04-29-2023 05:57 AM
Subject: Need help configuring OSPF on a multi-router network
Hello,
I'm having some trouble configuring OSPF on my network, and I'm hoping someone can help me out. I have several routers connected together, each with their own VLANs in different networks. I want to be able to route traffic between these VLANs using OSPF.
I've tried setting up OSPF using the commands "router ospf 1", " and adding the addresses of the sub interfaces , but there are no adjacencies being formed
Here's a diagram of my network:
Can anyone help me figure out what I'm doing wrong? I can provide more details about my configuration if needed.
Thanks in advance for any help you can provide!
04-29-2023 06:50 AM
Hello,
If you enabled "router ospf 1" On each router, what you need to do now is advertise the OSPF on every interface.
You can do this by using the interface network.
router osp1
network x.x.x.x x.x.x.x (wildcard mask) area 0
Then you can use a command to simplify you configuration, which is:
redistribute connected.
After that, you only nee to check in each router with the command:
show ip ospf nei
and show ip route ospf
04-29-2023 07:00 AM
ive done this but i want to advertise the routes of the different vlans but nothing happens
04-29-2023 07:20 AM
You need to check first the adjacency. If you have neighbor, you are good.
Then, you add the command network in order to advertise.
But, you need to use Area 0 (Zero) .
04-29-2023 07:04 AM
Can you share config as text
04-29-2023 07:13 AM
Router ospf 1
Network 172.16.16.0 0.0.0.255 area 1
Network 172.16.17.0 0.0.0.255 area 1
Network 172.16.18.0 0.0.0.255 area 1
this is the routes for the sub interfaces
04-29-2023 07:17 AM
Router#show ip ospf
Routing Process "ospf 1" with ID 1.0.0.0
FastEthernet0/0.1 is up, line protocol is up
Internet address is 172.16.16.1/24, Area 1
Process ID 1, Router ID 1.0.0.0, Network Type BROADCAST, Cost: 1
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 1.0.0.0, Interface address 172.16.16.1
No backup designated router on this network
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:08
Index 1/1, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 0, Adjacent neighbor count is 0
Suppress hello for 0 neighbor(s)
FastEthernet0/0.2 is up, line protocol is up
Internet address is 172.16.17.1/24, Area 1
Process ID 1, Router ID 1.0.0.0, Network Type BROADCAST, Cost: 1
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 1.0.0.0, Interface address 172.16.17.1
No backup designated router on this network
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:08
Index 2/2, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 0, Adjacent neighbor count is 0
Suppress hello for 0 neighbor(s)
FastEthernet0/0.3 is up, line protocol is up
Internet address is 172.16.18.1/24, Area 1
Process ID 1, Router ID 1.0.0.0, Network Type BROADCAST, Cost: 1
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 1.0.0.0, Interface address 172.16.18.1
No backup designated router on this network
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:08
Index 3/3, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 0, Adjacent neighbor count is 0
Suppress hello for 0 neighbor(s)
Serial0/1/0 is up, line protocol is up
Internet address is 1.0.0.1/30, Area 1
Process ID 1, Router ID 1.0.0.0, Network Type POINT-TO-POINT, Cost: 64
Transmit Delay is 1 sec, State POINT-TO-POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:04
Index 4/4, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 1 , Adjacent neighbor count is 1
Adjacent with neighbor 1.0.0.5
Suppress hello for 0 neighbor(s)
Serial0/1/1 is up, line protocol is up
Internet address is 1.0.0.29/30, Area 1
Process ID 1, Router ID 1.0.0.0, Network Type POINT-TO-POINT, Cost: 64
Transmit Delay is 1 sec, State POINT-TO-POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:06
Index 5/5, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 1 , Adjacent neighbor count is 1
Adjacent with neighbor 1.0.0.30
Suppress hello for 0 neighbor(s)
Supports only single TOS(TOS0) routes
Supports opaque LSA
SPF schedule delay 5 secs, Hold time between two SPFs 10 secs
Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs
Number of external LSA 0. Checksum Sum 0x000000
Number of opaque AS LSA 0. Checksum Sum 0x000000
Number of DCbitless external and opaque AS LSA 0
Number of DoNotAge external and opaque AS LSA 0
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
External flood list length 0
Area 1
Number of interfaces in this area is 5
Area has no authentication
SPF algorithm executed 4 times
Area ranges are
Number of LSA 16. Checksum Sum 0x06b35e
Number of opaque link LSA 0. Checksum Sum 0x000000
Number of DCbitless LSA 0
Number of indication LSA 0
Number of DoNotAge LSA 0
Flood list length 0
1.0.0.30 0 FULL/ - 00:00:35 1.0.0.30 Serial0/1/1
1.0.0.5 0 FULL/ - 00:00:34 1.0.0.2 Serial0/1/0
Router#
04-29-2023 07:18 AM
Friend' if these subinterface is in area 1 then router that these subinterface is connect to must also connect to area 0 otherwise router never advertise lsa3 for these subinterface subnet to other router.
So either config all area same in all router
Or
Make subinterface in different area and make area interconnect routers area 0
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