Question about route-map logic

nyx01xnyx

 

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?

 

MartinLosik

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

nyx01xnyx

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

MartinLosik

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;

 

nyx01xnyx

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

[email protected]

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

fkuris

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

MartinLosik

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