Hosik Cho

Route Optimization Using Tree Information Option for Nested Mobile Networks

Mobile IP is the basic solution to provide host mobility, whereas network mobility refers to the concept of collective mobility of a set of nodes. In the simplest scenario, a mobile network moves as a single unit with one mobile router (MR) that connects it to the global Internet. Also, multiple mobile networks can be nested in a hierarchical form, e.g., a wireless personal area network (PAN) in a vehicular network. In a nested mobile network, multiple MRs form a tree hierarchy in which the root MR is called the top-level mobile router (TLMR). Nested mobile networks exhibit the pinball routing problem, which becomes worse in proportion to the number of nested levels in the hierarchy. To solve this problem, we propose a routing optimization scheme using a tree information option (ROTIO) that extends the NEMO basic support protocol. In the ROTIO scheme, each MR in the nested mobile network sends two binding updates (BUs): one to its home agent and the other to the TLMR. The former BU contains the TLMRs home address, while the latter contains routing information between the issuing MR and the TLMR. This alleviates the pinball routing problem significantly. Now, a packet from a correspondent node only needs to visit two transit nodes (the home agents of the MR and the TLMR), regardless of the degree of nesting. Moreover, the ROTIO scheme provides location privacy and mobility transparency. We also extend ROTIO to perform routing between two mobile network nodes inside the same nested mobile network more efficiently and to substantially reduce the disruption when a mobile network hands off

Load sharing and session preservation with multiple mobile routers for large scale network mobility

By means of network mobility (NEMO) support, users can organize their various communication devices into a network, called a mobile network. In a mobile network, the mobile router provides the connectivity to the Internet and mobility management transparency for the rest of the mobile nodes in the mobile network. So, it is important for the mobile router to assure reliable communications and a high data rate for the group of nodes behind it. In support of broadband wireless communications, the use of multiple mobile routers would allow the transfer of large volumes of data to a group of mobile nodes. This paper addresses the protocol issues arising from the use of multiple mobile routers, and analyzes the influence of mobility on load sharing and session preservation when there are multiple mobile routers. Simulation results with different configurations show that session preservation and load sharing schemes are influenced by application mobility behavior and wireless access technologies.

RBU+: Recursive Binding Update for end-to-end route optimization in nested mobile networks

In this paper, we propose an end-to-end route optimization scheme for nested mobile networks, which we refer to as Recursive Binding Update plus (RBU+). A nested mobile network is a hierarchical form of mobile networks. Nested mobile networks suffer from a pinball routing problem with hierarchical mobile routers. This problem becomes more serious in the case of macro mobility, as the routing distance becomes longer. To solve the pinball routing problem of nested mobile networks, in this paper we propose the Recursive Binding Update (RBU) and three distinct solutions for the end-to-end routing in mobile networks using the method of obtaining the route from the Top Level Mobile Router (TLMR) to the destination Mobile Network Node (MNN). The solutions for end-to-end routing include source routing, Table Driven Forwarding (TDF), and Route Request Broadcast (RRB). From the results of the simulations, it was shown that RBU+RRB presents the best performances among the different solutions. When combined with an end-to-end routing capability, RBU+ provides optimal routing in nested mobile networks. RBU+ reduces the pinball routing cost, and this reduction becomes more significant as the degree of nesting becomes higher and the distance between the home agents of the mobile router and its parent/child mobile routers becomes longer. When combined with an appropriate reverse route optimization scheme, the routing costs are independent of the degree of nesting and the distance between the Home Agents (HAs).

R-BU: recursive binding update for route optimization in nested mobile networks

This paper proposes recursive binding update (R-BU) that optimizes routing for nested mobile networks. Nested mobile network is a hierarchical form of mobile networks, e.g. a wireless personal area network (PAN) in a vehicular network. A mobile network moves as a single unit with one or more mobile routers that connect it to the global Internet. Nested mobile networks have pinball routing problem with hierarchical mobile routers. This problem becomes more serious in the case of macro mobility as the routing distance becomes longer. To solve the pinball routing problem of nested mobile networks, we propose routing optimization scheme called R-BU based on recursive binding update. R-BU maintains optimal route to the destination by updating its binding recursively. R-BU requires no changes in existing mobile IP except binding update operation. By using R-BU, correspondent nodes can maintain optimal route to their destinations after some convergent time. R-BU reduces pinball routing cost and the reduction is more useful as the degree of nesting becomes deeper and the distance between the home agents of a mobile router and its parent/child mobile routers becomes longer.

