Need details of Comcast “xfinitywifi” public wi-fi hotspot I’m hosting

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Installed new Comcast Cisco Modem Model # DPC3939B

Noticed a new SSID: “xfinitywifi”
Comcast Support says this is coming from the modem
for Comcast customers to use.

—————————————————
Is there a separate radio in the modem for this?
What protocol is the xfinitywifi using? 802.11n? ac? g?
What Ghz does it use? 2.4? 5.0?
What channel (s)?

What control do I have?
Turn off xFinityWi-Fi only?
Turn off 5Ghz only?
Turn off all Wi-Fi on the modem?

If I attach another AP, will the xFininty Wi-Fi show up on it?

Thanks,

Who is John Galt?

Microsoft Surface Pro 3 with Windows 10, MS Office. Samsung Galaxy S9+ with Android 10.

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My ISP has the same system and I need to logon to their web site to opt out. The router has no controls for the public wifi.

cheers, Paul

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XFINITY WiFi Home Hotspots Frequently Asked Questions

XFINITY WiFi: Enable or Disable Home Hotspot in My Account

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Great question by the OP. Great answers by the WSF. What’s the matter Paul, don’t you want to share your bandwidth and Internet connection?

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I haven’t disabled it, just said that was how it’s done.

cheers, Paul

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Interesting……..never seen that before.

A quote from that first link:
====================
Will this impact the speeds I get at home? Will my Internet slow down when someone connects to my XFINITY WiFi network?
The broadband connection to the home will be unaffected by the XFINITY WiFi feature. Your in-home WiFi network, as well as XFINITY WiFi, use shared spectrum, and as with any shared medium there can be some impact as more devices share WiFi. We have provisioned the XFINITY WiFi feature to support robust usage, and therefore we anticipate minimal to no impact to the in-home WiFi network.
====================

They seem to contradict themselves in the one answer!

This sounds like a decisive statement:
The broadband connection to the home will be unaffected by the XFINITY WiFi feature.

…but then they end with:
we anticipate minimal to no impact to the in-home WiFi network.

That would _NOT_ fill me with confidence….just saying….

-brino

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They seem to contradict themselves in the one answer!

This sounds like a decisive statement:
The broadband connection to the home will be unaffected by the XFINITY WiFi feature.

…but then they end with:
we anticipate minimal to no impact to the in-home WiFi network

That’s not really a contradiction, because the first is talking about the cable connection and the second refers to potential antenna interference.

I’m more annoyed that Comcast expect to use my electricity to expand their network, even if it’s only likely to amount to pennies per year.

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thank you

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This sounds like a decisive statement:
The broadband connection to the home will be unaffected by the XFINITY WiFi feature.

…but then they end with:
we anticipate minimal to no impact to the in-home WiFi network.

That would _NOT_ fill me with confidence….just saying….

-brino

The Xfiniti SSID is configured as a Virtual network (VLAN), on a different subnet than your home LAN. Your network can’t see the devices or data on the VLAN nor can the devices on the VLAN see the devices or data on your home LAN. This lets Comcast still allow you to use the full broadband speed that you are paying for, while also allowing the Xfininty network to transfer data. How? The connection to your house is capable of far higher speeds than most people are paying for. Comcast artificially limits the speeds to and from your LAN via the modem, so that they can charge higher rates for faster speeds (yet they still cap the amount of data per month at nearly the same amount in some markets! ). So you can be down/uploading at whatever speed you pay for, while the modem can also be down/uploading on the Xfinitiy VLAN at the same time by using the “extra” capability of the network connection to your house. The data moving across is the Xfinity VLAN supposedly does not count towards your monthly data usage.

So, Comcast can prevent a loss of speed, but only on the WAN side of the network. What they allude to, but don’t fully answer in their FAQ, is what happens on the wireless LAN side of the modem/router. The wireless radio in the modem is shared by all of the devices, regardless of which LAN or VLAN the devices are a part of. So, if you are trying to move a lot of data (to/from the internet, OR just to/from another computer within your LAN) your wireless radio will share its total bandwidth between your devices and any devices connected to the Xfinity VLAN.

Now for the good news. I suspect that not many people ever even connect to the Xfinity SSID. It requires that you be a Comcast subscriber and you must login with your Comcast user ID and password. I don’t see how that would be useful to most people in a typical neighborhood. If I’m at home, already using the 50 Mbps Comcast connection that I pay for, then why would I need to use the Xfinity SSID? I suppose it might be useful for someone that needs to travel with a laptop. Real estate agents could make use of it to keep their mobile data costs reasonable, perhaps logging in to their laptops to look up a property while sitting in a Comcast-served neighborhood (if they also are a Comcast subscriber). Maybe if you live near a park where people hang out with their laptops, then it would be nice for them to use. Otherwise, it just seems like a marketing gimmick.

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Now for the good news. I suspect that not many people ever even connect to the Xfinity SSID. It requires that you be a Comcast subscriber and you must login with your Comcast user ID and password. I don’t see how that would be useful to most people in a typical neighborhood. If I’m at home, already using the 50 Mbps Comcast connection that I pay for, then why would I need to use the Xfinity SSID? I suppose it might be useful for someone that needs to travel with a laptop. Real estate agents could make use of it to keep their mobile data costs reasonable, perhaps logging in to their laptops to look up a property while sitting in a Comcast-served neighborhood (if they also are a Comcast subscriber). Maybe if you live near a park where people hang out with their laptops, then it would be nice for them to use. Otherwise, it just seems like a marketing gimmick.

