We present a practical solution for dynamic spectrum management(DSM) in digital subscriber line systems: the normalized-rateiterative algorithm (NRIA). Supported by a novel optimizationproblem formulation, the NRIA is the only DSM algorithm thatjointly addresses spectrum balancing for frequency divisionduplexing systems and power allocation for the users sharing acommon cable bundle. With a focus on being implementable ratherthan obtaining the highest possible theoretical performance, theNRIA is designed to efficiently solve the DSM optimization problemwith the operators' business models in mind. This is achieved withthe help of two types of parameters: the desired network asymmetryand the desired user priorities. The NRIA is a centralized DSMalgorithm based on the iterative water-filling algorithm (IWFA)for finding efficient power allocations, but extends the IWFA byfinding the achievable bitrates and by optimizing the bandplan.It is compared with three other DSM proposals: the IWFA, theoptimal spectrum balancing algorithm (OSBA), and the bidirectionalIWFA (bi-IWFA). We show that the NRIA achieves better bitrateperformance than the IWFA and the bi-IWFA. It can even achieveperformance almost as good as the OSBA, but with dramaticallylower requirements on complexity. Additionally, the NRIA canachieve bitrate combinations that cannot be supported by any otherDSM algorithm.