Client mobility allows the node to use host monitoring (SHCV, ANCP, split DHCP) to remove network and server state when a host is removed locally. This allows for MAC addressed learned and pinned to move based on policy parameters.
Subscriber Host Connectivity Verification (SHCV) configuration is mandatory. This allows clients to move from one SAP to another SAP in the same service. This is only applicable in a VPLS service and group interfaces.
The first DHCP message on the new SAP with same MAC address (and IP address for group-interfaces) triggers SHCV and is always discarded.
SHCV checks that the host is no longer present on the SAP where the lease is currently populated to prevent spoofing. When SHCV detects that the host is not present on the original SAP, the lease-state is removed. The next DHCP message on the new SAP can initiate the host.