Re: [Astlinux-devel] Comcast/Xfinity DOCSIS 3.1

[Lonnie A. <li...@lo...>]

Doing some research and reaching out to "dslreports" forums, it does appear that a DOCSIS 3.1 modem (with 3.1 infrastructure) does offer more robust IP transport ... somewhat less latency and jitter.  DOCSIS 3.1 uses a better error correction method, Low Density Parity Check (LDPC), which is implemented in DOCSIS 3.1 modem hardware.

The question is whether it is worth upgrading now, or wait for your ISP to give you an incentive to upgrade to a DOCSIS 3.1 modem.

I'll probably look at getting a DOCSIS 3.1 modem shortly after 3.1 is available in my area, keeping the same download speed plan.

Lonnie



> On Aug 4, 2018, at 10:04 AM, David Kerr <Da...@Ke...> wrote:
> 
> That is exactly the question I am asking myself.  Is it worth it.  I can understand why the ISP would want me to upgrade (spread customer load across many more channels) but it is not at all clear why I would want to upgrade.  I agree latency and jitter is more important than raw bandwidth, I have plenty of that (download at least).
> 
> David.  
> 
> On Sat, Aug 4, 2018 at 10:56 AM, Lonnie Abelbeck <li...@lo...> wrote:
> 
> > On Aug 4, 2018, at 9:08 AM, David Kerr <Da...@Ke...> wrote:
> > 
> > Comcast/Xfinity have been bugging me to upgrade my cable modem for the past few months.  Started with emails, now getting telephone calls, stating that my current modem cannot take advantage of their latest technology upgrades.  I'm assuming they have rolled out DOCSIS 3.1 into my area.  I'm not sure I am going to do it yet but looking at the options there are basically three to chose from, Netgear, Arris and Motorola.
> > 
> > Ok, so the point of this post... the Motorola claims to support up to 2Gbps download by channel bonding two 1Gbps ethernet ports.  Of course Comcast doesn't have anything like that speed support but it does prompt the question as to whether Astlinux could channel bond two ports into EXTIF.  And of course it would need to also bond two ports for INTIF that would need to connect to a switch that supported bonding.
> > 
> > Clearly not something needed anytime soon, but I am curious.
> > 
> > Thoughts?
> > David
> 
> My ISP (COX) will be turning on DOCSIS 3.1 any day now in my area, I'm not interested in DOCSIS 3.1's 1 Gbps down (only 30-ish Mbps up).  Currently I have a 50/10 Mbps business connection and other than running speed tests I can't think of a time I noticed where the complete data path was limited by 50 Mbps.  Over time this will slowly change and then 100 Mbps may be useful.
> 
> Personally, the quality of the connection ... low latency, low jitter, low downtime is far more important to me than down speed greater then 100 Mbps.
> 
> So, how does a DOCSIS 3.1 modem perform (latency and jitter) on DOCSIS 3.1 infrastructure compare to a 3.0 modem on the same 3.1 infrastructure ?  I have yet to find an answer to that question.
> 
> Also beware that some DOCSIS 3.1 modems use an Intel Puma 6 chipset with a lot of problems.
> 
> Also beware COX residential (and Comcast I think) currently have a default 1 TB data tier, so at 1 Gbps 1 TB of traffic occurs in 133 minutes.
> 
> So David, I don't think ethernet bonding is worth worrying about. :-)  10 Gbps NIC's will probably be ubiquitous when we need such a thing.
> 
> But, since a DOCSIS 3.1 modem will aggregate a lot more channels than a DOCSIS 3.0 modem (on 3.1 infrastructure) would a DOCSIS 3.1 modem be a useful upgrade for a plan speed of 50-300 Mbps ?
> 
> Lonnie