Your experience with Comcast/Xfinity Internet

[john321]

How's your experience with Comcast Internet service?

So far, mine sucks. This thread is NOT about the terrible customer service. I am interested in the following:

• Up-time - do you have problems with your Internet service being disrupted?
• Throughput - does Comcast/Xfinity consistently deliver the bandwidth you pay for?

I moved from an area which was serviced by Brighthouse Networks. With Brighthouse, I experienced complete disruptions in service only three times in 17 years. One of those was due to a hurricane. The other two were due to a dead modem.

I've been with Comcast for less than two months. So far, I've had complete disruptions in service at least five times. I've tried two brand-new modems (different manufacturers).

I have two HDHomeRun PRIME tuners and a modem. There is only one cable jack in my apartment (same as in my previous apartment, on Brighthouse), so all three devices are connected to a single jack. I have tried several combinations of splitters and taps. With every combination of splitter and taps, the downstream signal has been between -4 to +3dB, and the upstream signal has been around 45dB... both of which are well within spec.

I tried a balanced 3-way splitter with a -5.5dB drop on each output. I tried an unbalanced splitter with -3.5dB to the modem, and -7dB to the tuners. I tried a "tap" that is supposed to split the frequencies needed by the modem... to the modem, plus a 2-way splitter with -3.5dB to each tuner.

In each case... the tuners worked perfectly. The modems (I tried two, brand-new modems... two different brands... two different models) would work perfectly for a day or two. The signals on the modem's internal webpage looked perfect. But, after a day or two... the connection would be dropped. The only way to get it working again... was to disconnect the modem and connect it again.

After messing with this for several weeks... trying every combination of splitters, cables, etc... I finally decided to connect the modem directly to the wall jack.

It stayed connected, consistently, for more than a week.

Even though the signals (when connected, and working) with the splitters always looked perfect... I decided to buy a unity-gain bi-directional amplifier with an active return.

Ever since then, my modem has remained connected... without needing to be power-cycled.

Now, just to remind you... the tuners have never had a problem throughout this whole ordeal. They have ALWAYS been able to tune a channel.

But... what I have noticed is that I frequently have a substantially slower throughput than what I pay for.

When I was on Brighthouse, my subscription included 60Mbps download, and 6Mbps upload. I always got exactly that, even during peak periods, such as evenings and weekends.

Since being on Comcast, I have noticed substantial slow-downs. Even browsing simple websites can be slow. So, today... I measured it.

My subscription is for 90Mbps download, and 6Mbps upload. During peak times today, using Comcast's "on-network" tool, speedtest.xfinity.com (which proves that it is being limited by Comcast's network, and not some "external" network load), I would get a short burst of download speed near 90Mbps... but it would quickly slow down to around 6Mbps. The test took so long that I didn't wait for the upload test.

That's less than 7% of what I pay for!

What's your experience with Comcast's Internet service? Do you get the bandwidth that you pay for?

[john321]

I should also mention that I spent many hours on the phone with Comcast. In each case, disconnecting/reconnecting the modem magically made everything work. (referring to connection, but not bandwidth)

The signal strength and quality, both downstream and upstream is absolutely perfect... when the modem works.

The only thing that FINALLY prevented the modem from completely disconnecting was when I replaced the splitter with an amplifier.

The "slowdown" happens even when the modem is connected directly to the wall jack, so it isn't caused by the splitter/amplifier.

I think that Comcast simply doesn't have enough bandwidth for the subscribers in my area. At times when lots of people are home... bandwidth sucks. At times when most people are sleeping or at work... I get amazing bandwidth (more than I pay for)!

Has that been your experience on Comcast/Xfinity?

On Brighthouse, I always got what I paid for... no matter what time of day or day of week.

It is incredibly frustrating when Comcast's bandwidth goes down so low that I can't watch something on Netflix, Amazon, or even CBS.com or NBC.com.

I tried watching an episode of "The Blacklist" on NBC.com (an episode that didn't record due to my move). NBC's player shifted me down to the lowest resolution... and it still kept pausing and had jerky playback.

I have never experienced such terrible playback. Obviously, Comcast has "oversold" their Internet service in my area, and they need to upgrade.

