R&S M3SR 4100 Series, Operating Manual

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Operating Manual 6175.4760.02 – 01 5.49
M3SR Series 4100 FastLink Mode (FLM)
FLM Re-Connect Delay
In case a connect request failed, the application must wait for the specified time (in seconds)
before issuing another connect request. This is required in order to avoid/greatly reduce the
risk of concurrent connect requests from several radios at the same time. It is recommended
to use the trap feature for this command in order to get instantly updated about changes to
this parameter.
FLM Message Size Threshold
Since FLM imposes some overhead (control messages), it does not make sense to use FLM
for short data transfers. Only longer transfers will benefit from the enhanced efficiency pro-
vided by FLM. The returned value (in bytes) shall provide a reference for making the decision
whether to use FLM or not for a data transfer of a specific length.
FLM Relative Idle Timeout
Returns a time in seconds that defines for how long an established FLM connection may re-
main unused until the FLM connection gets terminated automatically. An FLM connection is
considered as unused if no FLM assigned data is transferred or received. Data transfer or
reception of other data is not taken into account. It is recommended to use the trap feature
for this command in order to get instantly updated about changes to this parameter.
FastLink over Rebroadcast
The FLM feature can be used transparently in case of rebroadcast, i.e. there is no major dif-
ference in the use of FLM between a single network and a rebroadcast network topology. Of
course, the application will notice the difference in terms of longer FLM connection establish-
ment and data transmission times.
Special FLM connection states notify the application that an FLM connection is used over
Rebroadcast. The state transition from 'Connecting' to 'Rebro-Connecting' indicates FLM
connection establishment over more than one network.
The state transition into 'Rebro Busy' is followed immediately by a transition to the state 'Idle'
and indicates that a remote network (meaning not the local network in case of rebroadcast)
already has an active FLM connection and thus the connect request was denied.
During FLM connection establishment over rebroadcast, the Relative Idle Timeout (RIT) val-
ue will be updated for each remote network traversed towards the final destination. The ap-
plication should use a trap on the remote RIT command in order to get updated instantly
about changes. Also the Re-Connect Delay (RCD) value may be updated in case of Re-
broadcast und should be watched with a trap. The picture below shows an attempt of an FLM
connection establishment in a network topology with three networks A, B and C where re-
broadcast applies.