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Here's a look at some of the products you will be able to see at the show:

The ability for a MAC to provide access to the physical transportmedium within tightly bounded limits of time (isochronous) is whatdetermines whether a particular MAC is capable of guaranteeing the QoSrequired for a whole-home entertainment network.

A MAC that can't guarantee access to the PHY layer transport mediawithin tightly bounded time limits is considered to be a best effort”type of network.

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CSMA, TDMA The predominant MAC architectures used in home networking technologiestoday largely support two channel access schemes known as carrier sensemultiple access (CSMA) and time division multiple access (TDMA).

CSMA enables the Ethernet and Wi-Fi technologies found in our homesand offices today. These were designed for network functions such asbulk file transfer, e-mail, simple Internet access and printer sharing.

Because of their legacy use in our homes and offices, there areattempts to modify CSMA networks to support multimedia networking byadding prioritization” (parameterization).

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These result in better performance for multimedia over suchnetworks, but do not address two fundamental issues and thus fall shortof guaranteed” QoS.

The first fundamental issue is the contention-based access to thephysical transport media. Because the CSMA scheme is not scheduled, QoS(delivery time, jitter) is not guaranteed” due to delays associatedwith collisions or collision-avoidance protocols. The second issue isthe connectionless, prioritized transmission of data, which relies onintermediate nodes to have enough resource and intelligence to get thedata delivered to the endpoint.

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Alternately, TDMA provides a suitable foundation for multimedianetworks. TDMA guarantees QoS within tightly bounded limits of time andsupports isochronous data streams such as those required bymultichannel audio and HDTV. TDMA is fundamental to the IEEE 802.15.3bMAC, which is used by CWave.

The QoS requirements of entertainment networks differ from networksfor e-mail, file sharing and printing. In an entertainment network, ifthe data does not arrive on time, every time, the TV screen goes blank,and displays errors such as video artifacts or dropped audio. Thedelivery of data within tightly bounded limits of time is referred toas deterministic” or isochronous.”

The MAC sub-layer interfaces to the logical link control (LLC)sub-layer at the very top of L2. The output of the LLC into the L3network layer is the common convergence point where the network stacksfor wireless, Ethernet, coax and power line become common.

The MAC provides logical control of how and when the network node isgiven physical access to the actual network transport medium. This iswhat makes it possible for several network nodes to be connected to thesame physical medium and to cooperatively share access to it.

The ability for a MAC to provide access to the physical transportmedium within tightly bounded limits of time (isochronous) is whatdetermines whether a particular MAC is capable of guaranteeing the QoSrequired for a whole-home entertainment network.

A MAC that can't guarantee access to the PHY layer transport mediawithin tightly bounded time limits is considered to be a best effort”type of network.

CSMA, TDMA The predominant MAC architectures used in home networking technologiestoday largely support two channel access schemes known as carrier sensemultiple access (CSMA) and time division multiple access (TDMA).