---

Amazon CloudFront Functionality

Amazon CloudFront has a simple, web services interface that lets you get started in minutes. In Amazon CloudFront, your content is organized into distributions. A distribution specifies the location or locations of the original version of your files. A distribution has a unique CloudFront.net domain name (e.g. abc123.cloudfront.net) that you can use to reference your objects through the global network of edge locations. If you wish, you can also map your own domain name (e.g. www.example.com) to your distribution. You can create distributions to either download your content using the HTTP or HTTPS protocols, or stream your content using the RTMP protocol.

To use Amazon CloudFront, you:

• Store the original versions of your files on one or more origin servers. An origin server is the location of the definitive version of an object. Origin servers could be other Amazon Web Services – an Amazon S3 bucket, an Amazon EC2 instance, or an Elastic Load Balancer – or your own origin server.

• Create a distribution to register your origin servers with Amazon CloudFront through a simple API call or the AWS Management Console. When configuring more than one origin server, use URL pattern matches to specify which origin has what content. You can assign one of the origins as the default origin.

• Use your distribution’s domain name in your web pages, media player, or application. When end users request an object using this domain name, they are automatically routed to the nearest edge location for high performance delivery of your content.

• Pay only for the data transfer and requests that you actually use.

• Amazon CloudFront's availability is backed with the Amazon CloudFront Service Level Agreement.

---

Service Highlights

Fast Using a network of edge locations around the world, Amazon CloudFront caches copies of your static content close to viewers, lowering latency when they download your objects and giving you the high, sustained data transfer rates needed to deliver large popular objects to end users at scale. Requests for your dynamic content are carried back to your origin servers running in Amazon Web Services (e.g., Amazon EC2, Elastic Load Balancing) over optimized network paths for a more reliable and consistent experience. These network paths are constantly monitored by Amazon and connections from CloudFront edge locations to the origin are reused to serve your dynamic content with the best possible performance.

Simple A single API call lets you get started distributing content from your Amazon S3 bucket or Amazon EC2 instance or other origin server through the Amazon CloudFront network. Or, interact with Amazon CloudFront through the AWS Management Console’s simple graphical user interface. There is no need to create separate domains for your static and dynamic content. With CloudFront, you can just use the same domain name to point to all of your website content. Any changes you make to your existing configuration take effect across the entire global network within minutes. Plus, since there’s no need to negotiate with a sales person, you can get started quickly and begin delivering your entire website using Amazon CloudFront.

Designed for use with other Amazon Web Services Amazon CloudFront is designed for use with other Amazon Web Services, including Amazon S3, where you can durably store the definitive versions of your static files, and Amazon EC2, where you can run your application server for dynamically generated content. If you are using Amazon S3 or Amazon EC2 as an origin server, data transferred from the origin server to edge locations (Amazon CloudFront “origin fetches”) will be billed at a lower price than Internet data transfer out of Amazon S3 or Amazon EC2. Amazon CloudFront also integrates with Elastic Load Balancing. For instance, you can deploy your web application on Amazon EC2 servers behind Elastic Load Balancing and use Amazon CloudFront to deliver your entire website. Pricing for all AWS services is available here.

Cost-Effective Amazon CloudFront passes on the benefits of Amazon’s scale to you. You pay only for the content that you deliver through the network, without minimum commitments or up-front fees. This applies for any type of content that you deliver – static, dynamic, streaming media, or a web application with any combination of these.

Elastic With Amazon CloudFront, you don’t need to worry about maintaining expensive web-server capacity to meet the demand from potential traffic spikes for your content. The service automatically responds as demand increases or decreases without any intervention from you. Amazon CloudFront also uses multiple layers of caching at each edge location and collapses simultaneous requests for the same object before contacting your origin server. These optimizations further help reduce the need to scale your origin infrastructure as your website becomes more popular.

Reliable Amazon CloudFront is built using Amazon’s highly reliable infrastructure. The distributed nature of edge locations used by Amazon CloudFront automatically routes end users to the closest available location as required by network conditions. Origin requests from the edge locations to AWS origin servers (e.g., Amazon EC2, Amazon S3, etc.) are carried over network paths that Amazon constantly monitors and optimizes for both availability and performance.

