12th gi itg conference on measuring modelling and evaluation of computer communication systems 3rd polish german teletraffic symposium trends developments in ict industry new challenges for performance analysts rd van der mei a b bmm gijsen c cwi advanced networks amsterdam netherlands vrije universiteit faculty sciences tno telecom quality service delft e mail nl abstract the next few years landscape information communications technology will be subject to many changes services brought market offered over large highly distributed infrastructures consisting heterogeneity each owned by different parties business companies increasin gly depend their t he unbundling telecommunications world become reality classical role models value chains change third party providers enter network need negotiate level agreements sla s order offer high predictable levels customers
