Patent Application
20140229523
The present invention relates to a content delivery system, a control apparatus, and a content delivery method. In particular, it relates to: a content delivery system in which a content including a moving image, a still image, audio, software, an application, or the like is cached on a mobile network and the content is delivered to a terminal such as a mobile phone, a smartphone, a PC (personal computer), or a game machine; a control apparatus for the content delivery system; and a content delivery method.
With increase in speed and capacity of mobile networks, content delivery is becoming increasingly common. In content delivery, contents are delivered to various terminals such as mobile terminals via mobile networks. It is predicted that the speed and capacity of mobile networks will be increased further through techniques such as LTE (Long Term Evolution) and EPC (Evolved Packet Core).
For example, PTL (Patent Literature) 1 discloses a technique relating to a content delivery system. According to PTL 1, the content delivery system is provided with cache apparatuses so as to reduce access time and to prevent network congestion.
The entire disclosure of the above PTL is incorporated herein by reference thereto. The following analysis has been made by the present inventor.
It is predicted that the amount of data system traffic on mobile networks will be increased several dozen times by 2013 and that video contents will account for most of the data system traffic. In addition, as smartphones spread rapidly and terminal capabilities improve further, sizes of video contents are increasing more and more. Accordingly, it is predicted that hi-definition, large-capacity contents will also be delivered on mobile networks in the near future.
However, in a conventional content delivery system, when contents on the Internet are delivered via a mobile network, all the content requests from terminals are transmitted to a delivery server apparatus on the Internet via packet forwarding apparatuses. In addition, the delivery server apparatus delivers the contents to all the terminals via the packet forwarding apparatuses.
However, such configuration has the following problems.
When terminals access a popular content in a concentrated manner, traffic to the delivery server apparatus via the mobile network is concentrated. In addition, network load in an area where many accesses are made could surge locally. In such cases, until data reaches the delivery server apparatus, the data is congested in the mobile network. If such network congestion occurs, delay or packet loss is caused, deteriorating QoE (Quality of Experience) such as by freeze-up or deterioration of an image or interruption of voice on the terminal side. These problems can be more significant if more terminals are used and larger-capacity contents are delivered.
Furthermore, for example, when a new content is introduced and popularity of a certain content is suddenly changed, traffic becomes more concentrated. As a result, it will be difficult to avoid further concentration of the traffic to the delivery server apparatus and to avoid network congestion, counted as a problem.
Thus, there is a demand for a technique to avoid congestion on a mobile network even when contents are delivered via the mobile network and a certain content is accessed in a concentrated manner.
According to a first aspect of the present invention, there is provided a content delivery system comprising:
a packet forwarding apparatus(es) that forwards a plurality of contents delivered from a delivery server apparatus on the Internet;
a plurality of cache servers that are arranged for or connected to the packet forwarding apparatus(es) and that temporarily store at least some of the plurality of contents; and
a control apparatus that collects an access frequency of each of the at least some of the contents from the plurality of cache servers, arranges contents whose access frequency is equal to or higher than a predetermined threshold in the plurality of cache servers in accordance with a predetermined arrangement, and arranges the other contents in the plurality of cache servers in accordance with access frequencies of the other contents.
According to a second aspect of the present invention, there is provided a control apparatus, which is used in a content delivery system including a packet forwarding apparatus(es) that forwards a plurality of contents delivered from a delivery server apparatus on the Internet and a plurality of cache servers that are arranged for or connected to the packet forwarding apparatus(es) and that temporarily store at least some of the plurality of contents and which controls the plurality of cache servers;
wherein the control apparatus collects an access frequency of each of the at least some of the contents from the plurality of cache servers, arranges contents whose access frequency is equal to or higher than a predetermined threshold in the plurality of cache servers in accordance with a predetermined arrangement, and arranges the other contents in the plurality of cache servers in accordance with access frequencies of the other contents.
