Flow Mobility in Internet
▶ Introduction

How can we explain IP Flow Mobility in a sentence? “Seamless IP Mobility with the support of vertical handover

Since the era of All-IP networks is drawing near and the prevalent use of mobile devices, which demands for anywhere, anytime and anyway high speed internet access, is being accelerated more and more, the importance of IP Mobility has been increased as the time passes. Mobile IP (or IP mobility) is an Internet Engineering Task Force (IETF) standard communications protocol that is designed to allow mobile device users to move from one network to another while maintaining a permanent IP addresses which enables the ‘Seamless Communication’.

IP Flow Mobility is to support IP Mobility on the devices with two interfaces or more, with the combinations, for instance, LTE-Wifi or LTE-Wimax-Wifi, as we have observed those on the cell phone we use everyday. It is possible with the existence of neutral layer between Data-Link layer and IP layer that hides the relocation of IP flow to appropriate/desired interface from higher layer. To implement this ‘2.5’ layer, as IEEE proposed, Media Independent Handover (MIH) is suggested from IEEE 802.21 Working Group, and also, IETF NETEXT Working group proposed Logical Interface for Proxy Mobile IPv6 which is core network-structure for supporting IP Mobility nowadays.

To support the IP mobility, the modification on both of network and client is inevitable. To minimize the impact of systematic change, network-based IP mobility is recommended when it is to be implemented. The idea of network-based mobility is to give the control to the network entity like Access Point (AP), not to the mobile device, so that the client(user) doesn’t need to alter the device or system. The advantage of network-based mobility, moreover, is that it can save the energy or network resources the client consumes.

The issues on the IP flow mobility is simplifying and securing the procedures for mobility management. Streamlined signaling yields fast handover and better performance. And, since the transition from desktop to mobile devices for every communications and transactions is progressing, the concern on the security issues of wireless communication is also being raised. The threats such as eavesdropping the mobility-related signals or falsifying the network entities are to be considered with enhanced structure or procedures.

The development of IP Flow Mobility is still ongoing. So, finding novel/improved ways to support it with better performance, security or compatibility with the existing network is the Key issue on this topic.

The structure of LTE network and Proxy Mobile IPv6 is similar to an entity which anchors all traffic to itself.(LMA or ePDG). With no need to change the existing network topology, service providers found it easy to apply this technology to their network. LG U plus, the one of major telecommunication company in Korea, has been applying it to not only their network but also the mobile device by providing the way to modify the system kernel. Other operators also have prepared the LTE-Wifi seamless service since 2011 and stared to apply it from 2012.

▶ Research Issues

  • Network structure design for Flow mobility
  • Compatibility(or minimal change) with existing system
  • Minimizing delay during handover procedure
  • Security issue on mobility signaling and network entities
  • How to apply the technology to real world effectively?
  • Interoperability with other technologies or policy

  • ▶ References

    1. Wikipedia, Mobile IP, http://en.wikipedia.org/wiki/Mobile_IP
    2. IEEE 802.21, IEEE Standard for Local and metropolitan area networks - Part 21: Media Independent Handover Services
    3. 3GPP TS 23.402, Architecture enhancements for non-3GPP accesses
    4. 3GPP TS 23.261, IP flow mobility and seamless Wireless Local Area Network (WLAN) offload; Stage 2
    5. IETF RFC5213, Proxy Mobile IPv6, RFC6088, Traffic Selectors for Flow Bindings
    6. IETF Draft. Logical Interface Support for multi-mode IP Hosts, Proxy Mobile IPv6 Extensions to Support Flow Mobility
    7. IP flow mobility: smart traffic offload for future wireless networks, 2011, A de la Oliva et al.

    ▶ Achievements