Administrator Guide

Layer 2 Switching Commands 364
User Guidelines
The DHCP binding database is persistently stored on a configured external
server or locally in flash, depending on the user configuration. A row-wise
checksum is placed in the text file that is stored on the configured TFTP
server. On switch startup, the switch reads the text file and uses the contents
to build the DHCP snooping database. If the calculated checksum value
equals the stored checksum, the switch uses the entries from the binding file
and populates the binding database. Checksum failure or a connection
problem to the external configured server causes the switch to lose the
bindings and may cause connectivity loss for hosts if IPSG or DAI is enabled.
ipv6 dhcp snooping database write-delay
Use the ipv6 dhcp snooping database write-delay command to configure the
time period between successive writes of the binding database. The binding
database is used to persistently store the DHCP bindings. Use the no form of
the command to return the write delay to the default value.
Syntax
ipv6 dhcp snooping database write-delay seconds
no ipv6 dhcp snooping write-delay
• seconds —The period of time between successive writes of the binding
database to persistent storage. (Range 15-86400 seconds.)
Default Configuration
By default, the write delay is 300 seconds.
Command Modes
Global Configuration mode
User Guidelines
The binding database is cached in memory and written to storage every write-
delay
seconds.
2CSNXXX_SWUM204.book Page 364 Monday, January 25, 2016 1:25 PM