JP2003209566A - Routing method and system thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a routing method for guiding a client of a mobile network to an optimum edge server by performing request routing obtained by taking the position of the client into consideration, and a system for the routing method. <P>SOLUTION: In this routing method for selecting a communication path between the client 1 being a mobile terminal and a plurality of distributedly arranged edge servers 3a and 3b, if an HTTP contents router 4 for selecting the communication path is arranged, the client 1 attaches his/her own movement information to a transfer request when the client 1 uses a communication protocol used in transferring contents to transmit the transfer request to the HTTP contents router 4, and the contents router 4 selects the communication path on the basis of the attached movement information. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a routing method and its system. In particular, the present invention relates to a routing method and system capable of delivering contents to a client of a mobile network by routing considering the position of the client.

[0002]

2. Description of the Related Art At present, a content distribution network (CDN) that distributes content to a server (edge server) in the vicinity of a client in advance as the access network becomes wider and the capacity of Web content becomes larger.
livery network) is attracting attention. Request Routing System (RRS)
m) is a component of the CDN, and is a system for guiding a request for a client content to an edge server having a copy of the available content. There are the following two basic functions of the request routing system. 1) Direct the client to an edge server that can respond to the request. 2) Guide the client to the edge server that can provide the best service.

Currently, a request routing system used when distributing contents provided on a website using a CDN is "In-Lin".
There is an e "request routing system. In this system, the client is, for example, HTTP (Hyper).
A content request is made using the Text Transfer Protocol. Then, when a proxy or a layer 7 router for routing the network receives the HTTP request, these routers receive the I (I) of the transmission source (client) included in the request.
It refers to the P address and guides the client to the optimum edge server based on the address. By the way, the mobile (mobile IP) network to which the client belongs is usually divided into a plurality of areas, and the client moves in each area as appropriate.
In this case, the “home network” is defined as the area to which the client originally belongs, and the IP address of the client is assigned the address (home address) when the client is considered to exist in the home network.

[0004]

However, in the case of the above system, the IP address of the client added to the HTTP request is always the above home address. Therefore, since the address referred to by the router is also the home address, this router always directs the edge server existing in the home network to the client.
Therefore, even when the client moves from the home network to another area (external network), the edge server of the remote home network is guided, which causes a problem.

Further, with respect to the edge server, a problem called a triangle problem (Triangle Routing) may occur.
That is, the client is
Although the content is acquired from the edge server guided by the system, when the content is transmitted to the client in the destination area, the communication between the client and the edge server does not become a linear path, and the client In some cases, the home network and the edge server may have a triangular communication path, that is, a communication path that makes a large detour, which may put pressure on the network band between the home network and the external network.

[0006] The present invention has been made in view of the above-mentioned circumstances, and provides a client for a mobile network with
It is an object of the present invention to provide a routing method and a system thereof that can guide an optimum edge server by performing request routing considering the position of a client.

[0007]

In order to achieve the above object, according to the invention of claim 1, a client, which is a terminal that moves in a mobile network, and a plurality of contents distributed in the network to distribute contents are provided. In a routing method for selecting a communication path to an edge server to be distributed to the client, when the router for selecting the communication path is arranged, the client is used when transferring the content on the network. When the transfer request is transmitted to the router using a communication protocol, the transfer request includes its own movement information, and the router selects the communication path based on the added movement information. Is characterized by. According to the present invention, when a client sends a transfer request for content to a router, the router adds its own movement information to the transfer request. A communication path can be selected. Therefore, the router can select the communication route in consideration of the position of the client, and when the content related to the transfer request exists in the plurality of edge servers, the content is delivered from the edge server near the destination of the client. You can

According to the second aspect of the invention, the first aspect is
The communication protocol described in (1) is a protocol for transferring data described in a predetermined description language.

In the invention according to claim 3, the invention according to claim 1
Alternatively, the mobile network described in 2 is composed of a plurality of areas, and the movement information of the client has an address in the movement area of the client.

