In recent years, mobile and fixed operators are offering broadband access to the Internet by either adding wireless access to their existing core networks (e.g., CDMA IxEVDO, GPRS, and WiFi) or continuing to evolve existing broadband infrastructures (e.g., DSL, Cable and FTTx). Consequently, IMS and MMD architectures as defined by 3GPP and 3GPP2 are becoming increasingly important to network operators, in particular, for offering ubiquitous service and seamless mobility to end users, along with management and control. Although 3GPP2 MMD architecture has adopted most of the 3GPP IMS core functionalities and interfaces, it added several other unique functional components and interfaces to fit the specific need of CDMA2000 access networks. Therefore, it is important to understand the gaps and issues associated with the 3GPP2 MMD architecture with regard to the 3GPP IMS architecture. In this paper, we first analyze the functional and protocol level differences between IMS and MMD architectures. Based on our analysis, we then articulate several deployment architectural alternatives for 3GPP2 MMD networks and finally analyze the pros and cons of each architecture.