Operational Assumptions

Mobile IP uses the Internet as an operational model. Operational assumptions for Mobile IP are the same as those for the Internet, which can best be described as ``managed chaos". On the other hand CDPD assumes a clearly defined network with well defined boundaries of authority and responsibility. The CDPD internetwork is a collection of CDPD service provider networks. Based on bilateral agreements, each Home MD-IS interoperates with various serving MD-ISs, which may be administered by various CDPD service providers. The infrastructure of the CDPD network is a closed network. This implies that some level of trust, order and accountability can be expected. ``Control and Order" expresses the general flavor of CDPD's operational assumptions. These operational assumptions had a direct impact on many of CDPD's protocol design decisions, particularly in the areas of security, manageability and scalability. Because the mobility tunnel begins and ends within the CDPD networks, to some extent it does not require the level of security that is necessary between the home agent and the foreign agent in Mobile IP.

Even though, securing the network layer of the CDPD network is not required in the CDPD specifications, the CDPD specification team recognized that providing data confidentiality and authentication for the mobility tunnel was important. Network Layer Security Protocol (NLSP), which can be considered an adjunct to CLNP, provides comprehensive security services. Unfortunately, it is a lot more theoretical than real.