Empowering Software Defined Wireless Networks Through Media Independent Handover Management Carlos Guimar˜aes1, Daniel Corujo2, Rui L. Aguiar3 Instituto de Telecomunicac¸ ˜oes Universidade de Aveiro, Portugal Globecom 2013 SDN환경에서 seamless한 핸드오버 실험.

content Introduction Structural elements of proposed framework Handover procedure Evaluation Conclusion

IEEE 802.21 + SDN = Proposed Handover management 1. Introduction IEEE 802.21(or Media Independent Handover(MIH)) defines extensible access media independent mechanisms that facilitate and optimize handovers between heterogeneous networks. IEEE 802.21 provide OpenFlow with link information to select the best handover candidate and to optimize the usage of network resources. SDN divide the network operation between the control plane and the data plane. IEEE 802.21 + SDN = Proposed Handover management IEEE 802.21 WG(Working Group)은 이종망(무선랜, 와이맥스, 셀룰러 망 등) 간에 끊김없는 핸드오버를 지원하기 위한 프레임워크 및 메커니즘에 대한 기본 표준이다.

IEEE 802.21 WG(Working Group)은 이종망(무선랜, 와이맥스, 셀룰러 망 등) 간에 끊김없는 핸드오버를 지원하기 위한 프레임워크 및 메커니즘에 대한 기본 표준이다.

IEEE 802.21 WG(Working Group)은 이종망(무선랜, 와이맥스, 셀룰러 망 등) 간에 끊김없는 핸드오버를 지원하기 위한 프레임워크 및 메커니즘에 대한 기본 표준이다.

IEEE 802.21 WG(Working Group)은 이종망(무선랜, 와이맥스, 셀룰러 망 등) 간에 끊김없는 핸드오버를 지원하기 위한 프레임워크 및 메커니즘에 대한 기본 표준이다.

IEEE 802.21 WG(Working Group)은 이종망(무선랜, 와이맥스, 셀룰러 망 등) 간에 끊김없는 핸드오버를 지원하기 위한 프레임워크 및 메커니즘에 대한 기본 표준이다.

2. Structural elements of proposed framework OpenFlow Controller / PoS: This is the heart of the proposed framework, being responsible not only for performing routing related tasks, such as updating forward tables of OpenFlow Switches, but also for handling and controlling mobility procedures. OpenFlow Switch / PoA: This entity is responsible for executing data packet forwarding operations, via a flow table. Mobile Node: End-user equipment that allows the user to connect to the network. MN is able to provide events about detected PoAs or indicating that the current PoA’s signal level is decreasing past a predefined threshold, as well as to receive commands to execute handovers to other PoAs.

2. Structural elements of proposed framework Mobility Manager: Coupling the operations of OpenFlow and IEEE 802.21. SAP(Service points): It allows the Mobility Manager to control aspects of the link interface regarding handover management.

3. Handover procedure   MN detects a new PoA on its surroundings based on several information (i.e., link technology or signal strength). MN triggers a MIH MN HO Candidate Query.request towards its PoS including handover request. (4) Before the PoS replies to the MN, it queries the resources availability on each detected PoA by exchanging MIH N2N HO Query Resources messages with each PoA. (5) Provide to the MN an ordered list about the best candidate networks. (6) The MN selects the handover candidate and issues a MIH MN HO Commit.request message. (7) PoS informs the PoA that a MN is about to move to its network and that any necessary link resources should be prepared

3. Handover procedure   (9) the PoS issues an OFPT FLOW MOD (9) message towards, not only to the PoA, but also to other OpenFlow switches under the domain of the PoS in order to update their forwarding tables. (12) The PoS issues a MIH MN HO Commit.response message towards the MN, confirming that the resources were successfully prepared by the network. (16, 17) The POS sends a OFPT FLOW MOD message sends a OFPT FLOW MOD message to all switches that maintain a route related with the MN and the old PoA. (19, 20) When the old communication is completed, the PoS requests the old PoA to release all resources associated with the MN (MIH N2N HO Complete messages. (21) The PoS acknowledges the MN that the handover procedure was completed by sending a MIH MN HO Complete.response message.

4. Evaluation  

4. Evaluation Fig. 4: Link utilization Fig.4(a)를 보면 모빌리티 어워니스가 없으면 MN이 POA2나 POA3로 이동하여도 인식하지 못하여 POA1의 링크만 계속 사용하여 데이터를 전송하는 것을 알 수 있다. 이는 handover의 실패를 의미하고 무의미하게 POA1의 링크만 낭비하게 되는 것 을 의미한다. Fig.4(b)에서는 MN의 이동은 인식하지만 Seamless한 핸드오버는 지원하지 못하기 때문에, 10초와 20초 handover가 일어나는 시점에서 링크 사용이 0이 되고 이로 인한 loss가 발생함을 알 수 있다. 또한, 링크 사용의 오버랩이 없음을 알 수 있는데, 이는 old path를 유지 않았음을 보여준다. Fig. 4: Link utilization

4. Evaluation   이 논문에서 제시한 framework를 적용하면, 다음 표와 같이 IEEE802.21 적용으로 인한 딜레이와 패킷 사이즈 증가를 유발한다.

4. Conclusion   These framework allows handover-enhancement processes, provided by configurable indications from wireless link conditions and handover opportunities associated to Mobile Node movement, to dynamically and preemptively trigger software-defined flow configuration, minimizing the impact to on-going data sessions and increasing connectivity opportunities.