Switching to Cable from Fiber:Cable Modems, Channel Bonding, DOCSIS 3.1, Powerline and ISP anecdotes

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Lightgreen Senior Member • Posts: 2,145
Switching to Cable from Fiber:Cable Modems, Channel Bonding, DOCSIS 3.1, Powerline and ISP anecdotes

So, I recently transitioned from my local telecom companies fiber to home offering, which is very economical, back to the dreaded Comcast and boy have things changed.

I'm a story teller, warning, story coming, scroll down if you want technical details to Summary. Also, I'm writing this as even DSL reports and others do not cover this issue adequately enough as to be blunt, this gets really technical and few understand it and just take others word for things rather then test for themselves.

First up, my fiber to house offering, although a symmetrical offering, that is I got the same speed up as I did down vs the traditional 10 to 1 down vs uplink speed of a cable provider, very impressive, except for the end of my time with my fiber to home service, my local telecom provider started experiencing very Comcast-like issues where during peak hours (dinnertime) my internet would slow, and at times, halt completely for minutes at a time. When I mean halt, I mean no ping google halt. Like double huh status.

I immediately suspected it must be me a software update, a bad connection on my LAN, etc etc etc. Nope nope nope. I tied directly into my fiber during one of these outages, sure enough, I couldn't get through, and even my fiber provider had trouble issuing an IPV6 for that matter. That's bad. Nothing to NAT too.

Many calls to the ISP later, they denied they had a problem, spoke to their NOC, double denial, local tech came out and did a speed test during non-peak hours (gee that'll tell you alot *sarcastic*) finally cancelled and jumped to Comcast. I had 30 days to try em no commitment. They've gotten better to my surprise.

So if you haven't been following, cable providers like Comcast have been steadily increasing their pipe to accommodate both bigger connection packages like gigabit, and deal with traffic congestion. The catch, you need a modem that will address the new channels they've added. You can lookup if you area has 16, 24 or 32 channels yet on various forums too...


Those days of dinner time outages on cable internet? Gone, if you bring your own modem / cable gateway router combo that can negotiate to all those channels that is.

So to break it down in layman terms, although you need say 24 channels to get 960mbs connection, lets say you have a 50mb connection like me, well that's 24 lanes of freeway in which to squeeze that 50mb through, even if that 24 lane freeway gets busy, no problem. More channels, more resilience against traffic congestion. I get 72mb, solid (I thought you said you have a 50mb connection, why yes I do) More on that in a bit.

So I noted my area has 32 channels down available, I picked up a Netgear CM700, it can do 32x8 right? Sure. Called up Comcast, activated, ran both ISPs in parallel for a few days, cancelled my telecom fiber to house. Poof.

You'd think that'd be the end of the story, not quite.

Being anal about technology, I noted sometimes my connection still exerted issues, I couldn't put my finger on it. I noted, my CM700 was negotiating 31 channels down and 2 channels up. That latter part is a problem. If, you only have 2 channels up, and those 2 channels have a problem, doesn't matter how big your down pipe is, you can't ask your ISP for data, your ability to request data gets chocked off. I suspected that must be the culprit since your run of the mill speedtest benchmarks weren't concluding an issue.

So I found after testing multiple coax connections in my house, the one on the far side gave me 4 channels up and 31 down. Sure enough, my internet was REALLY fast on it. The only problem is, that room is on the far side of my house. Only 2.4ghz was making it to the other side of my house, the good juicy 5ghz wasn't making it. Well, I looked at wiring my house for CAT6, except, I found my attic was not so easy to do that in since the last time I wired my old house 10 years ago. I'll skip that part of the story and say I went another route. Repeaters.

I found joining an extra ASUS RT68U on the 2.4ghz band to my other 2.4ghz RT68U gave me a solid link, and I slaved everything but the 2.4ghz printer off the 5ghz, but my latency jumped by about 5-10ms, once again me being anal, I don't like my technology being even semi perfect.

I looked hard at Powerline, except, guess what? More research I did, uncovered another devil in the details, Powerline, has latency too! More then wifi in many cases I might add, which makes sense between electrical noise, those powerline adapters have to translate and encrypt/decrypt data, it's not a raw copper line, sorry.

Well I ran the issue past one of my colleagues, and he indicated I should bypass my coax in my house entirely, go to my cable box on the side of the house directly and tap my modem straight into it, and then run CAT5/6/whatever from it. Brilliant. I noted my fiber to house provider had run a CAT5E from the telco box on the side of my house through the garage to my washroom but it's box was right next to my cable box. I drilled a whole through my garage wall to the box to accommodate the larger coax which I took off the splitter and ran through the hole into my garage and I stole it's CAT5E off it's box, slapped both on my modem which I have in my garage and tied my Router back where it used to be in the washroom. Bang. 20DB improvement in signal. That's alot folks. Except, when I relocated my cable modem from my living room where it was getting 31x2, somehow, it went belly up. Probably a loose connector on the board, bad craftsmanship. Returned the modem for an Arris SB6190 at Bestbuy.

