The DHCP client normally maintains the IP lease in compliance with the RFCs. Sometimes the server will not renew the lease. Non-renewal is usually part of network service operations. The loss of the IP lease requires connections using that IP address to cease.
Figure F.1-6 Maintain Lease
Actor: DHCP client
Role: Deals with lease renewal and expiration.
Actor: DHCP Server
Role: Renewing or deliberately letting leases expire (sometimes done as part of network service operations).
RFC-2131 DHCP Protocol
RFC-2132 DHCP Options
The DHCP client shall maintain a lease on the IP address in accordance with the DHCP protocol as specified in RFC-2131 and RFC-2132. There is a possibility that the DHCP Server may fail, or may choose not to renew the lease.
In the event that the DHCP lease expires without being renewed, any still active DICOM connections may be aborted (AP-Abort).
Note: There is usually a period (typically between several minutes and several days) between the request for lease extension and actual expiration of the lease. The application might take advantage of this to perform a graceful association release rather than the abrupt shutdown of an AP-Abort.