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C93180YC-FX3 IPv6 neighbor discovery problems

7tsommer
Level 1
Level 1

‎12-21-2023 11:14 AM - edited ‎12-21-2023 11:19 AM

We're in the process of replacing a long list of Nexus C3064PQ chassis with C93180YC-FX3s. Many of those 3064s are paired together and have a crosslink configured for IPv4 and IPv6 for iBGP peering. For some reason, we cannot get IPv6 working (not even ping6) between the pairs once they've both been upgraded to 93180s. When we've upgraded one side, the new 93180 can get IPv6 adjacency with its 3064 peer and other devices. Once both chassis are upgraded, the 93180s can only get IPv6 adjacencies with other non-93180 devices. Running "debug ipv6 nd" shows that both sides are sending NSes on the crosslink interface, but neither side is receiving anything back. IPv4 pings, bgp peering, etc work fine on the same link.

We have tried everything under the sun to get this working. Here is the bare basic crosslink config that works with IPv4 but not with IPv6 unless one side isn't a 93180:

 

 

 

Router A:

interface Ethernet1/1
ip address 10.10.10.1/30
ipv6 address dead:beef::0/127
no shutdown



Router B:

interface Ethernet1/1
ip address 10.10.10.2/30
ipv6 address dead:beef::1/127
no shutdown

 

 

 

 

Any thoughts as to why the 93180s aren't playing nice with each other over IPv6? 

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2 Replies 2

Harold Ritter
Cisco Employee
Cisco Employee

‎12-22-2023 09:53 AM - edited ‎12-22-2023 10:03 AM

Hi @7tsommer ,

Can you provide the output for the following commands from both sides.

sh ipv6 int e1/1 detail

sh ipv6 neighbor detail

Could you also try pinging from one side to the other using the link local address rather than the configured IPv6 address.

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
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7tsommer
Level 1
Level 1
In response to Harold Ritter

‎12-22-2023 12:58 PM

Harold,

Here's the output you requested. Note that in the "show ipv6 neighbor detail" output there are working IPv6 neighbors (with their IPs obscured) on another port (Po1). Also note that in the output on both routers, our Eth1/1 showed up with the other side's link-local address but an all zeroes mac address. These entries continually pop up and disappear when reissuing the command. The address is always the other side's link-local and the mac address is always all zeroes.

Router A:

Router A# show run int e1/1

!Command: show running-config interface Ethernet1/1
!Running configuration last done at: Fri Dec 22 20:45:03 2023
!Time: Fri Dec 22 20:45:18 2023

version 9.3(8) Bios:version 01.06 

interface Ethernet1/1
  ip address 10.10.10.1/30
  ipv6 address dead:beef::/127
  no shutdown

Router A# 
Router A# 
Router A# 
Router A# 
Router A# ping 10.10.10.2
PING 10.10.10.2 (10.10.10.2): 56 data bytes
36 bytes from 10.10.10.1: Destination Host Unreachable
Request 0 timed out
64 bytes from 10.10.10.2: icmp_seq=1 ttl=254 time=0.742 ms
64 bytes from 10.10.10.2: icmp_seq=2 ttl=254 time=0.709 ms
64 bytes from 10.10.10.2: icmp_seq=3 ttl=254 time=0.539 ms
64 bytes from 10.10.10.2: icmp_seq=4 ttl=254 time=0.505 ms

--- 10.10.10.2 ping statistics ---
5 packets transmitted, 4 packets received, 20.00% packet loss
round-trip min/avg/max = 0.505/0.623/0.742 ms
Router A# 
Router A# 
Router A# 
Router A# 
Router A# ping6 dead:beef::1
PING6 dead:beef::1 (dead:beef::1): 56 data bytes
Request 0 timed out
Request 1 timed out
Request 2 timed out
Request 3 timed out
Request 4 timed out

