 has done more than any other organisation to promote the use of standard interfaces for OSS software. The TMF's next-generation OSS (NGOSS) initiative relies on XML and CORBA. At the same time, the OSS- J initiative under the auspices of the TMF and spearheaded by Sun Microsystems is based on Java. The device independence of these technologies means that they are well suited to helping achieve OSS interoperability. The wireless application proto- col (WAP) was one of the first practical technologies to be built on XML, and XML K. Misra et al. (eds.), OSS for Telecom Networks © Springer-Verlag London Limited 2004 OSS for Telecom Networks was chosen owing to WAP's purpose of allowing communication with a range of types of wireless device. Provisioning tasks that require interaction between the service provider and exter- nal organisations include: 1. provisioning of leased circuits 2. provisioning of IP components 3. interconnection requests from other operators 4. local loop unbundling requests 5. carrier preselection orders 6. number portability requests. As services become more complex (e.g. with operators using creative product design to derive return on investment in 2.5G and 3G mobile infrastructure and licences), the number of components and partners in the end-to-end provisioning process can only increase. The extensibility of XML makes it well suited to the open- endedness of the universe of future services. XML is also powerful enough to play a role in implementing policy-based management mechanisms. The need for interoperability is enhanced by the tendency for vendors in the young and innovative OSS industry to focus on different parts of the total OSS picture. For example, Clarity products are very strong in circuit design functionality whereas Cramer and Alcatel products are strong in inventory database synchronisation. Both of these functional domains are critical for trouble-free service provisioning. Thus, a carrier who wants true "best-of-breed" in each OSS functionality domain will certainly be i