Viper User
Manual (001-5008-000 Rev6)
Page
92
1.1.57
Manual-SCAN
Manual-Scan is the default mode of operation. The Viper starts in the “Ready” state. In the
“Ready” state, the unit is quiet (no neighbor discovery control messages are sent). If the
user presses the “Force Scan” button, the unit goes into the “Scanning for Neighbors” state.
If other units are in the "Scanning for Neighbors" state, the unit will automatically be
triggered to go into the "Scanning for Neighbors" state.
In the "Scanning for Neighbors" state, the Viper is learning about other units and the other
units are learning about this unit. The unit goes from the "Scanning for Neighbors" state to
the "Saving Neighbor Table" state when it doesn’t learn anything new for a given amount of
time.
In the "Saving Neighbor Table" state, the content of the neighbor table is saved in nvram
(nonvolatile ram). If the unit reboots, the content of the neighbor table is restored from the
nvram.
The unit goes from the "Saving Neighbor Table" state to the "Ready" state.
1.1.58
Auto-SCAN
In the Auto-Scan mode, Viper begins "Scanning for Neighbors". In the "Scanning for
Neighbors" state, Viper discovers other Viper units in the network and other Viper units
learn about the Viper initiating the scan.
Viper goes from "Scanning for Neighbors" state to "Ready" state when it doesn’t discover
another Viper for a given amount of time.
In "Ready" state, Viper will generate a “keep alive” packet periodically. In "Ready" state,
Viper performs broken link detection. Viper is monitoring the “keep alive” packets of other
Vipers (1 hop away). Viper knows the interval period for other Vipers generating their
“keep alive” packets. If Viper (A) fails to receive four “keep alive” packets in a row from
Viper (B), Viper (A) removes Viper (B) from its neighbor table and goes into the "Scanning
for Neighbors" state.
If a user presses the “Force Scan” button, Viper goes into the "Scanning for Neighbors"
state. If other Vipers are in the "Scanning for Neighbors" state, Viper will automatically go
into "Scanning for Neighbors" state.
Note: Care should be taken when selecting Auto-Scan mode for the permanent operating
mode of a Viper network. Auto-Scan mode could generate a large number of neighbor
discovery control messages in a large Viper network
1.1.59
Disabled
In the disabled state, Viper does not send neighbor discovery packets, nor does it process
neighbor discovery packets generated by other Vipers. The user can enter static entries in
the Neighbor Table.
LOCAL STATUS
Local Status displays operating state information about the local discovery module. The
device shown in Figure 11.2 is currently Scanning for Neighbors. See below for additional
Discovery States.
