Netgear FVX538v1 FVX538 Reference Manual - Page 211

Auto Rollover, con d WAN Failure Detection method.

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ProSafe VPN Firewall 200 FVX538 Reference Manual Auto Rollover When the WAN mode is configured for Auto Rollover, the primary link is active and secondary acts only as a backup. When the primary link goes down, the secondary link becomes active only until the primary link comes back up. The device monitors the status of the primary link using the configured WAN Failure Detection method. This section describes the logs generated when the WAN mode is set to Auto Rollover. System Logs: WAN Status, Auto Rollover Message Explanation Recommended Action Nov 17 09:59:09 [FVX538] [wand] [LBFO] WAN1 Test Failed 1 of 3 times_ Nov 17 09:59:39 [FVX538] [wand] [LBFO] WAN1 Test Failed 2 of 3 times_ Nov 17 10:00:09 [FVX538] [wand] [LBFO] WAN1 Test Failed 3 of 3 times_ Nov 17 10:01:01 [FVX538] [wand] [LBFO] WAN1 Test Failed 4 of 3 times_ Nov 17 10:01:35 [FVX538] [wand] [LBFO] WAN1 Test Failed 5 of 3 times_ Nov 17 10:01:35 [FVX538] [wand] [LBFO] WAN1(DOWN), WAN2(UP), ACTIVE(WAN2)_ Nov 17 10:02:25 [FVX538] [wand] [LBFO] WAN1 Test Failed 6 of 3 times_ Nov 17 10:02:25 [FVX538] [wand] [LBFO] Restarting WAN1_ Nov 17 10:02:57 [FVX538] [wand] [LBFO] WAN1 Test Failed 7 of 3 times_ Nov 17 10:03:27 [FVX538] [wand] [LBFO] WAN1 Test Failed 8 of 3 times_ Nov 17 10:03:57 [FVX538] [wand] [LBFO] WAN1 Test Failed 9 of 3 times_ Nov 17 10:03:57 [FVX538] [wand] [LBFO] Restarting WAN1_ The Logs suggest that the fail-over was detected after 5 attempts instead of 3. However, the reason the messages appear as above is because of the WAN state transition logic which is part of the failover algorithm. The above logs can be interpreted as below. The primary link failure is properly detected after the 3rd attempt. Thereafter the algorithm attempts to restart WAN and checks once again to see if WAN1 is still down. This results in the 4th failure detection message. If it is then it starts secondary link and once secondary link is up, secondary link is marked as active. Meanwhile secondary link has failed once more and that results 5th failure detection message. Please note that the 5th failure detection and the message suggesting secondary link is active have the same timestamp and so they happen in the same algorithm state-machine cycle. So although it appears that the failover did not happen immediately after 3 failures, internally, the failover process is triggered after the 3rd failure and transition to secondary link is completed by the 5th failure. The primary link is also restarted every 3 failures till it is functional again. In the above log, primary link was restarted after the 6th failure i.e. 3 failures after the failover process was triggered. Check the WAN settings and WAN failure detection method configured for the primary link. System Logs and Error Messages C-5 v1.0, March 2009

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ProSafe VPN Firewall 200 FVX538 Reference Manual
System Logs and Error Messages
C-5
v1.0, March 2009
Auto Rollover
When the WAN mode is configured for Auto Rollover, the primary link is active and secondary
acts only as a backup. When the primary link goes down, the secondary link becomes active only
until the primary link comes back up. The device monitors the status of the primary link using the
configured WAN Failure Detection method.
This section describes the logs generated when the WAN mode is set to Auto Rollover.
System Logs: WAN Status, Auto Rollover
Message
Nov 17 09:59:09 [FVX538] [wand] [LBFO] WAN1 Test Failed 1 of 3 times_
Nov 17 09:59:39 [FVX538] [wand] [LBFO] WAN1 Test Failed 2 of 3 times_
Nov 17 10:00:09 [FVX538] [wand] [LBFO] WAN1 Test Failed 3 of 3 times_
Nov 17 10:01:01 [FVX538] [wand] [LBFO] WAN1 Test Failed 4 of 3 times_
Nov 17 10:01:35 [FVX538] [wand] [LBFO] WAN1 Test Failed 5 of 3 times_
Nov 17 10:01:35 [FVX538] [wand] [LBFO] WAN1(DOWN), WAN2(UP),
ACTIVE(WAN2)_
Nov 17 10:02:25 [FVX538] [wand] [LBFO] WAN1 Test Failed 6 of 3 times_
Nov 17 10:02:25 [FVX538] [wand] [LBFO] Restarting WAN1_
Nov 17 10:02:57 [FVX538] [wand] [LBFO] WAN1 Test Failed 7 of 3 times_
Nov 17 10:03:27 [FVX538] [wand] [LBFO] WAN1 Test Failed 8 of 3 times_
Nov 17 10:03:57 [FVX538] [wand] [LBFO] WAN1 Test Failed 9 of 3 times_
Nov 17 10:03:57 [FVX538] [wand] [LBFO] Restarting WAN1_
Explanation
The Logs suggest that the fail-over was detected after 5 attempts instead of 3.
However, the reason the messages appear as above is because of the WAN
state transition logic which is part of the failover algorithm. The above logs can
be interpreted as below. The primary link failure is properly detected after the
3rd attempt. Thereafter the algorithm attempts to restart WAN and checks once
again to see if WAN1 is still down. This results in the 4th failure detection
message. If it is then it starts secondary link and once secondary link is up,
secondary link is marked as active. Meanwhile secondary link has failed once
more and that results 5th failure detection message. Please note that the 5th
failure detection and the message suggesting secondary link is active have the
same timestamp and so they happen in the same algorithm state-machine
cycle. So although it appears that the failover did not happen immediately after
3 failures, internally, the failover process is triggered after the 3rd failure and
transition to secondary link is completed by the 5th failure. The primary link is
also restarted every 3 failures till it is functional again. In the above log, primary
link was restarted after the 6th failure i.e. 3 failures after the failover process
was triggered.
Recommended Action
Check the WAN settings and WAN failure detection method configured for the
primary link.