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Ignitionnet · 02-10-2011, 13:56

64QAM = 6 bits per symbol, 16QAM = 4, 50% increase, exponential.

The real world sadly isn't as accommodating as just adding channels. RF noise and network restrictions can restrict the amount of usable bandwidth, upstream bonding is still not a finished article within the software on the Cisco and Motorola CMTS and carries its own restrictions, along with how the various CPE interoperate.

Statistical contention through wider channels is the ideal but gives its own issues, node splits are good for bandwidth and good for network condition due to noise funneling effects, higher order modulations require smaller nodes.

Unsure what you refer to by letting the upstream suffer, given that the uplifts were released on a single upstream and a second and depending on the area third channel have been put in place, however VM know they are behind the curve in some areas.

It's not ideal, work on bonding is underway, but we can debate ideals all we want, the real world is a bitch and constantly interferes, depending on area channels can house a lot of 3Mb, 5Mb, 10Mb upstream customers even on 18Mb without causing problems.

It's never as simple as on paper, what you feel is the minimal really isn't, very few MSOs have upstream bonding widely deployed, for example these guys and these guys don't and UPC sell 120Mb/10Mb on 4 x 256QAM down, 1 x 16QAM up, Comhem 200Mb/10Mb on 5 or 6 x 256QAM down and 1 x 16 or 64QAM up.

02-10-2011, 13:56	#48
Ignitionnet Inactive Join Date: Jun 2008 Location: Leeds, West Yorkshire Age: 47 Posts: 13,995	Re: Should i worry? 64QAM = 6 bits per symbol, 16QAM = 4, 50% increase, exponential. The real world sadly isn't as accommodating as just adding channels. RF noise and network restrictions can restrict the amount of usable bandwidth, upstream bonding is still not a finished article within the software on the Cisco and Motorola CMTS and carries its own restrictions, along with how the various CPE interoperate. Statistical contention through wider channels is the ideal but gives its own issues, node splits are good for bandwidth and good for network condition due to noise funneling effects, higher order modulations require smaller nodes. Unsure what you refer to by letting the upstream suffer, given that the uplifts were released on a single upstream and a second and depending on the area third channel have been put in place, however VM know they are behind the curve in some areas. It's not ideal, work on bonding is underway, but we can debate ideals all we want, the real world is a bitch and constantly interferes, depending on area channels can house a lot of 3Mb, 5Mb, 10Mb upstream customers even on 18Mb without causing problems. It's never as simple as on paper, what you feel is the minimal really isn't, very few MSOs have upstream bonding widely deployed, for example these guys and these guys don't and UPC sell 120Mb/10Mb on 4 x 256QAM down, 1 x 16QAM up, Comhem 200Mb/10Mb on 5 or 6 x 256QAM down and 1 x 16 or 64QAM up.