I agree that usage will be limited. If someone is checking their email, virtually nothing. Even that hypothetical real estate agent would be brief and probably unlikely. They need reliable data connections for their work. They can’t chance relying on finding an xfinity shared hotspot.

This is a very common system in Europe, though typically used in a different way. The public wifi channel is meant for cell phone users, not computers. It’s for those of us with no data plans or limited data. It dramatically increases the number of locations where we can get wifi.

In France my cell phone provider is Free.fr. I pay $2.20/month (no typo) for 120 minutes of local and international outgoing calls. (Extra minutes are very cheap.) Receiving calls or accessing voice mail doesn’t use minutes. I also get a token amount of data.

I also get free wifi access to the public channel of all Free.fr internet routers throughout France. The SIM card from Free.fr makes the connection encrypted (like a VPN) and does the login. I can’t imagine I make a noticeable blip in the usage of any one shared router. I don’t stream movies on my phone, or at least not standing out in front of someone’s home or apartment building where I might be checking my email or a map.

It sounds like xfinity’s system would work similarly but it’s tied to your internet provider (xfinity) and not to your cell phone provider. Since I’m not in an xfinity-served area, I couldn’t use it.

I should add that the European systems only work with cell phones that have compatible circuitry and software. All iphones do. Android phones typically have the circuitry but the Android operating system hadn’t implemented EAP-SIM (Extensible Authentication Protocol) last time I checked.

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I use the ISP public wireless on other people’s routers all the time and find it very useful – in the middle of a graveyard the other day – so I’m happy to pay for the electricity and possible bandwidth impact.

cheers, Paul

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AFAIK, this is part of their drive to have Xfinity WiFi available everywhere. In theory, if you have Xfinity internet service, you could go anywhere there is a Xfinity internet router and have access to the internet.

That’s all well and good for Comcast, but as far as I am concerned, it’s like the electric company putting an outlet at the curb outside my house and inviting everyone to drive up use it as they please. I’m sorry, but if you want to allow public access to something that I am paying for, then I want a credit to appear on my bill for that.

It really doesn’t hurt me that it’s there and it’s not hard to turn off (if you know how) but the sheer arrogance of it all really ticks me off. And it’s not like Comcast has been upfront about this and let people know about it. Reminds me of the plans to knock Arthur Dent’s* house down that are “on public display in the planning office” as long as you consider locked in a basement closet behind a filing cabinet “public”.

*”Hitchhikers Guide to the Galaxy”, if you must ask.

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If you are feeling altruistic enough to share your wireless bandwith with in-range users (e.g. traveling salesmen, google streets trucks, the kids next door circumventing parental controls, folks who can’t afford internet service), I might suggest checking out:
https://openwireless.org/

Of course if you don’t mind donating it to your ISP to use as they see fit, it appears Comcast opts you in automatically.

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Reminds me of the plans to knock Arthur Dent’s* house down that are “on public display in the planning office” as long as you consider locked in a basement closet behind a filing cabinet “public”.

*”Hitchhikers Guide to the Galaxy”, if you must ask.

Yes the Vogons ARE coming but remember Don’t Panic and bring your towel ….

Just because you don't know where you are going doesn't mean any road will get you there.

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I turned mine off the day I had to switched to their gateway device TG862G

when someone comes over and needs to use wireless I log them on… this is far and few between as kids are grown and have moved out. while my speeds are great I prefer to keep them for my self http://results.speedtest.comcast.net/result/934846224.png

as for wireless my late 2013 rMBP 15″ gets between 63-65Mpbs

having 2 iPhones, 2 iPads my retina MacBook Pro my wife’s work laptop and my Windows desktop going I feel that’s all I am putting on my network. When I am out and about I rarely need wifi on my phones as we get LTE speeds just about anywhere in our area.

looking at the Comcast forums regarding this it seems more opt out than in. but of course this is just a sampling of people that post. most don’t even know they are carrying the wifi.

my 2 cents

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What’s the issue, it doesn’t cost you anything and you can use the service when you are out and about?

cheers, Paul

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If you have any concerns at all, I would first recommend that you operate your own WiFi-capable router, and disable the radio in Comcast modem. You may need to ask Comcast to “bridge” their device, as you do not want to be double NAT-ed, assuming the Comcast device acts as a router.

Finally, I would remove the antenna from the Comcast device.

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By the way, in case anyone was wondering about bandwidth usage and caps, using someone else’s XFinity WiFi hotspot counts against the user’s own Comcast Account. Not the host network’s usage cap. So, using someone else’s WiFi in this system will not allow you to exceed your own account’s bandwidth usage cap. And letting someone use your public WiFi will not count against your usage cap.

No official work from Comcast about how usage caps are to be applied to public-facing XFinity WiFi, but this scenario seems reasonable to conclude based on an ongoing discussion thread at dsl reports. After all, you do log in with your own Comcast account info.

You are also not going to be held liable for anyone’s illegal use of your public WiFi, as long as it stays outside your own in-home network. That’s directly from Comcast’s own FAQs about this service.

-- rc primak

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I purchased my own Comcast-approved device, an Arris TM722G/CT (https://www.google.com/#newwindow=1&q=Arris+TM722G%2FCT), at a Comcast outlet located within a local Best Buy store, so that I would not have to pay their monthly rental fee for their device. This device supports the DOCCIS 3.0 standard (https://en.wikipedia.org/wiki/DOCSIS). While it is a modem only, I have a separate router that supports the newest wireless standard, 802.11ac.

The Comcast supplied devices, which include a modem + router in one device, only provide wireless service in the 2.4 GHz bandwidth. If your equipment was purchased after 2009, it most likely provides support for the much less crowded 5.0 GHz spectrum.

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