JP5731353B2 - Cache server solving method, apparatus, and system - Google Patents

Description

  The present invention relates to a cache server on a network.

  When a large amount of data is returned from a distant content server via the network, problems arise in both the amount of network usage and the delay perceived by the end user. For this reason, a cache system is used in which a cache server is placed near the end user and data is returned therefrom. In such a system, 1) technology for finding a cache server near the end user and 2) technology for guiding the end user to the cache server are used.

  Patent Document 1 is one such system. In the system, a list of cache servers is passed from the cache system to the end user. Then, the end user's neighbor cache server search program pings the cache server in the list to measure the distance (here network delay is the distance), and solves the above 1) and 2) by selecting the closest one To do. The system requires the end user to have a dedicated distance measurement program.

  A typical conventional system that can be used as is by existing end users is Patent Document 2 and its family. Patent Document 2 is an ultra-large-scale system that returns contract content provider data from a company cache server in the vicinity of an end user for all end users connected to the Internet. For this reason, a method of returning a quasi-nearest neighbor cache server is used so that a search for a nearby company cache server can be processed in real time. Specifically, as described in Patent Document 2, a map in which the nearest cache server is assigned to each major DNS server of Internet provider and BGP (Border Gateway Protocol, routing message between routers) for 1) Use it to create a map that divides the Internet into IP (Internet Protocol) address zones, and combine them to create a quasi-nearest neighbor cache server allocation map for each IP address zone. In addition, using DNS (Domain Name System) rewriting technology for 2), the recursive inquiry destination of the Internet provider's DNS server X used by the end user is the DNS server of the system, and the DNS server of the system uses the address of the DNS server X Use 1) to return the best cache server from the map.

US Pat. No. 6,606,643, “Method of automatically selecting a mirror server for web-based client-host interaction”. US Patent Publication No. 2002/0129134, “Global load balancing across mirrored data centers”

  In the system described in Patent Document 1, it is necessary for an end user to run a dedicated distance measurement program, and it cannot be applied to a B2C (Business to Consumer) service that handles an unspecified number of end users.

  Since the mechanism described in Patent Document 2 can be optimized only for each DNS server, the DNS server used by the end user needs to be close to the end user. However, there is a problem that there is no guarantee that the DNS server used by the end user is close. Also, because today's DNS server has a performance of hundreds of thousands of queries per second, it can be estimated that it has at least tens of thousands of users per device. On the other hand, services with high required performance such as VOD (Video On-Demand) are responsible for thousands of users per server, so the granularity is coarse when allocating cache servers for each DNS server. As a result, there is a problem that extra costs occur, such as placing a load balancer and bundling a plurality of cache servers.

  Due to the above problems, the conventional method has a problem in a technique for solving a cache server in the vicinity of an end user in a B2C service that handles an unspecified number of end users.

  An object of the present invention is to provide a cache server solving method, apparatus, and system capable of solving the above-described problems, solving a cache server in the vicinity of an end user, and guiding the end user to the neighborhood cache server. is there.

  In order to achieve the above object, according to the present invention, there is provided a cache server solution for an apparatus for notifying a terminal of a cache server having a short distance on the network from a plurality of cache servers. Measure the distance on the network between the multiple relay devices and each of the multiple cache servers, hold the result of determining the cache server close to each of the multiple relay devices, and relay on the route on the network to the terminal If the cache server close to the relay device closest to the held terminal is acquired and the cache server close to the relay device closest to the terminal is not held, the device closest to the next closest relay device to the terminal Provided is a cache server solution that repeatedly searches and acquires a cache server.

  In order to achieve the above object, the present invention is a solution device that includes a processing unit and a storage unit, and notifies a terminal of a cache server having a short distance on the network from a plurality of cache servers. The storage unit measures the distance on the network between the plurality of relay devices on the network and each of the plurality of cache servers, and stores the result of determining the cache server close to each of the plurality of relay devices, the processing unit Inputs the identifier for identifying the terminal, investigates the relay device on the route on the network to the terminal, obtains the cache server close to the relay device closest to the terminal stored in the storage unit, and is closest to the terminal When the cache server close to the relay device is not held in the storage unit, the cache server closest to the next relay device is searched for and acquired from the terminal. The provides a solution system recursively repeats.

  Furthermore, in order to achieve the above object, the present invention provides a cache server system comprising a terminal, a plurality of cache servers, and a resolution device for notifying the terminal of a cache server having a short distance on the network. The device measures the distance on the network between a plurality of relay devices on the network and each of the plurality of cache servers, holds a result of determining a cache server close to each of the plurality of relay devices, and identifies a terminal When the identifier is input, the relay device on the route on the network is investigated, the cache server closest to the relay device closest to the retained terminal is obtained, and the cache server closest to the relay device closest to the terminal is not retained , Repeatedly search and acquire the cache server closest to the next closest relay device from the terminal To provide a cache server system which outputs the cache server.

  For an unspecified number of end users, a cache server near the end users can be solved.

