Application of Contact Graph Routing in Satellite Delay Tolerant Networks

Satellite networks have many inherent advantages over terrestrial networks and have become an important part of the global network infrastructure.Routing aimed at satellite networks has become a hot and challenging research topic.Satellite networks,which are special kind of Delay Tolerant Networks(DTN),can also adopt the routing solutions of DTN.Among the many routing proposals,Contact Graph Routing(CGR) is an excellent candidate,since it is designed particularly for use in highly deterministic space networks.The applicability of CGR in satellite networks is evaluated by utilizing the space oriented DTN gateway model based on OPNET(Optimized Network Engineering Tool).Link failures are solved with neighbor discovery mechanism and route recomputation.Earth observation scenario is used in the simulations to investigate CGR's performance.The results show that the CGR performances are better in terms of effectively utilizing satellite networks resources to calculate continuous route path and alternative route can be successfully calculated under link failures by utilizing fault tolerance scheme.

Gateway Selection in MANET Based Integrated System: A Survey

Taking advantage of spontaneous and infrastructure-less behavior, a mobile ad hoc network （MANET） can be integrated with various networks to extend communication for different types of network services. In the integrated system, to provide inter-connection between different networks and prnvide data aggregation, the design of the-gateway is vital. In some integrated networks with muhiple gateways, proper gateway selection guarantees desirable QoS and optimization of network resource utilization. However, how to select gateway efficiently is still challenging in the integrated MANET systems with distributed behavior terminals and limited network resources. In this paper, we examine gateway selection problem from different aspects including information discovery behavior, selection criteria and decision-making entity. The benefits and drawbacks for each method are illustrated and compared. Based on the discussion, points of considerations are highlighted for future studies.

Update Chain-based Approach for Checking Route Oscillation of BGP

This paper presents a novel approach for checking route oscillation of border gateway protocol（BGP） quickly,by which the privacy of routing policies of autonomous system（AS） can be respected.Firstly,route update chain tag（RUCT） is constructed to track the forwarding of update report,and local routing library is made to record the changing history of update report.Then route oscillation can be identified by analyzing correlative state of RUCT and local routing library.The characteristic of this approach is that an arbitrary AS can check route oscillation alone only by sharing its network ID,which greatly respects the pri-vacy of routing policies for each AS.This paper shows that both looping in RUCT and consecutive positive-negative report in local record are sufficient conditions for route oscillation.Comparative experiments demonstrate the availability and efficiency of the proposed approach.