IP-based Networks Research Articles

Web-based fax server for home or small business use

Applying IP and Web technologies and the inherent properties of a broadband router widely used at home or in small business, this paper presents a paperless, sharable, plug-and-play, Web-based fax server for multiple users. Instead of using email via a digital network as FoIP, the proposed fax server sends and receives fax documents via the public switched telephone network like the conventional analog fax machines do. The fax server users handle incoming and outgoing faxes by only Web browsers through an IP-based local area network composed of an off-the-shelf broadband router, the proposed fax server, and the users' computers. This paper introduces the system architecture and software driving techniques of the proposed fax server.

Using P2P, GRID and Agent technologies for the development of content distribution networks

Content Distribution Networks (CDNs) have recently emerged as an innovative technology to improve the efficiency of static, time-dependent, and rich media content delivery atop large-scale IP-based networks. Apart from network technology advances, the design and implementation of robust and efficient CDNs in large-scale computing environments call for paradigms and software technologies which are able to support the core functionalities of CDNs, namely distribution, management, discovery, and delivery of content. Agent, GRID, and P2P computing paradigms and technologies have already demonstrated their suitability in supporting the development of high-performance systems over large-scale, dynamic, and heterogeneous environments. Therefore the combined use of all three paradigms and technologies which are characterized by dynamism, robustness, and intelligence, is expected to increase the effectiveness and boost the efficiency of future CDNs. In this paper, we present UPGRADE-CDN, an experimental component-based platform which jointly uses P2P, GRID, and Agent based mechanisms for client request redirection, CDN monitoring, and content delivery.

A quality-of-service signaling architecture for seamless handover support in next generation, IP-based mobile networks

The coupling of signaling protocols for mobility management and resource reservation plays an important role to achieve Quality-of-Service (QoS) in wireless environments. When performing a handover, request and allocation of resources have to be done in the shortest possible time to avoid disruptions for the user service. Therefore, it is preferable to ensure resource availability in advance, which we call anticipated handover. This approach for providing seamless handovers in turn poses challenges for the overall design of the QoS architecture and its associated QoS signaling protocol. This article describes the design, implementation, and evaluation of a comprehensive QoS architecture and a suitable QoS signaling protocol. It discusses intrinsic problems of reservations in IP based networks such as session ownership as well as a number of protocol design issues regarding the integration of QoS signaling with other protocols, such as Mobile IP. In particular, we define an end-to-end QoS architecture and a mobility-aware reservation signaling protocol Mobility Aware Reservation Signaling Protocol (MARSP) that supports anticipated handover, thus enabling seamless services over heterogeneous wireless access networks. The presented architecture and protocol were implemented and evaluated by measurements. They show that anticipated handovers not only outperform hard handovers regarding handover latency, but that they also provide functional and robustness advantages.

A Novel Onboard-gateway-based Mechanism to Improve TCP Performance in Aeronautical Satellite Networks

AbstractThe IP-based networks on aircraft serve to support Internet services via satellites. However, in aeronautical satellite hybrid networks, the TCP protocol performance often deteriorates due to improper decreases and slow recovery of the congestion window. This paper proposes a window size determination and notification mechanism, onboard-gateway-based mechanism (OGBM), which is based on the onboard gateway in the networks on aircraft. A cross-layer approach is adopted by the onboard gateway to obtain the satellite link bandwidth information. And then, by the gateway, through changing the receiver's advertised window field in ACK packets, TCP sources are notified of the window size of each TCP source calculated on the ground of bandwidth delay product and flow numbers. The mechanism is able to avoid improper changes of TCP window and serve multiple users. Simulation results show that the mechanism with the fairness index close to 1 improves TCP performance in aeronautical satellite networks.

