Upstream congestion?

Man-of-Leisure · 2025-04-03T17:29:07+00:00

With Comcast increasing all low-split upload tiers to 35Mb on residential and business class, has anyone noticed any upstream congestion yet on nodes that haven’t been upgraded to mid-split? Each customer now gets ~ 42Mb of the total ~ 108Mb shared on the node. So far, so good for me it seems. (SB6190 modem)

Man-of-Leisure

MacLeech It’s expensive to build out, license, and maintain the extra bandwidth to have it just sit there unused waiting for an extraordinary situation that needs it. Enterprise customer would pay, but not the vast majority of residential. Providers build just in time bandwidth, often keeping a few months ahead of day to day maximum average usage for residential customers.

This argument doesn’t hold up when it comes to DOCSIS 4.0.

They’re making these expensive upgrades, despite there being no demand for the faster speeds from customers.

No one has been asking for 2Gb or 5Gb upload at home. Most people have no need for 1Gb upload either.

Why? Marketing. They’re losing customers to fiber.

They’re upgrading to DOCSIS 4.0 with the understanding that the upstream will be pretty much unused.

Most people just don’t create that much data at home that they need to upload.

MacLeech

Man-of-Leisure They’re increasing shared capacity for all the customers on the node, beyond that 108Mbps. Evolution.

When you get 2gbps upload, let us know…

computerman2

I don’t upload too much myself

Occasional File to OneDrive or Google drive, but there not huge files most of the time, occasionally

If i’m doing American Truck Sim winter time driving with the Frosty Winter mod in, i’ll use Game DVR so i can record if a crash happens, typically i don’t upload those all that often lol.

Don’t do very much video conferencing these days, i did that more when i was on At&T DSL many years ago, but nowadays just occasional Djing in SecondLife with VirtualDJ program, Streaming Movies, or Music

of course online gaming of Battlefield 2042, Firefighter SImulator, Wreckfest, Forza Horizon 5 at times

But who knows once Mid-split active, i may upload a tad more to Onedrive haha

azdeltawye

MacLeech That GS7000 could be either of the above, and also be upgraded further with rPHY modules in it. You’d have to see inside to know for sure.

So, digging a little deeper into this, I asked a friend who lives down the street from me (served from same node, different output) to share the results of a trace route to 75.75.75.75 and the CMTS MAC from his modem logs:
o Friend’s house - First hop IP: 10.61.223.2 CMTS MAC: 00:90:f0:79:XX:XX
o My House – First hop IP: 10.61.223.195 CMTS MAC: 00:90:f0:78:XX:XX

Looking at these results, it appears that we are connecting to a different vCMTS based on the IP and MAC. Would this be enough evidence to conclude that this particular node is internally split?

MacLeech

azdeltawye Certainly looks that way. Also, those MACs manufacturer are assigned to Harmonic, who makes DAA rPHY node equipment and vCMTS.

Man-of-Leisure

MacLeech They’re increasing shared capacity for all the customers on the node, beyond that 108Mbps.

But why is 6Gb of upstream capacity necessary?

Remember, you said this:

MacLeech It’s expensive to build out, license, and maintain the extra bandwidth to have it just sit there unused waiting for an extraordinary situation that needs it. Enterprise customer would pay, but not the vast majority of residential. Providers build just in time bandwidth, often keeping a few months ahead of day to day maximum average usage for residential customers.

MacLeech When you get 2gbps upload, let us know…

It’s available in like a dozen cities now, and 4.0 amps are available now.

We’ll see the pace of upgrades increase rapidly now that the amps are available.

Until now, they could only upgrade N+0 areas.

MacLeech

Man-of-Leisure But why is 6Gb of upstream capacity necessary?

DOCSIS 4.0 CAN support 6Gb of upstream capacity. It’s not configured for that now (downstream still occupies much of that frequency space) and may not ever be. Just like D3.1 could support over 1Gb of upstream capacity, but isn’t. D3.0 could support over 200Mbps, but didn’t. They can build out the upstream capacity later when needed for utilization growth to keep ahead of congestion.

Man-of-Leisure Until now, they could only upgrade N+0 areas.

Yet, they’ve upgraded more than 50% of their footprint, much of it n+3 or more, with D3.1 mid-split the last few years. They’re going to sit on much of that for at least a few years before upgrading it to D4.0.

Man-of-Leisure

MacLeech DOCSIS 4.0 CAN support 6Gb of upstream capacity. It’s not configured for that now

It doesn’t really matter. Even if it’s only 2.5Gb or whatever it’s doing now, that’s still far above actual upstream usage.

Doesn’t change my argument.

Even if you’re getting 1Gb upload speed, people’s usage doesn’t change overnight.

Most people still do very little uploading at home.

MacLeech They’re going to sit on much of that for at least a few years before upgrading it to D4.0.

Wouldn’t surprise me, since 4.0 is solely for marketing to compete with fiber, not a response to actual demand from customers, or congestion.

Mid-split is more of an urgent upgrade to deal with congestion, and people’s complaints about slow upload speeds.

Though most people still won’t be saturating 100-300Mb upload at home for long periods of time.

Man-of-Leisure

MacLeech Just like D3.1 could support over 1Gb of upstream capacity but isn’t.

Not on Comcast, but Charter, Cox, and others are doing high-split on 3.1.

And I assume a 3.1 modem like the XB8 on Comcast on a 4.0 node could work on high-split, should Comcast decide to allow that.

