fonts: one monospace, one serif and two sans serif. You can set separate display styles for regular paragraphs, titles, headers, hyperlinks and other types of text. You can set top, bottom, left and right margins in single-pixel increments.

Like other e-readers, FBReader lets you toggle between a day and a night theme. Within each theme, you can customize the colors of not only regular text and background, but also visited and unvisited hyperlink text, selected text, the backgrounds for selections and search results. You can also set the background to one of three wallpapers: sepia, leather or wood. FBReader has three different page-turning animations.

When a document is open, FBReader can show your reading progress with a vertical slider or progress bar, or it can display a horizontal footer that acts as a status bar, showing a reading progress indicator and (optionally) a page number, clock, battery level and TOC marks. You can tap on the status bar to display a slider control to move around in the book. FBReader also displays an optional “action bar” at the top with icons that let you choose another book or move through the current book’s table of contents. You can toggle the action bar off for more viewing area.

If you select a word or phrase, you can copy it to your clipboard, look it up, bookmark it or send it to another application. FBReader lets you find bookmarks in a single document or all documents at one time. The app comes bundled with four dictionaries you can choose from.

FBReader has a limited number of gesture settings. You can set whether to turn pages by a screen tap or flip and/or with the device’s volume keys, and whether to use a double-tap to bring up a navigation menu.

I ran into a couple of minor bugs in FBReader. You’re supposed to be able to select a book from an external memory card in the file tree, but tapping the icon for the memory card takes you to internal storage instead. And the setting to hide the status bar didn’t do so.

Note: Unlike Aldiko and Moon+, FBReader is available outside of the Android ecosystem; it supports Linux, Mac OS X, Windows, BlackBerry 10 and a variety of lesser-known platforms. (Interestingly, though, it does not have an iOS version.)

Bottom line

I liked reading with FBReader. The Droid Serif font (which the other apps also offer) is rendered nicely, and I could set margins, text spacing and CSS options to make my books easy to assimilate. I didn’t mind the app’s limited gesture support. FBReader is a great e-reader option that just exhibits slightly less finesse than Moon+ Reader.

Moon+ Reader

Moon Reader Ltd.
Versions: Free,
Pro ($4.99)
Formats supported: ePub, Mobi, PDF (Pro version only), HTML, text, CHM, CBR, CBZ, UMD, others
Languages: 40
Pros: Interface and gesture settings are highly customizable. Ability to attach notes to words and phrases. Ability to save multiple display themes.
Cons: Improper handling of blockquote tag in HTML documents

Of these four e-reader apps, Moon+ Reader gives you the finest-grained control over display settings and the greatest number of options for configuring control gestures, along with a couple of unusual and useful features.

Moon+ Reader’s home screen lets you browse a bookshelf of files you’ve opened, browse your file system or open a list of five online catalogs, to which you can add your own. The Pro version has a Statistics page that shows the number of books on your shelf, read books, reading hours and pages turned.

The reading experience in Moon+ Reader stacks up to any e-reader and goes even further. The app’s status bar displays your reading progress not only for the document as a whole, but also within the current section or chapter. However, I did notice one flaw in document rendering: The blockquote tag in HTML documents is not properly indented. FBReader has the same problem, but Cool Reader gets it right.

Tapping on the center of the screen or pressing the menu button while you’re reading a book displays a progress slider at the top of the screen that you can use to move around within a document. At the same time, an icon bar at the bottom lets you change display options, start autoscrolling, access bookmarks and the table of contents, and change all of the app’s settings.

Moon+’s settings are grouped into visual options, control options and miscellaneous. The visual options let you choose from among dozens of typefaces, including serif, sans serif and monospace, bold and italic, and non-Latin fonts, many for Indian languages. Sliders let you specify any solid color for the type or background, or you can pick from 10 background images, all of which are suitably muted.

You can adjust font sizes, but unlike the other apps, which seem to measure font size in pixels, Moon+ seems to use points, and lets you adjust fonts in increments of 0.1 points. You can specify the width of the left, right, top and bottom margins in single-pixel increments. The font and margin controls are plus and minus buttons, so you can make things a little bigger or smaller without having to choose a particular number from a list. Also, you can animate page turns in seven different ways, or not at all.

You can save all your visual options as a theme, so different people who use the same device can view books just the way they like. The app comes with a dozen preset themes, rather than the binary day/night choices common in other apps.

The control options let you specify portrait or landscape orientation, or have the software sense which way you’re holding the phone. You can also specify actions to take when you tap the screen in different places, press various keys or make finger gestures.

Under “miscellaneous” you’ll find options to autoscroll as you read (with five different scrolling methods), keep a line from the previous page when paging, automatically indent the first line of each paragraph and many more.

If you tap on a word or phrase you can copy it, highlight it, attach a note to it, look it up, search for it within the rest of the document, translate it via Google Translate or look it up on Google or Wikipedia. The app bundles the ColorDict dictionary, but you can choose from half a dozen different dictionary options, including specifying a custom online dictionary.

Moon+ also lets you add bookmarks and, as with FBReader, you can view all the bookmarks in one or all of your documents from a single screen and go to any with a tap.

Moon+ Reader Pro, which costs $4.99, adds support for PDF files, text-to-speech and more. It can also integrate with Dropbox or Google Drive, so that if you sync your e-books to those repositories, the app can open them without your having to take the extra step of downloading them to your device.

Bottom line

Moon+ Reader was my favorite of these four apps. I was able to find a typeface I liked better than any in the other apps, and I liked its status bar best. I also appreciated the fact that bringing up settings while reading a book presented icons that let me quickly perform the actions that I would be most likely to take.


