Method of autonomic representative selection in local area networks

A method and apparatus for selecting a client computer as a relay server to rebroadcast common application information that is broadcast from a server system over a network. The client computer is selected randomly to rebroadcast the User Datagram Protocol (UDP) information received from the server system and client computers receiving the UDP information from another client computer relay server on the network do not rebroadcast the information. If the client computer selected to rebroadcast the common information fails to rebroadcast, another client computer is randomly selected as a relay server and takes over rebroadcasting the common information.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to networking methods and systems, and more particularly, to networking methods and systems for autonomic representative selection of a client computer for broadcasting server common information in local area networks.

2. Background and Related Art

In networking systems, it is sometimes necessary for a server to send common information to a plurality of clients in the connected network. Examples of such information may be “call waiting” information as generated at call centers. For example, call centers produce waiting queues for handling customer call loads. “Call waiting” information may include the number of waiting customers and queue ids. Such information continually changes and must be provided to the call takers manning client workstations so as to effectively manage the call center operation.

One technique for sending common information to is to use what is known as a UDP (User Datagram Protocol) broadcast of the information from the server to client workstations. However, in a WAN there is often the possibility within the network that network equipment is incapable or unable to carry out a UDP broadcast. For example, there may be routers in the network that block data transmission for security reasons.

To overcome such possibility, network designs have been configured to enable each client to use TCP communications and to independently make a request for the required information from the server. Alternatively, a broadcast server may be used within a segment of the WAN, such as, a LAN but such an arrangement typically increases costs.

SUMMARY OF THE PRESENT INVENTION

In accordance with the embodiments of the present invention, a method and system is provided for automatically determining or selecting one client workstation as a relay server for broadcasting in a network segment, using broadcast processing on the network. Client workstations in a network segment to which they belong, i.e. within the range where broadcast is possible, act in competition with one another to carry out broadcast processing within the segment. Only the winner of the competition continues broadcasting. If an error or default occurs in the winner, the competition starts over again, and another winner is found from among the remaining workstations to carry out broadcasting.

Embodiments of the invention are generally directed network systems and methods employing UDP broadcasting of information from a server to clients over a network wherein, through autonomic selection, a single client within a segment of the network undertakes broadcast processing within the segment, acting as a relay server. This single client, acting as a relay server, communicates with the central server to obtain application data for rebroadcasting to the other clients within the segment.

Where the selected rebroadcasting client fails, for some reason, to rebroadcast, a new client is automatically selected from within the segment to rebroadcast the datagram information from the server. Typically, as used herein, the term “rebroadcasting” is used to describe client computer broadcasting of server system UDP broadcast information. The term “broadcasting” or “broadcast” is typically used to describe UDP information broadcast by the server.

According to one embodiment of the invention, there is provided a method of broadcasting common information over a computer network, comprising the steps of:broadcasting said common information from a network server to a plurality of network clients for possible rebroadcasting to the other clients of said plurality of clients;selecting from among said plurality of clients at least one such client to rebroadcast said common information to the remaining clients; andcausing each of the remaining clients to block rebroadcasting from the client when said at least one such client is selected to rebroadcast said common information to said remaining clients.

The above method further comprises the step wherein broadcasting said common information to said plurality of clients is broadcast using user datagram protocol.

The above method comprises the further step wherein said at least one client selected from among said plurality of clients to rebroadcast said common information is selected from among said plurality of clients by randomly assigning different fixed time intervals for each client to rebroadcast said common information.

The above method further comprises the step wherein the client randomly assigned the shortest time interval for rebroadcasting is selected from among said plurality of clients for rebroadcasting said common information.

The above method further includes the step wherein failure of said client selected from among said plurality of clients to rebroadcast said common information causes another client to be selected from among said plurality of clients to take over rebroadcasting said common information to the remaining plurality of clients within said network.

The above method also includes the step wherein the client of said plurality of clients first receiving said common information from said server within a predetermined fixed cycle of time after failure is selected for rebroadcasting from among said plurality of clients for continuing rebroadcast of said common information.

