Controlling the Tempest: adaptive management in advanced ATMcontrol architectures

摘要

Research in ATM management has delegated control functions fromnthe ATM switch into higher level open control architectures. Fornexample, functions such as call admission control are implemented withinnsuch a control architecture rather than as an integral part of thenswitch. The association between the switch fabric and the switch controlnfunctions is made less strict, allowing, for example, a single entity tonperform routing for a group of switches. This greater flexibility in thenprovision of control is accompanied by an increase in complexitynresulting from the possibility of making control decisions remotely fromnthe controlled network element. The location of the controller innrelation to the fabric is not just an implementation issue; it has anlarge impact on the way we handle traditional operation and maintenancen(OAM) functions. For example, recovering from partial failure of thennetwork is problematic when the controlling entity is communicating withnthe switch it controls across that same network. Most research into suchncontrol architectures has concentrated on the advantages of increasingnflexibility; little work has looked at how the traditional techniquesnfor creating robust networks can be adapted for use in this environment.nMobile software agents can move to where their functions are carriednout. When an agent has moved across the network, it executes itsnfunction there. The function will not fail due to network problems. Theyncan also reduce the amount of management state that needs to be carriednacross the network for control purposes. This is important whennrecovering from failure since the network is stressed and minimalnexpectations should be placed on its behavior. We show how mobile agentsncan be used within an open control architecture in order to implementnrobust operation and maintenance functions. We explain in some detailnour work in implementing one such function