[john321]

The attachment in this post is what I typically see with the unity gain amplifier connected. You might notice, that with the unity-gain bidirectional amplifier... I get +7dB downstream, which is still within spec, but "hotter" than what I got with splitters and taps. However, I still get the "slowdown", even with signals that look like this.

[john321]

Right now... it's late. Very few people are streaming stuff. So, the attachment is what I get now. I will try to post an image when it is down to 6Mbps download later.

[DOS4EVER]

Sorry to read you're having problems. I have never been disappointed with my Comcast internet. My speeds are always consistent with what I pay for and it rarely goes down. When it does go down, Comcast is quick to fix. I have had the very reliable Motorola SurfBoard modem for six years. That sucker just stays working.

[bob_p]

I've had Comcast for years - and, overall, Comcast has worked pretty well for us. A few comments...

We live in an area with many new homes built in the last few years. As more subscribers are added in an area, it appears the "neighborhood node" can get overloaded. I've had this in two neighborhoods - with both Comcast and TWC. The symptom of this situation is that network bandwidth is great during times when other people aren't online (such as in the middle of the night or the middle of the day during the week) - and bandwidth drops dramatically in the evenings, when neighbors go online. In both cases, it appears what the cable company did was to "split" the neighborhood node to provide more bandwidth. And after that was done, the bandwidth was fine.

Another problem I've seen is low signal. This can be caused by several reasons. It appears that signal strength varies over the day - so it's possible that there will be times when the signal strength and quality are fine - and other times when the TV signal will be "glitch" or digital channels can't be tuned - or the Internet bandwidth drops significantly.

If you have a home that had cable installed years ago, it's possible the cable going to the house has been damaged (ants?). And replacing that cable can solve signal strength and reliability problems.

What has happened more often is that in servicing other homes in the area, they may have done something that lowered your signal strength - either because the signal was too high elsewhere (so they lowered the strength) or they've done something to the connections which inadvertently lowered your signal strength.

The configuration that's worked pretty well for us is connecting the cable modem as close to where the signal comes in as possible - and then adding a variable amplifier on the connection that goes to the TVs/digital tuners. The model seems to stay pretty reliable - but we will at times see problems with the digital tuners (which seem to be more finicky), and I'll occasionally adjust the amplifier up or down, which fixes the problem.

When I had the neighborhood node problems - I eventually had to get the cable company to make a service call. When signal problems vary based on time of day, I had to schedule a call during one of those times, so they could see what was happening. If they see that your signal strength is too low, then they should make whatever changes are needed (including providing an amplifier) to get the system working correctly. If the problem is an overloaded neighborhood, it may take them longer to address the problem - and it can help if you have neighbors also complain about bandwidth problems - if they are seeing the same thing. In the two cases when I encountered this problem - it was both in areas with many new homes being added quickly - and it took several months each time to get the cable company to admit they had a problem - and schedule the service upgrade.

Overall, our Comcast service has been working well. Internet performance has been very good - and once we solved the node and signal strength problems, the system has been pretty reliable.

[john321]

I've had Comcast for years - and, overall, Comcast has worked pretty well for us. A few comments...

We live in an area with many new homes built in the last few years. As more subscribers are added in an area, it appears the "neighborhood node" can get overloaded. I've had this in two neighborhoods - with both Comcast and TWC. The symptom of this situation is that network bandwidth is great during times when other people aren't online (such as in the middle of the night or the middle of the day during the week) - and bandwidth drops dramatically in the evenings, when neighbors go online. In both cases, it appears what the cable company did was to "split" the neighborhood node to provide more bandwidth. And after that was done, the bandwidth was fine.

Another problem I've seen is low signal. This can be caused by several reasons. It appears that signal strength varies over the day - so it's possible that there will be times when the signal strength and quality are fine - and other times when the TV signal will be "glitch" or digital channels can't be tuned - or the Internet bandwidth drops significantly.

If you have a home that had cable installed years ago, it's possible the cable going to the house has been damaged (ants?). And replacing that cable can solve signal strength and reliability problems.

What has happened more often is that in servicing other homes in the area, they may have done something that lowered your signal strength - either because the signal was too high elsewhere (so they lowered the strength) or they've done something to the connections which inadvertently lowered your signal strength.

