Operators of carrier-scale IP networks are faced with the constant challenge of providing a consistent service in the most cost-effective way while dealing with rapid network expansion and traffic growth, the introduction of new services, and the deployment of new technologies. This is particularly challenging for networks that offer quality of service (QoS). Such networks support a wide range of application with very different requirements on performance. They enable customers to prioritise their applications according to performance and business need by offering multiple classes of service with different targets on delay and throughput, backed by service level agreements (SLAs) or service level guarantees (SLGs). For example, voice applications should be assigned to a high priority class to ensure the low delay and loss that is necessary for a satisfactory call quality. On the other hand, Web browsing and e-mail are usually considered to be lower priority and tolerate a 'best-effort' service. This chapter focuses on two key activities for capacity planning in which performance engineering has an important role to play. The first is the development of modelling tools that provide accurate performance prediction for a wide range of scenarios. The second is the detailed analysis of network and traffic measurements. Both are essential in achieving an optimum balance between the cost of a network and the performance experienced by the users.

Inspec keywords: IP networks; telecommunication traffic; quality of service; telecommunication network planning

Other keywords: e-mail; satisfactory call quality; Web browsing; service level guarantees; capacity planning; network expansion; service level agreements; quality of service; traffic growth; performance engineering; carrier-scale IP networks; best-effort service

Subjects: Computer communications