Multilayer Switch VLAN, OSPF communication problem

[stsyrn]

 Hello, I am trying to ping PC4 with PC0 but I can't. What should I do?
In this network, I have to simulate 2 devices as a single device because the ports are not enough. Also, I need to connect switches to each other with OSPF. That's why Multi switches are connected to each other with OSPF.
PC0, PC1, and PC4 in VLAN2, PC2, and PC3 in VLAN3.
Multilayer Switches are connected to each other via gig 1/0/1.

Multilayer Switch0 Config

PC0-- Gig 1/0/2      PC1-- Gig 1/0/3

PC2--Gig 1/0/4      PC3-- Gig 1/0/5

no ip cef
ip routing
!
no ipv6 cef
!
no ip domain-lookup
!
spanning-tree mode pvst
!
!
interface GigabitEthernet1/0/1
 no switchport
 ip address 10.100.0.1 255.255.255.0
 duplex auto
 speed auto
!
interface GigabitEthernet1/0/2
 switchport access vlan 2
 switchport mode access
 switchport nonegotiate
!
interface GigabitEthernet1/0/3
 switchport access vlan 2
 switchport mode access
 switchport nonegotiate
!
interface GigabitEthernet1/0/4
 switchport access vlan 3
 switchport mode access
 switchport nonegotiate
!
interface GigabitEthernet1/0/5
 switchport access vlan 3
 switchport mode access
 switchport nonegotiate

!
interface Vlan1
 no ip address
 shutdown
!
interface Vlan2
 mac-address 00e0.f7ad.7201
 ip address 10.10.10.100 255.255.255.0
!
interface Vlan3
 mac-address 00e0.f7ad.7202
 ip address 20.20.20.100 255.255.255.0
!
router ospf 2
 router-id 10.100.0.1
 log-adjacency-changes
 network 10.100.0.0 0.0.0.255 area 0
 network 20.20.20.0 0.0.0.255 area 0
 network 10.10.10.0 0.0.0.255 area 0
!
ip classless
!
ip flow-export version 9
!
!
!
!
line con 0
!
line aux 0
!
line vty 0 4
 login
!
!
end

Multilayer Switch1 Config

PC4-- Gig 1/0/2 in Multilayer Switch 1

!
no ip cef
ip routing
!
no ipv6 cef
!
!
!
spanning-tree mode pvst
!
!
!
interface GigabitEthernet1/0/1
 no switchport
 ip address 10.100.0.2 255.255.255.0
 duplex auto
 speed auto
!
interface GigabitEthernet1/0/2
 switchport access vlan 2
 switchport mode access
 switchport nonegotiate
!

interface Vlan1
 no ip address
 shutdown
!
interface Vlan2
 mac-address 000a.f371.a001
 ip address 10.10.10.100 255.255.255.0
!
router ospf 2
 router-id 10.100.0.2
 log-adjacency-changes
 network 20.20.20.0 0.0.0.255 area 0
 network 10.100.0.0 0.0.0.255 area 0
 network 10.10.10.0 0.0.0.255 area 0
!
ip classless
!
ip flow-export version 9
!
!
line con 0
!
line aux 0
!
line vty 0 4
 login
!

!
end

[Ariyarathna · Accepted solution]

Hi @stsyrn  PC4 can not be in PC0 &PC1 subnet . Because they are separated by  L3 network (with L3 Switches) and therefore can not be resided in same LAN. Therefore you must change IP subnet of one of those networks .

Thanks,

Manoj

[balaji.bandi]

If you are not extended the VLAN to other switch iot may not work, or you need to use different IP address in the Local segment to communiucated with otehr Layer 3 network.

[Richard Burts]

To expand a bit on the explanation by Manoj, which does correctly identify the issue as problems when you attempt to have the same IP subnet in 2 different parts of the network and connected by some other subnet. The issue is that switch 1 OSPF will advertise subnet 10.10.10.0/24 to switch 0 OSPF. But switch 0 already has a route for 10.10.10.0/24 as a locally connected subnet. The Administrative Distance for locally connected is better than the AD for the OSPF route and switch 0 will not implement the subnet on switch 1.

[stsyrn]

Thank you everyone for your answers. I tried a different subnet in PC4 and I did. Also, I will try ethercannel+hsrp for communication of switches.

[Richard Burts]

You are welcome. I am glad that our suggestions and explanations have been helpful.