This paper proposes a new wavelength conversion algorithm in a DWDM network using online routing. The model for the algorithm has been theoretically developed and the corresponding call connection probability has been calculated. The limitation on the number of wavelength conversions has been addressed by fixing the maximum number of wavelength conversions allowed for the transmissions of a single packet over the network. The algorithm proposed is deterministic. It employs the concept of online routing to implement 'look ahead' characteristics and thus aims to design an intelligent WDM network. © 2003 Elsevier B.V. All rights reserved.