Customer Service Management (CSM) offers a management interface between customer and service provider, which enables customers to individually monitor and control their subscribed service. This paper presents an approach towards the definition, implementation and instantiation of a CSM management information base for an IP connectivity service (CSMIP-MIB). The approach uses object-oriented techniques to model the CSM-IP-MIB in order to facilitate re-useability and specialization in real-life scenarios. The CSM-IP-MIB consists of four packages that reflect the relevant details of the IP connectivity service, including contracts, SLAs, topology, current and historical state of the IP connectivity, QoS parameters, QoS violations and problem management as well as authenticationand access control to provide customer-specific views. The CSM-IP-MIB is implemented using the CORBA technology, resulting in a distributed client/server application, which is being instantiated for the IP connectivity service of the German Research Network Organization.