Seamless handover support over heterogeneous networks using FMIPv6 with definitive L2 triggers

Various wireless communication systems have been developed and will be integrated into an IP-based network to offer end users the Internet access anytime and anywhere. In heterogeneous multi-access networks, one of main issues is to manage nodes' mobility with session continuity and minimal handover latency. In order to support the mobility of mobile nodes, MIPv6 has been proposed by IETF. Even though MIPv6 provides a solution to handling nodes' mobility in IPv6 networks, there is a significant problem due to its inability to support a seamless handover caused by long latency and high packet losses during a handover. FMIPv6 has been proposed to reduce MIPv6 handover latency by using an address pre- configuration method with the aid of L2 triggers. Current research defines a general L2 trigger model for seamless handover operation, but it does not address the exact timing and definitive criteria of L2 triggers which causes a significant effect on the handover performance of FMIPv6. This paper considers the available timing and accurate criteria of L2 triggers. With the definitive L2 triggers, we present a practical handover scenario to integrate L2 and L3 layers for low handover latency and low number of packet losses during a handover. We also study the impact of definitive L2 triggers on the handover performance of the FMIPv6 protocol in real testbeds and prove that the FMIPv6 protocol performs its handover operation prior to the L2 handover and obtains a seamless handover.

Location Area Design Algorithms for Minimizing Signalling Costs in Mobile Networks

In the next generation, IP-based mobile networks, one of the most important QoS parameters, are the delay and the delay variation. The cell handover causes incremental signalling traffic, which can be critical from the point of view of delay variation. It worsens the quality param-eters of the real-time services, which are the backbone of next generation mobile commercial services. We have designed and implemented two algorithms: a location area forming algo-rithm (LAFA) and a cell regrouping algorithm (CEREAL), which can help us to guarantee QoS parameters in the next generation mobile networks. We used our realistic mobile environment simulator to generate input statistics on cell changes and incoming calls for our algorithms and by comparing the values of the cost functions proposed by us, we recognized that significant reduction was achieved in the amount of the signalling traffic; the location update cost was decreased by 40-60% in average.

Simultaneous Mobility

To realize the full potential of mobile multimedia, mobility protocols are needed to handle situations when nodes move while in a multimedia session. Many mobility protocols have been proposed for IP-based networks. In some important cases in using these mobility protocols such as mobile IPv6 with route optimization, a problem can arise when both nodes are mobile and move simultaneously. The problem is that both sides’ binding updates could be lost. A few solutions have recently been proposed. A crucial indicator of the importance of the simultaneous mobility problem, and of its solutions, is the probability of its occurrence. However, previous articles have used only a simple analytical model to estimate the probability of the simultaneous mobility problem occurring. In this article, we present new and more accurate results on the variation of this probability with a number of critical variables.

Layer 3 VPN Services over IPv6 Backbone Networks: Requirements, Technology, and Standardization Efforts

Layer 3 virtual private networks (L3VFN) enable organizations to connect geographically dispersed sites to one another across the packet switched network of a service provider. The most popular form of L3VPN is based on BGP/MPLS (border gateway protocol/multiprotocol label switching) technology in which the service provider offers a network-based IP VPN routing and forwarding service to its customers across its own IPv4-based MPLS backbone network. With the deployment of IPv6-based backbone networks underway, there is an emerging requirement to support these same L3VPN services across a native IPv6 backbone network. This introduces a requirement to provide routing and tunneling of IPv6 VPN (and IPv4 VPN) packets across an IPv6 backbone network. Softwires is an Internet Engineering Task Force (IETF) Working Group chartered to address the requirement of providing a generalized, network-based, multi-address family, IP routing and tunneling capability across native IP backbone networks pursuant to IPv6 transitions. Elements of the softwires work can form the basis of an L3VPN over IPv6 solution. After providing a brief overview of how L3VPN works in various topologies, this article presents the requirements for L3VPN services over an IPv6 backbone network and discusses a possible solution set that builds over the softwire technology and related IETF standards. Finally, we outline future directions and how the softwire technology can support new services and improved scalability

Making SIP Make Cents

The Session Initiation Protocol (SIP) is used to set up realtime sessions in IP-based networks. These sessions might be for audio, video, or IM communications, or they might be used to relay presence information. SIP service providers are mainly focused on providing a service that copies that provided by the PSTN (public switched telephone network) or the PLMN (public land mobile network) to the Internet-based environment.

