  OpenVMS Cluster spanning one mile? (or more) 
 The Question is:
 
At the present time we have a DEC Alpha 8400 clustered via a star coupler to
a storage works cabinet in the hospital data center.
 
The question is:  Is it possible to cluster two Dec Alpha 8400's if they are
a mile away from each other.  This second 8400 would be a failover for the
primary 8400.  They would both be on a 100 mb switch servicing the
University of New Mexico Hospital an
d campus.
 
If possible I would like to get a drawing or something that shows it.  Thank
You
 
 
 The Answer is:
 
  Please contact the Compaq Customer Support Center for technical
  assistance.
 
  Please see the Guidelines for OpenVMS Cluster Configurations manual,
  part of the OpenVMS documentation set, for detailed information on
  the available configurations.
 
  This would be a multiple-interconnect configuration, with CI used
  for the local communications and a point-to-point network link (and
  the appropriate bridge, brouter, repeater, or switch) used to connect
  the LAN segments at the two sites.
 
  OpenVMS Clusters spanning 150 miles are supported using standard
  products.  Larger spans can (potentially) be supported, as part of
  the disaster-tolerant cluster configuration services.
 
  From the OpenVMS Cluster Software Product Description (SPD):
 
	...
 
o  OpenVMS Cluster CPUs that are configured using WAN interconnects
   must adhere to the detailed line specifications described in the
   Guidelines for OpenVMS Cluster Configurations manual. The maximum
   CPU separation is 150 miles.
 
	...
 
o  LAN segments can be bridged to form an extended LAN (ELAN). The ELAN
   must conform to IEEE 802.1D, with the following restrictions:
 
   -  All LAN paths used for OpenVMS Cluster communication must
      operate with a nominal bandwidth of at least 10 megabits per
      second.
 
   -  The ELAN must be capable of delivering packets that use the padded
      Ethernet Version 2.0 packet format and the FDDI SNAP/SAP packet
      format.
 
   -  The ELAN must be able to deliver packets with a maximum data field
      length of at least 1080 bytes.[1]
 
   -  The maximum number of bridges between any two end nodes is seven.
 
   -  The maximum transit delay through any bridge must not exceed two
      seconds.
 
   -  The ELAN must provide error-detection capability between end nodes
      that is equivalent to that provided by the Ethernet and FDDI data
      link frame-check sequences.
 
