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Method for optimal bandwidth allocation on cable networks Disclosure Number: IPCOM000021510D
Publication Date: 2004-Jan-21
Document File: 4 page(s) / 51K

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The Prior Art Database


Disclosed is a method for optimal bandwidth allocation on cable networks. Benefits include improved functionality and improved performance.

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Method for optimal bandwidth allocation on cable networks

Disclosed is a method for optimal bandwidth allocation on cable networks. Benefits include improved functionality and improved performance.


         With the onset of widespread usage of the Internet by consumers and businesses, requirements for the optimization of data transfer rates to the home or business have become increasingly important.

         One of the issues encountered in a cable modem (CM) data network concerns the situation where some channels are overloaded, and some channels are underloaded. Users connected via the overloaded channels experience performance degradation but are unable to change automatically to less-loaded channels.

         Any method that load-balances a cable data network benefits the users and the cable operator. The user experiences less performance degradation during peak-load times, while the cable operator avoids the expense related to installing additional bandwidth for coping with overloads.

         The set of specifications that govern cable-based data transfer systems is the Data Over Cable System Implementation Specification (DOCSIS) Version 1.1, released October 1, 2001. This specification defines the control and management functions that make up the protocol for Cable Modems and cable modem termination system (CMTS) communication.

         One of the commands available in DOCSIS is the downstream channel change (DCC). While the name indicates a downstream channel change, the command supports changing both (or either) the downstream or the upstream channels. The DOCSIS DCC command is complicated and hard to implement. It is generated by the CMTS and sent to the CM. DOCSIS does not include an equivalent command where the CM can send a command to the CMTS to request a change of its upstream channel. DOCSIS includes the assumption that load balancing should be performed by the CMTS because it has complete knowledge of number of clients (CMs), the available channels, and the current load on the network. For this reason, DOCSIS creators did not see a need for an equivalent command, initiated by the Cable Modem.

         Conventional methods for changing channels use the DOCSIS DCC command that enables the modem to move to another channel only if the CMTS instructs them to do so. However, the CMTS is only aware of past and current traffic to the CM and cannot predict future traffic. This means that load-balancing implemented from the CMTS side always makes some errors when moving CMs to new channels. CPU-controlled CMs are expected to enable future traffic prediction.

General description

         The disclosed method adds a control command to the protocol for CM-initiated upstream channel change (CM-UCC). The command enables a cable modem to signal its move from the current downstream/upstream channel to a different channel, which enables the implementation of CM-controlled load-balancing algorithms.


         The disclosed method provides advantages, including:

•         Improved functionality due t...