Cisco Technology, Inc.

Symantec Operating Corporation

Google Inc.

Guenter E Roeck

Mark E Millet

Wei-Sing Chen

Feisal Y Daruwalla

Sunil Khaunte

James R Forster

Charles J Naegeli

Chrisanto Leano

Joanna Qun Zang

John T Chapman

Michael R Thomas

Richard Woundy

Serge Shats

Yong Lu

Joseph O'Donnell

Peter H Hochschild

Son Truong Nguyen

William B May, Jr

Hain-Ching Liu

Robert Edman Felderman

Serge Pashenkov

Roy Michael Bannon

Kartik S Chandran

James Clark

John K Chen

Nan Tu

Son D Nguyen

Sameer Lokray

Anil K Chandiramani

Robert M Haragan, Jr

Derek J Brown

Joseph C H Fung

Yuzon Hao

A protection CMTS is available to immediately service a cable modem should that modem's service from a working CMTS fail for any reason. To speed the service transfer (cutover) from the working CMTS to the protection CMTS, the cable modem may preregister with the protection CMTS well before the cutover becomes necessary. The cable modem's registration with both the working CMTS and the protection CMTS preferably employs a single IP address, so that the cable modem need not obtain a new IP address during cutover. While the cable modem may register with both the working CMTS and the protection CMTS, the devices are designed or configured so that only the working CMTS injects a host route for the cable modem into the appropriate routing protocol. Only after cutover to the protection CMTS does the protection CMTS inject its host route.

Method for a cable modem to rapidly switch to a backup CMTS

A method, apparatus, and queuing engine implement congestion management. The method may include receiving, via a first interface of the apparatus, data traffic for forwarding to a node of a network. The method may also include receiving, at a second interface of the apparatus, a notification that indicates that congestion is affecting communication with the node, and responsive to the notification, accumulating the data traffic into the queue for a given time period. The method may further include dequeuing the data traffic from the queue after the given time period; and sending the portion of the data traffic to the node via the second interface.

Method and apparatus for a network queuing engine and congestion management gateway

A system, method, and computer-accessible medium are disclosed for identifying in-line synchronization instructions in binary program code. One or more executable segments of the binary program code may be scanned to identify one or more potential in-line synchronization instructions. For each potential in-line synchronization instruction, it may be determined whether neighboring potential instructions are valid instructions. For each potential in-line synchronization instruction, it may be determined that the potential in-line synchronization instruction is a valid in-line synchronization instruction if the neighboring potential instructions are valid instructions.

System and method for detecting in-line synchronization primitives in binary applications

A network device communicates in a cable network. The network device has a port to allow the device to communicate on a cable network. The network device also has a processor to send a message indicating that the device is assuming a dormant state. The processor then assumes a dormant state for the device, releasing the service identifiers and service flows associated with that device for use in the cable network.

Increasing the number of supported devices on a DOCSIS interface

Routing protocol based redundancy design for shared-access networks

A system, method, and computer-accessible medium for logging and replaying asynchronous events are disclosed. One or more asynchronous events occurring during execution of a first instance of a computer program are logged. In logging the asynchronous events, a respective location in the execution of the first instance at which each of the one or more asynchronous events occurs is determined. A respective synchronous event preceding each asynchronous event is also determined. The asynchronous events are replayed during execution of a second instance of the computer program. In replaying each asynchronous event, the second instance is instrumented at the respective location during the execution of the second instance after detecting the preceding synchronous event.

System and method for logging and replaying asynchronous events

A system, method, and computer-accessible medium are disclosed for efficient generation of application snapshots. Execution of an application is stopped, wherein a plurality of memory pages are accessible to the application. By altering page permissions of the plurality of memory pages, a state of the plurality of memory pages is preserved while the execution of the application is stopped. The execution of the application may be restarted after the state of the plurality of memory pages has been preserved. The state of the plurality of memory pages may be captured after the execution of the application has been restarted.

System and method for efficient generation of application snapshots

A system, method, and computer-accessible medium for modifying user memory from an arbitrary kernel state are disclosed. The kernel may generate a modification to the context of the process. Subsequently, the kernel may pass control to the process in user mode, and further, the process may pass control from the user mode to the kernel in response to the modification of the context of the process. The kernel may then modify the process memory from kernel mode.

System and method for modifying user memory from an arbitrary kernel state

Apparatus, methods, and computer program products for detecting or locating a viable data carrier in a downstream channel by a cable modem. Potential channels for data carriers can be eliminated quickly by going through a 'screening' process, i.e., the first constellation diagram match, thereby preventing those potential channels from going through a significantly more time-consuming second constellation match. The determination of whether the signal in the potential channel is modulated according to the first particular modulation scheme is done rapidly and only potential channels containing a signal likely to be modulated according to the second particular modulation scheme are examined for the second determination step.

