Demand assigned capacity management (DACM) in IP over optical (IPO) networks

The demand assigned capacity management (DACM) problem in IP over optical (IPO) network aims at devising efficient bandwidth replenishment schedules from the optical domain conditioned upon traffic evolution processes in the IP domain. A replenishment schedule specifies the location, sizing, and sequencing of link capacity expansions to support the growth of Internet traffic demand in the IP network subject to economic considerations. A major distinction in the approach presented in this paper is the focus of attention on the economics of "excess bandwidth" in the IP domain, which can be viewed as an inventory system that is endowed with fixed and variable costs and depletes with increase in IP traffic demand requiring replenishment from the optical domain. We develop mathematical models to address the DACM problem in IPO networks based on a class of inventory management replenishment methods. We apply the technique to IPO networks that implement capacity adaptive routing in the IP domain and networks without capacity adaptive routing. We analyze the performance characteristics under both scenarios, in terms of minimizing cumulative replenishment cost over an interval of time. For the non-capacity adaptive routing scenario, we consider a shortest path approach in the IP domain, specifically OSPF. For the capacity adaptive scenario, we use an online constraint-based routing scheme. This study represents an application of integrated traffic engineering which concerns collaborative decision making targeted towards network performance improvement that takes into consideration traffic demands, control capabilities, and network assets at different levels in the network hierarchy.     

MPLS and traffic engineering in IP networks

Rapid growth and increasing requirements for service quality, reliability, and efficiency have made traffic engineering an essential consideration in the design and operation of large public Internet backbone networks. Internet traffic engineering addresses the issue of performance optimization of operational networks. A paramount objective of Internet traffic engineering is to facilitate the transport of IP traffic through a given network in the most efficient, reliable, and expeditious manner possible. Historically, traffic engineering in the Internet has been hampered by the limited functional capabilities of conventional IP technologies. Recent developments in multiprotocol label switching (MPLS) and differentiated services have opened up new possibilities to address some of the limitations of the conventional technologies. This article discusses the applications of MPLS to traffic engineering in IP networks