1. 1C works with AlwaysOn failover cluster, and there are several examples of using it in real life.
2. "I guess 1C should add parameter "MultiSubnetFailover=True" into connection string in order to make it works. "
MS SQL Server AlwaysOn failover should work regardless of the MultiSubnetFailover parameter. This is what MSDN says on the subject: "By default, the client tries the IP addresses in order. When the client uses the new optional MultiSubnetFailover=True parameter in its connection string, it will instead try the IP addresses simultaneously and connects to the first server that responds. This can help minimize the client recovery latency when failovers occur."
So, this parameter optimizes switching between nodes in a case of failure, but it should work anyway. I am pretty sure that this parameter has nothing to do with your issue.
3. "unable after failover to another node"
Could you, please, describe the experiment in much more detailed way? What did you do to simulate the failure? What happens next? If it was an error message, I need a full text of a screenshot of it.
4. What version of the Platform do you use?