In order to achieve the above-mentioned object, in the invention according to claim 4, a client which is a terminal moving in a mobile network, and an edge which is distributed in the network and a plurality of which are arranged to distribute contents to the client. In a routing method for selecting a communication path with a server, the mobile network is composed of a plurality of areas, a first router for selecting the communication path is arranged, and the home is an area to which the client originally belongs. When the second router that receives the movement information from the client is arranged in the network and the client does not exist in the home network, the second router collects the packet transmitted to the client. While receiving and forwarding to the client, It transmits the movement information of the client to the first router, the first router, and selects the communication path based on the received movement information.

According to the invention of claim 5, claim 1
The edge server according to any one of items 1 to 4 automatically selects the shortest path as a communication path between the edge server and the client.

In order to achieve the above-mentioned object, in the invention according to claim 6, a client which is a terminal moving in a mobile network, and a plurality of edges which are distributed and distributed in the network to distribute contents to the client A routing system for selecting a communication path with a server, wherein when the client sends the transfer request using a communication protocol used when the client transfers the content in the network, It is characterized in that an addition means for adding own movement information to the transfer request is provided, and a router for selecting the communication route based on the movement information is provided.

In order to achieve the above object, in the invention according to claim 7, a client which is a terminal that moves in a mobile network, and a plurality of edges which are distributed in the network to distribute contents to the client A routing system for selecting a communication path to a server, wherein the mobile network comprises a plurality of areas, and a first router for selecting the communication path and an area to which the client originally belongs. When the client does not exist in a certain home network, the content transmitted to the client is received and transferred to the client, and the movement information is received from the client,
A second router for transmitting the movement information of the client to the first router, and the first router is configured to select the communication path based on the movement information.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. The present invention is based on the conventional "In-Lin".
The e "request routing system is improved to be a request routing system applicable to mobile networks such as mobile IP networks.

A. Configuration of First Embodiment FIG. 1 is a concept showing a request routing system of a first invention (when a client adds its own movement information to a transfer request such as an HTTP header) according to the first embodiment of the present invention. It is a schematic diagram. In the figure, a client 1 is a mobile terminal that receives distribution of content. Hereinafter, consider the case where the client 1 moves from the home network to the external network. here,
The home network is an area to which the client 1 originally belongs, and the external network is an area to which the client 1 moves. The IP address (home address) of the client 1's home network is (192.168.1.100), and the IP address (care-of address) of the external network.
Is (192.168.2.1). The combination of the home address and the care-of address is called a binding cache, and the home agent 5 (described later) sends H
It is sent to the TTP content router 4 (described later).

The edge servers 3a and 3b are servers that deliver contents to the client 1. The edge server 3a exists in the home network, and the edge server 3b exists in the external network. The IP address of the edge server 3a is (192.168.1.
3). The IP address of the edge server 3b is (1
92.168.2.3) and its URL is "www.es2.
k ○ × △ .com ”.

The HTTP content router 4 is arranged on the Internet and is a router for selecting a communication path between the client 1 and the edge servers 3a and 3b. In this example, it is a network different from the mobile IP network (Internet). However, it may be located in any network. The HTTP content router 4 includes a mobile node list 30 in which a binding cache is recorded, each edge server 3a,
Edge server list 31 that records the IP address of 3b
And uses HTTP as a communication protocol to select a content distribution route from one of the edge servers 3a and 3b to the client 1. Where HT
The TP content router 4 selects a content distribution route based on the movement information of the client 1 added to the content distribution request (HTTP request) received from the client 1. The details will be described later.

The home agent 5 is a server existing in the home network and manages transmission / reception of data transmitted / received to / from the client 1 via the mobile IP network. Also, home agent 5
Acquires the movement information from the client as appropriate. In addition, the home agent automatically selects the shortest route as the communication route of the client in the home network (RO: Route Optimizatio)
n) should be supported.

B. Operation of First Embodiment Next, the operation of the request routing system will be described with reference to FIGS. 1 and 2. First, the client 1 inputs the URL of the content itself (for example, http: //www.es2.k○×Δ.com) using a Web browser or clicks a link in order to receive distribution of the desired content.

Then, the browser of the client 1 uses the HTTP request header field 5 shown in FIG.
The care-of address of the client 1 is added to 0. Here, the request header field 50 is HTTP.
Of the request, the address of the request, the sender address of the request (home address of the client 1), and HTTP control message.

The browser sets a care-of address field 51 in the HTTP request header field 50, and the care-of address is written therein.
Then, the browser transmits a packet having the request header field 50 as a header to the HTTP content router 4 as an HTTP request (reference numeral).

