Thank you for the modem information.
Your modem is a Technicolor TC8305C.
Is the gateway unit in BRIDGE MODE?
Bridge mode disables the wireless router function of the gateway so you can use your own router.
If you don't have it in bridge mode and are using the router that could be part of your problem. I can't recall if using both at the same time still allows internet access.
If you don't know if it is in bridge mode you can easily check.
Go to the gateway administration page here http://10.0.0.1/
and sign in.
•Default username (case sensitive): admin
•Default password (case sensitive): password
If you have changed the password use the one you set up.
On the first page of the admin tool you will see something related to bridge mode.
If you do have it set to bridge it will tell you.
If not, set it to bridge mode.
When I had to use my gateway for a few days in July due to my router going bad, I had a horrible experience with the gateway.
While the signal was good every where in the house, my speeds went down and were slower than a turtle.
A 30 second download took an hour.
Another one that should have taken less than a minute took all night and it still had not finished downloading by the next morning.
I got a new router a lot sooner than I had planned on getting it.
Each person has a different experience using the gateway unit. You will have to see what it does for you.
If you decide to use the gateway, unhook the router and put it aside.
Scroll down and click Save or whatever it says.
Unfortunately, I cannot tell you exactly what the page says because the admin page seems to be down at the moment for me. It may or may not be down for you.
After you set it to bridge mode, you might have to reconnect to the network you set up with your router.
If successful, see if the issues still occur or if they are resolved.
If not, it will be your router, which you can either replace or take the gateway out of bridge mode and use that for your wireless.
edit to add: if you don't know if the gateway is in bridge mode and the admin page is down and are feeling adventurous you can always unhook the router and see if you can connect to the internet using the gateway. You will need to know the default name of the gateway network and password to connect to it. This can be found on a sticker somewhere on the gateway. (if you do use it you can also change the network name and password from the long one supplied by Comcast without having to go to the admin site. I can tell how to do that if needed).
Edited by Queen-Evie, 11 September 2015 - 02:34 PM.
corrected month I had to use gateway