KR19990024691A - Proxy server function structure and control method - Google Patents

Abstract

The present invention relates to a proxy server function in a TDX-10 ISDN internet subsystem and a method of controlling the same. The present invention relates to a method for realizing and controlling a proxy server function in a previously developed TDX-10 ISDN internet access system. By realizing the proxy server function in the switching system, it is not only easier to control than the proxy server of the external connection type, but also the traffic related to the control is reduced, and the service request can be quickly processed. Therefore, the quality of service can be improved in terms of delay time, and it can be a base technology for realizing other Internet server functions such as mail server, mirror server, and file transfer server as internal functions of exchange system.

Description

Proxy server function structure and control method

The present invention relates to a proxy server function implementation and control method in the TDX-10 ISDN Internet subsystem.

Recently, the number of Internet subscribers is exploding all over the world, and the demands of clients, who are Internet subscribers accessing the Internet server, are naturally increasing in the Internet network based on the client-server model.

Therefore, it is necessary to expand the processing capacity of the Internet server such as bandwidth of the Internet network, processing time of the server, storage device, and the like to satisfy the increasing needs of subscribers.

To solve this problem, it is necessary to expand the internet network facilities or improve the processing capacity of the Internet server.

However, as the cost is increased, an alternative is needed to satisfy the needs of the Internet subscribers at low cost.

In other words, by installing a proxy server on the Internet network and placing cache memory therein, it reduces the overall traffic on the Internet network and responds to the demands of the Internet subscribers. Can be reduced.

In general, a proxy server is a special purpose server that operates on a firewall system of an Internet network. The proxy server is a proxy server for each protocol in a client application such as a web browser such as Netscape Navigator or MicroSoft Explorer. If specified, all subsequent requests will be processed by the proxy so that the subscriber can receive the necessary information.

When a request for cached information occurs when a copy of frequently accessed information is taken from a remote server and the processing time is faster than disk or memory, i.e. placed in the cache, immediately from the cache to the client. To increase efficiency.

The pros and cons of using a proxy server are:

The advantage is that the response time for the request is significantly reduced because the information cached in the local proxy server is accessed without being routed directly to the remote server. As a result, the overall Internet network load and Internet server load are reduced compared to the case where the route to the remote server is to be routed, and the client can obtain cached information even when the remote Internet server is not running.

In addition, a disadvantage is that a new device called a proxy server system must be added in addition to the existing system, and management problems arise, and cache operation problems such as cache content matching and cache deletion problems occur.

On the other hand, the following technical issues are currently being studied about how to manage the cache, which is the main function of the proxy server.

First, with regard to maintaining the consistency of cache information, there is a substantial difficulty in ensuring complete correspondence between the cache information of the proxy server and the cache information of the remote server.

The information consistency problem of updating the proxy server's cache information immediately by reflecting the change of the remote server information can be solved by setting the time to live (TTL) function, client polling function, and invalidation protocol. protocol).

The survival time setting function sets the time value for which certain time information stored in the proxy server's cache is valid, and when the client requests the information, the TTL setting function value of this information is expired. This is how to get the information back to the remote server.

Proper setting of the TTL value is an important issue, which can be effectively applied to information that is updated at regular intervals, such as articles from newspapers or broadcasting stations.

In addition, the client polling function is a method in which a client periodically polls a remote server to check whether information stored in a proxy server's cache is valid, that is, whether or not there is a change.

This method also matters how to set the polling period.

The next invalidation protocol is a way for the remote server to notify the proxy server that the cache information of the proxy server is invalid whenever its information is changed.

Therefore, the remote server must know which proxy server has a copy of the information it provides.

In addition, when the cache information is deleted, the proxy server's cache has a finite size, and when the request for information that does not exist is received from the client, the proxy server receives the information from the remote server and receives one of the existing cache information. You should delete the above information and save the newly received information.

In this case, the question of which information is deleted is First-In, First-Out (FIFO), which deletes the oldest information first, and Least-Recently Used (first), which deletes the most recently used information first. LRU) and Least-Frequently Used (LFU) policies, which are deletion policies according to frequency of use, are used.

In addition, the issue of when to execute such deletion policy should be solved, such as deleting when new information is received from a remote server, deleting at regular intervals, or using a combination of the two. have.

