s are built on top of the PDS capabilities. The PDS capabilities can be deployed without the multi-media session capabilities. In addition there are network entities that are common to both subsystems. The network entities are represented by squares and rectangles; the interfaces between network entities are reference points identified by numbers. MMD Core Network is identified by the shaded network elements and reference points. Figure 9.5 shows the entities that comprise the multimedia session capabilities of an All-IP network. Figure 9.5 also include several reference points that have dual labels since the standard has used (for some unidentified reasons) both labels in the specifications [7]. These entities are known collectively as the IP Multimedia Subsystem (IMS). Most of the IMS service control layer components exist in the MMD service control layer as well with the same functionality. However, there are a few differences Next Generation Mobile Communications Ecosystem in the two architectures. "IP Multimedia Subsystem" is identified by the shaded network elements and reference points. AAA: cdma2000 devices are authenticated by the AAA server. HSS includes the AAA and its associated databases. AAA functionality is enhanced in MMD to provide location management and mobility management for an entire set of services. PDE: The MMD network defines the Positioning Server and Position Determination Entity (PDE) to determine the subscriber's location. IMS in Other Standard Bodies In addition to 3GPP and 3GPP2, other standard bodies are also playing a significant role in the spread of IMS or MMD. As stated earlier, IMS is based on SIP which is standardized in IETF (Internet Engineering Task Force). The 3GPP specifications define the basic call control protocol aspects and emphasize especially the differences to the IETF SIP protocol. TISPAN (Telecommunications and Internet Converged Services and Protocols for Advanced Net- works) reuses the 3GPP IMS for its next generation network (NGN) specifications, which enabl