--- dead:beef::1 ping6 statistics ---
5 packets transmitted, 0 packets received, 100.00% packet loss
Router A# 
Router A# 
Router A# 
Router A# 
Router A# show ipv6 int e1/1 detail
IPv6 Interface Status for VRF "default"(1)
Ethernet1/1, Interface status: protocol-up/link-up/admin-up, iod: 40
  IPv6 address: 
    dead:beef::/127 [VALID]
  IPv6 subnet:  dead:beef::/127
  IPv6 link-local address: fe80::c2f8:7fff:fe89:d767 (default) [VALID]
  IPv6 virtual addresses configured: none
  IPv6 multicast routing: disabled
  IPv6 report link local: disabled
  IPv6 Forwarding feature: disabled
  IPv6 multicast groups locally joined:   
      ff02::2  ff02::1  ff02::1:ff00:0  ff02::1:ff89:d767   
      ff02::1:ff00:0  
  IPv6 multicast (S,G) entries joined: none
  IPv6 MTU: 1500 (using link MTU)
  IPv6 unicast reverse path forwarding: none
  IPv6 load sharing: none 
  IPv6 interface statistics last reset: never
  IPv6 interface RP-traffic statistics: (forwarded/originated/consumed)
    Unicast packets:      0/0/0
    Unicast bytes:        0/0/0
    Multicast packets:    0/16/9
    Multicast bytes:      0/1424/712
  IPv6 interface counters/flags: 
Extended Stats:
Unspecified source        0
Total packet received on tentative address        6
Total Packet received on invalid address state        0
Total packet received on duplicate state        0
Anycast packet arrived on TCP        0
Deliver interface Down        0
Fragmented ND Packet Drops        0
Router A# 
Router A# 
Router A# 
Router A# 
Router A# ! ping link-local of other side
Router A# ping6 fe80::826a:ff:fe3f:f573
Interface: Ethernet1/1
PING6 fe80::826a:ff:fe3f:f573 (fe80::826a:ff:fe3f:f573): 56 data bytes
Request 0 timed out
Request 1 timed out
Request 2 timed out
Request 3 timed out
Request 4 timed out

--- fe80::826a:ff:fe3f:f573 ping6 statistics ---
5 packets transmitted, 0 packets received, 100.00% packet loss
Router A# 
Router A# 
Router A# 
Router A# 
Router A# show ipv6 neighbor det
No. of Adjacency hit with type INVALID: Packet count 0, Byte count 0
No. of Adjacency hit with type GLOBAL DROP: Packet count 0, Byte count 0
No. of Adjacency hit with type GLOBAL PUNT: Packet count 0, Byte count 0
No. of Adjacency hit with type GLOBAL GLEAN: Packet count 0, Byte count 0
No. of Adjacency hit with type GLEAN: Packet count 0, Byte count 0
No. of Adjacency hit with type NORMAL: Packet count 0, Byte count 0

Adjacency statistics last updated before: never

IPv6 Adjacency Table for VRF default
Total number of entries: 1

Address :            fe80::826a:ff:fe3f:f573
Age :                00:00:02
MacAddr :            0000.0000.0000
Preference :         255 
Source :             icmpv6         
Interface :          Ethernet1/1        
Physical Interface : Ethernet1/1
Packet Count :       0   
Byte Count :         0   
Best :               Yes
Throttled :           No

Address :            xxxx:xxxx::xxxx
Age :                00:11:55
MacAddr :            1859.f58f.b1f7
Preference :         50  
Source :             icmpv6         
Interface :          port-channel1   
Physical Interface : Ethernet1/3      
Packet Count :       0   
Byte Count :         0   
Best :               Yes
Throttled :           No

 

Router B:

Router B# show run int e1/1

!Command: show running-config interface Ethernet1/1
!Running configuration last done at: Fri Dec 22 20:47:01 2023
!Time: Fri Dec 22 20:48:01 2023

version 9.3(8) Bios:version 01.06 

interface Ethernet1/1
  ip address 10.10.10.2/30
  ipv6 address dead:beef::1/127
  no shutdown

Router B# 
Router B# 
Router B# 
Router B# 
Router B# ping 10.10.10.1
PING 10.10.10.1 (10.10.10.1): 56 data bytes
64 bytes from 10.10.10.1: icmp_seq=0 ttl=254 time=0.78 ms
64 bytes from 10.10.10.1: icmp_seq=1 ttl=254 time=0.564 ms
64 bytes from 10.10.10.1: icmp_seq=2 ttl=254 time=0.456 ms
64 bytes from 10.10.10.1: icmp_seq=3 ttl=254 time=0.522 ms
64 bytes from 10.10.10.1: icmp_seq=4 ttl=254 time=0.523 ms

