If time units are omitted, all specifications are assumed to be the same relative units. Entities (Elements): Arc: An Arc connects two Nodes in a QueueingNetworkModel. Traversal of an Arc represents completion of a service request at the FromNode and a new request for service at the ToNode. ClosedWorkload: A ClosedWorkload is a Workload with a fixed population that circulates among the Servers. DemandServiceRequest: A DemandServiceRequest specifies the average service demand (service time multiplied by number of visits) provided for each workload that visits the Server. Node: A Node represents an entity in the QueueingNetworkModel of the execution environment that either provides service or designates model topology. Non-ServerNode: A Non-ServerNode represents a Node of the execution environment that designates model topology but does not provide processing service. OpenWorkload: An OpenWorkload is a workload with a potentially infinite population where transactions or jobs arrive from the outside world, receive service, and exit. The population of the OpenWorkload at any one time is variable. ExternalNegativeArrival: A ExternalNegativeArrival is only used when G-Networks are considered. It represents that something that arrives from the outside word can kill a transaction or job that is already in the network. ????? InternalNegativeCustomer: An InternalNegativeCustomer is only used when G-Networks are considered. It represents that the service completion on one server causes the kiling of a transaction or job that is already in another server. ????? G-NetworkModel: A GNetworkModel represents a network of connected servers that provides processing service for Workloads, including negative customers. ?????? Server: A Server represents a Node of the execution environment that provides some processing service. ServiceRequest: A ServiceRequest specifies either the average TimeService or DemandService provided for each workload that visits the Server. SinkNode: A SinkNode represents a Node of the execution environment that designates where OpenWorkloads terminate. SourceNode: A SourceNode represents a Node of the execution environment that designates where OpenWorkloads originate. TimeServiceRequest: A TimeServiceRequest specifies the average service time and number of visits provided for each workload that visits the Server. Workload: A Workload represents a collection of transactions or jobs that make similar service requests from servers in the QueueingNetworkModel. WorkUnitServer: A WorkUnitServer represents a Server that has the same ServiceTime for all Workloads. WorkUnitServiceRequest: A WorkUnitServiceRequest specifies the number of visits to a WorkUnitServer. Attributes: ArrivalRate: The average rate at which transactions or jobs arrive from the outside world, receive service, and exit. ArrivesAt: The Name of the SoruceNode of an OpenWorkload. DepartsAt: The Name of the SinkNode of an OpenWorkload. FromNode: The Name of the origin Node of an Arc. NumberOfJobs: The fixed population that circulates among the Nodes. NumberOfVisits: The average number of visits to a Server in a ServiceRequest. Quantity: The number of instances of a given Server. Multiple servers have one queue for service requests. SchedulingPolicy: The policy used to select the next ServiceRequest to be served from a queue. ServiceDemand: The total demand for a service request. Demand is the product of ServiceTime and NumberOfVisits. ServiceTime: The amount of time required for a server to perform one unit of service. A unit of service is the amount provided for each visit to the Server. ThinkTime: The average interval of time that elapses between the completion of a transaction or job and the submission of the next transaction or job. TimeUnits: The unit of time specified in a ServiceRequest or Workload intensity. If time units are omitted, all specifications are assumed to be the same relative units. ToNode: The Name of the destination Node of an Arc. TransitType New Optional Attribute: NewWorkloadName: If this attribute appears in means that the WorkloadName changes when the transition occurs. So, the WorkoadType can also change.