Hidetoshi Yokota

Enhanced Next-Generation Service Overlay Networks architecture

The Web Services composition paradigm has been widely used in Information Technology (IT) and Internet environments to create Web applications that both flexible and rapidly deployable. Web Services are a key way to realize Service-Oriented Architectures (SOA). In Telecom, on the other hand, the IMS (IP Multimedia Subsystem) architecture enables valued-added services composition for IP-based networks. Several ongoing efforts - referred to as “SOA for telecom” (SOA-TEL) - are attempting to merge SOA with telecom. The objective of these attempts is to enable Telecom operators and service providers to re-use existing service building blocks while building valued-added converged Web and telephony services. These services offer seamless experiences across various networks and, therefore, richer experiences, but are more complex than typical Web Services (e.g., transaction-based). The IEEE Next-Generation Service Overlay Networks (NGSON) working group is focusing on this integration and an architecture has been proposed. In addition, NGSON specifies context-aware, dynamically adaptive, and self-organizing networking capabilities. There are, however, a number of shortcomings in the NGSON architecture. This paper identifies these shortcomings and describes a possible solution. Finally, we discuss an illustrative use case scenario to help bring clarity to our proposed “enhanced” NSGON architecture.

On reducing packet buffering for network-based fast handover cooperating with IMS

For seamless mobility in networks that use Proxy Mobile IPv6, Proxy Fast Mobile IPv6 (PFMIPv6) is being standardized. The predictive handover mode of PFMIPv6 can minimize packet loss by forwarding user data from the old mobile access gateway (MAG) to the new MAG to which the mobile terminal (MT) makes a handover and by buffering the forwarded data at the new MAG until the MT is attached to the new MAG. In the case where handover is prolonged, the user data delivered after the MT attachment results in a large delay and jitter, and could be treated as actual packet loss. We propose a novel data buffering scheme to reduce the amount of buffered user data along with the application requirements which IP Multimedia Subsystem (IMS) provides. Our scheme discards the forwarded user data in the case where the user data has large jitter, and where discarding has no substantial impact on the quality of the application. A packet-based simulation to evaluate the proposal shows that the buffered user data are reduced by up to 50% compared with unlimited buffering. The proposed scheme does not require any change to the PFMIPv6 procedure, which is an advantage in terms of implementation.