Global Amazon CloudFront uses a global network of edge locations, located near your end users in the United States, Europe, Asia, and South America.

---

Pricing

Pay only for what you use. There is no minimum fee. Estimate your monthly bill using the AWS Simple Monthly Calculator.

On-Demand Pricing

Regional Data Transfer Out (per GB)

Request Pricing (per 10,000)

We charge less where our costs are less, thus some prices vary across geographic regions and are based on the edge location through which your content is served. There may be higher fees associated with any new edge locations we add to the CloudFront network in the future. Usage tiers for data transfer are measured separately for each geographic region. The prices above are exclusive of applicable taxes, fees, or similar governmental charges, if any exist, except as otherwise noted. Effective January 1, 2010, the prices for usage out of Japan edge locations are inclusive of Japan consumption tax. The prices for usage out of Australia edge locations are exclusive of Australia Goods and Services Tax (GST).

Invalidation Requests

No additional charge for the first 1,000 files that you request for invalidation each month. $0.005 per file listed in your invalidation requests thereafter.

Custom SSL Certificates

You pay $600 per month for each custom SSL certificate associated with one or more CloudFront distributions. This monthly fee is pro-rated by the hour. For example, if you had your custom SSL certificate associated with at least one CloudFront distribution for just 24 hours (i.e. 1 day) in the month of June, your total charge for using the custom SSL certificate feature in June will be (1 day / 30 days) * $600 = $20.

Origin Server

With Amazon CloudFront, you can use an AWS origin (e.g., Amazon S3, Amazon EC2, Elastic Load Balancing, etc.) or your own origin servers to store the original, definitive versions of your files. If you are using Amazon S3 or Amazon EC2 as an origin server, data transferred from the origin server to edge locations (Amazon CloudFront “origin fetches”) will be billed at a lower price than Internet data transfer out of Amazon S3 or Amazon EC2. Pricing for all AWS services is available here.

Price Classes

Price classes provides you an option to lower the prices you pay to deliver content out of Amazon CloudFront. By default, Amazon CloudFront minimizes end user latency by delivering content from its entire global network of edge locations. However, because we charge more where our costs are higher, this means that you pay more to deliver your content with low latency to end-users in some locations. Price Classes let you reduce your delivery prices by excluding Amazon CloudFront’s more expensive edge locations from your Amazon CloudFront distribution. In these cases, Amazon CloudFront will deliver your content from edge locations within the locations in the price class you selected and charge you the data transfer and request pricing from the actual location where the content was delivered.

If performance is most important to you, you don’t need to do anything; your content will be delivered by our whole network of locations. However, if you wish to use another Price Class, you can configure your distribution through the AWS Management Console or via the Amazon CloudFront API. If you select a price class that does not include all locations, some of your viewers, especially those in geographic locations that are not in your price class, may experience higher latency than if your content were being served from all Amazon CloudFront locations.

Note that Amazon CloudFront may still occasionally serve requests for your content from an edge location in a location that is not included in your price class. When this occurs, you will only be charged the rates for the least expensive location in your price class.

The table below lists the groupings for each Amazon CloudFront Price Class. Learn more about how to set a Price Class in the Amazon CloudFront Developer Guide.

Price Class All	Price Class 200	Price Class 100
United States	United States	United States
Europe	Europe	Europe
Hong Kong, Korea & Singapore	Hong Kong, Korea & Singapore
Japan	Japan
India	India
South America
Australia

Reserved Capacity Pricing

Reserved Capacity gives you the option to commit to a minimum monthly usage level for 12 months or longer and in turn receive a significant discount. Reserved Capacity agreements begin at a minimum of 10 TB of data transfer per month from a single region. Customers who commit to higher usage receive additional discounts.

Interested in signing up for Reserved Capacity Pricing? Please contact us.

