Re: redistribution help

Hi Marc,

I haven't reviewed your configs yet, but started to work on a solution
on my own. The RIB seems to be stable according to "debug ip routing"
and I have full reachability.

Instead of using tagging, I just tried to protect the lower AD routes in
the RIB on border routers that are doing the redistribution.

Here is a short summary of what I did:

R1
==

- OSPF distribute list: Filter EIGRP external (AD 170) and RIP (AD 120)
prefixes from entering RIB with AD of 110
- RIP distance 190: Protect external EIGRP routes when learned via RIP
from R2
- RIP distance 120 from R4: Original RIP prefixes should keep AD of 120

R2
==

- OSPF distribute list: Filter RIP (AD 120) prefixes from entering RIB
with AD of 110 when learned from another OSPF router

R3
==

- OSPF distribute list: Filter EIGRP external (AD 170) from entering RIB
with AD of 110 when learned from another OSPF router

Filter config
-------------

R1

ip prefix-list PL_EIGRP_EXT permit 172.20.106.0/24
ip prefix-list PL_EIGRP_EXT permit 6.6.6.0/24
!
ip prefix-list PL_RIP permit 172.20.104.0/24
ip prefix-list PL_RIP permit 4.4.4.0/24
!
route-map OSPF_RIB_FILTER deny 10
 match ip addr prefix PL_EIGRP_EXT
route-map OSPF_RIB_FILTER deny 20
 match ip addr prefix PL_RIP
route-map OSPF_RIB_FILTER permit 1000
!
router ospf 1
 distribute-list route-map OSPF_RIB_FILTER in
!
ip access-list standard RIP_PREFIXES
 permit 172.20.104.0 0.0.0.255
 permit 4.4.4.0 0.0.0.255
!
router rip
 distance 190
 distance 120 172.20.124.4 0.0.0.0 RIP_PREFIXES

R2

ip prefix-list PL_RIP permit 172.20.104.0/24
ip prefix-list PL_RIP permit 4.4.4.0/24
!
route-map OSPF_RIB_FILTER deny 10
 match ip addr prefix PL_RIP
route-map OSPF_RIB_FILTER permit 1000
!
router ospf 1
 distribute-list route-map OSPF_RIB_FILTER in

R3

ip prefix-list PL_EIGRP_EXT permit 172.20.106.0/24
ip prefix-list PL_EIGRP_EXT permit 6.6.6.0/24
!
route-map OSPF_RIB_FILTER deny 10
 match ip addr prefix PL_EIGRP_EXT
route-map OSPF_RIB_FILTER permit 1000
!
router ospf 1
 distribute-list route-map OSPF_RIB_FILTER in

Best regards,

Jochen

Blogs and organic groups at http://www.ccie.net
Received on Sat Feb 25 2012 - 22:15:27 ART