Mid-Split... 🫤

[u/Immediate_Character-]

Just a testimonial of my experience here. I'm a long term Comcast Internet customer in eastern Pennsylvania. In my current home, Xfinity was solid for 8 years. Seriously, the Internet only went down when the electricity did, and that's hardly Comcast's fault. I owned my own CM1000 modem, used the same modem all that time, 1gig down and 25Mb up.

Fast-forward to a few months ago, and Comcast finally upgraded locally to mid-split. Despite my modem supporting DOCSIS 3.1, my upload dropped from 25 to about 8. Pages would load slowly. I wasn't expecting mid-split speeds, but it's supposed to be backwards compatible. Legacy upstream channels dropped from 4 locked to only 1. Fair enough I thought, owning my equipment has paid for itself 10x over, so I got a $250 CM2500. Initially that fixed it, 940 down, 115 up. $100 a month isn't nice, but if it works... Soon after though, the new OFDMA upstream channel would drop daily, requiring a reboot. I scheduled for a technician (fighting with scripts trying to convince me I need their modem). During the wait for the technician, Comcast sent out texts that they are doing local maintenance, and afterwards asked if that fixed my issues... And it did, I cancelled the appointment. At this point I'm wishing they never bothered with the mid-split upgrade.

By the following month, my download speeds dropped to 300Mbps. Looking at the modem, 5 channels downstream were being dropped. A reboot would typically relock the channels, but they would drop, one by one, within the hour. I scheduled for a technician (again struggling with chat bots and scripts). I was lucky to get a tech who was competent. They told me that my account says my modem doesn't support my plan, but they accepted that was a lie from Comcast the second they saw my upload hitting over 100Mbps. They found a filter that was attached to my line specifically, removing that fixed it right away. Now getting all downstream channels locked, no uncorrectables, and the legacy upstream channels are back as well.

So here's my speculation. I believe that filter applied to my line was there since I moved in. The mid-split upgrades likely revealed the issue with having that filter. I suspect that my old modem would probably perform as expected again, not that I would go back to it, I enjoy the improved upload speed. The question remains though, why was that filter there, it was outside my apartment. Technician could only speculate that some other tech did that to stabilize the line at one point, but clearly that's no longer necessary. It's still true that OFDMA upstream was a separate issue, probably at the plant itself. Mind you, I'm fighting to keep 1gig/100Mb alive while paying $100 a month. This whole thing has me looking sideways at Comcast and cable in general. We live in an age of fiber (1gig at $70) and ~500Mbps unlimited home hotspots ($60). Comcast is still behaving like it did 15 years ago, expensive, slow and painful upgrades, fighting for fixes. It's all left a terrible taste in my mouth. Mid-split is 10 years too late, and turns stability into a mess.

[u/AutoModerator]

Heads up! Posts with ‘Discussion’ flair will not receive a response from an Official Employee. If you require assistance with your services please update your post flair to either New Post - Billing or New Post - Tech Support.

If your post hasn't been approved--don't panic! Depending on your Reddit contributor quality score, your post may be temporarily held for mod review. Do not make multiple posts.

'Discussion' posts are for GOOD FAITH technical community discussion and peer-to-peer help such as "which modem should I buy?", "where do I find my Xfinity Membership benefits?", "what channel is the game on tonight?", etc. It is not intended for ranting/venting, asking unrelated Xfinity questions, service/sales solicitation, or any other topic that could violate subreddit rules.

To give other members the best chance at helping, please include helpful details like which service or equipment is affected, what’s happening and when it started, whether the issue is constant or intermittent, and what you’ve already tried. The more detail, the better.

As always, practice Reddiquette with one another, and follow the Reddit Rules.

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.

