Quote:
Originally Posted by Sephiroth
At least Igni is consistent by saying SNR is a stumbling block. (See here).
But as I see it, if 1024QAM requires 38-41 dB SNR and if most of the SH's are reporting this downstream SNR value, it may be worth trialling this because modems will also acquire at 256QAM. |
No they won't, any modems that can't handle 1024QAM will error and/or fall offline, there is no spectrum management and no ability to downrate downstreams to accommodate modems with marginal SNRs.
VM could work around this by periodically probing modems for their downstream SNR however where do you draw the line as far as the amount of customers you allow to have a marginal or non-existent service and think of the OSS expense?
Compare this to investing in higher density line cards when you are going to be swapping some line cards out due to upstream bonding requirements anyway - no brainer.
The acid test for this really is a simple one - how many operators are running 1024QAM, and how many have supplied additional capacity simply by using 8 x 256QAM downstream compatible CPE and filling the downstream channels?
Is there a pressing need for more than 400Mbps to a single service group right now? When there is a need for more than this 16 downstream silicon both on line cards and modems is waiting.