M. Ricardo - Academia.edu (original) (raw)

Papers by M. Ricardo

Simulation Modelling Practice and Theory, 2011

In the networking research and development field, one recurring problem faced is the duplication ... more In the networking research and development field, one recurring problem faced is the duplication of effort to write first simulation and then implementation code. We posit an alternative development process that takes advantage of the built in network emulation ...

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... Graduation project DEEC IP over WDM Designing an Optical IP Router Supervisors StudentsHenr... more ... Graduation project DEEC IP over WDM Designing an Optical IP Router Supervisors StudentsHenrique Salgado, PhD Manuel Ricardo, PhD Bruno Leite Fernando Pinto Igor Terroso Joel Carvalho Page 2. Page 3. Acknowledgements Page 4. Page 5. ...

P2P Video Streaming has become a reliable and efficient solution for distributing video on the In... more P2P Video Streaming has become a reliable and efficient solution for distributing video on the Internet. Similarly to regular P2P file-sharing, all the participating nodes exchange information. Wireless Mesh Networks, in turn, can be seen as a cost-effective solution to extend Internet access networks. In this paper we propose improvements to P2P Video Streaming. These improvements can provide gains in

Abstract: This document describes the QoS framework developed under the ARROWS project. This QoS ... more Abstract: This document describes the QoS framework developed under the ARROWS project. This QoS framework provides a solution for deploying IP based multimedia applications over UMTS access networks and provides these applications with the Quality ...

XCP-b proposes a modification to the XCP router algorithm that computes the spare bandwidth. The ... more XCP-b proposes a modification to the XCP router algorithm that computes the spare bandwidth. The modification removes the need for an XCP router to know the exact capacity of the channel, making it possible to use the XCP-b variant in transmission media where the capacity is hard to measure. An example of this kind of medium is the IEEE 802.11. Previous work shows that XCP-b behaves well in single-hop wireless networks and that it outperforms TCP in terms of fairness, queuing delay, stability and efficiency when the bandwidth delay product of the network grows. In this paper we extend the validation and evaluation of XCP-b to the case of multi-hop wireless networks, both stand-alone and as access networks to other wired networks.

Factors such as the growing number of multimedia terminals, the constant increase of bandwidth av... more Factors such as the growing number of multimedia terminals, the constant increase of bandwidth available per user, and the large number of existing data sharing applications, are compelling users to generate and distribute their own content to restricted groups of other users. Inorder to support such scenario, we present an IMS-based solution that enables content distribution, in multicast, to groups of users, where the source of the content is also an end-user. The proposed solution allows the source of content to configure the service, indicating a list of authorized receivers and both the transmission date and duration. Moreover, the proposed solution also allows the operator to manage the registered user profiles, to impose access control and to validate the configurations submitted by the users.

Ubiquitous Internet access is becoming crucial for end-users due to the increasing number of serv... more Ubiquitous Internet access is becoming crucial for end-users due to the increasing number of services and applications supported over the Internet. Extending the coverage of current Wi-Fi infrastructures installed in companies, universities, and cities, has been considered a solution to help in fulfilling this requirement, namely when it comes to wireless and nomadic Internet access.

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The development of communications systems demands testing. This paper presents a framework for te... more The development of communications systems demands testing. This paper presents a framework for testing onthe-fly, which relies on the identification of 3 types of tests and on their sequential execution. The ioco conformance relation was adopted in order to assign verdicts.

Computer Networks, 2000

Future public transportation systems will provide broadband access to passengers, carrying legacy... more Future public transportation systems will provide broadband access to passengers, carrying legacy terminals with 802.11 connectivity. Passengers will be able to communicate with the Internet and with each other, while connected to 802.11 Access Points deployed in vehicles and bus stops/metro stations, and without requiring special mobility or routing protocols to run in their terminals. Existing solutions, such as 802.11s and OLSR, are not efficient and do not scale to large networks, thereby requiring the network to be segmented in many small areas, causing the terminals to change IP address when moving between areas.This paper presents WiMetroNet, a large mesh network of mobile routers (Rbridges) operating at layer 2.5 over heterogeneous wireless technologies. This architecture contains an efficient user plane that optimizes the transport of DHCP and ARP traffic, and provides a transparent terminal mobility solution using techniques that minimize the routing overhead for large networks. We offer two techniques to reduce routing overhead associated with terminal mobility. One approach is based on TTL-limited flooding of a routing message and on the concept of forwarding packets only to the vicinity of the last known location of the terminal, and then forward the packets to a new location of the terminal. The other technique lets the network remain unaware for a very long time that the terminal has moved; only when packets arrive at the old PoA does the PoA send back a “binding update” message to the correspondent node, to correct the route for future packets for the same terminal.Simulation and analytical results are presented, and the routing protocol is shown to scale to large networks with good user plane results, namely packet delivery rate, delay, and handover interruption time.

When networking researchers meet the task of doing simulations, there is always a need to evaluat... more When networking researchers meet the task of doing simulations, there is always a need to evaluate the value of such models by measuring a set of well known network performance metrics. However, simulators in general and NS-3 in particular, require significant programming effort from the researcher in order to collect those metrics. This paper reports a contribution for NS-3 consisting of a new flow monitoring module that makes it easier to collect and save to persistent storage a common set of network performance metrics. The module automatically detects all flows passing through the network and stores in a file most of the metrics that a researcher might need to analyze about the flow, such as bitrates, duration, delays, packet sizes, and packet loss ratio.

This paper addresses Wireless Networks for Metropolitan Transports (WNMT), a class of moving or v... more This paper addresses Wireless Networks for Metropolitan Transports (WNMT), a class of moving or vehicleto-infrastructure networks that may be used by public transportation systems to provide broadband access to their vehicles, stops, and passengers. We propose the WiMetroNet, a WNMT that is auto-configurable and scalable. It is based on a new Ad hoc routing protocol, the Wireless Metropolitan Routing Protocol (WMRP), which, coupled with data plane optimizations, was designed to be scalable to thousands of nodes.

Simulation Modelling Practice and Theory, 2011

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Computer Networks, 2000