Performance analysis of asynchronous best-effort traffic coexisting with TDM reservations in polymorphous OBS networks (original) (raw)

The in-advance reservation of bandwidth capacity philosophy of Optical Burst Switching architectures via Burst-Control Packets brings high flexibility in the separation of network resources for services with different qualityof-service requirements. In this light, real-time applications can periodically be guaranteed a certain amount of bandwidth reservation for the transmission of traffic with Constant Bit Rate requirements (for instance IP television, VoIP, etc), whilst the remaining capacity may be used for transmission of best-effort traffic of the so-called elastic applications (e-mailing, web browsing, etc). The Polymorphous, Agile and Transparent Optical Networks (PATON) architecture (Qiao et al. IEEE Commu Mag 44(12):104-114 2006) proposes periodic reservation of time-slots over one or several wavelengths of an optical fibre, yet remaining gaps in between them for transmission of best-effort traffic. This work presents a novel analysis of the performance perceived by best-effort traffic which are given full access to optical switching only during a portion of the total time. The following analyses the nonblocking probability among best-effort data bursts that share such available gaps in between the periods of CBR traffic. An exact expression of the non-blocking probability is derived when a single wavelength is used for CBR traffic, along with a lower bound for the case when CBR traffic is transmitted using multiple wavelengths. These results can be of further interest in the optimal design of OBS architectures where the transmission of high-priority real-time traffic and best-effort data coexist over the same wavelength.