Quality of Service in OBS Networks: Issues, Challenges and Solutions

In OBS networks, contention caused by multiple bursts competing simultaneously for a given wavelength on a fiber link, significantly increases the burst dropping probability and hence deteriorates the overall network performance. Several studies tackled the contention resolution in OBS networks; however several issues still need to be addressed such as quality of service (QoS) guarantee, protection and restoration. The separation between the control plane and data plane in OBS networks provides the flexibility needed by next generation networks. However, it raises the complicated calculation problem of the appropriate offset time for each burst to reach its destination without dropping. In this paper, we stress out the QoS guarantee, protection and restoration challenges in OBS networks. We focus on the importance of the choice of the offset time and its criticality in influencing: (i) the burst loss phenomenon in OBS networks, and (ii) the protection/restoration strategies