Distributed mobility for future mobile Internet

Abstract

The cellular networks, which are currently serving 6 billion cellular phones and mobile devices globally, have employed centralized control with different network functions arranged in a hierarchy.

Standardization of Internet mobility management in the Internet Engineering Task Force (IETF) has been primarily in centralized mobility management including Mobile IPv6 (MIPv6) and its extensions, and the deployments have primarily been in a centralized manner for the hierarchical cellular networks. Yet there are already numerous variants and extensions of MIPv6 including Proxy Mobile IPv6 (PMIPv6), Hierarchical MIPv6 (HMIPv6), and Network Mobility (NEMO), which have been developed over the years owing to the different needs that are found afterwards. Deployment of Internet mobility mechanisms can then become complicated, especially when interoperability with different deployments is an issue.

The Internet has employed distributed control functions and is more flattened, i.e., less hierarchical. As the cellular networks converge with the Internet and may become more flattened, the needed mobility management functions are expected to be distributed rather than centralized. Despite the large amount of standards work in Internet mobility in IETF primarily with centralized mobility, the deployment in the Internet is still slow. Such a fundamental change to distributed mobility is needed in the mobile Internet.

Mobility management with centralized mobility anchoring in existing hierarchical mobile networks is quite prone to suboptimal routing and issues related to scalability. Centralized functions present a single point of failure, and inevitably introduce longer delays and higher signaling loads for network operations related to mobility management. To make matters worse, there are numerous variants of Mobile IP in addition to other protocols standardized outside the IETF, making it much more difficult to create economical and interoperable solutions.

The existing mobility management standards in IETF, the issues of mobility management for the future mobile Internet, the trend of the mobile Internet and the proposed distributed mobility at IETF are explained. It will provide a fundamental understanding of broad subject of mobility management but will be presented in terms of easily understandable concepts for a diverse audience.