Combining two ethernet ports

Question

My computer has two gigabit ethernet ports on the motherboard. Is it possible to have the OS (Win XP) combine them and treat as a single 2-gigabit connection? Failing that, is there any general advantage to just have both plugged in to my switch with two separate IP addresses?

Answer 1

Link Aggregation is the term that you're looking for, but in most home setups this is not possible. You need a switch that supports 802.3ad, and those are usually semi-expensive enterprise-class pieces of equipment. Assuming you have such hardware, you need a NIC that supports it as well.

Other terms for Link Aggregation include: NIC Teaming, Etherchannel, Port Channel, or trunking.

edit: To answer your last question, if you're on a standard home router and that is your only piece of networking equipment then there probably isn't much to gain from having 2 links.

Answer 2

Windows XP doesn't natively support this but there are some motherboards that have link-aggregation capability, like Nvidia's Dualnet. Of course it's hardware specific and requires appropriate drivers. Here's one motherboard that has it: http://hothardware.com/articles/NVIDIA-nForce-680i-SLI-Preview/?page=3

There is this fellow who achieved a noteworthy increase in read/write speed,

Performance from the same workstation to the TS509 (neither teamed) was previously 45MB/s write, and about 60MB/s read. With the same workstation now configured with two gigabit LAN connections, the TS509 connected in the same manner, and the LACL trunks set up, I got a surprise. Write speeds jumped to 50MB/s and read speads are much higher at 83 MB/s using our 5.3GB test set of files.

but as MarkM says, it's not your normal home hardware.

Answer 3

No, there is not. Ethernet is a broadcast medium, so even if you could do this, both ports can't 'speak' at the same time. Furthermore, the routing for making this work would be complex and prone to failure.

Looks like I'm wrong, see below!

You could have two separate networks attached to your machine. So if you had two switches on two different networks, you could hook up one port to each switch. The primary use for a situation like this would be if you wanted to have one port be used for your external network traffic, and one port for purely local LAN-based traffic. But that's not really what you're trying to do. You want to use two ports to get a performance boost while speaking to a single external network, and that isn't going to work.

Answer 4

Mostly this has been answered, however, you've still got 2 ports, you could always use the second port to connect to a device that you use a lot over a dedicated cross-over cable - perhaps a NAS. I'm fairly certain that a short direct cable will be faster than even the best switch/router

Answer 5

micmcg is correct - these are the few reasons I can think of why a home user would want link aggregation:

1. Each computer is link aggregated and is going to access a central point at once
2. One computer is going to another with a RAID setup that allows transfer at the link aggregation speed (you are using RAID to go BEYOND normal gigabit speed)
3. Multiple computers to one computer, definitely makes sense
4. Most people don't understand saturation and bandwidth, hence why micmcg is stirring the pot