Electrical computers and digital processing systems: multicomput – Computer-to-computer data routing
Reexamination Certificate
1997-10-14
2001-05-29
Coulter, Kenneth R. (Department: 2154)
Electrical computers and digital processing systems: multicomput
Computer-to-computer data routing
C370S238000
Reexamination Certificate
active
06240462
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to a method for providing enhanced quality of service for networks, and more particularly to a method for providing enhanced quality of service for a client device that accesses a network via a single connection to a Point Of Presence server.
Many users connect to the Internet, also known as “world wide web”, via a switched communication line coupled to a dial-up modem. As used herein the term Internet refers to a large distributed network comprised of interconnected processors (servers) and routers wherein data passes through several routers, before reaching its intended destination (e.g., an applications server). For Internet access devices, such as a personal computer or so-called “web television” device, the entry point to the Internet is usually a Point Of Presence (POP) terminal server. From the POP terminal server, the user of the device can access any applications server in the network.
Today, many users are attempting to transfer to their web access devices, large amounts of data or files, such as Hyper Text Markup Language (HTML) text, graphics or animated image files using formats such as, Graphics Interchange Format (GIF) files, real time audio files or multimedia (video and audio) files. These files are typically very large, bit-intensive files. As used herein the term “download” refers to a file transfer from the applications server through the Internet or other large distributed network, to the POP terminal server and from the POP terminal server to the user.
One of Internet users' most common complaints is the delay experienced by dial-up modem Internet users in their attempt to download bit-intensive files to their web access devices. The aforementioned delay is sometimes so severe that the process of downloading audio and video information is frustrating to the point that dial-up modem Internet users end up terminating the process before most of the file is downloaded. In summary, almost all Internet access providers are unable to guarantee to their subscribers a given (QOS) Quality of Service (i.e., performance requirement for delivery of data within a given time window).
In response to this problem, many solutions have been proposed to guarantee a given QOS for Internet service. For example, some systems engineers have suggested that timely data delivery over the Internet can be achieved by significantly increasing the bandwidth of the links in the shared IP backbone. Unfortunately, even an over-engineered Internet backbone may not result in smooth transfers of real-time information (e.g., audio and video) due to the inherent nature of the IP protocol itself which allows only “best effort” attempts at data delivery.
Another technique for solving the delays inherent in transferring data from an applications server to a web access device involves the use of an additional, separate plain old telephone service (POTS) circuit-switched connection to couple the applications server to the web access device. While useful, this technique requires a user to have two individual telephone lines and two separate modems, both of which being available at once. Unfortunately, most users do not have this capability. Thus, a problem of the prior art is the lack of an efficient, cost-effective and practical method for significantly reducing delay over a connection that couples a web access device to an applications server.
SUMMARY OF THE INVENTION
We have realized that for a connection that couples a web access device to an applications server via a POP terminal server, the leg of the connection that extends from the web access device to the POP terminal server is more often than not congestion-free while the leg of the connection that couples the POP terminal server to the applications server is prone to heavy traffic density that causes intolerable delay for large file transfer.
The present invention is directed to a method and a system for quicker transfer of information from an applications server to a web access device. The quicker information transfer is accomplished by bypassing the typically congested IP backbone to establish a separate connection that extends from the applications server to a Point Of Presence (POP) terminal server that is coupled to the web access device. The connection may be for example, a circuit switched ISDN connection associated with another network that is logically separated from the backbone of the IP network. Other alternate paths for such a connection include a logical communications path within an Asynchronous Transfer Mode (ATM) network with QOS feature, a logical communications path within another IP network that is RSVP-enabled internally between routers, a link within a Frame Relay network, or simply a communications path within any other packet-switched or circuit-switched network that may be less congested.
According to a feature of the present invention the request and data paths are separated within the network so that there are two distinct unidirectional paths, one from the Point Of Presence (POP) terminal server to the web applications server via the IP backbone using IP protocols, and the other path being, for example, a circuit-switched ISDN connection coupling the applications server to the POP terminal server.
According to one embodiment of the present invention, an applications server to which a query is directed by a web access device, communicates with a Generalized Address Resolution Protocol Server (GARPS) resident within the IP network to determine the optimum path for downloading requested data to a particular POP terminal server. The GARPS maps IP addresses to a subnet address, which is a combination of a selected subnetwork (POTS, ISDN, ATM, RSVP network, etc.) and the address within that network for the machine identified by the IP address. According to the present invention, any device on the network can use the GARPS find out the best subnet to choose when setting up a QOS path to another device.
According to another feature of the present invention, the optimum subnet is chosen based on several key factors, such as: a) the ability to support the QOS desired by the user on that network; b) the current traffic load on that subnetwork; c) the price/payment that the user is willing to pay for that service; and d) the time of day variations that the subnetworks experience.
According to yet another feature of the present invention, the optimum subnet will be made available by the GARPSes, and its identity will be stored in a database that will be dynamically updated based on the above criterion. In the event that none of the alternate subnets are available, the default IP backbone network would be used.
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David Lewis et al.; Multi-Service Management in a Multi-Provider Environment; Fifth IEE Conference on Telecommunications; pp. 292-296, 1995.
Agraharam Sanjay
DeSimone Antonio
Kuthyar Ashok K.
Ramamurthy Ram S.
Sibal Sandeep
AT&T
Coulter Kenneth R.
Kenyon & Kenyon
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