This disclosure relates in general to content delivery networks (CDNs) and, but not by way of limitation, to delivery of content more effectively.
Content delivery networks (CDNs) are used by originators of content to offload delivery of content objects. CDNs distribute edge servers throughout the Internet that host and/or cache content for content originators as a service. Only the largest content originators distribute content objects in an effective manner. A smaller content originator may overload their servers provide poor quality of service (QoS) or worse without reliance on a CDN.
CDNs typically service a large number of end user systems requesting content. If an edge server is assigned a particular delivery, it typically will locate the content object and load it locally as it is delivered. Some of these content objects are especially large. Distribution of large content objects is costly in terms of resources. Often, large content objects are only partially delivered to an end user before the download or stream is terminated or paused.
In one embodiment, the present disclosure provides a system and method for delivering content objects over the Internet to an end user system with a content delivery network (CDN). The system and method allow for dynamically storing and distributing a portion of content streams. When a content object is requested by an end user media player, the request is assigned to an edge server within the CDN. Characteristics of the content object are used to determine the portion of the content object where the portion is less than all of the requested content. The portion of content object is then retrieved from the content and is stored within the CDN. The portion of requested content is streamed to the end user media player. Ultimately, the whole content is streamed to the end user media player if the remainder of content is requested by the end user media player.
In an embodiment, the present disclosure provide a method for streaming content object over the Internet to an end user system with a CDN, which distributes a vignette of the content object to the end user system. A request to stream a content object to the end user system is received. The request is assigned to an edge server within the CDN. A portion of the content object is determined based, at least in part, on the characteristics of the content object. The portion is less than all of content object. The content object comprises a portion and a remainder. The portion of the content object is retrieved from a remote location. The portion of the content object is stored such that the portion is accessible to the edge server without storing the remainder unless subsequently requested. The portion of the content object is streamed to the end user system.
In another embodiment, the present disclosure provide a CDN for streaming content over the Internet to an end user system, the CDN comprising a content object request function, an edge server selection function, a stream-request function, and a streaming function, etc. The content object request function receives a request for streaming content object to the end user system. The edge server selection function assigns the request to an edge server for streaming content to the end user system. The stream-request function: determines the portion of the content object based, at least in part, on the characteristics of the content object; retrieves the portion of the content object from a remote location; and stores the portion of the content object such that the portion is accessible to the edge server without storing the remainder unless requested. The portion is less than all of content object. The content object comprises a portion and a remainder. The streaming function streams the portion of the content object to the end user system.
In yet another embodiment, the present disclosure provide a method for delivering at least a portion of a content object over the Internet to an end user system with a CDN, which distributes the portion of the content object to the end user system. A request to deliver a content object to the end user system is received. The request is assigned to an edge server within the CDN. A portion of the content object is determined based, at least in part, on the characteristics of the content object. The portion is less than all of content object. The content object comprises a portion and a remainder. The portion of the content object is retrieved from a remote location. The portion of the content object is stored such that the portion is accessible to the edge server without storing the remainder unless subsequently requested. The portion of the content object is delivered to the end user system.
Further areas of applicability of the present disclosure will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating various embodiments, are intended for purposes of illustration only and are not intended to necessarily limit the scope of the disclosure.
The present disclosure is described in conjunction with the appended figures:
In the appended figures, similar components and/or features may-have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.
The ensuing description provides preferred exemplary embodiment(s) only, and is not intended to limit the scope, applicability or configuration of the disclosure. Rather, the ensuing description of the preferred exemplary embodiment(s) will provide those skilled in the art with an enabling description for implementing a preferred exemplary embodiment. It being understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope as set forth in the appended claims.
Referring first to
In this embodiment, the content distribution system 100 determines a portion of the content objects and distributes the portion of the content objects to an end user system 102. In this way, the portion of the requested contents are dynamically cached within the CDN 110 to improve the quality of service (QoS) without replicating the whole content object, unless subsequently requested by the end user 128. A content object is any content file or content stream and could include, for example, video, pictures, data, audio, software, and/or text. The content object could be live, delayed or stored. Throughout the specification, references may be made to a content object, content, content stream and/or content file, but it is to be understood that those terms could be used interchangeably wherever they may appear.
Many content providers 108 use a CDN 110 to deliver the content objects over the Internet 104 to end users 128. The CDN 110 includes a number of points of presence (POPs) 120, which are geographically distributed through the content distribution system 100 to deliver content. Various embodiments may have any number of POPs 120 within the CDN 110 that are generally distributed in various locations around the Internet 104 that are proximate to end user systems 102. A wide area network (WAN) 114 or other backbone may couple the POPs 120 with each other and also couple the POPs 120 with other parts of the CDN 110.
When an end user 128 requests a web page through its respective end user system 102, the request for the web page is passed either directly or indirectly via the Internet 104 to the content originator 106. The content originator 106 is the source or re-distributor of content objects. The content site 116 is an Internet web site accessible by the end user system 102. In one embodiment, the content site 116 could be a web site where the content is viewable with a web browser. In other embodiments, the content site 116 could be accessible with application software other than a web browser. The content provider 108 redirects content requests to a CDN 110 after they are made or formulates the delivery path by embedding the delivery path into the URLs for a web page. In any event, the request for content is handed over to the CDN 110 in this embodiment.
