In this paper, we study the dynamic performance of self-similar traffic under different integrated routing algorithms in IP/WDM networks for the first time. The self-similar traffic is generated by FFT-FGN method characterized by three parameters (<i>H, M, V</i>) namely Hurst parameter, Mean Value and variance Value. Through extensive simulation in three respective network topologies, the effects on the dynamic performance by the parameters of self-similar traffic (Hurst, Mean, Variance) and the parameter of network (connectivety of the topologies) are analyzed. we know that the network blocking probability increases with the rise of <i>H</i> and <i>V</i> due to the bursty of traffic becomes more obvious. And the increasing of <i>M</i> makes the network blocking probability higher because of increasing of traffic volume. Moreover different IR algorithms have different performance using self-similar model, and integrated min-hop routing (IMH) algorithm outperforms the others. All these trends are not changed with the connectivity of the network topologies. In addition, in order to know the difference of dynamic performance between the Poisson and self-similar model, we compare the performance of the two modes under the same condition. Simulation results show that network blocking probability of self-similar traffic is lager than that of Poisson due to the property of long-rage dependence of self-similar traffic.
Due to easy realization and high bandwidth utilization, SDH/WDM technology becomes the important way to carry IP traffic over the backbone network. On the other hand, the feature of the data traffic which is much different from the voice traffic is dynamic, burst and self-similar, and many proofs show that the self-similar traffic can lead to some adverse effects on the network performance due to the property of long-range dependence (LRD). For this reason it is widely recognized that self-similarity of the traffic is a significant problem as far as network engineering is concerned. So any reduction in the degree of self-similarity will be greatly beneficial. One possible strategy for mitigating the deleterious effects of the self-similarity is to reduce the burstiness of the input traffic through traffic shaping function at the edge nodes. According to this scheme, in this paper, we present a new self-similar traffic shaping mechanism with QoS in transport networks, called double threshold algorithm (DTA). Simulation results show that the proposed mechanism can effectively reduce the degree of input self-similar traffic, and performs better in the terms of network packet-loss rate and blocking probability than the non-traffic shaping schemes. At the same time it guarantees good quality of service.
Recently, several existing and proposed network architectures of IP over WDM are discussed. The twolayer model, which aims at a tighter integration between IP and WDM layers, offers a series of important advantages over the multi-layer architecture. Multiprotocol Label Switching (MPLS) and its extension, Generalized Multiprotocol Label Switching (GMPLS), have been proposed as the integrating structure between IP and WDM layers. Several integrated routing algorithms (IR) have been proposed to solve the routing problem in IP/WDM networks. But few of these algorithms consider the physical hop and the bandwidth fragments, which will results in some drawbacks. This paper develops a new integrated on-line routing algorithm, called hop-based bandwidth defragment algorithm (HBD). It makes uses of the statistic information of link-state and resource availability to determine whether it is better to route an arriving request over the existing topology or to open new wavelength paths. The HBD algorithm is not only to minimize the total number of physical hops used by the existing lightpaths and new lightpaths created for routing LSPs, but also to minimize the number of bandwidth fragments, which will possibly lead to increased acceptance of requests that arrive later. Simulation results show that HBD performs better in terms of blocking probability and bandwidth blocking ratio than other existing approaches.
In this paper, we propose two novel dynamic adaptive routing grooming algorithms for optical WDM mesh networks using the fixed alternate routing (FAR) approach. The algorithms consider both load balance and resources utilization in the network and use FAR mechanism to reduce computation complexity and transmission delay. The simulation results show that the network performance can be improved significantly by these algorithms.