Question

How long will it take to transmit a GB file from one VSAT to another using a hub as shown in Figure below? Assume that the uplink is 1 Mbps, the downlink is 7 Mbps, and circuit switching is used with 1.2 sec circuit setup time.

Answer 1

solution :-

Time to transmit 1GB (Giga Bytes) file from one VSAT to another using hub:

Consider the following formula to determine the time taken to transmit the 1-GB file from one VSAT to another using hub is as follows:

…… (1)

Consider the following formula to calculate the transmission time,

…… (2)

Assume that, If the 1GB link to transfer the file in 1Gbits seconds, then

Conversion of GB to MB:

1 GB is equal to 1,024 megabytes (MB)

• 1 GB is equal to 1,024 mega bytes (MB) and 1 byte is equal to 8 bits.

Substitute the value of “number of mega bytes in a file” as “1,024” and “number of bits per byte” as “8” in Equation (2).

Consider the following formula to calculate the one-way latency:

Substitute the values of “Number of microwave links to communicate the one VSAT to another” as “4”, “Altitude of satellite in circular equatorial orbit” as “35, 800 km/sec”, and “speed of light” as “300,000km/sec” from the text book, in the above formula.

Substitute the value of “transmission time” as “8,192” sec, “one-way latency” as “0.47333” sec, and “circuit set up time” as “1.2” seconds in Equation (1).

Therefore, the time taken to transmit 1-GB file from one VSAT to another using hub is seconds.