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In telecommunication networks, the transmission time, is the amount of time from the beginning until the end of a message transmission. In the case of a digital message, it is the time from the first bit until the last bit of a message has left the transmitting node. The packet transmission time in seconds can be obtained from the ''packet size'' in bit and the bit rate in bit/s as: :Packet transmission time = Packet size / Bit rate Example: Assuming 100 Mbit/s Ethernet, and the maximum packet size of 1526 bytes, results in :Maximum packet transmission time = 1526×8 bit / (100 × 106 bit/s) ≈ 116 μs ==Propagation delay== The transmission time should not be confused with the propagation delay, which is the time it takes for the first bit to travel from the sender to the receiver (During this time the receiver is unaware that a message is being transmitted). The propagation speed depends on the physical medium of the link (that is, fiber optics, twisted-pair copper wire, etc.) and is in the range of meters/sec for copper wires and for wireless communication, which is equal to the speed of light. The propagation delay of a physical link can be calculated by dividing the distance (the length of the medium) in meter by its propagation speed in m/s. :Propagation time = Distance / propagation speed Example: Ethernet communication over a UTP copper cable with maximum distance of 100 meter between computer and switching node results in: :Maximum link propagation delay ≈ 100 m / (200 000 000 m/s) = 0.5 μs 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Transmission time」の詳細全文を読む スポンサード リンク
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