According to a third aspect of the present invention, there is provided a content delivery method, which is used in a content delivery system including a packet forwarding apparatus(es) that forwards a plurality of contents delivered from a delivery server apparatus on the Internet and a plurality of cache servers that are arranged for or connected to the packet forwarding apparatus(es) and that temporarily store at least some of the plurality of contents, the content delivery method comprising:
by a control apparatus controlling the plurality of cache servers, collecting an access frequency of each of the at least some of the contents from the plurality of cache servers;
arranging contents whose access frequency is equal to or higher than a predetermined threshold in the plurality of cache servers in accordance with a predetermined arrangement; and
arranging the other contents in the plurality of cache servers in accordance with access frequencies of the other contents.
The present invention provides the following advantage, but not restricted thereto. With the content delivery system, the control apparatus, and the content delivery method according the present invention, it is possible to avoid congestion on a mobile network even when contents are delivered via the mobile network and a certain content is accessed in a concentrated manner.
In the present disclosure, there are various possible modes, which include the following, but not restricted thereto. First, an outline of the present invention will be described. The reference characters in the following outline are merely used as examples to facilitate understanding of the present invention. Therefore, the reference characters are not intended to limit the present invention to the illustrated modes.
As illustrated in
It is preferable that the control apparatus (160) generate copies of each content whose access frequency is lower than the predetermined threshold, the number of copies being determined based on a corresponding access frequency, and arrange the copies in the plurality of cache servers (110_1 to 110_N). In addition, it is preferable that the control apparatus (160) arrange the contents whose access frequency is lower than the predetermined threshold in a cache server(s) whose load is equal to or less than a predetermined threshold among the plurality of cache servers (110_1 to 110_N). In addition, the control apparatus (160) may arrange the contents whose access frequency is equal to or higher than the predetermined threshold in all the plurality of cache servers (110_1 to 110_N).
When a content delivery request is made by a terminal (for example, the mobile terminal 170), the control apparatus (160) selects a cache server storing the content from the plurality of cache servers (110_1 to 110_N) and instructs the selected cache server to deliver the content. In addition, it is preferable that, when plural cache servers among the plurality of cache servers (110_1 to 110_N) store the content requested by a terminal (170), the control apparatus (160) select a cache server with minimum load from the plural cache servers and instruct the cache server to deliver the content. In addition, it is preferable that, when a content delivery request is made by a terminal (170) and none of the plurality of cache servers (110_1 to 110_N) stores the content, the control apparatus (160) instruct a cache server selected from the plurality of cache servers (110_1 to 110_N) to acquire the content from the delivery server apparatus (120) and to deliver the content.
In addition, as illustrated in
In the content delivery system according to the present invention, the control apparatus (160) refers to an access frequency of each of the contents accumulated in the cache servers (110_1 to 110_N) and arranges contents whose access frequency is high in a plurality of cache servers in accordance with a predetermined arrangement. The control apparatus (160) arranges the other contents in a plurality of cache servers on the basis of the respective access frequencies. Thus, with the content delivery system according to the present invention, for example, contents whose access frequency is relatively high can be distributed and arranged in many cache servers and contents whose access frequency is relatively low can be arranged in fewer cache servers on the basis of the respective access frequencies. According to the content delivery system, it is possible to avoid congestion on a mobile network even when contents are delivered via the mobile network and a certain content is accessed in a concentrated manner.
According to the present invention, the following modes are possible.
See the content delivery system according to the above first aspect.
The control apparatus may generate copies of each content whose access frequency is lower than the predetermined threshold, the number of copies being determined based on a corresponding access frequency, and arrange the copies in the plurality of cache servers.
The control apparatus may arrange the contents whose access frequency is lower than the predetermined threshold in a cache server(s) whose load is equal to or less than a predetermined threshold among the plurality of cache servers.
The control apparatus may arrange the contents whose access frequency is equal to or higher than the predetermined threshold in all the plurality of cache servers.
When a content delivery request is made by a terminal, the control apparatus may select a cache server storing the content from the plurality of cache servers and instruct the selected cache server to deliver the content.
When plural cache servers among the plurality of cache servers store the content requested by the terminal, the control apparatus may select a cache server with minimum load from the plural cache servers and instruct the cache server to deliver the content.
