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Communication time reduction for the systems that send commands from server to device over HTTP

IP.com Disclosure Number: IPCOM000010373D
Original Publication Date: 2002-Nov-22
Included in the Prior Art Database: 2002-Nov-22
Document File: 4 page(s) / 36K

Publishing Venue

IBM

Abstract

As number of pervasive devices with Internet access capability, such as mobile phones, PDA or home gateway are increasing, it is essential to manage those devices over the Internet for both service providers and device manufacturers. And better communication throughput is one of the key requirement for the device management web application. This invention is a method for increasing communication throughput by incorporating full duplex and chunked encoding over existing HTTP protocol for the device management web applications.

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  Communication time reduction for the systems that send commands from server to device over HTTP

  For the web applications that manage the devices with Internet access capability, such as mobile phones or home gateway systems, remotely by sending commands from the servers, it is advantageous to use HTTP as the protocol between a server and the devices, for the following:

The device management agent program in a device is able to use existing HTTP protocol stacks for web browser. No additional network environment is necessary between the devices and the Internet. No global IP address is necessary for a device.

However, because of this communication method that transmit a command over an HTTP response from server and transmit a command result in a next HTTP request to server [Fig. 1], there are following problems in communication overhead.

Because most pervasive devices limit the size of its command, it is necessary to send

multiple HTTP requests to complete one device management job. For example, an IC card (Smart Card) limits the maximum command data size to 256 bytes. In wireless communications, the transmission delay is fairly large, compared to wired

communications. This means that the number of command affects communication overhead largely. For example, in PDC, which is the most popular portable telephone system in Japan, the transmission delay is about 100 to 200 milliseconds. Each HTTP command or HTTP response has HTTP header and this header size,


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which is usually 300 to 500 bytes, affects communication overhead.

Device

Device Mgt. Server

[Fig. 1] Original communication method

A newly invented communication method, HTTP full duplex communication method, that solves above overhead introduces two HTTP connections and performs receiving, processing and transmission of a command simultaneously, as described below with [Fig.

HTTP GET request

HTTP response

Device Command-1

Process

HTTP POST request

Device Response-1

HTTP response

Device Command-2

Process

HTTP POST request

Device Response-2


2].


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The device opens two HTTP connections for the server and transmits the first GET


2.

request using one of the HTTP connections. The server transmits an HTTP response with the multiple device commands that the


3.

server is able to transmit at a time. The device process a command when it is received while receiving body of an HTTP

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response. When the device completes processing the first command, the device transmits the

first command response in an HTTP POST request using another connection. The POST request utilizes the Chunked Transfer Encoding as defined in HTTP 1.1 [rfc2616]....