First 10 TB / month Next 40 TB / month Next 100 TB / month Next 250 TB / month Over 1,000 TB / month United States Europe Hong Kong, Korea & Singapore Japan India South America Australia Reserved Capacity Pricing / GB Regional Data Transfer Out Per 10,000 HTTP requests Per 10,000 HTTPS requests HTTP requests HTTPS requests Next 350 TB / month Next 524 TB / month Next 4 PB / month Over 5 PB / month

---

Common Use Cases

There are many great use cases for Amazon CloudFront, including:

A typical website generally contains a mix of static content and dynamic content. Static content includes images or style sheets; dynamic or application generated content includes elements of your site that are personalized to each viewer. Amazon CloudFront can help improve performance of your entire website in the following ways:

• Amazon CloudFront can cache static content at each edge location. This means that your popular static content (e.g., your site’s logo, navigational images, cascading style sheets, JavaScript code, etc.) will be available at a nearby edge location for the browsers to download with low latency and improved performance for viewers. Caching popular static content with Amazon CloudFront also helps you offload requests for such files from your origin sever – CloudFront serves the cached copy when available and only makes a request to your origin server if the edge location receiving the browser’s request does not have a copy of the file.

• Amazon CloudFront proxies requests for dynamic or interactive content back to your origin running in an AWS Region. Each of your end users is routed to the edge location closest to them, in terms of internet latency. Then, their requests are carried back to your origin server running in AWS on connections that Amazon monitors and optimizes for performance. Amazon CloudFront also reuses existing connections between the CloudFront edge and the origin server reducing connection setup latency for each origin request. Other connection optimizations are also applied to avoid internet bottlenecks and fully utilize available bandwidth between the edge location and the viewer. This means that Amazon CloudFront can speed-up the delivery of your dynamic content and provide your viewers with a consistent and reliable, yet personalized experience when navigating your web application.

You can use a single CloudFront distribution to deliver your entire website, including both static and dynamic or interactive content. This means that you can continue to use a single domain name (e.g., www.mysite.com) for your entire website without the need to separate your static and dynamic content. Meanwhile, you can still continue to use separate origin servers for different types of content on your website. Amazon CloudFront provides you with granular control for configuring multiple origin servers and caching properties for different URLs on your website. These performance optimizations and functionality can help speed up the download of your entire website which can help lower site abandonment. Amazon CloudFront is a good choice for software developers who wish to distribute applications, updates or other downloadable software to end users. Amazon CloudFront’s high data transfer rates speed up downloading your applications, improving the customer experience and lowering your costs . Amazon CloudFront also offers lower prices than Amazon S3 at higher usage tiers. If your application involves rich media – audio or video – that is frequently accessed, you will benefit from Amazon CloudFront’s lower data transfer prices and improved data transfer speeds. Amazon CloudFront offers multiple options for delivering your media files – both pre-recorded media and live media.

• Streaming of pre-recorded media: You can deliver your on-demand media using Adobe’s Real Time Messaging Protocol (RTMP) streaming via Amazon CloudFront. You store the original copy of your media files in Amazon S3 and use Amazon CloudFront for low-latency delivery of your media content. Amazon CloudFront integrates with Amazon S3 so you can configure media streaming by making a simple API call or with a few clicks in the AWS Management Console. You also benefit for the high throughput delivery of your media when using Amazon CloudFront, so you can deliver content in full HD quality to your viewers.

• Progressive download of on-demand media: You can store the original versions of your media content in Amazon S3 and configure an Amazon CloudFront download distribution for progressive download of your video and audio files. Popular media files are cached at the edge to help you scale and give your viewers the best possible performance.

• Delivering live events: If you need to deliver a live event – audio or video – to a global audience, Amazon CloudFront can improve performance and help offload requests to your origin infrastructure by caching your live media for a short period of time and collapsing simultaneous requests for the same media fragment to a smaller number of requests sent to the origin. In addition, Amazon CloudFront’s live HTTP solutions give you the ability to deliver your live event to viewers using different device platforms, including both Flash based and Apple iOS devices.

