The 2008 edition of the Passive and Active Measurement Conference was the ninth of a series of successful events. Since 2000, the Passive and Active M- surement (PAM) conference has provided a forum for presenting and discussing innovative and early work in the area of Internet measurement.

Addressing and Topology.- The Flattening Internet Topology: Natural Evolution, Unsightly Barnacles or Contrived Collapse?.- Assessing the Geographic Resolution of Exhaustive Tabulation for Geolocating Internet Hosts.- Observations of IPv6 Addresses.- Applications.- The New Web: Characterizing AJAX Traffic.- Measurement and Estimation of Network QoS Among Peer Xbox 360 Game Players.- Evaluation of VoIP Quality over WiBro.- Classification and Sampling.- Packet Sampling for Flow Accounting: Challenges and Limitations.- On the Validation of Traffic Classification Algorithms.- Evaluation of Header Field Entropy for Hash-Based Packet Selection.- Measurement Systems and Frameworks.- A Reactive Measurement Framework.- Towards a High Quality Path-Oriented Network Measurement and Storage System.- On Community-Oriented Internet Measurement.- Wireless 802.11.- On the Effectiveness of Switched Beam Antennas in Indoor Environments.- On the Fidelity of 802.11 Packet Traces.- Refocusing in 802.11 Wireless Measurement.- Tools.- Pathdiag: Automated TCP Diagnosis.- SCUBA: Focus and Context for Real-Time Mesh Network Health Diagnosis.- IMR-Pathload: Robust Available Bandwidth Estimation Under End-Host Interrupt Delay.- Characterization and Trends.- A Measurement Study of Internet Delay Asymmetry.- Trends and Differences in Connection-Behavior within Classes of Internet Backbone Traffic.- The Cubicle vs. The Coffee Shop: Behavioral Modes in Enterprise End-Users.- Malware and Anomalies.- A Two-Layered Anomaly Detection Technique Based on Multi-modal Flow Behavior Models.- Malware in IEEE 802.11 Wireless Networks.

This book constitutes the refereed proceedings of the 9th International Conference on Passive and Active Measurement, PAM 2008, held in Cleveland, OH, USA, in April 2008. The 23 revised full papers presented were carefully reviewed and selected from 71 submissions. The papers focus on research and practical applications of network measurement and analysis techniques and are organized in topical sections on addressing and topology, applications, classification and sampling, measurement systems and frameworks, wireless 802.11, tools, characterization and trends, and malware and anomalies.