US 6,983,330 B1
Method and apparatus for using multiple paths for processing out of band commands
Fred Oliveira, Sudbury, Mass. (US); Matthew J. D'Errico, Southborough, Mass. (US); and Kevin Rodgers, Derry, N.H. (US)
Assigned to EMC Corporation, Hopkinton, Mass. (US)
Filed on Dec. 29, 1999, as Appl. No. 9/474,607.
Int. Cl. G06F 15/16 (2006.01); G06F 15/173 (2006.01); G06F 11/00 (2006.01); G06F 9/44 (2006.01); H03K 17/00 (2006.01); H04Q 11/00 (2006.01)
U.S. Cl. 709—239 22 Claims
OG exemplary drawing
 
15. A host computer for use in a multi-path system including the host computer, a device and multiple physical paths coupling the host computer to the device, the host computer comprising:
at least one processor to execute an out of band control command identifying a target address in the device and bypassing at least one layer in a normal read/write path in the host computer, the out of band control command further identifying, from among the multiple physical paths, a target physical path for transmission of the out of band control command between the host computer and the device;
a plurality of adapters each adapted to interface the host computer to one of the multiple physical paths; and
at least one controller that:
selects a selected physical path for transmitting the out of band control command between the host computer and the device, the selected physical path being selected form among the multiple physical paths based upon a selection criteria that enables the selected physical path to be other than the target physical path identified by the out of band control command; and
transmits the out of band control through the one of the plurality of adapters corresponding to the selected path to the device over the selected physical path.