---

Resources

---

Detailed Description

The Amazon CloudFront Global Edge Network
To deliver content to end users with lower latency, Amazon CloudFront uses a global network of edge locations. Amazon CloudFront edge locations are located in:

United States Ashburn, VA (3) Dallas/Fort Worth, TX (2) Hayward, CA Jacksonville, FL Los Angeles, CA (2) Miami, FL New York, NY (3) Newark, NJ Palo Alto, CA San Jose, CA Seattle, WA South Bend, IN St. Louis, MO

Europe Amsterdam, The Netherlands (2) Dublin, Ireland Frankfurt, Germany (2) London, England (2) Madrid, Spain Milan, Italy Paris, France (2) Stockholm, Sweden

Asia Chennai, India Hong Kong, China (2) Mumbai, India Osaka, Japan Seoul, Korea Singapore (2) Sydney, Australia Tokyo, Japan (2)

South America São Paulo, Brazil

Amazon CloudFront Distributions

To deliver content through Amazon CloudFront, you create a distribution. There are two types of distributions you can create – Download Distributions for HTTP/HTTPS and Streaming Distributions for RTMP and its variants. Each distribution has a unique domain name that you can use in your web application. An example of an Amazon CloudFront domain name is abc123.cloudfront.net.

Download Distributions for HTTP Delivery

An Amazon CloudFront download distribution can be used to deliver your content using the HTTP or HTTPS protocols. Amazon CloudFront identifies the origin servers that hold the original version of your content by using URL matching rules you configure for each distribution (e.g., all requests that match /images/* could use your Amazon S3 as the origin, all requests matching *.php could use your Amazon EC2 instance as the origin, etc.). To work with a download distribution:

1. You place the original version of your objects in your origin servers.
2. You call the CreateDistribution API, which will return your distribution's domain name.
3. You create links to your objects in your web site or web application using the domain name.

When a viewer requests a web page or content using that domain name, Amazon CloudFront determines the best edge location to serve your content. If an edge location doesn’t have a copy of the file requested by the viewer, Amazon CloudFront will pull a copy from the origin server and hold it at the edge location so it’s available for future requests.

Content can be delivered using either the HTTP or HTTPS protocol. By default, your distribution will accept requests on either protocol. However, if you want your content delivered only over an HTTPS connection, you can configure your distributions to only accept requests that come over HTTPS. When Amazon CloudFront needs to get a file from the origin server, it will use the same protocol that was used for the end user request. For example, if an end user requests a file using HTTPS that is not already in an edge location, Amazon CloudFront will use HTTPS to get the file from the origin.

Listed below are features that relate to Amazon CloudFront download distributions:

Cache Behaviors

A cache behavior is the set of rules you configure for a given URL pattern based on file extensions, file names, or any portion of a URL path on your website (e.g., *.jpg). You can configure multiple cache behaviors for your download distribution. Amazon CloudFront will match incoming viewer requests with your list of URL patterns, and if there is a match, the service will honor the cache behavior you configure for that URL pattern. Each cache behavior can include the following Amazon CloudFront configuration values: origin server name, viewer connection protocol, minimum expiration period, query string parameters, and trusted signers for private content.

Origin Servers

You can configure one or more origin servers for your Amazon CloudFront download distribution. Origin servers can be an AWS resource, such as Amazon S3, Amazon EC2, Elastic Load Balancing, or a custom origin server outside of AWS. Amazon CloudFront will request content from each origin server by matching the URLs requested by the viewer with rules you configure for your distribution. This feature allows you the flexibility to use each AWS resource for what it’s designed for – Amazon S3 for storage, Amazon EC2 for compute, etc. – without the need to create multiple distributions and manage multiple domain names on your website. You can also continue to use origin servers you already have set-up without the need to move data or re-deploy your application code. You can learn more about support for multiple origin servers with this architecture diagram.

Viewer Connection Protocol

Content can be delivered to viewers using either the HTTP or HTTPS protocol. By default, your download distribution will accept requests on either protocol. However, if you want all your content or certain URLs delivered only over an HTTPS connection, you can configure your distribution to only accept requests that come over HTTPS for that content. You can configure this feature separately for each URL pattern in your download distribution as part of the cache behavior for that URL pattern.

