Methods and apparatus for efficient IP multicasting in a content-based network
First Claim
1. In a broadcast-switched architecture (BSA) cable network having at least one cable modem termination system (CMTS) and a plurality of cable modems in signal communication therewith, a method of providing a plurality of content channels to network subscribers via respective ones of said modems, the method comprising:
- transmitting first packetized content over a first channel to at least a first of said modems;
transmitting second packetized content over a second channel to at least a second of said modems; and
selectively switching said second modem to said first channel so that said first and second modems receive said first and second packetized content in a substantially multicast fashion;
from the same physical channel wherein said first and second channels comprise a portion of the plurality of content channels, at least a portion of said plurality of channels being switched for delivery to CPE located proximate to respective ones of said plurality of cable modems.
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Abstract
Methods and apparatus for assigning physical channels in a content-based network. In an exemplary embodiment, the network comprises a cable television network having a plurality of cable modems, and the physical channels are assigned to the cable modems based at least in part on any multicast transmissions that may exist on the system. When two cable modems are receiving the same multicast transmission, the invention causes tuning of one or more of the cable modems to the same physical channel in order to limit the total number multicast transmissions on the network. Multicast transmissions typically comprise video or audio information, but other types of information may also be multicast according to the invention. In another embodiment, a multicast transmission list (containing a list of multicast transmissions and the corresponding physical channels) is sent to the set of cable modems. This list is used by the modems (or associated CPE) to manage channel allocation and tuning.
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Citations
33 Claims
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1. In a broadcast-switched architecture (BSA) cable network having at least one cable modem termination system (CMTS) and a plurality of cable modems in signal communication therewith, a method of providing a plurality of content channels to network subscribers via respective ones of said modems, the method comprising:
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transmitting first packetized content over a first channel to at least a first of said modems;
transmitting second packetized content over a second channel to at least a second of said modems; and
selectively switching said second modem to said first channel so that said first and second modems receive said first and second packetized content in a substantially multicast fashion;
from the same physical channelwherein said first and second channels comprise a portion of the plurality of content channels, at least a portion of said plurality of channels being switched for delivery to CPE located proximate to respective ones of said plurality of cable modems. - View Dependent Claims (2, 3, 4, 31)
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5. A system for performing multicasting over a cable network, comprising:
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a plurality of cable modems;
a cable modem termination system in data communication with said plurality of cable modems; and
a controller adapted to track the state of multicast transmissions to said plurality of cable modems, detect that a cable modem assigned to a first physical channel selects a combination of multicast transmissions available on a second physical channel, and cause said cable modem to switch from a first channel to said second channel. - View Dependent Claims (6, 7, 8, 9, 10)
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11. In a cable television network that comprises a plurality of cable modems, a modem termination system and a plurality of physical channels allowing communication between said plurality of cable modems and said cable modem termination system, a method of operating comprising:
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monitoring a first cable modem receiving a first multicast transmission on a first physical channel;
detecting a second cable modem assigned to a second physical channel receiving said first multicast transmission; and
causing said second cable modem to switch to said first physical channel. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A method for operating a cable modem in a cable network, the method comprising:
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receiving IP packets on a first physical channel;
generating a request to receive a multicast transmission;
receiving information used as the basis of switching said cable modem to a second physical channel; and
switching said cable modem to said second physical channel. - View Dependent Claims (19, 20, 21, 22)
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23. Cable modem apparatus adapted to process network traffic comprising:
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a digital signal processing unit capable of processing data from a first physical channel; and
a control unit configured to generate a request to receive a multicast transmission, to receive a message to switch from a first physical channel to a second physical channel in response to said request, and to configure said digital signal processing unit to process said second physical channel. - View Dependent Claims (24, 25, 26)
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27. Apparatus adapted to control multicasting within a cable network, said cable network including a plurality of cable modems, comprising:
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a cable modem termination system communicating with said plurality of cable modems; and
a controller adapted to track the state of multicast transmissions to said cable modems, said controller being able to detect that a cable modem assigned to a first physical channel of said network selects a multicast transmission available on a second physical channel, and instruct said cable modem to switch from said first channel to said second channel. - View Dependent Claims (28)
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29. In a cable network comprising a hub, a plurality of cable modems, and a set of physical channels providing communication between said hub to said cable modems, a method of operating said cable network to efficiently deliver multicast packetized transmissions, comprising:
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transmitting a multicast transmission list message from said hub to at least a portion of said cable modems, said message listing a set of multicast transmissions and at least one corresponding physical channel on which each multicast transmission is being transmitted;
receiving a request to receive a first multicast transmission from said set of multicast transmissions; and
configuring at least one of said cable modems to process a physical channel associated with said first multicast transmission based at least in part on said multicast transmission list message. - View Dependent Claims (30)
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32. In a switched content-based network having a node and a plurality of subscriber devices adapted to receive packet service from said node, a method of conserving bandwidth during delivery of said packet service, comprising:
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selectively switching one or more of a plurality of downstream packet channels only when they are required by one or more users being serviced by said node; and
selectively switching one or more of said subscriber devices to a packet service channels of said node so as to deliver a common multicast transmission to two or more of said devices using said packet service channel, said selective switching of said one or more devices obviating the need to replicate said multicast transmission on a second packet service channel.
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33. Consumer premises equipment (CPE) adapted to selectively retune itself to at least one of a plurality of physical channels based at least in part on (i) a downstream communication received by said CPE that maps at least one multicast transmission to at least one physical channel, and (ii) a communication received from a client device in communication with said CPE requesting delivery of said at least one multicast transmission.
Specification