Can an SVI exist on two layer 3 switches?; Different IPs same subnet.

[BruteForce]

I have this collapsed core thing going on with two layer 3 switches (A and B), and they have two Access switches below them (1 and 2). 

A and B have a /31 point-to-point connection between them, and the ports have "ip ospf 1 area 0" configured onto them. The connection is good and I can ping.

1 and 2, the purely layer 2 switches, each have one connection to switch A and B. Their trunks have Vlan 50, a management vlan, configured onto them. 

Switch A hosts vlan 50:                       IP 10.0.0.1 /24. "ip ospf 1 area 0" is configured on this SVI.
Switch 1 has a management vlan with IP 10.0.0.3 /24
Switch 2 has a management vlan with IP 10.0.0.4 /24

All three of these switches can ping each other. But when I configure 10.0.0.2 /24 on Switch B, nothing can ping it, even with "ip ospf 1 area 0". If I configure an Loopback0 on Switch B, Switch A can ping that Loopback address.

If I "debug ip routing" on Switch A and add a Loopback0 to Switch B, I get a notification that the network is learned. If I add 10.0.0.2/24 on Switch B, there are no updates according to "debug ip routing" on Switch A.  I am also not using HSRP in any way.

Why is this not working? I'm just doing a lab for learning purposes and can't figure out why Switch B won't work with this IP/Subnet. Is it likely that I'm configuring something wrong, or is this not meant to work? The lab is on CML. 

[MHM Cisco World]

Can you share your topolgy with note on it

Thanks 

MHM

[MHM Cisco World]

In network there is physical and logical link'

As I get you have vlan across three SW and you run ospf between three SW

If yes ' the  you need to add SVI to all SW to participate in ospf.

Note:- you mention that two of sw also have p2p that not effect ospf but it will show you two path one via svi and other via p2p.

Note:- add link between all three sw access or trunk allow vlan.

MHM

[pieterh]

if your info is correct, then this has nothing to do with ospf routing!
10.0.0.1, 10.0.0.2 and 10.0.0.3 are all addresses in a single subnet 10.0.0.0/24
so each host in vlan 50 should be able to reach other hosts in vlan 50 subnet 10.0.0.0/24 directly without routing involved

[balaji.bandi]

If the Switch A and B are in Layer 3 connected, does the network 10.0.0.0/24 network announced in the network ?

Switch 1 and 2 connect to A and B - do you have any default route configured ?

Does Switch A and B is the SVI vlan 50 come up ? (post from all switches)

#show ip interface brief

# show ip route

# show vlan

# show spanning (information)

(still issue, post show run also from all devices)

[paul driver]

Hello

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@BruteForce wrote:
 But when I configure 10.0.0.2 /24 on Switch B nothing can ping it, even with "ip ospf 1 area 0". If I configure an Loopback0 on Switch B, Switch A can ping that Loopback address.

1 and 2, the purely layer 2 switches

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So if the switch is purely L2 then no ip routing should be enabled (no ip routing) , However if you need to make them L3 switches then you need to enable ip routing, (ip routing) and if you do this you need some way to advertise your networks either statically or via a dynamic routing process such as OSPF which requires ospf adjacencies to form between routing devices such as these L3 switches.

If 10.0.0.0/24  is a SVI then you need to create its L2 vlan equivalent and make sure the SVI is in a up/up state.
Lasty when you enable ip routing on a switch then any configured default-gateway statement becomes invalid and you would require a default route instead to provide access any external network UNELSS that is you are receiving a default via OSPF or all the networks that you need to reach are being advertised and received over OSPF into Switch2

Example: Switch2
ip routing
router ospf 1
router-id x.x.x.x

int vlan Y
ip address 10.0.0.x 255.255.255.0
ip ospf 1 area 0
no shut

vlan Y
exit
ip route 0.0.0.0 0.0.0.0 vlan Y x.x.x.x (next-hop ip)

sh ip int brief | in up
sh int vlan Y