Quality of Service in IP Networks IP networks were designed some 25 years ago. Networks based on TCP/IP are widely deployed, as organization-local Intranets as well as in the Internet itself. The usage patterns of those networks change. Especially new technologies like voice-over-IP as well as streaming multimedia applications have different requirements on the underlying network infrastructure than bulk data transfers like ftp/www or interactive traffic like telnet/ssh. Organizations usually run a mixture of different services on their Internet uplinks or on their organization-internal wide area networks. Bandwidth is usually a limited ressource, so everybody wants to divide bandwidth between different services according to his specific needs. Linux always had a very strong focus on network functionality and has sophisticated means for bandwidth control / QoS since Kernel 2.2. The presentation is organized in the following parts: Basics of QoS in IP networks How can Linux help with QoS Sample scenarios of Linux-based QoS solutions Overview about advanced conecpts (DiffServ, IntServ, RSVP, ...)