Custom SSL Certificates

Custom SSL Certificate support lets you deliver content over HTTPS using your own domain name and your own SSL certificate. This gives visitors to your website lower latency and higher reliability along with the security benefits of CloudFront over an SSL connection that uses your own domain name. You can also configure CloudFront to use HTTPS connections for origin fetches so that your data is encrypted end-to-end from your origin to your end users. Configuring Custom SSL Certificate support is easy; you don’t need to learn any proprietary code or hire any consultants to configure it for you. Starting today, you can sign up for an invitation to use the Custom SSL Certificate feature by filling out the form on the AWS website. As soon as we approve your request, you can upload your SSL certificate and use the AWS Management Console to associate it with your CloudFront distributions.

Minimum Expiration Period

Amazon CloudFront uses the expiration period you set on your files (through cache control headers) to determine whether it needs to check the origin for an updated version of the file. If you expect that your files will change frequently, you can set a short expiration period on the file. Amazon CloudFront accepts expiration periods as short as 0 seconds (in which case CloudFront will revalidate each viewer request with the origin). Amazon CloudFront also honors special cache control directives such as private, no-store, etc.; these are often useful when delivering dynamic content that may not be cached at the edge. The minimum expiration period value can be configured uniquely for each of the cache behaviors you define. This allows you to maximize the cache duration for different types of content on your site by setting a lower bound on the length of time each file can remain in cache. Note that this does not change the default Amazon CloudFront behavior – if your origin does not set any cache control header, Amazon CloudFront will cache that object for a 24 hour period by default.

Query String Parameters

Query string parameters are often used to return customized content generated by a script running on the origin server. By default, Amazon CloudFront does not forward query string parameters (e.g., “?x=1&y=2”) to the origin. In addition, the query string portion of the URL is ignored when identifying a unique object in the cache. However, you can optionally configure query strings to be forwarded to the origin servers and be included in the unique identity of the cached object. This feature can be enabled separately for each unique cache behavior you configure. Query string parameters can thus help you customize your web pages for each viewer while still taking advantage of the performance and scale benefits offered by caching content at Amazon CloudFront edge locations.

HTTP Cookie Support

Amazon CloudFront supports delivery of dynamic content that is customized or personalized using HTTP cookies. To use this feature, you specify whether you want Amazon CloudFront to forward some or all of your cookies to your custom origin server. Amazon CloudFront then considers the forwarded cookie values when identifying a unique object in its cache. This way, your end users get both the benefit of content that is personalized just for them with a cookie and the performance benefits of Amazon CloudFront.

Default Root Object

You can specify a default file (e.g., index.html) that will be served for requests made for the root of your distribution without an object name specified – for instance, requests made to http://abc123.cloudfront.net/ alone, without a file name.

Object Versioning and Cache Invalidation

You have two options to update your files cached at the Amazon CloudFront edge locations. You can use object versioning to manage changes to your content. To implement object versioning, you create a unique filename in your origin server for each version of your file and use the file name corresponding to the correct version in your web pages or applications. With this technique, Amazon CloudFront caches the version of the object that you want without needing to wait for an object to expire before you can serve a newer version.

You can also remove copies of a file from all Amazon CloudFront edge locations at any time by calling the invalidation API. This feature removes the file from every Amazon CloudFront edge location regardless of the expiration period you set for that file on your origin server. If you need to remove multiple files at once, you may send a list of files (up to 1,000) in an XML document. The invalidation feature is designed to be used in unexpected circumstances, e.g., to correct an encoding error on a video you uploaded or an unanticipated update to your website’s CSS file. However, if you know beforehand that your files will change frequently, it is recommended that you use object versioning to manage updates to your files. This technique gives you more control over when your changes take effect and also lets you avoid potential charges for invalidating objects.

