Towards P2P-based Computer Network Management *

Towards P2P-based Computer Network Management * Hui Xu, and Debao Xiao Department of Computer Science, Huazhong Normal University Wuhan, P.R. China, 430079 xuhui_1004@hotmail.com Abstract Nowadays, the rapid development of computer networks calls for highly distributed management technologies that aim at integration and automation. This paper then gives an overview of current management architectures for computer networks, and tries to apply P2P technologies to make up existing limitations in term of performance, scalability, flexibility, maintainability and reliability. Due to their characteristics, P2P technologies provide a prospective approach to implement inter-domain network management, moving towards cooperative management. Performance issues show that, appropriate manipulations especially by means of compressing the P2P traffic and P2P messages, are of great significance in utilizing P2P technologies for computer network management. Keywords: Computer Network Management, P2P 1. Introduction Research and standardization of computer network management started in the late 1980s, and until now there have been several solutions. SNMP-based manager-agent management solution is the de facto criterion, which is still widely used in the industry field, but provides inadequate coverage of the five functional areas specified by OSI as Fault, Configuration, Accounting, Performance, Security (FCAPS) model [1], which defines network management as consisting of these five functional areas for management, and has a scalability problem as network size increase. With the rapid development of computer networks, integration and automation has been two main trends for their management. On one hand, more attention is paid to XML-based solutions, which focus on the improvement of SNMP in configuration management and integration with SNMP, aiming to standardize management information definition, access, and so on. In particular, as a standard based on XML, Web Services seem to be also appropriate for network management. On the other hand, Semantic Web and its main component Ontology, have emerged as another widespread technology and are currently under review in computer network management domain. Simply speaking, semantic solutions emphasize the use of ontologybased approaches, whose motivation is automation. However, nearly all the solutions available have limitations in term of performance, scalability, flexibility, maintainability and reliability [2], thus fail to keep pace with the changing requirements of the industry, especially for the management of well self-organizing distributed networks. These days, due to their characteristics, P2P technologies may be * This paper is an extensive version of the presentation titled On Network Management Solutions and the Potential of P2P Technologies at 2nd International Conference on Future Generation Communication and Networking. 25

promising in the field of computer network management. The aim of this paper is then to discuss related issues towards P2P-based management for computer networks. The remainder of this paper is organized as follows. Existing architectures for computer network management are briefly summarized in Section 2. And in order to make up their limitations, P2P technologies are introduced in Section 3. Sequentially in Section 4, integration of P2P-based network management with other solutions and its automation promoted by policies and the policy adaptation mechanism are respectively demonstrated. Some performance issues are explained in Section 5. We conclude our paper and prospect future work in Section 6. 2. Network management architectures 2.1. Protocol-based manager-agent model Figure 1 describes the manager-agent model, which defines the principles of operation for protocol-based management solutions [3]. As is depicted in Fig. 1, managed resources are modeled as Managed Objects (MOs). Typical examples for this manager-agent model are Open Systems Interconnection - System Management (OSI-SM) and Simple Network Management Protocol (SNMP). OSI-SM may be the most powerful technology for network management up to now, but is both complicated and expensive and relies on Open Systems Interconnection (OSI) protocols that have gone out of fashion, while SNMP is a popular solution that has been used by most of the industry but fell victim to its own simplicity, since SNMP has been used mostly in monitoring for fault and performance, providing inadequate support of the OSI FCAPS model. Furthermore, SNMP fails to be an interoperate solution and leads to difficulties in interdomain cooperative management. Figure 1. The protocol-based manager-agent model 2.2. Policy-based network management framework Figure 2 presents the policy-based network management framework provided by Internet Engineering Task Force (IETF) [4]. As is displayed in Fig. 2, this IETF framework contains three parts: a dedicated policy repository, Policy Decision Points (PDPs) and Policy Enforcement Points (PEPs). Policies stored in the repository are distributed to PEPs by PDPs. In essence, this policy-based network management framework reveals one key point, which is the unification of both centralization and distribution. Centralization means that it can manage computer networks as a whole, providing a consistent network behavior, higher reliability and higher efficiency. Distribution indicates that the management functions are distributed to every PDP, avoiding a heavy traffic caused by management. 26

