Cisco Technology, Inc.

Sudhakar Mamillapalli

Stephen Paul Belair

David Delano Ward

Robert Charles Monsen

Matthew F Williams

Xiaoyi Liu

Stephan P Belair

Satisha K Bhat

Venkatasiva Mortala

Satisha Bhat

Matthew Williams

Disclosed are various ways of performing reliable multicast communication which may include, for example, designating which node or nodes to acknowledge a message and/or whether to immediately acknowledge or delay acknowledgement of a message, which may be of particular use with routers, packet switching systems, computer systems, and other devices. Multiple nodes are typically sent a multicast message, which includes an indication of one or more designated nodes to acknowledge the message, a sequence number or other message identification value, and possibly an indication whether an immediate or delayed acknowledgment is requested. A node receiving the message responds accordingly if it is designated to acknowledge the message, which may include requesting any missing messages, and/or sending an acknowledgment message for the messages it has received since it sent its last acknowledgment message.

Reliable multicast communication

Disclosed are mechanisms for initiating and performing tasks by a gang of members. A member of a gang identifies an event or other condition which requires notification to and/or action to be taken by at least a subset, if not all the other members of the gang. The gang member notifies other gang members by sending a message, such as that using reliable group communication using multicast and/or unicast messages. The information notified to other gang members and/or actions to be performed are extensible to meet the needs of the wide-variety of possible applications. A small list of example subject areas of these applications includes collecting, distributing, updating, responding to, and/or other processing of error conditions, routing information (e.g., between systems, from a route processor to line cards within a system, etc.), configuration information, flow control information, statistics or other values, etc.

Gang scheduling among one or more components or systems

A method is disclosed for providing likely updates to views of group members in unstable group communication systems. A group message is received from a sender associated with a sending node in a network. The group message includes a message view having a counter and an acknowledgment set. The acknowledgment set identifies one or more receiving nodes to which the group message is directed. Issuance of an acknowledgment of the group message to the sending node is deferred. The group message is delivered to the receiving nodes. An acknowledgment of the message is received from one of the receiving nodes. The message view is updated by removing each receiving node that issues an acknowledgment from the acknowledgement set. The updated message view is provided to the sender.

Method and apparatus for providing likely updates to views of group members in unstable group communication systems

A method and apparatus for protecting secured files stored on a file system employs a file security status associated with each file to signal whether or not access to the file is allowed. The file security status is stored in a fixed location in memory. Upon opening the associated file, the file security status is copied to a second location in memory. Depending upon the file security status stored in the second location, operations on the file by a client are either allowed or denied. Operations on non-secure files are always allowed. Operations on secured files are allowed only after verification of the client's authorization to access the file and the subsequent modification of the file security status stored in the second memory location. The method protects secured files from deletion by unauthorized clients. This is accomplished by, upon opening a secure file, initializing a third memory location to a value indicating that the file will not be deleted upon closing. This value may be changed by an authorized client only after going through the above-described verification process. Once the value has been changed to reflect that the file should be deleted when closed, the file will be deleted when closed. A method for creating a new secure file is also provided.

Method and apparatus for securing information access

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San Jose, CA, United States of America

Sudhakar Mamillapalli