Stefan Schmid

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Papers by Stefan Schmid

Policy routing architecture for IP flow mobility in 3GPP's Evolved Packet Core

2010 IEEE Globecom Workshops, 2010

The 3rd Generation Partnership Project is specifying solutions for IP flow mobility, which enable... more The 3rd Generation Partnership Project is specifying solutions for IP flow mobility, which enable IP data flows being routed between a mobile terminal and the infrastructure via a 3GPP and non-3GPP access systems, e.g. over LTE and WLAN. Connectivity via the different access systems is provided based on the concept of a shared single Packet Data Network connection. In order

QoS based Real Time Audio Streaming on IPv6 Networks

Live audio streaming is an important component of Internet multimedia. The currently deployed Int... more Live audio streaming is an important component of Internet multimedia. The currently deployed Internet oers poor support for such streams due to the lack of Quality of Service (QoS) capabilities. However, IPv6, the new Internet Protocol has now included provision for QoS. The introduction of a ow label in the protocol header is intended to enable classication of packets according to their destination and service. Reservation protocols such as RSVP (Resource ReSerVation Protocol) can make use of this stream identier to reserve resources for particular streams in the routers along the transport path. This paper explores the eectiveness of resource reservation in IPv6 networks for live audio streaming. An important area for investigation is whether there is an eciency gain due to the employment of low level ow labels. The paper summarizes the results of our extensive measurements and comparisons with currently deployed technologies. Specic attention is paid to the performance chara...

Improving RSVP for better support of Internet multimedia communications

Proceedings IEEE International Conference on Multimedia Computing and Systems

We have observed the failure of RSVP to be widely accepted as the solution to resource reservatio... more We have observed the failure of RSVP to be widely accepted as the solution to resource reservation in the Internet. Because we are convinced of the need for resource reservation, in at least parts of the Internet, to support multimedia communications, we have set about trying to improve RSVP. By careful study of the protocol, we have identified areas for improvement, and propose REDO RSVP, a reduced overhead version that includes a fast establishment mechanism (FEM). In this paper we describe the rationale for REDO RSVP and present an analysis of its features and operations.

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Mobile 4-in-6: a novel IPv4 / IPv6 transitioning mechanism for mobile hosts

IEEE Wireless Communications and Networking Conference, 2005

It is becoming increasingly apparent that the IETF mobile IPv6 protocol will have a role to play ... more It is becoming increasingly apparent that the IETF mobile IPv6 protocol will have a role to play in future mobile and wireless networks. However, it is extremely likely that even after a real world deployment of IPv6, a considerable number of &#39;legacy&#39; IPv4 applications and devices will remain in regular use for many years to come. Recently, much work has

Media Aware Overlay Routing in Ambient Networks

2005 IEEE 16th International Symposium on Personal, Indoor and Mobile Radio Communications

Abstract With the increasing heterogeneity of Internet enabled devices and Internet access techno... more

REDO RSVP: Efficient Signalling for Multimedia in the Internet

Lecture Notes in Computer Science, 1999

Alarming reports of performance and scalability problems associated with per-flow reservations ha... more Alarming reports of performance and scalability problems associated with per-flow reservations have led many to doubt the ultimate utility of RSVP and the Integrated Services Architecture that relies on it. Because we are convinced of the need for some form of resource reservation, to support multimedia communications in the Internet, we have set about trying to improve RSVP. By careful study of the protocol, we have identified areas for improvement, and propose REDO RSVP, a reduced overhead version that includes a fast establishment mechanism (FEM). In this paper we describe the rationale for REDO RSVP and present a detailed analysis of its features and operations. We also analyse REDO RSVP by means of simulations, and show that it offers improvements to the performance of RSVP.

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Voice Call Continuity - A Critical Step Towards All-IP Based Next Generation Networks

IEEE GLOBECOM 2008 - 2008 IEEE Global Telecommunications Conference, 2008

ABSTRACT The recent developments in the fixed and mobile telecommunication industry, namely the r... more ABSTRACT The recent developments in the fixed and mobile telecommunication industry, namely the rapid penetration of broadband access and new charging models in the broadband market in conjunction with the success of wireless local area networks and the general trend of fixed and mobile convergence, are transforming the telecommunication landscape. One of the main challenges is to integrate the fixed and mobile technologies in a way that leverages the strengths of different technologies and improves the service experience for the end user. A crucial step for this transformation is to provide adequate support for users to seamlessly switch between network domains and technologies. The main contribution of this paper is a solution that allows a mobile terminal to change from the mobile radio access to the fixed/cable access provided over a local wireless network or vice versa without disrupting an active ongoing voice call. The implementation of the proposed solution was tested and evaluated in an experimental network with real voice calls.

