Airtime reflects the amount of channel resources consumed by transmitting the frame over a particular link. This measure is approximate and designed for ease of implementation and interoperability. The airtime for each link is calculated as follows: where and are constants listed in Table 14-4 (Airtime cost constants) O Bt input parameter is the data rate (in Mb/s) r input parameter is the frame error rate for the test frame size ef Bt The airtime link metric shall be encoded as an unsigned integer in units of 0.01 TU. Airtime cost constants Parameter Recommended value Description Varies depending on Channel access overhead, which includes frame headers, O PHY training sequences, access protocol frames, etc. 8192 Number of bits in test Bt Table 14-5 (Parameters of the airtime link metric for extensible path selection framework) gives the parameters of the airtime link metric for the extensible path selection framework. Parameters of the airtime link metric for extensible path selection framework Parameter Notes Path Selection Metric ID See Table 9-218 (Active Path Selection Metric Identifier field values) in 9.4.2.98.3 (Active Path Selection Metric Identifier) Data type Unsigned integer, 0 < 4 294 967 296 metric Length of metric field 4 octets Operator for metric addition (+) aggregation
Airtime reflects the amount of channel resources consumed by transmitting the frame over a particular link. This measure is approximate and designed for ease of implementation and interoperability. The airtime for each link is calculated as follows: where O and Bt are constants listed in Table 14-4 (Airtime cost constants) input parameter r is the data rate (in Mb/s) input parameter ef is the frame error rate for the test frame size Bt The airtime link metric shall be encoded as an unsigned integer in units of 0.01 TU. Airtime cost constants Parameter Recommended value Description O Varies depending on PHY Channel access overhead, which includes frame headers, training sequences, access protocol frames, etc. Bt 8192 Number of bits in test Table 14-5 (Parameters of the airtime link metric for extensible path selection framework) gives the parameters of the airtime link metric for the extensible path selection framework. Parameters of the airtime link metric for extensible path selection framework Parameter Notes Path Selection Metric ID See Table 9-218 (Active Path Selection Metric Identifier field values) in 9.4.2.98.3 (Active Path Selection Metric Identifier) Data type Unsigned integer, 0 metric < 4 294 967 296 Length of metric field 4 octets Operator for metric aggregation addition (+)
11-17-1448-01-000m-mesh-high-phy-rate-airtime-link-metric.docx