MacLeech

Man-of-Leisure Not on Comcast, but Charter, Cox, and others are doing high-split on 3.1.

It was an option for them for over a decade. They’re growing into it, but they’re still not using it to it’s full capability. Just in time bandwidth.

Collectively, people do enough uploading to cause congestion and cable providers to increase their upstream capacity. There was more congestion during Covid when there was a rather sudden large increase in traffic, especially on the upstream side due to 2-way video usage, so there were large moves to increase the capacity. Overall, bandwidth use has been on a steady growth slope for decades and providers like to plan ahead so they will have options to deal with it when they need to.

Man-of-Leisure

MacLeech Just in time bandwidth.

But when it comes to DOCSIS 4.0, you have no response.

That’s not “just in time”, and neither is high-split.

People do very little uploading at home.

MacLeech Collectively, people do enough uploading to cause congestion and cable providers to increase their upstream capacity.

They do enough to congest 108Mb shared between dozens or hundreds of homes.

That’s not surprising.

I’d be shocked if nodes congested mid-split, high-split, or 4.0 upload.

That won’t happen any time soon.

MacLeech

Man-of-Leisure But when it comes to DOCSIS 4.0, you have no response.

I already responded. D4.0 won’t get it’s fully configurable upstream bandwidth at launch, it’ll take years to grow into it.

Man-of-Leisure They do enough to congest 108Mb shared between dozens or hundreds of homes.

Enough to get it split multiple times.

Man-of-Leisure I’d be shocked if nodes congested mid-split, high-split, or 4.0 upload.

That won’t happen any time soon.

It’s already happening.

Man-of-Leisure

MacLeech D4.0 won’t get it’s fully configurable upstream bandwidth at launch, it’ll take years to grow into it.

Doesn’t matter, even 2Gb upstream they’re doing now is far above actual needs or usage.

You said they would never build so much excess capacity years (or decades) ahead of actual usage.

MacLeech It’s already happening.

Where?

MacLeech

Man-of-Leisure

Man-of-Leisure Doesn’t matter, even 2Gb upstream they’re doing now is far above actual needs or usage.

Some want it and use it. Clearly although it’s a small minority there is a demand for it as the majority of the providers who can offer it do. There is a bell curve in the tiers offered and subscribed to, with the low and high ends being a minority of subscribers while the majority is in the middle. Same as most products.

Man-of-Leisure You said they would never build so much excess capacity years (or decades) ahead of actual usage.

They activate enough bandwidth to support the tiers they offer, even though the system can support much higher amounts of bandwidth. Why is that concept so difficult for you to understand?

They don’t activate 6gbps, they activate 2gb. Just like with D3.1 they didn’t activate 1gb, they activated 108mb, moving to 250mb, with some finally getting to 1gb at the end, after more then a decade of it being an option.

Man-of-Leisure Where?

Where those upgrades have been launched. There are always service groups that need more bandwidth as usage always grows as there are always a minority that will use everything available. Just because you can’t contemplate it happening doesn’t mean it doesn’t happen.

Man-of-Leisure

MacLeech there is a demand for it as the majority of the providers who can offer it do

No, it’s purely for marketing, so they can claim to be “the fastest”.

Doing expensive upgrades for the 1% of customers asking for those speeds wouldn’t make any sense.

People have wanted faster than 35Mb upload for over a decade now. Why didn’t they do it back then?

Far more than 1% have been asking for faster upload speeds.

MacLeech Where those upgrades have been launched.

Source? Proof?

lesmikesell

Man-of-Leisure No, it’s purely for marketing, so they can claim to be “the fastest”.

Marketing is what matters. Why are you surprised or even commenting on that?

MacLeech

Man-of-Leisure Source? Proof?

You really think all ~ 200,000 nodes across multiple providers that have been upgraded in the last 4 years to mid, high, or D4.0 haven’t seen ANY congestion since they were upgraded from low-split? I wish I could be so optimistic/naive, but I can’t. There have been multiple anecdotal reports across social media from techs involved and customers who’ve noticed. DSLR had a few. Some here on BBF have noticed.

Also, 25 years of experience in the broadband industry, involved in multiple generations of upgrades and multiple contacts directly involved in such upgrades tell me so. Users always find a way to use the service available, some to the full extent of what they have available. Some here want it just for their massive uploads.

If you’re looking for public reports from the providers, wait until the next SCTE conference.

Check here for some statistics on broadband usage growth:
https://openvault.com/resources/ovbi/

videomatic3

haha sweet. you also gotta remember that those numbers are limited too… at least in the upstream because doing 5.5tb of upload with 35mbit is literally maxing it out for half the month.

im pretty sure the one time i set a record using over 100tb in a month, i had no real good reason to do it though.

Man-of-Leisure

lesmikesell Marketing is what matters. Why are you surprised or even commenting on that?

Spending billions on network upgrades for marketing and having most of the bandwidth sit there unused seems like a waste of money to me.

If customers aren’t using it, spending the money on upgrades seems silly to me. No one’s asking for 10Gbps at home, or even 5Gb or 2Gb.

Coax still has lots of untapped capacity, so technically most of it is currently already being underutilized.

It can be pushed to 3GHz, and CableLabs has already mentioned that 6-7GHz is working in the labs now.

lesmikesell

Man-of-Leisure Spending billions on network upgrades for marketing and having most of the bandwidth sit there unused seems like a waste of money to me.

Selling subscriptions is what matters. If you sell something that isn’t used, so much the better.

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