CDPD: Protocol Stack
follows OSI stack
CDPD basically specifies physical layer and data link
layer protocols only
nominal channel rate: 19.2 kbps, maximum throughput
after coding & framing, ignoring contention, is 11.8
kbps on downlink (to mobile), 13.3 kbps on uplink
standard specifies support for CLNP (ConnectionLess
Network Protocol) and IP (Internet Protocol) at layer 3
higher layers can be TCP or TP4
CDPD also specifies a wide variety of upper-layer
protocols (directory management, electronic messaging,
etc.), based on OSI and Internet services