Local mobility and service access for enterprise femtocell networks

Transactions on Emerging Telecommunications Technologies, 2013

ABSTRACT

Scalability analysis of the TurfNet naming and routing architecture

Proceedings of the 1st ACM workshop on Dynamic interconnection of networks, 2005

TurfNet is a novel internetworking architecture that enables communication among autonomous and h... more TurfNet is a novel internetworking architecture that enables communication among autonomous and heterogeneous network domains. The architecture uses a global identity namespace and does not require global addressing or a shared internetworking protocol. It integrates the new concept of dynamic network composition with other recent architectural concepts, such as decoupling locators from identifiers. This paper examines whether TurfNet's naming and inter-domain routing architecture can scale to networks of the size of the global Internet. The paper uses existing research into the topology of the Internet's autonomous system graph and related results that quantify typical traffic patterns to analyze the scalability and performance of the TurfNet architecture on similar internetwork topologies.

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Scalability Analysis of the TurfNet Internetworking Architecture

IEEE GLOBECOM 2007-2007 IEEE Global Telecommunications Conference, 2007

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SoftEPC — Dynamic instantiation of mobile core network entities for efficient resource utilization

2013 IEEE International Conference on Communications (ICC), 2013

ABSTRACT Existing mobile network infrastructures, for example the Evolved Packet Core (EPC), are ... more ABSTRACT Existing mobile network infrastructures, for example the Evolved Packet Core (EPC), are based on mission specific, specialized network nodes/entities that are interconnect via standardized interfaces in a static manner, each providing a specific service/function. One common practice adopted by many Mobile Network Operators (MNOs) in order to cater to increasing traffic demand is the over provisioning of network and processing resources. However, this approach results in increased CAPEX and OPEX and in view of future load forecasts this approach is no longer considered feasible or economical. In this paper we address this specific issue and propose the concept of softEPC, which leverages the recent advances in cloud technology concept such as Infrastructure as a Service (IaaS) and virtualization techniques in the realm of mobile networks. A softEPC is considered as a virtual network of Evolved Packet Core (EPC) functions over a physical transport network topology. This will enable the on-demand and load-aware dynamic instantiation of network functions and services at appropriate locations in response to the actual traffic demand. The main objective of this approach is to increase the utilization of network resources by flexibly and dynamically placing the network functions/services where most appropriate to provide optimum service and where resources are available to increase the number of services provided to mobile users. The benefits and gains of this approach will be demonstrated by means of simulation results.

An Access Control Architecture for Metropolitan Area Wireless Networks

Lecture Notes in Computer Science, 2001

This paper introduces a novel access control architecture for publicly accessible, wireless netwo... more This paper introduces a novel access control architecture for publicly accessible, wireless networks. The architecture was designed to address the requirements obtained from a case study of ubiquitous Internet service provisioning within the city of Lancaster. The proposed access control mechanism is based on the concepts of secure user authentication, packet marking, and packet filtering at the access routers. The paper demonstrates to what extent this tokenbased, soft-state access control mechanism improves security and robustness, and offers improved performance over that provided by existing approaches within roaming networks. Early indications show the access control mechanism can better be implemented through the use of active routers, in order to facilitate dynamic rollout and configuration of the system. In addition, extensions to Mobile IPv6 are proposed, which provide support for roaming users at a fundamental level.

