L operator, topology is NE20 (Version 3.30-0330.23)－－ATM (transmission)－－AR46. New ATM transmission is enabled. AR46 can be pinged from NE20, but OSPF neighbor relation cannot be established. NE20 cannot learn the route to AR46.
1. After log on the device, NE20 can ping through AR46 interface address and the link is smooth.
2. Check OSPF PEER and it is found that OSPF state keeps EXCHANGE.
3. NE20 pings AR46 interface address. Add -s parameter and test link quality. The packet with 766 can be pinged, but the packet with 767 is discarded.
4. The link quality is problematic, but user's transmission department responds there is no transmission alarm.
5. Check configuration and it is found that NE20 configures "service cbr 2000" (2M bandwidth configuration). Use CBR as service type of PVC to define rate.
6. Observe routing table and it is found that NE20 has learnt the route of AR46 and OSPF reaches full state.
The link is smooth, but OSPF neighbor cannot reach full state. It is possible that OSPF process is problematic or OSPF negotiation packet is not sent to the opposite.
OSPF does not reach full state. The reason is that it does not receive opposite negotiation packet. It is in EXCHANGE.