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jhuk
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Comcast tests tech that enables gigabit upload speeds over cable

 

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Just a few years ago Comcast started rolling out 1Gbps cable service and now it’s widely available in many areas across the country, but it still can’t match fiber for upload speed. Many fiber services offer gigabit speeds for customers on uploads and downloads, while the Xfinity package is limited to 35Mbps upload, at a time when people are creating more content and producing more video streams from home than ever before.

This week however, Comcast ran a test that enabled 1.25Gbps speeds up and down on their live network at a home in Jacksonville. There’s no word on when that kind of service will be available to more consumers, but they were able to pull it off with their Distributed Access Architecture (DAA) that combines “digital fiber optics, “Remote PHY” digital nodes, and a cloud-based, virtualized cable modem termination system platform (vCMTS).” This is a milestone on the way to its “10G platform,” that claims it will enable speeds of 10Gbps and higher."

Comcast tests tech that enables gigabit upload speeds over cable | Engadget

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Andrew-G
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Re: Comcast tests tech that enables gigabit upload speeds over cable

That sounds like full duplex DOCSIS 3.1, which will not be appearing with VM any time soon.  I must say the press release wrapped it up in complete bull**** bingo, with utter drivel like "a cloud-based, virtualized cable modem termination system platform".  I'm surprised the term "AI" didn't get thrown in by their breathless PR team.

For VM, rolling out D3.1FD would require a new hub, probably a new CMTS, and new network architecture to allow VM's backhaul to cope with the faster speeds.  That's going to be at least as complex and costly as the ongoing D3.1 rollout.  Even if it happens, VM wouldn't be looking at doing anything for probably five years after the D3.1 roll out is complete in order to get that working properly and depreciate the hubs and network investments, so I'd suggest earliest start for a D3.1FD programme would be 2026, and earliest network completion would be around 2028-2030.  Even then, where's the commercial case?  I can't see enough customers would be willing to pay around £7 a month extra to cover the costs, and by then most people will have an Openreach FTTP option or other gigabit capable offer, so VM won't have the luxury of inflating every customer's bill simply because they are the only high speed game in town.

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cje85
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Re: Comcast tests tech that enables gigabit upload speeds over cable


@Andrew-G wrote:

That sounds like full duplex DOCSIS 3.1, which will not be appearing with VM any time soon.  I must say the press release wrapped it up in complete bull**** bingo, with utter drivel like "a cloud-based, virtualized cable modem termination system platform".  I'm surprised the term "AI" didn't get thrown in by their breathless PR team.


Cloud based CMTS is a very real thing.

https://blogs.cisco.com/sp/cloud-native-cmts-next-gen-virtualization-for-cable-access

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Andrew-G
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Re: Comcast tests tech that enables gigabit upload speeds over cable

@cje85 Cloud based CMTS is a very real thing.

According to the people selling it yes.  When you consider that

  • Cloud based computing is simply remote server processing, usually outsourced, and...
  • a CMTS is in principle a big, hairy modem, aggregating and converting customer's analogue closed circuit RF signals to a digital optical output to VM's  backhaul, and the other way converting optical signals back to RF signals that , and hubs, TV's and set top boxes can use... 

...there's no way I can see of taking the signal processing required to convert analogue RF to digital optical and shifting that processing to somebody else's bit barn unless you had an analogue backhaul between each physical CMTS and the logical & virtual cloud CMTS.  Which makes zero sense, and would cause calamitous capacity constraints along with horrendous latency issues.

If you still have the CMTS executing modulation/demodulation and local traffic management, what exactly is cloud based about that?

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gitty
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Re: Comcast tests tech that enables gigabit upload speeds over cable

There is no RF involved at the CMTS when going virtual/cloud. Remote PHY puts everything RF related out in the field (in the node).
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gitty
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Re: Comcast tests tech that enables gigabit upload speeds over cable

VM said today that a symmetrical gigabit trial is underway.

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Andrew-G
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Re: Comcast tests tech that enables gigabit upload speeds over cable

@gitty There is no RF involved at the CMTS when going virtual/cloud. Remote PHY puts everything RF related out in the field (in the node).

So what exactly is being done at the node (RF mod/demod, I assume), and what is this cloud CMTS doing, and what's the (concept level) traffic routing before virtualisation and after?

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gitty
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Re: Comcast tests tech that enables gigabit upload speeds over cable

The node is equipped with a RPD (remote phy device) which is fed by an ethernet link. It generates the RF. The CMTS is controlling the modems, a piece of software that can be located anywhere.
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Andrew-G
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Re: Comcast tests tech that enables gigabit upload speeds over cable

Fair enough.  Still can't see the case for classic "cloud" as a solution for modem control.  If VM wanted to simplify things and do away with physical CMTS, then the logical solution is to stick that on their own servers at a bit barn on the end of their own backhaul, rather than handing it to some third party who to actually offer much in the way of benefits would need to ship the processing to any DC that has spare capacity.  Seems unwise to even think about that - and as we've all experienced, you can have as many nines as you want for reliability, and that still doesn't stop cloud systems going kaput for reasons outside the designer's risk planning.

If the virtual CMTS does always sit in a dedicated DC local to the cable network's exit points, then that's not (by my view) any form of cloud processing.

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