Feature Description
A remote with the Idle and Dormant States feature enabled can be in one of three states: Active, Idle or Dormant. Figure 12-1 shows how the remote’s states change when this feature is enabled.
Figure 12-1. Active, Idle and Dormant State Change Diagram
Figure 12-2 shows the fields on the iBuilder Remote QoS tab used to configure this feature. The configuration of the remote’s Minimum Information Rate fields determine the system behavior in the Active State. The configuration of the Idle and Dormant States fields determine the system behavior in the other two states.
Figure 12-2. Configuring Active, Idle and Dormant States
A remote that is in network and actively transmitting upstream user traffic is in the Active State. If Minimum Information Rate is not enabled, a remote in the Active State is granted a minimum of 1 slot per frame by default. If Minimum Information Rate is enabled, then the minimum bandwidth granted to the remote is determined by the value in kbps entered on the
Feature Description
screen (Figure 12-2). Notice in Figure 12-2 that when a Minimum Information Rate is entered into iBuilder, the equivalent number of slots per frame is automatically displayed.
When you select Enable Idle and Dormant States, then for each of those states you can configure how frequently slots are allocated to the remote (in units of 1 slot per n frames) and the Timeout that determines when the remote will change to that state from the previous state.
If a remote in the Active State has no upstream user traffic to transmit for the time period defined by the Idle State Timeout, then the remote changes from the Active State to the Idle State. When the remote enters the Idle State, the remote’s Minimum Information Rate changes based on the Idle State configuration of 1 Slot / n Frames. Notice in Figure 12-2 that when you configure the Idle State for 1 slot every n frames, the equivalent Idle Minimum Information Rate is automatically displayed in kbps on the screen.
If the remote has been in the Idle State for the time period defined by the Dormant State Timeout and the remote still has no upstream user traffic to transmit, then the remote changes from the Idle State to the Dormant State. In the Dormant State, the remote’s Minimum Information Rate again changes based on the Dormant State configuration of 1 Slot /
n Frames. As with the Idle State, when you configure the Dormant State for 1 slot every n
frames, the equivalent Dormant Minimum Information Rate is automatically displayed in kbps on the screen. A remote in the Dormant State remains in that state as long as it has no upstream user traffic to transmit.
If at any time a remote in Idle State or Dormant State receives upstream user traffic for transmission, the remote returns to the Active State and the Idle State Timeout is reset. By default, only upstream user traffic triggers a state change from Idle or Dormant State to Active State. Upstream management traffic generated by the remote to the NMS does not trigger a state change. To select which upstream QoS Service Levels trigger state changes, select or clear the Trigger State Change check box for the Service Level defined for that traffic. An example is shown in Figure 12-3. (See the section titled “Adding an Application
NOTE: The Active State behavior is identical to the system behavior when the Idle and Dormant States feature is not enabled.
NOTE: Minimum Information Rate must be greater than or equal to the Idle Minimum Information Rate. Similarly, the Idle Minimum Information Rate must be greater than or equal to the Dormant Minimum Information Rate. iBuilder
enforces these constraints when the configuration is entered on the Remote QoS tab.
Feature Description
Profile” in the chapter “Configuring Quality of Service for iDirect Networks” in the iBuilder User Guide for details.)
Figure 12-3. Upstream Service Level with Trigger State Change Selected
Using the configuration in Figure 12-2 as an example, if the remote has been recently Active but has no more user traffic to transmit, it will remain in the Active State for 120 seconds (the Idle State timeout). During that time, the remote will be granted its configured Minimum Information Rate of 27.264 kbps. If after 120 seconds the remote still has no user traffic to transmit, it will enter the Idle State and the Minimum Information Rate granted to the remote will change to 3.14 kbps (or 1 slot every 8 frames).
If after 180 seconds in the Idle State the remote still has no user traffic to transmit, it will enter the Dormant State and its Minimum Information Rate will change to 0.85 kbps. The remote will remain in the Dormant State until it receives upstream user traffic to transmit. If at any time a remote in Idle State or Dormant State receives upstream user traffic for transmission, it will to return to the Active State and the Minimum Information Rate will return to 27.264 kbps.
To remain in the network, a remote should transmit at least 1 burst every 4 seconds. With a typical frame length of 125 ms, this translates into a minimum allocation of 1 slot every 32 frames.
As in previous releases, the Minimum Information Rate for the Active State cannot be set lower than one slot every 16 frames (the equivalent of one slot every 2 seconds.) Typically, this minimum allocation is sufficient for any remote to stay in the network. For the Idle State and the Dormant State, however, the Minimum Information Rate can be set as low as one slot every 64 frames (one slot every 8 seconds). Note that based on the discussion in the previous paragraph is unlikely that a remote with such a low Minimum Information Rate will remain in the network except when all of the following conditions are met:
• The remote is transmitting a BPSK or QPSK upstream carrier to an Evolution line card under clear sky conditions.
• The remote is a fixed-site (non-mobile) remote in a Ku Band, C Band or X Band network. Therefore, configuring a rate below the recommended setting may cause the remote to drop out of the network and be forced to reacquire if there is insufficient margin to handle rain
NOTE: When using the Idle and Dormant States feature in conjunction with Remote Sleep Mode, the Sleep timeout should be longer than the Idle and Dormant State timeouts. Otherwise, the remote will sleep before the Dormant State timeout expires and the Idle and State feature will be ineffective. See
Feature Description
fade or if 8PSK upstream modulation is chosen. Because of these constraints, do not configure a Minimum Information Rate for any state below the recommended settings unless the network configuration and system design permit a lower rate.
Note also that in DVB-S2 networks with Adaptive Coding and Modulation (ACM) enabled, if a remote enters a downstream “fast fade” condition the remote attempts to report its current SNR to the hub every second. This allows the hub to quickly adjust the outbound MODCOD of the remote to compensate for the fade. If the remote is in the Idle State or Dormant State, the remote may not have sufficient TDMA slots to allow it to increase its inbound transmission rate to report the fade. As a result, the hub may not adjust the remote’s MODCOD quickly enough to avoid the loss some downstream data by the remote.
Beginning with iDX Release 3.2, if the hub detects that a remote’s upstream C/N is dropping rapidly due to fade conditions, the Minimum Information Rate of the remote is automatically increased so that the power control algorithm can react quickly to adjust the remote’s transmit power. If the remote requires additional slots, the currently-configured Minimum Information Rate of the remote is ignored and the slot allocation rate is determined by the software. For more information on power control see UCP Power Control and Fade Detection