OSPF <--> EIGRP Redistribution



  • I am working on setting up a secondary link between two of our sites. The two sites currently connect via AT&T Opt-E-Man service. Since the two sites are a only a few blocks apart, we are going to use a pair of Ubiquiti AirFiber radios to put up this secondary (which will actually become our primary) link.

    Because of the organization I work for, I need to encrypt the traffic flowing across the radio link. We purchased a pair of Ubiquiti ERPro8's, and I've got the VPN tunnel set up and working beautifully. I also have OSPF working between the two routers as well, so the VPN tunnel is more-or-less seamless to connecting devices.

    The remainder of our network is composed of various Cisco gear, which means we are using EIGRP. So, I need to 1) redistribute EIGRP over OSPF so the ERPro's are aware of our network, and 2) redistribute OSPF over EIGRP so that the rest of our network is aware of the ERPro routes. The idea is that with dynamic routing we can automagically "fall back" to the Opt-E-Man circuit if anything happened to the radio link (hardware failure, alignment issue, etc).

    I have EIGRP redistrubuting over OSPF beautifully. However, I cannot seem to get OSPF to redistribute over EIGRP. The neighboring device is getting OSPF updates without issue, but doesn't seem to be redistributing them over EIGRP. Here are the EIGRP and OSPF configurations on the neighboring switch that is to do the redistribution:

    router eigrp 100
    redistribute static
    redistribute ospf 3
    no auto-summary
    no eigrp log-neighbor-changes
    network 10.0.0.0
    network 172.19.0.0

    router ospf 3
    router-id 10.39.11.1
    log-adjacency-changes
    redistribute static subnets
    redistribute eigrp 100 subnets
    passive-interface default
    no passive-interface GigabitEthernet0/5
    network 10.39.11.0 0.0.0.3 area 0
    default-information originate always

    Any ideas?



  • I got my answer. It turns out OSPF applies a default metric to readvertised EIGRP routes, but EIGRP does not apply a default metric to readvertised OSPF routes. So I modified my EIGRP config like so:

    router eigrp 100
    redistribute static
    redistribute ospf 3 metric 1000000 0 255 1 1500
    no auto-summary
    no eigrp log-neighbor-changes
    network 10.0.0.0
    network 172.19.0.0

    BOOM, works!


Log in to reply