Joo-Chul Lee

Fast Handover for Proxy Mobile IPv6 based on 802.11 Networks

The PMIPv6 (proxy mobile IPv6) protocol provides local mobility to a mobile node without requiring any modification of the mobile node. A PMIPv6 domain contains multiple MAGs (mobility access gateway), and they advertise the same prefix to the mobile node so that the mobile node feels like it is always on the same link. However, horizontal/vertical handover still happens while the mobile node moves among MAGs in the PMIPv6 domain, and this handover could cause undesirable delay to the mobile nodes running real time applications like VoIP. To solve this problem, this paper proposes a fast handover scheme for the PMIPv6 based on 802.11 networks. This scheme uses IAPP (inter-access point protocol) to transfer context information such as the mobile nodes authentication information and HNP (home network prefix).

Considerations of Neighbor Discovery Protocol over IEEE 802.16 Networks

IEEE 802.16 issued standards for the new PHY and MAC for providing broadband wireless access network. It is characterized by very high data rates and wider range which are different from existing wireless access technologies such as IEEE 802.11 or 3G. Accordingly, the use of IPv6 over IEEE 802.16 network is currently undefined. There are several issues to be considered in deploying IPv6 over IEEE 802.16 networks. Among them, this document will describe issues related to NDP (neighbor discovery protocol) over IEEE 802.16 networks

Implementation of IPv6 prefix delegation mechanism using DHCPv6 protocol

IPv6 enables simple, automatic host configuration (T. Narten, 1998). Conversely, it does not provide any specification to automatically delegate a prefix to a router. To solve this problem, several requirements were described (S. Miyakawa, 2003) and its solution by using DHCPv6 was standardized (R. Droms et al., 2003). DHCPv6 protocol enables DHCPv6 servers to pass network configuration parameters to IPv6 nodes. DHCPv6 servers can pass IPv6 prefix delegation parameter to a router by using IPv6 prefix options for DHCPv6. The components that we need to implement prefix delegation mechanism are DHCPv6 server/client modules supporting IPv6 prefix options and router advertisement module. In this paper, we implemented DHCPv6 client supporting IPv6 prefix option and used a DHCPv6 server, router advertisement module from open source project to test implemented s/w module

The Design of Mobile Router supporting Heterogeneous Access Networks and IPv4 traversal

The roaming (or handover) between heterogeneous networks is an emerging issue of the most recent communication environment. The wide deployment of wireless networks like WLAN, CDMA or WiMax accelerates growth of chance requiring roaming across heterogeneous wireless networks. As a solution of mobility management across heterogeneous networks the MIP6 (mobile IPv6) is used generally and NEMO (network mobility), an extension of the MIP6, is used for network mobility management. In this paper we design a mobile router supporting network mobility and handover between heterogeneous networks. Since The NEMO specification supports only IPv6, the NEMO itself is not enough to be deployed in current Internet environment without the consideration of IPv4 traversal. Thus, we add a feature allowing the mobile router to roam over both IPv6 and IPv4 networks.

Implementing NAT-PT/SIIT, ALGs and consideration to the mobility support in NAT-PT environment

To deploy IPv6 we need some transition mechanisms that help existing IPv4 users move to IPv6 easily. NATPT (Network Address Translation - Protocol Translation, RFC-2766) is a transition mechanism which supports communication between the IPv6 node and 1Pv4 node by translating header of IP packet. NAT-PT uses IPv4/IPv6 header translation rules specified in SIIT (Stateless IP ICMP Translation, RFC-2765). Since NAT-PT is a technology based on NAT (Network Address Translation) it has the same characteristics as what NAT has. So it needs ALG (Application Layer Gateway) for a specific application layer protocol embedding IP address in its payload. Especially DNS-ALG is the most important thing than any other one. Because it discovers IPv6 address for IPv4 node from its IPv4 address. In this paper, we suggest effective DNS-ALG mechanism. MIPv6 (Mobile IPv6) is another hot issue in IP networking area. If NAT-PT is used in MIPv6 environment NAT-PT needs some modifications to guarantee seamless MIPv6 operation. We also suggest the issues regarding mobility support in NAT-PT environment.

