Chapter 4. Call Flow
This chapter will teach you:
How a normal Mobile IP call works
Several common error conditions and their remedies
Overview
A normal Mobile IP call involves several layered protocols. In order from lowest to highest:
CDMA2000 (itself a collection of layered protocols, but beyond the scope of the MOB-IP-SIM) specifies a radio link.
PPP, the Point-to-Point Protocol, specifies some control protocols to establish an error-controlled link, provide authentication of the mobile station, and negotiate IP parameters. In addition, it specifies how to transmit multiple protocols over a link; the only one the MOB-IP-SIM presently supports is IP version 4.
IP, the Internet Protocol, specifies a best-effort packet-switched network. IP datagrams may be delivered out of order, duplicated, or lost.
Mobile IP specifies a protocol for a mobile to register its location and get its traffic forwarded to it from its home location.
Some transport-layer protocol, such as TCP or UDP, provides demultiplexing and possibly error control to an application-layer protocol. These are beyond the scope of the MOB-IP-SIM as well.
