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SATELLINE-EASy / SATELLINE-EASy 869
User Guide, Version 3.0
73
14.3
Detailed description of Message Routing
14.3.1
Source Mode Routing
The above figure represents a network containing four (4) radio modems. Each radio modem is
given a unique address (0…3). A terminal device has been attached to the three of the four
radio modems and they communicate with each other using terminal addresses X, Y and Z,
respectively. Radio modem 0 and terminal device X together constitute the base station of the
network and all routing information of the network has been programmed into this base station.
When the terminal device X transmits a packet to (e.g.) terminal Y, radio modem 0 will detect
the address Y from the data received through the serial port. From the routing table a route 1,2
can be found to which the radio modem also adds its own address to define the route for return
data. Radio modem 1 repeats the packet and radio modem 2 removes the address information
from the received data packet thereby transferring only the original data to the serial interface.
The address information received together with the packet is reversed (2, 1, 0) and saved to be
used in the transmission of subsequent reply packets.
14.3.2
Virtual Mode Routing
Please contact SATEL for more information of Virtual Mode Routing.
14.3.3
Overhop function in Source Mode Routing
Master TD
Radio
Substation RD
M
R1
R2
S
TD
RD
t
Master
R1
R2
When using repeaters, the same packet is sent via a (radio) channel several times. A radio
modem situated in the repeater chain will often hear other radio modems in addition to the
immediate neighbouring radio modems. With
Source Mode Routing
the complete address