The above method still further includes the step wherein said predetermined fixed cycle of time occurs at different times for each client of said plurality of clients.

According to another embodiment of the invention there is provided a network communication method, comprising the steps of:broadcasting common information using user datagram protocol from a server to a plurality of network clients;randomly selecting at least one of said network clients as a relay server to rebroadcast to said common information to the plurality of clients not selected; andblocking the rebroadcasting of said common information in each of said plurality of clients not selected.

According to still another embodiment of the invention there is provided a network system, comprising:a network server arranged to broadcast common information to clients;a plurality of clients connected to said server through said network to receive said broadcast common information;each of said plurality of clients arranged to rebroadcast said common information; andeach of said plurality of clients provided with a different fixed time interval for rebroadcasting said common information with said client with the shortest fixed time interval selected from said plurality of clients connected to said network as a relay server to rebroadcast said common information to the remaining ones of said plurality of clients.

The above network system embodiments further include:the network system wherein failure of the client selected from among the plurality of clients to rebroadcast said common information acts to cause another client to be selected to take over rebroadcasting common information to the remaining plurality of clients after receiving said common information from said server;the network system wherein said another client selected to take over rebroadcasting is the first client to receive said common information from said server within a completed fixed cycle of time;the network system wherein said fixed cycle of time is the same for each of said plurality of clients and occurs at different times for each of said plurality of clients; andthe network system wherein said server broadcasts said common information to said clients using user datagram protocol.

A further embodiment includes a client system embodiment, comprising:processor apparatus having input means for receiving user datagram information;processor apparatus having output means for rebroadcasting said user datagram information;processor control apparatus for determining whether said user datagram information is received from another client system; andprocessor control apparatus for inhibiting rebroadcasting where said datagram is received from another client system.

Client system embodiments further include:processor control apparatus for controlling the rebroadcast of said user datagram information when said user datagram information received on said input means is not received from another client system;the client system wherein said rebroadcasting occurs periodically at over fixed time intervals with the fixed time intervals determined randomly; andthe client system wherein said processor control apparatus rebroadcasts said user datagram information when said client system fails to receive said user datagram information from another client within a fixed cycle of time.

Another embodiment of the invention provides a program storage device readable by a computer machine, tangibly embodying a program of instructions executable by the machine to perform method step for causing said computer machine to carry out decision making in client computer systems receiving broadcast information in a network, comprising:analyzing said broadcast information input signals to determine their source; andrebroadcasting said input signals when the input signals are received from a server computer until one of a plurality of client computers in said network is selected to rebroadcast said input signals to the remaining client computers.

Program storage embodiments also includes the steps of:selecting randomly said one of a plurality of client computers selected to rebroadcast said input signals;inhibiting the rebroadcasting of said input signals when said input signals are received from another client computer;the rebroadcasting said input signals periodically at a fixed time intervals with the fixed time interval determined randomly for each client computer;selecting one of a plurality of client computers to rebroadcast by identifying the client computer with the shortest fixed time interval for rebroadcasting;commencing rebroadcasting of said input signals from said server computer when said selected client fails to provide rebroadcast input signals; andthe rebroadcasting of input signals from said server computer when said selected client fails is carried out until another server computer of said plurality of server computers is randomly selected.

Further embodiments are described in the appended dependent claims.

Further aspects of the invention will now be described, by way of preferred implementation and examples.

DETAILED DESCRIPTION OF THE DRAWINGS

With reference toFIG. 1, there is shown a conceptual arrangement of a plurality of clients, two of which are shown broadcasting. Initially, when a server broadcasts information, all clients receive and rebroadcast the broadcast information from a server. This rebroadcast by the clients is carried out in their own segment, i.e. the area to be reached by broadcasting packets or broadcast address.

Broadcast information is typically common information to be used by all of the clients within a broadcast segment. The segment may be a local area network (LAN) or larger than the LAN or a subset of the LAN. The common information may be broadcast to any of a number of segments but for purposes of description of the invention, reference will be made to clients in a network within a segment.

