CDN FAQ

Why am I getting a NO DATA error when uploading files to the CDN?

The error “No Data” when using the Java applet to upload a file greater than 20MB is due to the file size limitations we have in place on the Java applet. Use Proxy FTP to work around this limitation.

Instructions for accessing FTP credentials for CDN may be found here. Please note that users may only access the Proxy FTP from a Bare Metal Server on our network.

Can I upload files to CDN via FTP or SCP?

Absolutely, you may upload files via FTP.  Unfortunately, you may not use SCP at this time.

Access to the FTP service can be done either through the MCC FTP java applet or to the CDN directly. The login details and specific FTP server information can be found in the MCC panel, under Media Manager > FTP menu.

How many nodes does CDN use?

CDN currently delivers content across 24 nodes (and growing) around the globe, including the Americas, Europe and Asia. This provides geographic diversity and the ability to deliver content from some of the largest Internet peering points in the world. SoftLayer and its partner, Edgecast, will continue to add new nodes to CDN to expand the reach and capabilities of the service.

What file formats does CDN support?

SoftLayer’s CDN Supports Windows Media for streaming files. SoftLayer’s CDN also supports a wide array of encoding formats for downloading or caching media—including Windows Media Player, DivX, H.264, Move Media Player, Microsoft Silverlight, QuickTime, MP3, RealSystem G2, RealPlayer, Real Networks, HTML, TXT, GIF, JPG, and PDF.

How do I stream movies or other media with CDN?

To stream flash content you will need to use a flash player. Flash files that end in .swf generally have the player pre-compiled into them and aren’t considered streaming files. Flash content that can be streamed generally ends in .flv and requires a flash player. There are many open source flash players available for use that are free and can be used with very little code.

Windows media files are generally streamed in the formats of WMV of ASF files. To use them in your website you would need to “embed” them with the object.

Image files, documents and other static content that you wish to make available can be done so by simply linking to it on your web site.

How does Origin Pull work?

Origin Pull is the method of transferring data to the CDN automatically from a webserver as opposed to manually uploading the content. This method of uploading data to the CDN can be used for HTTP and on demand Windows Media content. Once the initial configuration is completed, the content will become available to the CDN by simply requesting the CDN URL associated with that content.

For example:

Edge CDN URL can point to a Bare Metal Server to obtain content. The Edge CDN URL will be http://SLXXX.cdn.softlayer.net, and the Origin URL will be http://myserver.com.

The IMG tag will tell the client to retrieve the picture.jpg image from the Edge CDN rather than directly to the Bare Metal Server. If the image is not already stored on the CDN cache, then it will go to your Origin URL, retrieve the content from the images directory, and then display it while caching the image on the CDN server. On the next request, the image will be served directly from the CDN rather than the Bare Metal Server and subsequent page loadings will be much faster.

With Origin Pull, the CDN determines if content will need to be pulled from the Bare Metal Server via the “Cache-Control” headers configured on the webserver. The CDN will honor most standard Cache-Control options such as max-age, proxy-revalidate, must-revalidate. Please note that the use of the ”private” and “no-cache” option in the Cache-Control headers will result in the CDN pulling a new version of the content for each request it receives as the headers will instruct it not to cache that content.

We recommend not setting your max-age to less than 5 to 10 minutes as this will put excessive load on your webserver and result in less optimal performance. Be aware that if content on the webserver has been updated, each POP will continue to serve the old cached version until that cache is purged or the cache on the POP expires. If no max-age header is set, the default max-age of 24 hours will be used.

What is CDN HTTP Small Object?

HTTP Small Object is a method of caching objects on our Content Delivery Network (CDN). This method honors all HTTP 1.1 cache control rules; however, HTTP Small Object caches objects up to 300KB in size and is not enabled for streaming. Objects cached using HTTP Small Object may only be reached using their HTTP or HTTPS URL. Objects cached on servers devoted to HTTP Small Object are retrieved quicker than our traditional CDN offering - they are stored in the server's memory as opposed to being stored on a disk, making them more readily accessible by our systems.

How do I know if I should use HTTP Small for my CDN needs?

Most users primarily utilize our standard (HTTP Large Object) CDN offering. Files are easily cached on the standard platform and there are no size limitations to objects stored and delivered with the standard offering. HTTP Small Object should be used when speed is a necessity, the file in question is 300KB or less in size, and the functionality available in our standard CDN offering is not required for delivery of the file (i.e. streaming content). If the file is unable to meet these parameters, use our standard CDN option.

How do I stream movies or other media?

There are a variety of methods to stream content via the CDN:


HTTP PROGRESSIVE
HTTP Progressive download uses the HTTP protocol to stream archived media content. As a result, it cannot take advantage of the security features that are available with the RTMP protocol, such as encryption and SWF verification. Additionally, the entire video is downloaded to a user’s computer. As a result of all of these factors, HTTP Progressive Download is more susceptible to piracy than either Live StreamCast or On-Demand Streaming. This method can be used with Flash video or Windows Media files.
 

WINDOWS LIVE STREAMCAST
This method allows you to distribute a live video stream to the CDN and then to browser clients. You can set up the stream to be push or pull, meaning that either the server will “push” the video stream to the CDN for download, or the CDN will “pull” the content from your server when requests for the stream are needed.


WINDOWS ON DEMAND STREAMING
The first step in this process is for a client to request on-demand content from our CDN. This type of request occurs when a media player points to a stream using a player URL that references on-demand content stored on a CDN origin server. (This is not your server, but rather a server on the CDN that has the media uploaded to it previously.)
 

When a client requests on-demand content, a check is performed to find out whether the requested content has already been cached at the POP closest to your client. If it is already there, then the on-demand content is immediately served up to that client. This allows those clients to enjoy even faster on-demand streaming. If the requested Windows media content is not found, the second step for serving on-demand content is for the POP closest to the client to retrieve the requested Windows media content from the CDN origin server.
 

If the requested on-demand content has not been cached, then it will be delivered from the CDN origin server to the POP closest to the client. The stream will be delivered to this POP by leveraging our worldwide network. This allows us to bypass traditional Internet communication routes, which ensures the efficient transmission of your Windows media content and reduced bandwidth load on your server. By default, on-demand content will be cached on that POP. This allows future requests from the region served by this POP to bypass data retrieval from the CDN origin server.

Image files, documents and other static content that you wish to make available can be done so by simply linking to it on your web site. For example, if you wish to put images on the CDN you would use the following code to display it on your site:
/img.jpg alt=”my image” /> This would direct users’ browsers to download the image from the CDN as opposed to directly from your servers.