Configuration
Tsunami MP.11 5012/5054-SUI Installation and Management
Network Parameters
65
NOTE:
To enable roaming, you must enable
Roaming Status
on both the BSU and the SU.
An SU scans all available channels for a given bandwidth during roaming. In order to reduce the number of channels an
SU has to scan and thus decrease the roaming time, a channel priority list that tells the SU what channels to scan is
implemented. Each channel in the channel priority list is specified with its corresponding bandwidth and the priority with
which it should be scanned, either “Active” (standard priority), “Active High” (high priority), or “Inactive”.
An SU will scan all channels indicated as “Active” during roaming. However, it will scan active channels indicated as
“High Priority” before scanning active channels indicated as standard priority. Channels that are not going to be used in
the wireless network should be configured as “Inactive” so that the SU can skip over those channels during scanning
saving this way time.
A BSU broadcasts the channel priority list to all valid authenticated SUs in its sector. It re-broadcasts the channel priority
list to all SUs every time the list is updated on the BSU. For information for configuring the channel priority list on the BSU
see the
Tsunami MP.11-R Installation and Management Guide.
Note that an SU may roam from one BSU with a bandwidth setting to another BSU with a different bandwidth setting.
Since in this case more channels need to be scanned than with only one channel bandwidth setting, it is important that
the channel priority list mentioned above is properly used to limit scanning time.
When
Scanning Across Bandwidth
), the SU supports bandwidth
selection of the communications channel of either 20 MHz, 10 MHz, or 5 MHz, as available. This allows the BSUs in the
network to be set to different bandwidths while an SU can still roam from one BSU to the next, because it will not only
scan other frequencies (when the signal level or quality are lower than the threshold) but it will also switch to other
bandwidths to find a BSU that may be on another bandwidth than its current one.
During roaming, the SU will start scanning first the channels on its current bandwidth from the “Active” channel list
provided by the BSU in order to find a BSU to register, since that is the most likely setting for other BSUs in the network.
If the SU cannot find an acceptable roaming candidate, it will switch bandwidth and start scanning channels on that
corresponding bandwidth from the “Active” channel list provided by the BSU. The process is repeated until the SU finds
an appropriate BSU to register.
In the example above, an SU whose current bandwidth is 20 MHz will start scanning all active channels within the
bandwidth of 20 MHz. If it cannot find a suitable BSU, it will switch to a 10 MHz bandwidth and start scanning all active
channels within that bandwidth, in this case channel 56 first since it is configured as high priority and channel 60 next. No
channels will be scanned on the 5 MHz bandwidth since all those channels are configured as inactive.
DHCP Server
When enabled, the DHCP server allows allocation of IP addresses to hosts on the Ethernet side of the SU or BSU.
Specifically, the DHCP Server feature lets the SU or BSU respond to DHCP requests from Ethernet hosts with the
following information:
• Host IP address
• Gateway IP address
• Subnet Mask
• DNS Primary Server IP address
• DNS Secondary Server IP
Click
Configure
>
Network
>
DHCP Server
to enable the unit on a DHCP Server.