The configuration that's worked pretty well for us is connecting the cable modem as close to where the signal comes in as possible - and then adding a variable amplifier on the connection that goes to the TVs/digital tuners. The model seems to stay pretty reliable - but we will at times see problems with the digital tuners (which seem to be more finicky), and I'll occasionally adjust the amplifier up or down, which fixes the problem.

When I had the neighborhood node problems - I eventually had to get the cable company to make a service call. When signal problems vary based on time of day, I had to schedule a call during one of those times, so they could see what was happening. If they see that your signal strength is too low, then they should make whatever changes are needed (including providing an amplifier) to get the system working correctly. If the problem is an overloaded neighborhood, it may take them longer to address the problem - and it can help if you have neighbors also complain about bandwidth problems - if they are seeing the same thing. In the two cases when I encountered this problem - it was both in areas with many new homes being added quickly - and it took several months each time to get the cable company to admit they had a problem - and schedule the service upgrade.

Overall, our Comcast service has been working well. Internet performance has been very good - and once we solved the node and signal strength problems, the system has been pretty reliable.

OK, so... what you are saying is that Comcast needed to provide more bandwidth in your neighborhood???

This is definitely NOT a problem with signal strength nor signal quality. It is definitely about bandwidth.

I believe that Comcast needs to provide more headend nodes in my neighborhood.

[bob_p]

Signal strength and bandwidth can be separate problems.

Signal strength is impacted by the connections between the home and the neighborhood node. Problems with any links in that connection can affect signal quality and strength for those homes sharing that connection. And because any time they do service on the links between our home and the neighborhood node, there is a risk that the signal strength might increase or decrease, having a variable amplifier provides more control at the home end, without requiring a service call from Comcast to fix problems should the signal strength be too high (which is a problem) or too low.

If a neighborhood node is overloaded because it is serving too many homes - signal strength and quality could be excellent - but bandwidth will dip considerably when more users are on the network. When this happens, the cable company has to upgrade the neighborhood node to provide more bandwidth, which may require "splitting" the node into two or more new nodes. That's what appears to have happened in my last two neighborhoods when I was bandwidth drop dramatically in the evenings. And once they fixed the node - bandwidth has been great.

It can take persistence with the cable company to get these problems fixed - especially when the problems are intermittent. The cable company usually will do their service calls during the day - and in many cases the signal and bandwidth problems may only happen in the evenings - so getting them to send out service at those times - or at least monitoring the service in the evenings may be the only way to get them to fix the problems.

If you are having problems - my recommendation is to do some measurements at different times of the day and different days during the week. And if you can find a period when the problem is the worst, then try to schedule the service call at that time - so when they come out, they can see the worst case performance, which should make it easier for them to find the cause of the problem.

And, when you are seeing signal quality problems - look at the signal strength level on your end. Your signal strength needs to be in the acceptable range - too high or too low will cause problems. At times, I've seen the need to add an amplifier. And, I've also had cases where the signal strength was too high - and I had to pull the amplifier off and add a splitter to drop the signal strength down.

Plus, before you have the cable company out - make sure that there isn't anything on your end causing the problems. Remove everything from your connection - and connect your TV or cable modem directly to the outlet - and verify that you're having problems before connecting your splitters, cables, devices and amplifier.

[john321]

Bob, you and I are in agreement. You just said it in many, many, many more words than I did in post #7.

[john321]

So, has anyone else experienced throttling with Comcast during peak times?

I never had it happen during my 15+ years on TWC/Brighthouse. I am beyond angry that I get less than 10% of what I pay for during peak times on Comcast.

Does anyone have a similar experience on Comcast?

[bob_p]

Are you sure it is throttling? Or that your neighborhood is overloading the network?

I suspected I had throttling when I was getting lower than expected speeds in the evenings - and it turned out to be an overloaded network.

If you're getting only 10% of the expected bandwidth during the evenings or weekends - call Comcast when that is happening - and have them look at the network links going to your house - and they find the bottleneck.

[john321]

Yes, I suspect that the Comcast network is insufficient for my neighborhood. The same thing happens when I am on XFinity Wifi anywhere within a mile or two from my house.

I will call them about it, but I am still angry either way. Less than 10% of advertised bandwidth is terrible.