When a content delivery request is made by a terminal and none of the plurality of cache servers stores the content, the control apparatus may instruct a cache server selected from the plurality of cache servers to acquire the content from the delivery server apparatus and to deliver the content.
When a content delivery request is made by a terminal, the control apparatus may instruct a cache server that is not storing the content among the plurality of cache servers to acquire the content from a cache server storing the content among the plurality of cache servers and to deliver the content.
The packet forwarding apparatus(es) may be an SGSN apparatus, a GGSN apparatus, or an SGSN/GGSN apparatus on a mobile network or an S-GW (Serving Gateway) apparatus, a P-GW (Packet data network Gateway) apparatus, or an S/P-GW apparatus on a mobile LTE (Long Term Evolution)/EPC (Evolved Packet Core) network.
The plurality of contents may include at least one of a moving image, a still image, voice, audio, software, an application, and data.
See the control apparatus according to the above second aspect.
The control apparatus may generate copies of each content whose access frequency is lower than the predetermined threshold, the number of copies being determined based on a corresponding access frequency, and arrange the copies in the plurality of cache servers.
The control apparatus may arrange the contents whose access frequency is lower than the predetermined threshold in a cache server(s) whose load is equal to or less than a predetermined threshold among the plurality of cache servers.
The control apparatus may arrange the contents whose access frequency is equal to or higher than the predetermined threshold in all the plurality of cache servers.
When a content delivery request is made by a terminal, the control apparatus may select a cache server storing the content from the plurality of cache servers and instruct the selected cache server to deliver the content.
When plural cache servers among the plurality of cache servers store the content requested by the terminal, the control apparatus may select a cache server with minimum load from the plural cache servers and instruct the cache server to deliver the content.
When a content delivery request is made by a terminal and none of the plurality of cache servers stores the content, the control apparatus may instruct a cache server selected from the plurality of cache servers to acquire the content from the delivery server and to deliver the content.
When a content delivery request is made by a terminal, the control apparatus may instruct a cache server that is not storing the content among the plurality of cache servers to acquire the content from a cache server storing the content among the plurality of cache servers and to deliver the content.
See the content delivery method according to the above third aspect.
There is provided a program, which is used in a content delivery system including a packet forwarding apparatus(es) that forwards a plurality of contents delivered from a delivery server apparatus on the Internet and a plurality of cache servers that are arranged for or connected to the packet forwarding apparatus(es) and that temporarily store at least some of the plurality of contents and which causes a computer provided for a control apparatus controlling the plurality of cache servers to execute: collecting an access frequency of each of the at least some of the contents from the plurality of cache servers;
arranging contents whose access frequency is equal to or higher than a predetermined threshold in the plurality of cache servers in accordance with a predetermined arrangement; and
arranging the other contents in the plurality of cache servers in accordance with access frequencies of the other contents.
The program can be provided as a program product recorded in a non-transient computer-readable recording medium.
Next, configurations and operations of content delivery systems according to exemplary embodiments will be described in detail with reference to
A content delivery system according to a first exemplary embodiment will be described with reference to the drawings.
In
The SGSN/GGSN apparatuses 190_1 to 190_N (N≧2) are arranged on the mobile network 150. The RNC apparatuses 195_1 to 195_L (L≧2) are connected to the SGSN/GGSN apparatus 190_1. Likewise, the RNC apparatuses 197_1 to 197_L are connected to the SGSN/GGSN apparatus 190_N. While the L RNC apparatuses are also connected to the SGSN/GGSN apparatus 190_2, illustration thereof is omitted in
In
The mobile terminal 170 transmits a delivery connection request message including the URL (Uniform Resource Locator) of a requested content. Next, a base station apparatus (in
The RNC apparatus 195_L receives the connection request message from the base station apparatus stores the connection request message, the IP (Internet Protocol) address of the delivery server apparatus 120, the IP address of the mobile terminal 170, and the like in a payload portion of a GTP (GPRS Tunneling Protocol) packet, and forwards the GTP packet to the SGSN/GGSN apparatus 190_1 managing the RNC apparatuses 195_1 to 195_L.
