Protocols/BGP_OSPF_MPLS_VPN
OSPF Link-state/Adjacency changes
양된백성
2021. 2. 16. 16:46
<OSPF Neighbor State Changes>
OSPF has a link-state with neighbors. each state from Down to Full is changed with packets establishing a neighbor.
if your OSPF neighbor does not come up to FULL state, you can make the troubleshooting closer by looking for the stuck state.
<Understanding OSPF adjacency in Broadcast network>
1. Shutdown each interface on R1, R2, R3
| R1(config)#int e 0/0.123 R1(config-subif)#sh |
| R2(config)#int e 0/0.123 R2(config-subif)#sh |
| R3(config)#int e 0/0.123 R3(config-subif)#shutdown |
2. Turn on Debug on R1
| R1#debug ip ospf adj OSPF adjacency debugging is on |
3. No shutdown each interface on R1, R2, R3
| R1(config)#int e 0/0.123 R1(config-subif)#no sh |
| R2(config)#int e 0/0.123 R2(config-subif)#no sh |
| R3(config)#int e 0/0.123 R3(config-subif)#no sh |
4. Debug messages for link-state changes
| R1(config-subif)# *Feb 16 07:23:06.424: OSPF-1 ADJ Et0/0.123: Route adjust notification: UP/UP *Feb 16 07:23:06.425: OSPF-1 ADJ Et0/0.123: Interface going Up *Feb 16 07:23:06.425: OSPF-1 ADJ Et0/0.123: Interface state change to UP, new ospf state WAIT *Feb 16 07:23:16.099: OSPF-1 ADJ Et0/0.123: 2 Way Communication to 1.1.3.3, state 2WAY *Feb 16 07:23:16.099: OSPF-1 ADJ Et0/0.123: 2 Way Communication to 1.1.2.2, state 2WAY R1(config-subif)# R1(config-subif)#do show ip ospf neigh Neighbor ID Pri State Dead Time Address Interface 1.1.2.2 1 2WAY/DROTHER 00:00:34 1.1.123.2 Ethernet0/0.123 // R1 is 2WAY state with both R2 and R3. 1.1.3.3 1 2WAY/DROTHER 00:00:35 1.1.123.3 Ethernet0/0.123 // not DR and BDR election yet R1(config-subif)# *Feb 16 07:23:46.430: OSPF-1 ADJ Et0/0.123: end of Wait on interface // Wait time for 40sec before electing DR/BDR *Feb 16 07:23:46.430: OSPF-1 ADJ Et0/0.123: DR/BDR election *Feb 16 07:23:46.430: OSPF-1 ADJ Et0/0.123: Elect BDR 1.1.3.3 *Feb 16 07:23:46.430: OSPF-1 ADJ Et0/0.123: Elect DR 1.1.3.3 *Feb 16 07:23:46.430: OSPF-1 ADJ Et0/0.123: DR: 1.1.3.3 (Id) *Feb 16 07:23:46.430: OSPF-1 ADJ Et0/0.123: BDR: 1.1.3.3 (Id) *Feb 16 07:23:46.430: OSPF-1 ADJ Et0/0.123: Nbr 1.1.3.3: Prepare dbase exchange *Feb 16 07:23:46.430: OSPF-1 ADJ Et0/0.123: Send DBD to 1.1.3.3 seq 0x1D48 opt 0x52 flag 0x7 len 32 *Feb 16 07:23:47.778: OSPF-1 ADJ Et0/0.123: Rcv DBD from 1.1.3.3 seq 0x1704 opt 0x52 flag 0x7 len 32 mtu 1500 state EXSTART *Feb 16 07:23:47.778: OSPF-1 ADJ Et0/0.123: NBR Negotiation Done. We are the SLAVE *Feb 16 07:23:47.778: OSPF-1 ADJ Et0/0.123: Nbr 1.1.3.3: Summary list built, size 18 *Feb 16 07:23:47.778: OSPF-1 ADJ Et0/0.123: Send DBD to 1.1.3.3 seq 0x1704 opt 0x52 flag 0x2 len 392 *Feb 16 07:23:47.779: OSPF-1 ADJ Et0/0.123: Rcv DBD from 1.1.3.3 seq 0x1705 opt 0x52 flag 0x1 len 72 mtu 1500 state EXCHANGE *Feb 16 07:23:47.779: OSPF-1 ADJ Et0/0.123: Exchange Done with 1.1.3.3 *Feb 16 07:23:47.779: OSPF-1 ADJ Et0/0.123: Send LS REQ to 1.1.3.3 length 36 *Feb 16 07:23:47.779: OSPF-1 ADJ Et0/0.123: Send DBD to 1.1.3.3 seq 0x1705 opt 0x52 flag 0x0 len 32 *Feb 16 07:23:47.780: OSPF-1 ADJ Et0/0.123: Rcv LS UPD from Nbr ID 1.1.3.3 length 64 LSA count 1 *Feb 16 07:23:47.780: OSPF-1 ADJ Et0/0.123: Synchronized with 1.1.3.3, state FULL *Feb 16 07:23:47.780: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.3.3 