SummaryWhen looking at policies within a virtual circuit in Configuration > Optimizer, Priority is mentioned. This refers to the order in which the policies will use excess bandwidth on the virtual circuit to burst above their own guaranteed bandwidth.
OverviewWhile creating a policy, you can set its burst priority. This is displayed as Priority when you view the policies for virtual circuits in Configuration > Optimizer.
If excess bandwidth is available, the burst priority is used to decide how excess bandwidth is distributed. Policies with a higher burst priority will be preferred when allocating excess bandwidth.
VoIP has 100kbps guaranteed bandwidth, a maximum of 300kbps burst, and a Priority of 1
Netflix has 100kbps guaranteed bandwidth, a maximum of 300kbps burst, and a Priority of 2
When the virtual circuit has 200kbps to spare for burst, it will first go to VoIP. If VoIP isn't using its guaranteed bandwidth, then the 200kbps will go to Netflix. If VoIP suddenly needs an extra 75kbps, it will be taken away from the 200kbps of burst that Netflix is receiving.
Note that the burst bandwidth does not move between virtual circuits, regardless of the policies. They are contained in a single Virtual Circuit. So even if Policy A in Virtual Circuit 1 has Priority 1, and Policy B in Virtual Circuit 2 has Priority 1, they will both get the bandwidth priorities because each virtual circuit has its own bandwidth allocated.