Seamless integration of heterogeneous constrained networks in the internet of things is still a challenging issue. However, with recent advances in smart objects networking, the IP architecture through 6LoWPAN is made possible and hence service oriented architecture is emerging as a promising solution. The key element to succeed any service oriented system is efficient service discovery. In this paper, we classify emerging 6LoWPANs' service discovery protocols, identify the gap in the 6LoWPAN service discovery literature and then briefly describe our solution aiming to fill this gap.