OBS网络中一种基于突发包优先级分割的可控重传方案

在光突发交换(OBS)网络中,突发包会由于竞争OBS核心节点输出端口的有限波长资源而发生冲突。突发包重传能够在一定程度上减少由于突发包在核心节点冲突而导致的数据损失,但重传次数的增加可能会加重网络负荷,反而增加数据丢失率。并且,在多业务存在的OBS网络中,重传方案需要能够实现区分服务以保证网络的服务质量(QoS)。据此,本文提出一种基于突发包优先级分割的可控重传方案,在实施优先级分割的同时,根据网络负荷赋予每次重传不同的概率,并对重传次数加以控制。最后,仿真分析了路径阻塞率和不同优先级业务的字节丢失率(ByLP,byte loss probability)性能。

A controllable retransmission scheme based on prioritized burst segmentation in OBS networks

In optical burst switching (OBS) networks,contentions may occur at th e output port of an OBS core node when the incoming bursts contend the limited wavelength resources.Bur st retransmission can reduce data loss due to the burst contention in OBS core nodes.But un controlled retransmission may increase network load and data loss probability significantl .In addition,in a priority traffic existing OBS network,retransmission mechanisms should realize different services to support the quality-of-service (QoS) of the network.According to this,in this paper,we develop a controllable retransmission scheme based on prioritized burst segmentation.Different from previous works in the literature, we apply the prioritized burst segmentation and set a different value to retrans mission probability at each contention and control the total transmission times referred to the network load condition.In addition,we apply the proposed retransmission scheme to the prioritized burst segmentation f or QoS support.We take the load at each link due to both the fresh and the retransmit ted traffic into account.At last,we calculate the path blocking probability and the byte loss probability (ByLP) for different priority bursts to evaluate the network performance.The results have some theoretical significance for the designing of an OBS network.