To the Editor:
I'm writing in regards to the April 3 article by Nathaniel Ward, "Network upgrade in final stages," in order to clear up some common misconceptions in the article.
Because everything stored in the computer is represented by zeros and ones (also called bits), the system of numbering for data storage is based on powers of two, and not the more human-readable decimal system. Also, there is a difference between a bit (a single zero or one) and a byte (which is made up of a string of eight bits). So therefore one GB is equal to 1024 MB and 1 MB is equaled to 1024 KB.
And this is where it gets confusing. When we talk about network bandwidth, the measurement unit is in bits per second, however the system of number used here, instead, is the decimal system. So therefore we would say Gbps for "Gigabits per second", which is equal to 1000 Mbps (Megabits per second), etc. The conventional ways of writing it is that an uppercase B equals a byte, and lowercase b equals a bit.
So how does network bandwidth translate to how many files you can actually transfer across the network? Say the network is the newly upgraded Dartmouth network, and it is rated as a Gigabit Ethernet (bandwidth is 1 Gbps), or 1,000,000,000 bits per second. We have to divide this number by eight to find out how many bytes per second (remember eight bits are one byte). So a Gigabit Ethernet is actually 125,000,000 B/s. Divide this number by 1024 (one KB equals 1024 B), and we get about 122,070 KB/s, which is just under 120 MB/s. This is very different from the 1000 MB/s that the article states. 120 MBs is about 25 MP3 songs.
Of course, as stated in the article, this number is purely the theoretical limit of network bandwidth. The actual file download speed of a typical end-user will probably be nowhere near the theoretical limit due to bottlenecks on the computer itself. Applications like streaming video, on the other hand, that don't write onto the hard drive would see more use of the increased bandwidth (there is a streaming video software developed in Japan that can take up to 30 Mbps for just a single video stream).
The change from a 100 Mbps to a one Gbps network backbone (copper wire to fiber-optic) will benefit the user. For example, if 20 users are streaming video over the same line at 5 Mbps each, then the link is saturated and may result in unreliable connection. Now that the capacity of the link has been increased 10 times, not only will the link be more reliable (right now only 10 percent saturated), it can take on 180 more concurrent streaming video users (or each of the 20 existing users will now be able to download at 50 Mbps each!). That's where the improvements will show.