Broadcast information may be sent using a variety of protocols but in accordance with the present invention, common broadcast information is sent using User Datagram Protocol (UDP).

Conventional UDP is a connectionless oriented protocol that uses an Internet Protocol (IP) address for the destination host or client and a port number to identify the destination application. Thus, the UDP process involves a transport layer that sits on top of the base IP to transmit a datagram that comprise header information and the data or information inself.

In accordance with the present invention, a modified UDP process is employed to ensure that all clients within a segment, i.e. a “plurality” of clients computers, receive the UDP transmitted broadcast information from the server. This is done by electing one of the client computers as a relay server to rebroadcast the server UDP transmitted broadcast information. Each client computer determines from the rebroadcast information, whether the information comes from the server or another client computer selected to rebroadcast the information. If it determines that the broadcast information is from another server, it stops rebroadcasting. If the client computer selected for rebroadcasting fails to rebroadcast the information, another client computer takes over the rebroadcast of information from the server. The terms “client”, “client computer”, “client workstation”, “client system” are used interchangeably and are intended to mean clients in a network arrangement as is understood by those skilled in the art.

FIG. 2shows a network diagram of a typical network topology arrangement. Server1acts to send UDP information over gateway3to Wide Area Network (WAN)5. Gateway7, in turn, receives the information from WAN5to send to a plurality of clients computers via bus10. The computers are shown here as PCs9and PCs11with PCs9connected to bus10and PCs11connected to bus12. Bus12is connected to bus10through router13. Client computers may be any of a variety of computer arrangement but PCs are shown here. Similarly, Server1may be any of a variety of well known and commercially available computer arrangements configured to act as a network server to manage network resources.

FIG. 3shows a block diagram of an example of a client computer system arrangement, which system arrangement could include, among other arrangements, a PC arrangement. As shown, the client computer system includes apparatus, such as, a Network Interface Card15for interfacing the computer system Bus17to the network. Also, included is Integrated Device Electronics (IDE) controller18for connecting Hard Disk Drive (HDD) storage device19and compact disk (CD) storage ROM device21to bus17.

FIG. 4depicts general flow diagrams of how the “Broadcaster” thread and “Listener” thread interact. The listing thread in the client computer acts to “receive data”, as shown by block41, and informs the “Broadcaster” thread of having received data, as shown by block43and dotted line45. If the “Listener” thread receives data, as determined at block47, the process “waits” for a predetermined or “given period of time”, as shown at block49. After a predetermined period of time, the process loop back to block47and if no data has been received after the predetermined period of time, the process then acts to “broadcast data”, as shown by block50, as received from the broadcast server.

The block diagram ofFIG. 5represents the manner in which the client computer systems in the network each operate to carry out the processing required to listen to rebroadcast the common information sent by network server. Network Communication, represented by block51, acts to send and receive information or data from network interface apparatus, such as, Network Interface Card15, as shown inFIG. 3. Listener block53represents the operation of receiving information from the Network Communication block51and changes the status of the Process Status Store function, as represented by block55. Process Status Store acts to store process status which are the Listener53status and Broadcaster57status.

The Data Store function, as represented by block59, acts to store in memory the UDP broadcast application information or data as received from the server computer to be rebroadcast by the Broadcaster57operation. Broadcaster57sends the information to be rebroadcast to Network Communication51operation. Broadcaster57also acts to change the status of Process Status Store55.

Data retrieving, as carried out by the Data Retrieving operation, represented by block61, retrieves application data, i.e., the UDP broadcast information from the server computer and stores it in Data Store59memory. If the operation of Listener block53receives rebroadcast information from another client computer by checking the status of process status store55, the data retrieving operation will do nothing, i.e., sleep. Data Displaying device63displays the information received by the Listener block53.

