 by masking the complexities and potential inaccuracies in provisioning through a CLI. To be fair, such functionality is no longer unusual. It would be a brave OSS vendor who lumped a service provider with nothing but a command line interface with which to provision new services. 6.11 CallGate Service Provisioning Functionality CallGate is a mediation device and multi-filtering tool. CallGate filters switch-related data to and from GSM and analogue switches. Fulfilling a typical mediation role, it acts as an interface between switches and data destinations such as billing systems. CallGate functionality includes service provisioning of network resources such as switches. Figure 6.10 describes the general setup in which CallGate is usually installed. Service provisioning commands are received by the CallGate server from the cus- tomer care layer. The commands are converted into the format(s) required by the switches and devices which must receive provisioning commands in order that the service be activated. In the case of service provisioning towards a switch, CallGate typically uses MTP/CMISE. The protocols that are recognised by network devices are an ongoing difficulty faced by OSS vendors, since there can be various old and exotic equipment in any network and such equipment may only recognise some non-standard proprietary protocol. If the software of a particular vendor does not support that protocol, then often the OSS software product will have to be extended by the vendor in order to support the protocol. Customer layer billing system Network management layer service other provisioning system system Network layer switch switch switch Figure 6.10 CallGate general setup. 6 Service Provisioning and Activation Service provisioning information is received by the centralised server (informa- tion from customer care or billing system). If necessary, the information is split and forwarded via the LAN/WAN to each CallGate satellite. Each CallGate satellite updates the switch connected to it while the central CallGat