Lend me your BS meter: help me grok this Comcast biz advice

[gigatexal]

so I was at a clients fixing their internet. It was all supposed to be really straightforward but it wasn’t. The setup is this:

Comcast biz class modem plus switch plus wireless-ac all in one. The guy said it was likely their Cisco based hardware.

One of the ports is hooked up to a later 2 dumb netgear switch that operates as a port multiplier more or less. A credit card processor is hooked up to it, and some other devices. Simple enough.

Everything else: 4 to 8 cell phones with a 75% / 25% split from iPhone and androids. There are also 2 to 3 computers connected. The iMac in the front desk. The main doctor’s laptop and maybe one or two more. Also there’s a square reader for credit card payments and a printer connected to WiFi.

The line is a 50mbit down 10mbit up line.

My question to the tech was is there such a thing as an arbitrary limit to the number of clients that can be connected to the WiFi? Would one or two clients grabbing all the bandwidth to cause other clients to drop off? I was testing it today and with no real load it seemed that packets were being dropped for no reason. Some websites worked while on WiFi but it was great when one is wired direct to the modem.

The above was what the Comcast biz tech said was the cause. Thoughts?

I’m going to suggest a downgrade to a dumb modem plus a pfsense firewall and then a bridged WiFi access point.

 

[compuwizz]

There might be a limit of the number of clients allowed just due to DHCP IP pools. However I would highly recommend your solution of putting in either a pfsense or Ubiquiti router then an standalone wireless AP.

The customer is likely seeing wireless interference in the office and the all in one modem isn't automatically migrating to a new channel. Many of these all in one modems also run the PUMA 6 Intel chipset which has its own long list of bugs compared to Broadcom based chipsets.

 

[BlueLineSwinger]

Also, is it possible that Comcast uses their business-class installs for their Xfinity wireless service, like they do for residential? Any clients connected through that to the client's modem/router could possibly be crowding out "legitimate" wireless traffic (supposedly such users don't count towards bandwidth limits).

 

[gigatexal]

I had that inkling as well. I hate comcast. To get to Comcast senior biz tech support I had to threaten to recommend my client move to frontier FIOS.

 

[compuwizz]

If they don't have a static IP, I'd suggest bringing your own modem and going with a Arris SB8200. Yes it is more expensive but if a 3.1 Docsis channel is available, I've found it to be more stable and lower jitter than 3.0 channels.

 

[Blinky 42]

Do they use Comcast for phone also or just internet?
You can call up the biz support people and have them turn off the xfinity wifi in the modem, it is on by default.

 

[nitrobass24]

I am not following your post. TBH I feel like @gigatexal is trolling us that said I am calling BS on all of this.

ultimately, that sounds like a super janky setup and I would def recommend some basic changes like their own UTM & AP.

 

[MiniKnight]

Don't use Comcast AIO

 

[fractal]

Do you have an android phone? If so, wifianalyzer is your friend. Cheap site survey to tell if you stand a chance.

Next, where is the AOI located? On top of the microwave? Just joking. WiFi is like food service. It is location, location and location.

Yeah, one guy can take all the bandwidth ... or more importantly ... air time. Get some crappy device that insists on running at the lowest rate and you will eat all your airtime doing nothing. Enterprise gear has the ability to tell those devices to take a hike.

Yeah, there is an arbitrary limit to the number of connections. But what you are describing sounds more like channel capacity or air time.

TBH, it sounds like you want to sell him stuff without figuring out what the problem is.

Me? I think it is the x-ray machine...

 

[gigatexal]

The modem is on top of the fridge. No microwave in sight.

I am not trying to just upsell my client just to lock them into my services. I am trying to get them to a more standard setup that anyone here could triage if need be. I hate the idea of an all in one unit. I like hardware that does one thing and one thing well.

With a pfsense box they would get much better security, WAN speedups from the likes of squid, etc.

It very much could have been a busy channel -- I will look into that.

 

[vl1969]

well you do not actually need to use comcast unit for everything.
get a separate wifi router,
build out pfsense machine.

than go into comcast unit and disable all the function except modem.
you should be able to disable the wifi all together.
and DHCP /DNS . there maybe even an Access Point mode that makes it modem only.
than connect and configure your pfSense to be the primary gateway.
than connect the wifi unit and set it up as AP only pointing to pfSense as gateway and DNS.

at best, your pfSense will get the WAN ip as it should
at worst you will have to leave the comcast as is sance wifi and connect only pfSense to it.

 

[tullnd]

Any chance one of the devices is an old 802.11G device? That can kill wireless N speeds sometimes.

Methodically, I'd kill all wifi devices, have people turn them on one at a time. Start with newest devices and test. See if it continues to work until one of the older wireless phones/devices is enabled and suddenly identifies a culprit.

The other option is to just take a half-way decent SOHO wireless router(R7000, anything like that, not great, but better than what Comcast provides) and set it up as just an AP at first, connecting everything to that wifi. Disable the built-in wifi on the Comcast if you can, but even with interference, you may get better performance, enough to indicate the Comcast equipment is the issue. Frankly, it's likely the wifi that's the cause or one of the client devices.

I can tell you, working for an ISP, we've had scenarios where the gateway devices we supply, sometimes have had issues with certain older wifi equipment in homes. Depending on the client device, we've identified some that were common enough to be worth pursueing a firmware update to fix(not cheap, tons of time/effort to develop, test and deploy, plus deployment risks which always results in some failures and then truck rolls when you update tens of thousands of devices a night). Sometimes if the client was really old, we just documented it and advised people of the compatibility problem of running a really old device like that.

 

[kendrick]

First question is the office using the xfinity guest service for their customers? if yes dont ditch the box just shut off the internal wifi and give them a real wifi router for the staff use. The refer is no better than a microwave depending on its age. adding the other 2 behind the comcast device is still a decent idea regardless. if they dont have static ip's and dont do xfinity, byod it will save them 10 or 20$ a month on fees.

I have cc business and dont have a aio device due to those kinds of issues. im stuck with rental since i have a static ipv4 for servers. once i get all my ipv6 stuff sorted out that my change. I got a brand new router from cc to do 100mb+ and couldent keep the static ip on it. ended up being a dud modem so that is also a posibility in this case as well.