1 is an overall view of a cache server solution system according to a first embodiment. It is a figure which shows the example which makes a router arrangement | sequence from the traceroute result based on Example 1. FIG. It is a figure which shows the example which calculates | requires distance from the ping result based on Example 1. FIG. It is a figure which shows one structure of the resolve manager (Resolve Manager) and the resolve agent (Resolve Agent) based on Example 1. FIG. FIG. 11 is a sequence diagram of initial neighborhood cache table construction processing according to the first embodiment. It is a figure which shows an example of the initial neighborhood cache table construction processing flow of Resolve Manager based on Example 1. FIG. It is a figure which shows the path | route investigation processing flow of Resolve Agent based on Example 1. FIG. It is a figure which shows an example of the distance measurement processing flow of Resolve Agent based on Example 1. FIG. It is a figure which shows an example of the sequence of the resolve process based on Example 1. FIG. It is a figure which shows an example of a sequence when a nearest neighbor cache is not found by the resolve process based on Example 1. FIG. It is a figure which shows an example of the neighborhood cache search processing flow of Resolve Manager based on Example 1. FIG. 6 is a diagram illustrating an example of a sequence of cache addition processing according to Embodiment 1. FIG. FIG. 10 is a diagram illustrating a sequence of cache deletion processing according to the first embodiment. It is a figure which shows the cache addition processing flow of Resolve Manager based on Example 1. FIG. It is a figure which shows the cache deletion processing flow of Resolve Manager based on Example 1. FIG. It is a figure which shows an example of the whole flow of Resolve Manager based on Example 1. FIG. It is a figure which shows an example of the whole flow of Resolve Agent based on Example 1. FIG. It is a general view of the cache server solution system based on Example 2. FIG. It is a figure which shows the structure of Resolve Manager and HTTP Data (Origin) based on Example 2. FIG. FIG. 10 is a diagram illustrating an example of a sequence of resolve processing according to the second embodiment. It is a figure which shows the resolve processing flow of Resolve Manager based on Example 2. FIG.

  Hereinafter, various embodiments of the present invention will be described with reference to the drawings.

  As a first embodiment, a VOD system using an end-user neighborhood cache server solution system will be described.

FIG. 1 shows an example of the overall configuration of the VOD system of this embodiment.
A data center (DC) 1011 includes a Resolve Manager 1012, a VOD Portal 1013, a VOD DRM (Digital Rights Management) 1014, and a VOD Data (Origin) 1015. The Resolve Manager 1012 is the main component of the end user neighborhood cache server resolution system of this embodiment. VOD Portal 1013, VOD DRM 1014, and VOD Data (Origin) 1015 are components of the VOD system. VOD Portal 1013 is a component that displays a portal site used by a user before viewing content such as a program guide. The VOD DRM 1014 is a component that distributes a key for decrypting encrypted content. VOD Data (Origin) 1015 is a component that actually distributes content.

  Cache servers 1021, 1031 and 1041 are placed at a distance from the DC 1011 on the network. The cache servers 1021, 1031, and 1041 include Resolve Agents 1022, 1032, and 1042, and VOD Data (Cache) 1023, 1033, and 1043. The Resolve Agents 1022, 1032, and 1042 are components of the end-user neighborhood cache server resolution system according to this embodiment, and operate in cooperation with the Resolve Manager 1012. VOD Data (Cache) 1023, 1033, and 1043 have the same functions and content as VOD Data (Origin) 1015, and are components that actually deliver the content.

  In this embodiment, RTT (Round Trip Time) is used as a guideline for measuring the distance on the network. Under the Internet protocol, RTT can be measured by ICMP (Internet Control Message Protocol). Also, this embodiment can be applied to other protocols if there is a means for measuring RTT.

  The DC 1011 and the cache servers 1021, 1031 and 1041 are connected by a network. In this embodiment, the Internet is assumed. Under the Internet protocol (IP), the network is configured by routers 1051 to 1058 which are a plurality of relay apparatuses. Note that a cache system similar to the present embodiment can be configured as long as it is an Internet protocol (IP) network even if it is an intranet or other closed network (Closed IP Network). In addition, even in a network of another protocol, a cache system similar to that of the present embodiment can be configured as long as it is a network using a relay device similar to a router.

  Information processing terminals 1061, 1062, and 1063 such as a television (TV) and a personal computer (PC) are connected to the DC 1011 and the cache servers 1021, 1031, and 1041 through a network. The information processing terminals 1061, 1062, and 1063 contain viewing clients of this VOD system. In the present embodiment related to the VOD system, the information processing terminals 1061, 1062, and 1063 may be any hardware such as a TV, a PC, and a smartphone as long as the viewing client operates. For convenience, the display may be “TV” on the drawing, but is not limited thereto.

  FIG. 4 shows an example of the detailed configuration of the Resolve Manager 1012 and Resolve Agents 1022, 1032, and 1042 in FIG.

  The Resolve Manager 1012 shown in the upper part of FIG. 4 has a computer configuration and includes a central processing unit (CPU) 4011 that is a processing unit, a main memory 4012 that is a storage unit, and a secondary storage 4013. On the main memory 4012, there are a manager module 4021, a neighborhood cache table 4022, and a cache server list 4023. The manager module 4021 is a runtime image of a program that controls the Resolve Manager. Details of the operation of the manager module 4012 will be described later with reference to FIG. The neighborhood cache table 4022 is a table holding the nearest neighbor cache server and the second nearest cache server for each router on the network.

