Redundant trunk groups are designed to provide redundancy in the network, ensuring continuous operation in the event of a failure. If the active link in a redundant trunk group fails, the secondary link automatically takes over, maintaining the connection without manual intervention. This automatic failover is a key feature of redundant trunk groups. Additionally, Layer 2 control traffic, which includes protocols necessary for network stability and management, is allowed to traverse the secondary link to ensure proper network operations and prevent disruptions.