Electrical computers and digital processing systems: multicomput – Computer-to-computer protocol implementing – Computer-to-computer data transfer regulating
Reexamination Certificate
1997-04-10
2001-02-13
Coulter, Kenneth R. (Department: 2758)
Electrical computers and digital processing systems: multicomput
Computer-to-computer protocol implementing
Computer-to-computer data transfer regulating
C709S231000
Reexamination Certificate
active
06189039
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention generally relates to data transmissions in computer networks and, in particular, to a method for selective streaming of data (e.g. video) using multiple transmission protocols.
2. Description of the Related Art
It is known in the prior art to “stream” data between different segments of a computer network. In a typical computer network environment, such as an enterprise intranet, data streaming may be carried out by delivering a separate stream for each user or by delivering a single stream to all users. The former technique effects point-to-point (P
2
P) communication or “unicasting” and is often implemented using the Internet Protocol (IP) unicast communications protocol. The latter technique effects point-to-multipoint (P
2
M) communication or“multicasting” and is often implemented using the IP multicast communications protocol. IP multicast is the most efficient of these transport mechanisms because only one copy of the data is propagated throughout the network. All systems that desire to receive the transmitted stream simply register with the network to receive the data.
Although IP multicast is the most desirable method of transmitting the data to several systems at once, it is sometimes not used. IP multicast may not be used due to technical limitations. For example, some network routers may not have the capability to support the protocol; alternatively, the available network bandwidth on some segments of the network may not have the capacity to handle streaming data traffic when it is not received by any end user on the segment. Even where the network segment may support IP multicast, a network administrator may elect not to activate it for performance reasons as multicasting does consume bandwidth. For these reasons, IP multicast is most commonly used in a highly-selective manner throughout the network.
It is also known in the art to use both IP multicast and IP unicast on the same intranet to transmit the same data. However, such techniques have a number of problems associated with them as well. First, a careful mix of IP multicast and IP unicast must be established that minimizes the amount of data being transmitted on the network. For example, if some users receive the data via IP multicast and others receive it via IP unicast, multiple copies of the data are transported out onto the network. This may or may not be the most efficient way to reach these systems, especially if many of the unicast streams are directed to systems on the same network segment. Another problem that arises from the combination of IP multicast and IP unicast on the same intranet is that the receiving application must be capable of handling both types of streams while minimizing the network traffic requirements.
The present invention is directed to solving these problems.
SUMMARY OF THE INVENTION
It is a primary object of this invention to minimize network traffic in a computer network by providing an efficient data streaming method.
It is another object of this invention to enhance the efficiency of data transport over a computer network using known unicasting and multicasting techniques.
It is still another object of this invention to use IP unicast and IP multicast protocols to stream the same data to multiple users in a computer network in a manner that minimizes network traffic.
It is yet another more general object of this invention to provide selective streaming of video data from a video server to end users in a computer network such as an enterprise intranet.
It is still another object of the invention to enhance bandwidth utilization in a computer network transparently to the end user.
Another general object of this invention is to enhance the transmission of video data streams across multiple segments of a computer network.
These and other objects of the invention are achieved through a technique of “selective” tunneling of streaming data from a server to a client in a computer network having one or more network “segments.” Thus, for example, a computer network is an enterprise intranet having a plurality of local area network segments. The server has a tunneler utility, and the client has a receiver utility. A repeater utility may also be running in each network segment. Typically, the tunneler utility receives an IP multicast signal and converts the signal to IP unicast format for delivery to an end user. According to the invention, the receiver utility running on the client machine first attempts to detect if a given data stream is available via IP multicast on the network segment supporting the client. If not, then the receiver utility issues a request for an IP unicast stream. This request is serviced by the tunneler utility. The tunneler utility re-broadcasts the IP multicast feed using IP unicast to send the data stream directly to the requesting user and/or to a repeater utility. The receiver utility then receives and processes the data stream for output to the end user. Alternatively, the receiver application, or a network administrator, launches the repeater utility, which then converts the IP unicast stream back to IP multicast format for re-broadcast over the network segment, so that other clients on the segment may receive it.
The foregoing has outlined some of the more pertinent objects and features of the present invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or modifying the invention as will be described. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the following Detailed Description of the Preferred Embodiment.
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Harvey John Paul
Kressin Mark Scott
Mills Richard Allen
Coulter Kenneth R.
Emile Volel
International Business Machines - Corporation
Judson David H.
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