Research networks, apart from pure IP packet-switched services, progressively introduce hybrid services, which combine packet switching and circuit switching technologies. Optical wavelengths (lambdas), SONET/SDH, 1/10 Gigabit Ethernet are examples of technologies stitched together in order to realize point-to-point (p2p) services that cross multiple domains. Network monitoring aims to detect anomalies, assess performance degradations and localize faults in a network. In this paper, we discuss the challenges of monitoring p2p hybrid services deployed in a multi-domain environment. We briefly discuss diverse methods of transporting Ethernet traffic over hybrid networks and present performance metrics related to various layer 1/2 technologies. We give an example of a hybrid service and discuss why it is challenging to identify service degradation problems in a multi-domain environment.