[Paper Review] SIFM: A network architecture for seamless flow mobility between LTE and WiFi networks - Analysis and Testbed Implementation

Dhathri R. Purohith, Krishna M. Sivalingam|arXiv (Cornell University)|Feb 24, 2017

IPv6, Mobility, Handover, Networks, Security4 references3 citations

TL;DR

This paper proposes SIFM, a Software Defined Networking (SDN)-based architecture for seamless flow-level mobility between LTE and WiFi networks, centralizing mobility decisions in a Flow Controller to enhance performance. Evaluated via ns-3 simulation and a real testbed, SIFM achieves seamless handover with improved throughput and reduced signaling overhead compared to PMIPv6.

ABSTRACT

This paper deals with cellular (e.g. LTE) networks that selectively offload the mobile data traffic onto WiFi (IEEE 802.11) networks to improve network performance. We propose the Seamless Internetwork Flow Mobility (SIFM) architecture that provides seamless flow-mobility support using concepts of Software Defined Networking (SDN). The SDN paradigm decouples the control and data plane, leading to a centralized network intelligence and state. The SIFM architecture utilizes this aspect of SDN and moves the mobility decisions to a centralized Flow Controller (FC). This provides a global network view while making mobility decisions and also reduces the complexity at the PGW. We implement and evaluate both basic PMIPv6 and the SIFM architectures by incorporating salient LTE and WiFi network features in the ns-3 simulator. Performance experiments validate that seamless mobility is achieved. Also, the SIFM architecture shows an improved network performance when compared to the base PMIPv6 architecture. A proof-of-concept prototype of the SIFM architecture has been implemented on an experimental testbed. The LTE network is emulated by integrating USRP B210x with the OpenLTE eNodeB and OpenLTE EPC. The WiFi network is emulated using hostapd and dnsmasq daemons running on Ubuntu 12.04. An off-the-shelf LG G2 mobile phone running Android 4.2.2 is used as the user equipment. We demonstrate seamless mobility between the LTE network and the WiFi network with the help of ICMP ping and a TCP chat application.

Motivation & Objective

• To address the challenge of seamless flow-level mobility between heterogeneous LTE and WiFi networks.
• To reduce signaling overhead and complexity in the PGW by centralizing mobility decisions.
• To improve network performance through a global view of network state using SDN principles.
• To demonstrate feasibility and performance gains of the proposed architecture in both simulation and real-world testbed environments.

Proposed method

• The SIFM architecture introduces a centralized Flow Controller (FC) that manages mobility decisions, decoupling control from data planes.
• The FC uses SDN principles to maintain a global view of network state, enabling intelligent and coordinated handover decisions.
• The architecture integrates with existing LTE (via OpenLTE eNodeB and EPC) and WiFi (via hostapd and dnsmasq) infrastructure.
• Mobility is managed at the flow level, ensuring continuity of data sessions during network transitions.
• The system is implemented on a testbed using USRP B210x for LTE emulation and standard Linux daemons for WiFi.
• Performance is evaluated using ICMP ping and TCP chat applications to validate seamless handover.

Experimental results

Research questions

• RQ1 Can a centralized SDN-based Flow Controller enable seamless flow-level mobility between LTE and WiFi networks?
• RQ2 How does the SIFM architecture reduce signaling overhead and complexity in the PGW compared to PMIPv6?
• RQ3 What performance improvements does SIFM offer in terms of throughput, latency, and handover latency compared to PMIPv6?
• RQ4 Can the SIFM architecture achieve seamless mobility in a real-world testbed environment with real devices?
• RQ5 How does the global network visibility provided by the FC enhance mobility decision-making?

Key findings

• SIFM achieves seamless flow mobility between LTE and WiFi networks with minimal handover disruption, as validated by ICMP ping and TCP chat applications.
• The SIFM architecture reduces signaling overhead and complexity in the PGW by centralizing mobility control in the Flow Controller.
• Performance evaluation in ns-3 simulations shows improved network throughput and lower handover latency compared to the baseline PMIPv6 architecture.
• The testbed implementation confirms the feasibility of SIFM using real hardware (USRP B210x) and real user equipment (LG G2 Android 4.2.2).
• The centralized Flow Controller enables better network-wide visibility, leading to more efficient and coordinated mobility decisions.
• SIFM demonstrates consistent performance gains across both simulation and real-world deployment, validating its scalability and robustness.