Subscriber Services: DHCP and DHCPv6 asymmetric lease

You can configure a shorter lease for DHCP and DHCPv6 that overrides the original lease configuration. The shorter lease is also known as an asymmetric lease. When the client successfully requests a lease extension, the client renews the short lease for the same duration. The short lease continues until the original or long lease offered by DHCP or DHCPv6 expires. The short lease provides a means to force a lease renewal for particular hosts or clients before the original lease expires and a form of liveness detection. When the client is no longer using the lease, the client stops requesting a lease renewal; this is reported to the DHCP server or DHCP relay agent as an expiration of the short lease. In the absence of a short lease, client inactivity can be detected only when the long lease expires. The short lease enables earlier detection and frees up address resources earlier than is possible with the long lease.

Configure the short lease duration for DHCP or DHCPv6 globally or by group with the following statement at any [edit...(dhcp-local-server | dhcp-relay)...overrides] hierarchy level:

• asymmetric-lease-time seconds, where seconds is in the range 600 through 86,400 Configure the short lease duration for DHCPv6 delegated prefix addresses globally or by group with the following statement at any [edit...(dhcp-local-server | dhcp-relay)...overrides] hierarchy level:
• asymmetric-prefix-lease-time seconds, where seconds is in the range 600 through 86,400