Installation guide

57
Cisco uBR7200 Series Universal Broadband Router Wireless Modem Card and Subsystem Installation and Configuration
78-6030-03
Command Reference
radio arq (automatic repeat query)
Use these commands in interface configuration mode to configure the Automatic Repeat Query
mechanism on the wireless modem card. With ARQ, the transmitter resends data that is received in error
at the receiver. This allows the radio link to run at a substantially lower error rate in RF channels with
rapid fading or bursty interference.
Enabling requires a small amount of additional overhead and increases the latency of the link. However,
even with small maximum latency and maximum overhead settings, enabling ARQ can dramatically
improve link performance.
Latency values should be related to the bandwidth and throughput settings for channel-setup. Refer to
Table 12.
Note The by default latency value for arq on is 11 ms, which can be used for all combinations of
bandwidth and throughput.
Note When ARQ is off, the latency value will be 2 ms for each direction of the link.
Use the no form of the command to reset the current ARQ settings to the default values (ARQ on, 11-ms
latency).
Use the on/off option to turn on or off the ARQ feature on the link.
Use the reset option to reset the current ARQ values to consistent settings based on the
channel-parameter configuration.
Note If ARQ is turned off, it may be difficult to establish the radio link in adverse environments.
Note These parameters can only be changed when the radio link is down (shut), and will not take effect
until the next no shut command is entered.
radio arq {pctBw dataLatency [BurstSize]} | {on | off | reset}
no radio arq
Table 12 Minimum Latency Values for Bandwidth and Throughput (ARQ on)
(Bandwidth Percentage Set to 12.5%)
Bandwidth Throughput Minimum Latency
6 MHz Low 11 ms
6 MHz Medium 7 ms
6 MHz High 7 ms
12 MHz Low 7 ms
12 MHz Medium 6 ms
12 MHz High 5 ms