Cross Layer Optimization

Integrated analysis of communication networks from the IP layer to the physical (optical) layer offers a multitude of advantages over analysis of each separate layer. In terms of network design integrated analysis helps to ensure the right amount of switching resources on each layer, thus achieving best performance at minimum cost. New routing algorithms considering dynamically light path settings may make a much more efficient use of available resources, thus saving both money and energy.


  • Fulfilling of performance requirements at lowest cost
  • Building resource-efficient networks
  • Building resilient networks with the right restoration / protection mechanisms at the right layers
  • Identifying the appropriate switching layer
  • Finding the correct balance between optical and electrical switching
  • Identifying where to store and to cache data in the network
  • Identifying the necessary amount of traffic grooming

Technical Background:

Design of multi-layer networks

  • Combination of exact and heuristic methods for network planning and optimization
  • Development of efficient heuristics
  • Optical bypass

Multi-layer routing

  • Control plane development
  • Automatic set-up of light-paths
  • Constraint based routing n Energy aware routing
  • Multi-layer restoration and protection

Available tools

  • IBM ILOG CPLEX: mixed integer progamming solver
  • OPNET Modeler: an event-based simulation tool
  • Self developed programs
  • IXIA Network Testing Equipment


  • Improvement of network performance
  • Increase of network capacity
  • Reduction of network costs
  • Reduction of energy consumption
  • Cost savings up to 20% for equipment costs
  • More efficient use of network resources, by multi-layer routing schemes
  • Improved network resilience

Future Objectives

  • Design of efficient, powerful and easily manageable IP / Ethernet / WDM networks
  • Development of efficient network planning and optimization by combining heuristic and exact approaches
  • Design of transparent optical core networks
  • Design of multi-technology heterogeneous networks