TCP-NCL: A unified solution for TCP packet reordering and random loss

The problems of TCP packet reordering and random loss over wireless networks have motivated the development of a number of TCP variants. However, most of these variants focus on resolving only one of the aforementioned two problems. A few unified solutions for both problems generally extend beyond the scope of the transport layer. In this paper, we propose a new TCP variant, known as TCP for non-congestion loss (TCP-NCL), to tackle both problems under one compact framework. Different from previous unified solutions, the modifications are limited to sender-side TCP only, thereby facilitating possible future wide deployment. A retransmission decision timer and a congestion response decision timer have been installed to trigger packet retransmission and congestion response, respectively. Our simulation studies reveal that TCP-NCL is robust against packet reordering as well as random packet loss while maintaining responsiveness against situations with purely congestive loss.