Question about route-map logic

 

The sample as below

match ip add ACCESS-LIST

set ip next-hop verify-availability 2.2.2.2 track 1

set ip next-hop 3.3.3.3

track 1 just monitor icmp-echo sla

The testing result shows if the routing to 2.2.2.2 is up the second "set" won't override the first "set". However if the rouitng to 2.2.2.2 down, the second "set" will take place.

So, what's the relationship between the first "set" and the second "set"? AND or OR?

 

Comments

  • areu sure that statement is working? can duouble check route map

  • i'm sure, because i followed ine rsv5 workbook and the difference is INE uses ip next-hop default and i just use ip next-hop

  • there is difference betwen having default and not having default

    with default = RIB first but do not use default route, then PBR if RIB fails

    without default =PBR first then RIB

    AND does not make sense with multiple set statements; I think when tracking object is up, 2nd set does not matter.  if tracking object is down, then 2nd set is used;

     

  • Yes, that's why i'm confused. Below is the answer from the workbook. Initially I thought the 2nd "set" will override the 1st "set" because they are trying to "set" the same attribute, but it seems not working that way.

    route-map POLICY_ROUTING permit 10
     match ip address FROM_R4
     set ip next-hop verify-availability 155.1.13.3 1 track 1
     set ip default next-hop 155.1.0.5
  • Basically this feature reads a little different that your bog standard route-map logic:

     

    route-map POLICY_ROUTING permit 10
     match ip address FROM_R4
     set ip next-hop verify-availability 155.1.13.3 1 track 1  <- RIB lookup.
     set ip default next-hop 155.1.0.5 <- Non RIB lookup, interrupt driven


    Reads if there is not a match on the prefix list then route as normal, i.e. exit the route-map

    if there is a match in the prefix list look in the RIB for 155.1.13.3 and route that way, if the SLA is up.
      else
        do not look further in the RIB for a less match but 'force' the route towards 155.1.0.5

  • I think this is related to pbr. Check this article for order of operation regarding route-maps used by pbr. 

     

    http://brbccie.blogspot.hu/2014/10/mini-fail-over-policy-based-routing.html

  • and you misssed 1 in set ip next-hop verify-availability 2.2.2.2 track 1

    between 2 and track, my routers says u need an entry

    set ip next-hop verify-availability 2.2.2.2  x  track 1

Sign In or Register to comment.