Grids in a Mobile World: Akogrimo's Network and Business Views

The use of wireless networking technologies has emerged over recent years in many application domains. The area of grids determines a potentially huge application domain, since the typical centralized computing centers require access from anywhere, e.g., from field engineers who are situated in a wireless network domain. Thus, the integration of suitable business views on mobile grids, of grid views on available technologies, and network views in a fully IP-based network domain determines the key challenge. The Akogrimo project's architecture developed, is outlined and discussed in this paper and provides the major details required to offer a fully integrated and interoperable solution for those three views of concern.

Utilizing Cross-Layer Information to Improve Performance in JPEG2000 Decoding

We focus on wireless multimedia communication and investigate how cross-layer information can be used to improve performance at the application layer, using JPEG2000 as an example. The cross-layer information is in the form of soft information from the physical layer. The soft information, which is supplied by a soft decision demodulator, yields reliability measures for the received bits and is fed into two soft input iterative JPEG2000 image decoders. When errors are detected with the error detecting mechanisms in JPEG2000, the decoders utilize the soft information to point out likely transmission errors. Hence, the decoders can correct errors and increase the image quality without making time-consuming retransmissions. We believe that the proposed decoding method utilizing soft information is suitable for a general IP-based network and that it keeps the principles of a layered structure of the protocol stack intact. Further, experimental results with images transmitted over a simulated wireless channel show that a simple decoding algorithm that utilizes soft information can give high gains in image quality compared to the standard hard-decision decoding.

TLMM: MIP-based Three Level Mobility Model

This article describes a Three Level Mobility Model (TLMM) for next generation wireless IP-based networks. TLMM is modular and straightforward as it leverages existing protocols, such as Mobile IPv4 as global mobility management and TeleMIP for intradomain mobility management for locating roaming nodes. It uses three dynamically autoconfigured care-of-addresses (CoAs) for routing the packets destined to mobile nodes. A Gateway Mobility Agent at the boundary of two domains provides a global CoA and identifies a mobile node’s attachment to the current domain. A regional CoA provides the specific area of the mobile node’s attachment within the domain, while a local CoA changes every time the mobile changes subnets and identifies the mobile’s attachment to the subnet level granularity. A dynamic handoff policy for supporting fast and seamless handoff reduces latency at a mobile node and minimizes packet loss. Simulation results using ns-2 supports our model. A detailed analytical framework for dynamic handoff has been presented in depth to estimate handoff initiation instance for reducing the probability of false handoffs.

DIP-MIP: Distributed individual paging extension for mobile IP in IP-based cellular networks

The mobility-enabling protocol Mobile IP supports location registration but not paging. However, current cellular networks use registration as well as paging procedures to minimize signaling cost. Accordingly, an extension to Mobile IP using distributed individual paging, the so-called DIP-MIP, is proposed. In DIP-MIP, each mobile host derives its own paging area size by optimizing a signaling cost function based on its individual mobility pattern. The cost function itself may use either of two mobility models – fluid flow and random walk – and the performance of DIP-MIP is analyzed for both. The impact of various parameters on the DIP-MIP signaling cost is studied as well. The performance of DIP-MIP is shown to be superior to that of Mobile IP (MIP) in reducing signaling load, managing mobility and supporting a large number of mobile users in IP-based cellular networks.

Key Exchange Protocol Supporting Mobility and Multihoming

In this work, a new key exchange protocol for IP-based mobile networks is introduced. This protocol is called KEPSOM ( Key Exchange Protocol Supporting M obility and Multihoming). The goals of designing KEPSOM are to develop key exchange protocol proposal characterized by its secrecy, simplicity, efficiency, resistivity, and its ability to support mobility and multihoming. The protocol requires only two roundtrips. The design limits the private information revealed by the initiator. An old security association (SA) can be replaced with a new one by rekeying without the need of restarting the protocol with a new session. On the other hand, the changes in IP address due to mobility or multihoming need not to restart the protocol with a new SA session. The proposed protocol can also support key exchange in hybrid wireless network, in which the mobile node can operate in both Ad Hoc and Base Station-oriented wireless network environments using different transmission modes. KEPSOM has been analyzed and proven secure. Several tests have been done to measure and evaluate the performance of the protocol. In these tests, it is found that the required time for rekeying is about 27% of the total required time for exchanging the keys. And the required time to detect and update the change in IP address, which may occur due to mobility or multihoming, is less than 10% of the total required time to establish a new SA sessions.