Implementation of NAT-PT/SIIT, ALGs and consideration to the mobility support in NAT-PT environment

To deploy IPv6 we need some transition mechanisms that help existing IPv4 users move to IPv6 easily. NAT-PT (network address translation - protocol translation, RFC-2766) is a transition mechanism which supports communication between the IPv6 node and IPv4 node by translating the IP packet header. NAT-PT uses IPv4/IPv6 header translation rules specified in SIIT (stateless IP ICMP translation, RFC-2765). Since NAT-PT is a technology based on NAT (network address translation) it has the same characteristics as NAT. So it needs an ALG (application layer gateway) for a specific application layer protocol, embedding an IP address in its payload. Especially, the DNS-ALG is most important because it discovers the IPv6 address for the IPv4 node from its IPv4 address. We suggest an effective DNS-ALG mechanism. MIPv6 (mobile IPv6) is another hot issue in the IP networking area. If NAT-PT is used in an MIPv6 environment, NAT-PT needs some modifications to guarantee seamless MIPv6 operation. We also suggest the issues regarding mobility support in an NAT-PT environment.

ECU configuration framework based on AUTOSAR ECU configuration metamodel

AUTOSAR (AUTomotive Open System ARchitecture) is a partnership of automotive manufacturers and suppliers working together to develop and establish a de-facto open industry standard for automotive E/E architectures. AUTOSAR defines architecture, methodology, and application interfaces. The methodology describes ways to exchange formats or description templates to enable a seamless configuration process of the basic software stack and the integration of application software in ECUs and it includes even the methodology how to use this framework. The configuration process is comprised of several steps such as system configurations and ECU configuration. In ECU configuration step, many ECU configuration parameters based on system configuration results are organized into XML files. This paper describes methodology how these ECU configuration parameters are described, classified, and stored in XML files.

Scalable domain-based routing scheme for ICN.

Moving the focus from nodes to information objects raises scalability issues, therefore name-based routing and name resolution should be designed to scale accordingly. There are two types of naming scheme: hierarchical and flat namespace. To guarantee clean separation of identifier (name) from locator and scalability in routing, we chose flat name and designed domain-based routing. A significant requisite to be considered when flat name is chosen is an efficient name-resolution system (NRS). Bloomfilter-based NRS [9] is our proposal for this issue. Once a name is resolved into locator(s), discovery and delivery steps are carried out based on the routing scheme of locator. For scalability in routing of locator, network is projected into hierarchically-organized domain structure. A domain is a group of nodes or other domains. This composition could be physical or logical. Each domain has its own identifier, and the concatenation of domain IDs from top level domain to a certain domain which a node belongs to is a “locator” for that node. Each domain has one or more domain gateways. All traffic from/to the domain should pass through any of domain gateways. Routing information based on this type of locators is exchanged among domain gateways by using modified link-state routing protocol which can suppress LSA explosion. Thanks to this hierarchical domain structure, locators are highly aggregatable (which means scalable routing), and any node in heterogeneous network can communicate each other.

Implementation of prefix delegation mechanism using DHCPv6 protocol

IPv6 enables simple, automatic host configuration. Conversely, it does not provide any specification to automatically delegate a prefix to a router; to solve this problem several requirements were described and a solution using DHCPv6 protocol for those requirements was standardized. DHCPv6 protocol let DHCPv6 servers pass network configuration parameters to IPv6 nodes. DHCPv6 servers can pass IPv6 prefix delegation parameter to a requesting router by using IPv6 prefix option and requesting router which got the prefix from server can advertise prefix(es) derived from that prefix. To do this, we need DHCPv6 client/server supporting prefix delegation option and router advertisement daemon. In this paper, we implemented DHCPv6 client supporting IPv6 prefix option and for DHCPv6 server and router advertisement module we use open source project to test our s/w module.

Subband energy studies in intermixed GaAsAl0.35Ga0.65As multiple quantum wells

Abstract Photoluminescence (PL) measurements were performed in order to investigate the deformation of the GaAs Al 0.35 Ga 0.65 As multiple quantum wells (MQWs) due to thermal treatment. Rapid thermal annealing was performed at 950°C for 10, 20, and 30 s after the Si3N4 capping layer was evaporated on the sample. The PL spectra for the as-grown and annealed samples show the transitions from the 1 st electronic subband to the 1 st heavy hole (E1-HH1) and from the 2nd electronic subband to the 2nd heavy hole (E2-HH2), and the PL signals shift to the high-energy side as the annealing time increases. The potential profile of the quantum well as a function of the Al diffusion length was investigated, and subband energy levels in the GaAs Al 0.35 Ga 0.65 As MQMs were calculated by a variational method making use of the potential profile. The Al diffusion lengths for the annealed MQWs at 950°C for 10, 20, and 30 s determined from the (E1-HH1) PL peaks were 2.15, 4.45, and 6.3 nm, respectively. The behavior of the difference between the experimental values of (E2-HH2) and (E1-HH1) as a function of the Al diffusion length is in good agreement with theoretical results.