Calculating network and server delay in a read transaction
When a client computer requests information from the server, the request and response are tracked to determine how long it takes for the client to send the request, and the server to send the requested data back to the client. The diagram below shows the flowthe network traffic between network objects of information between the client, the Exinda appliance, and the server, and identifies the points in the transaction where time stamps are acquired.
A visual presentation of a network read transaction.
Network Delay for Read Request (N1)
- The client sends a request to the server.
- When the request passes through the Exinda, the time stamp is noted as the beginning of the request (t1).
- When the end of the request passes through the Exinda, the time stamp is noted (
t2).t2 - t1= The amount of time it takes the client request to pass through the Exinda appliance. - The server receives the complete client request.
Server Delay for Read Request (S)
- After the server receives a request from the client, the server takes some time to process the request. This is the Server delay (S).
Network Delay for Read Response (N2)
- The server’s response to the client request is sent, and may be sent in a number of packets.
- When the first response passes through the Exinda, the time stamp is noted (
t3). - When the end of the last response passes through the Exinda, the time stamp is noted (
t4).t4 – t3= The amount of time it takes the data requested by the client to pass through the Exinda appliance. - The client receives the data requested from the server.
Total Time for Read Transaction
The total transaction time for a Read transaction is calculated as Transaction time = N1 + S + N2 where:
- N1 = ½ RTTclient + (t2 – t1) + ½ RTTserver
- S = (t3 – t2) – RTTserver
- N2 = ½ RTTserver + (t4 – t3) + ½ RTTclient