Access Logs

If you wish, you can also choose to receive more information about the traffic delivered or streamed by your Amazon CloudFront distribution by enabling access logs. Access logs are activity records that show you detailed information about each request made for your content. To use this feature, you must be signed up for Amazon S3 – you can do so here. You simply create or specify an Amazon S3 bucket you would like to use to store access logs. There are no additional Amazon CloudFront charges for this feature, though normal Amazon S3 charges apply to write, store and retrieve access logs using that service.

Zone Apex Support

You can use CloudFront to deliver content from the root domain, or "zone apex" of your website. For example, you can configure both http://www.example.com and http://example.com to point at the same CloudFront distribution, without the performance penalty or availability risk of managing a redirect service. To use this feature, you create an Amazon Route 53 Alias record to map the root of your domain to your CloudFront distribution.

Streaming Distributions for On-Demand Media Delivery

Amazon CloudFront lets you create “streaming distributions” to deliver your rich media content in a different way than other Amazon CloudFront distributions. Streaming distributions deliver content to end users in real time – the end-users watch the bytes as they are delivered. To do this, streaming distributions use the Real Time Messaging Protocol (RTMP) and several of its variants, instead of the HTTP or HTTPS protocols used by other Amazon CloudFront distributions. Amazon CloudFront uses Adobe’s Flash Media Server 3.5 to power its streaming distributions.

Streaming has several potential benefits for you and your end users. Streaming can provide more flexibility in playback: with streaming, it’s easy to pause, rewind, and fast-forward a media file to whatever spot is needed, without needing to worry about how much of the file has already been downloaded to the browser. You can also configure your streaming distributions to use dynamic bit-rate streaming. When enabled, this feature lets you store multiple copies of the same video, each encoded at different quality levels. Your distribution will then automatically adjust the quality of your video based on the speed of the end user’s internet connection.

Streaming also can give you more control over your content, as no file remains on the end-user’s computer when they finish watching a video. Additionally, streaming can save you money, as it only delivers portions of a media file that the end-users actually watch. In contrast, with traditional downloads, frequently the whole media file will be downloaded by the end-users, even if they only watch a portion of the file.

Streaming distributions support the wide variety of file formats that can be played using Flash. Among the supported formats are the popular FLV and MP4 media container file formats and the VP6 and H.264 video codecs.

Like all of Amazon CloudFront, streaming distributions are designed to give you high performance, reliable delivery of your content. Streaming distributions use all the edge locations in the Amazon CloudFront network, so your content is streamed from a server that is close to your end users. There are no additional charges for streaming content; you simply pay for the amount of data that you deliver at normal Amazon CloudFront rates.

After you've set up your streaming distribution, you can test your video using our video streaming diagnostic client.

HTTP Streaming of Live Media

Amazon CloudFront provides you two options to easily and cost-effectively deliver live events over HTTP (using Amazon CloudFront download distributions) to a world-wide audience using multiple devices:

• Live Streaming with Adobe Media Server: Amazon CloudFront can be used with Amazon EC2 running Adobe Media Server (AMS) for live HTTP streaming to both Flash Player and Apple iOS devices. Amazon EC2 (running FMS) must be configured as the origin for an Amazon CloudFront download distribution. We've made this simple for you by creating an AWS CloudFormation template that handles all of the provisioning and sequencing for all the AWS resources you need for this live streaming stack.Amazon CloudFront provides you the scale and flexible pay-as-you-go pricing model, while the use of HTTP protocol for streaming your live event offers your viewers easy access to your live content. Using Amazon CloudFront for live streaming also gives you full control of your AMS origin server so you can configure it to best work with the specific nature of your event. In addition, you can choose the Amazon EC2 instance type and AWS region that best meet the needs of your live event. A detailed tutorial for setting-up live HTTP streaming using Amazon CloudFront is available here.

• Live Smooth Streaming using Windows Media Services: You can also use Amazon CloudFront and Amazon EC2 running Windows Media Services for live Smooth Streaming. Smooth Streaming is Microsoft’s adaptive streaming technology used for delivering live media to Microsoft Silverlight clients. You can also use this solution to deliver your live stream in Apple’s HTTP Live Streaming (HLS) format to Apple iOS devices. We've made it simple to get started by creating a Live Smooth Streaming tutorial and an AWS CloudFormation template to automate the provisioning of AWS resources for your live streaming stack. You only pay for the AWS resources you consume, and have full control over the origin server (Amazon EC2 instance running Windows Media Services) so you can configure additional IIS Live Smooth Streaming functionality.

