Koert Vlaeminck

Deployment of service aware access networks through IPv6

Substantial research effort is currently devoted to the development of a future, low-cost access and edge network, enabling the delivery of broadband multimedia services to subscribers. As the world is moving away from current ATM (Asynchronous Transfer Mode) and PPP (Point-to-Point Protocol) access network architectures for a number of reasons, including lack of Quality of service (QoS) and autoconfiguration support, this paper presents how IPv6 can fill the hole that ATM and PPP leave behind in a very convenient, packet-oriented way. The described architecture allows multiple edge nodes to be present, increasing robustness in case of edge node failure, but also increasing scalability as non-local traffic can be balanced across multiple edge nodes. The ability to process local traffic without edge involvement further increases scalability, due to the growing peer-to-peer traffic volume. Since the architecture is independent of the under- lying layer-2 technology used for the aggregation network, a phased and smooth migration from ATM to Ethernet equipment, which is claimed cheaper and easier to maintain, is possible. For some selected broadband access topologies, an efficient IPv6 subnetting scheme, minimizing routing tables through hierarchical addressing, is introduced and evaluated. Solutions for forcing non-local traffic to the correct ISP edge, in a multi-ISP environment, are presented. Finally, the deployment of the described architecture in an actual IPv6 test bed is discussed.

Modeling the performance of a NAT/firewall network service for the IXP2400

The evolution towards IP-aware access networks creates the possibility (and, indeed, the desirability) of additional network services, like firewalling or NAT, integrated into the network devices. These new services, however, force the network components to be both flexible (to cope with changing protocols and applications) and powerful. Network processors as a platform on which to implement the network services seem to fit the bill.System performance should be assured by incorporating performance analysis into the design of the system, by means of performance modeling at the architectural design stage. This paper describes the use of Software Performance Engineering during the design of a firewall/NAT router on the Intel IXP2400 network processor. Several design options were first modeled and analysed, and based on those simulations, a final design was chosen and implemented.

Towards transparent personal content storage in multi-service access networks

Anytime, anywhere and anyhow access to personalized services requires the complete decoupling of devices for accessing the service and the supporting personal data storage. When deploying such transparent personalized services, an important question that needs answering is where to install the storage servers. In this respect, this paper considers the deployment of a personal content storage service in multi-service access networks. The storage server placement problem is formulated as a binary integer linear programming (BILP) problem and a heuristic storage server placement algorithm (SSPA) is presented and evaluated. First it is assumed that servers do not fail. Consequently, the problem formulation is extended to include replication and striping and both BILP and heuristic methods are modified to cope with the additional constraints. The extended SSPA heuristic is used to analyze several resilience and striping scenarios. It is shown that the SSPA produces close to optimal results and is very efficient for optimizing server placement in personal content storage deployments.

Deploying Digital Media Libraries in Multi-Service Access Networks

A current important trend is the introduction of new services in the access and aggregation network, close to the end user. A major opportunity for such service enabled access networks is providing users with fast and reliable storage, allowing them to transparently access and share their digital media library anytime, anywhere, while guaranteeing data retention. An important issue in deploying such a service is where to put the storage servers, in order to minimize deployment cost without sacrificing performance. This paper presents and evaluates two algorithms for solving the storage server placement problem, minimizing the deployment cost while guaranteeing a low delay for accessing the digital media libraries from any access node. The base algorithm, referred to as SSPA (storage server placement algorithm), assumes the access and aggregation network has unlimited bandwidth. SSPA provides a lower bound on the required number of servers, respecting a maximum delay constraint. The extended algorithm, SSPA, solves the storage server placement problem, respecting both a maximum delay constraint and bandwidth constraints of the network links. It will be shown that the algorithms produce close to optimal results relatively fast

Design and implementation of an application server load balancing architecture supporting the end-to-end provisioning of value-added services

Service providers can offer a wide variety of value added services, such as managed home networking, home-automation and security management, multimedia multiparty conferencing and content delivery. Very often hard- and software from different vendors are used to implement these services. In most cases, multiple application servers need to be deployed for each service in order to balance the load of the service sessions. We describe an architecture that offers automatic load balancing of service sessions over the available application servers, abstracting from the actual type of the service and its implementation by translating the service and vendor specific request formats into an internal XML format. The load balancing of the service sessions is done taking into account the capabilities of each application server (which service(s) does it implement), its load, and the location of running sessions (a request to join an active session has to be forwarded to the application server running the session). Furthermore, scalability is ensured by organizing the application servers into pools. New application servers can easily be added.