Re: Probing....

"Andrew Macpherson (Postmaster)" <"/I=A/S=Macpherson/OU=HAL0200/O=STC Technology Ltd/PRMD=STC Plc/"@gold-400.gb> Fri, 15 May 1992 15:25 UTC

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From: "Andrew Macpherson (Postmaster)" <"/I=A/S=Macpherson/OU=HAL0200/O=STC Technology Ltd/PRMD=STC Plc/"@gold-400.gb>
Message-ID: <1080.705941243@hedera2.bnr.co.uk>
To: directory-pilot@jnt.ac.uk, osi-ds@cs.ucl.ac.uk, panamas@paradise.ulcc.ac.uk, gb-dir-pilot@xtel.co.uk
Cc: osi-ds@ucl.ac.uk
Subject: Re: Probing....
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Alan Shepherd wrote:

| I'm not sure that this is the best way of looking at it.  It is true
| that to the outside world your data may be available, but to users at
| your site it isn't (and neither is data from anywhere else) unless they
| have sufficient knowledge to enable them to connect to other dsas.
| This will result in exasperation and an abandoning of the directory
| service by these users if the dsa is not available frequently or for
| long periods.
| 
| The other disadvantage is that some software (e.g. PP) is beginning to
| use the directory and is dependent, to some extent, on it being
| available.  It would seem to me therefore that the sooner you knew it
| wasn't and fixed it the better.
| 
| The best solution is for each site to have some probing mechanism to
| check their dsas (e.g. the new prodir suite), but in the absence of
| this, there is the possibility of some central site checking them
| all...

This is where we part company.  If the directory is important to you, you will
replicate it locally.  You will then user the capabilities of Steve's
string-encoding of PAs to address your multiple DSAs,  Thus transparently
providing replication for your users.

For instance my dsaptailor starts:

dsa_address Otter Internet=192.100.101.3+17003|Internet=192.100.101.2+17003

Which lists two seperate DSAs.

Secondly, there is now an snmp agent to monitor the DSAs.  It is much more
important that the monitoring is integrated with the monitoring of the
remainder of one's network, rather than with an out-of-band notification. 
The SNMP agent is the `probing' appropriate to the job.  which brings us back
to my earlier assertion that what we are interested in is information
availability.