The operation of Listener block53in client computers is shown in more detail in the flow chart represented inFIG. 6. The process starts at block65which leads to the instruction to “wait for data receiving from Network Communication block”, which is block51inFIG. 5. The decision “does the data come from another system”, as represented by block69, is then made. This query determines if the data or information received comes from a rebroadcast by a client computer system in the network segment or comes from the network server. This determination is made from the IP address and port number of the received information.

Where the information is determined to come from another client computer system, “the listening status in Process Status Store block”55, shown inFIG. 5, is “set”, as shown by the step of block71inFIG. 6. The data is then sent to Data Displaying apparatus, such as a monitor, as shown by block63inFIG. 5. This step is represented by block73inFIG. 6. Where the data is determined by block69to not come from another client computer system, the process returns directly to block67to wait for data coming from Network Communication block51shown inFIG. 5.

As used herein the terms “data” and “information” are employed interchangeably meaning that which is received and transmitted by the network clients and network server. “Broadcast information” is used to identify information broadcast by the network server. “Rebroadcast information” is used to identify information received from the server and resent in broadcast manner by a selected client computer or computers acting as a relay server to the other client computers in the network segment.

FIGS. 7A and 7Bshow a flow chart for the operation of the “broadcaster” operation shown by Broadcaster block57inFIG. 5. The broadcaster operation starts at block75wherein an instruction “to wait for the time ‘t1’” is given, as shown in block77. Time “t1”, is a given parameter of a fixed period of time. After time “t1,”, an instruction to “check the status in ‘Process Status Store’ block”55inFIG. 5is given. This instruction is shown by block79inFIG. 7Aand the instruction acts to determine if “the listen status” in the “Process Status Store block” is “set” or “cleared”, as shown by block81.

If the “listen status” in “Process Status Store” block is “cleared” indicating that the received data does not come from another client computer, the process goes to the instruction in block83inFIG. 7Bwherein “the current time as ‘tc0’” is obtained and set. In addition, as stated in the next block85, the instruction is given, to “set the broadcast status in ‘Process Status Store’ block”55, shown inFIG. 5, thus indicating that data will be rebroadcast by this client computer. Then, an instruction is given, as shown is block87ofFIG. 7Bto “Get data from ‘Data Store’ block and send it to ‘Network Comm.’ block. Thus, as shown inFIG. 5, data in Data Store block59, as retrieved by Data Retrieving block61from the network broadcasting server, is sent to Network Communication block51to broadcast over the network.

As further shown inFIG. 7B, the next step, as shown by block89, is to “Calculate fraction time ‘tr’, with random number and time ‘tr0’”. In this regard “tr,” is a random number whose range is 0<=tr<tr0with tr0a given parameter.

With fraction time “tr” calculated, the next instruction, shown in block91ofFIG. 7B, is to “Get the current time as ‘tc1’” and “Wait for the time “t2−tc0+tc1+tr′”. The time “t2” is also a given parameter with “t2” being less than “wait” time “t1”, another given parameter. The time “−tc0+tc1” represents the width of the pulse from Broadcaster57. After waiting for the time “t2−tc0+tc1+tr”, the process returns to the block79instruction to “Check the status in ‘Process Status Store’ block”.

Again, with respect toFIG. 7A, if this the “listen status” of block81is “set”, meaning the data comes from another client computer, the instructions “Clear the listen status in ‘Process Status Store’ block” and “Clear the broadcast status in ‘Process Status Store” block “are carried out, as shown by block93. After these clearing instructions, the process waits according to the instructions to “Wait for the time ‘t1’”, as shown in block95. After waiting for the time “t1” the process returns the instruction “Check the status in ‘Process Status Store’ block”, as shown by block79.