Figure 2. IETF policy-based network management framework 2.3. Management by Delegation The approach of Management by Delegation (MbD) is to dynamically distribute the management computations to MbD-servers (elastic processes customized for network management that provide efficient bindings to management instrumentation) at the devices where the managed resources are located [5]. And MbD has been implemented in different management environments, such as MbD via SNMP [5] [6] and MbD in Common Object Request Broker Architecture (COBRA) [7], and represents an important thinking for integration with existing network management technologies. 2.4. Management using Web Services As an integration of Web and XML, Web Services have emerged as one of the promising technologies for network management, since it provides a distributed processing environment with the advantage that they are based on popular technologies [8]. When applying Web Services to manage computer networks, Web Services Description Language (WSDL) and Simple Object Access Protocol (SOAP) over HyperText Transfer Protocol (HTTP) are utilized to provide the capability for the standardizations of management information definition and access [9] [10], and based on this, Web Services become one of the dominant technologies to access and perform operations on managed resources. 3. Potential of P2P technologies for computer network management P2P networks [11] are overlay networks composed of peers located in the edges of the Internet, and P2P characteristics mainly include self-organization, symmetric communications and distributed control. It seems that P2P-based network management may be the very solution, which enables both distribution and scalability. As is stated in [12], P2P systems and network management are usually related to each other because the traffic loads of P2P systems have to be controlled to avoid regular network services becoming unavailable due to network congestion. Figure 3 gives a P2P-based network management scenario using MbD provided by Reference [13]. As is demonstrated in Fig. 3, P2P-based network management usually contains the following three entities. (1) Top-Level Manager (TLM), which is a peer that is in charge of both reacting to the requests from human operators and communicating with other management peers for the accomplishment of a particular management task. 27

(2) Mid-Level Manager (MLM), which is a peer that is responsible for reacting to the requests from the TLM and other MLMs. (3) Agent, which is software that takes charge of treating requests and responding to them. Figure 3. A P2P-based network management scenario using MbD It can be seen from above that, P2P technologies make inter-domain network management sensible and feasible, while motivate the development of cooperative management when facing heterogeneous networks. This remarkable advantage makes the P2P-based solution rather distinctive from traditional solutions for network management. Of course, P2P technologies may do more than that. Reference [12] discusses application of P2P technologies to reliable management message exchange (about how P2P-based application layer routing can improve connectivity between management entities) and load balancing of management tasks (about how groups of peers can be used to process management tasks in a balanced way) in the scope of computer network management. To sum up, all these characteristics of P2P technologies direct a promising vision for computer network management. 4. Application of P2P technologies to manage computer networks 4.1. Integration with other network management technologies A P2P-based network management solution is not like most of current solutions, since the relationship between P2P technologies and existing technologies are improvement, not replacement like that occurs between developing technologies and developed ones in most cases. This fascinating feature of P2P-based computer network management lies in the fact that it aims to reform existing solutions, making its integration with other solutions possible and rather convenient. Let us take SNMP for example. SNMP-based manager-agent network management solution is still extensively adopted in the industry field. Each SNMP-based agent usually manages a single domain. Figure 4 proposes the use of P2P technologies to manage SNMPbased agents from multiple domains. As is illustrated in Fig. 4, SNMP-based inter-domain network management becomes practicable through the use of P2P technologies. 28

