IWS/WDE question - failover to backup

Hi All,

Can you please advise why IWS/WDE doesn’t disconnect when T server failover from primary to backup? What is the mechanism in these two softphones that prevent it from disconnect? Thanks

Which TServer?
Which type of redundancy?
If hot, why should it disconnect?

CUCM T server, it fail over because of slow network / disconnection, hot standby. I just wonder how IWS understand that t server has failed over and it still function. thanks

Based on T-Lib event communication