# An SDN-Based Transmission Protocol with In-Path Packet Caching and Retransmission

## TL;DR

This paper introduces SDTP, an SDN-based transmission protocol for 5G networks that enhances data transmission efficiency through in-path caching and retransmission, utilizing a new handshake, packet format, and receiver-based loss detection.

## Contribution

The paper presents a novel SDN-based transmission protocol with in-path caching and retransmission, including a new handshake, packet format, and loss detection scheme for 5G networks.

## Key findings

- Reduced connection establishment delay
- Lower end-to-end packet transmission delay
- Effective in-path packet loss recovery

## Abstract

In this paper, a comprehensive software-defined networking (SDN) based transmission protocol (SDTP) is presented for fifth generation (5G) communication networks, where an SDN controller gathers network state information from the physical network to improve data transmission efficiency between end hosts, with in-path packet retransmission. In the SDTP, we first develop a new two-way handshake mechanism for connection establishment between a pair of end host. With the aid of SDN control module, signaling exchanges for establishing E2E connections are migrated to the control plane to improve resource utilization in the data plane. A new SDTP packet header format is designed to support efficient data transmission with in-path packet caching and packet retransmission. Based on the new data packet format, a novel in-path receiver-based packet loss detection and caching-based packet retransmission scheme is proposed to achieve in-path fast recovery of lost packets. Extensive simulation results are presented to validate the effectiveness of the proposed protocol in terms of low connection establishment delay and low end-to-end packet transmission delay.