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Bad Response to Establish Pathing Control Frame in Peer-to-Peer Remote Copy Function

IP.com Disclosure Number: IPCOM000117123D
Original Publication Date: 1995-Dec-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 4 page(s) / 100K

Publishing Venue

IBM

Related People

Hathorn, RG: AUTHOR [+2]

Abstract

One of the primary functions in Peer-to-Peer remote copy is to establish CDC paths. ESCON architecture provides a frame, Establish Pathing Control (EPC), to accomplish this function.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 54% of the total text.

Bad Response to Establish Pathing Control Frame in Peer-to-Peer Remote
Copy Function

      One of the primary functions in Peer-to-Peer remote copy is to
establish CDC paths.  ESCON architecture provides a frame, Establish
Pathing Control (EPC), to accomplish this function.

      A method for handling bad response to EPC frame is disclosed.
The control unit receiving a bad response to the EPC frame goes
through a recovery procedure.  This also discloses how primary
control unit handles premature notification of peer to peer remote
copy path status to operator.

      Table 1 shows device level, Establish Pathing
Control-Acknowledgement, protocol between the primary control unit
and remote control unit.  This is a good case (good response to EPC
frame) scenario.  Note: CSOF implies connect start of frame and DEOF
implies disconnect end of frame.

      The logical path table in the primary control unit and the
remote control unit has an entry for Peer-to-Peer Remote Copy path at
the end of this protocol.  Primary control unit also maintains a
table of CDC path entries with the status (path established or not).
This status is also reported to operator.

      One or more of following situations can occur when bad response
or no response is received to EPC frame.
  o  EPC frames passing
  o  Logical Path table mismatch
  o  Extra EPC frame dispatched from secondary

      Table 2 describes the case where primary control unit receives
a bad r...