Next, the SGSN/GGSN apparatus 190_1 receives the GTP packet.
The cache server 110_1 is connected to a Gi interface of a GGSN function unit of the SGSN/GGSN apparatus 190_1. Likewise, the cache server 110_N is connected to a Gi interface of a GGSN function unit of the SGSN/GGSN apparatus 190_N.
The cache servers 110_1 to 110_N are connected to the control apparatus 160. The control apparatus 160 instructs two or more cache servers to arrange contents whose access frequency is higher than a threshold Th1 in a predetermined arrangement. In contrast, for some or all of the contents whose access frequency is lower than the threshold Th1, the control apparatus 160 calculates an optimum arrangement in the cache servers 110_1 to 110_N and transmits content arrangement instructions to the cache servers based on the calculation result.
If a cache server receives a content arrangement instruction from the control apparatus 160, the cache server accesses the specified content in the delivery server apparatus 120 via the corresponding SGSN/GGSN apparatus and accumulates the content in the cache server. In addition, when requested by the mobile terminal 170, the cache server delivers the requested content to the mobile terminal 170.
Next, a configuration of the control apparatus 160 will be described with reference to the drawings.
The control signal transmission and reception unit 161 receives access frequency information about each content from each of the cache servers 110_1 to 110_N. In addition, the control signal transmission and reception unit 161 receives load information from each cache server. The control signal transmission and reception unit 161 outputs the access frequency information to the access measurement unit 184 and outputs the load information to the content arrangement calculation unit 185 and the cache server selection unit 187.
The access measurement unit 184 collects access number information about each content from each cache server at predetermined time intervals or when a predetermined condition is satisfied. The access measurement unit 184 adds up and sorts these items of access number information by the number of cache servers, to aggregate an access frequency per content for all of the cache servers. In addition, the access measurement unit 184 outputs such access frequency per content to the content arrangement calculation unit 185.
The content arrangement calculation unit 185 receives the load information about each cache server from the control signal transmission and reception unit 161 and receives the access frequency per content from the access measurement unit 184.
A configuration of the content arrangement calculation unit 185 will be described with reference to the drawings.
The threshold calculation unit 204 receives the access frequency per content from the access measurement unit 184 at predetermined time intervals or when a request is made and calculates the threshold Th1 for an access frequency. For example, the threshold calculation unit 204 may calculate an average access frequency and an access distribution of a content and set a threshold to the top Y %. The threshold calculation unit 204 outputs the threshold Th1 to the determination unit 201.
The determination unit 201 receives an access frequency per content from the access measurement unit 184 at predetermined time intervals or when a request is made. The determination unit 201 also receives the threshold Th1 from the threshold calculation unit 204. The determination unit 201 determines contents whose access frequency exceeds the threshold Th1 and outputs information about the contents to the arrangement instruction unit 203.
For the contents whose access frequency exceeds the threshold Th1, the arrangement instruction unit 203 gives an instruction about a predetermined arrangement. As to the predetermined arrangement, the arrangement instruction unit 203 may give an instruction so that the contents whose access frequency exceeds the predetermined threshold Th1 are arranged in all the cache servers 110_1 to 110_N. However, the arrangement method is not limited to such method.
In addition, the determination unit 201 outputs information about the contents whose access frequency is lower than the predetermined threshold Th1 and access frequency information about each of the contents to the calculation unit 202.
The calculation unit 202 receives the information about the contents whose access frequency is lower than the predetermined threshold Th1 and the access frequency information about each of the contents from the determination unit 201. In addition, the calculation unit 202 receives load information about each cache server from the control signal transmission and reception unit 161. The calculation unit 202 determines which cache servers need to accumulate necessary contents, for example, in view of coordination among the cache servers as will be described below.
The calculation unit 202 sorts the contents in descending order of access frequency and creates Kj copies of each of the contents in descending order of access frequency (0≦Kj≦M). j represents a content number, and M is an integer that satisfies 0<M≦N. In addition, N is the number of cache servers.
