Today with optimized and highly specialized coding some companies have been able to sustain 2000 simultaneous calls using only one server and a single 100 mbit connection.
From the en.wikipedia.org
More examples
Megabit: a unit of information equal to 1000 kilobits or 10^6 (1,000,000) bits
A megabit is an SI-multiple (see prefix mega) of the unit of bit for digital information storage or transmission. The International Electrotechnical Commission's standard IEC 60027 specifies the symbol to be Mbit, but Mb is also in common use.
(Mbit/s) In telecommunications, bit rate or data transfer rate is the average number of bits, characters, or blocks per unit time passing between equipment in a data transmission system. This is typically measured in multiples of the units bit per second or byte per second.
(Mbit/s) A measurement of data-transfer speed. A megabit is one million bits.