  The neighborhood cache table 4022 shown in the middle of FIG. 4 is a router IP address column 4041 that identifies a router on the network, a Counter column 4042 that represents the access frequency, a cache server 1 column 4043 that holds the nearest cache, and the distance from that router. 1 column 4044, a stop flag 4045 indicating that the nearest cache server is temporarily stopped due to maintenance or the like, and three columns 4046, 4047, 4048 related to the second closest cache server. The primary key of the neighborhood cache table 4022 is a router IP address column 4041, and a specific one line can be limited using the router IP address column.

  A cache server list 4023 in the middle of FIG. 4 is a list of available cache servers on the network. The cache server list 4023 includes an ID column 4051 which is a serial number, a cache server IP address column 4052 for identifying a cache server, and a Resolve Agent IP address column 4053 for identifying a Resolve Agent. The cache server list 4023 also includes an entry of VOD Data (Origin) 1015 that is the original server at ID = 0. Since there is no corresponding Resolve Agent in VOD Data (Origin), the Resolve Agent IP address column 4053 is blank. The primary key of the cache server list 4023 is an ID column 4051, and a specific row can be limited using the ID column. Further, the cache server IP address column 4052 and the Resolve Agent IP address column 4053 are also unique columns, and a specific one line can be limited using each value. The secondary storage 4013 includes a manager module program 4031. When the Resolve Manager is operating, the manager module program 4031 is expanded on the main memory 4012 and executed as the manager module 4021.

  The Resolve Agent 1022 in the lower part of FIG. 4 has a computer configuration, and includes a CPU 4061 that is a processing unit, a main memory 4062 that is a storage unit, and a secondary storage 4063. The main memory 4062 has an agent module 4071. The agent module 4071 is an execution image of a program that controls the Resolve Agent. Details of the operation of the agent module will be described later with reference to FIG. The secondary storage 4063 includes an agent module program 4081. When the Resolve Agent operates, the agent module program 4081 is expanded on the main memory 4062 and executed as the agent module 4071.

  Next, operation details of the VOD system of this embodiment using the end-user neighborhood cache server resolution system will be described. Specifically, the initial neighborhood cache table construction process at the start of the system, the process when the information processing terminal that is operating in the steady state is viewing content, the process when adding a new cache server to the system, and deletion Process.

FIG. 5 shows a sequence of initial neighborhood cache table construction processing at the time of system start. This process is performed between the Resolve Manager 1012 and the Resolve Agents 1022, 1032, and 1042.
First, the Resolve Manager 1012 issues a route investigation instruction 5001 between the Resolve Manager 1012 and all Resolve Agents 1022, 1032, 1042 to all Resolve Agents 1022, 1032, 1042. As a result, a total of six paths between the Resolve Manager 1012 and the Resolve Agent 1022, between the Resolve Manager 1012 and the Resolve Agent 1032, between the Resolve Manager 1012 and the Resolve Agent 1042, between the Resolve Agent 1022 and the Resolve Agent 1032, between the Resolve Agent 1022 and the Resolve Agent 1042, and between the Resolve Agent 1032 and the Resolve Agent 1042. The upper router becomes clear.

  Subsequently, these routers are made into one list by deduplication or the like (5002). Subsequently, the first router in the list is taken out and designated as router A (5003), and a distance measurement instruction 5004 with respect to router A is issued to all the Resolve Agents 1022, 1032, and 1042. The results are totaled and the top two closest routers are added to the neighborhood cache table 4022. Here, the value of the counter row 4042 is 0, and the stop flags 1 (4045) and 2 (4048) are off. Thereafter, the processing is repeated until the end of the list (5006, 5007,...), And an initial neighborhood cache table is constructed. Hereinafter, the processing flow of each module related to this processing will be described.

  FIG. 6 shows a flowchart of the processing portion of the Resolve Manager 1012 in the initial neighborhood cache table construction processing at the time of starting the system. The Resolve Manager 1012 issues a route investigation instruction to all the Resolve Agents 1022, 1032, and 1042 after starting the initial neighborhood cache table construction process (6001). Specifically, an instruction is issued to all Resolve Agents 1022, 1032, and 1042 in the procedure shown in the following pseudo code.

n = rows_of (cache server list)
for a in {1, 2,…, n-1}
for b in {0, 1,…, n-1}
if b <a
router_array. add (ResolveAgent $ {a}. Route survey (ResolveAgent $ {b}))
fi
done
done
Subsequently, the route investigation results from all the Resolve Agents 1022, 1032, and 1042 are received as a router array, and a router array from which duplicates are eliminated is created (6003). Subsequently, the head of the router array is copied to the variable router A (6004), the head element of the router array is deleted (6005), and a distance measurement instruction to the router A is issued to all Resolve Agents 1022, 1032, and 1042 (6006). ). Subsequently, the results of distance surveys from all the Resolve Agents 1022, 1032, and 1042 are received, and the top two closest distances are selected, and records are registered in the neighborhood cache table (6007). Here, the value of the Count column 4042 is 0, and the values of the two stop flags 4045 and 4048 are off. Subsequently, it is determined whether there is a continuation in the router array (6008). If there is a continuation, the process returns to step 6004. If there is no continuation, the process ends (6009).

  FIG. 7 shows a flowchart of the route investigation processing part of the Resolve Agents 1022, 1032, and 1042 in the initial neighborhood cache table construction processing at the time of starting the system. Resolve Agents 1022, 1032, and 1042 start route investigation processing with router X (7001), issue a traceroute to router X (7002), measure the route, return the result to Resolve Manager 1012 (7003), and finish the processing (7004).