The calculation unit 202 may vary this value Kj, depending on the content. For example, more copies are created for contents whose access frequency is higher and fewer copies are created for contents whose access frequency is lower. For example, the calculation unit 202 may set M as Kj for a content with a high access frequency and set smaller values M−1, M−2, and so on for the other contents with lower access frequencies, sequentially. Alternatively, the calculation unit 202 may set Kj=1 for a content with a low access frequency and Kj=0 when a content exceeds the capacity of a cache.
It is preferable that the calculation unit 202 arrange the Kj copies of a content in Kj cache servers, respectively. In addition, it is preferable that, as the Kj cache servers, the calculation unit 202 select cache servers in descending order of access frequency of the content in question. Alternatively, the calculation unit 202 may randomly select the Kj cache servers.
When determining arrangement of contents in a cache server, the calculation unit 202 uses formula (1) to calculate the total size of the contents that can be accumulated in the cache server. If the total size exceeds the capacity of the cache server, the calculation unit 202 does not arrange any more contents.
In formula (1), Si represents the total size (in bytes) of an i-th cache server and Sik represents the size (in bytes) of a k-th content arranged in the i-th cache server.
In order to reduce throughput of the calculation unit 202 for determining arrangement of the contents, the following configurations may be used. First, the calculation unit 202 may arrange contents only in a plurality of predetermined cache servers. Second, the calculation unit 202 may arrange contents only in cache servers satisfying a predetermined condition. For example, the calculation unit 202 arranges contents only in cache servers that have transmitted load information indicating a load value equal to or lower than a predetermined threshold. Third, from the contents whose access frequency is less than the threshold Th1, the calculation unit 202 may extract only predetermined P contents in descending order of access frequency and arrange the extracted P contents.
After receiving an output from the calculation unit 202, the arrangement instruction unit 203 instructs each cache server, which has been determined as an arrangement target by the calculation unit 202, to acquire and accumulate a copy(ies) of an arrangement target content via the control signal transmission and reception unit 161 in
The arrangement instruction unit 203 may instruct the target cache server(s) to acquire a copy(ies) of the arrangement target content from the delivery server apparatus 120. Alternatively, if a certain cache server does not have a content and if a neighboring cache server has the content, the arrangement instruction unit 203 may instructs the certain cache server to acquire a copy(ies) of the content from the neighboring cache server. In this case, information about which cache server has the necessary content is read from the content map creation and accumulation unit 167 in
In addition, for contents that have not been determined by the calculation unit 202 as arrangement calculation targets, the arrangement instruction unit 203 may instruct the cache servers to perform the following processing. Namely, when receiving a request for a content from the mobile terminal 170, the arrangement instruction unit 203 may instruct a cache server to read the content from the delivery server apparatus 120, instruct the temporary content accumulation unit 113 of a cache server to cache the content, and instruct the cache server to deliver the content to the mobile terminal 170. Alternatively, when receiving a request from the mobile terminal 170, the arrangement instruction unit 203 may instruct a cache server to read the content from the delivery server apparatus 120 and to deliver the content to the mobile terminal 170 without instructing the temporary content accumulation unit 113 of the cache server to cache the content.
Next, the control apparatus 160 in
Alternatively, the following procedure may be added to the first procedure. Namely, as a second procedure, the cache server selection unit 187 uses load information about the group of cache servers selected in the first procedure, determines cache servers with load equal to or less than a predetermined threshold, and selects a cache server with minimum load.
Next, the cache server selection unit 187 instructs the cache server selected in accordance with the above procedure to deliver the content requested by the mobile terminal 170 via the control signal transmission and reception unit 161. If the content map of the content map creation and accumulation unit 167 indicates that the requested content is not cached in any one of the cache servers, which could be the case with contents with an extremely low access frequency, the cache server selection unit 187 instructs a cache server to acquire the content from the delivery server apparatus 120.
The content map creation and accumulation unit 167 receives a content list from each of the cache servers 110_1 to 110_N via the control signal transmission and reception unit 161, for example, at predetermined time intervals and creates and accumulates a content map indicating what contents are temporarily accumulated in which cache servers. In addition, the content map creation and accumulation unit 167 outputs the content map to the cache server selection unit 187 at predetermined time intervals or upon request.
