See these all are connection oriented protocols!. So if Sender is experiencing that nothing is working perfectly [ retransmitting repeatedly] then it will think that something bad is happened [link Down or something else] , so it will stop retransmissions , and transmit agian after some random amount of times , if this also not working then again retransmit after some random amount of time agin if this is also creating problem then it will reset the entire transmission process and it will start from the Scratch [ connect establishment] ,.. during connection establishment if we didn't recieve any acknowledgement from reciever to establish connection then it will think that there is problem in server side[may be in the network] so it will terminate the connection worst case