User's Manual

Deployment

Trango Broadband Wireless — User Manual M2400S Rev A

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[AP Total nRx] 1000 pkts

[AP Total nRxErr] 0 pkts

[SU Total nTx] 1000 pkts

[SU Total nRx] 1000 pkts

[SU Total nRxErr] 0 pkts

[AP to SU Error Rate] 0.00 %

[SU to AP Error Rate] 0.00 %

[Avg of Throughput] 5120 kbps

#> Success.

su testrflink <su#>

This command also checks the integrity of the wireless link from the standpoint of over-the-air packet loss. In

this test, the AP will send 20 large (1512 byte) packets to the SU and the SU will in turn send the same 20

packets back to the AP. The expected result of an error free link is 20..20..20, indicating (in the following

sequence) 20 packets sent from AP, 20 packets received back at AP, 20 packets received at the SU. Any

results other than 20..20..20 indicate a performance problem, most likely due to interference or inadequate

signal to noise ratio. For thorough results it is recommended you run the command repeatedly for at least 1

minute or more to determine if packets are passing without error consistently over time. This command will

give results without the help from ARQ. Note: This test does not provide as much detail as linktest

The “r” is used in this command to repeat the rf link test repeatedly until the user terminates the test by hitting

SPACE ENTER.

Example:

#> su testrflink 1 r

Press [space] then [enter] to stop

[len] 1512

[suid] 1

[ 0] ...........[AP Tx] 20 [AP Rx] 20 [SU Rx] 20

[ 1] ...........[AP Tx] 20 [AP Rx] 20 [SU Rx] 20

[ 2] ...........[AP Tx] 20 [AP Rx] 20 [SU Rx] 20

[ 3] ...........[AP Tx] 20 [AP Rx] 20 [SU Rx] 20

[ 4] ...........[AP Tx] 20 [AP Rx] 20 [SU Rx] 20

[ 5] ...........[AP Tx] 20 [AP Rx] 20 [SU Rx] 20

Success.

As another example, a result of 20..10..18 would indicate 20 packets sent from the AP, 18 packets received at

the SU, 10 packets received back to the AP. These types of results may be caused by Fresnel zone

infringements, interference or multi-path.

ARQ with Selected Repeat and Multirate Feature

The M900S features ARQ or “Automatic Request for Re-transmission” which provides the ability to correct for

missing or erred packets of data by asking the sender to re-transmit the data.

Both the AP and SU units implement a form of ARQ known as Selective Repeat.

The units make a first attempt at transmitting a data frame using the 5.5 Mbps rate. Then, if a re-try is

required, that 2nd attempt shall be at 5.5 Mbps rate as well. e 3rd and 4th attempts will be at a rate of 2.75

Mbps. After the 4th attempt there will be no more re-tries. A counter describing “maximum retries reached”

will be incremented.

• A minimum of 100ms is placed between re-transmission requests.