The next multiple proxy server functions become a bottleneck in the connection to the proxy server as the number of clients requesting information from the proxy server increases.

To solve this problem, it is necessary to have several proxy servers and to link them together to share information with each other.

However, the method of having multiple proxy servers has a problem that additional functions and procedures including multicasting functions may be increased, and thus may be inefficient.

1 is a block diagram illustrating a communication method between a subscriber and a proxy server in a conventional internet network. The network includes a sub-network 10 in which an internet subscriber 11, a proxy server 12, and a local cache 13 are connected to each other. It is composed of a remote server 20 is connected to the proxy server 12 of the send and receive responses.

If an application program on the Internet subscriber terminal, for example, does not have a proxy server set in a web browser, a request message is delivered to the server through forwarding and routing, and a response message thereof is received.

The service is realized through the same process as the transmission process of the existing Internet Protocol (hereinafter referred to as IP) datagram.

If the proxy server 12 is set, the service is realized through the following procedure.

When a request arrives from the Internet subscriber 11 to the server management module in the proxy server, the server management module uses the protocol specified in the Unified Resource Locator (URL) as the key in the information of the request message. Identifies the application protocol that made the request.

The server management module then retrieves the requested information, typically whether the document is stored in a local cache.

If the requested information exists, the corresponding information in the cache 13 is transmitted to the requesting subscriber. If the requested information does not exist, the information is requested to the remote server 20 corresponding to the application protocol.

When the remote server sends the requested information to the proxy server, the proxy server 12 receives the information and stores it in the local cache 13, while sending it to the subscriber in a response message.

The above procedure describes only basic processing procedures. In addition, the proxy server function includes a cache management function such as maintaining consistency of cache information and deleting cache information.

In order to solve the above problems, an object of the present invention is to implement a proxy server function in an internet subsystem developed for processing Internet traffic in a public network switching system.

1 is a configuration diagram of a communication method between a subscriber and a proxy server in a conventional Internet network;

2 is a configuration diagram of a TDX-10 ISDN Internet access exchange system to which the present invention is applied;

3 is a block diagram of a proxy server control procedure in the TDX-10 ISDN Internet access exchange system according to the present invention;

4 is a configuration diagram of a cache table managed by a proxy server according to the present invention;

Explanation of symbols for main parts of the drawings

10: subnetwork 11: Internet subscribers

12: proxy server 13: local cache

20,60: Remote Server 30: TDX-10 ISDN Internet Subsystem

31: time switch 32: subscriber interface board

33: large interprocessor communication network

34: trunk / routing interface board

35: time switch processor 36: subscriber interface processor

37: trunk interface processor

38: interprocessor communication network 39: matched exchange processor

40: Subscriber 50: Internet Service Provider Router

201: Information (file) name 202: IP address of remote server

203: information (file) position 204: information survival time

205: access frequency 206: recent access time

In order to achieve the above object, the present invention provides a processor for processing an Internet service call connection request, a matching exchange processor that is responsible for setting up a call between an calling subscriber and an Internet service provider through an ITU-T Q.931 signaling procedure, and an Internet service. Subscriber interface processor that manages the switch information and Internet address information for each Internet subscriber for the subscriber interface for transmitting the Internet protocol datagram, and a large-capacity processor for transmitting IP datagram and relay line management function connected to the ISP And a trunk interface processor performing a function of connecting to a communication network, and a large processor-to-processor communication network for transmitting the Internet traffic at high speed.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram of a TDX-10 ISDN Internet access exchange system 30 to which the present invention is applied, wherein the Internet subscriber processing subsystem includes an integrated service digital network (registered service) registered in the Internet data access service of a public network exchange system. When the Internet service call connection request is received from the subscriber 40, the call processing procedure and the point-to-point protocol are performed to establish a data transmission path between the Internet service providers (hereinafter referred to as ISPs) connected to the switching system. (Point-to-Point Protocol, hereinafter referred to as PPP) is used to assign an IP address to the calling subscriber to control the Internet Protocol (Internet Protocol) datagram transmission.

In the TDX-10-ISDN public network switching system, the Internet subsystem for Internet traffic processing is implemented as a single subsystem. The main components and functions of the processor and the internal communication network are as follows.

An Access Switching Processor for Internet traffic (ASP_INT) 39 is a processor that handles Internet service call access and uses the ITU-T Q.931 signaling procedure to establish a path between a calling subscriber and an ISP. It is in charge of setting up.