Figure 4. Application of P2P technologies to manage SNMP-based agents from multiple domains 4.2. Automation based on policies and the policy adaptation mechanism Now that it is possible to make use of P2P technologies to integrate with available network management technologies, automation needs to be seriously regarded so as to specify management behaviors in P2P environments. As for this purpose, policies may be a good choice. In the IETF policy-based management framework, PDPs can be easily extended to meet the scalability requirements, with PEPs deployed in network devices. Figure 5 recommends a hierarchy P2P management model using policies and policy adaptation. Figure 5. A hierarchy P2P management model based on policies and the policy adaptation mechanism As is shown in Fig. 5, in order to support P2P-based cooperative management, various policy agents are equipped to manage all the network devices, by extending the IETF framework for policy-based network management. At the highest level, the Global Policy Agent (GPA) manages multiple Domain Policy Agents (DPAs). At the domain level, a DPA manages multiple PDPs. This domain-based partition makes it efficient to manage computer networks of different domains at the same time by one GPA. Thus in this way, the proposed hierarchy model provides a flexible management for computer networks, since it allows dynamic insertion of new management functionality. And 29

due to the requirements for automation, the policy adaptation mechanism is also introduced into this model. As is illuminated in [14], the term policy adaptation is used to describe the ability of the policy-based management system to modify network behavior in one of the following ways: 1 Adaptation by runtime modification of policy parameters; 2 Adaptation by dynamically selecting and enabling policies from a set of policies; 3 Adaptation by learning which are the most suitable policy configuration strategies from the system s behavior. Reference [14] focuses on the first two categories of policy adaptation. And Reference [15] analyzes the drawbacks of these two categories and proposes a policy adaptation approach to implement the third category by posing it as a problem of learning from current system behavior and using the results of this learning process to assemble new policies at runtime. In brief, the policy adaptation mechanism aims in transforming a new objective into a policy with minimal or no intervention of the human operations, which provides a prospective way to automate network management using P2P technologies. 5. Performance issues When employing a particular technology to manage computer networks, additional management expenses always need to be taken into consideration. And although P2P improves connectivity between management entities, it may also impact management performance [12], which primarily contains the following two factors. 1 Network usage, which is the bandwidth consumption required for management; 2 Operation delay, which is the time spent in pretreatment, execution and result retrieval. According to the experiment results presented in Reference [12], it seems that P2P has a higher traffic than SNMP and performs better than SNMP. Another performance evaluation that compares Web Services with SNMP in an MbD environment [16] shows a similar problem about high bandwidth consumed by distributed management technologies for traffic cost and message treatment. Thus we argue that, appropriate manipulations (especially compression of the P2P traffic and P2P messages) are quite important to make full use of P2P technologies for the management of computer networks. 6. Conclusions and future work This paper analyzes the evolution of network management architectures, and in order to make up their limitations, proposes the application of P2P technologies to manage computer networks, especially for the sake of inter-domain cooperative management. As is implied in this paper, P2P-based network management is a fundamental more than a technology, which facilitates integration and automation in the interest of satisfying management requirements of highly distributed networks to the utmost extent. And this paper is only the first step towards P2P-based computer network management. Future work includes 30