Once the request for content object is passed to the CDN 110, it will be associated with a particular POP 120 within the CDN 110. The particular POP 120 may retrieve the portion of the content object from the content provider 108. Alternatively, the content provider 108 may directly provide the content object to the CDN 110 and its associated POPs 120, i.e., in advance of the first request. In this embodiment, the content objects are provided to the CDN 110 and stored in one or more CDN servers such that the portion of the requested content may be served from the CDN 110. The origin server 112 holds one copy of each content object for the content originator 106. Periodically, the content of the origin server 112 may be reconciled with the CDN 110 through a cache, hosting and/or pre-population algorithm.
Once the portion of the content object is retrieved, it will be stored within the particular POP 120 and will be served from that POP to the end user system 102. The end user system 102 receives the content object and processes it for the end user 128. The end user system 102 could be a personal computer, media player, handheld computer, Internet appliance, phone, IPTV set top, streaming radio or any other device that receives and plays content objects. In some embodiments, a number of the end user systems 102 could be networked together. Although this embodiment only shows a single content originator 106 and a single CDN 110, it is to be understood that there could be many of each in various embodiments.
Referring next to the
The particular POP 120 receives the request for content object through the content request interface 220 and distributes the request to the edge server selection function 224. The edge server selection function 224 assigns the request for content to an edge server 230 to stream the portion of the content object to the end user system 102. The edge server selection function 224 selects the edge server 230 from a group of edge servers 230 in the POP 120. There are a number of mechanisms used by the edge server selection function 224 such as through the domain name service (DNS) resolution, by redirecting the request for a content object or other known mechanisms.
Various parameters may be taken into account by the edge server selection function 224 for choosing of the edge server 230. Examples of parameters influencing selection of a particular edge server may include content object characteristics, servers assignment to a particular content provider, adequate quality of service (QoS), performance metrics, capabilities of the CDN edge server 230, and/or routing efficiency between the edge server 230 and the end user system 102. Embodiments could have any number of edge servers 230 within each POP 120 of the CDN 110. A content database 232 stores content objects or portions thereof along with information that is relevant to the characteristics of the content object. Examples of content object characteristics may include storage space available on the edge server, size of the content object and encoded format of the content object.
Once the request for content is assigned to the selected edge server 230, the content object characteristics from the content database 232, are used to determine a portion of the content object. The stream-request function 240 gathers the content object characteristics and determines the portion of the content to request initially. In this embodiment, the stream-request function 240 is used by a number of edge servers 230, but in other embodiments each edge server 230 could perform the stream-request function 240 for the streams requested from the particular edge server 230.
As will be described further below in various embodiments, the step of determining the portion of the content object to cache initially is performed by the stream-request function 240, which may use various algorithms. After determining the portion of the requested content, the stream-request function 240 retrieves the portion of the content object from a remote location if not stored already in one of the content databases 232. The remote location may be an origin server 112 or another CDN server in the same or different POP 120. The portion of the requested content is then stored on the content database 232 such that the stored portion of the content object is accessible to the selected edge server 230.
The streaming function 228 streams the portion of the requested content to the end user system 102. In this embodiment, the streaming function 228 is shared by a number of edge servers 230, but in other embodiments, each edge server 230 includes its own streaming function 228. The streaming function 228, stream-request function 240, edge server selection function 224, and content request interface 220 could be implemented in one or more servers, network appliances and/or switches.
Referring next to
Once the request is assigned to the edge server 230, processing continues to block 306 where the stream-request function 240 determines a portion or vignette from the content object for a sample vignette. The sample vignette may be a video or audio clip in some embodiments. In one embodiment, the portion of the requested content may have a fixed length that are retrieved from different parts of the content object. In an alternative embodiment, the portion of the content object may vary in length. This embodiment determines the length of the portion according to the statistics information, which is tracked over time to provide an estimate of the length of the portion. In yet another embodiment, the portion of the content object may include a number of portions from the content object. Other embodiments may determine the portion of the content object based upon a determination of what size will provide an adequate quality of service (QoS) during download.
After determining the portion of the requested content to cache in the content database 232, the stream-request function 240 retrieves the portion of the content object at block 308. In one embodiment, the portion of the content object may be retrieved from an origin server 112. Other embodiments may retrieve the portion of the content from another CDN server in the same or a different POP 120. Once the portion of the content object is retrieved, processing continues to block 310 where the stream-request function 240 stores the portion of the requested content in the content database 232 and updates other information in the content database 232. The stored portion of the content is accessible to the edge server 230 and other edge servers 230 distributed throughout the CDN 110. The processing then goes to block 312 where the streaming function 228 streams the portion of the requested content to the end user system 102 that requested the portion back in block 302.