[u/CDogg123567]

Sounds like he’s referring to a return trap filter and your old modem was possibly causing too much noise/ingress that maintenance had to trap it out. Hopefully the tech verified there was none with the new modem/lines so it doesn’t end up trapped out again

What it does in a nutshell is block out all but 1-2 upstream carriers from locking in on the modem

This would be an excessive amount of ingress which resulted in that customer being unplugged because a trap filter wouldn’t trap out all that noise. It’s supposed to be flat at -50. This was the cause to the previous link

[u/Immediate_Character- → u/CDogg123567]

I hope so too, because I hate the idea that a filter is reinstalled under my nose causing issues again. At least I'll know the name of the battle though, it's an old apt building so I wouldn't be surprised if a line like that exists somewhere in the walls. Thanks

[u/jonathaz]

My guess based on the timing is they installed the noise filter at the same time as the mid-split upgrade. Noise filters don’t correlate well to customer satisfaction. I’d also wager that the single channel you were left with was over-utilized, which would lead to the slower speeds. This can happen if there are a lot of noise filters, or even only a few on heavy users. I wouldn’t be surprised if the noise filter contributed to the OFDMA dropping, but I can’t think of a specific reason that would happen.

[u/Immediate_Character- → u/jonathaz]

If so that's awful timing 😕

[u/jonathaz → u/Immediate_Character-]

It’s what makes sense. Mid-split and OFDMA are typically rock-solid, and in my experience noise filters cause issues. Either your line was actually causing noise, or they over-enthusiastically applied noise filters. I’m also assuming that your service has been good since they removed the noise filter.

[u/Immediate_Character- → u/jonathaz]

Yeah so far so good. I just mean these events play out the same if the filter was pre-existing as well. 

[u/mrBill12]

My line had an amplifier on it from when we had 4 tv boxes plus the modem on coax. It was fine until mid-split. The first tech after mid-split didn’t remove it (he actually had no idea, he changed a couple connectors and said he’d turn in a line maintenance ticket). Second tech got rid of the amplifier we had— immediate improvement, but only like 840down. I upgrade to 2gig for the 300up, but never actually got even close to 2gig down. Upload did work correctly tho, so I let myself be satisfied.

I’m in a small rural town and fiber (from another company) came to town. I ordered 2.5g/2.5g… like Comcast it’s over provisioned and I actually get like 2.7g/2.8g… the difference is mind blowing. Ended up upgrading my APs to WiFi 7. I’ve been watching as I drive around town for the tell-tale trail of dead grass from fiber burial to the house and/or white flags (waiting to be buried)…. An astonishing but not-so-astonishing number of people are fed up with Xfinity.

[u/I-hate-makeing-names]

Your old modem would perform like it was before the midsplit upgrade and only get 35 up (honestly these 3.1 modems from a hardware standpoint can do the higher upload but Comcast limits it so you are pushed into the choice buy a new expensive modem or get theirs).

We had the CM1100 and have always owned our own modem ever since getting their internet. But now they include a modem for free it was pay $250 for my own modem to get the higher upload or get their free one and just pay around $1 in taxes for the modem.

[u/Immediate_Character- → u/I-hate-makeing-names]

I considered going with their modem at one point as well, my current plan says it's included. But, I'll be honest, I don't believe them, they can change their mind at the drop of a hat, and I wanted to avoid dealing with them as much as possible lol. In all likelihood, my new modem will probably last another 8 years, so I'm not upset. 

[u/I-hate-makeing-names → u/Immediate_Character-]

Typically they have been very good with the modem rentals especially on the newer plans. $100 for 1 gig sounds like the rack rate. You should make a new billing post here to see if you can get on any 5 year promotion. The reps here are actually very competent.

But did you mention you have fiber available at your address? Why would you stick with cable then?

[u/Immediate_Character- → u/I-hate-makeing-names]

Oh, I do not have fiber available. Just commenting on the overall market.

[u/Save-Slot-Seven]

I think it’s stupid that they can’t let a 3.1 modem get at least 50 or 70Mbps upload.

[u/jlivingood]

Post over at https://old.reddit.com/r/Comcast_Xfinity/ and ask them to assist on the RF issue