3com Corporation

Cisco Technology, Inc.

3com Ireland

William Paul Sherer

Glenn William Connery

Danny M Nessett

Vipin Kumar Jain

John F Hickey

Richard S Reid

David R Brown

Eugene O'Neill

Anne G O'Connell

Chi-Lie Wang

Peter Si-Sheng Wang

Tadhg Creedon

Sandeep Arvindkumar Patel

Howard W Johnson

Vincent Gavin

Ismail Dalgic

Hoi-tauw Jozef Chou

Wen-Tsung Tang

Andrew Palfreyman

Richard A Gahan

Lai-Chin Lo

John Hickey

J R Rivers

Richard Gahan

In one embodiment, a network device analyzes an encoded stream to identify a timing value included in a packet before a splice point. Next, the device determines a difference between identified timing value and a timing value included in a packet of the encoded segment to be spliced. In conjunction with splicing, the network device formats timing values of packets according to the determined difference, which improves play out of the spliced stream.

Restamping transport streams to avoid vertical rolls

A network transmitter (driver or adaptor/driver combination) reorders packets received for transmission from a higher layer protocol based on packet destinations. The invention reduces bottlenecks at the transmitter and potentially throughout network intermediate system. Destination based reordering may be accomplished through alternative methods, some alternatives taking into account the order at which packets to different destinations are queued by a higher layer protocol.

Network adaptor driver with destination based ordering

An intermediate system authenticates using cryptography. The authentication routine requires a user to supply a secret known only to the user before allowing data to be transmitted. The secret is never transmitted. The invention may be incorporated into an intermediate system, into intermediate system software, or into application specific integrated circuits designed for use in an intermediate system. The invention may include components that interact specifically with installed components in an end system or elsewhere in a network.

Method and apparatus for providing security in a star network connection using public key cryptography

A network adaptor that generates interrupts to a host system when data is received from the network or downloaded from system memory for transmittal over the network. The adaptor generates interrupts after a delay determined by an interrupt deferral mechanism, which includes one or more timers and/or one or more counters. Interrupts are generated, for example, after a predetermined time has elapsed after a DMA completion or after a certain number of packets are counted.

Network and adaptor with time-based and packet number based interrupt

Apparatus for controlling data flow using lookup tables to link incoming

An improved computer network and network device uses characteristics of prior art shared network protocols to control the flow of data and access to the network among a group of transmitting nodes. The invention determines which nodes wish to send data when a collision occurs by detecting and recording which nodes participated in a collision. A scheduling routine is designed to give each connected node a chance to send. A transmission control mechanism is used to prevent a subset of transmitters from transmitting while allowing one ES to transmit without experiencing a collision. The invention has a number of applications including within an improved ethernet repeater in a multimedia ethernet.

Method and apparatus for controlling latency and jitter in shared

A network intermediate system authenticates end systems attached to ports of the intermediate system. An authentication routine is called on a port each time an intermediate system detects any interruption in the physical connection with the port, including reboot of the end system connected to the port. Network data is not fully transmitted or received to any port that has not been authenticated. The invention distributes a user authentication to the point where an end system initially connects to a network, to prevent an authorized reception or transmission of network data that is not prevented under existing network login systems. The invention may be incorporated into an intermediate system, into intermediate system software, or into applications specific integrated circuits designed for use in an intermediate system. The invention may include components that interact specifically with installed components in an end system or elsewhere in a network.

Method and apparatus for authentication process of a star or hub network

A system provides for establishing security in a network that include nodes having security functions operating in multiple protocol layers. Multiple network devices, such as remote access equipment, routers, switches, repeaters and network cards having security functions are configured to contribute to implementation of distributed firewall functions in the network. By distributing firewall functionality throughout many layers of the network in a variety of network devices, a pervasive firewall is implemented. The pervasive, multilayer firewall includes a policy definition component that accepts policy data that defines how the firewall should behave. The policy definition component can be a centralized component, or a component that is distributed over the network. The multilayer firewall also includes a collection of network devices that are used to enforce the defined policy. The security functions operating in this collection of network devices across multiple protocol layers are coordinated by the policy definition component so that particular devices enforce that part of the policy pertinent to their part of the network.

Multilayer firewall system

A data pattern enforcer provides secure network communications at an adaptor layer by comparing transmitted and received packets to a set of rules to verify that said packets are appropriately being transmitted or received. The data pattern enforcer prevents application or other software with access to an adaptor on a network from using the adaptor for packet sniffing or spoofing. In a specific embodiment, the data pattern enforcer verifies packets at the layer 2 adaptor level using a value bit vector (which may be alterable or may be preset to a value, including to zero), a count value, and a mask to compare to data found in packets.

Method and apparatus for providing secure network communications

A network transmitter schedules packets so that packets are transmitted to a host or group of hosts so as not to overload any particular part of the network. In an embodiment, the transmitter uses packet data structures with a schedule indication for packets placed in the queue so that an independently running adaptor may know when to remove packets from the queue and transmit them. In an alternative embodiment, packets are scheduled by setting a future interrupt for transmitting a packet or group of packets. In a further embodiment, packets are placed in temporal sets where a temporal set is a group of packets that can be transmitted in succession without violating the bandwidth limitations of any network segment.

Method and apparatus for time-based download control

A network transmitter (driver or adaptor/driver combination reorders packets received for transmission from a higher layer protocol based on packet destinations. The invention reduces bottlenecks at the transmitter and potentially throughout network intermediate system. Destination based reordering may be accomplished through alternative methods, some alternatives taking into account the order at which packets to different destinations are queued by a higher layer protocol.

Binary data is transmitted to a network physical layer from a media access controller as a series of multibit nibbles and is encoded into a multi-level data stream and split among a number of transmission channels, thereby reducing the signal frequency necessary to carry the data on each one of the transmission channels. The multi-level signal is then translated at a receiver back into a binary data stream. In a specific embodiment, the symbol transmission frequency on each of the transmission channels is at the same frequency as the nibble transfer rate between the media access controller and the physical layer.

Method and apparatus for synchronized transmission of data between a

An Ethernet network or other CSMA/CD network includes a hub that is modified to generate a jamming signal on a communication line when a packet received over that line is directed to an unavailable destination. The destination may be unavailable due to full transmit buffers, full receive buffers, or congestion in other parts of the hub architecture. Jamming is detected by the source node as a collision and causes retransmission of the packet from the source node. The decision to jam may include a determination of the packet's priority which may be determined based on the packet's destination or source address.

Method and apparatus for avoiding packet loss on a CSMA/CD-type local

An Ethernet network or other CSMA/CD network includes hub adaptors that are modified to provide a known bounded low maximum access latency. The modified adaptors maintain a state variable whose values indicates whether the last operation by the adaptor was a transmit or a receive. In the case where the last operation was a receive, the adaptor transmits a packet with a minimum or zero backoff and as an option with a reduced interpacket gap. In the case where the last operation was a transmit, the adaptor waits before transmitting a packet a period of time that allows the other node on the channel to transmit a packet if the other node has a packet to transmit.

Growing community of inventors

Sunnyvale, CA, United States of America

William Paul Sherer