Yong Geun Hong

Application translation for IPv6 at NAT-PT

The next generation Internet protocol, IPv6 which uses 128 bits Internet addresses will replace the current IPv4 protocol gradually from 2005. After 2010 IPv6 will be the main ocean of Internet or network. But until completely transition to IPv6, IPv4 and IPv6 will coexist and network devices must support IPv4 and IPv6 at the same time. Especially general users want to use Internet and applications without big changes even if networks are changed to IPv6. This paper describes ALG (application layer gateway) for IPv6 which translates application layer data in NAT-PT transition mechanism. With the design and implementation of DNS-ALG and FTP-ALG, we research the application layer gateway and examine the relationship between IP layer translation and application layer translation. As IPv6 is more deployed, not only IP layer translation, but also application layer translation has more necessity.

Distributed admission control protocol for end-to-end QoS assurance in ad hoc wireless networks

To reserve end-to-end bandwidth in quality of service (QoS) supported wireless ad hoc networks, local bandwidth requirement should be carefully determined by considering the number of contending nodes in an interference range. In this article, we propose a novel admission control protocol, called DACP (distributed admission control protocol), which is implemented over a reactive ad hoc routing protocol with minimal overhead. DACP computes the required bandwidth for end-to-end band-width provision at each node and estimates the available bandwidth at the medium access control layer. After that, DACP makes a decision for admitting a flow in a per-hop basis. Extensive simulations are carried out via the OPNET simulator. The simulation results demonstrate that DACP not only provides guaranteed end-to-end resource but also reduces the control overhead to provide QoS support, compared with the existing admission control schemes.

Dynamic home network prefix assignment for multi-homing in proxy mobile IPv6

Proxy Mobile IPv6 (PMIPv6) supports multi-homing where a mobile node can connect to a PMIPv6 domain through multiple interfaces for simultaneous access. However, for an interface handoff, PMIPv6 does not allow simultaneous access since all the home network prefixes associated with one interface are associated with another interface of a MN. In this paper, we propose a dynamic home network prefix assignment (DHNPA) scheme where both the fixed prefix model and shared prefix model are used for simultaneous access. Simulation results show that the DHNPA scheme can achieve simultaneous access and provide the information for handoff indication in multi-homing scenario.

p-persistent frame replication for resilient services in multi-radio wireless networks

It is an important issue to provide resilient services in wireless networks where frequent frame errors are observed. In this paper, we propose a p-persistent frame replication scheme for resilient services in multi-radio wireless networks. In the p-persistent frame replication scheme, packets are transmitted over the primary link and the packets are redundantly sent over the secondary link with probability p. In addition, cooperative retransmission is devised to minimize the overhead in retransmission. Analytical expressions for the reliability, latency, and redundancy in the p-persistent frame replication scheme are derived and validated by extensive simulations. We also develop a binary search algorithm to obtain the optimal p to minimize the redundancy while satisfying the given latency and reliability requirements.