Bandwidth Concerns

My goal is to provide my customers with the fastest, most reliable internet service possible. In order to insure this, I must make sure that abuse of the system by a select few does not ruin it for the rest. For this reason I am shutting down some ports that are used for file sharing. I don't mind my customers downloading files, this is not the problem. The problem occurs when a customer uses a file sharing program, they are also allowing everyone throughout the whole world to download that same file off their computer. When this happens, thousands of non-customers use up all of the available bandwidth reserved for "YOU" my customers.

This results in slower speeds! 

Another reason I am shutting down some of these ports is due to viruses. Several viruses use some of these ports to infect customers computers. They can be used to send Spam from unsuspecting computers. Some of the ports I will be blocking will reduce the amount of bandwidth used, and damage done from computers infected with spy-ware. If I suspect your computer is infected with spy-ware I will contact you, and ask you to have you computer cleaned. If you don't have the spy-ware removed from your computer after a reasonable amount of time I will be forced to temporarily disconnect you until it has been done! If I find that a customer is intentionally attempting to bypass the blocked ports, they will be permanently disconnected! If you require a certain port to remain open let me know. I'm not an unreasonable person. If you have a valid reason I'll leave it open!

- kbps -
kilobits per second [kb]. 
A bit rate expressed in thousands of bits per second.

- kBps -
kilobytes per second [kBps]. 
A bit rate expressed in thousands of bytes per second.

- Kb -
kilobit [kbps]. Approximately 1,000 bits.

- KB -
kilobyte [KB]. Approximately 1,000 bytes.

About bandwidth units

You will often see bandwidth and transfer speed quoted in two different units: kilobits per second, abbreviated kbps or Kb/s, and kilobytes per second, abbreviated KB/s. 
The difference between the two units is the number of bits in a byte, which is 8. The small 'b' stands for bits, and the big 'B' stands for bytes. Transfer speeds are often shown in KB/s, and connect speeds are usually quoted in Kb/s.

So, for instance, if a progress dialog for a modem shows you a download speed of 4.3 KB/s, it is the same as 34.4 Kb/s. If a progress dialog for a cable modem shows you a transfer speed of 100 KB/s, it is the same as 800 Kb/s.

Mbps
(1) When spelled Mbps, short for megabits per second, a measure of data transfer speed (a megabit is equal to one million bits). Network transmissions, for example, are generally measured in Mbps.

(2) When spelled MBps, short for megabytes per second.

T-1 carrier
A dedicated phone connection supporting data rates of 1.544Mbits per second. A T-1 line actually consists of 24 individual channels, each of which supports 64Kbits per second. Each 64Kbit/second channel can be configured to carry voice or data traffic. Most telephone companies allow you to buy just some of these individual channels, known as fractional T-1 access.

T1 is a term coined by AT&T for a system that transfers digital signals at 1.544 megabits per second

T1 = 1.544 megabits [Mb] or 1581.056 kilobits [kb]
1 megabit [Mb] = 1024 kilobits [kb]
3 megabits [Mb] = 3072  kilobits [kb]
4.544 megabits [Mb] = 4663.296

The overhead necessary to frame a T1 is 8Kbps. Therefore, the total usable bandwidth is 1.536Mbps.

T-1 lines are a popular leased line option for businesses connecting to the Internet and for Internet Service Providers (ISPs) connecting to the Internet backbone. The Internet backbone itself consists of faster T-3 connections.

T-1 lines are sometimes referred to as DS1 lines.

Recognize that the Internet is not homogenous. Some servers may be far away and connected over slow links. You will not get fast transfer rates from these servers regardless of how fast your local connection is. You are only as fast as the slowest link (or slowest server). In other words, the best download test would be a connection to a fast server directly on your ISP's network. This kind of test eliminates the most unknowns.

Not so fast! Communications equipment vendors like to think in terms of low level ATM data rates without regard to the structure or content of the data.. ATM is a protocol for transferring data between two points. Internet uses ip as the protocol for communicating, therefore, and in particular, tcp/ip. So your data is going over your DSL line via tcp/ip over ATM.

TCP has an overhead in transmission that can be as low as 3%, but ATM overhead is more like 10% .. So you can expect to lose 13% of your purchased speed at least when counting application data transfer rate.

If you see truly awful performance to a server, say, www.download.com, then test with a ping test first. go to an MSDOS prompt, and type 'ping -t www.download.com' pinging tiny packets one a second at the destination. Watch the sequence numbers printed .. leave it running for a short time, say 30 seconds, then press control-c. Final packet loss statistics will be printed. If you see 5% or more packet loss, then TCP performance is going to be poor over this link. If no packets get through at all, you may have found a server that does not respond to ping packets, In that case, use tracert (traceroute), to identity one hop previous to the target server, and try pinging that instead.

http://www.dslreports.com/speed