In this chapter, we use the very high level approach of Open Distributed Systems modeling to look at Network Management. We choose this high level approach here, since there is a great deal of material available on the lower level aspects of network management. In other chapters, we have already looked more closely at lower level, engineering aspects of other applications of Distributed Systems. For example, network managment standards cover the defintion of managed objects, and the standard interfaces to management agents (or servers) through SNMP or CMIP, and using ASN.1. Many network management standards include mechanisms to deal with heterogeneity, such as <#2212#> proxy<#2212#> servers and remote access to different protocols through translating gateways such as the <#2213#>em rmon<#2213#> or remote monitoring. What is not specified by network management standards is precisely the nature of the distribution of funcationality. In fact, from all the standards it would appear that a first cut at how to build a management application would be essentially centralised. There is a clear need for an Open Network Management Architecture. Networks are becoming very widespread, and heterogeneous, and it is becoming vital to control and make them useful as they evolves. The model of an open network that admits of multiple providers and multiple subscribers, arbitrarily nested, provides Virtual Private Networks. The Internet is a very good example of a VPN. Another type of VPN commonly found is the so-called Enterprise Network, used by many large corporations to connect together different services (ranging from teleophony through to data) at different sites, but drawing transmission capacity (and switching, and possibly other services) from Public Network Operators. There are two ways that ODP can inform network managements. Firstly, ODP modeling can be used to design the management functions. We look at this when applied to VPNs in the first part of this chapter. Secondly, we can use ODP (for example through CORBA) to implement service management directly. This has several advanatages over simply enhancing existing network management platforms that are based on CMIP or SNMP, espcially when applied to telecommuncaitions networks such as the Plain Old Telephone Service or the ISDN. In particular, the creation of new services becomes a matter for software, and is not the tremendously complex task that it is now. To see how hard it is in monolithic systerms, you need only look at the compleixty of adding the simplest services in so-called ;SPM_quot;Intelligent Networks;SPM_quot; that are being slowly provided in telephone systems - the effort to deploy something as easy as call forwarding, or number portability across providers is astounding. An Open Network Management Architecture (see #fn91#2214>) must address the following requirements: The working definition of an Architecture (taken from the UK ANSA work[#APM##1#]) is an engineering discipline of design with a <#2219#> common framework<#2219#> and a consistency of style. The following is a review and a synthesis of the description of the functions and conceptual architecture which fully identify the problem space.