Re: OSPFv3 Neighbor Adjacencies problem

se.dejbjerg · ‎02-01-2019

Hi,

In a setup with a router 2901 and a L3 Switch C3750G (take a look at the image) both setup with OSPFv3 and assigned with both global unicast and link local addr. I can ping from the router to the switch and vice versa.

Debugging hello packets show that the router sends and receive hello packet from the switch, but the switch only sends hello packets, but don't receive any from the router.

Hope someone can help with the missing hello packets from the router to the switch.

Regards

sd

Netlabbuilder · ‎02-02-2019

It would be helpful if we have the debug output on the L3 switch and the relevant configuration of both devices.

se.dejbjerg · ‎02-03-2019

Hello hungtx_it

The debug info from from the L3 switch is shown just above the switch, and debug from the router is shown below the router, both switch and router are time synchronized with NTP.

Attached are OSPFv3 info from both switch and router.

Regards

sd

Sergey Lisitsin · ‎02-04-2019

se.dejbjerg,

Can you please show output of "show ipv6 interface brief" and "show ospfv3 interface brief" from both devices.

se.dejbjerg · ‎02-04-2019

Hi Sergey,

Here are the requested show output, notice that the L3 switch is a c3750 running ios v 12.2 so instead of "show ospfv3 interface brief" the command "show ipv6 ospf interface brief" command is used.

R1#sh ipv int bri
Em0/0                  [administratively down/down]
    unassigned
GigabitEthernet0/0     [up/up]
    FE80::3A0E:4DFF:FE7C:F8A0
    2AYY:XXXX:0:3::2
GigabitEthernet0/1     [up/up]
    FE80::1
    2AYY:XXXX:2::1

R1#sh ospfv3 int bri
Interface    PID   Area            AF         Cost State Nbrs F/C
Gi0/1        10    0               ipv6       1     DR    0/1
R1#

R1#sh ipv ospf int bri
Interface    PID   Area            Intf ID    Cost State Nbrs F/C
Gi0/1        10    0               4          1     DR    0/1

S1#sh ipv int bri
Vlan1                      [up/down]
    unassigned
Vlan12                     [up/up]
    FE80::1
    2AYY:XXXX:2:C::1
Vlan20                     [up/up]
    FE80::1
    2AYY:XXXX:2:14::1
Vlan980                    [up/up]
    FE80::101
    2AYY:XXXX:2::101
GigabitEthernet1/0/1       [down/down]
    unassigned
GigabitEthernet1/0/2       [up/up]
    unassigned

S1#sh ospfv3 int bri
               ^
% Invalid input detected at '^' marker.

S1#sh ipv ospf int bri
Interface    PID   Area            Intf ID    Cost State Nbrs F/C
Vl20         10    0               2088       1     DR    0/0
Vl12         10    0               2080       1     DR    0/0
Vl980        10    0               3048       1     DR    0/0

S1#

Regards,

se.dejbjerg

Sergey Lisitsin · ‎02-05-2019

OK, thanks. Can you please also show the following output from S1:

show span vlan 980

and from both:

show ipv6 neighbor

se.dejbjerg · ‎02-05-2019

Hi Sergey,

Here you have the requested info. For your info, all the STALE States change to REACH after a ping.

S1#sh span vla 980

VLAN0980
Spanning tree enabled protocol ieee
Root ID    Priority    33748
             Address     0013.1962.4a00
             Cost        12
             Port        28 (GigabitEthernet1/0/28)
             Hello Time   2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority    33748 (priority 32768 sys-id-ext 980)
             Address     64d9.8981.8280
             Hello Time   2 sec Max Age 20 sec Forward Delay 15 sec
             Aging Time 300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/2             Desg FWD 4         128.2    P2p
Gi1/0/15            Desg FWD 4         128.15   P2p
Gi1/0/16            Desg FWD 4         128.16   P2p
Gi1/0/17            Desg FWD 4         128.17   P2p
Gi1/0/18            Desg FWD 4         128.18   P2p
Gi1/0/24            Desg FWD 4         128.24   P2p
Gi1/0/28            Root FWD 4         128.28   P2p

S1#sh ipv nei
IPv6 Address                              Age Link-layer Addr State Interface
FE80::1                                     2 380e.4d7c.f8a1 STALE Vl980
2AYY:XXXX:2::1                              1 380e.4d7c.f8a1 STALE Vl980
FE80::20C:29FF:FEB1:582D                    7 000c.29b1.582d STALE Vl12
2AYY:XXXX:2:C:20C:29FF:FEB1:582D            7 000c.29b1.582d STALE Vl12

S-21-25-01#sh ipv nei

R1#sh span vla 980

Spanning tree instance for VLAN 980 does not exist.

