CODEWITHSUNDEEP
network-programmingclient-server
aaronsnoswell
aaronsnoswell

Reputation: 6251

Server -> Many Clients: Simultaneous Events

Not sure what category this question falls into; perhaps general networking / design / algorithms.

For a project I am looking at having one server with multiple connected clients. After some time, when all clients have connected, the server should send a message to each client instructing them to take some action. I need to guarantee that each client will execute this action at exactly the same time. Theoretically, how can this be done? What are the practical complications I will come up against? My target platform is mobile.

One solution I can think of;

One not-really related question: Client side and server side events not firing simultaneously

Upvotes: 0

Views: 66

Answers (2)

Marjan Nikolovski
Marjan Nikolovski

Reputation: 848

In theory yes you can but not in real life. At least you should add some a validity time-slot. All actions should be in that predefined time-slot in order that action to be valid.

So basically "same moment" = "a predefined time slot". A predefined time-slot can be any value that is close to same moment or real-time.

Upvotes: 0

Odys
Odys

Reputation: 9090

It can easily be done.

You don't care about latency nor you need the same machine time at clients. The key here is to create a precise appointment.

Since clients communicate to the server, and not vice versa (you didn't say anything about it though). I can give you the following solution:

When a client connects to the server, it should send their local time.

When the server thinks it's time for the event to be set. It should send an appointment event to each client, with their local time in it. Server can calculate this.

Then, each client knows when exactly they need to do something by setting a timer till the time for their appointment comes.

Upvotes: 0

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