  Fibre Channel SAN: hubs vs switches? 
 The Question is:
 
Hello,
My name is Nir Levy, I live in Israel and I'm an OpenVMS system manager. I
 would like to ask you why does OpenVMS 7.2-1, and I heard the even future
 versions, do not supprot HUBS for implementing a fibre channel net? Only
 SWITCHES is currently supported.
 
Switches are very expensinve and I have many HUBS from my NT network why can't
 I use them ?
 
Thank You
 
 The Answer is:
 
  While it appeared possible to extend OpenVMS to provide a functioning,
  robust, multi-host Fibre Channel Arbitrated Loop (FC-AL) hub-based
  configuration, several issues around the technical feasibility arose
  given the (lack of) maturity of the FC hub components initially available.
  Accordingly, a decision was made to concentrate the OpenVMS Fibre Channel
  (FC) environment around a switch-based Fabric architecture.  This decision
  was made in conjunction with a similar decision made within the Compaq
  Tru64 UNIX engineering team.
 
  During the two years since that decision, there have been various
  improvements in FC-AL capabilities.  However, even with these changes,
  the limit of a two-host environment for shared storage still exists.
 
  For customers that currently require these smaller StorageWorks
  configurations, multi-host UltraSCSI (and HSZ-series controllers,
  as required) appear to be the StorageWorks technology that will be
  more desirable (and more economical) for (most) smaller OpenVMS
  cluster configurations -- and the same StorageWorks components used
  for the UltraSCSI storage can typically be (re)used, should future
  migration to FC StorageWorks solutions become interesting.
 
  The OpenVMS Wizard expects OpenVMS Engineering will continue to
  revisit the feasibility of the extension of support to smaller FC-AL
  configurations, particularly as the maturity of the FC-AL and Hub
  technology continues and as the expected improvements within
  FC-based storage occur.
 
