I can't find solved examples on CCS anywhere, so I'm really desperate for at least one, so that I know how to solve the others.
The alternating-bit protocol works as follows. Each message sent by Sender contains an additional protocol bit, 0 or 1. When Sender sends a message, it does so repeatedly (with its corresponding bit) until it receives an acknowledgment (ACK) from Receiver that contains the same protocol bit as the message being sent. When Receiver receives a message, it sends an acknowledgment ACK to Sender and includes the protocol bit of the received message. When a message is received for the first time, the receiver delivers it for processing, while subsequent messages with the same bit are simply acknowledged. When Sender receives an acknowledgment containing the same bit as the message it is currently transmitting, it stops transmitting that message, flips the protocol bit (0->1 or 1->0) and repeats the protocol for the next message.
