5 ms·

My area (Astoria, Queens) recently got upgraded to 300/20mbps but, to get that speed, I needed to upgrade my modem. I wouldn't be surprised if this new modem wi

My area (Astoria, Queens) recently got upgraded to 300/20mbps but, to get that speed, I needed to upgrade my modem. I wouldn't be surprised if this new modem will have this capability. It's yet another reason to have your own router behind their modem. As long as my speed doesn't degrade and I'm using my own router behind the modem, I don't mind if they make it a public hot spot. Of course, most people use the cable companies modem as their wifi/router. I wouldn't be surprised if people discover major security vulnerabilities in these mix-public/private modems.

learc83 12y ago
>As long as my speed doesn't degrade and I'm using my own router behind the modem, I don't mind if they make it a public hot spot. If your wireless router is near the modem and it's broadcasting on an overlapping channel then it will definitely degrade your speed.
- MichaelApproved 12y ago
  How near is near?
- jrockway 12y ago
  First, if you care about wireless speed, you're not using 2.4GHz, you're using 5GHz. 5GHz channels do not overlap. Second, other WiFi networks are not really the cause of interference. Certainly, if two networks are sharing the same channel and both have stations that want to use the full bandwidth at the same time, that won't work. But WiFi does listen before it transmits, and does not transmit when it can hear other stations transmitting. This lets many networks share the same channel. Where this goes wrong is when two stations want to talk to the same access point, but can't hear each other. (The "hidden node" problem.) In that case, station A can't tell that station B is transmitting, and so station A might transmit over station B's transmission, resulting in garbage at the access point. (Access points that can both hear a station but not each other can also do this, of course.) In the scenario you mention, your own access point and Comcast's access point are almost in the same place, so they should be able to hear the same set of stations. If they pick the same channel (and autoselection _is_ notoriously poor), they should not interfere except to share bandwidth. Finally, there's so much crap in the 2.4GHz band already that another WiFi network isn't going to make a difference. From my apartment I can hear 20+ WiFi networks, and if I look at a spectrum readout, can see tons of other things that I have no idea what they are. https://plus.google.com/115192122236060613729/posts/RZHLmV5KPQH https://plus.google.com/115192122236060613729/posts/RZHLmV5K...
  - learc83 12y ago
    >you're not using 2.4GHz, you're using 5GHz. I was assuming these comcast modems were 2.4GHz. But you have a point, if you're using a 5GHz router this problem is avoided. >Finally, there's so much crap in the 2.4GHz band already that another WiFi network isn't going to make a difference. From my apartment I can hear 20+ WiFi networks, and if I look at a spectrum readout, can see tons of other things that I have no idea what they are. That depends on where you live. At my house there are only 2 wireless networks near enough to matter and I moved my network to a non-overlapping channel. Also I use 2.4GHZ because 5GHz doesn't cover my entire house.
yeukhon 12y ago
> It's yet another reason to have your own router behind their modem. You sure? If you are connecting a CAT5 between the modem and a router, you are still using the modem. Are you sure you can stop the modem from acting on its own? My understanding is that you should instead replace the modem with your own, not just the router.
- jsz0 12y ago
  All cable modems (customer owned or ISP owned) are configured by the ISP. The main reason to buy your own modem is to save money by avoiding rental/lease charges from your ISP.

learc83 12y ago

>As long as my speed doesn't degrade and I'm using my own router behind the modem, I don't mind if they make it a public hot spot. If your wireless router is near the modem and it's broadcasting on an overlapping channel then it will definitely degrade your speed.

MichaelApproved 12y ago
How near is near?
jrockway 12y ago
First, if you care about wireless speed, you're not using 2.4GHz, you're using 5GHz. 5GHz channels do not overlap. Second, other WiFi networks are not really the cause of interference. Certainly, if two networks are sharing the same channel and both have stations that want to use the full bandwidth at the same time, that won't work. But WiFi does listen before it transmits, and does not transmit when it can hear other stations transmitting. This lets many networks share the same channel. Where this goes wrong is when two stations want to talk to the same access point, but can't hear each other. (The "hidden node" problem.) In that case, station A can't tell that station B is transmitting, and so station A might transmit over station B's transmission, resulting in garbage at the access point. (Access points that can both hear a station but not each other can also do this, of course.) In the scenario you mention, your own access point and Comcast's access point are almost in the same place, so they should be able to hear the same set of stations. If they pick the same channel (and autoselection _is_ notoriously poor), they should not interfere except to share bandwidth. Finally, there's so much crap in the 2.4GHz band already that another WiFi network isn't going to make a difference. From my apartment I can hear 20+ WiFi networks, and if I look at a spectrum readout, can see tons of other things that I have no idea what they are. https://plus.google.com/115192122236060613729/posts/RZHLmV5KPQH https://plus.google.com/115192122236060613729/posts/RZHLmV5K...
- learc83 12y ago
  >you're not using 2.4GHz, you're using 5GHz. I was assuming these comcast modems were 2.4GHz. But you have a point, if you're using a 5GHz router this problem is avoided. >Finally, there's so much crap in the 2.4GHz band already that another WiFi network isn't going to make a difference. From my apartment I can hear 20+ WiFi networks, and if I look at a spectrum readout, can see tons of other things that I have no idea what they are. That depends on where you live. At my house there are only 2 wireless networks near enough to matter and I moved my network to a non-overlapping channel. Also I use 2.4GHZ because 5GHz doesn't cover my entire house.

yeukhon 12y ago

> It's yet another reason to have your own router behind their modem. You sure? If you are connecting a CAT5 between the modem and a router, you are still using the modem. Are you sure you can stop the modem from acting on its own? My understanding is that you should instead replace the modem with your own, not just the router.

jsz0 12y ago
All cable modems (customer owned or ISP owned) are configured by the ISP. The main reason to buy your own modem is to save money by avoiding rental/lease charges from your ISP.