Leased Lines

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  • Topic: Synchronous optical networking, T-carrier, Wavelength-division multiplexing
  • Pages : 3 (697 words )
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  • Published : December 1, 2012
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Leased Lines

Below what speed are there different leased line standards in different parts of the world? In the text “Business data networks and telecommunications” the author points out that leased lines vary worldwide from 56 kbps to several gigabits per second, depending on the technology used. The lowest speeds of these leased lines are 56 or 64 kbps in the United States, and 64 kbps in Europe. These speeds are comparable to modem speeds and are rarely installed. The typical wiring for these types of lines is 2 Pair Data-Grade UTP. Additionally, it should be noted that leased line speeds vary greatly in countries other than the United States and Europe and (Panko & Panko, 2011). What is the exact speed of a T1 line?

The T1 line in the United States operates at 1.544 Mbps (Panko & Panko, 2011). However, it should be noted that the actual payload value of a T1 is 1.536 Mbps. According to Bell Labs – the inventor of T1 technology - the reason for the difference is T1 lines use UTP wiring with a digital not analog signal. The stream starts with bits arranged in 24 channels of 8 bits each - sampled at 8 KHz. The total then is 64 Kbps per channel. Thus there are 24 channels at 64 Kbps per channel, which when multiplied offers 1,536 Kbps – or the actual graded speed of a T1 line (Bell Systems, 2012). What are the speeds of comparable leased lines in Europe?

In Europe the line that is comparable to the United States T1 is the E1 - also known as the CEPT-1. The E1 integrated line operates at a rate of 2.048Mbps. Additionally, the typical transmission standard for both T1 and E1 lines is the 2 Pair Data-Grade UTP wire (Panko & Panko, 2011). The chart below details the speed variation between the T1 and E1 leased lines.

| | | |
| United States T1|  | European E1|
Speed| 1.544 Mbps|  | 2.048 Mbps|
Wire | 2 Pair Data-grade UTP|  | 2 Pair Data-Grade UTP| | | | |
Why are fractional T1 and E1 speeds...
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