Question About Cable Modems

[andrewfee]

does any one know if my connection is significantly slower when connecting my cable modem to my hub, and then into one NIC, or if it is faster to have the modem going into a NIC of its own. I have noticed that when i moved it over it causes a lot of packet collisions, but still downloads at 80-60k/sec (512k connection)

the reason for this is that with one NIC my pc boots normally, but with two, it takes another 20 seconds or so before i can do anything, and the system seems to perform worse in general.

[brc64]

What exactly are you plugged into? Is it a hub, a switch, or a router?

- Me

[andrewfee]

sorry, its an Asanté 8-Port Ethernet Hub

[camrymans]

shouldn't matter

Most cable modems don't exceed 3Mbit/sec, so a 10Mbit hub should be able to handle it without any problems. All hubs will get collisions because they are half-duplex devices (meaning only one device can transmit at any time, and in one direction). I used to use 3 computers and a 10Mbit hub without a problem. I am currently running a Linksys router connected to a D-Link 5-port 10/100Mbit switch and then to three computers. Now I can run 100Mbit Full-Duplex for all devices.

[andrewfee]

thanks, but i cant seem to get my other computer to see the connection when the modem is connected to the hub, so it looks like i'll have to go back to using two nics and losing a fair bit of performance

[brc64]

I'm a bit of a novice in networking, but I was under the impression that a hub or switch would not work when it came to sharing an internet connection, unless one of the computers had two NICs (which is what you are trying to avoid). That's what a router is for. The cable modem plugs into the router, and you configure the router (through some sort of included software or configuration utilities) with all of the settings you'd have to use if the cable modem were connected directly to a computer. The problem with using a hub or switch is that the device doesn't "hold" the configuration info for the modem, so it doesn't actually share the connection.

The best analogy I can think of is cable TV. Let's say you've got cable, and you use a cable box to get premium channels. Now, you can use a splitter (the hub, in this case) to split the cable coming from the wall so that you can run it to another TV (computer), but since you've only got one cable box (I suppose IP address would be the best fit for this analogy), you can only get premium channels on one of the TVs.

A router would be kind of like a cable box that had multiple outputs, and also allowed each TV to watch something different. When you use two different NICs, it's like you're creating a virtual router. Your computer becomes the special cable box.

Does that make any sense?

- Me

[andrewfee]

makes perfect sense, anyone know how much a router is ?

[brc64]

They generally run from $100-200. We just bought one not too long ago here. $72 with a $20 rebate. It's been up and running for nearly two weeks now and we haven't had any problems.

- Me

[Clockwork]

That information simply is not true at all. A hub will work just fine. Only 2 nics are needed if the provider allows multiple connections/IP addresses (my provider allows 4). If not you need an extra nic and NAT or proxy software.

Check out the details HERE!

A router is a viable option (although can be expensive) if htere is no other choice. Please don't hand out information you are not sure on. Especially if this ends up costing the person more than it needs to..ahem

[camrymans]

ok

I think we are all assuming he is only getting 1 IP address from his ISP. In that case, he either needs a router or will just have to use the machine with two nic cards. If he can get a 2nd IP address, I would just recommend he use a hub.

[brc64]

Originally posted by Clockwork
That information simply is not true at all. A hub will work just fine. Only 2 nics are needed if the provider allows multiple connections/IP addresses (my provider allows 4). If not you need an extra nic and NAT or proxy software.

Check out the details HERE!

A router is a viable option (although can be expensive) if htere is no other choice. Please don't hand out information you are not sure on. Especially if this ends up costing the person more than it needs to..ahem

Hey, calm down man.. I started off my post saying that I'm a novice when it comes to networking, and then simply went on to say what I've learned with my dealings with cable modems and internet connection sharing. I had never heard of cable providers allowing more than one IP address (without costing more money), and if his service allows only a single IP, then I believe my advice is valid.

After looking over the webpage you provided, it looks as if the ONLY way using a hub will work is if his service does indeed allow multiple IPs. The only other option involved using two NICs and setting up a computer as a gateway. If you read his initial post, you'd see that he was trying to avoid the 2 NIC solution, which is why I didn't mention it.

- Me