Operating Principles And Configuration; Saf Operation With Extension Radios; Simple Extended Saf Network - GE TransNET 900 Reference Manual

9.0 OPERATING PRINCIPLES AND CONFIGURATION

9.1 SAF Operation with Extension Radios

The Store-and-Forward (SAF) capability operates by dividing a network into
a vertical hierarchy of two or more sub-networks. (See
Adjacent sub-networks are connected via Extension radios operating in
" " which move data from one sub-network to the next one.
MODE X
The Store-and-Forward implementation adheres to the general polling princi-
ples used in most multiple-address systems (MAS). Polls originate from the
Master station, broadcast to all radios within the network, and travel hierar-
chically downward. All Remotes will hear the same message, but only one
Remote will respond. Messages within a hierarchy only travel in one direc-
tion at a time.
Using SAF will cut the overall data throughput in half, however, multiple
networks can be inter-connected with no additional loss in network
throughput.

Simple Extended SAF Network

The following example depicts a two-level network utilizing a single Master
(M) and an Extension (X) radio. See
R
J
Figure 17. Simple Extended SAF Network
In this network, messages directed to Remotes in the "K" sub-network, will
be relayed through Extension radio X
from a Remote in sub-network "K" will pass back through Extension radio
X to the Master M
j,k
frequencies and sub-network "K" but with a different radio-frequency
hopping pattern.
In the SAF operation, the Extension radios are set to
(Details Page 36) and operate with a "dual personality"—50% of the time it
serves as a Remote station and 50% of the time as a Master for sub-network
Remotes.
52 MDS TransNET Ref. Manual
Figure
M
J
R X
J J,K
R R
K K
Networks: J and K
. Radios in sub-network "J" operate on the same set of
j
17.
Invisible place holder
Sub-Network "J"
R
J
Sub-Network "K"
R
K
to the K-Remotes. Any response
j,k
MODE X
MDS 05-2708A01, Rev. F
Figure 5 on Page 4.)