Amazon CloudFront and Other Amazon Web Services

Amazon CloudFront is designed to work well with other Amazon Web Services. The next few sections describe how you can use other AWS services with Amazon CloudFront to further optimize your website performance.

Using Amazon CloudFront with Amazon Route 53

Amazon Route 53 is AWS’s reliable and cost-effective Domain Name System (DNS) web service. Similar to Amazon CloudFront, Route 53 is designed to be fast and answers DNS queries with low latency by using a global network of DNS servers. You can use Amazon Route 53 to map custom domain names (including the zone apex, i.e. example.com without the www) to your Amazon CloudFront distributions using a feature called Alias record. Route 53 doesn't charge for queries to Alias records that are mapped to a CloudFront distribution.

When using Amazon Route 53 as the DNS service for your origin servers, you can configure DNS Failover to help detect an outage of your primary origin servers and redirect your end users to alternate locations where your application is operating properly. This helps add redundancy to your applications and maintain high availability for your end users served by CloudFront. You can use Route 53 to set up health checks for applications running inside or outside AWS, and you can fail over to any endpoint that you choose, regardless of location.

You can also use Route 53’s Weighted Round Robin (WRR) functionality to slowly move traffic from your origin infrastructure to Amazon CloudFront. You do this by assigning relative weights (e.g. share of traffic) to each endpoint – your origin resource and your Amazon CloudFront distribution – that you want to send viewers to. Amazon Route 53 will then use these weights to return different DNS responses to your viewers. As you become comfortable with your Amazon CloudFront configuration, you can start sending more viewers to your Amazon CloudFront distribution.

Amazon Route 53 DNS records can be configured and managed using the same AWS Management Console that you use for configuring your Amazon CloudFront distributions. This makes it easier to set up and update the CNAME or Alias records for your Amazon CloudFront distribution. With Route 53, you can also map a wildcard domain name to your CloudFront distribution using Route 53’s Alias record. Note that Route 53 does not charge for queries to Alias records that are mapped to a CloudFront distribution.

Using Amazon CloudFront with Amazon S3

Amazon S3 is a durable object store for the Internet. Amazon CloudFront is optimized to use Amazon S3 as its origin server to store the original versions of your static files.

Amazon CloudFront works well for delivery of static objects that are frequently accessed – “popular” objects. With Amazon CloudFront, copies of your popular objects are cached in a network of edge locations around the world. Because these edge locations are close to your viewers, your objects can be served more quickly than if they were served from one of Amazon S3’s central locations. This improves your viewers’ experience for frequently accessed static content: they get lower latency and faster data transfer rates. Delivering your popular objects using an Amazon CloudFront edge location can also reduce your costs, as Amazon CloudFront’s rates for data transfer are lower than Amazon S3’s at higher usage tiers.

However, when space is needed at an edge location, the Amazon CloudFront will remove less popular objects in order to make room for more popular ones. This means that your static objects that aren’t accessed frequently are less likely to remain in Amazon CloudFront’s edge locations’ caches. Thus, for less popular objects, delivery out of Amazon S3 (rather than from Amazon CloudFront) may be the better choice. Amazon S3 will provide strong distribution performance for these objects, and serving them directly from Amazon S3 saves you the cost of continually copying less popular objects from Amazon S3 to the edge locations in Amazon CloudFront.

Using Amazon CloudFront with Amazon EC2 and Elastic Load Balancing

Amazon EC2 provides compute capacity in the AWS cloud. When using Amazon EC2 as your Amazon CloudFront origin server, you get the benefit of working with the same set of tools to configure and manage the delivery of your entire web application. In addition, Amazon EC2 offers the same pay-as-you-go and pay-for-use pricing model as Amazon CloudFront does. Plus, the routes between Amazon CloudFront edge locations and Amazon EC2 data centers are constantly monitored and optimized for performance and availability. Any issues with these network routes are quickly detected and fixed or viewers are automatically routed to another Amazon monitored network route, minimizing impact to viewers of your applications.

