The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 15, 2004
Filed:
May. 24, 1999
Mark O. Vogel, Hampshire, IL (US);
Ali Akgun, Evanston, IL (US);
3Com Corporation, Marlborough, MA (US);
Abstract
A head-end in a data-over-cable system transmits a multicast message in a downstream channel to all the cable modems in a particular MAC layer. The message includes an address field that contains an upstream channel multicast MAC address that identifies a particular channel, and is used to send a multicast message for which only cable modems transmitting in the upstream direction in that channel are to respond. When the message is received by the cable modems, the cable modems compare the upstream channel multicast MAC address with addresses stored in a memory. If a match is found, indicating that the cable modem happens to transmit in the upstream direction in the particular channel, it processes the message. If no match is found, the message is discarded. The upstream channel multicast MAC address helps noise avoidance or redundancy problems associated with a particular channel to be quickly remedied, and avoids the head-end from having to send out a large number of unicast messages in order to communicate with all the modems sharing a given upstream channel.