Abstract
ATM networks are currently moving from the experimental stage of test‐beds to a commercial state where production networks are deployed and operated. The ATM Forum PNNI (Private Network to Network Interface) standard introduces an architecture suited for an internetwork which, in principle, can also be used as an intra‐network nodal interface. However, the current PNNI falls short in providing an acceptable solution due to severe performance limitations in intra‐network operation, limited functionality and the lack of open interfaces for functional extensions and services.
OPENET is a common, open and high‐performance network control platform based on performance and functional enhancements to the PNNI platform. It is designed to address the issues of interoperability (being vendor independent), scalability (in terms of network size and volume of calls), high performance (in terms of call processing latency and throughput) and functionality. OPENET is mainly an intra‐networking extension to current PNNI. It is compatible with PNNI in the internetwork environment where large networks must be partitioned according to natural topological or organizational boundaries.
The major novelty of the OPENET architecture (compared to the current PNNI) is its focus on network control performance. A particular emphasis is given to the increase of the overall rate of connection handling, to the reduction of the call establishment latency and to the efficient utilization of the network resources. These performance enhancements are achieved by the use of a native ATM distribution tree for the dissemination of utilization update, light‐weight call setup, take down and modification signaling, the use of fast setup and takedown with the future option to implement them in hardware, and extensive use of caching and pre‐calculation for route computation. OPENET also extends PNNI in terms of functionality. It utilizes a new signaling paradigm that better supports fast reservation and multicast services, a rich control communication infrastructure which enables the development of augmented services leveraging the existing functions, messaging system and information of the network control platform.