光突发交换网络的数据突发延滞调度策略分析

Analysis of data burst delay scheduling policy in OBS networks

目的改善光突发交换(OBS)网络的QoS性能。方法提出了一种新的光迟延线(FDL)缓冲调度方法,即突发延滞调度策略。结果利用FDL将竞争中的低优先级DB做适当延时,通过BCP的二次信令调整OBS网络中该数据突发(DB)的波长信道预约,以解决突发的竞争问题;通过理论分析和系统仿真方法研究了OBS网络业务流量对DB丢失率和端到端时延的影响。结论该策略能有效地解决OBS网络中DB的竞争现象,为高优先级DB提供了端到端的QoS保证。

Aim To improve the QoS performance of OBS networks. Methods Propose a novel buttering and scheduling scheme with FDL, namely data bursts delay scheduling policy. Results The low-priority class data burst （DB） is buffered with FDL in order to forward the high-priority DB as early as possible when contending at a core node, and the reserved wavelength channel for the low-priority DB will be re-assigned to the contending highpriority DB by sending a new burst control packet （BCP） , which is called the second BCP signaling, from the node to the downstream nodes. The effects of network traffic loads and the size of FDL buffer on DB＇s loss probability and end-to-end delay are studied by an OBS network system simulation and theoretical analyzing. Conclusion The proposed scheduling policy can reduce obviously DB loss probability and end-to-end delay for high-priority DB. So it can provide better end-to-end QoS for high-priority DBs.