IBM strives to lead in the creation, development and manufacture of the industry's most advanced information technologies, including computer systems, software, networking systems, storage devices and microelectronics. And the worldwide network of IBM solutions and services professionals translates these advanced technologies into business value for the company's customers.BladeCenter HT provides support for internal links between redundant pairs of switch modules. These inter-switch links (or ISLs) provide the ability to establish load balancing or high-speed communications between switch pairs without consuming valuable external ports. The internal links are provided via optional switch interposers, or extenders, which are installed behind the switch module and provide a connection link between the Gb Switch/Bridge Bays and the BladeCenter HT midplane which maintains the internal fabric and signaling between the two in the BladeCenter HT I/O module bay. Two of these interposer options must be ordered per switch pair, one for each of the switch and/or Pass Thru modules deployed with the BCHT chassis. Inter-switch links may not be applicable to all BladeCenter switch modules, please consult your WW product team for advice before ordering this option.