Cablemodem frequent connection loss

Question

I have a Linksys BEFCMU10 cablemodem and a WRT54GL router with Tomato 1.27 firmware on Cox cable. My question is this: I get what seems to be random disconnects from the internet, where the cable modem lights are still normal, but I can connect nowhere, either via a url or an ip address. At the same time these disconnects are happening, I can go to the router's Tomato management webpage, and release/renew my external IP address from Cox's DHCP server. I've had Cox look at the signal levels on the cable modem, and they say they look fine. What brings back the modem, for sometimes as long as 17 days, is several power-cycles of the modem. I don't understand the underlying cable modem technology too well, but I do know that if I'm able to release/renew the DHCP-provided WAN address, I'd expect that the cable modem was working ok... Anybody have any ideas??

Answer 1

Cable modems work on a network/grid that connects to a T3 router running at 45 Megabits per second. Each area is a grid and this grid only has so many slots available. Depending on where you live, you could have a busy grid, or a not-so-busy one. My grid for example, was very busy; so I didnt get very good performance and I had the same problems as you. (ie.. when the slots in the grid are full, a cycle is required which should put you back with the active users. The problem lies with the cable companies' lack of upgrades to their equipment to meet the needs of the consumer. There isn't much you can do besides maybe write angry letters or switch to DSL which has slower speeds.

Answer 2

I had a similar problem to this with my cable connection. For me it turned out to be I was not getting a good signal to the cable modem. My internet would work for several days, but would just drop out every once in a while unexpectedly.

Do you have any splitters on the coax between the line into your house and the cable modem? If so, try to remove them(or at least all but 1 if you use your cable for TV as well) and see if you see any difference.

Answer 3

@DataPimp is right. If your physical connection to Cox is sound and you can renew your IP whenever you want, then the connection from your house to Cox is fine and so is your modem. What's happening is probably that Cox has oversold their capacity in your area.

I would wager that your issues happen most frequently during the same times of day that everyone else in your neighborhood is online: weekday evenings, during bad weather, and during big sports/news events? You would probably notice killer throughput in the middle of the night, or on gorgeous days when everyone's outside.