Load sharing and session preservation with multiple mobile routers for large scale mobile networks

By means of NEtwork MObility (NEMO) support, users can organise their various communication devices into a subnet called mobile network. The Mobile Router (MR) provides the connectivity to the internet and mobility management transparency for the rest of the mobile nodes in the mobile network. So, the MR must assure reliable communications and a high data rate for the group of nodes behind it. In support of broadband wireless communications, the use of multiple MRs would allow the transfer of large volumes of data to a group of mobile nodes. This paper addresses the protocol issues arising from the use of multiple MRs, and analyses the influence of mobility patterns on load sharing and session preservation. Then, two mobility-aware selection schemes are proposed, which select a MR. Firstly, the best-connected MR selection scheme is designed for regular mobility and is based on the fact that the most recently updated binding remains effective for the longest period of time. It preserves the connection from the mobile network to the internet whether the accessible area is continuous or not, and this even in a fast handoff environment. Secondly, the most-beneficial MR selection scheme is designed for random mobility. The simulation results show that the performance varies depending on the hardware configuration. Based on these results, it was found that application-awareness is critical to achieve good performance.

Mobility-Aware Mobile Router Selection and Address Management for IPv6 Network Mobility

Network mobility (NEMO) extends IP mobility to moving networks, which are groups of nodes that often constitute a subnet of a mobile router (MR). To realize this collective mobility, there are a number of important issues such as addressing and multihoming. With the proliferation of mobile nodes connected to the Internet, the efficient allocation/deallocation of addresses is becoming a vital requirement. We propose a collaborative address management scheme for network mobility, where the home DHCPv6 agent of a mobile network performs prefix delegation, while the mobile DHCPv6 agent (in the mobile network) allocates the IPv6 address to each mobile node. Also, network mobility with multiple MRs is taken into consideration. To provide a mobile network that has multiple MRs with robust Internet connectivity, we propose mobility-aware mobile router selection schemes. The concept of “mobility awareness” refers to the capability of a moving network in a vehicle (e.g., a train) to pinpoint the most stable Internet connectivity, by choosing the mobile router based on the vehicle’s movement pattern. The simulation shows that the proposed scheme outperforms a round-robin mobile router selection scheme in terms of the amount of carried traffic.

HCP6: a high-quality conferencing platform based on IPv6 multicast

We introduce a high-quality videoconferencing application implemented using IPv6 multicast. The conferencing application is made to operate at IPv6 network environment on Microsoft Windows XP or 2000 enabled IPv6 stack. We implement this application using MPEG-4, MJPEG and Video-1 codec to support high-quality conference and can select one by necessity of usability. In this paper, we describe the software architecture that is divided three managements area, efficient buffer managements that is data transmission technique from Directshow filter to network manager, RTP and RTCP library, and DirectShow technology that is provided by Microsoft DirectX. And we present the experimental result that measures delay of a respective module and bandwidth of this application.

The Implementation of Layer-three Site Multihoming Protocol (L3SHIM)

Layer-three SHIM (L3SHIM) protocol is designed to support site multihoming in IPv6 network and now being standardized at SHIM6 working group in IETF. A host or router can have more than two egress interfaces which are connected to a different ISP and configured by distinct IPv6 network prefixes. By using L3SHIM, when an interface is down, another interface can backup for the ongoing connections as it adopts identifier/locator decoupling architecture. Our team is implementing the L3SHIM protocol on Linux based PC using netfilter hooks in the network kernel. We implemented L3SHIM core and REAP component, and verified the feasibility and usefulness of L3SHIM in multi-homed environment by an experiment. We reported the implementation progress to SHIM6 working group in IETF 67th meeting.

Extended peer-to-peer protocol based on IPv6

This paper proposes extended peer-to-peer (P2P) protocol based on IPv6. There are a lot of works on structured P2P protocols using distributed hash table (DHT). Especially, our P2P algorithm and implementation are focused on the efficiency and the scalability for maintaining the P2P overlay network. To achieve efficient routing, we merge the P2P overlay with the messenger service. With friend nodes as finger, a query can routed through more efficient path on the P2P overlay network. We implemented extended P2P protocol for messenger and multimedia services (MMP2P) on Microsoft Windows environment and evaluated the performance of our proposal