First of all i am new to networking so i may say dumb thing in here. Considering a client-server application using sockets(.net with c# if that matters).

1. The client sends some data, the server process it and sends back a string.
2. The client sends some other data, the serve process it, queries the db and sends back several hundreds of items from the database
3. The client sends some other type of data and the server notifies some other clients

. My question is how to set the buffer size correctly for reading/writing operation. Should i do something like this: byte[] buff = new byte[client.ReceiveBufferSize] ?

I am thinking of something like this:
Client sends data to the server(and the server will follow the same pattern)
byte[] bytesToSend=new byte[2048] //2048 to be standard for any command send by the client
bytes 0..1 ->command type
bytes 1..2047 ->command parameters
byte[] bytesToReceive=new byte[8]/byte[64]/byte[8192] //switch(command type)

But..what is happening when a client is notified by the server without sending data? What is the correct way to accomplish what i am trying to do? Thanks for reading.