My computer used to act as a router, making two network cards a neccesity. After so many problems with that, I just decided to get a router. Now I have two network cards plugged into my computer, and have plugged both into the router for the hell of it. But I’m wondering if there is any real benefit of doing this? Could the computer take advantage of it and do some sort of threading if I have more than one thing downloading at a time? (I’m using WinXP Pro)
I don’t know, but it wouldn’t matter for downloading. A great cable connection might be 5Mbps down, and a network card’s slowest speed is 10Mbps (most of them are 100 these days, and some are 1000)
Now, it might be faster for transfering files between computers, but if your other computers only have one network card, it wouldn’t matter. Well, unless you’re in the habit of transfering files from multiple computers at the same time.
I figured the cable connection probably was smaller than my network connection, but I think I’ll leave it like it is for now. Maybe it will come in handy if I’m downloading and transfering files to/fro my mom’s computer.
This setup is not going to provide you with any benefit. And, while unlikely, it’s possible that this setup could lead to problems. I’d recommend disconnecting and deactivating one of the cards.
The only way you could derive any benefit from this setup when transferring files to/from your mom’s computer is to isolate that node and the internet connection on their own NIC. In other words, basically the same topology you had before. And, I bet you’d be hard-pressed to detect any speed benefit, and it’s probably be a bigger headache than it’s worth.
There is absolutely no advantage to doing this in your configuration, and in fact it might cause problems.
It is possible to use two (or more) adapters in parallel to multiply effective bandwidth. This is variously called “adapter teaming”, “adapter channeling”, or “EtherChanneling” (Cisco’s term). Doing this requires special software on the host computer and usually configuration changes on the device at the other end.
However, in your case, you presumably have a 100 Mb/s internal network connected via a router to either a DSL line or a cable modem connection, at somewhere between 384 and 2048 kb/s. The communications bottleneck here is the DSL line or CM connection (hereinafter, “broadband service connection”). You wouldn’t possibly gain any performance benefit because all the data has to go through the single broadband service connection anyway; your internal LAN is at least 50 times faster than the bottleneck, and freeing up that bottleneck won’t improve performance one bit.
If you do a great deal of internal data transfer between computers on your local area network and if you have a sufficiently intelligent network infrastructure and if you install teaming software on your host computer, then you might see some benefit. But you won’t when downloading over a broadband connection.
On the assumption that you have not installed teaming software, what ends up happening is your router assigns a second, distinct private IP address to the second interface on your computer. Your computer now has the choice of two different IP addresses to use to talk to the rest of the network. This doesn’t give you any advantage because the router is going to translate both internal addresses back to the same external address on the way out. Internally it could cause problems with some networking protocols (specifically, Windows File and Print Sharing), although I would expect nothing much to come of it. I’ve run my laptop with two adapters connected to the same network for extended periods of time (during wireless testing) without any serious ill consequences.
There probably isn’t much benefit in using both cards facing the LAN, but you could set up a network bridge - this extends the network through your machine and out of the other card (effectively making your PC into a mini-switch/router), but even then, I can’t think of any particularly compelling reason to do so; even if you were short of network sockets in your part of the building, 8 port ethernet switches are dirt cheap now and would be a better solution because all the ports would work even with your machine turned off.
Couldn’t he set up the 2 network cards, with the correct software, as a load-balancing team so that if one card fails the other will take the traffic without loss of service?
but that’s if you really don’t want to remove one of the cards. Otherwise as already mentioned, it’ll be easier in the long-run to remove one of the cards.
I’ve never actually experienced a hardware failure on a NIC - I’m not saying it can’t happen, but it doesn’t seem like all that big a probability; what I have experienced is NIC driver problems, which would probably affect both cards if it affected one.
On a sort of related note; is it just me or are network cards getting smaller? - I bought one the other day and it has about three components on the PCB (two of which are tiny SM diodes or resistors) - what happened to all the capacitors and stuff?
Yes, you can do that, with special software. It’s not load-balancing in that case, though; that’s a hot spare.
Card failure is unusual, but not unheard of. Cable failure is actually more likely in most environments – especially if you have builders in the building. Or rodents.
ahh, hot-spare…I didn’t know what the term was in English 
All my servers at work have 2 NIC’s in hot spare mode but as Mangetout pointed out a hardware problem is rare. Though some of the machines are connected to a LAN and a WAN at the same time, each card with a different IP.
So if xgxlx wanted to create a LAN at home would he need 2 NIC’s connected?