Want to create a one to one chat in site using SignalR?

Dear Sir/Madam,

I want to add one to one chat functionality to site but facing proble how to make a one to one chat using signalr.As i am in doubt that how to reply the client using the connectionid(clients.caller(connectionID)) which will get changed if he close the browser or get logout.So is it a good idea to save the connection id which is not always unique.