  FIG. 2 shows a specific example of the procedure 7003. In FIG. example. com [a1. a2. a3. a4] to zzz. example. com [z1. z2. z3. This is an example of issuing traceroute to [z4]. As a result of traceroute, zzz. example. You can see it arriving at com. From this result, [b1. b2. b3. b4] [c1. c2. c3. c4] [d1. d2. d3. d4] [e1. e2. e3. e4] is obtained.

  Although the traceroute program widely used as a means for acquiring a route is used here, another program having the same function may be used.

  FIG. 8 shows a flowchart of the distance measurement processing portion of the Resolve Agents 1022, 1032, and 1042 in the initial neighborhood cache table construction processing at the time of starting the system. Resolve Agents 1022, 1032, and 1042 start distance measurement processing with router X (8001), issue a ping to router X (8002), measure the route, return the result to Resolve Manager 1012 (8003), and terminate the processing (8004).

  FIG. 3 shows a specific example of the procedure 8003. In FIG. example. com [a1. a2. a3. a4] to zzz. example. com [z1. z2. z3. This is an example of issuing a ping to [z4]. As a result of pinging, it can be seen that the average of four RTTs is 11 ms. From this result, a distance of 11 ms is obtained. Although the ping program widely used as a means for measuring the distance is used here, another program having the same function may be used.

  Although a router on the path between cache servers is found and registered here, other known routers can be manually registered. In particular, it is conceivable to register a router at a location where a plurality of connections such as IX (Internet Exchange) are aggregated. With the processing so far, the initial neighborhood cache table can be constructed at the time of starting the system.

  Next, FIG. 9 shows a processing sequence when the information processing terminal, which is an operation in a steady state, views content. In this processing, first, the information processing terminal 1061 connects to the VOD Portal 1013 and browses a program guide (9001). On the other hand, the VOD Portal 1013 acquires a neighborhood cache address from the Resolve Manager 1012. Here, the Resolve Manager 1012 traceroutes to the information processing terminal 106), investigates the neighboring router of the information processing terminal 1061 (9003), and returns the address of the neighboring cache server using the neighboring cache table. Thereafter, when the information processing terminal 1061 determines a program to be viewed, there is a program metadata request (9004). The VOD Portal 1013 returns the URL (Uniform Resource Locator) of the content and the URL of the DRM key for the content as program metadata. At this time, the URL in the neighborhood cache server acquired in step 9002 is returned as the content URL. Thereafter, the information processing terminal 1061 that has received the metadata of the program requests the content from an appropriate cache (9005), and requests a DRM key from the VOD DRM 1014.

  Note that in the procedure 9002, it is not always possible to return a cache server in the vicinity of the information processing terminal 1061. Therefore, if the cache server in the vicinity of the information processing terminal 1061 cannot be returned in the procedure 9002, the alternative cache server is returned based on the processing sequence shown in FIG. . In this processing, first, the information processing terminal 1061 connects to the VOD Portal 1013 and browses a program guide (9001). On the other hand, the VOD Portal 1013 acquires a neighborhood cache address from the Resolve Manager 1012. Here, the Resolve Manager 1012 traceroutes to the information processing terminal 1061, investigates the neighboring router of the information processing terminal 1061 (9003), searches the neighboring cache server using the neighboring cache table, but cannot find the nearest router of the second nearest router. The neighbor cache server is returned (10001). Thereafter, the information processing terminal 1061 requests the metadata of the program (9004), requests the content from an appropriate cache (9005), and requests the DRM key from the VOD DRM 1014. On the other hand, the Resolve Manager 1012 receives all the Resolve Agents 1022 1032 and 1042, a distance measurement instruction (10002) with the router nearest to the information processing terminal 1061 is issued, a nearby cache server is determined, and a record is created (10003). As a result of this processing, the nearest cache server can be used when the information processing terminal 1061 views the program again or when the other information processing terminals 1062 and 1063 view the program.

Hereinafter, the processing flow of each module related to this processing will be described.
FIG. 11 shows a flowchart of the processing portion of the Resolve Manager 1012 in the processing when the information processing terminal views the content, which is the operation in the steady state. The Resolve Manager 1012 traces to the information processing terminal 1061 after starting the neighborhood cache search process of the information processing terminal (11001), and acquires the router array (11002). Subsequently, the end of the router array is copied to the variable router A (11003). The end of the router array is the router closest to the information processing terminal 1061.

  Subsequently, the record of the router A is searched from the neighborhood cache table (11004), and it is determined whether it has been found (11005). If found, it is determined whether or not the stop flag 1 in the record is off (11006). If it is off, that is, if the cache server 1 is in operation, the URL of the cache server 1 is returned (11007). When the stop flag 1 is on, the stop flag 2 is determined (11008). If the stop flag 2 is off, the URL of the cache server 2 is returned (11009). If the stop flag 2 is also ON, it is determined whether there is a continuation in the router array (11010) as in the case where it is not found in the determination 11005. If there is a continuation, the router A is a temporary area used in this processing. Add to the search array (11012), delete the end of the router array (11013), and return to step 11003. If the router array is not continued in the decision 11010, the URL of VOD Data (Origin) 1015 is returned (11010). With the processing so far, the best cache server (including the origin server) at the present time can be returned to the VOD Portal 1013. Subsequently, the neighborhood cache server search process of the nearest router described in FIG. 10 is performed. First, it is determined whether or not there is an element in the search array, which is a temporary area (11014). If there is no element, the process ends as it is (11019). If there is an element, the head of the search array is copied to variable router A (11015), the head of the search array is deleted (11016), and all Resolve Agents 1022, 1032, and 1042 are instructed to measure the distance to router A (11017). Put out. Subsequently, the distance survey results from all the Resolve Agents 1022, 1032, and 1042 are received, the top two items having the closest distances are selected, records are registered in the neighborhood cache table (11018), and the procedure returns to step 11014.