--- 10.10.10.1 ping statistics ---
5 packets transmitted, 5 packets received, 0.00% packet loss
round-trip min/avg/max = 0.456/0.569/0.78 ms
Router B# 
Router B# 
Router B# 
Router B# 
Router B# ping6 dead:beef::
PING6 dead:beef:: (dead:beef::): 56 data bytes
Request 0 timed out
Request 1 timed out
Request 2 timed out
Request 3 timed out
Request 4 timed out

--- dead:beef:: ping6 statistics ---
5 packets transmitted, 0 packets received, 100.00% packet loss
Router B# 
Router B# 
Router B# 
Router B# 
Router B# show ipv6 int e1/1 detail
IPv6 Interface Status for VRF "default"(1)
Ethernet1/1, Interface status: protocol-up/link-up/admin-up, iod: 46
  IPv6 address: 
    dead:beef::1/127 [VALID]
  IPv6 subnet:  dead:beef::/127
  IPv6 link-local address: fe80::826a:ff:fe3f:f573 (default) [VALID]
  IPv6 virtual addresses configured: none
  IPv6 multicast routing: disabled
  IPv6 report link local: disabled
  IPv6 Forwarding feature: disabled
  IPv6 multicast groups locally joined:   
      ff02::2  ff02::1  ff02::1:ff00:1  ff02::1:ff3f:f573   
      ff02::1:ff00:0  
  IPv6 multicast (S,G) entries joined: none
  IPv6 MTU: 1500 (using link MTU)
  IPv6 unicast reverse path forwarding: none
  IPv6 load sharing: none 
  IPv6 interface statistics last reset: never
  IPv6 interface RP-traffic statistics: (forwarded/originated/consumed)
    Unicast packets:      0/0/0
    Unicast bytes:        0/0/0
    Multicast packets:    0/16/9
    Multicast bytes:      0/1424/712
  IPv6 interface counters/flags: 
Extended Stats:
Unspecified source        0
Total packet received on tentative address        0
Total Packet received on invalid address state        0
Total packet received on duplicate state        0
Anycast packet arrived on TCP        0
Deliver interface Down        0
Fragmented ND Packet Drops        0
Router B# 
Router B# 
Router B# 
Router B# 
Router B# ! ping link-local of other side
Router B# ping6 fe80::c2f8:7fff:fe89:d767
Interface: Ethernet1/1
PING6 fe80::c2f8:7fff:fe89:d767 (fe80::c2f8:7fff:fe89:d767): 56 data bytes
Request 0 timed out
Request 1 timed out
Request 2 timed out
Request 3 timed out
Request 4 timed out

--- fe80::c2f8:7fff:fe89:d767 ping6 statistics ---
5 packets transmitted, 0 packets received, 100.00% packet loss
Router B# 
Router B# 
Router B# 
Router B# 
Router B# show ipv6 neighbor detail
No. of Adjacency hit with type INVALID: Packet count 0, Byte count 0
No. of Adjacency hit with type GLOBAL DROP: Packet count 0, Byte count 0
No. of Adjacency hit with type GLOBAL PUNT: Packet count 0, Byte count 0
No. of Adjacency hit with type GLOBAL GLEAN: Packet count 0, Byte count 0
No. of Adjacency hit with type GLEAN: Packet count 0, Byte count 0
No. of Adjacency hit with type NORMAL: Packet count 0, Byte count 0

Adjacency statistics last updated before: never

IPv6 Adjacency Table for VRF default
Total number of entries: 2

Address :            fe80::c2f8:7fff:fe89:d767
Age :                00:00:02
MacAddr :            0000.0000.0000
Preference :         255 
Source :             icmpv6         
Interface :          Ethernet1/1        
Physical Interface : Ethernet1/1
Packet Count :       0   
Byte Count :         0   
Best :               Yes
Throttled :           No

Address :            xxxx:xxxx::xxxx
Age :                00:08:35
MacAddr :            cced.4ddb.780b
Preference :         50  
Source :             icmpv6         
Interface :          port-channel1   
Physical Interface : Ethernet1/3      
Packet Count :       0   
Byte Count :         0   
Best :               Yes
Throttled :           No
Router B#
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