Why can't L3 switch build ipv6 routing table via ospf ?

[nmmn1359]

Multilayer Switch66 can build ipv4 routing table via ospf.

```

20.0.0.0/24 is subnetted, 1 subnets

C 20.20.20.0 is directly connected, Vlan10

O IA 192.168.30.0/24 [110/2] via 20.20.20.29, 00:38:20, Vlan10

[110/2] via 20.20.20.69, 00:38:20, Vlan10

```

Why can't it build 1111::/64 table via ospf ?

```

C 2222::/64 [0/0]

via ::, Vlan10

L 2222::7777/128 [0/0]

via ::, Vlan10

L FF00::/8 [0/0]

via ::, Null0

```

Switch66 running config

ip cef

ip routing

ipv6 unicast-routing

ipv6 cef

!

interface GigabitEthernet1/0/1

switchport access vlan 10

!

interface GigabitEthernet1/0/2

switchport access vlan 10

!

interface Vlan10

ip address 20.20.20.66 255.255.255.0

ipv6 address 2222::7777/64

ipv6 ospf 1 area 0.0.0.0

!

router ospf 1

router-id 66.66.66.66

log-adjacency-changes

network 20.20.20.0 0.0.0.255 area 0.0.0.0

!

ipv6 router ospf 1

router-id 66.66.66.66

log-adjacency-changes

area 0.0.0.0 range 2222::/64

Switch69 running config

ip cef

ip routing

ipv6 unicast-routing

ipv6 cef

!

interface GigabitEthernet1/0/1

switchport access vlan 30

!

interface GigabitEthernet1/0/2

switchport access vlan 10

!

interface Vlan10

ip address 20.20.20.69 255.255.255.0

ipv6 address 2222::8888/64

ipv6 ospf 1 area 0.0.0.0

!

interface Vlan30

ip address 192.168.30.69 255.255.255.0

ipv6 address 1111::8888/64

ipv6 ospf 1 area 192.168.30.0

standby version 2

!

router ospf 1

router-id 69.69.69.69

log-adjacency-changes

network 192.168.30.0 0.0.0.255 area 192.168.30.0

network 20.20.20.0 0.0.0.255 area 0.0.0.0

!

ipv6 router ospf 1

router-id 69.69.69.69

log-adjacency-changes

area 0.0.0.0 range 2222::/64

area 192.168.30.0 range 1111::/64

Switch29 has the similar running config with Switch69 but with different ip address and Switch73 acts as a layer 2 switch. The topo shows below.

[Giuseppe Larosa]

Hello @nmmn1359 ,

check on switch66 if the OSPFv3 adjacency with switch69 is built using

show ipv6 ospf neighbors

This is the first step on troubleshooting.

Hope to help

Giuseppe

[nmmn1359]

This command shows nothing. What configurations do I miss ?

[Giuseppe Larosa]

Hello @nmmn1359 ,

switch66 : vlan 10: ipv6 address: ipv6 address 2222::7777/64

and

switch69: vlan 10 :  ipv6 address 2222::8888/64

are in the same /64 IPv6 subnet or are they are in two different IPv6 subnets ?

for me they are in two different IPv6 subnets.

read the following document

https://www.cisco.com/c/en/us/support/docs/ip/ip-version-6-ipv6/112100-ospfv3-config-guide.html?dtid=osscdc000283

look at the configuration of ipv6 address both routers have the following:

ipv6 address FD01:ABAB::/64 eui-64

add eui-64 on your configuration of ipv6 addresses.

OSPFv3 can build adjacency on link local addresses FE80 ...

Hope to help

Giuseppe

[Harold Ritter]

Hi @nmmn1359 ,

I think this is due to a Cisco Packet Tracer limitation. Try applying the IPv6 configuration directly on the physical instead of the vlan interface and the ipv6 ospf adjacency should come up.

Switch69:

no interface Vlan10

interface GigabitEthernet1/0/2

no switchport

ip address 20.20.20.69 255.255.255.0

ipv6 address 2222::8888/64

ipv6 ospf 1 area 0.0.0.0

Do the same on Switch66 and the session should come up.

Regards,