A SDN-Based Controller For Securing Cloud Tenant Networks

In the paradigm of Infrastructure-as-a-Service(IaaS)cloud,the virtual IT infrastructure requested by the enterprises or institutions from IaaS cloud provider constitutes Tenant Networks(TN for short).To isolate TNs from each other,it is natural to use Software-Defined Networking(SDN),or more specifically the virtual SDN(vSDN)technology,to virtualize a cloud into TNs.However,the current vSDN uses a SDN hypervisor to attain TNs,where the cloud administrator is given much-more-than-necessary privileges,meaning not only a violation of the security principle of least privilege but also a serious threat of malicious or innocent-but-compromised administrator.Therefore,how to securely manage TN in cloud is a topic worthy of study.A SDN-based controller for securing cloud TNs,named TNGuard,is secure,efficient and extensible.To manage TNs securely,TNGuard defines a specification of TN management,called TN abstraction,which specifies the TN's function requirements and security requirements,obeying the principles of least privilege and separation of duty.To protect TNs from cloud administrator,TNGuard designs network privilege model and integrity management mechanism,which removes cloud administrator's unnecessary privileges and protects the controller's integrity separately.To improve the system response efficiency,TNGuard moves TN_admins' Apps from their local computers to the cloud,which reduces the communication overhead between Apps and controller.TNGuard meets all the requirements in TN abstraction and can be easily extended to other platformsExperimental results show that TNGuard can effectively defend cloud administrator's attacks against TNs.As for performance,the boot time of TNGuard is 2.635 seconds,which only takes a 2.9% extra time compared to traditional SDN controller.TNGuard's average response efficiency is high,and its cross-zone communication rate is about 200M/s,would be sufficient for most,if not all,applications.In summary,TNGuard enhances the TN security and incurs a small performance overhead.