Upon receiving the HTTP request, the HTTP content router 4 refers to the request header field 50 to determine whether there is the care-of address field 51. If there is the care-of address field 51, the normal HT is set as the address of the client 1.
Request header field 50 of TP request
The care-of address written in the care-of address field 51 is prioritized instead of the home address written in, and the route selection relating to the transmission request of the client 1 is performed. That is, the HTTP content router 4
By referring to the content of the received HTTP request and the IP address of each edge server 3a, 3b recorded in the list in advance, the edge server 3b arranged in the vicinity of the care-of address of the client 1 is selected, and the edge A response including the address of the server 3b is transmitted to the client 1 (reference numeral).

The browser of the client 1 makes a content delivery request to the address of the edge server 3b based on the received response (reference numeral). The edge server 3b that has received this distribution request transmits the content related to the distribution request to the client 1 (reference numeral).

On the other hand, the HTTP content router 4 is
The home address and care-of address of the client 1 included in the received request header field 50 and the expiration date of these information are recorded in the mobile node list 30. Also, the HTTP content router 4 stores the mobile node list 30 in each edge server 3a, 3b.
Distribute to.

C. Configuration of Second Embodiment Next, the second invention according to the second embodiment of the present invention, that is,
The configuration of the request routing system in the case where the care-of address is not added to the HTTP request transmitted from the client 1 will be described with reference to FIGS. 3 and 4. Here, unlike the case of the first aspect of the invention, it is assumed that the client 1 does not have the function of providing the care-of address field 51 in the request header field 50. The present invention has an advantage that the conventional client can be used as it is. Therefore, as shown in FIG. 4, the request header field 50 does not include the care-of address of the client 1. The HTTP content router 4 (claim 4
In the mobile node list 30 (corresponding to the first router in the above), nothing is initially recorded regarding the movement information of the client 1.

D. Operation of Second Embodiment Next, the operation of the request routing system will be described. First, the client 1 inputs the URL (http: //www.es2.k○×Δ.com) of the content itself or clicks a link with a Web browser in order to receive the distribution of the content. Then, the browser of the client 1 sends the packet having the request header field 50, which does not include the care-of address, as a header to the HTT.
It is sent to the HTTP content router 4 as a request of P (reference sign ').

Upon receiving the HTTP request, the HTTP content router 4 refers to the request header field 50 to request the request header field 50.
Based on the home address of the client 1 included in, the route selection related to the transmission request of the client 1 is performed.
That is, the HTTP content router 4 compares the home address with the IP address of each of the edge servers 3a and 3b referenced from the edge server list 31. In the case of FIG. 3, the home address (192.168.1.100) of the client 1 matches the IP network address (“A.B.C.” in the IP address “A.B.C.D.”). The edge server 3a (address is "192.168.1.3") is the client 1
Is selected in the vicinity of and the response including the address of the edge server 3a is transmitted to the client 1 (reference sign ').

The browser of the client 1 makes a content distribution request to the edge server 3a based on the received response (reference numeral '), and the edge server 3a.
Sends the content to the client 1 (reference sign ').

Here, the home agent 5 (claim 4
(Corresponding to the second router in 1) manages the data transmitted to the client 1, so that the content of the data (data transmission source, transmission destination, etc.) can be known. Therefore, when the edge server 3a transmits the content to the client 1 with the code ', the home agent 5 knows that the client 1 is about to receive the content from the edge server 3a. Therefore, the home agent 5 performs a process of transmitting the latest movement information acquired from the client 1 to the content transmission source (edge server 3a) (reference numeral ').

The edge server 3a records the movement information received from the home agent 5 in the mobile node list 30. The recorded mobile node list 30 is H
It is delivered to the TTP content router 4 (code '),
From the HTTP content router 4 to another edge server 3
b (code ').

As a result, the care-of address indicating the current destination area of the client 1 is recorded in the mobile node list 30 of the HTTP content router 4, so that the client 1 is the latest one as in the first invention. You can receive the routing that reflects the care-of dress. That is, when the client 1 next time inputs the URL in order to receive the same content distribution, the browser of the client 1 displays the information similar to the code “HTT”.
It is sent to the HTTP content router 4 as a P request (reference numeral ").

