SLAs are important in the fact that they provide a means in the context of service 

management to formally define the behavior and quality of the service being delivered. It 

can also include details on performance monitoring and reporting of the service being 

delivered, as well as actions to be taken when performance or availability do not meet the 

levels specified in the SLA. 

SLAs until recently, often concentrated on addressing availability and customer support 

guarantees, such as guarantees on helpdesk problem resolution time on service outages. With 

the proliferation of service outsourcing, where an organisation outsources all or portion of a 

service to third party vendors, the organisation will usually require guarantees on the 

performance and availability of the service that has been outsourced.  

One of the reasons performance has become a critical factor in Web delivered services is the 

fact that the Web is based  best effort  mechanisms of the Internet and the components in 

the delivery chain so QoS has become of critical importance. Generally the issue with web 

based service is application burnout where the service simple slows down to the extent that 

users can't utilise the service anymore [13]. 

2.4.2 SLA Negotiation 

 SLA negotiation takes place between customers and Service Providers during service 

ordering. It enables the Service Provider and customer to formally and legally state the 

responsibilities of each with regard to the service(s) being ordered by the customer from the 

Service Provider 

 [14]. 

There can be a variety of types of SLA negotiation. In the case of on line negotiation, the 

interaction to formalise the specification of the SLA could be done via a web front end that 

generates the appropriate SLA. Off line negotiation would involve person to person 

communication, such as telephone, meetings, etc. On line SLA negotiation is more 

applicable for pre defined services where the customer can fill in a template on line. Off line 

negotiation is more likely to be required for more complex services [14]. 

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