Called up Comcast, they indicated they just bumped everyone from 50mb to 60mb, I gave them the MAC to my new modem, activated it, and had me test it, 72mb, wow!

...But, my internet was slower now? What, huh?

For the next day or so I couldn't explain it, but webpages loaded slower, my Amazon and Roku TVs were more angry, yet speed tests gave all clear.

I discovered Puma 6 class action lawsuit. Aha!

Both my former Netgear CM700 and Arris SB6190 have a chipset known as the Intel Puma 6, it's a favored option for 32x8 bonded modems as Broadcom, the former heavyweight of cable modem DSPs, skipped DOCSIS 32x8 3.0 and went right for DOCSIS 3.1 32x8 leaving Intel the only slice of the 32x8 3.0 pie.

Well, after much pain and research, turns out although both the Arris SB6190 and Netgear CM700 have Puma issues, which I had the update for both, as it turns out, the update doesn't completely correct the issue. Side note, the Netgear CM700 has a processor, twice, as powerful as the Arris SB6190, hence it was faster, even though it too has a Puma in it. The SB6190 has a dual core 600mhz Puma 6 vs the Netgear CM700 has a 1.2ghz Puma 6 in it. That's why it wasn't my imagination that I went backwards in performance even though I gained another 2 channels on the uplink.

Returned the Arris SB6190 and bought a Netgear CM600.

Now you might ask why I didn't do the Arris SB8200 that's on that $149 sale at Amazon right now, or a CM1000 that if you're lucky your Costco still has in stock for the same price (both of which have Broadcom processors in em, hmmmm, almost like Arris and Netgear knew something was up). Good question, good answer coming.

Comcast over provisions your link by 20%, hence my 60mb connection was getting 72mb. Except, if you have a DOCSIS 3.1 modem They're ironing out the bugs right now with it. If you use a DOCSIS 3.1 modem, you're stuck, at whatever they gave you. Hmmmm.

So next best thing, what's the best Broadcom modem, that's DOCSIS 3.0 compatible? You guessed it, the 24x8 Netgear CM600!

Well I swapped it out, and wow, I've never had this fast of internet ever, anywhere. Bang, instant.

I did note, my sockets take a bit to negotiate, and sure enough, I noted, that CAT5E run? It's negotiating a 100mbit connection even though CAT5E can do 1000, one of the pins needs to be re-terminated, looks like the tech that did it was a bit sloppy.

But, I had an ephinay, I can't run my cable modem in my garage during the summer. Why? Uh, we get 100+ degrees during the summer. So now what?

Later this week, I'm going to play musical chairs, strip off the splitter on the main cable connection, find which of the 3 goes to my living room, and just taking the splitter off should give me enough DB to get my 4 uplinks in my living room, even though my coax in the house is crap. Since comcast only support 4 up right now, done. That'll solve both my environmental issues, and I'll run my own CAT6 from the modem to my router in the living room again. Really I could've taken the splitter off to begin with, but I wanted to be anal. I only need enough signal to get the other 2 channels on the up, 20DB more is overkill, right now.


Couple morales of the story...

Your cable company is worth a revisit, if, you buy a high end bring your own modem to save on the fees and negotiate all of those juicy new channels which negate the dinnertime problems on cable internet of old.

Most people, unless you have a gigabit connection you're paying for, the Netgear CM600 is "the" modem to get. Otherwise if you do have a high end connection, IE the highest end, the SB8200 or CM1000 are good options. But, even then, the CM600 could be better as it has more support from the ISP as they're still adapting to 3.1 as we speak. The Netgear CM600 (and other non 3.1 modems) if you're using a non highest offering plan, will get a 20% freebie, too.

Avoid Puma 6 modems like the plague. Even if you're not a gamer, you'll appreciate the performance bump. Even the new fix, only partially addresses the issue. My older CM600 is ALOT faster then a new, patched CM700... Let me confirm that for the technically oriented folks, the patch, doesn't not completely solve the issue. A 2015 modem is FASTER. Period.

Removing splitters, if you do internet only, and don't do TV (I do bunny ears / over the air antenna) will give your cable modem more signal to play with. Removing it from the cable box is a good idea, but you need to figure out which cable goes to the drop your modem is on.

Powerline adapters have latency, warning. Wifi repeaters are actually better in many cases except sprawling apartment complexes in San Jose, where I used to live I might add.

Side note, 2.4ghz has more penetration of buildings/longer range then the newer 5ghz band. And, the ASUS RT68U (which I own) has the best 2.4ghz and 5ghz range, period. Also has the best range, and speed on 2.4ghz, which your iPhone/smarphone usually chooses for the reasons above since it has a lesser gain antenna anyhow. Why the older RT68U is better is probably because it was made before some more strict regulations went into effect regarding signal strength by the FCC / the RT68U also came out around the peak of 2.4ghz where newer routers are now focusing on 5ghz max performance, which isn't a bad thing, but having a single router, is better then repeaters if you can do it.

Lastly I kept this pretty high level, I can talk to the weeds of cable termination, socket negotiations, latency, jitter, various chipsets, network topology, yada yada yada if anyone even appreciates this thread. Google will

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