![]() ![]() Suppress hello for 0 neighbor(s) Reason 2: Wrong Address Assignment in Dual Serial Link SetupĬonsider this network diagram as an example: Process ID 20, Router ID 172.16.33.1, Network Type POINT_TO_POINT, Cost: 64 R4-4K(4)(config-if)# no ip ospf network broadcast In this example we have removed the network-type broadcast statement on R4-4K because both sides are point-to-point High-Level Data Link Control (HDLC) encapsulated interfaces. Note: If you have a situation where one side is a multipoint interface and the other side is a sub-interface then change the network type to broadcast on both sides. You can either change the network type of Router R1-7010 to broadcast, or change Router R4-4K serial interface to point-to-point. To solve this problem, configure both routers for the same network type. This creates a discrepancy in the link-state database, which means no routes are installed in the routing table. You can see that for subnet 172.16.32.0/24, Router R1-7010 generates a point-to-point link and Router R4-4K generates a transit link. (Link Data) Router Interface address: 172.16.32.1 (Link ID) Designated Router address: 172.16.32.1 R1-7010(5)# show ip ospf database router 172.16.33.1 Adv Router is not-reachable (Link Data) Router Interface address: 172.16.32.2 (Link ID) Neighboring Router ID: 172.16.33.1 Link connected to: another Router (point-to-point) ![]() R4-4K(4)# show ip ospf database router 172.16.32.2 Adv Router is not-reachable This kind of network type mismatch makes the advertising router unreachable. Transmit Delay is 1 sec, State POINT_TO_POINT,Īs you can see in the previous output, Router R4-4K is configured for broadcast, and Router R1-7010 is configured for point-to-point. Process ID 20, Router ID 172.16.32.2, Network Type POINT_TO_POINT, Cost: 64 R1-7010(5)# show ip ospf interface serial 1/0 Neighbor Count is 1, Adjacent neighbor count is 1Īdjacent with neighbor 172.16.32.2 (Backup Designated Router) Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Process ID 20, Router ID 172.16.33.1, Network Type BROADCAST, Cost: 64 R4-4K(4)# show ip ospf interface serial 2 The next network diagram is used as an example: If you have the output of any of these commands from your Cisco device, you can use Cisco CLI Analyzer to display potential issues and fixes. Some of the commands used throughout this document for verification of OSPF behavior include the show ip ospf interface, show ip ospf database router, show ip ospf neighbor and the show ip ospf database external. This document explains some of the more common reasons that can cause the discrepancy in the database. When the configuration is corrected the OSPF database discrepancy goes away and the routes appear in the routing table. There are several reasons for this problem, most of which deal with mis-configuration or a broken topology. Here is an example: Router# show ip ospf database router 172.16.32.2 Often, you can see the Adv Router is not-reachable message (which means the router that advertises the LSA is not reachable through OSPF) on top of the link-state advertisement (LSA) in the database when this problem occurs. In most cases OSPF finds a discrepancy in the database so it does not install the route in the routing table. This document describes a common problem with tOpen Shortest Path First (OSPF) in which the routes that are in the database do not appear in the Routing Information Base (RIB) or routing table. Conventionsįor more information on document conventions, see the Cisco Technical Tips Conventions. If your network is live, ensure that you understand the potential impact of any command. All of the devices used in this document started with a cleared (default) configuration. The information in this document was created from the devices in a specific lab environment. ![]() This is supported on all Cisco router platforms The information in this document is based on these software and hardware versions:Ĭisco IOS ® Software Release 12 and later Readers of this document must have knowledge of these topics:īasic knowledge of OSPF configuration in Cisco IOS ® This document describes how to repair a problem with Open Shortest Path First (OSPF) when routes in the database are not in the Routing Information Base (RIB) or routing table.
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