Thus, if the “listen status” of block81is “cleared”, meaning the received data did not come from another client system, the process waits a time “t2−tco+tc1+tr” to broadcast with trbeing a random number and then checks the ‘Process Status Store’ block79. If the “listen status” status of block81is “set”, meaning the received data came from a client computer, the process waits a given or fixed time “t1” and then checks “Process Status Store” block79. Where the “listen status” is “set”, the “broadcast status” in “Process Status Store” block55(FIG. 5) is “cleared” by the instruction of block93inFIG. 7A. Where the “listen status” is “cleared”, the “broadcast status” in “Process Status Store” block55is “set” by the instruction of block85inFIG. 7Bsince the client computer did not receive the received data from another client computer and is in the process of broadcasting over the network, as shown in block87.

With reference toFIG. 8, there is shown a process for carrying out the operation of “Data Retrieving” block61inFIG. 5. The process starts at block97wherein an instruction is given to “check the status in ‘Process Status Store’ block” (block55inFIG. 5). A determination is then made in block101as to whether the “broadcast status” is “set” or “cleared”. If “set”, indicating that the client computer is in the process of sending data, an instruction is given by block to “Communicate With A Server Via ‘Network Comm.’ Block to get Application Data”, as shown by block103.

After communicating with a server to obtain application data, the data is “set” to “Data Store” block59inFIG. 5by the instruction “Set to ‘Data Store’ block” shown by block105inFIG. 8. The process then waits for a time “t1” before checking the status in “Process Status Store” block55inFIG. 5. This instruction to “wait” is shown by block107inFIG. 8. Thus, the process then waits for a time “t1”, before checking the status in “Process Status Store” block55.

FIGS. 9 and 10show timing diagrams representing the manner in which the client computers interrelate with one another in carry out rebroadcasting network data. Although reference is made inFIGS. 9 and 10to PC's as client computers, it is understood that the reference is by way of example and that operation would be the same for any type of client computer.

FIG. 9shows the manner in which 3 PCs interact to converge to a leader to do the rebroadcasting of Server Application Data. Initially, all client computers, such as PCs, start rebroadcasting Server Application Data. The “Listener” operation, shown in block53inFIG. 5, is “set” for each client computer since all client computers receive data from another system. This is shown by block71inFIG. 6. Thus, each client computer operates to “listen” and “rebroadcast” at different fixed time intervals “t′2”.

The time fixed interval “t2′” is equal to “t2”+“tr” where “t2” is a fixed number and “tr” a random number. Thus, each client computer has a different fixed time interval “t′2” as determined by “tr”. As shown inFIGS. 9 and 10, the period of each “t′2” starts from the left edge of the Broadcaster pulse. However, the actual “waiting” period starts at the right edge of the Broadcaster pulse. Thus, the “waiting” period, as shown inFIG. 7B, is “t2−tc0+tc1+tr” with “+tc1−tc0” being the pulse width.

Since each client computer generates its own rebroadcast time “t′2” randomly and thus has a different duration fixed time interval “t′2”, each client computer rebroadcasts at different times. Since the listening status is “set” for all client computers, all client computers wait the fixed cyclic time period t1, which time period is the same fixed time period for each client computer. Since each client computer process rebroadcasts at different times “t′2”, then each client computer begins the fixed “wait” time period t1from a different point in time. Thus, as can be seen inFIG. 9, the client computer processes are not synchronized. The client computer with the shortest rebroadcast time interval for “t′2” emerges as the one selected to take over rebroadcasting network server broadcast data since it is the first to complete a full fixed time interval “t1”. Thus, PC2is selected since it has the shortest time interval “t′2”, as shown at point C inFIG. 9.

FIG. 10shows the manner in which one client computer takes over after a client computer previously selected to rebroadcast server data fails, for some reason, to rebroadcast the data. As shown, PC1is the client computer previously selected to rebroadcast server data. The rebroadcast stops, as shown at point A, for any of a variety of reasons. Since the rebroadcast from PC1stops, then PC2and PC3wait time “t1” before rebroadcasting. As shown inFIG. 10, since PC3becomes the first PC to complete the fixed time interval cycle “t1”, then PC3takes over rebroadcasting server application data. As previously noted, these fixed interval cycle times “t1” are carried out after the random “t′2” broadcast cycle times, and thus occur at different times.