The operation is started by an internet call attempt from the number translation block of the digital subscriber processing subsystem, and becomes a counterpart of the calling party call control block to perform a function corresponding to the called party call control block.

It performs the function of allocating switch system switch information for internet subscriber interface and notifying to internet subscriber interface.

It is also the main processor in charge of overall control functions such as releasing switch resources of the switching system when a call is released.

Subscriber Interface Processor (SIP) 36 manages switch information and Internet address information to each Internet subscriber for a subscriber interface for the Internet service, and performs a function of transmitting IP datagrams substantially. .

It is responsible for assigning the Internet address to the calling subscriber through connection with the calling subscriber through the PPP protocol, which is a two-layer protocol.

After that, it performs the function of transmitting the IP datagram transmitted from the originating subscriber through the communication between the large-capacity processors, and the software block corresponding to the proxy server function is mounted.

Also, a trunk interface processor (hereinafter referred to as TIP) 37 performs a relay line (T1 / E1) management function connected to an ISP and a function of connecting to a large interprocessor communication network for transmitting an IP datagram.

Initially, the connection from the switching system to the ISP router is via a serial interface of the switching system via a RS-232 or V.35 cable (Data Service Unit / High Speed Modem / Channel Service Unit, hereinafter referred to as DSU / HSM /). CSU), and the circuit termination device is connected to the circuit termination device and the router on the ISP side through a dedicated line (4-wire cable).

The high-capacity inter-processor communication network (hereinafter referred to as HIPCN) 33 is an inter-processor communication network having a high transmission speed of 400 Mbps, and the Internet traffic is transferred to an inter-processor communication network of an existing public network switching system. The communication network (hereinafter referred to as IPCN) 38 is insufficient for the processor, and is an interprocessor communication network for transmitting Internet traffic such as data, audio, and video at high speed by increasing the transmission speed.

3 is a configuration diagram of a proxy server control procedure in a TDX-10 ISDN Internet access exchange system according to the present invention. First, a system to be operated as a proxy server is connected to a TDX-10 ISDN Internet access exchange system, which is also a proxy server. It means that it can work.

However, it is common to configure the Internet server so that only the server functions.

A call connection request is sent from the subscriber via an ISDN digital link of 64 Kbps to an Access Switching Processor (hereinafter referred to as an ASP), and the number translation of the called party is transferred by the Number Translation Processor (hereinafter referred to as NTP). The number translation proves the Internet name.

The time switch processor (hereinafter referred to as TSP) and the space switch processor (hereinafter referred to as SSP) allocate time and space switch resources inside the TDX-10 ISDN switching system (101).

As the result of the number translation, the Internet call is found, and transmits an Internet Call Setup message to the Internet subsystem in the TDX-10 ISDN exchange system (102).

Internet call processing An incoming call procedure is performed to an access signaling processor for Internet (ASP). ASP_INT transmits an Internet call setup request message to a subscriber interface processor (103).

After receiving an Internet call setup request message, the SIP in the Internet subsystem performs a Point-to-Point Protocol connection procedure (PPP Connection) for transmitting and receiving Internet Protocol datagrams.

During the PPP connection procedure, the subscriber is assigned an IP address (104) to operate as an Internet host.

In the subscriber station which has been assigned an IP address and can operate as an Internet host, if a proxy is set, a proxy server connection (HTTP Request) is requested (105).

Upon receiving the proxy server connection request, the SIP checks its cache table as shown in FIG. 4 and if the requested information exists (106), transmits the information to the subscriber (107).

If the requested information does not exist in its cache table, the information should be transmitted to the remote server through the information procedure.

First of all, it is necessary to identify which protocol the information requested from the subscriber is. The URL (Unified Resource Locator) information in the received Hyper Text Transfer Protocol (hereinafter referred to as HTTP) request message is used as a key. To distinguish the application protocol (108).

The SIP determines a corresponding protocol and transmits an information request message to a trunk interface processor (hereinafter referred to as TIP) for routing to the corresponding remote server (109).

The router of the Internet service provider receiving the information request from the TDX-10 ISDN Internet subsystem (110) obtains the requested information from the remote server (110) using a communication protocol with an existing server.

