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patcat88
join:2002-04-05
Jamaica, NY
kudos:1 | coax Ethernet from the node?????? If your running ethernet over coax for the last mile, why dont they deploy ethernet over coax from a fiber node for the last mile, much higher speeds, less overhead, less D2A, A2A, A2C conversions. The DOCSIS 3 to Coax Ethernet convertor isnt going to be a cheap piece of equipment (its active electronics), and it eats line power, why dont they just do Coax Ethernet to the home stright from the nice fat fiber node? | |
DMS1
join:2005-04-06
Carrollton, TX | said by patcat88:If your running ethernet over coax for the last mile, why dont they deploy ethernet over coax from a fiber node for the last mile, much higher speeds, less overhead, less D2A, A2A, A2C conversions. The DOCSIS 3 to Coax Ethernet convertor isnt going to be a cheap piece of equipment (its active electronics), and it eats line power, why dont they just do Coax Ethernet to the home stright from the nice fat fiber node? Presumably because that would involve a cabling infrastructure upgrade too. A typical HFC network consists of a node that drives a hundred or more drops via a series of amplifiers and multi-port taps. I guess that what NTL are planning to do is place a multi-user DOCSIS 3 modem in each tap (which from what I remember have many more ports than the typical tap used in the US), meaning that each user then has a dedicated coax link from the modem to their house. With your plan, multiple Ethernet-over-coax links would need to be carried from the node to the taps, and this may be beyond the capabilities of the existing coax. | |
patcat88
join:2002-04-05
Jamaica, NY
kudos:1 | said by DMS1:Presumably because that would involve a cabling infrastructure upgrade too. A typical HFC network consists of a node that drives a hundred or more drops via a series of amplifiers and multi-port taps. I guess that what NTL are planning to do is place a multi-user DOCSIS 3 modem in each tap (which from what I remember have many more ports than the typical tap used in the US), meaning that each user then has a dedicated coax link from the modem to their house. With your plan, multiple Ethernet-over-coax links would need to be carried from the node to the taps, and this may be beyond the capabilities of the existing coax. Isnt the speed increase nullified by sharing a individual modem? | |
DMS1
join:2005-04-06
Carrollton, TX | said by patcat88:Isnt the speed increase nullified by sharing a individual modem? I suspect that the "device" is actually a multiple-modem unit. In other words, it offers the same functionality as multiple individual modems but in one physical device, allowing the sharing of some circuitry such as the node-side interface, power supply, control function etc. This sharing would ensure that an N-port modem was considerably cheaper than 'N' discrete modems. | |
 IgnitePremium,VIP
join:2004-03-18
UK | reply to patcat88
said by patcat88:If your running ethernet over coax for the last mile, why dont they deploy ethernet over coax from a fiber node for the last mile, much higher speeds, less overhead, less D2A, A2A, A2C conversions. The DOCSIS 3 to Coax Ethernet convertor isnt going to be a cheap piece of equipment (its active electronics), and it eats line power, why dont they just do Coax Ethernet to the home stright from the nice fat fiber node? Range and the requirement to add additional equipment to every cabinet on the path from node to customer doing it that way.
Check the Narad Networks products, you'll note that to get the signal through a standard CATV amp it needs to be split off before the CATV amp then recombined with the output of the CATV amp it as it has to work at different frequencies which are outside the range of the CATV amps, which usually tend to max on most plants at 880MHz or less.
Unlikely for there to be room there for the ethernet signal, but enough room for 4 6/8MHz wide QAM carriers, yep, sure. | | |
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