
Ping Polling Introduction
©2008 Allied Telesis Inc. All rights reserved.
Software Version 5.2.1
AlliedWare Plus
TM
Operating System Software Reference C613-50003-00 REV E
62.3
Figure 62-1: Interaction between states and parameters for ping polling
On some operating systems, some servers may respond to a ping even if no other functionality
is available, and therefore remain in an Up state while malfunctioning.
Responding to
status changes
To configuring your device to determine and respond to changes in a device’s reachability, you
will need to:
■
create a polling instance to periodically ping the device
■
create scripts to run when the device becomes unreachable and when it becomes
reachable again
■
configure triggers to run these scripts
To set a trigger to activate when a device’s status changes, its trigger type must be
ping-poll
.
This is with the following command in the trigger’s configuration mode:
awplus(config-trigger)#
type ping-poll <1-100> {up|down}
where
up
activates the trigger when the device is reachable, and
down
activates the trigger
when the device is unreachable.
If you use triggers to open a backup link to a remote device in the event of the primary link
failing (rather than the remote device failing), the backup link and primary link must point to
different IP addresses on the remote device. Otherwise, when the backup link points to the IP
address that your device is polling, your device receives ping replies through the backup link,
considers the device to be reachable again, and attempts to reopen the primary link instead of
using the backup link.
See
Chapter 59, Triggers Introduction
for more information about configuring Triggers with
Ping Polling.
ping_02
Time
00:00:33
00:01:03
00:01:33
00:02:03
00:02:33
00:02:34
00:02:35
00:02:36
00:01:35
00:01:36
.
.
00:02:48
00:02:49
00:02:50
00:03:20
00:03:50
success
success
success
success
fail
success
fail
fail
fail
fail
.
.
success
success
success
success
success
Ping polling returns
to normal-interval rate
}
The device fails to
respond to 3 out of
4 polls (fail-count=3,
sample-size=4)
------ device determined unreachable ------
Polling continues at the
critical-interval rate
Polling Result
------ device determined reachable ------
}
The device responds to
3 consequtive pings
(up-count=3)
When polling first starts
it assumes the device is
down and uses the
critical-interval rate
00:00:01
00:00:02
00:00:03
success
success
success
}
Polling waits for the
device to respond to
3 consequtive pings
(up-count=3)
------ device determined reachable ------
Ping polling begins
polling at the
normal-interval rate
Begins polling at the
critical-interval rate
.
.