**1.1 Static load balancing**

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tions of load balancer are as follows:

• Improves resource utilization

• Increases client satisfaction

resources as demand occurs

and prevents starvation [3, 4].

resources, and sends request to the server which is lightly loaded. The major func-

• Provides fault tolerance and flexible framework by adding or subtracting

To incorporate these benefits, it is important to select the suitable load balancing algorithm (LBA) for web resources in distributed environment [5, 6]. Based on a process characteristic, LBAs can be categorized in three categories as shown in **Figure 2**. Both sender-initiated and receiver-initiated algorithms use different

The load balancing algorithm (LBA) exists based on current state of the system as shown in **Figure 1**. Static algorithms require prior information about the system characteristics such as processing capability, memory, number of active connections etc., while DLB algorithms use current status of the system to make scheduling decisions. Load balancing significantly improves global system performance in terms of throughput and resource utilization. The several reasons to use LBAs are as follows: cost optimization, fault tolerance ability, system adaptability and extensibility, decreased response time, idle time of resources, increased throughput, reliability,

• Distributes incoming traffic across multiple computational resources

• Determines resource availability and reliability for task execution

**62**

**Figure 2.**

**Figure 1.**

*Classification based on System state.*

*Classification based on Process Origination.*

Static load balancing approaches use the prior information of tasks, computing resources or processing element, and network detail as shown in **Figure 3**. The task can be submitted to any processing element using two methods:


In stateless method, selection of a processing element (PE) is done without having any awareness of the system environment, while in a state-based method, selecting a PE requires information of the system condition [7]. Stateless methods are simple to implement, but it provides one-to-one interaction between the client and server at a time as shown in **Figure 4**.

**Figure 5** represents the stateful load balancing method; the load balancer keeps track for all the sessions, and decisions are taken based on server load. Various stateless techniques exist for selecting the processing element such as RR-LBA, weighted

**Figure 3.** *Static load balancing.*

**Figure 4.** *Stateless static load balancing.*

**Figure 5.** *Stateful static load balancing.*

**Figure 6.** *Dynamic load balancing.*

round robin (WRR)-LBA, and random allocation algorithm [7]. However, these algorithms have limited scope due to the dynamic nature of distributed environment.
