SDN架構應用於多重無線存取頻寬聚合機制之研究

Applying SDN Architecture to Multi-RAT Bandwidth Aggregation Mechanism

楊舜能(Shun-Neng Yang) ； 顏在賢(Chai-Hien Gan) ； 林一平(Yi-Bing Lin)

《電腦與通訊》 161期 (2015/03) Pp. 43-50

摘要

行動網路的資料流量隨著智慧型行動裝置的普及而呈現快速成長，行動電信營運商試圖將網路核心設備升級來擴充服務數據容量，希望藉此解決行動數據流量快速增長的問題，但相對於呈爆炸性增長的行動數據流量而言，其成效相當有限；部分行動電信營運商提出行動數據流量卸載（Mobile Data Traffic Offloading）技術如Wi-Fi Offloading等來解決此一問題，然而此類技術僅考慮各網路的使用狀況，並未考慮數據流的特性，雖可短暫分散行動數據流量，長期而言，亦無法有效紓解逐年大幅增加之行動數據流量。有研究者嘗試透過多重網路之整合來解決此一問題，但多數相關研究皆需用戶端與伺服器端皆支援所提之協定，造成協定上使用不便之問題。是以本論文提出了基於軟體定義網路（Software-Defined Networking；SDN）之多重無線存取頻寬聚合機制，來處理LTE與Wi-Fi等多重無線存取間的傳輸路徑配置與管理。所提之多重連線接取軟體（multi-RAT adapter；MRA）與聚合控制函式（aggregation control function；ACF）分別安裝於user equipment（UE）端與SDN網路端以處理多重無線存取頻寬聚合。藉由我們提出的機制，UE端僅需安裝MRA軟體，而原本執行於UE端的應用服務不需做任何修改即可使用。則當單一網路無法滿足UE之QoS需求時（如UE執行需要高頻寬之應用服務），可經由本論文提出之基於SDN之多重無線存取聚合管理機制，依據當前網路傳輸效能與UE欲傳輸之服務流特性，提供SDN網路進行傳輸效能最佳化之網路聚合點與傳輸路徑配置決策，滿足網路中各UE之網路服務品質需求， 並提高整體網路之使用效率。

關鍵字

多重無線存取頻寬聚合 ； 穿隧與解穿隧 ； 軟體定義網路 ； 封包重排序

並列摘要

In the recent years, the mobile traffic has grown rapidly with the popularity of smart mobile devices. Mobile telecommunications operators try to upgrade the core network equipment to expand the network capacity of services, hope to solve the problem of rapidly growing mobile traffic. Unfortunately, the violent growth of mobile traffic highlighted the limitation of the upgrade. Some operators propose the Mobile Data Traffic Offloading technique such as Wi-Fi Offloading for resolving this problem. This approach tries to relief the heavy load of mobile traffic by dispersing traffic flows to other access networks; however, it only considers the usage of each network and does not distribute the data flows by their specifics. Thus in the long term, the performance of traffic offloading still cannot keep up with the year-on-year significantly increasing mobile traffic. Some researchers try to solve this problem through the integration of multi-radio access technology (multi-RAT), but most of the works require both of the clients and servers to support their proposed protocols, which cause incompatibility issue that could restrict the usage of the proposed protocols. Hence this paper proposes the SDN-based multi-RAT bandwidth aggregation mechanism, for handling the transmission path assignment and management between LTE, Wi-Fi, and other RATs.The proposed multi-RAT adapter (MRA) software and aggregation control function (ACF) are installed in user equipment (UE) and SDN side respectively for handling the multi -RAT bandwidth aggregation. Through our mechanism, the UE only needs to install the multi-RAT adapter software without impacting the application services executed in the UEs. When the QoS requirements of UE (e.g., the UE executes a high-bandwidth-required application service) could not be satisfied by a single network, our SDN-based multi-RAT bandwidth aggregation and management mechanism can provide the transmission-efficient network aggregation point and the transmission path assignment strategy to the SDN networks. Thus our solution satisfies the network QoS requirements of UEs and enhances the efficiency of whole network utilization.

並列關鍵字

multi-RAT bandwidth aggregation ； tunneling and de-tunneling ； Software-Defined Networking ； SDN ； packet reordering