A determination is made, at block 314 as to whether the remainder of the content is subsequently requested by the end user 128. If the remainder of the content is requested, processing flows from block 314 to block 316 where the stream-request function 240 retrieves and stores the whole content object or more of the content object while the streaming function 228 streams the requested content to the end user system 102. The request for more of the content object could be implicit, for example, the end user 128 could watch the content object beyond the portion. If the remainder of the content is not requested, processing goes back to block 302 for receiving the next request.
Referring next to
Some embodiments could only stall the fetch of the portion in some circumstances. A determination could be made as to whether the portion is likely to be requested by another in the near term. Popularity could be used to anticipate future requests or other factors could be used in the prediction. If future requests are anticipated, the portion could be completely fetched regardless of whether the stream stopped to a particular end user. On the other hand, for a portion unlikely to be used, a stall would stop fetching the portion.
Referring next to
In block 309, it is determined if streaming continues or if the end user stalled in the playback or switched to a different bitrate, for example. Where requests for the stream stop, processing goes from block 309 to block 302. Where streaming continues processing goes from block 309 to 311 to determine if the entire portion is received. Upon receipt of the entire portion, processing continues to block 314. Where more of the portion is missing, processing loops back to block 307 to obtain the next chunk.
With reference to
Once the storage space for the portion is determined, the process continues to block 406 where the start of portion in the requested content object is identified. The stream-request function 240 is used to identify the start of the portion of the content object. The start of the portion coincides with the start of the content object in this embodiment. However, the start of the portion may occur anywhere within the content object in various embodiments.
Different methods and algorithms are used to identify the start portion within the content in block 406. In some embodiments, the content object is playback time encoded within the content object to allow determining the start of the portion by analysis of the playback time at various times throughout the content object. In an alternative embodiment, the start portion may be identified by decoding the encoded content up until the start of the portion. After identifying the start portion, processing flows to block 408 where the end of portion is identified using start of the portion location and moving the time length to find the end of the portion.
Referring next to
With reference to
Once the characteristics of the content object are retrieved, processing continues to block 604 where the stream-request function 240 determines the number of chapters in the requested content. In this embodiment, a separate control stream or metadata is provided for the content object such that the CDN 110 determines the timing information necessary to know when one chapter ends and another begins. Although chapters are one way to define the different portions that could be gathered for a content object, there are other ways to define the portions such as a small clip every ten minutes or some other time increment.
The time segment for each chapter is then determined at block 606 and the processing flows to block 608 where the stream-request function 240 selects the first chapter. This embodiment determines the storage space per time segment and identifies the start and end portion of the content for each chapter at blocks 610, 612 and 614. The portion of the content object, for each chapter, is then retrieved and stored at blocks 616 and 618.
A determination is made, at block 620 as to whether the last chapter of the content is reached or selected. If the last chapter is not reached, processing flows from block 620 to block 608 where the next chapter in the content is available for selection. The processing then continues through the blocks 610-620 until the last chapter is reached or selected. If the last chapter is reached, processing ends for the content object. Although this embodiment gathers all the portions up front, other embodiments could gather the various portions as playback or trick-play gets close to the portion.
Referring next to
In this embodiment, the QoS buffer time is determined in block 706. The time or size of the QoS buffer is determined based, at least in part, on the time consumed streaming the whole content according to the characteristics of the requested content versus the speed of the network connection. Once the QoS buffer is determined, processing continues to block 707 where the QoS buffer is added to the portion to extend the end point of the expanded portion. Processing flows to block 708 where the storage space or length is determined for the expanded portion. The start and end of the expanded portion are respectively identified at blocks 406 and 408.
Some embodiments could determine how likely the content object will be requested by others. If the content is unlikely to be requested ever again, the portion could be smaller than if the content is likely to be requested soon thereafter. A popularity metric could be maintained by the CDN and/or content originator that would be one factor in determining the size of the portion.
In some embodiments, the size of the content object is small. It may be that the playback length is small and/or that the bitrate is small. In any event, smaller content objects do not heavily tax the CDN. In those embodiments, content objects below a certain threshold in size could forgo the process of determining a portion for placement in the edge server before needed. Since not resource intensive, the smaller content objects would be handled in a traditional manner.
A number of variations and modifications of the disclosed embodiments can also be used. For example, some of the above embodiments calculate the vignette size by playback times, but other embodiments could choose a portion of the content object by its size. For example, the first byte, 5 MB, 10 MB or 20 MB could be stored. Some embodiments could make the vignette sticky in a cache of the edge server or otherwise prevent the vignette from purging normally from the cache. Later requests for the content object would have the vignette immediately available by avoiding purge from the cache.
The amount to initially store could be derived by estimating the maximum storage that would be necessary to store a particular time segment. For example, at the maximum bitrate for content objects for a particular content originator, 10 MB may always be able to store the first two minutes. To simplify things, the first 10 MB could be stored upon request rather than determining particular time values.
While the principles of the disclosure have been described above in connection with specific apparatuses and methods, it is to be clearly understood that this description is made only by way of example and not as limitation on the scope of the disclosure.
This application claims the benefit of U.S. Provisional Application Ser. No. 61/098,530 filed on Sep. 19, 2008, which is hereby expressly incorporated by reference in its entirety for all purposes.
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