Differentiated service delivery in cooperative IP-based broadcast and mobile telecommunications networks

Differentiated service delivery in cooperative IP-based broadcast and mobile telecommunications networks

Mutual Complementarity between Diffusion-Type Flow Control and TCP

SUMMARY In current IP-based networks, the application of windowbased end-to-end flow control, including TCP, to ensure reliable flows is an essential factor. However, since such a flow control is provided by the end hosts, end-to-end control cannot be applied to decision-making in a time-scale shorter than the round-trip delay. We have previously proposed ad iffusion-type flow control mechanism to realize the extremely time sensitive flow control that is required for high-speed networks. In this mechanism, each network node manages its own traffic only on the basis of the local information directly available to it, by using predetermined rules. The implementation of decision-making at each node can lead to optimal performance for the whole network. Our previous studies showed that the mechanism works well, by itself, in high-speed networks. However, to apply this mechanism to actual networks, it needs to be able to coexist with other existing protocols. In this paper, we investigate the performance of diffusion-type flow control coexisting with TCP. We show that diffusiontype flow control can coexist with TCP and the two can be complementary. Then, we show that a combination of both controls achieves higher network performance than TCP alone in high-speed networks.

MCIP: A 3G/IP Interworking System Supporting Inter-Cluster Soft Handoff

In this paper, a novel 3-tier Mobile Cellular IP (MCIP) access network is proposed for interworking between a third generation (3G) wireless cellular system and a wireline Internet Protocol (IP) based network. An inter-cluster hard handoff scheme and an inter-cluster soft handoff scheme are proposed, based on the 3-tier MCIP system model, the core network protocol stacks, and the underlying MCIP routing algorithm. The core network protocol stack is presented to integrate the 3G radio interface and the IP-based core network, and to provide the access network with capability to support soft handoff macroscopic space diversity. The MCIP hard and soft handoff schemes are compared with the hard handoff schemes used in the Cellular IP and HAWAII access networks. The MCIP access network is more efficient in terms of signaling cost, but has the same scalability as Cellular IP and HAWAII. Both MCIP hard and soft handoff schemes enable IP packets to be delivered within the MCIP access network in-order without loss and duplication, a highly desired attribute for real-time multimedia applications. The advantages of supporting soft handoffs and quality-of-service (QoS) provisioning for real-time services are achieved at slightly increased system complexity.

Interactive TV: A new application for mobile computing

This contribution presents some recent developments in the field of interactive digital television and discusses the challenges of bringing these TV services to mobile devices. The paper addresses two different scenarios. The first part discusses the use case of complementing the TV set by mobile devices in a home network, considering also the aspect of using different networks (both broadcast and IP-based data networks) to deliver the content to the home. In the second part, the new field of mobile broadcast technologies is introduced and an overview over the different technologies and standardisation activities is provided.

Performance Study of Mobility Management Schemes in IP-Based Networks

Remarkable advances in mobile technologies and wireless communications allow users to access the Internet anywhere at any time. It becomes increasingly essential to support mobility in IP-based networks. The mobile IP is the most widely known mobility management scheme in IP networks. However, some inherent weaknesses of this protocol are only partially solved. Although the route optimization tries to figure out these problems, it cannot manage mobility binding efficiently. In this article, four binding refreshment schemes, including the always-push scheme, the on-demand scheme, the threshold scheme, and the adaptive push scheme, are proposed and evaluated. Among others, the adaptive push scheme is compared with the well-known mobile IP and route optimization. The simulation results show that the adaptive push scheme proposed in this article outperforms the others and significantly reduces the cost of mobility management in IP-based networks.

Cross‐layer protocols for satellite communication networks: part I

Cross‐layer protocols for satellite communication networks: part I