Patterns in SNMP-Based Management

A lot of activity is currently going on to replace the SNMP management architecture with a solution better suited to managing modern IP networks and systems. New candidates include Management by Delegation, active networks, and Web-based management. In this exercise, the management community runs the risk of throwing the baby out with the bath water by focusing too much on a few well-known problems exhibited by SNMP (e.g., its poor scalability) and neglecting most of its other characteristics, including those that contributed to its success (e.g., the reasons why it is simple). One way to avoid this is to explicitly capture the experience gained in the management of IP networks and systems with SNMP. In this paper, we make one step in this direction by studying the SNMP management architecture through a software engineers eyes: we identify in SNMP some of the fundamental architectural and design patterns defined in the literature. Patterns are schematic, proven solutions to recurring problems. By characterizing the current management architecture in terms of patterns, we help retain the strengths of SNMP-based management in future management architectures. We also make it easier for new software engineers to move to network and systems management by characterizing this application domain in standard pattern terms, as opposed to using the jargon understood solely by the SNMP community

The Push Model in Web-Based Network Management

The management of IP networks is currently based on the SNMP protocol, and the use of expensive network management platforms designed according to the manager/agent paradigm of the SNMP framework. It uses two different schemes to transfer management data: a request/response protocol for data collection and network monitoring (data polling), and unsolicited push to deliver SNMP notifications. This design is exposed to a number of problems, with regards to the time-to-market of vendor-specific management software, versioning, protocol efficiency, security, etc. In this paper, we propose a novel approach to network management based on the push model. This model is well-known in software engineering, and encountered a large success on the Web recently with the push technologies. It relies on the publish/subscribe/distribute paradigm, and uses a single scheme to transfer all management data. We describe why it is more efficient, in terms of network and systems resources, than the traditional pull model. We also explain in detail how to implement this model with Web technologies to deliver SNMP notifications, to handle events, and to distribute MIB data for network monitoring and data collection

IP Network Management Platforms Before the Web

In this paper, we analyze the characteristics and shortcomings of IP network management platforms before the arrival of Web technologies. In the first part, we give a brief history of IP network management, and summarize the limitations of traditional (i.e., pre-Web and SNMP-based) management platforms. We recall the initial objectives of open network management. We then explain how the early vision of generic management was changed by the industry`s natural inclination for market segmentation, and how the market of IP networks evolved from generic to vendor-specific equipment, management GUIs and MIBs. In the second part, we propose a simple model of traditional IP network management platforms, against which new Web-based management solutions can be compared. We introduce the three core functions of such platforms (network monitoring, data collection, and event handling), distinguish regular management from ad hoc management, and explain how SNMP`s polling model maps onto these functions

Technical Assessments of Future European Space Transportation Options

The paper describes some of the most recent activities in Germany in the technical assessment of future European launcher architecture. In focus is a joint effort of DLR-SART with German launcher industry in the definition of a next generation upper-medium class expendable TSTO with an initial operational capability after 2020. Involved companies are EADS astrium and MT Aerospace. This DLR-agency funded study WOTAN investigates fully cryogenic launchers as well as those with a combination of solid and cryogenic stages, fulfilling a requirement of 5000 kg single payload into GTO. Solid strap-on boosters should allow both versions further payload growth capability. In its second part the paper analyzes options for new liquid fuel upper stages to be put on the P80 solid first stage of the Vega small launcher. Versions with storable as well as cryogenic propellants are investigated in a preliminary launcher system lay-out and their technical viability is critically assessed