Fast and reliable data carrier detection by a cable modem in a cable television plant

A time-based buffering system buffers data based upon how long the data should be held in order to comply with a traffic shaping policy. The data's source or destination need not be considered in determining where to buffer the data. The time-based buffering system includes a collection of time-based queues, each of which has a different time to dequeue. The system controlling traffic shaping determines how long a particular piece of data should be buffered (a 'traffic shaping delay') until it can be put on the network. Then, based upon that length of time, the system chooses one of the time-based of queues in which to buffer the data. That chosen queue has a dequeuing time that matches the traffic shaping delay. After the chosen queue dequeues its contents (at the specified time), it assumes a new dequeing time and is free to buffer new data that must be delayed by a time matching the new dequeuing time.

Network traffic shaping using time-based queues

Methods, systems, and computer program products are disclosed for allowing rapid re-provisioning of a cable modem at the MAC/physical layer in a cable modem network. After a cable modem goes through power-up/self-test, i.e., a hard boot, and goes through initial provisioning, the modem is in a steady state in which standard DOCSIS periodic ranging is performed. It is during periodic ranging that the provisioning status, such as bit rate, ISP, etc., can be rapidly changed to allow for 'on the fly' changes in provisioning. A cable modem is synchronized with the cable modem network. The modem is then provisioned once it receives a configuration file from a provisioning system. Periodic ranging is then performed between the modem and the CMTS, located either in a headend or a fiber node in the cable plant. The periodic ranging is interrupted by a command or action taken by the CMTS on the cable modem instead of the modem being affected directly by the provisioning system. Once periodic ranging is broken, either by cessation of polling messages or a ranging abort command, the modem goes directly to re-synchronizing with the cable network and re-provisions, i.e., avoids performing a power-on/self test or hard boot.

Rapid cable modem re-provisioning in a cable network

A system for testing a cable network during normal operation interleaves test signals with live data traffic. Installed cable modems are used to generate the test signals. During live communication, such modems send upstream data at allotted time periods. Periodically, there are time slots when no modem is transmitting on the network. During these times, specific modems may be directed to transmit specific test signals. A controller such as a cable modem termination system directs specific modems to transmit signals at defined frequencies and powers during specific time slots. In this manner, the system can monitor the frequency response of the cable network at various locations, and thereby determine 'on-the-fly' when maintenance or modification is required.

Cable plant certification procedure using cable modems

Methods, apparatus, and computer-readable media are disclosed for performing diagnostic tests of a communication link between a headend and a cable modem without having to assign an IP address to the cable modem. The diagnostic tests are performed at the MAC layer and test the state of the hardware between and including the cable modem termination system (CMTS) and a selected cable modem. By doing so, a network operator is able to more easily focus in on a potential problem in cable RF/MAC connectivity between the two components by first eliminating (or identifying) a problem with hardware before focusing on problem-solving at the software level, typically at the Network layer, at which point the cable modem is assigned an IP address.

Media access layer ping protocol for diagnosing cable modem links

A CMTS redundancy technique requires at least two CMTS interfaces (e.g., line cards) on one or more CMTS chassis at the head end of a cable network. One of the CMTSs serves as a backup or 'protecting' CMTS. When another CMTS (a 'working' CMTS) becomes unavailable to service its group of cable modems, the protecting CMTS takes over service to those cable modems. The SWITCHOVER takes place transparently (or nearly transparently) to the cable modems. The protecting CMTS provides service on the same downstream channel as used by the working CMTS. The cable modems need not modify any settings pursuant to their cable modem communication protocol (e.g., DOCSIS ranging). This transparency to the cable modems is realized by keeping the working and protecting CMTSs in synchronization regarding service parameters for the cable modems. In other words, the protecting CMTS maintains a list of current parameters for allowing service to the cable modems.

Cable network redundancy architecture

Disclosed is an apparatus and method for simulating a plurality of cable modems for testing a device, such as a head end complex. In general terms, the present invention provides a multiple cable modem simulator and techniques for setting up and executing the same. In one implementation, the multiple cable modems are simulated by simulating multiple MAC (media access control) state machines for multiple cable modems. In other embodiments, a simulator of the present invention includes a mechanism for simulating physical operating conditions of the simulated cable modems. For example, even when the simulator is located at a single test location, different distances and power levels may be simulated for the different simulated cable modems.

Growing community of inventors

San Jose, CA, United States of America

Guenter E Roeck