Electrical computers and digital processing systems: multicomput – Computer-to-computer protocol implementing – Computer-to-computer data framing
Reexamination Certificate
1998-09-28
2001-07-24
Luu, Le Hien (Department: 2152)
Electrical computers and digital processing systems: multicomput
Computer-to-computer protocol implementing
Computer-to-computer data framing
C370S431000, C709S230000, C709S232000
Reexamination Certificate
active
06266702
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates generally to communication networks and more particularly to a method and system for communication with a network.
BACKGROUND OF THE INVENTION
Communication devices such as telephones, computers, and video equipment may be interconnected to form a network. A network allows multiple parties to communicate with each other. Communications within a network often take the form of voice, data, video, or a combination of these forms. Such communications allow for meetings and presentations with participants separated by long distances These events depend on the network to function as quickly and accurately as possible, in order to compensate for the distance of the participants.
A network may be formed by linking independent communication devices together according to a protocol. One example of a protocol for linking communication devices is Fibre Channel. In a Fibre Channel network, each device, acting as a node, or entry point onto the network, transmits and receives information through the network to the other network nodes. Although Fibre Channel networks may take various forms, a loop topology is often incorporated. In a loop topology, network nodes are connected in loop arrangement with any given node directly connected to only its two neighbors. In this manner, communication between all parties connected to the network is possible. One advantage of the some loop topologies is fault tolerance. In some implementations that utilize counter-rotational rings, if a break between nodes occurs, information may be routed back around the loop to its destination.
Information transmitted by the nodes travels around the loop until it reaches its destination. Traditionally, many Fibre Channel networks are configured to allow transmission of information by only one node at a given time. Thus, while any given node is transmitting information, all other nodes can only receive information In addition traditional networking protocols do not specify the amount of time that this one node can transmit. Such communication schemes pose problems with the transmission of isochronous data that require the transfer of data at regular intervals such as live video and audio. A node that has live video to transfer is threatened with data loss if the network is currently servicing an unbounded transfer for another node. This problem is enhanced when the network has multiple sources of live isochronous data.
Such problems may be addressed by periodically transmitting, around a network, a plurality of frames each including a plurality of slots for inserting information into or extracting information from the frame. When transmitting such frames it is desirable to limit the ability of certain nodes to read certain information stored in the frames as well limit the ability of certain nodes to write information to the frames. Such limiting provides security for information that is not intended to be available to all users of a network.
SUMMARY OF THE INVENTION
Accordingly, a need has arisen for an improved method and system for network communication. The present invention provides a method and system for communication information in a network that addresses shortcomings of prior systems and methods.
According to one embodiment of the invention, a method for extracting information from and inserting information into a frame that is transmitted between a plurality of nodes includes determining the type of the transmitted frame. The method also includes generating an access table in response to determining the type of the transmitted frame. The access table indicates, for each node, which slots the node can write data to and from which slots the node can read data from. The method also includes reading data from a first slot as the first slot arrives at a node if the access table indicates the node can read from the first slot. The method also includes writing data from a node to a second slot as the second slot arrives at the node if the access table indicates the node can write to the second slot.
According to another embodiment of the invention, an insertion and extraction apparatus for inserting into and extracting data values from a frame transmitted to a plurality of nodes is provided. The frame has a plurality of slots for storing data. The insertion and extraction unit includes an access table indicating which slots from which at least one of the plurality of nodes may extract information and also indicating which slots into which at least one of the plurality of nodes may insert information. The insertion and extraction unit also includes an extraction and insertion map control unit operable to control modifications to the access table and an extraction control unit operable to provide data stored in one of the plurality of slots to a respective node indicated by the access table. the insertion and extraction unit also includes an insertion control unit operable to provide data to one of the plurality of slots from a respective node indicated by the access table.
Embodiments of the invention provide numerous technical advantages. For example, in one embodiment of the invention, selective access is provided to portions of frames of data based on the type of frame. Therefore, data may be extracted from or written to selected portions of a frame that is transmitted synchronously between a plurality of nodes, including nodes that do not have read or write access to relevant slots of the frames. This enables synchronous transfer of information between nodes in a network even when more than one node is originating data at the same time. This ability is particularly advantageous in applications such as video conferencing where multiple parties transmit information simultaneously and such transmission requires synchronization.
Other technical advantages are readily apparent to one skilled in the art from the following figures, descriptions, and claims.
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Darnell B. Scott
Jennings William T.
Lengel Bradley D.
Reddy Praveen S.
Baker & Botts L.L.P.
Jaroenchonwanit Bunjob
Luu Le Hien
Raytheon Company
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