TCP/IP Tutorial and Technical Overview - IBM Redbooks

Example of a WSP-WTP sequence flow
Figure 18-11 depicts the flow of a primitive sequence and shows the relationship
between WSP and WTP requests and responses. The flow is based on a Class 2
transaction which, as defined earlier, is a reliable, confirmed message exchange.
Client
WSP
S-MethodInvoke.req
S-MethodInvoke.cnf
S-MethodResult.ind
S-MethodResult.res
Figure 18-11 WSP-WTP primitive sequence for request-response
The following steps describe the flow of a primitive sequence:
1. The first sequence is initiated through a client application (for example, an
inquiry for a service), which starts with a S-MethodInvoke.req operation to the
server application within a session.
2. The second sequence is a response from the server to confirm to WSP in the
client stack that the invoke message (the inquiry) has been received by the
server.
3. The third sequence returns the result request (reply to the inquiry) from the
server to the client.
4. The fourth sequence confirms the receipt to the server that the reply was
received correctly.
18.9.5 Wireless Session Protocol (WSP)
WSP, defined by the OMA WAP-230-WSP-20010705-a specification,
establishes a reliable session between the client and the server and releases that
session in an orderly manner. An illustration of a client/server session is in
Figure 18-13 on page 686. WSP session establishment agrees on a common
level of protocol functionality using the capability of negotiation. WSP exchanges
682 TCP/IP Tutorial and Technical Overview
TR-Invoke.req
TR-Invoke.cnf
TR-Invoke.ind
TR-Invoke.res
WTP
TR-Invoke.ind
TR-Invoke.res
TR-Invoke.req
TR-Invoke.cnf
Server
WSP
S-MethodInvoke.ind
S-MethodInvoke.res
S-MethodResult.req
S-MethodResult.cnf