This book constitutes the thoroughly refereed post-proceedings of the International Conference on Information Networking, ICOIN 2006 held in Sendai, Japan in January 2006. The 98 revised full papers presented were carefully selected and improved during two rounds of reviewing and revision from a total of 468 submissions.

Together with its companion volume LNCS 2344, this book constitutes the refereed post-proceedings of the International Conference on Information Networking, ICOIN 2002, held in Cheju Island, Korea in January/February 2002.The 140 revised full papers presented were carefully selected and revised during two rounds of reviewing and improvement. The papers are organized in topical sections on new networking applications, switching and routing, optical networks, network performance, quality of service, home networking and local access protocols, network management, wireless and mobile Internet, 4 G mobile systems, satellite communication systems, network security, multimedia applications, and distributed systems.

Together with its companion volume LNCS 2343, this book constitutes the refereed post-proceedings of the International Conference on Information Networking, ICOIN 2002, held in Cheju Island, Korea in January/Febuary 2002.The 140 revised full papers presented were carefully selected and revised during two rounds of reviewing and improvement. The papers are organized in topical sections on new networking applications, switching and routing, optical networks, network performance, quality of service, home networking and local access protocols, network management, wireless and mobile Internet, 4 G mobile systems, satellite communication systems, network security, multimedia applications, and distributed systems.

This volume contains the set of revised selected papers presented at the 21st International Conference on Information Networking (ICOIN 2007), which was held in Estoril, Portugal, January 23-25, 2007. The conference series started under the name of Joint Workshop on Computer Communications, in 1986. At that time, it constituted a technical meeting for researchersand engineers on - ternet technologies in East Asian countries, where several technical networking issues were discussed. In 1993, the meeting was reorganized as an international conference known as ICOIN. Recent conferences were held in Sendai, Japan (2006), Jeju, Korea(2005), Pusan, Korea(2004), Jeju, Korea(2003), Jeju, Korea (2002), Beppu City, Japan (2001), Hsin-chu, Taiwan (2000), and Tokyo, Japan (1999). In 2007, for the ?rst time since its creation, ICOIN took place outside Asia, and we were very pleased to host it in Portugal. ICOIN 2007 was or- nized by INESC-ID and IST/Technical University of Lisbon (Portugal) with the technical co-sponsorship of IEEE Communications Society and IEEE Portugal Section-Computer Society Chapter, in cooperation with the Order of Engineers CollegeofInformaticsEngineering(Portugal), IPSJ(InformationProcessing- ciety of Japan), KISS (Korea Information Science Society), and Lecture Notes in Computer Science (LNCS), Springer, Germany. The papers presented in this volume were selected in two stages: 1) revi- ing and selection for the ICOIN program and 2) on-site presentation review by session chairs or by program committe