When running multiple Amazon EC2 instances, you can also use Elastic Load Balancing to automatically distribute incoming application traffic from Amazon CloudFront edge locations. Elastic Load Balancing helps you achieve greater fault tolerance in your origin infrastructure, increasing the overall availability of your web applications delivered through Amazon CloudFront. Elastic Load Balancing can be enabled within a single Availability Zone or across multiple zones.

To achieve even higher availability and further improve the performance of Amazon CloudFront origin connections, you can run instances of your application across multiple AWS Regions with an Elastic Load Balancer endpoint in each region. Then, you can use Amazon Route 53’s Latency Based Routing (LBR) feature to route Amazon CloudFront origin requests to the AWS Region that provides the lowest possible latency to the Amazon CloudFront edge location making the request. Amazon Route 53 is integrated with Amazon CloudFront to collect latency measurements from each Amazon CloudFront edge location, resulting in optimal performance for origin fetches.

Paying for What You Use

Amazon CloudFront is designed so you don't have to pay any upfront fees or commit to how much content you’ll deliver through the network. Like other Amazon Web Services, you pay-as-you-go, and only for what you use:

• Origin server charges: If you use Amazon S3 as your origin, you pay normal Amazon S3 storage charges to store files in your bucket; these charges appear in the Amazon S3 portion of your AWS statement. Similarly, if you use Amazon EC2 as your origin, these charges will appear on the Amazon EC2 portion of your statement.

• Copying objects to edge locations: When Amazon CloudFront receives a request for an object it doesn’t already have at an edge location, it makes a standard GET request back to your origin. If that origin is in Amazon S3 or Amazon EC2, you incur the normal AWS charges for data transfer out plus Amazon S3 rates for GET requests; these charges appear in the Amazon S3 or Amazon EC2 portion of your AWS statement. Amazon CloudFront copies an object to an edge location based on the cache control headers you’ve set on that objects and if there is demand for that object at that edge location.

• Serving objects from edge locations: You incur Amazon CloudFront charges for HTTP requests, HTTPS requests and data transfer out. The data transfer charge is lower than the corresponding Amazon S3 and Amazon EC2 charges for data transfer. The Amazon CloudFront charges appear in the Amazon CloudFront portion of your AWS statement.

• Invalidating objects from edge locations: You incur Amazon CloudFront charges for each object you include in your invalidation request. Each month, you can invalidate up to 1,000 objects at no additional charge. After that quantity, a charge applies for each additional object that you request to be invalidated. In addition, for Amazon S3 origins, you will continue to incur normal Amazon S3 storage charges for these objects unless you’ve also deleted the object from your Amazon S3 bucket.

• Custom SSL Certificates: You incur a charge for each custom SSL certificate associated with one or more CloudFront distributions.

Your monthly bill from AWS separates your usage and dollar amounts by AWS service, so if you are using Amazon S3 as an origin, you’ll see some charges for Amazon S3 and some charges for Amazon CloudFront. The exact same concept also applies to Amazon EC2 or Elastic Load Balancing. Your use of Amazon S3 or Amazon EC2 related to your use of Amazon CloudFront is combined with any other Amazon S3 or Amazon EC2 usage you may have for the month.

CloudFront Limits

By default, your distributions support peak data transfer speeds of 1,000 megabits per second and peak request rates of 1,000 requests per second. If you expect more than this amount of traffic, please request a higher limit. We will add more capacity to your distributions within 2 business days.

Getting Started

The best way to understand Amazon CloudFront is to work through the Getting Started Guide, part of our Technical Documentation. Within a few minutes, you’ll be able to deliver content through the Amazon CloudFront network!

---

Intended Usage and Restrictions

Your use of this service is subject to the Amazon Web Services Customer Agreement.