  Note that some routers do not return an ICMP message and cannot identify which route was taken. In that case, such a router removes it from the router array and executes the above processing. If all routers on the route do not return the ICMP message, the cache server closest to the information processing terminal is searched and returned.

  With the processing so far, it is possible to solve the neighborhood cache server when the information processing terminal, which is the operation in the steady state, views the content.

  Next, FIG. 12 shows a process when a new cache server is added to the system, and a process sequence when a cache server is deleted from the system shown in FIG.

  The processing for adding a new cache server to the system is performed between the Resolve Manager 1012 and the Resolve Agent 12002 of the newly added cache server 12001. First, the Resolve Agent 12002 issues a cache addition processing instruction (12004) to the Resolve Manager 1012. Subsequently, the Resolve Manager 1012 adds a record related to the cache server 12001 to the cache server list 4023 (12005). Subsequently, the router on the first line of the neighborhood cache table 4022 is taken out and designated as router A (12006), and a distance measurement instruction (12007) to the router A is issued to the Resolve Agent 12002. Here, the result is stored in the record of the neighborhood cache table 4022. Since it is closer than the distance, the record is updated (12008). Subsequently, the router on the second line of the neighborhood cache table 4022 is taken out and designated as router A (12009), and a distance measurement instruction (12010) to the router A is issued to the Resolve Agent 12002. Here, the result is stored in the record of the neighborhood cache table 4022 The record is not updated because it is further than the distance. Thereafter, the same processing is continued from the third row (12011) of the neighborhood cache table 4022 to the end of the neighborhood cache table.

  On the other hand, processing for deleting a cache server from the system is performed between the Resolve Manager 1012 and all Resolve Agents 1022, 1032, 1042, and 12002. First, the Resolve Agent 12002 of the cache server 12001 to be deleted issues a cache deletion processing instruction (13001) to the Resolve Manager 1012. Subsequently, the Resolve Manager 1012 deletes the record related to the cache server 12001 to be deleted from the cache server list 4023 (13002). Subsequently, the router in the first row among the plurality of rows related to the cache server 12001 to be deleted from the neighborhood cache table 4022 is taken out as router A (13003), and the Resolve Agents 1022, 1032, and 1042 of the cache server 12001 to be deleted from now on. A distance measurement instruction (13004) is issued to router A, and the record is updated using the result (12008). Thereafter, the same process is continued from the second line (13006 to 13008) and the third line (13009) of the plurality of lines related to the cache server 12001 to be deleted from the end of the neighborhood cache table.

  FIG. 14 shows a flowchart of the processing portion of the Resolve Manager 1012 in the processing when a new cache server is added to the system. The Resolve Manager 1012 first adds a record related to the cache server C to the cache server list 4023 after starting the addition process of the cache server C (14001) (14002). Subsequently, the router IP address column 4041 of all records is extracted from the neighborhood cache table 4022, and a router array is created (14003). Subsequently, the head of the router array is copied to the variable router A (14004), the head of the router array is deleted (14005), a distance measurement instruction (14006) with the router A is issued to the Resolve Agent of the cache server C, and the result is displayed. receive. It is determined whether or not the distance and the line related to the router A in the neighboring cache table 4022 are closer to the cache server 1 (14007). If the distance is close, the cache server 2 and the distance 2 in the line related to the router A in the neighboring cache table 4022 are The cache server 1 is updated with the value of the distance 1 (14008), and the cache server 1 and the distance 1 of the row related to the router A in the neighborhood cache table 4022 are updated with the IP address and the distance of the cache server C (14009). If it is determined in the determination 14007 that it is far, then it is determined whether the distance between the cache server C and the router A and the line related to the router A in the neighborhood cache table 4022 is closer to the cache server 2 (14010). The cache server 2 and the distance 2 in the line related to the router A of the server A are updated with the cache server 1 and the distance 1 with the IP address and distance of the cache server C (14011). Subsequently, it is determined whether there is a continuation in the router array (14012).

FIG. 15 shows a flowchart of the processing portion of the Resolve Manager 1012 in the processing when deleting the cache server from the system. The Resolve Manager 1012 first deletes the record related to the cache server C from the cache server list 4023 (15002) after starting the deletion process of the cache server C (15001). Subsequently, the router IP address column 4041 of all records including the cache C is extracted from the neighborhood cache table 4022, and a router array is created (15003). Subsequently, the head of the router array is copied to the variable router A (15004), the head of the router array is deleted (15005), and the distance measurement instruction (15006) with respect to the router A is sent to all Resolve Agents 1022, 1032, and 1042 other than the cache server C. ) And receive the result. Based on the result, the top two items that are closest to each other are selected, and the record related to router A in the neighborhood cache table 4022 is updated (15007). Subsequently, it is determined whether there is a continuation in the router array (15008).
With the processing so far, a new cache server can be added to and deleted from the system.