(a) formalization of P2P management policies and implementation of policy adaptation, and (b) security considerations for application of P2P technologies to manage computer networks. 7. Acknowledgement This work has been partially supported by the Key Scientific and Technological Project of Hubei Province, P.R. China under Grant No. 2004AA103A01. References [1] L. Raman, OSI Systems and Network Management, IEEE Communications Magazine, vol. 36, no. 3, IEEE Press, New York, 1998, pp. 46-53. [2] M. Parker, et al., Towards a Framework for Network Management Applications Based on Peer-to-Peer Paradigms, Proceeding of 10th IEEE/IFIP Network Operations and Management Symposium, IEEE Press, New York, 2006, pp. 1-4. [3] ISO/IEC 10040, Information Technology -- Open Systems Interconnection -- Systems Management Overview, ITU-T Recommendation X. 701, 1998. [4] R. Rajan, D. Verma, S. Kamat, E. Felstaine, and S. Herzog, A Policy Framework for Integrated and Differentiated Services in the Internet, IEEE Network, vol. 13, no. 5, IEEE Press, New York, 1999, pp. 36-41. [5] G. Goldszmidt, Distributed Management by Delegation, Doctor Thesis, Columbia University, 1996. [6] G. Goldszmidt, and Y. Yimini, Delegated Agents for Network Management, IEEE Communications Magazine, vol. 36, no. 3, IEEE Press, New York, 1998, pp. 66-70. [7] A Keller, Service-based Systems Management: Using CORBA as a Middleware for Intelligent Agents, Proceeding of 7th IFIP/IEEE International Workshop on Distributed Systems: Operations & Management, 1996. [8] H. Xu, and D. Xiao, Applying Semantic Web Services to Automate Network Management, Proceeding of 2nd IEEE Conference on Industrial Electronics and Applications, IEEE Press, New York, 2007, pp. 461-466. [9] T. Drevers, R. Meent, and A. Pras, Prototyping Web Services based Network Monitoring, Proceeding of 10th Open European Summer School and IFIP WG 6.3 Workshop, 2004, pp. 135-142. [10] J. Sloten, A. Pras, and M. Sinderen, On the Standardisation of Web Service Management Operations, Proceeding of 10th Open European Summer School and IFIP WG 6.3 Workshop, 2004, pp. 143-150. [11] D. S. Milojicic, et al., Peer-to-Peer Computing, Technical Report HPL-2002-57, HP Laboratory, 2002. [12] L. Z. Granville, et al., Managing Computer Networks Using Peer-to-Peer Technologies, IEEE Communications Magazine, vol. 43, no. 10, IEEE Press, New York, 2005, pp. 62-68. [13] A. Panisson, D. M. Rosa, C. Melchiors, and L. Z. Granville, Designing the Architecture of P2P-Based Network Management Systems, Proceeding of 11th IEEE Symposium on Computers and Communications, IEEE Press, New York, 2006, pp. 69-75. [14] L. Lymberopoulos, et al., An Adaptive Policy based Management Framework for Differentiated Services Networks, Proceeding of 3rd IEEE International Workshop on Policies for Distributed Systems and Networks, IEEE Press, New York, 2002, pp.147-158. [15] N. Samaan, et al., An Automated Policy-Based Management Framework for Differentiated Systems, IEEE Journal On Selected Areas In Communications, vol. 23, no. 12, IEEE Press, New York, 2005, pp. 2236-2247. [16] T. Fioreze, L. Z. Granville, M. J. Almeida, and L. R. Tarouco, Comparing Web Services with SNMP in a Management by Delegation Environment, Proceeding of 9th IFIP/IEEE International Symposium on Integrated Network Management, IEEE Press, New York, 2005, pp. 601-614. 31

Authors Hui Xu is a PhD candidate in Department of Computer Science, Huazhong Normal University, Wuhan, P.R. China. From this university, she received a B.Sc. in Computer Science and Technology, and a M.Sc. in Computer Application Technology. Since 2006, she has been a certified computer system analyst in P.R. China, working for Institute of Computer Network and Communication, Huazhong Normal University, Wuhan, P.R. China. She became a Student Member of Institute of Electrical and Electronics Engineers (IEEE) in 2007, a Student Member of Association for Computing Machinery (ACM) in 2007 and a Student Member of China Computer Federation (CCF) in 2008. In April 2008, she was awarded by International Association of Engineers (IAENG) for her first-authored paper presented to 3rd IAENG International Conference on Communication Systems and Applications. In July 2008, her biography was selected for inclusion in the 26th edition (2009) of the Marquis Who s Who in the World, California, USA. Additionally, she was also a Session Co-Chair for 2nd&3rd International Conference on Computer Science and Education (ICCSE 2007&2008), a Session Chair for 1st International Symposium on Electronic Commerce and Security (ISECS 2008), and a Paper Reviewer for 4th IEEE Conference on Industrial Electronics and Applications (ICIEA 2009). Currently, her research interests include network management, network security and related data/information/knowledge modeling. Debao Xiao is a professor in Department of Computer Science, Huazhong Normal University, Wuhan, P.R. China. He is also the director of Institute of Computer Network and Communication, Huazhong Normal University, Wuhan, P.R. China. Over the last 15 years, he has led the design and implementation of network management agents and system software for various requirements based on SNMP and XML. Currently, his research interests include computer network and communication technology, network management, network security and protocol engineering. 32