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percosan

join:2002-03-13
San Francisco, CA

The Godfather does not understand D3

There is no 35 Mb/s upstream limitation in the DOCSIS specification. In fact, current certified devices support 4 bonded channels yielding ~100 Mb/s and future devices could add more upstream as requested by MSOs.

Same goes for downstream ... the spec is not the issue. It is the product that Cable sells.

Stan

fifty nine

join:2002-09-25
Sussex, NJ
kudos:2

Re: The Godfather does not understand D3

I thought that the current return path was limited due to noise issues.

NetAdmin1
CCNA

join:2008-05-22

1 recommendation

said by percosan:

There is no 35 Mb/s upstream limitation in the DOCSIS specification.
Technically correct. The DOCSIS 3 spec has a ~30mbps upstream limitation per channel. The change is that DOCSIS 3 supports channel bonding. If a provider only uses one upstream channel, by spec they are limited to ~30mbps.
--
"This is a bus. You know how big a bus is?"

fifty nine

join:2002-09-25
Sussex, NJ
kudos:2

Re: The Godfather does not understand D3

Is anyone currently using channel bonding for upstream? Someone posted here yesterday that no one has ever got it working.

Phil
Rojo Sol
Premium
join:2001-06-11
Downers Grove, IL
kudos:2

Re: The Godfather does not understand D3

I believe you're correct in that that technology hasn't been fully developed yet.

jadebangle
Premium
join:2007-05-22
00000
kudos:1
said by NetAdmin1:

said by percosan:

There is no 35 Mb/s upstream limitation in the DOCSIS specification.
Technically correct. The DOCSIS 3 spec has a ~30mbps upstream limitation per channel. The change is that DOCSIS 3 supports channel bonding. If a provider only uses one upstream channel, by spec they are limited to ~30mbps.
Are you saying that only 1 channel is used per subscriber? I thought they use 4 normally and 8 with channel bonding. To give us speed of 152mbit/108mbit
The latter will never be used, just some theory on a spec sheet

Its 27mbit per channel, 30mbit is theoretically speaking much like a harddrive that is advertised as 100gb but is really 93gb.

voipguy

join:2006-05-31
Forest Hills, NY

Re: The Godfather does not understand D3

Upstream channel bonding is not yet supported/qualified by the major CMTS vendors and Cablelabs. That will come with a "Silver" or "Full" DOCSIS 3.0 certification. Try as he might, the LightReading host could not get vendors or Cablelabs to speculate on the date that will come. Once it does, then you'll see cable operators offering higher upstream speeds.

The conference also covered other advanced CATV architectures that can bring speeds well beyond even what DOCSIS 3.0 can offer.

fifty nine

join:2002-09-25
Sussex, NJ
kudos:2

Re: The Godfather does not understand D3

So in other words, it has the potential to be vaporware.

RadioDoc
Premium,ExMod 2000-03
join:2000-05-11
La Grange, IL
kudos:2

Re: The Godfather does not understand D3

Potential? Right now it is vaporware. PR-ware, if you would, in a desperate attempt to counter FiOS-type competition's leg up in the press release war. Nobody will see anything approaching 100 megabits up from DOCSIS cable anytime soon.

fifty nine

join:2002-09-25
Sussex, NJ
kudos:2

Re: The Godfather does not understand D3

I think the major stumbling block is that 5-42MHz return path. That was a carryover from what... when John Walson was running tube amps in people's basements?
percosan

join:2002-03-13
San Francisco, CA
This is incorrect.

DOCSIS 3 is not vaporware ... what is lacking is a strong go to market plan in the US. Basically, no direct threat means no "early deployment". D3 is being commercially deployed in Japan (160 Mb/s), Netherlands (> 100), Portugal (100 Mb/s), Canada (100 Mb/s) and in other countries at lower rates such as UK (50 Mb/s), US (50 Mb/s) ...

Just because it is not being offered today in the US at achievable rates or reasonable price does not mean it is vaporware.

-p

said by RadioDoc:

Potential? Right now it is vaporware. PR-ware, if you would, in a desperate attempt to counter FiOS-type competition's leg up in the press release war. Nobody will see anything approaching 100 megabits up from DOCSIS cable anytime soon.

fifty nine

join:2002-09-25
Sussex, NJ
kudos:2

1 edit

Re: The Godfather does not understand D3

So in those countries they have both the upstream and downstream at those speeds?

Remember we are not talking about DOCSIS3 itself, but the upstream channel bonding.

I have DOCSIS3 at home by the way so I know it's not vaporware.
percosan

join:2002-03-13
San Francisco, CA

Re: The Godfather does not understand D3

Current upstream speeds are lower (I will look them up).

The main issue is that DOCSIS 3.0 is not the limiting factor. I believe previous posters have referenced the lack of CMTS availability, but again, this is not related to DOCSIS and more to MSO demand.

-p

NetAdmin1
CCNA

join:2008-05-22
said by jadebangle:

Are you saying that only 1 channel is used per subscriber?
No. Providers have the option under DOCSIS 3 to use a single 6Mhz upstream channel or either 4 or 8 6Mhz upstream channels bonded together.

