(Originally published by Deepesh Panicker)
Introduction
The Frame Utilization Statistics is a feature introduced first in the 13.4 software release which helps the user understand how effectively the RF channel is being utilized. Customers have indicated a desire for some form of frame utilization diagnostics which can be used to identify if their Time Division Duplex (TDD) frame utilization is excessive, and if so, what can be done to improve the situation. This forms the first step of identifying the TDD frame utilization information. If the customer finds excessive utilization based on this stats, the second step would be to take several actions, such as further sectorization or fine tuning the uplink/downlink ratio. Efficient use of the TDD frame will help optimize customer experience.
Feature Description
A TDD frame is nothing but a grouping of slots in both the downlink and uplink directions. A TDD frame is broken into 1) Unscheduled downlink slots (preambles, beacons, scheduling map and BER); 2) Scheduled downlink acknowledgement slots; 3) Scheduled downlink user data slots; 4) Scheduled uplink acknowledgement slots; 5) Scheduled uplink user data slots; 6) Unscheduled uplink slots (bandwidth requests and registration requests). Note that this can be generalized into Downlink (Unscheduled/Scheduled) slots and Uplink (Unscheduled/Scheduled) slots.
The frame utilization statistics feature monitors only the “scheduled” portion of the TDD frame. Frame utilization does NOT refer to “unscheduled” slots (preambles, beacons, scheduling maps, BER, bandwidth requests and registration requests).The Frame utilization statistics can be reported using 3 different intervals: every 1, 5 or 15 minutes.
In each level the following information are available:
- Downlink statistics
These are the statistics specific to the downlink section of a TDD frame. The following information is available to the user. - Percentage total
This is the percentage of downlink data slots used against the maximum number of slots possible in the given level of interval. - Total downlink slots
This is the sum of all downlink data slots used in the given level of interval. - Max downlink slots
This is the maximum possible downlink data slots. This is based on the configuration of Channel Bandwidth, Frame period, uplink/downlink allocation, contention slots and the level of interval. - Registration and Control message slots
The number of downlink data slots used for registration and other control messages. - High priority data slots
The number of downlink data slots used for high priority downlink traffic. - Low priority data slots
The number of downlink data slots used for low priority downlink traffic. - Broadcast or multicast data slots
The number of downlink data slots used for broadcast and multicast traffic. - Canopy MAC Acknowledgements
The number of downlink data slots used as ACKs. - Uplink Statistics
These are the statistics specific to the uplink section of a TDD frame. The following information is available to the user. - Percentage total
This is the percentage of uplink data slots used against the maximum number of uplink slots possible in the given level of interval. - Total uplink slots
This is the sum of all uplink data slots used in the given level of interval. - Max uplink slots
This is the maximum possible uplink data slots. This is based on the configuration of Channel Bandwidth, Frame period, uplink/downlink allocation, contention slots and the level of interval. - High priority data slots
The number of downlink data slots used for high priority uplink traffic. - Low priority data slots
The number of downlink data slots used for low priority uplink traffic. - Canopy MAC Acknowledgements
The number of uplink data slots used as ACKs. - Discard Statistics
Excessive frame utilization would cause discard of packets either at the Ethernet side or at the RF side. The discard statistics shown will be the number of packets discarded in the last interval. Increase in discard counts indicate some action needs to be taken to reduce that for better performance. The following information is available. - Ethernet discards
This indicates the number of Ethernet packets discarded in the IN queue and OUT queue. - RF discards
This indicates the number of packets discarded over radio in the IN queue and OUT queue.
User Experience
User can obtain the frame utilization statistics either through SNMP OIDs or the Web UI. The SNMP OIDs are placed under the OID group WHISP-APS-MIB:whispApsFrUtlStats (.1.3.6.1.4.1.161.19.3.1.12). The statistics for low level interval of 30 seconds are under the OID group WHISP-APS-MIB: whispApsFrUtlStatsIntervalLow (.1.3.6.1.4.1.161.19.3.1.12.1). The statistics for the mid-level interval of 3 minutes are under the OID group WHISP-APS-MIB: whispApsFrUtlStatsIntervalMedium (.1.3.6.1.4.1.161.19.3.1.12.2). And the statistics for the high level interval of 15 minutes are under the OID group WHISP-APS-MIB: whispApsFrUtlStatsIntervalHigh (.1.3.6.1.4.1.161.19.3.1.12.3).
The Figures below show the SNMP tree and the Web UI.
Figure 1 : SNMP Tree for Frame Utilization statistics
Figure 2 : Web UI for Frame Utilization statistics
Platforms Supported
The feature is supported on the PMP 450 Platform, including PMP and PTP 450 and 450i radios. (Note that the backhauls will have only the downlink scheduler based statistics.)