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• Entry Channel Mode - This is the same as Dynamic Cycle, except that as
The important thing to understand about "Bytes in Queue" is that any data that
is not transmitted (i.e. does not fit) in the next slot will be reported again in the
next STDMA ACK. Thus the "Bytes in Queue" is not necessarily an accurate
measure of the actual traffic being passed through the Remote.
The "Queued Bytes" on the other hand, reflects only the data that was received
in the last cycle and thus is never duplicated (not including TCP retransmis-
sions). This is the metric that is used for computing average load and initiating a
load switch as needed.
Before discussing how load switching is determined, it is necessary to explain
the modem/router parameters that control the switch. The screen shown in
figure B-1 shows the entries in the Automatic Switching menu at the Hub that
are used to control load switching.
• Auto Switching - This is a Vipersat Feature which is enabled in the CDM
A p p e n d i x
A u t o m a t i c S w i t c hi n g
B -
size and the remaining bandwidth is distributed amongst Remotes that
have been assigned a GIR rate. This approach is based on the assumption
that Remotes that have been assigned a GIR are paying a premium and
should benefit from available excess bandwidth when needed.
Note that the GIR allocations are restricted so that the assigned GIR totals
cannot exceed available bandwidth. If this restriction is somehow violated,
then it will not be possible to properly allocate bandwidth when the
network is overloaded.
soon as the Hub receives an STDMA ACK, it initiates a switch to SCPC
mode based on the policy set for that Remote.
Figure B-1
Features Menu. If Auto Switching is not enabled, Load Switching will be
ignored.
Auto Switching menu (Hub)
L o a d S w i t c h in g
B-5
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