Policies are increasingly being used to manage complex communication networks. In this paper we present our work on a "policy server" which is being used to provide centralized administration of packet voice gateways and "soft switches" in next generation circuit and packet telephony networks. The policies running in the policy server are specified using a domain independent policy description language (PDL). This paper is motivated by the problem of evaluating policies specified in PDL. We present an algorithm for evaluating policies and study both its theoretical and empirical behavior. We show that the problem of evaluating policies is quite intractable. However we note that the hard instances of the policy evaluation problem are quite rare in real world networks. Under some very realistic assumptions we are able to show that our policy evaluation algorithm is quite efficient and is well suited for enforcing policies in complex networks. These results constitute the first attempt to develop a formal framework to study the informal concepts of policy based network management.

We present the design and implementation of the network management layer (Netmon) of the SARAS softswitch developed at Bell Laboratories. The key distinguishing feature of the Netmon subsystem is that the "logic" governing the management is tailored on a per-customer basis by crafting a set of policies appropriate for the customer, and enforcing them via the system. Most such policies can be formulated as sets of low-level rules that describe how to (re)configure a device or how to manipulate the different network elements under different conditions. The system has been currently deployed to do operations, administration, maintenance and provisioning (OAM&P) in carrier-grade communication networks.

Presents first-hand experiences from an actual re-engineering project. Business re-engineering is a process affecting not only the software system involved, but the underlying business model as well. Indeed, it is the changed business model along with the new technologies that determine the design of the new system. This paper is a walkthrough of the design of PICSDESK, a prototype incorporating some modern technologies to support the old business model of its predecessor and its evolution to a new business model. PICSDESK may be thought of as an example of a new breed of inventory control systems.