[c-nsp] BGP and OSPF issues

[Christopher J. Wargaski]

Greetings

We have a mixed BGP and OSPF routing environment. The routing protocol
on the MPLS and point to point T-1s is mostly BGP with some OSPF (but
moving to BGP). A vendor of ours to whom we have a WAN link advertises
via OSPF (and can not advertise via BGP). This link is in a DMZ off of
the firewall which advertises the OSPF. There are backup paths to the
remote locations via VPN tunnels.

When a WAN link goes down, the lower cost BGP route (from the WAN
router) is deselected, and the higher cost OSPF route (from the
firewall) is selected. This happens dynamically.

When the WAN link comes back up the higher OSPF route is NOT
dynamically deselected in favor of the BGP route. Instead, we must
clear the OSPF process on the WAN routers.

So that every location knows all the routes, OSPF routes are
redsitributed into BGP, and BGP routes are redistributed into OSPF.

Why must I clear the OSPF process for the lower cost BGP routes to
return? Shouldn't this be dynamic? If so, is there somethign that can
be added to the configuration?


----------------------------
Firewall OSPF config:

router ospf 10
  network 10.0.2.0 255.255.255.0 area 10.0.0.0
  network 10.1.0.0 255.255.248.0 area 0
  log-adj-changes
  redistribute static metric 220 subnets route-map StaticRedistVPN

route-map StaticRedistVPN permit 8
  match metric 220

route outside 10.2.0.0 255.255.248.0 209.252.39.49 220
route outside 10.3.0.0 255.255.248.0 209.252.39.49 220

----------------------------
Router OSPF config:

router ospf 10
 log-adjacency-changes
 redistribute bgp 65002 subnets
 network 10.1.0.0 0.0.7.255 area 0
 network 192.168.1.0 0.0.0.255 area 0
 network 192.168.252.0 0.0.0.255 area 0

----------------------------
Router BGP config:

router bgp 65002
 no synchronization
 bgp log-neighbor-changes
 bgp redistribute-internal
 redistribute ospf 10 metric 200 match internal external 1
 neighbor 10.1.1.111 remote-as 65002
 neighbor 10.1.1.111 default-originate
 neighbor 10.1.1.111 version 4
 neighbor 10.1.1.111 soft-reconfiguration inbound
 distance bgp 120 120 120
 no auto-summary



cjw