on Ethernet0/0.123 from LOADING to FULL, Loading Done *Feb 16 07:23:47.780: OSPF-1 ADJ Et0/0.123: Rcv LS REQ from 1.1.3.3 length 132 LSA count 9 *Feb 16 07:23:54.579: OSPF-1 ADJ Et0/0.123: Neighbor change event *Feb 16 07:23:54.579: OSPF-1 ADJ Et0/0.123: DR/BDR election *Feb 16 07:23:54.579: OSPF-1 ADJ Et0/0.123: Elect BDR 1.1.3.3 *Feb 16 07:23:54.579: OSPF-1 ADJ Et0/0.123: Elect DR 1.1.3.3 *Feb 16 07:23:54.579: OSPF-1 ADJ Et0/0.123: DR: 1.1.3.3 (Id) *Feb 16 07:23:54.579: OSPF-1 ADJ Et0/0.123: BDR: 1.1.3.3 (Id) *Feb 16 07:23:54.579: OSPF-1 ADJ Et0/0.123: Neighbor change event *Feb 16 07:23:54.579: OSPF-1 ADJ Et0/0.123: DR/BDR election *Feb 16 07:23:54.579: OSPF-1 ADJ Et0/0.123: Elect BDR 1.1.3.3 *Feb 16 07:23:54.579: OSPF-1 ADJ Et0/0.123: Elect DR 1.1.3.3o *Feb 16 07:23:54.579: OSPF-1 ADJ Et0/0.123: DR: 1.1.3.3 (Id) *Feb 16 07:23:54.579: OSPF-1 ADJ Et0/0.123: BDR: 1.1.3.3 (Id) *Feb 16 07:23:55.728: OSPF-1 ADJ Et0/0.123: Neighbor change event *Feb 16 07:23:55.728: OSPF-1 ADJ Et0/0.123: DR/BDR election *Feb 16 07:23:55.728: OSPF-1 ADJ Et0/0.123: Elect BDR 1.1.2.2 *Feb 16 07:23:55.728: OSPF-1 ADJ Et0/0.123: Elect DR 1.1.3.3 *Feb 16 07:23:55.728: OSPF-1 ADJ Et0/0.123: DR: 1.1.3.3 (Id) *Feb 16 07:23:55.728: OSPF-1 ADJ Et0/0.123: BDR: 1.1.2.2 (Id) *Feb 16 07:23:55.728: OSPF-1 ADJ Et0/0.123: Nbr 1.1.2.2: Prepare dbase exchange *Feb 16 07:23:55.728: OSPF-1 ADJ Et0/0.123: Send DBD to 1.1.2.2 seq 0x1EB opt 0x52 flag 0x7 len 32 *Feb 16 07:23:55.728: OSPF-1 ADJ Et0/0.123: Neighbor change event *Feb 16 07:23:55.728: OSPF-1 ADJ Et0/0.123: DR/BDR election *Feb 16 07:23:55.728: OSPF-1 ADJ Et0/0.123: Elect BDR 1.1.2.2 *Feb 16 07:23:55.728: OSPF-1 ADJ Et0/0.123: Elect DR 1.1.3.3 *Feb 16 07:23:55.728: OSPF-1 ADJ Et0/0.123: DR: 1.1.3.3 (Id) *Feb 16 07:23:55.728: OSPF-1 ADJ Et0/0.123: BDR: 1.1.2.2 (Id) *Feb 16 07:23:55.729: OSPF-1 ADJ Et0/0.123: Rcv DBD from 1.1.2.2 seq 0x18DE opt 0x52 flag 0x7 len 32 mtu 1500 state EXSTART *Feb 16 07:23:55.729: OSPF-1 ADJ Et0/0.123: NBR Negotiation Done. We are the SLAVE *Feb 16 07:23:55.729: OSPF-1 ADJ Et0/0.123: Nbr 1.1.2.2: Summary list built, size 18 *Feb 16 07:23:55.729: OSPF-1 ADJ Et0/0.123: Send DBD to 1.1.2.2 seq 0x18DE opt 0x52 flag 0x2 len 392 *Feb 16 07:23:55.729: OSPF-1 ADJ Et0/0.123: Rcv DBD from 1.1.2.2 seq 0x18DF opt 0x52 flag 0x1 len 52 mtu 1500 state EXCHANGE *Feb 16 07:23:55.729: OSPF-1 ADJ Et0/0.123: Exchange Done with 1.1.2.2 *Feb 16 07:23:55.729: OSPF-1 ADJ Et0/0.123: Synchronized with 1.1.2.2, state FULL *Feb 16 07:23:55.729: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.2.2 on Ethernet0/0.123 from LOADING to FULL, Loading Done *Feb 16 07:23:55.729: OSPF-1 ADJ Et0/0.123: Send DBD to 1.1.2.2 seq 0x18DF opt 0x52 flag 0x0 len 32 R1(config-subif)#do show ip ospf neigh Neighbor ID Pri State Dead Time Address Interface 1.1.2.2 1 FULL/BDR 00:00:35 1.1.123.2 Ethernet0/0.123 1.1.3.3 1 FULL/DR 00:00:35 1.1.123.3 Ethernet0/0.123 R1(config-subif)# |
