SDN Consistency

Software Defined Networking (SDN) allows the construction of virtual networks on top of a datacenter network infrastructure. However, the flexibility also increases the chance of inconsistencies in the network configurations caused by component failures, software bugs, or human errors. The inconsistencies may result in service outage or security policy violation. We propose a model-based verification system to check the consistency of a virtual network. The system models the requirements as logic constraints and extracts the configuration states of a virtual network. The configuration states are checked against the logic constraints by using a SMT solver. The prototype system successfully detects various inconsistencies injected to the testbed and incurs reasonable amount of overheads.

FUSION: A Unified Application Model for Virtual Mobile Infrastructure

We proposed a unified application model for virtual mobile infrastructure called FUSION. FUSION bridges the gap between the remote VMI server and the client-side mobile device via supporting bi-directional IPC(inter-process communication) and loosely synchronized file system. FUSION classifies IPC events into two types: IPC events without accessing local resources and IPC events accessing local resource. For IPC events without accessing local resources, FUSION simply hooks the IPC events, forwards them to the remote peer and replays them in the remote environment. For complex IPC events involving with accessing files located in the local device, FUSION will analyze each individual IPC event and transmit the corresponding files to the remote peer with respect to each IPC event. Once the remote application completes its job and the user tries to disconnect with the remote peer, FUSION will synchronize those files back to the local side. The synchronization makes the file changes updated by the remote application visible to the local side. Base on our experimental results, FUSION incurs less than 1% overhead on the system. For simple IPC events without local resource access, FUSION can transmit those IPC events to the remote peer under various network conditions in less than 1200ms. For complex IPC events involving local resource access, FUSION can also serialize and transmit the files efficiently.

Mobile Device Management

對於攜入個人智慧行動裝置(Bring Your Own Device)於軍事管制區,目前國防部已著手導入行動裝置管理(Mobile Device Management)第三方解決方案來處理其所造成的資安隱憂。但由於管制區內的人事物有其敏感性,若僅仰賴第三方解決方案,恐形成一極大的國安漏洞。因此在本研究中我們對Android智慧行動裝置安全管控各項功能之實作可行性進行評估進而掌握其背後所需的關鍵技術,包括如裝置資訊取得、裝置控制、管控系統自體防護以及架構設計等。本研究的成果可立即作為國防部於初期導入第三方MDM解決方案的採購評量參考,而針對中長期須自行開發MDM系統的目標,本研究所發展的諸項關鍵技術也將具有極高的參考價值。

VM WAN Migration

Conventional virtual machine (VM) migration focuses on transferring a VM’s memory and CPU states across host machines. The VM’s disk image has to remain accessible to both the source and destination host machines through shared storage during the migration. As a result, conventional virtual machine migration is limited to host machines on the same local area network (LAN) since sharing storage across wide-area network (WAN) is inefficient. As datacenters are being constructed around the globe, we envision the need for VM migration across datacenter boundaries. We thus propose a system aiming to achieve efficient VM migration over wide area network. The system exploits similarity in the storage data of neighboring VMs by first indexing the VM storage images and then using the index to locate storage data blocks from neighboring VMs, as opposed to pulling all data from the remote source VM across WAN. The experiment result shows that the system can achieve an average 66% reduction in the amount of data transmission and an average 59% reduction in the total migration time.



Android Application Synchronization

隨著智慧裝置的普及,每個手上的智慧裝置也越來越多,當手上的智慧裝置越來越多時,我們會希望能把所有的 app data(app data 為 app 在/data/data 下所存放的屬於該 app 的系統資料,內容包括了該 app 的設定、有關該 app 的所有的資料。ex: 若該 app 是一款手機遊戲,在該目錄下所存放的 app data 可能就包括目前的遊戲紀錄。若該 app 是一款通訊軟體,該 app data 就可能存放著通訊歷史紀錄等。)都能夠保存下來,並且讓不同裝置間的 app 資料能夠透過雲端或者直接在本地端進行同步,能對使用者帶來極大的便利性。
而目前 Android 上,對於 app data 的備份的解決方法也有一些工具可以使用,但是目前的解決辦法都需要使用者對他們 Android device 進行 root 的動作,對於一般的使用者來說,這是一個非常不友善而且危險的方法,幾乎所有的手機廠都不支持使用者進行 root 的動作,一旦有 root 的行為,該裝置就會失去保固,這是一般使用者所不樂見的,所以我們希望能夠提供一個不需要 root 的方法進行備份、同步、分享的動作。

VM memory demand projection

Virtualization technology has been widely adopted in IaaS cloud computing environment. Through virtualization, the processor, network, and storage resources can be transparently shared at fine granularity, but the memory still requires explicit coarse-grained provisioning in most cases. Yet it is not always clear how much memory should be provisioned for a virtual machine (VM). It depends on the application workload and characteristics of the underlying platform. We present NIMBLE, a novel system to project the memory demand of virtual machines in IaaS cloud environment. NIMBLE monitors the page swapping activities of a VM at runtime and project its memory demand by indicating the expected execution time of the application workload for each targeted guest physical memory size. This allows more intuitive and cost-effective memory resource provisioning for VMs. The experiment results indicate that NIMBLE can effectively project memory demand for selected benchmark workloads on both Linux and Windows guest VMs. The results also indicate that NIMBLE incurs negligible performance overhead.

VDC Security Monitoring

Virtualized datacenter (VDC) has become a popular approach to large-scale system consolidation and the enabling technology for infrastructure-as-a-service cloud computing. The consolidation inevitably aggregates the security threats once faced by individual systems towards a VDC, and a VDC operator should remain vigilant of the threats at all times. We envision the need for on-demand mandatory security monitoring of critical guest systems as a means to track and deter security threats that could jeopardize the operation of a VDC. Unfortunately, existing VDC security monitoring mechanisms all require pre-installed guest components to operate. The security monitoring would either be up to the discretion of individual tenants or require costly direct management of guest systems by the VDC operator. We propose the EagleEye approach for on-demand mandatory security monitoring in VDC environment, which does not depend on pre-installed guest components. We implement a prototype on-access anti-virus monitor to demonstrate the feasibility of the EagleEye approach. We also identify challenges particular to this approach, and provide a set of solutions meant to strengthen future research in this area.

MicroApp Architecting Web Application for Non-Uniform Trustworthiness in Cloud Computing Environment

An increasing number of web applications are now hosted in cloud infrastructures such as Amazon Web Services. Cloud infrastructures generally lack a uniform guarantee on security, reliability, performance, and cost. A privately owned cloud infrastructure may be considered more secure but less performant than a third-party public cloud infrastructure. Infrastructures that span across geographical regions may further incur complications on the trustworthiness of infrastructures due to the varying power of jurisdiction. Application developers have to be aware of the non-uniformity of infrastructure trustworthiness when deploying applications in the cloud. We propose the MicroApp architecture that help address the difficulty in dealing with the non-uniformity. MicroApp splits a web application into multiple micro applications. Each micro application encapsulates a port of the code and data with the same level of security and integrity requirement. The micro applications will then be deployed to corresponding infrastructures that satisfy the respective requirements. MicroApp provides an RPC mechanism to allow control flows across micro applications. The architecture can be transparently applied to existing web applications and allows an application to effectively adapt to the cloud environment.