Enabling decentralised management through federation

Abstract

Cross-domain management is an increasingly important concern in network management and such management capability is a key-enabler of many emerging computing environments. This paper analyses the requirements for management systems that aim to support flexible and general capability sharing between autonomously managed domains. It introduces a novel Layered Federation Model (LFM) to structure this requirements analysis and describes the Federal Relationship Manager (FRM) which instantiates several layers of this model. The FRM combines semantic mapping management and authority management technologies to help solve several of the general management problems that are encountered whenever organisations enter into capability sharing agreements. An overview of related work on federation and the technical underpinnings of our approach are discussed and our work’s particular relevance to real world problems is explained through two service-centric use cases which involve the end-to-end delivery of a multimedia stream to a user’s home across several independent operators. Finally, experimental results are presented to highlight the practical advantages of our approach.

Introduction

The emergent challenge of planetary scale IT infrastructures that blend and shape networks, services, smart devices and sensors is one of heterogeneity driven not primarily by technological factors but by organisational diversity. The always-on, multi-mode, loosely-coupled, user-centric nature of modern communications and the diversity of operator business models ensure that end-to-end service provision frequently crosses heterogeneous management domains. Increasingly the service delivery path incorporates non-traditional communications resources, such as devices in a consumer’s Home Area Network (HAN), which are highly unlikely to be managed resources in the sense of supporting traditional OAM (Operations, Administration and Maintenance/Management) models, interfaces or inter-operator legal frameworks. New resources also exhibit a daunting diversity and dynamism compared to more tightly-controlled, vertically-integrated, operator-bundled consumer offerings of the past.

The modern operator landscape presents an increasingly complex topology of organisational forms. Companies are often embedded within complex webs of relationships with suppliers, collaborators, peers, competitors and a variety of other third parties. These broader organisational forms are described variously as ‘supply chains’, ‘virtual organisations’, ‘value networks’, ‘collaborative business networks’ and other subtly variegated descriptive terms. While the significance of any particular cross-organisational model in this taxonomy of organisational forms as discussed in the business management literature (e.g. [10]), is open to debate, the increasing importance of management approaches which cross-organisational boundaries and attempt to apply coherent solutions and management models across multiple independent organisations is clear.

The challenge does not only lie in the technological aspects of enabling cross-domain communication. Advances in standardised technologies such as Service Oriented Architectures (SOA), drawing on older technologies such as RPC and Component-Based Software Engineering (CBSE) models, provide easy-to-use plumbing to physically access services in other domains, in a secure and auditable manner. However, these approaches require extensive pre-negotiation and advance coordination. The fundamental problem being addressed here is how to support more agile and dynamic creation of cross-domain organisational agreements to enable capabilities to be shared between parties. Of particular importance is the problem of managing access between diverse systems to support fine-grained sharing of capabilities, through the lifecycle of the agreement. Another major issue is one of semantic interoperability (rather than data-level or network-level interoperability). Even where semantic web services [35] are used to facilitate semantic descriptions of services, the semantic descriptions must be compatible and pre-agreed. Where technologies like CMDBf [11] can provide a federated view of heterogeneous data-stores, the identification of capabilities to share, and management of access to them is still a major overhead in creating and maintaining such agreements.

Mature approaches to systems and telecommunications management such as ITIL®¹ or eTOM² have always been driven by both the technological and organisational challenges of the domain. However, despite long established signalling and media interconnects between operators supported by standardised protocols, SLAs and legal agreements, progress on B2B interfaces at the operational level has been limited [24]. One of the reasons for this is the costly and limited integration of modern OAM systems even within a single operator network due to the proliferation of vendor, FCAPS³ functional or network type stovepipes within a domain [25]. This leads to high integration costs and inflexible, brittle systems. Even agile mechanisms to dynamically define contracts and SLAs between organisations (e.g. [20]) require shared infrastructure and common semantics, and are limited to relatively static, course-grained, producer–consumer style relationships. The emergence of new types of distributed systems – autonomic, mobile and planet-scale networked applications has, if anything, served to further increase the focus on managing applications that cross-domains of authority. Innovative operators and equipment vendors have embraced this trend with a plethora of new open service APIs for the network, e.g. Alcatel-Lucent’s OpenAPI, GSMA OpenAPI and Ribbit, but it is unclear how or if these efforts will support multi-operator service and network management beyond critical functions such as billing or how such open APIs can be leveraged in conjunction with non-traditional communications resources such as the media playback capabilities of the HAN to provide end-to-end assurance and QoE guarantees.

The focus of past standardisation has been on long-lived (typically measured in years) management systems integration supported by common resource models (e.g. the Tele-Management Forum’s SID⁴), often based on green-field assumptions and perhaps implying support for a limited and pre-defined set of specific business models (e.g. TINA⁵). In contrast, the work described here assumes that the management systems to be interconnected are already deployed and use heterogeneous resource models, that interconnection takes place in a dynamic environment where instead of extensive integration, minimal and appropriate integration for the current task is negotiated by management systems as part of a wider “federation” of co-operating systems delivering end-to-end services. In this work, the term federation is employed as a general term for describing agreements that support cross-organisational capability sharing (as explained in Section 3.1). Thus, defining mechanisms for the establishment of a common semantics for describing management capabilities and communications resources is given much more weight than building yet another “common” resource model. To enable the distributed delegation of local configuration, service execution or monitoring capabilities a rule or management policy-based approach is used for the exchange of management requests. The goal of this research, from a business point of view, is to provide a lightweight relationship-management infrastructure which can conveniently support whatever business models and pricing/billing mechanisms are agreed between the participating organisations.

This research builds upon the authors’ previous work in developing decentralised policy based management systems [18], semantic mapping [51] and ontology-driven data integration [7]. The key innovations introduced in this paper are: a novel layered federation model which partitions the important aspects of inter-organisational relationships into six distinct aspects, each of which maps neatly to a technological platform that enables convenient implementation; an approach to describing shared capabilities with RDF [46] that allows deterministic management rules to be applied on top of an open and extensible RDF graph; a FRM architecture which brings this work together by combining semantic mapping management and authority management in a unified system that helps solve several of the general management problems that are encountered whenever organisations enter into resource sharing agreements. The rest of this paper is structured as follows: Section 2 provides an overview of related work on federation and the technical underpinnings of our approach; Section 3 describes two service-centric use cases for operator – HAN owner federation to capture system requirements from which a general layered federation model is derived; Section 4 presents our current work on a “federal relationship manager” that implements a sub-set of the layered federation model functionality and presents some experimental results; Section 5 describes our conclusions and plans for future work.