Research On Mobility Management And Mobility Caching Technology For Content-Oriented Network

With the rapid development of Internet technology and the widely spreading of various equipments and applications, the scale of Internet is expanding and the network traffic is exploding. The Internet need to transform from the host-to-host model to the one supports the distribution of data, content and users. Content-Oriented Network (CON) centers on the content and guides the demands. Based on the content name addressing, it supports the content to be distributed and achieved quickly. However, it faces with the problems of the universality, scalability, the defects of content management and addressing. This thesis mainly focuses on the problems of naming based mobility, subnet mobility, name convergence based distributed management and mobility caching that exist in CON. The main contributions of this thesis are as following.1. To support content name based mobility management and name addressing in CON. This thesis proposes the content location management based hierarchical mobility scheme. According to the moving scopes and the functions of network entities, the network is divided by level to manage the binding of content name and location. This scheme designs the local caching list and global caching list to manage the content name and location during the intra-domain (or inter-domain) handoff. This scheme evaluates the factors which impact the handoff overhead and gives the optimal configuration domain by the mathematical model. Meanwhile, this scheme builds the experimental topology under the ndnSIM and compares the handoff performance with other mobility schemes. These results show that the scheme in this thesis improves the handoff performance in intra-domain and inter-domain, and it decreases the handoff delay and overhead.2. To provide subnet mobility support under special network, this thesis proposes a hierarchical structure based subnet mobility scheme. This scheme builds a subnet mobility model and designs a mobile router that has two types of interfaces to support the communication connectivity. Based on the analysis of mobile router handoff sequence, this thesis proposes the access point selection strategy, state selection and forwarding strategy, optimal seletion strategy and channel scanning strategy of mobile router and access router. This thesis analyses the handoff performance of the scheme and gives the analytical expression of interrupt time interval probability. It evaluates the factors which impact the handoff performance and proposes the subnet mobility scheme of inter-domain handoff. Through the analysis of simulation, the results indicate that the scheme in this thesis decreases the handoff delay and the handoff state is stable during the frequent handoff procedures.3. To decrease the handoff overhead and delay caused by content prefix aggregation, and to solve the problems of scalability, data/control based on a centralized point and non-optimal route in the centralized mobility management approaches, this thesis proposes data and control separation based distributed mobility management scheme. In this scheme, the location update is separated from the data transmission that reduces the overload of centralized management server in core network. Meanwhile, this scheme saves a large amount of transmission overhead because of the data being transmitted through the optimal path. The location binding list is designed to cache the location and content name, and it implements the separation of content name and physical location. This thesis evaluates the factors which impact the handoff delay and handoff overhead. It also gives the analytical expression of handoff delay and handoff overhead to compare the performance with other schemes. The numerical results show that the handoff overhead is smaller than other schemes and the handoff performance is better.4. In order to break through the problem that the current cache mechanism aims at designing for fixed users, and to analyze the changing of resource allocation and content retrieving. This thesis proposes a content popularity based mobility caching scheme and adopts the specific content retrieving approach according to the content popularity. In this scheme, the content can be retrieved from nearby nodes and the resource utilization can be improved. In this thesis, it proposes a polynomial time heuristic solution to demonstrate the feasibility of this scheme, and compares the average cumulative overhead and handoff delay with the rendezvous point schemes through the simulation experiments. These results show this scheme can save a large amount of handoff overhead and delay, and it improves the utilization of network resources.