R1#sh ipv nei
IPv6 Address                              Age Link-layer Addr State Interface
2AYY:XXXX:0:3::1                           15 8071.1f4a.b94a STALE Gi0/0
FE80::8271:1F08:D74A:B94A                  14 8071.1f4a.b94a STALE Gi0/0
2AYY:XXXX:2::101                            3 64d9.8981.82ce STALE Gi0/1
FE80::101                                   4 64d9.8981.82ce STALE Gi0/1

R1#

Sergey Lisitsin · ‎02-06-2019

All looks to be in order there. I would try to disable MLDP snooping on the switch and see if that helps.

Harold Ritter · ‎02-06-2019

Hi,

Sergey has a point. It might indeed be MLD snooping related. Can you try pinging FF02::5 from both sides.

Regards,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

se.dejbjerg · ‎02-07-2019

Hi Sergey and Harold,

Below you see the ping result of S1 to R1 and vice versa.

I can ping from the L3 switch to the router but not from the router to the L3 switch, that also matches with the fact that the router receives hello packets from the L3 switch but not vice versa.

S1#ping ff02::5
Output Interface: vla 980
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to FF02::5, timeout is 2 seconds:
Packet sent with a source address of FE80::101%Vlan980

Reply to request 0 received from FE80::1, 0 ms
Reply to request 1 received from FE80::1, 0 ms
Reply to request 2 received from FE80::1, 0 ms
Reply to request 3 received from FE80::1, 0 ms
Reply to request 4 received from FE80::1, 0 ms
Success rate is 100 percent (5/5), round-trip min/avg/max = 0/0/0 ms
5 multicast replies and 0 errors.
S1#

R1#ping ff02::5
Output Interface: gigabitethernet0/1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to FF02::5, timeout is 2 seconds:
Packet sent with a source address of FE80::1%GigabitEthernet0/1

Request 0 timed out
Request 1 timed out
Request 2 timed out
Request 3 timed out
Request 4 timed out
Success rate is 0 percent (0/5)
0 multicast replies and 0 errors.
R1#

Regards

se.dejbjerg

Harold Ritter · ‎02-07-2019

Have you tried disabling MLD snooping on the L3 switch, as suggested by Sergey?

Regards,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

se.dejbjerg · ‎02-07-2019

Hi Harold

Just tried to disable MLD snooping on the L3 switch with the global config command "no ipv6 mld snooping" and to be sure "no ipv6 mld snooping vlan 980". But still no successful ping with ff02::5 from R1, and the L3 switch only sending hello packets.

Tomorrow I am planning on attaching a similar L3 switch to the vlan 980 and see how it will act with the existing L3 switch and the router, all three devices at the same time and two devices at a time.

Regards

se.dejbjerg

Harold Ritter · ‎02-07-2019

Can you please post the following output:

R1:

show ipv6 int GigabitEthernet0/1

S1:

show ipv6 int Vlan980

Regards,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

se.dejbjerg · ‎02-07-2019

Hi Harold,

Here you have the requested output:

R1#sh ipv int g0/1
GigabitEthernet0/1 is up, line protocol is up
IPv6 is enabled, link-local address is FE80::1
No Virtual link-local address(es):
Description: LAN
Global unicast address(es):
    2AYY:XXXX:2::1, subnet is 2AYY:XXXX:2::/64
Joined group address(es):
    FF02::1
    FF02::2
    FF02::5
    FF02::6
    FF02::1:FF00:1
MTU is 1500 bytes
ICMP error messages limited to one every 100 milliseconds
ICMP redirects are enabled
ICMP unreachables are sent
Input features: Common Flow Table Stile classification
Output features: Common Flow Table Stile Classification
ND DAD is enabled, number of DAD attempts: 1
ND reachable time is 30000 milliseconds (using 30000)
ND advertised reachable time is 0 (unspecified)
ND advertised retransmit interval is 0 (unspecified)
ND router advertisements are sent every 200 seconds
ND router advertisements live for 1800 seconds
ND advertised default router preference is Medium
Hosts use stateless autoconfig for addresses.
R1#

S1#sh ipv int vla 980
Vlan980 is up, line protocol is up
IPv6 is enabled, link-local address is FE80::101
No Virtual link-local address(es):
Description: LAN_to_Router
Global unicast address(es):
    2AYY:XXXX:2::101, subnet is 2AYY:XXXX:2::/64
Joined group address(es):
    FF02::1
    FF02::2
    FF02::5
    FF02::6
    FF02::1:FF00:101
MTU is 1500 bytes
ICMP error messages limited to one every 100 milliseconds
ICMP redirects are enabled
ICMP unreachables are sent
Output features: Check hwidb
ND DAD is enabled, number of DAD attempts: 1
ND reachable time is 30000 milliseconds (using 30000)
ND advertised reachable time is 0 (unspecified)
ND advertised retransmit interval is 0 (unspecified)
ND router advertisements are sent every 200 seconds
ND router advertisements live for 1800 seconds
ND advertised default router preference is Medium
Hosts use stateless autoconfig for addresses.
S1#

Regards,

se.dejbjerg

gnc50 · ‎04-18-2019

both switch and router are time synchronized with NTP.

Attached are OSPFv3 info from both switch and router https://audacity.onl/ https://findmyiphone.onl/ https://origin.onl/