An ATM Switch Control Interface for Quality of Service and Reliability

Abstract-- Traditional communication switches include an embedded processor that implements both the switch control and network signalling. Such an architecture is failure-prone due to the complexity of the control software of modern network. Recently, a new approach of controlling switches through an external controller is gaining momentum, due the flexibility and reliability it affords. In addition, open control protocols and interfaces for controlling and managing networks, are now emerging as an alternative to specifications and standards. For instance, in the OpeNet project Sun Labs has designed and implemented an open, high performance ATM network control platform. In this paper we describe the OpeNet Switch Control Interface (ONSCI)--an open local switch control protocol, for controlling an ATM switch. An ATM switch controller uses this protocol to setup or tear down virtual circuits and perform other control and management functions in an ATM switch. Important and distinguished features of this protocol are primitives for Quality of Service (QoS) management in the switch and support for fault-tolerant operation in case of failure of a switch controller. The design of these primitives is based on conceptual modeling of the switch architecture. The model is generic enough to cover a wide range of ATM switches. The other primitives for switch management and control are borrowed heavily from Ipsilon’s GSMP protocol. They include primitives for switch configuration, port and switch management, VP management and performance monitoring. The protocol was implemented and integrated with the OpeNet platform. Without going into specifics of the protocol, we describe its design principles and show how it has affected our protocol