Research And Implementation Of Anycast Mechanisms In NDN

Presently, the user's Internet access mode is shifted from end-to-end communication to content retrieval. The traditional TCP/IP network only transmits byte stream, unaware of what content is transmitted, causing large amount of duplicated traffic transmission in the Internet. In addition, the development of information technology, especially the rapid growth of mobile Internet, results in steady growth of network traffic, diversified network applications, and more complex network management, which makes the present Internet face several challenges in scalability,security, manageability, and mobility. Since the present network architecture is hard to meet the future requirement of network applications, the research community has proposed Information Centric Networking(ICN) as a revolutionary solution to address these challenges faced by the present Internet. Named Data Networking(NDN) is a representative architecture of ICN.As a new network architecture, NDN should be able to not only effectively cope with the challenges faced by the present Internet and address the problem of traffic explosion from the root cause, but also support the operational mode of present Internet services. Today, in order to support millions of users, a lot of large Internet services adopt the anycast service architecture. These services provide services to different users from a vast number of geographically distributed servers or server farms based on techniques such as DNS resolution and redirection, which improves the scalability,reliability and availability of these services. However, these anycast mechanisms in the Internet cannot be directly ported to NDN because of the drastic architectural difference between the TCP/IP network and NDN. Meanwhile, NDN's inherent routing-based anycast mechanism cannot satisfy the requirements for stateful and flexible anycast.Targeting the problem that NDN is unable to support flexible and stateful anycast,this thesis proposes several anycast solutions in NDN based on request redirection,request rewriting and hybrid mechanisms, and also provides a systematic comparison between different solutions.The main contributions of this thesis are listed as follows:1) Provide a comprehensive analysis of the anycast service features and application scenarios, illustrate the difference between NDN and TCP/IP network architecture ,point out the reasons why anycast mechenisms used in TCP/IP network can not be directly ported to NDN and present the challenges of supporting anycast in NDN.2) Focusing on stateful and flexible anycast requirement, this thesis proposes several anycast solutions for NDN, and provides a systematic evaluation of these solutions based on scalability, flow affinity, transparency, flexibility and service response time. Qualitative analysis shows that the hybrid anycast mechanism can have balanced performance in all aspects, which could effectively meet the stateful and flexible anycast requirement.3) Serveral first layer policies and second layer policies for the hybrid anycast mechanism which is based on redirect and rewriting are proposed. Based on the OMNet++ simulation platform and ccnSim, the hybrid anycast mechanism with different policies is implemented, its correctness is verified, and its performance is evaluated.