Thebeginningofthe21stcenturyiswitnessingadrivetotheconvergenceof?xed and mobile telecommunication networks and the increasing adoption of IP te- nologies for implementing seamless multimedia applications in next-generation networks. The IEEE International Workshop Series on IP Operations & M- agement (IPOM) is documenting this evolution by providing snapshots of the state of the art in the ?eld of operations and management in IP-based networks. The 5th IEEE International Workshop on IP Operations & Management (IPOM2005),devotedtothe O&MChallengesinNextGenerationServicesand Networks , was held in Barcelona, Spain, October 26 28, 2005. Here IPOM was one of the ?ve collocated events under the banner First International Week on ManagementonNetworksandServices(www.manweek2005.org) ,togetherwith the 16th IFIP/IEEE International Workshop on Distributed Systems: Ope- tionsandManagement(DSOM2005),the8thInternationalConferenceonM- agement of Multimedia Networks and Services (MMNS 2005), the 2005 Sym- siumonSelf-stabilizingSystems(SSS2005)andthe1stIEEE/IFIPInternational Workshop on Autonomic Grid Networking and Management (AGNM 2005). Thisbookcontainstheo?cialproceedingsofIPOM2005.Itfeatures21hi- quality papers grouped into seven technical sessions looking at O&M for VoIP, IMS and managed IP services, management of open interfaces, QoS and pricing in NGNs, autonomic communications, policy-based management, routing and topologies, routing and tools, as well as experiences from testbeds and trials. Additional papers presented in two short sessions are published separately. Wewouldliketothanktheauthorsforalltheire?orts,aswellasthemembers of the Technical ProgramCommittee, and the reviewers. Without their support the high-quality program of this event would not have been possible. We are also indebted to many individuals and organizations that made the conference possible (IEEE, IARIA, Fraunhofer Institute FOKUS, JEMS s drivers, and the Universitat Polit` ecnica de Catalunya).