Some bibliophiles eschew e-readers because, they say, they like the feel of a book and the act of turning pages. If you’re one of these individuals, you may be surprised at how quickly you get used to the convenience of a library in your pocket, the ease of turning pages with a single tap and the small pleasure of never needing a bookmark again.

Of these apps, Moon+ Reader won me over thanks to its sophisticated display options, range of gesture controls and informative status bar. But if your e-reading sensibilities differ from mine, it costs you only a little time to try several apps and find the one that best suits you and your particular needs.

Copyright 2014 by Computerworld Inc., 492 Old Connecticut Path, Framingham, Mass. 01701. Reprinted by permission of Computerworld. All rights reserved.

Cloud Computing 101: SaaS, PaaS, and IaaS

If you’re just starting to research cloud computing, you may get a little confused about all the cloud configurations available to you. You’ve probably heard terms and abbreviations such as Software-as-a-Service (SaaS), Platform-as-a-Service (PaaS), and Infrastructure-as-a-Service (PaaS), and learning how they differ might seem daunting. Consider this a primer – Cloud Computing 101.


If you’ve had any experience with cloud computing already, it’s likely to have been with SaaS. Salesforce.com pioneered this delivery model more than a decade ago, and it has become a profitable business model for large numbers of businesses. In SaaS, rather than purchasing a license for software and installing it on in-house hardware, you contract with an application service provider that runs software on its own hardware and provides you with credentials to access it.

SaaS has some attractive benefits. With it, you no longer have to buy or support hardware for each application, which can reduce your capital expenditures and, potentially, personnel costs for administration staff. You pay as you go, generally as an operational rather than a capital expense. Because SaaS applications are priced competitively with on-premise alternatives, but without the need for hardware on which to run them, total costs are therefore generally lower. SaaS applications tend to be updated more frequently than packaged software, and you always run the most up-to-date version. Users typically connect with SaaS applications through a secure channel, using HTTPS and sometimes virtual private networks (VPN), and interact with them via a familiar web browser.

However, there are tradeoffs to using SaaS as well. Your data is stored on your providers’ servers, which may complicate things for organizations that have regulatory governance restrictions imposed upon them by legislation such as HIPAA or PCI. Because the applications run remotely, they may be subject to network latency, which users experience as slow response times, or even downtime (though infrastructure failure can be an issue with in-house applications too). SaaS applications don’t always integrate well with other vendors’ applications, including those you may already be running in-house, and it may be challenging to migrate away from any given vendor should you choose to switch.

Nevertheless, the SaaS model is a popular choice for applications of all scope, from niche applications to enterprise suites for human resources management (HRM) and enterprise resource planning (ERP). Among the many SaaS vendors are Salesforce.com, Dropbox, QuickBooks, and Microsoft Office 365.


If SaaS is like going to a restaurant and being presented with a meal, PaaS is like being given access to a fully stocked kitchen. It’s an excellent option if your primary business is preparing food software. As with SaaS, PaaS providers host software on their own hardware and charge organizations a fee for their resources.

The “platform” part of PaaS involves a software stack that includes infrastructure services (networking, load balancing, security), application services, operation services, and APIs for working in languages such as Java, PHP, Ruby, Python, and Perl. With these tools, developers can build custom cloud-based applications and integrate them with the PaaS provider’s other resources, including a deployment infrastructure and managed hosting services. PaaS services let organizations develop, test, deploy, and host applications.

One potential downside of PaaS, as with SaaS, is vendor lock-in. If your PaaS provider doesn’t do all you want, it may not be easy to change platforms without giving up all you’ve developed on your current platform. And not all PaaS providers support all the languages you may want to use.

PaaS providers include Amazon Web Services (AWS) Elastic Beanstalk, Google App Engine, Microsoft’s Windows Azure, Engine Yard, Heroku, Salesforce.com’s Force.com, and Red Hat OpenShift.


To extend the food prep metaphor, IaaS is like being given an empty room and told to customize the kitchen of your dreams – or a living room or game room.

IaaS vendors provide only the underlying compute, storage, and networking resources. Their clients can customize and deploy them in whatever ways suit their business, and use whatever development tools or methodologies work best for them. Businesses are responsible for maintaining the resources they use, but they pay only for the whatever resources they deploy, and only for as long as the resource infrastructure is running.

Two main varieties of IaaS are public and private clouds. Public cloud vendors provide pay-as-you-go infrastructure services over the public Internet. They use a multi-tenant model, in which server resources are shared by multiple customers. By contrast, a private cloud is for the exclusive use of a single organization. You can install and manage a private cloud at a hosting provider’s facility or in your own data center.

Well-known IaaS public cloud platforms include AWS Elastic Compute Cloud (EC2), Google Compute Engine, Windows Azure (yes, it’s both PaaS and IaaS), and Rackspace. Private cloud platforms include OpenStack and CloudStack. Some organizations uses resources from both public and private clouds to maintain a single application. This combination is referred to as a hybrid cloud.

Obligatory plug for my (now former) employer

With any sort of cloud computing, but especially with IaaS, it helps to have a hand to hold as you venture in for the first time. RightScale has seven years of experience at helping organizations get started on the cloud, and our customers have launched more than five million servers to date. The RightScale CloudSight program provides professional consulting that helps companies define a cloud roadmap, assess their application portfolio, design cloud architectures, and create implementation plans. When you’re done planning and are ready to roll out cloud services, we offer pre-built templates for most common use cases and popular operating systems and applications. We also offers PlanForCloud.com, a free cloud cost forecasting tool based on a global database of price points from multiple cloud providers, which enables organizations to perform sophisticated cloud cost forecasting.

When you’re ready to get serious about cloud computing, try RightScale Cloud Management for free.

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