Control framework design is critical to future SDN/NFV-enabled satellite network. However, the current multi-layer constellation based solutions have drawbacks in terms of availability, latency, openness, etc. The key contribution in this work is the study of an efficient control framework, which logically consists of two parts: entity part and overlay part. The entity part is a novel heterogeneous single-layer LEO satellite network, while the overlay part implements a virtualized overlay network. We have implemented a lightweight prototype of our framework and compared it with a GEO satellite based solution (i.e. OpenSAN). We demonstrate proof-of-concept that our framework performs better than OpenSAN with respect to control latency and avoids potential system bottleneck.

The proposed MSN architecture is intended to directly address the challenge of mobility, which refers to the motion of users as well as the dynamics of the satellite constellation. A virtual access point layer consisting of fixed virtual satellite network attachment points is superimposed over the physical topology in order to hide the mobility of satellites from the mobile endpoints. Then the MSN enhances endpoint mobility by a clean separation of identity and logical network location through an identity-to-location resolution service, and taking full advantage of the user's geographical location information. Moreover, a SDN based implementation is presented to further illustrate the proposal.

In this paper, we propose a rollback traffic avoidance method for the snapshot routing in cyclic mobile networks. Since the snapshot routing tables are switched simultaneously, part of the traffic may be sent back on some links if the new routing path contains the same links but with reversed forwarding direction against the old one. Since the selection of routing paths to avoid the rollback traffic is NP-hard, we propose an approximate algorithm called Inter-Snapshot Rollback Traffic Avoidance (ISRTA), to pursuit the approximate optimal solutions. Evaluation is performed based on the typical cyclic mobile network -- Iridium satellite system, and the simulation results show that our method can efficiently eliminate the rollback paths and traffic in the Iridium system.

In this paper, we propose an offline rollback traffic avoidance method for the snapshot routing in cyclic mobile networks. Since the snapshot routing tables are switched simultaneously, part of the traffic may be sent back on some links if the new routing path contains the same links but with reversed forwarding direction against the old one. To avoid the rollback traffic, we first formulate the rollback traffic avoidance problem as an integer programming problem which is NP-hard, and then we propose an approximate algorithm called Inter-Snapshot Rollback Traffic Avoidance (ISRTA), to pursuit the approximate optimal solutions. Simulation results show that our method can efficiently eliminate the rollback paths and traffic in the Iridium system. Although the global average network delay is increased slightly, the extra end to end delay caused by rollback traffic is eliminated and the packet loss rate is reduced.

In recent years, with the rapid development of satellite technology including On Board Processing (OBP) and Inter Satellite Link (ISL), satellite network devices such as space IP routers have been experimentally carried in space. However, there are many difficulties to build a future satellite network with current terrestrial Internet technologies due to the distinguished space features, such as the severely limited resources, remote hardware/software upgrade in space. In this paper, we propose OpenSAN, a novel architecture of software-defined satellite network. By decoupling the data plane and control plane, OpenSAN provides satellite network with high efficiency, fine-grained control, as well as flexibility to support future advanced network technology. Moreover, we also discuss some practical challenges in the deployment of OpenSAN.

This work presents a novel quantum security VoIP phone, called Qphone. Qphone integrates quantum key distribution (QKD) and VoIP steganography, and achieves peer-to-peer communication with information-theoretical security (ITS) guaranteeing. Qphone consists of three parts, a real-time QKD system, RT-QKD, a steganography software, VS-Phone, and an audio encryption and authentication hardware, AE-KEY. RT-QKD explores QKD technologies, and is able establish a shared key between two peers ensuring ITS. VS-Phone utilizes VoIP steganography to protect transmission channels of sensitive information. Qphone can provide efficient and real-time security protections to meet different security demands.

In the challenged networks, such as interplanetary networks, satellite networks, military networks and so on, a complete path from the source to the destination does not exist for most of the time. The lack of end-to-end path makes the message delivery a great challenge in these networks. In this paper, we propose the spray and routing message delivery mechanism, which combines the simplicity of epidemic routing and the efficiency of direct routing. We evaluate the performance of Spray and Routing via simulation using the ONE simulator, in comparison with the traditional Epidemic, Prophet and Spray and Waiting protocols. The simulation results show that our method can achieve better performance.

With the rapid development of various types of space applications, space information network faces more and more challenges about the quality of service. How to provide end-to-end QoS based on the limited resources of space information network becomes one of the research focuses. In this paper, a method of dynamic deprivable bandwidth allocation (DDBA) is proposed for delay-sensitive specific applications. Applications are classified to three service levels according to the sensitivity of the delay. High level of services can deprive the bandwidth which has been allocated to the low level of services under certain situation. The results of the simulation illustrate that DDBA improves the use efficiency of the limited bandwidth compared to those typical bandwidth allocation algorithms. Furthermore, the DDBA can also reduce the delay of high level DS services and depress the lost rate.

One way to improve the throughput of a wireless ad hoc network at the media access (MAC) layer is to allow as much as possible concurrent transmissions among neighboring nodes. In this paper, we present a novel high-throughput MAC protocol, called Concurrent Transmission MAC(CTMAC), which supports concurrent transmission while allowing the network to have a simple design with a single channel, single transceiver, and single transmission power architecture. CTMAC inserts additional control gap between the transmission of control packets (RTS/CTS) and data packets (DATA/ACK), which allows a series of RTS/CTS exchanges to take place between the nodes in the vicinity of the transmitting or receiving node to schedule possible multiple, concurrent data transmissions. To safeguard the concurrent data transmission, collision avoidance information is included in the control packets and used by the neighboring nodes to determine whether they should begin their transmissions. Also, to isolate the possible interference between DATA packets and ACK packets, a new ACK sequence mechanism is proposed. Simulation results show that a significant gain in throughput can be obtained by the CTMAC protocol compared with the existing work including the IEEE 802.11 MAC protocol.