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RETENTION OF LOGICAL PATHS DURING TRANSIENT FC-PH LINK FAILURES

IP.com Disclosure Number: IPCOM000013031D
Original Publication Date: 2002-Mar-21
Included in the Prior Art Database: 2003-Jun-12

Publishing Venue

IBM

Abstract

A procedure is described which allows a fibrechannel N_Port to retain FC-SB-2 upper level protocol information relating to logical paths after transient link failures. Transient link failures are relatively short link failures which are due to to transient events such as noise bursts or loose cables. Distinguishing transient link failures from non-transient link failures has several advantages. First, it allows FC-SB-2 operations to continue normally after transient link failures, and it allows resources to be released after non-transient link failures. Retaining FC-SB-2 logical paths during transient link failures also prevents these link failures from causing errors at the System Control Program, and thereby causing the possible loss of reserves at the device and loss of access to the device. After a non-transient link failure, there is a high probability that the logical paths to a control unit are no longer usable. In this case, a control unit may immediately release resources associated with FC-SB-2 logical paths. There are two phases in the procedure: a) transient link failure detection, b) transient link failure recovery. Transient Link Failure Detection