Upgrade And Downgrade Considerations; Configuring Dhcpv6 Relay Agent Prefix Delegation Notification - Brocade Communications Systems FastIron SX 800 Configuration Manual

NTP synchronization is needed for the correct updation of prefix age. If the NTP is not configured, then the DHCP prefix
delegation will still read the flash, but the prefix age may not be correct.

Upgrade and downgrade considerations

• When a router is upgraded to the version of software that supports this feature, the saved information about delegated prefixes
will be examined and if the delegated prefix lifetime is not expired, then the prefix will be added to the IPv6 static route table.
• When a router is downgraded to the version of software that does not support this feature, the saved information about
delegated prefixes is retained and it cannot be used.

Configuring DHCPv6 Relay Agent Prefix Delegation Notification

To set the number of delegated prefixes that can be learned at the global system level, use the ipv6 dhcp-relay maximum-delegated-
prefixes command.
By default, the DHCPv6 Relay Agent Prefix Delegation Notification is enabled when the DHCPv6 relay agent feature is enabled on an
interface. User can disable the DHCPv6 Relay Agent Prefix Delegation Notification at the system or the interface level by setting ipv6
dhcp-relay maximum-delegated-prefixes to 0 at the system or interface level as required.
NOTE
Make sure that there is enough free space in the flash memory to save information about delegated prefixes in flash on both the
Active and Standby management processor
device(config)# ipv6 dhcp-relay maximum-delegated-prefixes 500
The value parameter is used to limit the maximum number of prefixes that can be learned at the global level. The range is from 0 to 512.
The default value is 500.
Syntax: [no] ipv6 dhcp-relay maximum-delegated-prefixes value
The value parameter is used to limit the maximum number of prefixes that can be learned at the global level. The range is from 0 to 512.
The default value is 500.
Use the no ipv6 dhcp-relay maximum-delegated-prefixes command to set the parameter to the default value of the specified platform.
Refer to Enabling DHCPv6 Relay Agent Prefix Delegation notification on an interface
NOTE
The DHCPv6 prefix delegation default for ICX 7750 is
50.
Enabling DHCPv6 Relay Agent Prefix Delegation notification on an interface
To set the number of delegated prefixes that can be learned at the interface level, use the ipv6 dhcp-relay maximum-delegated-prefixes
command. This command limits the maximum number of prefixes that can be learned on the interface.
device(config-if-eth 1/2/1)# ipv6 dhcp-relay maximum-delegated-prefixes 100
Syntax: [no] ipv6 dhcp-relay maximum-delegated-prefixes value
The value parameter is used to limit the maximum number of prefixes that can be delegated. The range is from 0 to 512. The default
value is 100. The sum of all the delegated prefixes that can be learned at the interface level is limited by the system max.
Use the no ipv6 dhcp-relay maximum-delegated-prefixes command to set the parameter to the default value of the specified platform.
FastIron Ethernet Switch Layer 3 Routing
53-1003627-04
DHCPv6 Relay Agent Prefix Delegation Notification
on page 195 for more information.
195