Hello Experts,
Below is a simple topology with R1 participating in Area 0 and Area 4(configured for NSSA) and R2 participating in Area 4.
R1 being the NSSA ABR/ASBR is redistributing a default route and a bunch of other static routes configured locally using the 'ospf export' command.
static route redistribution
|
|
(Area0) R1 (Area4) ---- (Area4) R2
Per RFC 3101 since R1 is also connected to another area and is redistributing a route from another protocol (static) it is clearing the P-bit in the Type-7 LSA's sent towards R2 to avoid further propagation to its connected areas.
All works fine and we are observing a type-7 default route alongwith the redistributed static routes in the ospf database and subsequently in the routing table.
Now when i enable any random interface on R2 to participate in any other area apart from area 4, i lose only the default route in the routing table but not the other static routes from the same type-7 LSA's.
Upon looking in the database on R2, i can find the type-7 default route along with the other type-7 routes redistributed from R1, with the same values in the options field, but only the default route is withdrawn from the routing table.
Upon de-activation of the recent change, the default route gets re-installed.
This behaviour is seen in the customer topology with R1 being a MX960 and R2 being a QFX5100.
The same was replicated in the LAB using R1 & R2 as EX3300.
Is this an expeteced behaviour of withdrawing only the default route, but keeping all other Type-7 routes, from the routing table when a NSSA ASBR is connected to multiple areas?
Any help is appreciated. Thank you in advance !
*Note: Configuration files & ospf database outputs uploaded and named accordingly.