Configuring Nexus 7000 vPC Peer Links and Links to the Core on a Single Module

[Roman Rodichev]

In reference to:

http://www.cisco.com/en/US/docs/switches/datacenter/sw/5_x/nx-os/interfaces/configuration/guide/if_vPC.html#wp1803985

In my situation I have a single 8-gig module in each Nexus7k. 10/1 and 10/2 are in PC100 peer-link. 10/3 connects to the core. 10/3 is a vPC102 on Nexus A and B.

Would it be more appropirated to use boolean AND or OR? Documentation states we should use OR, but I think AND makes more sense.

track 1 interface port-channel 100 line-protocol

track 2 interface ethernet10/3 line-protocol

!

track 10 list boolean AND

object 1

object 2

end

!

vpc domain 1

track 10

I don't want VPC failover to occur only if E10/3 core interface fails. If use "OR" as in documentation, that's what would happen. Not sure why you would want failover to happen in that case.

I only want failover when the entire module 10 fails so both PO100 and E10/3 would fail causing VPC domain to failover to the second peer. In other words, AND boolean would apply better?

The second clarification. I beleive I need this only one the primary VPC domain peer. I don't need this on the secondary VPC domain peer, correct?

[Andrew Gossett · Accepted solution]

Hi Roman,

To achieve the behavior you described, you will want to use the OR statement as dictated in the configuration guide.  Since you are tracking link-status in each object, consider the link up as a boolean 1 and the link down as a boolean 0.  The tracking list triggers if it evaulates to 0.  Thus:

scenario 1:

object 1 is up, object 2 is up

OR    List = 1 OR 1 = 1

AND  List = 1 AND 1 = 1

#######################################

scenario 2:

object 1 is up, object 2 is down

OR    List = 1 OR 0 = 1

AND  List = 1 AND 0 = 0   <---- track list is triggered

#######################################

scenario 3:

object 1 is down, object 2 is up

OR    List = 0 OR 1 = 1

AND  List = 0 AND 1 = 0  <----- track list is triggered

#######################################

scenario 4:

object 1 is down, object 2 is down

OR    List = 0 OR 0 = 0    <------ track list is triggered

AND  List = 0 AND 0 = 0  <------ track list is triggered

If the desired behavior is to trigger the track list only when all links go down, then you will want to use the OR operator.  I hope this clarifies your question.

-Andy

[Roman Rodichev]

Andrew, thank you, I get it now. I've been confusing it with "match-all" and "match-any" logic. I was seeing "boolean", but not thinking in "boolean". It makes sense now, I do need OR.