How fast is FastLynx TCP/IP ?

Someone recently asked how fast FastLynx can transfer data using a gigabit ethernet card. Well, there are a few important factors that affect transfer speeds.

First, fast ethernet (what most cards use these days) runs at 100 Mbps (megabits per second). Gigabit ethernet runs at 1 Gbps (gigabits per second) which is roughly equivalent to 1000 Mbps–100 times faster than fast ethernet. So theoretically, transfers could be 100 times faster than with the average ethernet card.

NOTE: the terms megabits and gigabits are slightly misleading. For those who don’t know, there is a difference between megabits and megabytes. A byte is made up of 8 bits. We usually use the term byte or megabyte when referring to file sizes or memory capacity. However, when talking about bandwidth or network transmission capacity, we use bits–don’t ask why, it’s just tradition. The point is that a 100 Mbps ethernet card has the ability to transfer about 12.5 megabytes (MB) of data through itself every second. A Gigabit card has the ability to transfer 125 MB of data through itself every second.

Secondly, transfer speeds are only as fast as the slowest link. For example, if one computer has a 100 Mbps card and the second has a 1000 Mbps card, then the transfer will be limited by the top speed of the slower computer, i.e., 100 Mbps.

Thirdly, network congestion can also slowdown a transfer. If you are sharing the network with other users, e.g., game playing teenagers, it’s not unlikely that their network traffic can cause congestion on the network. This basically means that the routers that shuffle your data in and out of your network have to divide their time between your data and the gamers’ data.

Fourthly, propagation delay can sometimes slowdown a transfer. If you are transferring files to a computer in China, your data has to travel many thousands of miles to reach its destination. I know it’s surprising, but in such cases, even though your data is traveling at nearly the speed of light, you will often experience a noticable delay due to the sheer distance that your data is traveling. The horrible truth about this slowdown factor is that we can’t do anything about it–you can’t increase the speed of light. So much for realtime video conferencing with aliens on Mars.

Fifthly, network errors can cause slowdowns. This is termed as “dropping packets”. In today’s wired networks, this problem has been minimalized. However, in wireless networks, all sorts of interference can cause packets to be dropped, necessitating retransmission which slows down the overall transfer rate. Whether it be from two many laptops trying to use the same wireless access point or your neighbor’s microwave oven flooding the air with interference, network errors can significantly decrease transfer speeds.

Finally, your computer’s processing speed can play a big role. I said earlier that a gigabit card has the ability to transfer at 1000 Mbps. However, if your computer is bogged down with 5 Internet Explorer windows, 2 Word documents, Outlook, Norton Anti-virus, iTunes, and a game of Solitaire, then your computer probably won’t be able to shove enough data down to the gigabit ethernet card to use its full capacity.

So, when you’re transferring your files with FastLynx, and you want it to go faster, try tweaking a few of these parameters. Oh, and let me know if you find a way to increase the speed of light. You and I could make a lot of money…