OSPF Routes

[abarb002]

I have a LAN set up consisting of one Layer 3 SW and 5 Layer 2 switches. All is well and working fine, but on the layer 3 sw when I enter the "sh ip route" command I don't seen any OSPF routes in the routing table. All switches are connected via a vlan interface and OSPF is my routing protocol. When I enter show the "ip osp neighbor" command, all devices are present and I have connectivity. I have pcs connected to the layer 2 switches and can ping or ssh (Linux and Win) to each box on the network. All the ips are present in the ARP table on the layer 3 switch. My issue is that I cannot see OSPF routes in the layer 3 device, but can see them on the layer 2 devices. Is this a problem? 

[balaji.bandi]

one Layer 3 SW and 5 Layer 2 switches  - when you say 1 Layer 3 device, you do not need any OSPF here.

How is your Layer 2 switch connected to Layer 3 switch, is this Layer 2 Trunk or Layer 3 Point to Point interface config ?

can you post Layer 3 and Laye 2 swich config, and also post show ip ospf neigh

[abarb002]

they are connected physically through a trunk port. I'm on a restricted network and therefore can't post configs. I checked my OPSF int and they all seem to be set to broadcast. 

[balaji.bandi]

how about on the Layer 2 Switch, do you see show ip router ospf ? and you can check OSPF Database.

[Giuseppe Larosa · Accepted solution]

Hello @abarb002 ,

the L3 device sees all subnets as connected this is why show ip route ospf  is empty on it.

This also explains why you have ARP entries for all hosts in the network.

Other devices may be able to see OSPF routes for the simple reason that they have a single SVI so all other subnets are learned via OSPF from the central L3 switch.

I would say it is normal what you see.

You can check the OSPF database with

show ip ospf database

show ip ospf databse detail

You will see all subnets even if they are direclty connected listed in the router LSA of the central switch

Hope to help

Giuseppe

[abarb002]

You were correct. I wasn't 100 percent sure, but I wanted to reach out to make sure all was well. I connected my laptop to one of the interfaces on the layer 3 and was able to establish a connection to other devices on the network on the said vlan. Thanks for your help. 

[MHM Cisco World]

if you use single SVI in all SW then it OK 
if not then there is problem