Patent ID: 8275908

Claim:
Apparatus for implementing service requests from a common database in a multiple dynamic host configuration protocol (DHCP) server environment including multiple DHCP servers and multiple Internet small computer systems interface (ISCSI) adapters, said apparatus comprising: a plurality of said DHCP servers; each of a plurality of said ISCSI adapters being connected to respective one of said plurality of DHCP servers; said ISCSI adapters including a plurality of target host bus adapters (HBAs); a plurality of Initiator ISCSI host bus adapters (HBAs) coupled to multiple ISCSI target host bus adapters; a DHCP authorization cache for implementing synchronized access for said plurality of said DHCP servers to the common database; said DHCP authorization cache includes a plurality of elements, each element for storing a plurality of entries including a client identifier, an ISCSI DHCP router pointer, an ISCSI DHCP router pointer alternate, and a timestamp; and said DHCP authorization cache includes an entry pointer; a virtual DHCP server coupled to said plurality of said DHCP servers and said DHCP authorization cache; said virtual DHCP server querying said DHCP authorization cache using a particular client identifier as a key and passes in a ISCSI DHCP router pointer of the DHCP server for the query; and returning an authorization success to the DHCP server for the query to serve the particular client identifier for a first time period, and responsive to other DHCP servers querying said DHCP authorization cache with the particular client identifier after the first time period, requiring the DHCP server for the query to wait a second time period before returning said authorization success to serve the particular client identifier; said virtual DHCP server responsive to identifying a match of a client identifier entry with the particular client identifier used as the key, and not identifying a corresponding matching entry of said ISCSI DHCP router pointer with said ISCSI DHCP router pointer of the DHCP server for the query during said first time period, setting said ISCSI DHCP router pointer alternate with the value of said ISCSI DHCP router pointer, and returning an authorization failure to the DHCP server for the query.