Christophe Jelger

Multicast for mobile hosts in IP networks: progress and challenges

In the past few years, multimedia applications have become very popular on the Internet, and a growing number of users have shown interest in this type of communications. IP multicasting has logically been considered to support such transmissions, mainly because its inherent nature is to efficiently minimize the bandwidth required to deliver multimedia data to a large set of targeted receivers. In the meantime, there has been a steady increase in the number of mobile wireless devices connected to the Internet. It has also clearly appeared that mobile Internet users will expect to have access to the services and applications available in traditional wired networks, and these services will surely include multimedia applications. Consequently, many efforts are being made to provide efficient mobility and multicasting support, and to bring the two together in the next generation of IP networks.

Supporting mobile SSM sources for IPv6

Mobile IPv6 (MIPv6), the IPv6 version of Mobile IP which is currently being developed by the Internet Engineering Task Force (IETF), is a protocol that describes how a mobile node can change its point of attachment to the Internet. While MIPv6 focuses on unicast communications, it also proposes two basic methods, known as bi-directional tunneling and remote subscription, to handle multicast communications with mobile nodes. In the mean time, the deployment of Source-Specific Multicast (SSM) is of great consideration, mainly for scalability reasons as it is a strong candidate that could be used to support inter-domain multicast routing. In the particular case of mobile IPv6 SSM sources, the mechanisms proposed in MIPv6 to support multicast communications introduce a number of problems that strongly degrade the SSM routing mode of operation. The intend of this document is to describe protocol enhancements that can be used to solve the problems introduced by mobile SSM sources when used with the current version of MIPv6. The extensions, mechanisms and mode of operation of the protocol proposed in this paper are denoted as MSSMSv6 (Mobile SSM Sources for IPv6).

Proactive address autoconfiguration and prefix continuity in IPv6 hybrid ad hoc networks

In ad hoc networks (MANETs), wireless nodes spontaneously collaborate to route packets among a multi-hop and versatile topology. While such networks have originaly been considered as autarkical systems, it becomes clear that there is a growing interest in connecting them to the Internet. In such a hybrid ad hoc network, one or more nodes act as gateways to the outside world. This situation requires the use of a global addressing scheme in order to allow end-to-end communications between MANET nodes and correspondents in the Internet. In this paper, we present and evaluate an IPv6 address autoconfiguration protocol based on the original concept of prefix continuity. This feature ensures that there exists, between a node N and its gateway G, a path of nodes such that all nodes on this path use the same IPv6 prefix than N and G. As a result, all the nodes of a given sub-network form a logical tree rooted at the sub- networks gateway, and in which all nodes share an identical IPv6 prefix. In a multiple-gateways and multiple-prefixes environment, our protocol proactively and dynamically reacts to topological changes in order to maintain the prefix continuity of each sub- network.

Virtual network stacks

In this paper, we get inspiration from peer to peer file sharing networks to provide a new way of inter-networking. In our proposal, nodes having access to multiple network types can share their networking resources with other peers residing in networks with different protocols and (potentially) different addressing schemes. Such neighbor nodes will form a peer to peer overlay backbone; the purpose of it being to offer to applications and protocols access to remote network stacks that their running hosts do not implement or have no direct access to. This creates RPC-like access to foreign network stacks well in line with a federation approach that avoids introducing a global overlay for integrating heterogeneous networks.

A System Architecture for Evolving Protocol Stacks (Invited Paper)

A majority of network architectures aim at solving specific shortcomings of the original Internet architecture. While providing solutions for the particular problems, they often lack in flexibility and do not provide general concepts for future networking requirements. In contrast, we introduce a network architecture that aims to be versatile enough to serve as a foundation for the future Internet. The main pillars of our architecture are communication pivots called information dispatch points (IDPs) which embed the concept of modularity at all levels of the architecture. IDPs completely decouple functional entities by means of indirection thus enabling evolving protocol stacks. Our architecture also provides a consistent application programming interface (API) to access node-local or network-wide functionality. In addition to the description of this architecture, we report about a working prototype of the architecture and we give examples of its application.

An "Autonomic Network Architecture" Research Project

ABSTRACT The goal of autonomic networking is to automate as much network maintenance related tasks as possible that beforehand required human intervention. The level at which the delegation of responsibilities can occur ranges from the configuration of address parameters to run-time protocol switching, it includes networking software upgrades and composition and even envisages the evolution of a complete network architecture as a whole. In this paper we describe the profile of the “Autonomic Network Architecture” project within EU FP6 that has prominent Swiss involvement and roots. We also briefly explain some of the “self-star” properties which are characteristic for research projects on autonomics.