Software-Defined Networking in Heterogeneous Radio Access Networks TNC 2014 Conference, Dublin Hao Yu, DTU/NORDUnet May 21, 2014

2 Connect | Communicate | Collaborate Agenda Introduction Some concepts Background of the problem Problem Leveraging SDN in HRAN for Seamless Handover Across Multiple Domains Summary Questions

3 Connect | Communicate | Collaborate Introduction – RoF and HRAN RoF = radio-over-fiber Allows radio signal to be modulated and transmitted over optical fibers in order to expand the reach of a base station (NodeB/eNodeB) or a wireless router Allows various signals over the fiber to the remote radio head, providing different access simultaneously. One universal access method for mobile devices is no longer a valid scenario. Instead, multiple access methods are available in the radio access networks (RANs): 4G (LTE) 3G (W-CDMA, TD-SCDMA, CDMA2000) WLAN (Wi-Fi) Therefore, a heterogeneous RAN (HRAN).

4 Connect | Communicate | Collaborate Introduction – Handover Surrounded by different signals, mobile devices switch between them either to receive better signal or to save data usage. Switching from one access type to another is referred to as vertical handover, while keeping the access type unchanged is called horizontal handover. Problem of handover (mainly in VH): disturbance in user experience

5 Connect | Communicate | Collaborate Introduction – Handover Problem (mobility management problem) The disturbance problem can be found in both handover types. Caused by the change of the IP address acquired by the mobile device from the attached network. Problem rooted in the dual roles of IP address when it comes to mobility: Locator: by means of routing, how to reach the node that is using a specific destination address. Identifier: used by upper-layer protocols to identify the endpoints of a communication channel. Switch from one access type to another, e.g. LTE→Wi-Fi Change of IP address assigned to the mobile device Reestablishmenf the all TCP traffic Disturbance in user experience, e.g. need for re-login.

6 Connect | Communicate | Collaborate Introduction – PMIPv6 Proxy Mobile IPv6 standardized by IETF in order to provide Network-Based Localized Mobility Management support in IP networks. (Host-based has security problems) For building a common and access tech independent mobile core, cooperative with different access techs (3GPP, WLAN, etc.) Tech terms: LMD: Localized Mobility Domain MAG: Mobile Access Gateway (>1 per LMD) LMA: Local Mobility Anchor (1 per LMD)

7 Connect | Communicate | Collaborate Introduction – PMIPv6 Principle is to maintain the Home Address unchanged regardless of the change of attachment point of the mobile node. Bi-directional tunnels between LMA and MAG In a handover situation, the LMA updates the Binding Cache entry with the Proxy CoA of the new MAG, updating also the tunnel.

8 Connect | Communicate | Collaborate Problem PMIPv6 seems a pretty good solution for mobility management in a localized domain. But what about multiple domains?

9 Connect | Communicate | Collaborate Leveraging SDN in HRAN for Seamless Handover Across Multiple Domains Use case: Students/teachers using mobile learning applications on their mobile device moving to/from LTE network from/to university eduroam Wi-Fi network. Seamless handover using PMIPv6 with SDN assistance is proposed. SDN = Software-Defined Networking Decouple the control plane from the data plane Centralize the control function into one controller

10 Connect | Communicate | Collaborate Leveraging SDN in HRAN for Seamless Handover Across Multiple Domains A SDN controller connecting to LMA and MAGs per domain. Interdomain tunnels needed.

11 Connect | Communicate | Collaborate Leveraging SDN in HRAN for Seamless Handover Across Multiple Domains PMIPv6 to be enhanced for signaling path. Agreement between domains. West- east bound APIs of SDN controllers need to be standardized. Interdomain tunnels jointly set up be the SDN controllers on data path.

12 Connect | Communicate | Collaborate Some Details About the Proposal Guest LMA needs to send PBU[MN-ID, (MAG B.LMA B)] to Home LMA Home LMA considers the Guest LMA-MAG combination as a MAG. Tunnel needs to be established between Home LMA and Guest MAG (SDN controller’s help). Downlink traffic received by Home LMA first and then Guest LMA-MAG, resulting in longer traffic delay. Home Address of the mobile node is preserved.

13 Connect | Communicate | Collaborate To Summarize PMIPv6 provides network-based mobility management support in IP networks. However, there lacks the ability to provide multidomain mobility management support in PMIPv6. How to provide a seamless handover in multidomain HRAN is challenging and needs to be solved. Propose to enhance the PMIPv6 (signaling path) with the use of SDN approach (data path) to assist in solving the problem.

14 Connect | Communicate | Collaborate Questions?

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