09-20-2018 05:56 AM
For years, I have setup IP SLAs and tracked them for different purposes. The problem is that some of the IP addresses that I have been monitoring have actually had outages as well. In comes the Boolean or. It is possible to create multiple SLAs, and then setup a Boolean or to track those SLAs. You can then failover if two SLAs go down at the same time. This has already increased our uptime in my own environment and I think that this should become the standard for tracking internet circuits, etc.
Here is an example:
track 1 ip sla 1 reachability
!
track 2 ip sla 2 reachability
!
track 3 list boolean or
object 1
object 2
If track 1 goes down, track 3 will remain online. If track 2 goes down, track 3 will remain online. If track 1 and 2 go down, track 3 will go down, and you can react to that. The idea is that the possibility of 2 IP addresses being down at the same time should be a lot less of a probability than 1 IP. The Boolean or is an easy way to make better decisions on when a circuit is truly down. This is just one use case.
Please let me know if you have any thoughts!
09-24-2018 02:57 PM
How does the boolean "and" "or" work
to me it seems logical that in your example if 1 or 2 went down then it would trigger as you used "or" and if you used "and" then both 1 and 2 would be needed to trigger it.
09-24-2018 05:20 PM
09-26-2018 01:07 PM
Yes, I was looking at the logic differently as well.
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