| R1#show ip ospf int e 0/0.123 Ethernet0/0.123 is up, line protocol is up Internet Address 1.1.123.1/24, Area 1, Attached via Network Statement Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 10 Topology-MTID Cost Disabled Shutdown Topology Name 0 10 no no Base Transmit Delay is 1 sec, State DROTHER, Priority 1 Designated Router (ID) 1.1.3.3, Interface address 1.1.123.3 Backup Designated router (ID) 1.1.2.2, Interface address 1.1.123.2 Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 //"Wait" indicates how long to wait if the DR fails until the election process begins in order to replace the DR. oob-resync timeout 40 Hello due in 00:00:07 Supports Link-local Signaling (LLS) Cisco NSF helper support enabled IETF NSF helper support enabled Index 1/2/2, flood queue length 0 Next 0x0(0)/0x0(0)/0x0(0) Last flood scan length is 1, maximum is 5 Last flood scan time is 0 msec, maximum is 1 msec Neighbor Count is 2, Adjacent neighbor count is 2 Adjacent with neighbor 1.1.2.2 (Backup Designated Router) Adjacent with neighbor 1.1.3.3 (Designated Router) Suppress hello for 0 neighbor(s) |
<Understanding OSPF adjacency in Point-To-Point network>
1. Shutdown each interface on R4
| R4(config)#int s 1/2 R4(config-if)#sh |
2. Turn on Debug on R4 for OSPF Adjacency
| R4(config-if)#no debug ip ospf adj OSPF adjacency debugging is on |
3. No shutdown each interface on R4
| R4(config)#int s 1/2 R4(config-if)#no sh |
4. Debug messages for link-state changes
| R4(config-if)# *Feb 16 07:39:44.442: %LINK-3-UPDOWN: Interface Serial1/2, changed state to up *Feb 16 07:39:45.442: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/2, changed state to up *Feb 16 07:39:45.442: OSPF-1 ADJ Se1/2: Route adjust notification: UP/UP *Feb 16 07:39:45.442: OSPF-1 ADJ Se1/2: Interface going Up *Feb 16 07:39:45.442: OSPF-1 ADJ Se1/2: Interface state change to UP, new ospf state P2P *Feb 16 07:39:45.455: OSPF-1 ADJ Se1/2: 2 Way Communication to 1.1.3.3, state 2WAY *Feb 16 07:39:45.455: OSPF-1 ADJ Se1/2: Nbr 1.1.3.3: Prepare dbase exchange *Feb 16 07:39:45.455: OSPF-1 ADJ Se1/2: Send DBD to 1.1.3.3 seq 0xE53 opt 0x52 flag 0x7 len 32 *Feb 16 07:39:45.465: OSPF-1 ADJ Se1/2: Rcv DBD from 1.1.3.3 seq 0x3BC opt 0x52 flag 0x7 len 32 mtu 1500 state EXSTART *Feb 16 07:39:45.465: OSPF-1 ADJ Se1/2: First DBD and we are not SLAVE *Feb 16 07:39:45.465: OSPF-1 ADJ Se1/2: Rcv DBD from 1.1.3.3 seq 0xE53 opt 0x52 flag 0x2 len 232 mtu 1500 state EXSTART *Feb 16 07:39:45.465: OSPF-1 ADJ Se1/2: NBR Negotiation Done. We are the MASTER *Feb 16 07:39:45.465: OSPF-1 ADJ Se1/2: Nbr 1.1.3.3: Summary list built, size 10 *Feb 16 07:39:45.466: OSPF-1 ADJ Se1/2: Send DBD to 1.1.3.3 seq 0xE54 opt 0x52 flag 0x1 len 72 *Feb 16 07:39:45.476: OSPF-1 ADJ Se1/2: Rcv LS REQ from 1.1.3.3 length 36 LSA count 1 *Feb 16 07:39:45.476: OSPF-1 ADJ Se1/2: Send LS UPD to 1.1.34.3 length 76 LSA count 1 *Feb 16 07:39:45.476: OSPF-1 ADJ Se1/2: Rcv DBD from 1.1.3.3 seq 0xE54 opt 0x52 flag 0x0 len 32 mtu 1500 state EXCHANGE *Feb 16 07:39:45.476: OSPF-1 ADJ Se1/2: Exchange Done with 1.1.3.3 *Feb 16 07:39:45.476: OSPF-1 ADJ Se1/2: Synchronized with 1.1.3.3, state FULL *Feb 16 07:39:45.476: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.3.3 on Serial1/2 from LOADING to FULL, Loading Done R4(config-if)# |
| R4(config-if)#do show ip ospf nei Neighbor ID Pri State Dead Time Address Interface 1.1.3.3 0 FULL/ - 00:00:30 1.1.34.3 Serial1/2 // No DR, BDR election. 1.1.2.2 1 FULL/BDR 00:00:39 1.1.24.2 Ethernet0/0.24 1.1.5.5 1 FULL/DR 00:00:35 1.1.45.5 Ethernet0/0.45 |