1 The Network of Excellence on Next-Generation Internet (EuroNGI), and its extension, Future-Generation Internet (EuroFGI), is a European project funded bythe EuropeanUnionwithin the ISTSixth FrameworkProgram.Thetargetof the EuroNGI/FGI network is to put together European research centers in the ?eld of networking,focusing on next-generationInternet designand engineering. In all, 60 partners from technical universities and research centers in Europe participate in EuroNGI/FGI. Oneofthe"IntegrationActivities"withinEuroNGI/FGIconsistsoftheor- nizationofanannualWorkshoponWirelessandMobility.Theworkshopintends to bring together leading researchersfrom the Networkof Excellencein this ?eld of research in order to identify the fundamental challenges and future persp- tivesofthisimportantarea. This post-proceedings volume contains a selection of the research cont- butions presented at the fourth edition of the workshop. The workshop was held January 16-18, 2008 in Barcelona, Spain, organized by CompNet Research 2 Group from the Universitat Polit' ecnica de Catalunya (UPC).The previous editions of the workshop were also organized by UPC in Sitges, Spain, in 2006; by Politecnico di Milano in Lago di Como, Italy, in 2005; and by Rheinisch- Westf. alischen Technischen Hochschule Aachen in Dagstuhl, Germany, in 2004. To participate in the workshop, the authors submitted an extended abstract of their ongoing work in the ?eld of wireless and mobility. From a total of 39 submissions, 28 were accepted for presentation. Following the discussions and suggestions made in the workshop, the authors submitted 26 full papers that were carefully reviewed by experts on the ?eld. Finally, 16 papers incorporating the numerous referee comments were accepted for publication in this book.

1 The Network of Excellence on Next-Generation Internet (EuroNGI), and its extension, Future-Generation Internet (EuroFGI), is a European project funded bythe EuropeanUnionwithin the ISTSixth FrameworkProgram.Thetargetof the EuroNGI/FGI network is to put together European research centers in the ?eld of networking,focusing on next-generationInternet designand engineering. In all, 60 partners from technical universities and research centers in Europe participate in EuroNGI/FGI. Oneofthe"IntegrationActivities"withinEuroNGI/FGIconsistsoftheor- nizationofanannualWorkshoponWirelessandMobility.Theworkshopintends to bring together leading researchersfrom the Networkof Excellencein this ?eld of research in order to identify the fundamental challenges and future persp- tivesofthisimportantarea. This post-proceedings volume contains a selection of the research cont- butions presented at the fourth edition of the workshop. The workshop was held January 16-18, 2008 in Barcelona, Spain, organized by CompNet Research 2 Group from the Universitat Polit' ecnica de Catalunya (UPC).The previous editions of the workshop were also organized by UPC in Sitges, Spain, in 2006; by Politecnico di Milano in Lago di Como, Italy, in 2005; and by Rheinisch- Westf. alischen Technischen Hochschule Aachen in Dagstuhl, Germany, in 2004. To participate in the workshop, the authors submitted an extended abstract of their ongoing work in the ?eld of wireless and mobility. From a total of 39 submissions, 28 were accepted for presentation. Following the discussions and suggestions made in the workshop, the authors submitted 26 full papers that were carefully reviewed by experts on the ?eld. Finally, 16 papers incorporating the numerous referee comments were accepted for publication in this book.

1 The Network of Excellence on Next-Generation Internet (EuroNGI), and its extension, Future-Generation Internet (EuroFGI), is a European project funded bythe EuropeanUnionwithin the ISTSixth FrameworkProgram.Thetargetof the EuroNGI/FGI network is to put together European research centers in the ?eld of networking,focusing on next-generationInternet designand engineering. In all, 60 partners from technical universities and research centers in Europe participate in EuroNGI/FGI. Oneofthe"IntegrationActivities"withinEuroNGI/FGIconsistsoftheor- nizationofanannualWorkshoponWirelessandMobility.Theworkshopintends to bring together leading researchersfrom the Networkof Excellencein this ?eld of research in order to identify the fundamental challenges and future persp- tivesofthisimportantarea. This post-proceedings volume contains a selection of the research cont- butions presented at the fourth edition of the workshop. The workshop was held January 16-18, 2008 in Barcelona, Spain, organized by CompNet Research 2 Group from the Universitat Polit' ecnica de Catalunya (UPC).The previous editions of the workshop were also organized by UPC in Sitges, Spain, in 2006; by Politecnico di Milano in Lago di Como, Italy, in 2005; and by Rheinisch- Westf. alischen Technischen Hochschule Aachen in Dagstuhl, Germany, in 2004. To participate in the workshop, the authors submitted an extended abstract of their ongoing work in the ?eld of wireless and mobility. From a total of 39 submissions, 28 were accepted for presentation. Following the discussions and suggestions made in the workshop, the authors submitted 26 full papers that were carefully reviewed by experts on the ?eld. Finally, 16 papers incorporating the numerous referee comments were accepted for publication in this book.