Have You Realized The Importance Of The Boolean Or For Tracking?

[Alex Pfeil]

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! 

[Richard Bradfield]

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.

[Richard Bradfield]

Y

OK I was looking at logic the other way round, this is how it works

with a Boolean “AND” function requires that each object in the list be in an up state for the tracked object

to be up. A tracked list with a Boolean “OR” function needs only one object in the list to be in the up state for the tracked object to be up.

[Alex Pfeil]

Yes, I was looking at the logic differently as well.