Rockwell Automation 1771-DMC_DMC1_DMC4_DXPS Control Coprocessor User Manual - Manual (Page 101)

Chapter 6
Using the Ethernet Interface
6-20
Analogy to Client/Server Application
A simple analogy to the client/server application is the
time-and-temperature service that is provided by the local telephone
company. To acquire the time and temperature, you:
look up time and temperature in the telephone directory
dial the number
receive an announcement of the time and local temperature
hang up the telephone
The following flow chart shows a client/server analogy to the
time-and-temperature operation.
Purchase Phone Service
socket ( )
Look up phone number
gethostbyname ( )
Look up the extension
getservname ( )
Dial phone number and extension
connect ( )
Listen to the announcement
recv ( )
DoneĊhangup
shutdown ( )
close ( )
Client
Purchase Phone Service
socket ( )
Put phone number in book
bind ( )
Buy equipment to announce time
and temp, connect it, set to auto
answer number
listen ( )
If not busy announcing,
answer phone
accept ( )
Announce time
send ( )
DoneĊhangup
shutdown ( )
close ( )
Server
Wait for next call