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Setup and Maintenance of Overlay Networks for Multimedia Services in Mobile Environments

Lecture Notes in Computer Science, 2005

A Service-specific Overlay Network (SSON) is a virtualization concept proposed for customized med... more A Service-specific Overlay Network (SSON) is a virtualization concept proposed for customized media delivery in the Ambient Networks architecture . The service specific media delivery network has to be constructed dynamically without prior knowledge of the underlying physical network. This process must consider unique properties, such as routing the media flow through strategic locations that provide special media processing capabilities (for example, media transcoding, caching and synchronization) inside the network. In today's dynamic and mobile network environments establishing an optimal SSON with a reasonable time and message/traffic complexity is challenging. This paper proposes a pattern-based methodology to establish the SSONs. This scheme enables setting up SSONs on demand without prior knowledge of the network topology and where the media processing capabilities are located in the underlying network. A new pattern referred to as path-directed search pattern is devised and applied to search for potential overlay nodes and to configure their media processing functions accordingly. The scheme is implemented on a pattern simulation tool and the result shows that SSONs of high quality can be built with a reasonable time and message/traffic complexity.

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Ambient networks in practice instant media services for users on the move

International Conference on Testbeds and Research Infrastructures for the Development of Networks and Communities, 2006

This demonstration exhibits the novel concepts of autonomic network composition and adaptive medi... more This demonstration exhibits the novel concepts of autonomic network composition and adaptive media delivery which have been developed as part of the EU framework 6 project ambient networks. A realistic use case serves as a demonstration scenario to illustrate how these core features of an ambient network work together in practice, and how they can contribute to improve the end

The autonomic network architecture (ANA)

IEEE Journal on Selected Areas in Communications, 2010

Abstract The objective of autonomic networking is to enable the autonomous formation and parametr... more

A highly flexible service composition framework for real-life networks

Computer Networks, 2006

ABSTRACT This article introduces a novel approach for service composition on active and programma... more ABSTRACT This article introduces a novel approach for service composition on active and programmable routers. The proposed composition framework enables flexible programmability of a router’s data path through dynamically loadable software components, called ‘active components’. The composition framework promotes transparent, dynamic and incremental deployment of network-side functionality which renders active network technologies capable of fully replacing the existing routing infrastructure by supporting all the legacy network protocols and services, and the integration of novel ones. On the other hand, the composition framework provides the necessary structures and mechanisms to deal with services composed by independent users potentially unaware of each other. The latter is particularly important as network routers are regarded as shared resources. In order to evaluate the proposed service composition framework, we have developed an implementation for the LARA++ active router architecture [S. Schmid, A component-based active router architecture, Ph.D. Thesis, Lancaster University, UK, November 2002] and deployed several of these active routers in a real-world service network. The evaluation demonstrates the flexibility of the composition framework by enabling the alteration of service composites at run-time and provides scalability in the generation of such composites by users or administrators. This work also reports on lessons learned while deploying several active services in a production network. Besides a qualitative evaluation of the service composition framework and the LARA++ architecture, we provide a number of quantitative results, which show that the overhead of our composition model does not adversely affect the performance of the router, despite the increased flexibility achieved.

A performance study of RSVP with proposed extensions

Computer Communications, 2002

Resource ReSerVation Protocol (RSVP) was developed as an intended key component for the evolving ... more Resource ReSerVation Protocol (RSVP) was developed as an intended key component for the evolving Internet, and in particular for the Integrated Services architecture. Therefore, RSVP performance is crucially important; yet this has been little studied up till now. In this paper, we target two of the most important aspects of RSVP: its ability to establish flows and its steady-state overhead. We first identify the factors influencing the performance of the protocol by modelling the establishment mechanism. Then, we propose the principles of a Fast Establishment Mechanism (FEM) aimed at speeding up the set-up procedure in RSVP. We analyse FEM by means of simulation, and show that it offers improvements to the performance of RSVP over a range of likely circumstances. We also present the principles of a simple mechanism aimed at reducing the steady-state (i.e. refresh) message overhead of RSVP.

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Method for Supporting Network Based Mobility for a Mobile Terminal in an Ims (Ip Multimedia Subsystem) Architecture

An experimental study of novel ambient network concepts

A new networking architecture referred to as Ambient Networks is currently under investigation, w... more A new networking architecture referred to as Ambient Networks is currently under investigation, which aims at enabling the cooperation of heterogeneous networks belonging to different operator and/or technology domains. Key elements of the Ambient Networks concepts are the Ambient Control Space (ACS) encompassing all control functions in a certain network domain and the concept of composition of networks sharing network

Mobile communication system for matching resource amount of core network bearer and resource amount of visited network bearer

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