I have the following topology:
ignore the ...'s. Had to put them there for formatting
RA ------------ RB
RA and ISPA are EBGP peers
RB and ISPB are EBGP peers
RA and RB are IBGP peers
ISPA - 172.16.1.1
RA - 172.16.1.2, 192.168.1.1
RB - 192.168.1.2, 10.1.1.2
I want redistribute a default network, advertised from my ISP's, into my core. The core is running EIGRP.
I want clients that are closer to RA to exit via ISPA and clients closer to RB to exit via ISPB.
I want RA to redistribute the default from ISPA and RB to redistribute the default from ISPB. Then, my downstream clients can head toward the closest exit point.
Here is the problem:
ISPB is down.
RA learns the default route from the ebgp connection with ISPA and enters the route in it's routing table. It redistributes the default route into EIGRP.
RB leans the default route through EIGRP and enters the route into the routing table as an external EIGRP route.
Now, when ISPB come back up, RB shows the default route from ISPB in its BGP table, but RB will not replace the external EIGRP route currently in the routing table.
The default route RB learns from ISPB is from an EBGP connection and has an admin distance of 20 compared to the admin distance of 170 from the external EIGRP route it learns from RA. So, why won't RB update the routing table with the BGP route?