Upon receiving the HTTP request, the HTTP content router 4 refers to the request header field 50 and the mobile node list 30 to which the new movement information is added as described above, and based on the care-of address, The route related to the transmission request of the client 1 is selected. That is, the HTTP content router 4 uses the care-of address of the client 1 and each edge server 3a, 3
By referring to the IP address of b, the edge server 3b arranged near the destination area of the client 1 is selected, and a response including the address as the HTTP response header 60 is transmitted to the client 1 (reference numeral). .

Based on the received response, the browser of the client 1 makes a content delivery request to the address of the edge server 3b (reference numeral "), and the edge server 3
b transmits the content to the client 1 (reference numeral ").

E. Operation of Third Embodiment Next, in the present invention, the HTTP content router 4
A procedure for performing routing to the mobile terminal and the fixed terminal will be described with reference to FIG. According to this routing procedure, the client 1 described in the above embodiment is
Not only when it is a mobile terminal but also when the client 1 is a fixed terminal, the route selection processing between the client 1 and the edge servers 3a and 3b is performed. This allows
The HTTP content router 4 can deliver the content not only to the mobile terminal but also to the client 1 of the fixed terminal from the edge server in the vicinity of the client 1.

First, the HTTP content router 4
The HTTP request is received from the client 1 (step S11), the request header field 50 of the HTTP request is referred to, and the care-of address
It is determined whether the field 51 exists (step S1)
2).

When it is determined in step S12 that there is the care-of address field 51, the HTTP content router 4 adds the source IP address of the IP packet including the HTTP request to the mobile node list 30 (step S13). The source IP address includes the destination address of the IP packet, the source address (home address of the client 1), and the care-of address of the source (client 1). After that, the HTTP content router 4 performs a route selection process based on the care-of address of the client 1 included in the source IP address (step S14).

On the other hand, if it is determined in step S12 that the care-of address field 51 does not exist, the HTTP content router 4 receives the I request including the received HTTP request.
It is determined whether the same address as the source IP address (home address or care-of address of the client 1) of the P packet is in the mobile node list 30 (step S).
15).

If "Yes" in the step S15, the HT
The TP content router 4 uses the home address included in the binding cache of the client 1 and H
It is determined whether the home address or the care-of address of the client 1 corresponding to the source IP address included in the TTP request is the same (step S16).

In the case of "Yes" in step S16, since the movement information (binding cache) for the client 1 exists, it is known that the client 1 is a mobile terminal. In this case, the HTTP content router 4 uses the source IP address (care-of address)
A route selection process is performed based on (step S14).

If "No" in the step S16, the HTT
The P-content router 4 sends a "binding warning message" for requesting the latest binding cache to the home agent 5 (step S18). After that, the HTTP content router 4 determines whether or not the binding update is received from the home agent (step S19). The binding update is update information of the binding cache. If “Yes” in the step S19, it is known that there is movement information of the client 1, that is, the client 1 is a mobile terminal. Therefore, HTTP content router 4
Determines whether the care-of address in the binding cache and the home address match (step S2).
0).

If "No" in the step S20, it is understood that the client 1 has moved from the home network to the external network. So, in this case, HTTP
The content router 4 performs a route selection process based on the care-of address of the client 1 included in the source IP address (step S14).

In the case of "No" in step S15, it is understood that the movement information of the client 1 is not in the mobile node list 30, so the HTTP content router 4
Judges that the client 1 is a fixed terminal, the HTT
A route selection process is performed based on the source IP address (home address of the client 1) of the P request IP packet (step S17).

If "Yes" in the step S20, it means that the client 1 is a mobile terminal but exists at the home address. Therefore, HTTP content
The router 4 performs a route selection process based on the source IP address (home address of the client 1) of the IP packet of the HTTP request (step S17).

Even if the edge server closest to the client is found as described above, the effect of the present invention cannot be sufficiently exerted unless the route of content transmission from the edge server to the client is optimum. For example, in FIG. 1, it refers to a problem in which the edge server is in the same area as the client but communicates with the client via another area. Therefore, it is preferable that the edge server support a route optimization extension function (RO: Route Optimization), that is, a route optimization function that automatically selects the shortest route as a communication route with a communication partner. This makes it possible to prevent the so-called edge server triangle problem.

