Cisco to Juniper (Junos) Redistributing EIGRP to OSPF

In my previous post,

Redistribute EIGRP and OSPF / Route Tagging

I talked about route tagging, but it works only for internal routes redistributing from EIGRP to OSPF.

A problem comes up when you're redistributing from EIGRP to OSPF with external routes, ie. external EIGRP.
This is when you use the redistribute command in EIGRP, which gives AD of 170.  To solve this, you'll need to add:

distance ospf external 171

in the router ospf 1 process.  Do a "show ip route ospf" in the core router that does the EIGRP/OSPF redistribution to see the difference.

To simulate:

Router 4 / router 6 / other normal router:

router eigrp 2
 network 172.17.39.0 0.0.0.3
 redistribute connected 
 redistribute static     === The redistribute command will have the AD of 170 (external EIGRP).  Internal EIGRP is 90 with the "network" command.

Router 2:  == This is the router that does the EIGRP/OSPF redistribution and connected to the JUNIPER.

router eigrp 2
 network 172.17.0.0
 redistribute ospf 1 metric 100000 1 255 1 1500 route-map OSPF-TO-EIGRP
router ospf 1
 router-id 2.2.2.2
 log-adjacency-changes
 redistribute eigrp 2 subnets route-map EIGRP-TO-OSPF
 network 172.17.34.0 0.0.0.3 area 0
 default-information originate
 distance ospf external 171    === Need this on the router that does the EIGRP/OSPF redistribution.  Else traffic FROM EIGRP domain GOING TO another EIGRP domain that did the REDISTRIBUTE STATIC, etc. will take the path of OSPF, and not through the EIGRP to EIGRP.


Router 3: == The core router that does the EIGRP/OSPF redistribution and connected to the JUNIPER.

router eigrp 2
 network 172.17.0.0
 redistribute ospf 1 metric 100000 1 255 1 1500 route-map OSPF-TO-EIGRP
router ospf 1
 router-id 3.3.3.3
 log-adjacency-changes
 redistribute eigrp 2 subnets route-map EIGRP-TO-OSPF
 network 172.17.35.0 0.0.0.3 area 0
 default-information originate
 distance ospf external 171   === Need this on the router that does the EIGRP/OSPF redistribution.  Else traffic FROM EIGRP domain GOING TO another EIGRP domain that did the REDISTRIBUTE STATIC, etc. will take the path of OSPF, and not through the EIGRP to EIGRP.


Both R2 and R3# sh ip ro os   === WILL SHOW THE SAME OSPF route to the OSPF domain.

Gateway of last resort is 172.17.32.1 to network 0.0.0.0

      192.168.60.0/32 is subnetted, 1 subnets
O        192.168.60.1 [110/3] via 172.17.34.1, 2d01h, FastEthernet1/0
R2#