Hi,
I have configured my ASR9k routers with ipv6 addresses and vrrp feature. But there comes immediately duplicate address detection, if I configure any address:
Thu Sep 27 08:35:39.140 CEST
Building configuration...
!! IOS XR Configuration 6.1.4
interface BVI804
+ ipv6 address 1234:5678:2200::50/48
!
end
RP/0/RSP0/CPU0:R1(config-if)#commit
Thu Sep 27 08:35:41.026 CEST
LC/0/0/CPU0:Sep 27 08:35:41.072 : ipv6_nd[258]: %IP-IPV6_ND-3-ADDRESS_DUPLICATE : Duplicate address 1234:5678:2200::50 has been detected on BVI804
Additionaly I can say, that my vrrp configuration for this interface has been configured as follows:
RP/0/RSP0/CPU0:R1#sh run router vrrp
Thu Sep 27 08:44:26.987 CEST
router vrrp
(...)
interface BVI804
address-family ipv4
(...)
!
!
address-family ipv6
vrrp 84
priority 150
address global 1234:5678:2200::1
address linklocal fe80::7aba:f9ff:fe43:804
!
!
!
And now...
If I only set on my interface any address, by changing any of last 8 bits, DAD says there is a duplicate address:
RP/0/RSP0/CPU0:R1(config-if)#show commit ch d
Thu Sep 27 08:36:04.651 CEST
Building configuration...
!! IOS XR Configuration 6.1.4
interface BVI804
- ipv6 address 1234:5678:2200::50/48
+ ipv6 address 1234:5678:2200::ff/48
!
end
RP/0/RSP0/CPU0:R1(config-if)#commit
Thu Sep 27 08:36:07.167 CEST
LC/0/0/CPU0:Sep 27 08:36:07.214 : ipv6_nd[258]: %IP-IPV6_ND-3-ADDRESS_DUPLICATE : Duplicate address 1234:5678:2200::ff has been detected on BVI804
but if I go behind last 8 bits with changes, duplicate address is not more any issue:
Thu Sep 27 08:36:54.246 CEST
Building configuration...
!! IOS XR Configuration 6.1.4
interface BVI804
- ipv6 address 1234:5678:2200::ff/48
+ ipv6 address 1234:5678:2200::100/48
!
end
RP/0/RSP0/CPU0:R1(config-if)#commit
Thu Sep 27 08:36:56.100 CEST
RP/0/RSP0/CPU0:Sep 27 08:36:56.328 : config[65935]: %MGBL-CONFIG-6-DB_COMMIT : Configuration committed by user 'user'. Use 'show configuration commit changes 1000000488' to view the changes.
RP/0/RSP0/CPU0:R1#sh ipv6 int bvi804
Thu Sep 27 08:42:57.803 CEST
BVI804 is Up, ipv6 protocol is Up, Vrfid is default (0x60000000)
IPv6 is enabled, link-local address is fe80::7aba:f9ff:fe4d:6b2d
Global unicast address(es):
1234:5678:2200::100, subnet is 1234:5678:2200::/48
Joined group address(es): ff02::1:ff00:100 ff02::1:ff4d:6b2d ff02::2
ff02::1 ff02::12
MTU is 1514 (1500 is available to IPv6)
ICMP redirects are disabled
ICMP unreachables are enabled
ND DAD is enabled, number of DAD attempts 1
ND reachable time is 0 milliseconds
ND cache entry limit is 1000000000
ND advertised retransmit interval is 0 milliseconds
ND router advertisements are sent every 30 to 60 seconds
ND router advertisements live for 900 seconds
Hosts use DHCP to obtain routable addresses.
Outgoing access list is not set
Inbound common access list is not set, access list is not set
Table Id is 0xe0800000
Complete protocol adjacency: 0
Complete glean adjacency: 0
Incomplete protocol adjacency: 0
Incomplete glean adjacency: 0
Dropped protocol request: 0
Dropped glean request: 0
RP/0/RSP0/CPU0:R1#
Why is it so, especially, that on the same pair of routers, on different interfaces, but the same logic of addressing, this issue does not appear?
