I. INTRODUCTION
A. Deficiencies of Shortest Single-Path Routing
B. Why the Internet's Future is Unmistakably Multipath?
C. Benefits of Multipathingx
D. Challenges in Implementing Multipath Routing
E. Organization and Contributions of This Paper

II. HOW TO CONSTRUCT ROUTES?
A. Source Routing
B. Hop-by-Hop Routing
C. Overlay Routing
D. SDN-based Routing
E. Routing Metrics for Multipath Routing
F. Summary of Trends

III. HOW TO USE MULTIPLE PATHS?
A. How Many Paths to Use?
C. Load Balancing Approaches for Multipath
D. Multipath Congestion Control
E. Which Layer/Where to Perform Load Balancing/Traffic Engineering?
F. Summary of Trends

IV. OPEN ISSUES
B. Addressing Multipathingx Holistically
D. Deploying Diversity Efficiently
E. Multipathingx and Green Networking

V. CONCLUSIONS