Appropriate information corresponding to the subscriber's request from the remote server is received via the ISP (112), via the TIP in the TDX-10 ISDN Internet subsystem (113), and up to the SIP (114).

The SIP stores new information received from the remote server in its cache table (115) and then transmits the information to the subscriber.

If the same information is requested by the subscriber after the transmission, then the information stored in the cache table can be provided immediately (116).

4 is a configuration diagram of a cache table managed by a proxy server according to the present invention. When the proxy server receives a proxy request message (HTTP Request) from an Internet subscriber, the proxy server refers to the cache table to determine whether the requested information is stored in the cache. If the requested information does not exist, the request message is routed to the remote server.

4 is a newly proposed cache table. The contents of the table include information or file name 201 which is a key for referring to the requested information, IP address 202 of the remote server which is the original location of the information, The time to live of the information used to manage the cached information (204), the access frequency (205) indicating how much the information is accessed by the Internet subscriber, and the information It consists of the last access time (206) indicating when it was accessed.

In addition, a memory address 203 that stores information is actually included to respond to the information.

In the cache table of FIG. 4, a remote server having an IP address of 123.222.101.10 receives kif-or.html information and stores it in a cache. The information is stored in cache memory address addresses 03F0 to 03F5.

The survival time of this information is 24 hours, which means that this information will be deleted.

This information also means that all of the information was accessed by Internet subscribers seven times, with the most recently accessed date at 1:25 pm on June 6, 1997.

As described above, the present invention implements the existing proxy server function in the TDX-10 switching system, so that not only the control is easier but also the traffic related to the control is reduced compared to the method of having a proxy server in the form of an external connection. In addition, since the service request is processed quickly, the quality of service (QoS) can be improved in terms of delay time.

The embedding technology of the proxy server function presented through the present invention is based on realizing other Internet server functions such as a mail server, a mirror server, a transfer server, and the like as an internal function of a switching system. Has the effect of becoming a technology.

Claims (3)

In the implementation of the proxy server function in the Internet subsystem for processing Internet traffic in public network switching system, A processor for handling an Internet service call connection request, the matching exchange processor in charge of establishing a call between an calling subscriber and an Internet service provider through an ITU-T Q.931 signaling procedure; A subscriber interface processor which manages switch information and Internet address information for each Internet subscriber for the subscriber interface for the Internet service, transmits an Internet protocol datagram, and is in charge of a proxy server function; A trunk interface processor for accessing a trunk line management function connected to the ISP and a communication between a large-capacity processor network for transmitting an IP datagram; Proxy server function structure comprising a large interprocessor communication network for transmitting the Internet traffic at high speed. The method of claim 1, wherein the subscriber interface processor Assigns an Internet address to the calling subscriber through a connection with the calling subscriber through the PPP protocol, which is a two-layer protocol, After assigning internet address, IP datagram transmitted from originating subscriber is transmitted through large interprocessor network. A proxy server function structure comprising a software block corresponding to a proxy server function. Based on the components of claim 1, a matching exchange processor for setting up a call between the calling subscriber and the Internet service provider, a subscriber interface processor for transmitting Internet protocol datagrams, and a function for connecting to a communication network between high-capacity processors In controlling a proxy server in a TDX-10 ISDN Internet subsystem having a trunk interface processor to perform and a large interprocessor network for transmitting Internet traffic at high speed, A first step of requesting connection to a proxy server if a proxy is set in a subscriber station capable of operating as an Internet host by allocating an Internet protocol address; Receiving the proxy connection, the SIP checks its cache table and, if the requested information exists, transmits the information to the subscriber; If the requested information does not exist in its own cache table, a third step of identifying which protocol the requested information is for and identifying the application protocol by using the URL information in the received HTTP request message as a key; Determining, by the SIP, a corresponding protocol, transmitting an information request message to a trunk interface processor, and routing to a corresponding remote server; A router of an internet service provider having received a request for information from the TDX-10 ISDN internet subsystem, a fifth step of obtaining the requested information from a remote server using a communication protocol with an existing server; A sixth step of receiving, from the remote server, the appropriate information corresponding to the subscriber's request via the ISP router via SIP in the TDX-10 ISDN Internet subsystem to the SIP; SIP has a seventh step of storing the new information received from the remote server in its own cache table, and transmitting the information to the subscriber.