Finally, the individual processing procedures described so far are integrated, and the operation of the Resolve Manager is shown in FIG. 16, and the operation of the Resolve Agent is shown in FIG.
After the Resolve Manager is started (16001), the cache server is registered in the cache server list (16002). This is a list of cache servers to be given as initial values, which are manually entered here. There are other methods such as writing to the configuration file and receiving instructions for adding the Resolve Agent cache. Subsequently, the manager module is activated (16003), and the initial neighborhood cache table construction process of FIG. 6 is executed (16004). After this, you can wait for a processing request. If there is an inquiry about the neighborhood cache (16005), the neighborhood cache search process of the information processing terminal in FIG. 11 is executed (16006). If there is a cache server addition process request (16007), the cache C addition process of FIG. 14 is executed (16008). If there is a cache server deletion processing request (16009), the cache C deletion processing of FIG. 15 is executed (16010). If there is a maintenance report for the cache server (16011), and if it is a maintenance report, the IP address of the cache server that reported in the neighborhood cache table (4022) is stored in the cache server 1 column (4043). The line including the stop flag 1 (4045) is turned on (16012), and the line including the cache server 2 column (4046) is turned on the stop flag 2 (4048) (16012). If it is also a maintenance end report, turn it off.

  The Resolve Agent starts (17001), then starts the agent module (17002), and instructs the Resolve Manager to perform cache addition processing (17003). After this, you can wait for a request for processing. When there is a route investigation request (17004), a route investigation process with the router X in FIG. 7 is executed (17005), and when there is a distance investigation request (17006), a distance measurement process with the router X in FIG. Execute (17007). If there is an explicit termination instruction from the administrator during this standby (17008), the Resolve Manager is instructed to delete the cache (17009), and the Resolve Agent is terminated (17010).

  Here, a web content distribution system using the end-user neighborhood cache solution system of this embodiment will be described. Unlike the case of VOD, the web content distribution system needs to return content immediately in response to a content request from an end user. Therefore, there is a feature that processing that takes time such as traceroute cannot be performed. Therefore, in this embodiment, the configuration and operation of the Resolve Manager are changed in accordance with this feature.

FIG. 18 shows the overall configuration of this embodiment.
The DC 1011 includes a modified Resolve Manager 18001 and HTTP Data (Origin) 18002 as a content distribution device that is a WEB content distribution component.

The cache servers 1021, 1031, and 1041 include Resolve Agents 1022, 1032, and 1042 and HTTP Data (Cache) 18003, 18004, and 18005. The same Resolve Agents 1022, 1032, and 1042 are used as in the first embodiment. HTTP Data (Cache) 18003, 18004, and 18005 have the same functions and content as HTTP Data (Origin) 18002, and are components that actually deliver the content. However, if the URL of a tag having a link such as an A tag or an IMG tag in the content has an absolute path, it is replaced with the URL of each HTTP Data (Cache).
In this embodiment, PCs 18006, 18007, and 18008 are clients, and a general web browser is assumed as the client program. Note that the hardware of the information processing terminal such as a PC or a smartphone is not limited as long as the web browser operates.

FIG. 19 shows the detailed configuration of the changed Resolve Manager 18001 and HTTP Data (Origin) 18002.
The Resolve Manager 18001 includes a CPU 19011, a main storage 19012, and a secondary storage 19013. On the main memory 19012, a manager module 19021, a neighborhood cache table 19022, a cache server list 19023, and a traceroute table 19024 are included. Among these, the manager module 19021 is obtained by changing the manager module 4021 of the first embodiment. The neighborhood cache table 19022 and the cache server list 19023 are the same as the neighborhood cache table 4022 and the cache server list 4023 of the first embodiment, respectively. The traceroute table 19024 has a PC address column 19041 and a router array column 19042, and stores a router on the route to a certain PC.

  Note that the primary key of the traceroute table 19024 is the PC address column 19041, and a specific row can be limited using the PC address column. The secondary storage 19013 includes a manager module program 19031. When the Resolve Manager 18001 operates, the manager module program 19031 is expanded on the main memory 19012 and executed as the manager module 19021.

  HTTP Data (Origin) 18002 includes a CPU 1905, a main memory 1905, and a secondary storage 19053. An HTTP server 19061 and a rewrite module 19062 are included on the main memory 19052. Among these, the HTTP server 19061 uses a general-purpose HTTP server 19061. The rewrite module enters between the HTTP server 19061 and the PCs 18006, 18007, and 18008, and has a function of rewriting the URL of a tag having a link such as an A tag or an IMG tag in the content. The secondary storage 19053 includes an HTTP server program 19071 and a rewrite module program 19072. When the HTTP Data (Origin) 18002 operates, the HTTP server program 19071 and the rewrite module program 19072 are expanded on the main memory 19052 and executed as the HTTP server 19061 and the rewrite module 19062.

  Next, operation details of the WEB content distribution system using the end user neighborhood cache solution system will be described. However, the initial neighborhood cache table construction process at the time of starting the system, the process when adding a new cache server to the system, and the process when deleting it are the same as in the first embodiment. A process when a certain PC acquires contents will be described.

