Date: Wed, 11 Jun 2003 14:41:07 +0400 From: Evgeny Dolgopiat <dolgop@mccinet.ru> To: freebsd-net@freebsd.org Cc: Archie Cobbs <archie@FreeBSD.org> Subject: Link failure detection algorithm for one2many netgraph node. Message-ID: <200306111441.07234.dolgop@mccinet.ru>
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Hello, All!
I have developed a simple link failure detection algorithm for one2many
netgraph node. I called it "heartbeat algorithm" :)
This is brief description:
What is it
Link failure determination for one2many netgraph node.
How it works
It is implemented as "heartbeat" packet counters on all one2many tranked
interfaces. If the number of
packest hook received is less for some specified value than max number of
packest, received by another hooks
of the node, then interface is marked as failed (subnet or link failure). If
this difference is less than this value and
interface is marked as failed, then interface is up and working.
How to setup
Algorithm number is 2, so to configure node one should issue "setconfig
{xmitAlg=1 failAlg=2}" message.
There are two params of algorithm:
timeout - time between sending of hearbeat packets (integer number of 1/10
sec)
period - number of timeouts for failure determination statistics
Default values are timeout=10 and period=10.
Two new node messages: "gethbconfig" and "sethbconfig {timeout=X period=Y}"
for getting and setting
heartbeat algorithm params.
Tech data
"Heartbeat" packet uses ethernet broadcast address (ff:ff:ff:ff:ff:ff) and
packet type set to
NG_ONE2MANY_HEARTBEAT_PROTO in the ethernet header. Expected timings are:
failure determination:
average - 1.5*timeout*period
worst - 2*timeout*period
up determination:
average - 0.5*timeout*period
worst - timeout*period
Author: Evgeny Dolgopiat <dolgop@mccinet.ru>
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