TABLE OF CONTENTS When sending a parcel, the sender can generally select from a range of contractual commitments from the postal courier service provider; that the parcel will arrive within two working days of being sent, for example. The commitments may include other parameters or metrics such as the number of attempts at redelivery if the first attempt is unsuccessful, and any compensation that will be owed by the courier if the parcel is late or even lost. The more competitive the market for the particular service, the more comprehensive and the tighter the commitments or service level agreements (SLAs) that are offered.
In the same way, within the networking industry the increased competition between Internet Protocol (IP) [RFC791] service providers (SPs) together with the heightened importance of IP applications to business operations has led to an increased demand and consequent supply of IP services with better defined and tighter SLAs for IP performance. These SLAs represent a contract for the delivery of the service; in this case, it is an IP transport service. The SLA requirements of a service need to be derived from the SLA requirements of the applications they are intended to support; customers utilizing the service rely on this contract to ensure that they can deliver the applications critical to their business. Hence, SLA definitions are key and it is essential they are representative of the characteristics of the IP transport service they define.
For an IP service, the service that IP traffic receives is measured using...
