OSPF on SHDSL

[dulem]

Hello Guys

I have very strange problem to setup very simple OSPF between 3 routers in hub-spoke scenario.
Here is config from hub router in main office:

interface ATM0/1/0
no ip address
ip directed-broadcast
ip pim sparse-mode
no atm ilmi-keepalive
!
interface ATM0/1/0.1 point-to-point
ip address x.x.x.x 255.255.255.252
ip ospf network broadcast
ip ospf priority 50
pvc 0/35
encapsulation aal5snap
!
!
interface ATM0/1/0.2 point-to-point
ip address x.x.x.y 255.255.255.252
ip directed-broadcast
ip ospf network broadcast
ip ospf priority 50
pvc 0/36
encapsulation aal5snap


router ospf 10
log-adjacency-changes
network x.x.x.x 0.0.0.7 area 0
network 192.168.x.0 0.0.0.255 area 0

On the one of remote routers config is following:

interface ATM0/0/0
ip address x.x.x.x 255.255.255.252
ip directed-broadcast
ip ospf network broadcast
atm ilmi-keepalive 3
pvc 0/35
encapsulation aal5snap
!
!
router ospf 10
log-adjacency-changes
network x.x.x.x 0.0.0.3 area 0
network 192.168.y.0 0.0.0.255 area 0


Here is problem:

OSPF communication is established for the first time and after dead timer expire (in 40 sec) connection is broken and is reestablished after 10 sec. So it produce route flapping.

It is appear only on HO router and it constantly flap routes. For the remote site router everything appear OK.

I ran debug ip ospf events and got that HO router is sending hello packets but not receiving any ospf hello packet.

On the remote router hello packets are sent and received and there is no problem with routes.

TIA

 

[jneiberger]

Why are you using "ip ospf network broadcast"? It's been a while since I did OSPF, but I think you'd get better results with point-to-point.

 

[dulem]

When I configure point-to-point ospf is not establishing at all.

 

[jneiberger]

Maybe try point-to-multipoint and then manually configure your neighbors. Or, move the ATM config on your remote router from the main interface and put it on a point-to-point subinterface like you're doing at the hub.

 

[burtsbees]

I agree with jneiberger---this is NBMA...

Burt