Question

Computer Networks

A client-server system uses a satellite network, with the satellite at a height of 20,000 km. What is the best-case delay in response to a request?

Answer 1

Client-server system:

Server is a computer program in a machine which is used to serve other computers; it contains all data about particular stream in an organization.

• A system which contains the server program is called as server system.
• The other systems which request for any data to the server are called as clients.
• The interaction among the server and the client is represented as client-server system.
• The client machines always “requests” the data to the server.
• The server machine always “responds” or “replies” to the client’s request.
• This client-server system uses any network for interaction.

Best-case delay in response to a request:

Consider a client-server system that uses a satellite network for communication; the height of the satellite is 20,000 km.

• The diagrammatic representation of communication among the client and server is as follows:
• 

From the above diagram,

• When the client sends the request to the server, the request has to go up for 20,000 km and the response has to come down for 20,000 km.
• Likewise, the satellite sends the request to the server for 20,000 km and gets back the response for 20,000 km.
• The total path length traversed in this client-server system is 80,000 km (i.e., 20000 + 20000 + 20000 + 20000 = 80,000).
• Therefore, “Total traversed” = 80,000 km.
• Speed of light in air = 299,705 km/s.

Calculate the delay in response to a request use the following formula:

Delay = total traversed / speed of light

Apply the value "80,000" for "total traversed" and the value "299,705" for "speed of light" in the above formula.

Delay = 80,000 / 299,705

          = 0.26692 sec

Therefore, the delay in response to a request is 0.26692 sec or 266 milliseconds.

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