The request in the above embodiment
Various processes may be executed by causing a computer system to read and execute a program for realizing the functions of the routing system.

[0046]

As is apparent from the above description, according to the present invention (first invention), when a client sends a content transfer request to a router, its own movement information is added to the transfer request. Therefore, the router can select the communication path between the client and the edge server based on the movement information of the client. Therefore, the router can select the communication route in consideration of the position of the client. For example, when the content related to the transfer request exists in a plurality of edge servers, the content is distributed from the edge server near the destination of the client. It becomes possible.

Further, according to the present invention (second invention), the second router which receives the movement information of the client transmits the movement information of the client to the first router, and the first router communicates based on the movement information. Since the route is selected, even if the client does not have the function of adding its own movement information to the transfer request, it is possible to select the communication route between the client and the edge server based on the movement information of the client. You can

[Brief description of drawings]

FIG. 1 is a conceptual schematic diagram showing a request routing system according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an HTTP request header field used in the above system.

FIG. 3 is a conceptual schematic diagram showing a request routing system according to a second embodiment of the present invention.

FIG. 4 is an explanatory diagram showing HTTP request header fields used in the above system.

FIG. 5 is a flowchart showing an operation of the request routing system according to the third exemplary embodiment of the present invention.

[Explanation of symbols]

1 client 3a, 3b Edge server 4 HTTP content router 5 Home Agent 30 mobile node list 31 Edge server list 50 request header fields 51 Care-of Address Field

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Takahito Yoshihara, inventor             2-15-1 Ohara, Kamifukuoka City, Saitama Stock             Company CAD Research Institute (72) Inventor Hironori Horiuchi             2-15-1 Ohara, Kamifukuoka City, Saitama Stock             Company CAD Research Institute F term (reference) 5K030 GA10 HA08 HB13 HC01 JT09                       LB05                 5K033 BA13 CC02 DA19 EC04                 5K067 AA15 DD23 EE02 EE10 EE16                       HH21 JJ35 JJ39

Claims (7)

[Claims] 1. A routing method for selecting a communication path between a client, which is a terminal that moves in a mobile network, and an edge server, which is distributed and distributed in the network and distributes contents to the client, When a router that selects a communication path is arranged, the client sends the transfer request to the router using the communication protocol used when transferring the content on the network, A routing method, characterized in that the router adds self-movement information, and the router selects the communication route based on the added movement information. 2. The routing method according to claim 1, wherein the communication protocol is a protocol for transferring data described in a predetermined description language. 3. The routing according to claim 1, wherein the mobile network comprises a plurality of areas, and the movement information of the client has an address in a movement destination area of the client. Method. 4. A routing method for selecting a communication path between a client, which is a terminal moving in a mobile network, and an edge server, which is distributed and distributed in the network and distributes contents to the client, The mobile network is composed of a plurality of areas, a first router for selecting the communication path is arranged, and a second router for receiving the movement information from the client in a home network, which is the area to which the client originally belongs. If the client is not present in the home network when it is arranged, the second router receives the packet transmitted to the client, transfers the packet to the client, and sends the packet to the first router. Sending the movement information of the client, The routing method, wherein the first router selects the communication route based on the received movement information. 5. The routing method according to claim 1, wherein the edge server automatically selects a shortest path as a communication path between the edge server and the client. 6. A routing system for selecting a communication path between a client, which is a terminal moving in a mobile network, and an edge server, which is distributed and distributed in the network and distributes contents to the client. Then, the client is provided with an addition unit that adds its own movement information to the transfer request when the client transmits the transfer request using a communication protocol used when the content is transferred on the network. A routing system comprising a router that selects the communication route based on the movement information. 7. A routing system for selecting a communication path between a client, which is a terminal that moves in a mobile network, and an edge server, which is distributed and distributed in the network and distributes contents to the client. The mobile network is composed of a plurality of areas, and when the client does not exist in the first router that selects the communication path and the home network that is the area to which the client originally belongs, the client is addressed to the client. A second router that receives the content transmitted to the client and transfers the content to the client, receives the movement information from the client, and sends the movement information of the client to the first router, The first router is configured to forward based on the movement information. Routing system, characterized in that consist of selecting a communication path.