User's Guide

Appendix C. DS.11 FAQ
User's Guide C-2 BreezeNET BU-DS.11/RB-DS.11
Why are there 11 channels and only 3 usable?
The IEEE802.11 specification calls out 11 selectable channels (USA) between 2414MHz and
2462MHz. Because of the transmission bandwidth of the DS modulation, only 3 channels are non-
overlapping. Those are channels 1, 6, and 11, therefore, only 3 systems may be co-located. The
other channels may be used, however, if used with another DS system co-located on another nearby
channel, the overlap will cause them to share the bandwidth yielding no increase in aggregate data
bandwidth. When operating in a single channel network, the other channels may be used to move
away from any in band interference that may exist.
What if the DS.11 link experiences interference?
If interference is affecting the DS.11 link, one of the other channels may be selected to operate
away from the frequency of the interference. Also, physically re-locating the antennas may help.
What is the typical latency of a BU-DS.11/RB-DS.11?
A point to point link would realize about 3mS latency.
Can the BU-DS.11/RB-DS.11 firmware be upgraded?
Yes, the firmware in the BU-DS.11/RB-DS.11 is stored in flash and is upgraded using the built in
TFTP server.
Can just anyone erase my BU-DS.11/RB-DS.11 flash or change the firmware?
No, the TFTP server in the BU-DS.11/RB-DS.11 requires the SNMP write community name
(password) to perform an upgrade.
Can I corrupt my firmware flash when upgrading to a new version?
If the TFTP file transfer is interrupted during a flash update it is possible to corrupt the firmware.
Fortunately, the DS.11 has a backup flash, which contains the previous version for firmware. If the
primary flash is corrupt, then the backup is automatically used to return the unit to an operating
state.
When does the back up flash image get upgraded?
After completing a firmware upgrade, the backup flash containing the old firmware version is
overwritten with the new version on the new power on cycle.