Abstract— In this paper, a framework for operation and maintenance (OAM) procedures in an optical burst switched (OBS) network is proposed and investigated. They are considered in three different axes. The first axis considers OAM operations from a mechanism’s point of view that would help in designing an OAM engine and in deriving relevant OAM procedures. The serving functions of OAM operations are distinguished along the second axis. Finally, the third axis addresses an information model and communication channel aspect. Index Terms—Optical burst switching (OBS); operation and maintenance (OAM); operation, administration, and maintenance (OAM); optical networks; network management I. INTRODUCTION Optical Burst Switching (OBS) has received considerable attention recently as a future possibility for optical switching in multi-wavelength optical networks. It proposes a new switching granularity (in between the granularity of a wavelength circuit and that of a traditional data packet) for high-speed forwarding of data and for achieving a statistical multiplexing gain [1]. At the ingress edge of the OBS network, several data packets with the same egress address and with common attributes (e.g., common QoS parameters) are assembled into a jumbo packet, called Data Burst (DB). For every DB, a “Burst Header Packet” (BHP) is created to host the control information for forwarding and switching the DB. A DB and its corresponding BHP are de-coupled spectrally (spatially, if DB and BHP are carried over different fibers) and temporally. The DB is transmitted over a dedicated data channel (wavelength) while its BHP is transmitted over a dedicated control channel (wavelength). For every group of data channels a control channel, or more, may be assigned. On the temporal side, time must be allowed for BHPs processing delays. A common approach to do this is by introducing an offset time between transmission of BHPs and their DBs. In this case, a BHP arrives at an intermediate core node before its DB, goes through optical-to-electrical (O/E) conversion, and gets processed electronically in order to configure the optical switch fabric for the DB. The latter flies through in the optical domain. At the egress OBS edge node, the DB is disassembled back into its original data packets, which are forwarded to their destination(s) outside the OBS network. Although OBS has been investigated from the perspective of some control and Quality-of-Service (QoS) considerations [2, 3], operation and maintenance (OAM) issues of OBS have not received much attention. OAM is an essential aspect to ensure proper, and reliable, network operation. It provides tools for both preventing and responding to failures or defects that may occur during network operation. An OAM study for OBS can benefit from previous OAM work in other areas, such as Asynchronous Transfer Mode (ATM) networks [4], Synchronous Optical Network/ Synchronous Digital Hierarchy (SONET/SDH) systems [5], WDM-based optical networks [6] and Multi-protocol Label Switching (MPLS) networks [7]. However, OBS has unique characteristics to consider in a specialized OAM framework. These characteristics include spectral (possibly spatial) and temporal de-coupling of DBs and BHPs. A mechanism to monitor and synchronize these entities is essential, along with other OBS related operations. The rest of this paper is organized as follows. In Section II, we explore OBS-specific OAM considerations and propose an OBS node architecture that enables OAM functionalities. In Section III, we discuss two fundamental procedures for OAM mechanisms. Two functions which OAM activities should satisfy are presented in Section IV. OAM information models are then proposed in Section V followed by a brief consideration on OAM operational protocol in Section VI. Finally, Section VII concludes the paper. II. OAM IN OBS NETWORKS A. OAM Considerations in OBS Two distinct features differentiate OBS from other networks and need to be brought to attention from an OAM perspective: • Spectral (spatial) de-coupling, with possible wavelength conversion for contention resolution at intermediate optical core nodes. This requires a mechanism to relate DBs to their associated BHPs and a network-wide wavelength reference/standard. • Temporal de-coupling between every DB and its BHP, with possible re-timing at intermediate node(s). This requires the network to keep track of timing information of each DB/BHP pair along their journey up to destination edge node. These two distinct characteristics generate special OAM requirements and warrant a fresh look into OAM undertaking in OBS networks. Probable problems due to these features include out-of-order reception of BHP and DB, “direction- less” DBs (lost their BHPs), “orphan” BHPs (lost their DBs), optical switch fabric mis-configuration, burst mis-routing, burst aggregation/assembly process malfunction, out-of- sequence arrival of bursts at destination edge node(s), etc. Framework for Operation and Maintenance Procedures in Optical Burst Switched Networks Jong-Dug Shin, Saravut Charcranoon, Hakki C. Cankaya, and Tarek S. El-Bawab Network Strategy Group, Alcatel USA