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RE: Heartbeat Interval Format


  • Subject: RE: Heartbeat Interval Format
  • From: Ian Lowe
  • Date: Sun, 21 Mar 2004 10:49:00 +0000

Yeah, it is - and that's proven to be a nice network friendly level.

What I think frank is getting at is that this:

Parsing an xpl message on a small chip, If you jump to byte 5, that
single character (S, T or C) tells you the message class - byte 25 is
always the start of the message source.. and so on.

There are a whole bunch of fast navigation shortcuts in the message to
save parsing the whole thing - when you have figured out it's a
heartbeat, and you read a "{" after byte 10 that's the start of
the
message body, and you can jump ahead a known number of bytes to get the
interval and so on.

People can change the interval via xplhal manager - if they set it to a
single digit value, then the positions of the heartbeat tags within the
message are fixed to a greater extent.. if the number the user enters is
double digit, then that's harder to parse.

I think what I'm suggesting here is to place bounds on the value that
the user can specify for "interval=". The default is 5 minutes at
present, and that's working well. I'd suggest a minimum of 2 and a
maximum of 9 - especially as the expiration in xplhal is based on the
heartbeat interval - making it higher than 9 would have dead devices
(that hadn't hbeat.end'ed) hanging around for ages.

Ian.

-----Original Message-----
From: Tony Tofts [mailto:<a
href="/group/ukha_xpl/post?postID=5ZvGcI4reV3JP2YCf6JiGrWfHru8PElXMyc_4fAvEigly_kwaSCqnWbkJtRX3Pj9ggy-wfY">tony@x...</a>]
Sent: 21 March 2004 10:32
To: <a
href="/group/ukha_xpl/post?postID=3X-inSXr4XS5bVS3llZwSoqUej3hruu5FlhsnOpQWErRxZOPN0fWprtC7t9Cgcik2EMus0yCq_De105gTjd4sKg">ukha_xpl@xxxxxxx</a>
Subject: RE: [ukha_xpl] Heartbeat Interval Format

> In my opinion, a better solution is to set the maximum
> interval for the device at 9 minutes.

Isn't the default still 5 minutes?

And a device is considered dead if doesn't beat after 2 * interval + 1
minutes?

Thanks
Tony



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