Bhumip Khasnabish

Applications and support technologies for mobility and enterprise services [Guest Editorial]

For enterprises, large and small, mobile services are becoming increasingly critical. Companies are no longer static or bound to their office premises. Instead, they have full mobility needs, with global customers, many of them also on the move, a growing number of remote offices that need to be interconnected, telecommuters who work from home, employees that are always traveling, with longer times out of the office and in the field. The six articles in this special issue cover mobile convergent communications (IMS corporate services), mobile e-health/e-inclusion applications, networked workspaces, and mobile device collaborations.

End-to-End Network Reliability Modeling of Enterprise VoIP Services

Practical reliability models are developed to support the engineering of carrier-class networks that provide VoIP service to enterprise customers. The focus is on end-to-end measures of service reliability. The paper first describes the typical architecture of large-scale carrier-class VoIP networks, the message flows that exist therein, and use case variations that arise in practice. Reliability measures of interest are then defined and models are developed in terms of the call flows and element reliabilities. The failover and repair mechanisms that may be employed in the various protocol layers are also surveyed. An example analysis illustrates the modeling of a particular use case. The developed models provide a convenient practical means to estimate end-to-end VoIP service reliability prior to field trials or network deployments. Such proactive modeling is an important step in the planning and engineering of new VoIP networks