**1. Introduction**

The ever-growing demand of high-quality broadband connectivity in mobile scenarios, as well as the Digital Divide discrimination, are boosting the development of more and more efficient wireless technologies.

Despite their adaptability and relative small installation costs, wireless networks still lack a full bandwidth availability and are also subject to interference problems.

In context of a Metropolitan Area Network serving a large number of users, a bandwidth increase can turn out to be neither feasible nor justified. In consequence, and in order to meet the needs of multimedia applications, bandwidth optimization techniques were designed and developed, such as Traffic Shaping [1-3], Policy-Based Traffic Management [4- 8] and Quality of Service (QoS) [9-17].

In this paper, QoS protocols are adopted and, in particular, priority-based dynamic profiles in a QoS wireless multimedia network. This technique [18-20] allows to asssign different priorities to distinct applications, so as to rearrange service quality in a dynamic way [21,22] and guarantee the desired performance to a given data flow.

In particular, the platform can manage two levels of priority: among different users and within a single user's connection.

In the former kind of priority management, those users whose guaranteed bandwidth is higher, will be proportionally assigned a greater part of the shared bandwidth.

The latter case refers to each single user, whose distinct services are assigned distinct priorities. Each profile, in fact, allows the real time management of services, and the priority parameter is used to queue the desidered services properly.

A complete testbed involving 80 users approximately is here presented, where such technique is adapted to the specific requirements of the plant.

The network infrastructure installation is detailed, the whole QoS system developed is described and four measurement campaigns are reported.

A Testbed About Priority-Based Dynamic

management software.

Fig. 1. the QoS equipment.

serve 35 users approximately.

traffic surrounding the pitch.

means of an electronic filter.

**2.2 The QoS architecture adopted** 

ground prevented a direct connection from being created.

Connection Profiles in QoS Wireless Multimedia Networks 79

Such system runs on a Dual Xeon 2 GHz, 8Gb di Ram, 80Gb SAS Raid 5 server and comprehends a Radius authentication server, a PPPoE concentrator and the whole QoS

A HiperLAN link starts here and connects the management server to a waterworks area (C) 15 km away (Link 2). In such area, two sectoral distribution equipments were setup and

A further antenna allows to reach the last distribution area, situated near a football pitch (D) 10.5 km away (Link 3), and including three further sectoral distribution equipments for 45 users approximately. Such antenna had to be setup since some unfavourable features of the

The indirect link creates a bottleneck and forces the waterworks area to support some of the

A further penalty is that the same pylon which hosts the antenna in area (C) also carries some television and microwave aerials. In consequence, some devices not optimally shielded were

In addition, some further installation problems were caused by the daily activation of the waterworks pump, which produced strong perturbations to the electric network, consequent blocks of many devices and even breakdowns. This problem was solved by

All the above problems would have obviously prevented 80 users from being propely served, unless a bandwidth optimization method and traffic management were adopted.

The QoS scheme is based on the dynamic assignment and redistribution of bandwidth on the basis of priority and users' profiles. The main parameters of each kind of profile are

initially blocked and even damaged and the available bit-rate is still being diminished.

The whole testing was directed by WiLab (www.wilab.org), which includes the IEIIT-CNR (National Research Council of Italy, IEIIT Bologna unit) and a portion of the TLC scientific community at Bologna University (Italy). The design and technical aspects of the problem were and are still being carried out by such group.

The proposed platform aims at supporting a Wireless Internet Service Provider (WISP) in the management of its network infrastructure in a user-friendly and straightforward way. It can be accessed through the Internet and lets the network manager define different access profiles and supervise all the users' connections.

The QoS service, in particular, allows to set each user's minimum bit rate guaranteed and maximum supported, enable services such as VoIP, FTP, Mail and P2P and assign them specific priorities.

The network scenario installed and used for the testbed includes an Internet gateway, a server which hosts the whole infrastructure control system and five sectoral distribution devices.

The software platform allows to define some distinct kinds of priority-based connection profiles, each characterized by a set of different parameters and a diverse commercial value. Personal data can also be managed, each corresponding to the user's kind of connection profile subscribed.

Reports about connections and traffic statistics are also at disposal, also useful to law purposes. A continuous monitoring of the wireless network infrastucture is also possible.

All the above features can be easily managed through specific user-friendly portals.

This kind of services are fundamental in many application fields, ranging from Intelligent Transportation Systems (ITS) and Infomobility to "Smart Cities", where wireless applications guide the user in most of his activities.

The paper is organized as follows: Section 2 describes the testbed setup and the QoS software developed. Section 3 details the results of the four measurements campaigns.

These techniques, addressed to to real applications, are discussed in the following: the PEGASUS project about the support of real time in Infomobility is discussed in Section 4. The Smart Cities scenario is presented in Section 5. Conclusions and future tesbed extensions are discussed in Section 6.
