Lars Westberg

Resource Management in Diffserv (RMD): A Functionality and Performance Behavior Overview

The flexibility and the wide deployment of IP technologies have driven the development of IP-based solutions for wireless networks, like IP-based Radio Access Networks (RAN). These networks have different characteristics when compared to traditional IP networks, imposing very strict requirements on Quality of Service (QoS) solutions, such as fast dynamic resource reservation, simplicity, scalability, low cost, severe congestion handling and easy implementation. A new QoS framework, called Resource Management in Differentiated Services (RMD), aims to satisfy these requirements. RMD has been introduced in recent publications. It extends the IETF Differentiated Services (Diffserv) architecture with new admission control and resource reservation concepts in a scalable way. This paper gives an overview of the RMD functionality and its performance behavior. Furthermore, it shows that the mean processing delay of RMD signaling reservation messages is more than 1330 times smaller then the mean processing delay of RSVP signaling reservation messages.

On the effects of caching in access aggregation networks

All forecasts of Internet traffic point at a substantial growth over the next few years. From a network operator perspective, efficient in-network caching of data is and will be a key component in trying to cope with and profit from this increasing demand. One problem, however, is to evaluate the performance of different caching policies as the number of available data items as well as the distribution networks grows very large. In this work, we develop an analytical model of an aggregation access network receiving a continuous flow of requests from external clients. We provide exact analytical solutions for cache hit rates, data availability and more. This enables us to provide guidelines and rules of thumb for operators and Information-Centric Network designers. Finally, we apply our analytical results to a real VoD trace from a network operator and show that substantial bandwidth savings can be expected when using in-network caching in a realistic setting.

Fast Failure Handling in Ethernet Networks

Ethernet is becoming increasingly popular in metro and carrier-grade networks because of its cost-effectiveness, simplicity and scalability. Nevertheless, Ethernet was originally designed as a LAN technology, therefore, it lacks some features, such as fast fault-protection and sophisticated management, which are very important in the new carrier-grade application areas. We propose a simple failure protection mechanism for Ethernet networks that can recover from node and link failures under 50 milliseconds, which is also provided by SDH/Sonet rings. The mechanism relies on a lightweight distributed protocol that runs on IP routers at the edges of the network and works with commodity off-the-shelf Ethernet switches. This paper describes the protocol design and implementation as well as the network testbed implementation for assessing the performance and the robustness of the mechanism. The results collected in the testbed are shown and discussed in the paper.

Optimised local caching in cellular mobile networks

Motivated by the problem of increasing backhaul transmission costs in cellular mobile networks we examine the potential of highly distributed caching solutions. In particular we propose to overcome the problem of poor hit ratios in such solutions by forming caching domains which support pooling (the ability to fetch content from other caches when necessary) and equalisation (active transfers between caches to preload popular content). The characteristics of such a scheme are investigated by applying a new analytical model to a set of realistic examples. The model is verified against both computer based simulations and measurements in a real network, and it is found that the proposed scheme can reduce backhaul bandwidth requirements for an average cell inside a domain by a factor of 7 for web-like traffic and by a factor of 45 for video-like traffic, while the corresponding factors outside a domain amount to 41 and 997 respectively.

A reference architecture for micro-mobility support in IP networks

This paper presents an architecture for supporting micro-mobility in IP networks. The architecture is presented in terms of its functional blocks and interaction protocols. The architecture, named mobility plane architecture (MPA), offers a network-centric solution for micro-mobility. This means that all the functions necessary for supporting Layer-3 mobility are placed on the network, not on the mobile node. The architecture does not interfere with services already deployed in the transport network, even services supporting macro mobility such as Mobile IP. Another key point is the total independence of the architecture from IPv6, meaning that it can be deployed on existing IPv4 networks.

MPA: A Network-Centric Architecture for Micro-Mobility Support in IP and MPLS Networks

Micro-mobility protocols aim to improve localized mobility by reducing the handover overheads. In this paper we present the Mobility Plane Architecture (MPA). This architecture was designed to support micro-mobility in standard IP or MPLS/GMPLS networks in a network-centric way, that is, the burden demanded by micro-mobility is placed on the network, not on the mobile nodes. The main advantages of this architecture are its independence of IPv6 and the absence of new protocols for supporting L3 mobility.

QoS signaling across heterogeneous wired/wireless networks: resource management in DiffServ using the NSIS protocol suite

Reservation-based quality of service (QoS) in a mixed wireless and wireline environment requires an end-to-end signaling protocol that is capable of adapting to the idiosyncrasies of the different networks. The QoS NSIS signaling protocol (QoS-NSLP) has been created by the Next Steps In Signaling working group at the IETF to fulfill this need for an adaptive reservation protocol. It allows reservation requests to be interpreted by equipment implementing different QoS models along the path between a data sender and a data receiver. This paper describes the QoS-NSLP, and an example of a particular QoS model that is based on resource management in DiffServ (RMD). RMD provides a scalable dynamic resource management method for DiffServ networks. RMD has two basic functions to control the traffic load in a DiffServ domain: it provides admission control for flows entering the network and it has an algorithm that terminates the required amount of flows in case of congestion caused by failures (e.g. link or router) within a DiffServ domain. The admission control within the domain can be either measurement - or reservation-based. The basic signaling mechanism is described for different signaling scenarios and the expected performance of the protocol is discussed

Performance Evaluation of Reactive and Proactive Handover Schemes for IP Micromobility Networks

Micromobility protocols aim to improve localized mobility by reducing the handover overhead. The Mobility Plane Architecture (MPA) was designed to support micromobility in standard IP or MPLS/GMPLS networks in a network-centric way, that is, the burden demanded by micromobility is placed on the network, not on the mobile nodes. The aim of this paper is to present the reactive and proactive handover procedures supported by MPA, its modeling and performance evaluation. Results show that the proactive handover loses much less packets than reactive handover, being more suited for multimedia traffic.

Performance Analysis of a New Architecture for Mobility Support in IP Networks

In this paper, we describe a queueing network model representing the mobility plane architecture, which allows mobile users to register in the system and move around while stay connected. This paper presents a system overview, including node attachment, node updating and handover procedures. Two queueing network models and their evaluation on a simulation tool are presented, resulting in some important conclusions for our architecture and other micro-mobility proposals. Results show the importance of considering L2 and L3 association times because they can affect all procedures involving new registration and handover.

Design and Implementation of a Network-Centric Micro-Mobility Architecture

This paper presents the design and implementation of the Mobility Plane Architecture (MPA). MPA is a network architecture that provides micro-mobility in a network-centric way, that is, the burden of supporting micro-mobility is placed on the network and not on the mobile nodes. The implementation employs RSVP-TE to establish IP/IP and MPLS point-to-multipoint tunnels in order to direct traffic to the mobile nodes. DHCP is used for tracking the mobile node locations and RSVP-TE opaque data carries the location information to install routes to them. Results obtained in a lab-sized network and some quantitative comparisons between MPA and other related work are presented as well.