Packet Data Serving Node (PDSN)

The PDSN is a new component associated with a CDMA2000 system, as
compared to cdmaOne networks. The PDSN is an essential element in the
treatment of packet data services that will be offered, and its location in the
CDMA2000 network is shown in Figure 7-2. The purpose of the PDSN is to
support packet data services and it performs the following major functions
in the course of a packet data session:
■ Establishes, maintains, and terminates Point-to-Point Protocol (PPP)
sessions with the subscriber
■ Supports both Simple and Mobile IP packet services
■ Establishes, maintains, and terminates the logical links to the Radio
Network (RN) across the radio-paket (R-P) interface
■ Initiates Authentication, Authorization, and Accounting (AAA) for the
mobile station client to the AAA server
■ Receives service parameters for the mobile client from the AAA server
■ Routes packets to and from the external packet data networks
■ Collects usage data that is relayed to the AAA server
The overall capacity of the PDSN is determined by both the throughput
and the number of PPP sessions that are being served. The specific capacity
of the PDSN is, of course, dependant upon the infrastructure vendor
used as well as the particular card population that is implemented. It is
important to note that capacity is only one aspect of the dimensioning
process and that the overall network reliability factor must be addressed in
the dimensioning process.