SDN無線網路行動管理方法

Mobility Control Method for SDN-based Wireless Networks

黃貴笠(Kuei-Li Huang) ； 劉家隆(Chia-Lung Liu) ； 顏在賢(Chai-Hien Gan)

《電腦與通訊》 161期 (2015/03) Pp. 51-58

摘要

現階段的軟體定義網路（Software-Defined Network；SDN）在行動裝置換手時必定產生SDN訊息的交換以及繞送規則重新設定的動作，使得切換無線接取點（AP）的程序增加了額外的延遲。而這樣的動作所產生的延遲時間取決於網路的規模以及當時網路的狀況，時間可能達一千多毫秒，造成切換無線接取點的延遲時間過長，服務品質下降。為了減少SDN訊息對切換延遲的影響，本論文提出一個在SDN網路環境下的行動管理方法，其中，Zone的概念以及繞送規則預先設定的概念，讓行動裝置切換無線接取點後就可以繞送上行的封包。此外，連線觸發的設計，讓行動裝置連線後，就主動觸發一SDN訊息給SDN控制器，以儘快更新下行繞送路由，SDN控制器在接收該訊息後，只需要調整各無線接取點以及交換器的繞送規則即可，不需要重新設定繞送規則，減少了繞送規則重新設定的時間。上述兩項設計可以減少SDN訊息對切換無線接取點延遲的影響，加速行動裝置換手。

關鍵字

軟體定義網路 ； 行動管理

並列摘要

Handovers in a software-defined network (SDN) require additional SDN signaling for routing rule re-configuration, which prolongs handover delay. The degree of the delay depends on the scale of a network and network conditions at that moment, which could be more than 1000 mini-seconds. Therefore, the service quality can be degraded. This paper proposes a mobility control method for SDN-based wireless networks where concepts of zone and routing rule pre-configuration are utilized in the proposed method to enable the function of uplink routing in the network. In addition, a proactive notification design is proposed that as a user equipment connects to the network, an SDN notification message is triggered to inform the SDN controller of a connection-established-after-handover event so as to update the downlink route for the user equipment. The route update is optimized in that the critical routes are re-configured. With the two techniques, the SDN signaling delay contributing to the handover can be mitigated in an SDN-based wireless network.

並列關鍵字

Software-Defined Network ； SDN ； Mobility Management ； MM