Cisco Certified Internetwork Expert (CCIE) Practice Test

Which characteristic describes DTLS?

1. It is limited to TCP connections

2. It includes a congestion control mechanism

3. It requires an established connection for data transfer

4. It offers a more complex retransmission method

The correct answer is: It includes a congestion control mechanism

DTLS, or Datagram Transport Layer Security, is designed to provide secure communication for datagram-based applications, primarily those using the User Datagram Protocol (UDP). One of its key characteristics is that it includes a congestion control mechanism. This is vital because it enables DTLS to adapt to varying network conditions, helping to manage the flow of data effectively and ensuring reliability despite the connectionless nature of UDP. This capability allows DTLS to maintain performance and security even in scenarios where packet loss may occur. The connection-oriented nature of Transport Layer Security (TLS) is adjusted for use in a datagram context, so DTLS can still handle some aspects of flow control and error recovery while providing the same encryption and integrity protection typically associated with TLS. The other options do not accurately describe DTLS. For instance, stating that it is limited to TCP connections is misleading, as DTLS specifically works with UDP, which does not establish a connection in the same way TCP does. Similarly, the assertion that DTLS requires an established connection for data transfer does not hold, because it is designed for use in a connectionless environment. Lastly, while DTLS does implement retransmission strategies, calling it a "more complex retransmission method" does not capture its primary function or