Research On The Usage And Allocation Of Grooming Ports In WDM Networks

With the rapid development of Internet technology,network technology has already extended to all areas and communication traffic is in explosive growth.However,to meet people's increasing demand,the network bandwidth and communication devices increase continually,but the problem of energy consumption has cropped up.The greenhouse effect is worsening and global energy crisis appears.Thus it's urgent to reduce energy consumption of communications equipment.The study on energy-saving technology of optical network has become one of the current research focuses.The number of electrical switching units is much smaller than that of optical switching units in the optical/electrical hybrid switching devices.It can be explained by two reasons: one is high power consumption of electrical switching units;another one is that the complexity and the cost of large-scale multi-stage switching network composed of electrical switching units is large.However,due to the need of traffic grooming techniques for large capacity of traffic transmission,it has to use electric switch ports.The main work of this thesis is to minimize the use of the ports with a reasonable use of the ports and wavelengths,and to reduce power consumption in the network under the premise of ensuring network lower blocking ratio.The main work of this thesis is as follows:(1)The primary nodes algorithm is proposed.According to the importance of the nodes,all the nodes are classified into primary nodes and secondary nodes,which the primary nodes have traffic grooming capability with a llocating electric switch ports,and the secondary nodes have not.This can reduce the grooming ports and power consumption in the network greatly.It includes static and dynamic primary nodes algorithms.Static primary nodes algorithm classifies primary and secondary nodes and allocates grooming ports under the network load known before the network running.By simulation analysis,it finds that the energy-saving effect of static primary nodes algorithm is particularly obvious at lower load,but having no effect after 90 Erlang.It is only applicable for the network which load is known a nd lower.In order to overcome the disadvantage of static primary node algorithm,dynamic primary nodes algorithm is proposed.It can sense the changes of network load and switch electric ports dynamically depending on network load.When the network load is larger,electric ports are turned on in a timely manner in order to ensure network traffic transports normally.When the network load is lower,some extra ports are turned off to reduce power.The simulation results show that dynamic primary node algorithm is not only reducing power consumption at low loads,but also can do it at high loads,even reducing blocking rate within a certain range.(2)Ports allocation strategy is proposed.Because each node has different grooming capability in the network,the grooming ports they use are also different at the same load.The traditional method allocates ports uniformly,which can cause that some nodes are not enough for ports but other nodes have some remaining free ports.So the ports cannot be taken advantage of.The ports allocation strategy classifies nodes in the network into three categories,big,small and intermediate nodes based on the importance of them.Allocate more ports for big nodes and fewer ports for small nodes.For the intermediate nodes the appropriate amount of ports are allocated.In this thesis port allocation strategy is implemented respectively in the general environment and the dynamic primary nodes algorithm.The simulation results show that the port allocation strategy can save energy efficiently,but also can lower blocking rate,especially based on the dynamic primary node algorithm.