Cable Forum - View Single Post - Forums response to my recent UK VM Tech Advice

Ignitionnet · 04-02-2010, 11:21

I mean the DOCSIS 3 network, who / what is on it isn't really too bothersome I was referring to how the network was built.

Load balancing, spreading modems across all the platforms to try and even up the load. It's a great idea until one notes that those modems that previously were on 3 or 4 upstreams on the DOCSIS 1.0 network are now sitting on 1, and are 50Mbit and a higher concentration of 20Mbit users.

From the view of a single cable modem the networks look like this, I emphasise this is the view of a single cable modem and the channels it can acquire, not what it looks like on the card at the headend, that is irrelevant:

DOCSIS 1 network, bog standard build - 1 downstream @ 38Mbit, 4 upstreams @ ~4.5 or ~9Mbit or a combination of the two.
DOCSIS 3 network - 4 downstreams @ 50Mbit each, 1 upstream @ 9Mbit.

Just to add to the delight each DOCSIS 1 area of 1 downstream and 4 upstreams may actually be joined with another area that it was previously resegmented from before being pushed onto the single upstream on the DOCSIS 3 network, so you may actually be in a position where there were previously some modems split across eight upstreams being funnelled onto one

Do we see a problem here using the standard capacity planning? *Nods* We do. Oh yes.

I posted about it as I mentioned in 2008 both here and to technical support in the newsgroups expressing my concern about this architecture. Seems I was a year ahead of the curve. They threw the DOCSIS 3 network in as quickly and cheaply as possible, it's in the past weeks started to really bite them in the arse.

EDIT: One would have hoped this would provide extra momentum to JFDI with regards to the upstream upgrades needed for the uplifts to upstream bandwidth, evidently not as those upgrades that are being done consist of reducing the modems per upstream port, which is fine but can take quite a while, rather than increasing the bandwidth on the ports which would be potentially much faster and will be required as part of the upstream upgrade anyway. There seems no interest in doing anything bar business as usual in that regard, resegmentation, or more accurately in some cases re-resegmentation given they undid previous segmentation in some cases, where capacity is a problem rather than long overdue DOCSIS upgrade.

04-02-2010, 11:21	#6
Ignitionnet Inactive Join Date: Jun 2008 Location: Leeds, West Yorkshire Age: 47 Posts: 13,995	Re: Forums response to my recent UK VM Tech Advice I mean the DOCSIS 3 network, who / what is on it isn't really too bothersome I was referring to how the network was built. Load balancing, spreading modems across all the platforms to try and even up the load. It's a great idea until one notes that those modems that previously were on 3 or 4 upstreams on the DOCSIS 1.0 network are now sitting on 1, and are 50Mbit and a higher concentration of 20Mbit users. From the view of a single cable modem the networks look like this, I emphasise this is the view of a single cable modem and the channels it can acquire, not what it looks like on the card at the headend, that is irrelevant: DOCSIS 1 network, bog standard build - 1 downstream @ 38Mbit, 4 upstreams @ ~4.5 or ~9Mbit or a combination of the two. DOCSIS 3 network - 4 downstreams @ 50Mbit each, 1 upstream @ 9Mbit. Just to add to the delight each DOCSIS 1 area of 1 downstream and 4 upstreams may actually be joined with another area that it was previously resegmented from before being pushed onto the single upstream on the DOCSIS 3 network, so you may actually be in a position where there were previously some modems split across eight upstreams being funnelled onto one Do we see a problem here using the standard capacity planning? Nods We do. Oh yes. I posted about it as I mentioned in 2008 both here and to technical support in the newsgroups expressing my concern about this architecture. Seems I was a year ahead of the curve. They threw the DOCSIS 3 network in as quickly and cheaply as possible, it's in the past weeks started to really bite them in the arse. EDIT: One would have hoped this would provide extra momentum to JFDI with regards to the upstream upgrades needed for the uplifts to upstream bandwidth, evidently not as those upgrades that are being done consist of reducing the modems per upstream port, which is fine but can take quite a while, rather than increasing the bandwidth on the ports which would be potentially much faster and will be required as part of the upstream upgrade anyway. There seems no interest in doing anything bar business as usual in that regard, resegmentation, or more accurately in some cases re-resegmentation given they undid previous segmentation in some cases, where capacity is a problem rather than long overdue DOCSIS upgrade.