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UPC netherlands starts docisis 3.0

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  • 01-09-2008 11:05pm
    #1
    everdead.ie
    Registered Users Posts: 9,153 ✭✭✭


    ok so UPC Netherlands is starting the roll out of docsis 3.0 next month i was wondering if any upc employees are looking at this could you tell me how many channels are in the new hfc your laying because pressuming docsis 3.0 is rolled out here the maximum download speeds will be determined by the amount of channels available. As has been mentioned in previous threads they have trialed 100mb/s in the netherlands and 120 in their research facility in cork.


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    #2
    bk
    Moderators, Motoring & Transport Moderators, Technology & Internet Moderators Posts: 22,713 Mod ✭✭✭✭bk


    I don't work for UPC.

    A modern HFC network should typically give you over 500MHz of bandwidth, which is typically divided into 8MHz channels, you can do the maths yourself.

    However the reality is that most of these channels is taken up by TV channels, each 8MHz channel equals one analogue TV channel (obviously) and roughly 10 digital channels.

    DOCSIS 3 uses a minimum of 4 channels bonded together to give you 222.48Mb/s, of course this is shared amongst multiple users.


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    #3
    watty
    Registered Users Posts: 32,417 ✭✭✭✭watty


    Yes, you need much shorter cable segments than was historical in Ireland or else the capacity does not exist. You need Fibre to kerb/ HFC systems. Analogue TV would bite the dust. There is much less upstream capacity, only 60MHz per cable. The downstream can be over 750MHz on DOCSIS 2.0 and about 890MHz on DOCSIS 3.0

    It's longer coax that can't support DOCSIS 3.0 anyway that is limited to 350Mhz to 500MHz downstream and maybe 30MHz only upstream.

    The 4 channels could be dedicated in theory... But who wants to pay for 1:1 contention 200Mbps downstream with only 6Mbps upstream?

    Even without DOCSIS3, analogue on cable is doomed as demand increases for Broadband and HD.

    There is another trick to get "extra" bandwidth if the number of users on cable segment is less than number of channels. You make 1/2 of the channels dynamic. When you change channel, if the channel is not on cable and there are unwatched channels, a channel is switched. Obviously the cable boxes must use the broadband every channel change. Like DOCSIS 3.0 it's only feasible on short cable runs of HFC. On a 250 channel system with only 50 to 100 connections (don't forget users could have multiroom) you thus can have 1000 channels, inc HD, with 120 fixed channels and 120 switched video channels. Since about 98% of viewing can be accomodated on less than 60 channels, you make those popular ones the fixed ones. Only the people on HD and/or higher packs need the broadband hybrid boxes. Which also support real time and push (hidden pre loaded) VOD.

    I don't work for UPC either.


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