Issue 2753: Availability status under wrap condition                                                                                                                                                                (log_service-ftf)
Source: Fujitsu (Mr. Tom Rutt, tom@coastin.com)
Nature: Uncategorized Issue
Severity: 
Summary: The AB raised an issue regarding an ambiguity on the proper value 
for the availability status, when the log is in the wrap condition. 
The FTF editor  added the following sentence at the top of page 2-12 
of to telecom/99-05-01, in an effort to clarify the AB issue: 

"When a log is full its availability status will change to 
indicate the log full condition. If a log's full action is set to 
'wrap', it will never be in 'full' condition." 

This same ambiguity was discussed the ITU-T group which 
originally wrote the X.735 spec, and their proposed resolution 
has the opposite affect: 

Add the following explanation to the availability status value as a 
separate para after the text discussing wrap event behaviour : 

"The availability status indicates "logfull" when the capacity of 
the log is exceeded. In the case where halt behaviour is 
specified for the log the value implies no more records can be 
added.   If wrap behaviour is specified, the value continues to 
remain as log full even though forthcoming records will be added 
by overwriting existing records. The wrap mode combined with 
logfull condition indicates that old records are lost as 
overwriting takes place. If records are deleted from the log, the 
logfull status value is removed from the availability status in 
either halt or wrap mode." 

The reason the ITU group has recommended "full" status is that it 
gives the information that records are being overwritten. When 
the log is full, records will be lost in response to forthcoming 
events.  In Halt mode new records are not logged (i.e., lost), 
while in the wrap mode the oldest records are overwritten (i.e., 
lost).  If a client comes and deletes records, then 
availabilitystatus can be reset. Otherwise one needs to have a 
different behaviour for halt and wrap in terms of the value for 
availability status. 

Resolution: Accept the ITU-T proposal, when in wrap mode, the log is considered to be full.
Revised Text: Specification Text 
Section 3.2.4.5: Log Full Action 
When a log is full its availablity status will change to indicate the log full condition. 
If the log's full action is set to "halt", then no new log records will be added and the 
event will be lost. When log records are deleted the log will leave the log full condition 
and new log records can be added to the log. If the log's full action is set to "wrap", 
then new records will be added overwritting the oldest records contained in the log. 
When log records are deleted the log will leave the log full condition and new log records 
will no longer overwrite existing log records in the log. 

Specification IDL 
No Change 

Actions taken: 
Completed.
Actions taken:
June 17, 1999: received issue
July 27, 1999: closed issue
Discussion: 

End of Annotations:=====