Advantages of DDA
- BS need not be TCP aware so TCP headers can be ciphered.
- Recovery from wireless loss is possible without a response from Foreign Host.
- It can be used with IPsec.
- It can work even when the IP payload is encrypted.
Delayed Duplicate Acknowledgement(DDA)
Pre-requisites: TCP Snooping
The delayed duplicate acknowledgment or DDA approach is intended to be a modification of the Snooping TCP approach. As you know Snooping TCP is designed to solve the end-to-end semantics loss in I-TCP, DDA is also no different. It uses link-level transmission to recover from losses. Whenever there is a packet loss detected by the TCP, it reacts by reducing the congestion window even when the loss is due to wireless non-congestion-related losses, which heavily affects the TCP performance. DDA tries to improve this aspect of TCP.