I was in no hurry to upgrade my home network from 100 Mb/s to gigabit speed, which is odd when you consider how much time I spend waiting for file transfers. That's because when I spend money on PC upgrades, I think of the components that offer an immediate performance increase in the applications and games that I run. Putting cash towards things like video cards, CPUs, and even peripherals is almost like buying toys for myself. For some reason, network components don’t inspire the same amount of excitement. Indeed, it’s harder to let go of hard-earned money when it feels like an infrastructure investment rather than a self-gifted advance birthday present.
Inevitably, however, my high-bandwidth networking demands were making it obvious that 100 Mb/s weren’t going to cut it anymore if I valued my time. All of the systems I was running at home already had gigabit network controllers built into their motherboards, and I remember looking into the rest of the hardware shopping list that I needed to step up my network to full gigabit speed.
When I was all done collecting the pieces, I remember copying a large file over the old 100 megabit equipment, which took about a minute and a half, and then upgrading to the gigabit network. After the upgrade, it took about 40 seconds to copy the same file. It was a nice performance boost, but not quite the 10 times difference between 100 Mb/s and 1 Gb/s I was expecting.
What's with that, anyway?
If you’ve had a similar experience, or you plan on migrating to a gigabit network yourself, read on. We’ll be going over the basics of gigabit networking, the variables that will impact the network speed, and what you can do about them to get the most out of Gigabit Ethernet.
secondly if you have more than a point to point connection, (ie more than 2 devices) on the network your speeds will suffer.
Even if they are on seperate collision domains, you will still get broadcast trafic that will intrupt conversations.
And lastly the quility of you network cards! there is a reson that one network card will set you back £15 and another cost £150. I have found almost with out exception that a more expensive high quility card will sustain a higher through put than a cheap card.. you dont need to spend £150. but think twice before chosing a £10 card over a £25 one..
Now if you had the efficiency of Token Ring with the bandwidth of ethernet....wow!
My own computer runs off a 50ft. cable to the central hub.
First of all, the theoretical maximum transmit rate in one direction is not the same as how fast the file is copied. You have to consider, that a file copy will use TCP-IP protocol on the network. The Transmission Control Protocol splits the whole file to small pieces, usually of approx 1500 bytes long including the frame header, which needs to be acknowledged by the receiver. The sender and receiver operates with a window size, which is the number of unacknowledged packages. The sender sends a number of packages and then waits for an acknowledge signalling, that the receiver has received them all. If not, they need to be retransmitted. Then the sender can send the next portion of the file.
So the actual network card on both sides will be a very limitting factor. In theory you will be able to transfer (!) something between the half and 90% of the maximum rate in one direction.
But that is not the only limitting factor. The packages needs to be processed as well. The PC's will be interrupted for very package they receive and they need to get the data out of the network card in same speed as they arrive and put the data somewhere. For 125MB/sec and 1250-1400 bytes in one package, the PC needs to handle approx 100.000 requests/interrupts in a second from the network card and then probably the next 50.000 from the harddrive. It means 150.000 interrupts more, then required for normal functionality. It requires a lot of processing power from the hardware and from the operating system as well. Let me say, that windows will not be my choice of the operating system to handle this amount of data with very low latency.
The network speed measured in Gigabits is often more a sale trick then an actual information telling anything about the actual transfer speed. It is true, that when using higher speeds you will get the file over faster. However, you will be far from the maximum specification. If you want to utilize the full bandwidth, you need to invest into hardware, which is able to handle it. The majority of the systems, especially the notebooks, are able to send few packages with the right speed, but then they spend more time with waiting then with utilizing the full bandwith.
Another thing is the size of the package. The old ethernet uses 1500 bytes packages. It is a very limiting factor and I hope that in the future the ethernet specifications will be changed to support much larger packages. Today they are trying to use jumbo packages which are packages typ. up to 9kB. It is still to small for an effective data transfer on the network.
hum..... he did that...
I doubt it, most game servers need very little bandwidth really since not a great deal of information is needed to be transfered.
"Each 1000BASE-T network segment can be a maximum length of 100 meters (328 feet), and must utilize "Category 5" cabling at a minimum".
http://en.wikipedia.org/wiki/1000BASE-T#1000BASE-T
Now calculate the time spent for transmission of each ack packet set back through the network , there's the rest of the time and bytes which constitute remainder of 125Mb/s, the rest is in Amgsoft's post.
Well written indeed...
Anyone know if a Gigabit switch connected to a Fast Ethernet router will slow down much? The router is the HDCP server for the network.