Next, a configuration of the cache server 110_1 connected to the SGSN/GGSN apparatus 190_1 will be described with reference to the drawings.
The control signal transmission and reception unit 111 receives a GTP packet storing a connection request message sent by the mobile terminal 170, the IP address of the mobile terminal 170, the URL of a requested content, and the like from the SGSN/GGSN apparatus 190_1.
The analysis unit 115 reads the connection request message stored in a payload portion of the GTP packet, extracts information about the IP address of the mobile terminal 170, the URL of the requested content, and the like, and transmits the extracted information to the control apparatus 160 via the control signal transmission and reception unit 111. In addition, the analysis unit 115 outputs the information about the URL of the content and the like to the access number aggregation unit 130.
The content acquisition unit 112 receives a content arrangement instruction transmitted from the arrangement instruction unit 203 illustrated in
The temporary content accumulation unit 113 temporarily caches the content acquired and outputted by the content acquisition unit 112.
The content list creation unit 116 creates a content list of all the contents cached in the temporary content accumulation unit 113 of the cache server 110_1 at predetermined time intervals or when a predetermined condition is satisfied. In addition, the content list creation unit 116 transmits the content list of the cache server 110_1 to the control apparatus 160 via the control signal transmission and reception unit 111.
For each of the contents for which the cache server 110_1 receives a connection request, the access number aggregation unit 130 receives information about the URL of the requested content from the analysis unit 115. Based on the inputted information, the access number aggregation unit 130 calculates an access number per content by aggregating the number of connection requests from the mobile terminal 170 within a predetermined period of time. The access number aggregation unit 130 transmits an access number per content to the control apparatus 160 via the control signal transmission and reception unit 111.
The load status detection unit 135 measures a load status Q of the cache server 110_1 at predetermined time intervals or when a predetermined condition is satisfied and transmits the measured load status Q to the control apparatus 160 via the control signal transmission and reception unit 111. The load status detection unit 135 may measure the load status Q when the control apparatus 160 requests the cache server 110_1 to transmit the load status, which is an example of the predetermined condition. The load status detection unit 135 may measure the load status Q when a different condition is satisfied.
The load status detection unit 135 calculates the load status Q in accordance with formula (2).
In formula (2), Q is an index representing the load status of the cache server 110_1, j represents the number of a content temporarily accumulated in the cache server 110_1, Aj represents the number of requests made for a j-th content, and Sj represents the size of the j-th content. Alternatively, the load status detection unit 135 may calculate the load status by using a different formula other than formula (2).
The delivery unit 114 receives information about the URL of the requested content from the analysis unit 115. Based on this information, the delivery unit 114 searches the temporary content accumulation unit 113, reads the requested content, and generates a packet of a predetermined protocol. Next, the delivery unit 114 transmits the generated packet to the SGSN/GGSN apparatus 190_1 to deliver the packet to the mobile terminal 170 via the SGSN/GGSN apparatus 190_1. For example, a TCP protocol (Transmission Control Protocol) or an HTTP protocol (Hypertext Transfer Protocol) can be used as the predetermined protocol.
If the requested content is not cached in the temporary content accumulation unit 113 of a cache server and if the cache server selection unit 187 in
If the requested content is not cached in the temporary content accumulation unit 113 of a cache server and if the cache server selection unit 187 in
Various variations can be made to the content delivery system according to the first exemplary embodiment described above.
The number of control apparatuses 160 is not limited to one. Two or more control apparatuses may be arranged, and these control apparatuses may share processing. Alternatively, the control apparatus 160 may be incorporated in at least one cache server.
A predetermined value may be set as the threshold Th1 in the control apparatus 160. The threshold Th1 may be set to 0 or ∞. If the threshold Th1 is set to ∞, since the access frequency does not exceed Th1, the content arrangement calculation unit 185 does not arrange any contents in accordance with a predetermined arrangement. In addition, there may be cases where the control apparatus 160 does not use load information about each cache server.
