Cisco Technology, Inc.

De Fu Li

Pawel Piotr Sowinski

Robert Goguen

James An

Hang Jin

Mark E Millet

Tong Liu

Hemant Singh

Xuan Wang

Chrisanto Leano

Jie Meng

John Skrobko

Yong Lu

Nathan Richmond Melhorn

Hui Sun

Nicos Achilleoudis

Keil Brewer

Jingfeng Zhang

Gary M Lewis

Wenwen Dong

John J Downey

Lu Yong

Robert J Goguen

James S An

Chrisanto D Leano

Presented herein are techniques for detection and avoidance of interference in a telecommunications network. In one example, a cable modem termination system (CMTS) is configured to receive upstream traffic from a plurality of cable modems. The CMTS detects collision characteristics resulting from substantially simultaneous transmissions from different combinations of the cable modems. Based on the detected collision characteristics, the CMTS designates/identifies collision groups for each of a plurality of the cable modems. After designation of the collision groups, the CMTS schedules upstream transmissions by the plurality of cable modems such that cable modems within the same collision group do not transmit within a same time frame and such that two or more cable modems that are not within the same collision group may transmit within a same time frame.

Interference detection and avoidance in a telecommunication network

One embodiment of the invention includes a coax media converter (CMC) system communicatively coupled to at least one modem in a network system. The system includes a frequency reference configured to generate a clock signal in a local time domain. The system also includes a scheduling processor configured to extract a bandwidth allocation message from a data stream and to re-stamp each of at least one timestamp in the bandwidth allocation message in the local time domain based on the clock signal to generate a corresponding updated bandwidth allocation message comprising a respective at least one re-stamped timestamp. The system further includes a downstream physical interface configured to transmit the updated bandwidth allocation message to the at least one modem to schedule upstream burst transmissions from the respective at least modem based on the at least one re-stamped timestamp.

Network system time domain re-stamping

Disclosed are apparatus and methods for managing upstream channels on a per cable modem basis. In certain embodiments, one or more thresholds are defined for each of a plurality of upstream logical channels of a headend system for receiving data from a plurality of cable modems (or other types of access nodes). Each defined threshold corresponds to a measurable parameter of the corresponding upstream logical channel. One or more metrics are collected for each cable modem of each upstream logical channel. It is determined whether to downgrade a selected cable modem to a selected one of the logical channels that has a lower performance level than the selected cable modem's current logical channel. Such downgrade determination is based on whether the selected cable modem's collected one or more metrics have failed a condition of the one or more defined thresholds and whether a percentage of a total of the cable modems of such current logical channel that have failed a condition for the one or more defined thresholds is less than a predefined percentage level. The selected cable modem is then caused to move from the current logical channel to the selected logical channel when the percentage of the total cable modems that have failed is below a predefined level if such selected logical channel is available. Otherwise, the current logical channel's modulation profile may be altered when the percentage of the total cable modems that have failed is above (or equal to) the predefined level.

Apparatus and methods for moving cable modems between upstream channels

In one embodiment, a Cable Modem Termination System (CMTS) generates a bandwidth grant message corresponding to a time segment. The CMTS identifies a portion of the time segment to be assigned according to received bandwidth request messages originating from downstream cable modems. The CMTS determines whether a remaining portion of the time segment can accommodate more than N broadcast contention slots, and if so, selects at least one of the cable modems for receiving an upstream bandwidth boost.

CMTS upstream channel bandwidth scheduler

In one embodiment, a first ranging timing description describing at least a duration of time during which a subject cable modem (CM) may burst and a duration of time during which the subject CM and other CMs in a multiple access network are not permitted to burst is translated into a second ranging timing description describing a duration during which a burst from the subject CM is expected to be received by a cable modem termination system (CMTS). The CMTS is conditioned to receive a burst from the subject CM during the duration of time described by the second ranging timing description. A timing offset is determined from at least an actual time a burst from the subject CM is received by the CMTS and the duration of time during which the subject CM and other CMs in the multiple access network are not permitted to burst to produce a determined timing offset. The determined timing offset is reported to compensate for delay in the multiple access network and the subject CM.

Modem timing offset compensation for line card redundancy failover

In one embodiment a technique is disclosed for facilitating communication between nodes and a head end of an access network including a head end, at least one shared access upstream channel and at least one downstream channel. A first insertion rate estimate is determined. In at least one embodiment, the first insertion rate estimate may relate to an estimated number of nodes attempting to sign-on to the access network during one or more time interval(s). In at least one embodiment, a frequency of occurrence of initial maintenance opportunities available to a first plurality of network nodes may be dynamically adjusted, for example, using data relating to the first insertion rate estimate. According to one embodiment where the access network corresponds to a cable network, the head end of the cable network may be operable to sign on at least 40,000 cable modems within a time interval of not more than 300 seconds.

Node registration technique implemented in access networks

A method for reducing Internet bandwidth used for data transfer between an originating modem and an answering modem over a VoIP connection is provided. Idle data received from the originating modem is detected by an Internet node. The Internet node does not forward the detected received idle data over the VoIP connection. To keep the modem connection between the originating modem and the answering modem alive, the Internet node regenerates idle data and transmits the regenerated idle data to the answering modem upon detecting no data received for forwarding to the answering modem.

Modem activity detection

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Wayland, MA, United States of America

De Fu Li