Broadcast a message to 25 clients from the server without any delay C# asp.net

Question

I am working on a project in c# asp.net web application in which I am conducting an exam. There will be atleast 25 students taking part in the exam. There is an instructor side page where a timer periodically updates some data and it should broadcast a message to all 25 clients simultaneously.The questions to be shown to the students are depended on this message (so it should be in realtime) .Also the message should reach every client. I tried ajax polling but the application hangs when i have 10 students logged into the system . Can anyone help me with a better technology .???

*Note:- I dont want to use a timer in the client side.The message should reach every client at the same time and also should no client should miss the message. *

Answer 1

You can use SignalR. It's very good way to send near real time messages from server side to client side. It has both server and client side objects. On client it supports different transports that browser supports like WebSocket, Long Pooling, etc

Answer 2

I'd look towards something like websockets.

The first question is what exactly do you mean by "at the same time"? It's not really possible to send a message to 25 clients "at the same time". You could use UDP to broadcast the message but how would you know that all clients have received it "at the same time"?

It's a fairly tricky problem with a number of variables, such as network topology. I think you should be looking to write a custom service since ASP.NET is not really suited the situation you describe, imo.