TCP/IP Tutorial and Technical Overview - IBM Redbooks

► Client control
As owner of the gateway, it decides who gets access to the WAP domain and
who is allowed to push messages.
Overview of PPG services
The services of the push proxy gateway include:
► Push initiator identification authentication, access control
► Parsing of and error detection in content control information
► Client discovery services
► Address resolution
► Binary encoding and compilation of certain content types to improve OTA
► Protocol conversion
Access from the Internet side
PPG accepts content from the Internet side, which is divided into several parts
using multipart/related content type. The first part contains the information for the
PPG, for example:
► Recipient information
► Timeouts
► Callback requests
The PPG acknowledges the parsing of this control information. If the push
initiator requests, it can also call back a pushing server when the final status of
the push submission to the WAP client has been reached, and will report about
the status (delivered, cancelled, or expired).
The PPG pushed content delivery
PPG tries to find the correct WAP client and, if successful, delivers the content
using the push over-the-air protocol. The trial to deliver is limited by the timeout
specified for the client. This timeout can be set by the push initiator or the policies
of the mobile operator.
PPG can implement addressing aliasing schemes to enable special multicast
and broadcast functions. This requires the translation of special addresses into a
broadcast operation. The push initiator can also query client capabilities and
preferences to create a better formatted content for a particular WAP terminal.
666 TCP/IP Tutorial and Technical Overview