100M : VMNG300 92Mbit limit

[horseman]

Originally Posted by qasdfdsaq

…. DOCSIS 2 modems would all have to be on channel 1.

Well it's not quite that simple but you get the idea. Still nowhere near as bad as a bunch of legacy modems.

Indeed it's not as simple because legacy single channel CM's would only be limited to primary channels as and when VM decided to disable MAP on the secondary channels in order to reduce DOCSIS overheads (to increase data payload), otherwise legacy CM's could potentially load balance across any d/s channel configured within their load balance group.

[Chrysalis]

I was able to change channels on my docsis 1 modem. Its just the usual channel hopping process, turn modem off for long enough then turn it back on again and hope it uses a new channel, so my experience was not that it always used a primary channel.

There is no doubt tho that the docsis3 experience on a docsis1 modem is severely hindered, qas probably remembers when I signed up to 30mbit on the docsis1 modem on the 20mbit service on docsis3 network my speeds were at the time chaotic, I upgraded and got the superhub and then on a docsis3 device they stabilised and that was with a 50% higher speed package also.

[horseman]

Originally Posted by Chrysalis

….There is no doubt tho that the docsis3 experience on a docsis1 modem is severely hindered, qas probably remembers when I signed up to 30mbit on the docsis1 modem on the 20mbit service on docsis3 network my speeds were at the time chaotic, I upgraded and got the superhub and then on a docsis3 device they stabilised and that was with a 50% higher speed package also.

Again there is indeed every doubt you can validly state(or infer) that experience is typical unless you present some degree of objective comparison with some analysis of the linecard types, number of cm's deployed per LC/port and types involved along with load balance groups, channel/frequency plans used.

For example I was quite happily provisioned on an Ambit256 via a D3 compliant CMTS for 18months without a degraded service until migrating to a SHub(with same IP) a couple of months ago. Similarly my son was on Ambit250 legacy (with 20XL tier, and still is!) before migrating to SuperHub over a year ago. However only when both d/s & u/s channels increased could a significant improvement be observed!

That said however using DOCSIS "mixed mode" is going to be finitely less efficient anyway without a doubt but until VM eventually migrate the remainder of their 4million+ BB subscribers it's going to be around for a long time yet. If VM did reduce the number of channels with MAP data and/or had not allocated correct load balance group configurations then your scenario may well have occurred to the detriment of the DOCSIS legacy CM, and perhaps even more so than the D3 unit.

Like most things here it's another pointless argument without supportive evidential data to compare objectively and thus only represents a couple of observations based on a limited statistical sample base.

[Chrysalis]

horseman my area has had high DS utilisation for years, so when that is combined with a modem that relies on just 1 DS channel its clear it will have issues. My guess if your area had lower DS utilisation than mine.

eg. there is currently a high DS utilisation fault open on my area now (again).

the scenario I had may have been.

DS channels - utilisations
1 - 80%
2 - 90%
3 - 70%
4 - 75%

with all 4 bonded 30mbit throughput available so no visible congestion downloading, but on a d1 modem no single channel had 20mbit throughput available hence congestion.