In any of those configurations, that upstream is shared between all subscribers on that CMTS interface.
--
"This is a bus. You know how big a bus is?"

fifty nine

join:2002-09-25
Sussex, NJ
kudos:2

Re: The Godfather does not understand D3

said by NetAdmin1:

said by jadebangle:

Are you saying that only 1 channel is used per subscriber?
No. Providers have the option under DOCSIS 3 to use a single 6Mhz upstream channel or either 4 or 8 6Mhz upstream channels bonded together.

In any of those configurations, that upstream is shared between all subscribers on that CMTS interface.
I don't know of any provider using more than 1 upstream channel. My DPC2505 only uses 1 upstream channel.

NetAdmin1
CCNA

join:2008-05-22

Re: The Godfather does not understand D3

said by fifty nine:

I don't know of any provider using more than 1 upstream channel. My DPC2505 only uses 1 upstream channel.
That's because there is very little hardware that supports upstream bonding. Downstream has been the priority for most providers since that is the thing that most consumers notice.
--
"This is a bus. You know how big a bus is?"
percosan

join:2002-03-13
San Francisco, CA
It is important to point out that the DPC2505 is not a DOCSIS 3.0 modem. It is a proprietary modem that "is designed to meet DOCSIS 2.0 specifications" (a quote from their data sheet).

Anyway, a real DOCSIS 3.0 modem will support at least 4 upstreams.

-p
Lazlow

join:2006-08-07
Saint Louis, MO

Re: The Godfather does not understand D3

percosan

Can you post a link to a modem that is certified for upstream channel bonding? I cannot find one.

AnonCow2

@comcast.net

Re: The Godfather does not understand D3

I was under the impression that Cable Modems
were not certified in the same manner as CMTSs
with respect to upstream/downstream channel
bonding capabilities (i.e. Bronze, Silver, Full).
AFAIK, a DOCSIS 3.0 certified Cable Modem carries
the equivalent of a "Full" certification and
supports the bonding of at least 4 downstream
and 4 upstream channels. The main impediment
to upstream bonding is not the Cable Modems
but the lack of Silver/Full certified CMTSs.
percosan

join:2002-03-13
San Francisco, CA

Re: The Godfather does not understand D3

This is mostly true. Cable Modems and CMTSs were certified/qualified in the same manner as all previous waves. However, for DOCSIS 3.0, Cable Modems were required to be feature complete to achieve certification. CMTSs were given an "on ramp" to accelerate overall certification progress.

-p
percosan

join:2002-03-13
San Francisco, CA
Sure, here you go ...

»www.scientificatlanta.com/custom ··· 8362.pdf

-p

said by Lazlow:

percosan

Can you post a link to a modem that is certified for upstream channel bonding? I cannot find one.
Lazlow

join:2006-08-07
Saint Louis, MO

Re: The Godfather does not understand D3

percosan

The DPC2505 (according to your PDF) is "DOCSIS 3.0 compatible; operates in DOCSIS 3.0 networks" but is" Designed to meet DOCSIS 2.0 specifications". I did not see anywhere in there that said that it was D3 certified. I also did not see anywhere it said anything about UPSTREAM bonding.
percosan

join:2002-03-13
San Francisco, CA

Re: The Godfather does not understand D3

This was my point. The DPC2505 IS NOT DOCSIS 3.0. It is proprietary and supports a small subset of D3 features.

-s

said by Lazlow:

percosan

The DPC2505 (according to your PDF) is "DOCSIS 3.0 compatible; operates in DOCSIS 3.0 networks" but is" Designed to meet DOCSIS 2.0 specifications". I did not see anywhere in there that said that it was D3 certified. I also did not see anywhere it said anything about UPSTREAM bonding.
Lazlow

join:2006-08-07
Saint Louis, MO

Re: The Godfather does not understand D3

Which is EXACTLY my point. Until someone produces a system (working in the field), upstream D3 is just vaporware.

Ignite
Premium,VIP
join:2004-03-18
UK
Reviews:
·PlusNet

Re: The Godfather does not understand D3

Ambit, Arris, Cisco, Motorola and SMC all have modems which support upstream bonding of 4 channels.

The only CMTSes which support upstream bonding at this time are the Casa C2200 and C3200, however these are working as proven through testing.

I am not aware of any commercial deployments of the technology, however if there are none this is for commercial reasons not technological ones. The silicon is in modems for up to 8 downstreams and 4 upstreams and the Casa CMTS will bond 16 streams in both directions.

NetAdmin1
CCNA

join:2008-05-22
said by jadebangle:

Its 27mbit per channel, 30mbit is theoretically speaking much like a harddrive that is advertised as 100gb but is really 93gb.
No, it is 30.72Mbps per channel. The 27Mbps numbers is after framing, error correction and other factors are taken into account. However, the capacity of a single DOCSIS channel is 30.72Mbps.
--
"This is a bus. You know how big a bus is?"

AnonCow2

@WV.CC.CMU.EDU
Exactly. Time to depose this so-called godfather. The DOCSIS 3.0 spec imposes no limitation on the number of upstream/downstream bonded channels. Cookish of Motorola described the very straightforward (if somewhat cap-ex intensive) approach to boost upstream speeds. Also, the silicon vendors will continue to increase their support for the numbers of bonded channels and prices for D3 modems will continue to decline.