  FIG. 20 shows a processing sequence when the PC, which is an operation in the steady state, acquires content. In this process, the PC 18006 first connects to HTTP Data (Origin) 18002 and requests a top page (20001). Subsequently, HTTP Data (Origin) 18002 obtains the neighborhood cache address from Resolve Manager 18001 (20002), but here, Resolve Manager 18001 did not find the record of PC 18006 even after searching the traceroute table 19024 (20003). Origin) 18002 is returned (20004). Therefore, HTTP Data (Origin) 18002 returns the content without rewriting the address in the content to PC 18006 (20005). On the other hand, Resolve Manager 18001 traceroutes to PC 18006 and registers the result in traceroute table 19024 (20006). Subsequently, when the PC 18006 requests a subsequent page (20007), the HTTP Data (Origin) 18002 again obtains a neighborhood cache address from the Resolve Manager 18001 (20008). At this time, the traceroute result is registered in the traceroute table 19024 in step 20006. Therefore, when the traceroute table is searched, a record is found (20009). Therefore, the neighboring cache server is resolved using the record, and the address of the neighboring cache server is returned (20010). Subsequently, HTTP Data (Origin) 18002 rewrites the address in the content using the address of the neighboring cache server and returns the content (20011). The subsequent content requests from the PC 18006 are directed to HTTP Data (Cache) 1 (18003) on the cache server 1 (1021) (20012).

FIG. 21 shows a flowchart of the neighborhood cache search process of the PC, which is the process part of the Resolve Manager 18001, in the process sequence when the PC acquires the content as the operation in the steady state. In this embodiment, this process replaces the neighborhood cache search process (16006) of the information processing terminal in the entire Resolve Manager process of FIG. The Resolve Manager 18001 first judges whether there is an entry for the PC in the traceroute table after starting the PC neighborhood cache search process (21001) (21002). If there is no entry as a result of determination, the URL of HTTP Data (Origin) 18002 is returned (21003), and then a record is created from the router array obtained by traceroute to PC 18006 and added to the traceroute table (19024) (21004) Then, the process ends (21005). On the other hand, if there is an entry as a result of judgment 21002, the router array is acquired from the entry in the traceroute table (21006). Since the subsequent processing is the same as the processing 11003 to 11018 of FIG.
With the processing so far, it is possible to solve the neighborhood cache server when the PC, which is the operation in the steady state, acquires the content.

  Of the neighborhood cache table 4022, cache server list 18022, and traceroute table 19024 used by the Resolve Manager 18001, the neighborhood cache table 4022 and the traceroute table 19024 may have an unlimited number of records. On the other hand, a method of deleting a record with low importance by giving an upper limit to the number of records is effective. In the case of the neighborhood cache table 4022, a record with low importance has a small value in the counter column 4042 indicating the number of accesses. Therefore, in this case, deletion is performed in ascending order of the value in the couter column 4042 based on an LRU (Least Recently Used) algorithm. If the access count is not known, such as the traceroute table 19024, the old row, that is, the row at the top of the table, is determined to be less important based on the FIFO (First In First Out) algorithm.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

  Each of the above-described configurations, functions, processing units, processing means, and the like may be realized by hardware by designing a part or all of them with, for example, an integrated circuit. In addition, each configuration, function, and the like have been described by exemplifying a case where they are realized by software by executing a program that realizes each function. However, information on programs, tables, files, and the like that realize each function It can be stored not only in memory, but also in recording devices such as hard disks and SSDs (Solid State Drives), or recording media such as IC cards, SD cards, and DVDs. It is also possible to do.

The contents of the disclosure of the present invention described above include various inventions in addition to the inventions described in the respective claims. An example is as follows.
Example 1: An apparatus solution method for inputting an ID for identifying a device A and returning an ID for identifying another device B having a short distance on the network to the device A from among several other devices having the same function Because
Measure the distance between several relay devices on the network in advance and several other devices with the same function, and determine another device with a short distance on the network for some relay devices on the network And keep it as a list,
When the ID for identifying the device A is input, the relay device on the route on the network to the device A is investigated, and the relay device is arranged.
Search the relay device closest to the device A from the previously held list, obtain another device B closest to the relay device closest to the device A,
If the relay device closest to device A is not included in the pre-stored list, a search is made from the pre-held list using the relay device that is the second closest to device A, and the relay that is the second closest to device A. Get another device B closest to the device,
Similarly, if the relay device that is nth closest to device A is not included in the list held in advance, the device A searches from the list held in advance using the relay device that is closest to n + 1 from device A. obtain another device B closest to the n + 1th closest relay device and return device B,
Device solution.