The content arrangement calculation unit 185 may perform content arrangement calculation and instruct target cache servers to cache target contents at predetermined time intervals or when a predetermined condition is satisfied. The content arrangement calculation unit 185 may perform the above operations when the access frequency of a content aggregated by the access measurement unit 184 has changed from the past access frequency and a degree of the change exceeds a predetermined threshold, which is an example of the predetermined condition. However, the content arrangement calculation unit 185 can use a different condition other than the above condition. Alternatively, the content arrangement calculation unit 185 may calculate arrangement of contents based on a different configuration.
The load status detection unit 135 may calculate the load status by using a different formula other than the formula (2).
In
In addition, the delivery server apparatus 120 and the cache server apparatuses 110_1 to 110_N may be connected to each other.
In addition, the mobile terminal 170 may be a mobile phone, a smartphone, or a PC equipped with a data communication card. Alternatively, the mobile terminal 170 may be any terminal as long as the terminal can communicate with a mobile 3G network.
A content delivery system according to a second exemplary embodiment will be described with reference to the drawings.
In
In addition, in EPC, S/P-GW (Serving/Packet Data-Gateway) apparatuses are connected to corresponding eNodeB apparatuses. An S/P-GW apparatus is an apparatus in which an S-GW apparatus and a P-GW apparatus are integrated.
In
The mobile terminal 170 transmits a connection request message including the IP address of the delivery server apparatus 120. Next, an eNodeB apparatus (in
The cache server 110_1 has the same configuration as that of the cache server 110_1 (
In addition, in the present exemplary embodiment, the delivery server apparatus 120 is connected to each of the S/P-GW apparatuses 290_1 to 290_N.
Various variations can be made to the content delivery system according to the above second exemplary embodiment. However, since the same variations as those described in the first exemplary embodiment can be made, detailed description thereof will be omitted.
In addition,
For example, the following advantageous effects are provided by the content delivery systems according to the above first and second exemplary embodiments.
The control apparatus 160 arranges contents whose access frequency is higher than a threshold in two or more cache servers in a predetermined arrangement. For some of the contents whose access frequency is lower than a threshold, the control apparatus 160 uses access frequency information or the like to calculate arrangement of each of the contents in cache servers. In addition, the control apparatus 160 instructs the cache servers to cache the contents that are instructed to be arranged. After caching the contents temporarily, the cache servers deliver the contents.
In this way, even when there is a content with high popularity, concentration of load on the mobile network and concentration of accesses to the delivery server apparatus 120 can be avoided. Therefore, congestion on the mobile network can be avoided. These effects are more significant if more terminals are used or larger-capacity contents are delivered. There are other advantageous effects for users. Namely, since problems such as delay and packet loss are not caused, freeze-up of an image or interruption of voice on the terminal side is not caused.
In addition, for example, even when a new content is introduced and popularity of a certain content is rapidly changed, concentration of the traffic to the delivery server apparatus or of the traffic on a network can be avoided. Thus, congestion can be avoided, counted as an advantageous effect.
In addition, according to the content delivery systems, the above advantageous effects can be provided without making any modification to the terminal.
The disclosure of prior art including the above PTL is incorporated herein by reference thereto. Modifications and adjustments of the exemplary embodiments are possible within the scope of the overall disclosure (including the claims) of the present invention and based on the basic technical concept of the present invention. Various combinations and selections of various disclosed elements (including each element in each claim, example, drawing, etc.) are possible within the scope of the claims of the present invention. That is, the present invention of course includes various variations and modifications that could be made by those skilled in the art according to the overall disclosure including the claims and the technical concept. The description discloses numerical value ranges. However, even if the description does not particularly disclose arbitrary numerical values or small ranges included in the ranges, these values and ranges should be deemed to have been specifically disclosed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-194562 | Sep 2011 | JP | national |
The present application is a National Stage Entry of PCT/JP2012/072770 filed Sep. 6, 2012, which is based on and claims the benefit of the priority of Japanese Patent Application No. 2011-194562, filed on Sep. 7, 2011, the disclosures of all of which are incorporated herein in their entirety by reference.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2012/072770 | 9/6/2012 | WO | 00 | 3/7/2014 |