1011 Data Center (DC)
1012, 18001 Resolve Manager 1013 VOD Portal
1014 VOD DRM
1015 VOD Data (Origin)
1021, 1031, 1041 Cache server 1022, 1032, 1042 Resolve agent 1023, 1033, 1043 VOD Data (Cache)
1051, 1052, 1053, 1054, 1055, 1056, 1058, 1059 Router 1061, 1062, 1063 Information processing terminal 4011, 4061, 19011, 19051 CPU
4012, 4062, 19012, 19052 Main memory 4013, 4063, 19013, 19053 Secondary memory 4021, 19021 Manager module 4022, 19022 Neighborhood cache table 4023, 19023 Cache server list table 4031, 19031 Manager module program 4041 Router IP
4042 Counter 4043, 4046 Cache server 4044, 4047 Distance 4045, 4048 Stop flag 4051 ID
4052 Cache server IP
4053 Resolve Agent IP
4081 Agent module programs 18002, 18003, 18004, 18005 HTTP Data (Cache)
18006, 18007, 18008 Personal computer (PC)
19041 PC address 19042 Router array 19061 HTTP server 19062 Rewrite module 19071 HTTP server program 19072 Rewrite module program

Claims (15)

A cache server solution for an apparatus for notifying a terminal of a cache server having a short distance on a network from a plurality of cache servers,
The device is
Measure the distance on the network between the plurality of relay devices on the network and each of the plurality of cache servers, hold the result of determining the cache server that is close to each of the plurality of relay devices,
Investigate the relay device on the network path to the terminal,
The cache server closest to the relay device closest to the held terminal is acquired, and when the cache server close to the relay device closest to the terminal is not held, the relay device closest to the next to the terminal Repeatedly searching for and obtaining the near cache server;
A cache server solution characterized by the above. The cache server solving method according to claim 1,
The device is
Investigate the relay device on the route on the network to the terminal in advance, hold the result as a list of the array of relay devices,
When an identifier for identifying the terminal is input, search from a list of the arrangement of the relay devices held in advance,
A cache server solution characterized by the above. The cache server solving method according to claim 2,
The device is
By examining the relay device in the vicinity of the terminal by traceroute to the terminal,
A cache server solution characterized by the above. The cache server solving method according to claim 1,
The terminal includes a client for viewing a video distribution system,
The cache server caches video data of the video distribution system;
A cache server solution characterized by the above. The cache server solving method according to claim 1,
The terminal includes a client program for requesting content distribution to a content distribution device,
The device is
When the terminal makes a distribution request to the content distribution device, if the cache server in the vicinity of the terminal cannot be searched, the content is returned from the content distribution device and the relay device on the route on the network to the terminal is investigated. And hold the result,
A cache server solution characterized by the above. A resolution device that includes a processing unit and a storage unit and notifies a terminal of a cache server having a short distance on the network from a plurality of cache servers,
In the storage unit,
Measure the distance on the network between the plurality of relay devices on the network and each of the plurality of cache servers, hold the result of determining the cache server that is close to each of the plurality of relay devices,
The processor is
Enter an identifier for identifying the terminal, investigate the relay device on the network path to the terminal,
When the cache server close to the relay device closest to the terminal stored in the storage unit is acquired, and the cache server close to the relay device closest to the terminal is not held in the storage unit, from the terminal Recursively repeating the search and acquisition of the cache server close to the next closest relay device,
The solution apparatus characterized by the above-mentioned. It is a solution apparatus of Claim 6, Comprising:
The storage unit stores, as the result, an IP address of the relay device, an IP address of the cache server, and a table that holds a distance between the relay device and the cache server on the network.
The solution apparatus characterized by the above-mentioned. It is a solution apparatus of Claim 6, Comprising:
The processor is
By examining the relay device in the vicinity of the terminal by traceroute to the terminal,
The solution apparatus characterized by the above-mentioned. It is a solution apparatus of Claim 6, Comprising:
The terminal includes a client for viewing a video on demand (hereinafter, VOD) system,
The cache server caches VOD data of the VOD system;
The solution apparatus characterized by the above-mentioned. The solution device according to claim 9,
The processor is
If the cache server that caches the VOD data is not found by recursive search, the original URL of the VOD data is returned.
The solution apparatus characterized by the above-mentioned. A cache server system comprising: a terminal; a plurality of cache servers; and a resolution device that notifies the cache server of a short distance on the network to the terminal,
The solving apparatus includes:
Measure the distance on the network between the plurality of relay devices on the network and each of the plurality of cache servers, hold the result of determining the cache server that is close to each of the plurality of relay devices,
Enter an identifier for identifying the terminal, investigate the relay device on the route on the network,
If the cache server closest to the relay device closest to the held terminal is acquired and the cache server closest to the relay device closest to the terminal is not held, the cache closest to the relay device next closest to the terminal Sequentially searching for and acquiring a server and outputting the acquired cache server;
A cache server system characterized by that. The cache server system according to claim 11,
As a result, the resolution device holds the IP address of the relay device, the IP address of the cache server, and the distance between the relay device and the cache server on the network.
A cache server system characterized by that. The cache server system according to claim 11,
The solving apparatus includes:
By examining the relay device in the vicinity of the terminal by traceroute to the terminal,
A cache server system characterized by that. The cache server system according to claim 11,
A portal distribution device capable of distributing the program table of the video distribution system;
The terminal includes a viewing client of the video distribution system,
The cache server can cache the video data of the video distribution system,
The resolution apparatus outputs the acquired cache server to the portal distribution apparatus,
When the portal distribution device receives a video distribution request from the terminal, it returns the cache server to the terminal,
The terminal receives a video from the cache server;
A cache server system characterized by that. The cache server system according to claim 11,
A content distribution device for distributing content;
The terminal includes a client program for requesting content distribution to the content distribution device,
The solving apparatus includes:
When the terminal makes a distribution request to the content distribution device, if the cache server in the vicinity of the terminal cannot be resolved, the content is returned from the content distribution device and the relay device on the route on the network to the terminal is investigated. And hold the result,
A cache server system characterized by that.

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