IPv6 Neighbor Discovery cache resiliency to IPv6 unicast addresses getting recycled

gistfile1.txt

Here is a trace showing that the IPv6 Neighbor Discovery process is resilient to IPv6 unicast addresses being recycled,
because of the use of the "override" flag ("ovr", or "o-bit") in IPv6 Neighbor Advertisements.
In the tshark trace below, a kubernetes pod with IPv6 address 2001:101::2 is trying to ping a pod at 2001:101::3.
However, the previous pod that had been assigned the address 2001:101::3 has just been deleted, and a new pod was brought
up using the same address. After several seconds of ping failure (trying to ping the now-deleted pod), the ping requestor
sends a Neighbor Solicitation for 2001:101::3. The new pod with the this address then responds with a Neighbor Advertisement
with the "ovr" (override) flag set (line 15 in the tshark output) indicating that any Neighbor Discovery cache entries for
this address should be overwritten with the new pods link layer address.

[kube@kube-minion-1 ~]$ sudo tshark -i cbr0
Running as user "root" and group "root". This could be dangerous.
Capturing on 'cbr0'
  1 0.000000000 fe80::858:aff:fef4:6504 -> ff02::2      ICMPv6 70 Router Solicitation from 0a:58:0a:f4:65:04
  2 4.010852825 fe80::858:aff:fef4:6504 -> ff02::2      ICMPv6 70 Router Solicitation from 0a:58:0a:f4:65:04
  3 4.668160112  2001:101::2 -> 2001:101::3  ICMPv6 118 Echo (ping) request id=0x2b00, seq=0, hop limit=0
  4 5.670822295  2001:101::2 -> 2001:101::3  ICMPv6 118 Echo (ping) request id=0x2b00, seq=1, hop limit=0
  5 6.672024902  2001:101::2 -> 2001:101::3  ICMPv6 118 Echo (ping) request id=0x2b00, seq=2, hop limit=0
  6 7.679757238  2001:101::2 -> 2001:101::3  ICMPv6 118 Echo (ping) request id=0x2b00, seq=3, hop limit=0
  7 8.691255786  2001:101::2 -> 2001:101::3  ICMPv6 118 Echo (ping) request id=0x2b00, seq=4, hop limit=0
  8 9.681352136 fe80::858:aff:fef4:6502 -> 2001:101::3  ICMPv6 86 Neighbor Solicitation for 2001:101::3 from 0a:58:0a:f4:65:02
  9 9.692054034  2001:101::2 -> 2001:101::3  ICMPv6 118 Echo (ping) request id=0x2b00, seq=5, hop limit=0
10 10.684291883 fe80::858:aff:fef4:6502 -> 2001:101::3  ICMPv6 86 Neighbor Solicitation for 2001:101::3 from 0a:58:0a:f4:65:02
11 10.694614463  2001:101::2 -> 2001:101::3  ICMPv6 118 Echo (ping) request id=0x2b00, seq=6, hop limit=0
12 11.686498799 fe80::858:aff:fef4:6502 -> 2001:101::3  ICMPv6 86 Neighbor Solicitation for 2001:101::3 from 0a:58:0a:f4:65:02
13 11.706576175  2001:101::2 -> 2001:101::3  ICMPv6 118 Echo (ping) request id=0x2b00, seq=7, hop limit=0
14 12.707311404  2001:101::2 -> ff02::1:ff00:3 ICMPv6 86 Neighbor Solicitation for 2001:101::3 from 0a:58:0a:f4:65:02
15 12.707390366  2001:101::3 -> 2001:101::2  ICMPv6 86 Neighbor Advertisement 2001:101::3 (sol, ovr) is at 0a:58:0a:f4:65:04
16 12.707407921  2001:101::2 -> 2001:101::3  ICMPv6 118 Echo (ping) request id=0x2b00, seq=8, hop limit=0
17 12.707425503  2001:101::3 -> 2001:101::2  ICMPv6 118 Echo (ping) reply id=0x2b00, seq=8, hop limit=0 (request in 16)
18 13.708960301  2001:101::2 -> 2001:101::3  ICMPv6 118 Echo (ping) request id=0x2b00, seq=9, hop limit=0
19 13.709022053  2001:101::3 -> 2001:101::2  ICMPv6 118 Echo (ping) reply id=0x2b00, seq=9, hop limit=0 (request in 18)
20 14.709391763  2001:101::2 -> 2001:101::3  ICMPv6 118 Echo (ping) request id=0x2b00, seq=10, hop limit=0
21 14.709484582  2001:101::3 -> 2001:101::2  ICMPv6 118 Echo (ping) reply id=0x2b00, seq=10, hop limit=0 (request in 20)
22 15.730040594  2001:101::2 -> 2001:101::3  ICMPv6 118 Echo (ping) request id=0x2b00, seq=11, hop limit=0
23 15.730159938  2001:101::3 -> 2001:101::2  ICMPv6 118 Echo (ping) reply id=0x2b00, seq=11, hop limit=0 (request in 22)
^C 24 17.736764505 fe80::858:aff:fef4:6504 -> 2001:101::2  ICMPv6 86 Neighbor Solicitation for 2001:101::2 from 0a:58:0a:f4:65:04
25 17.736888045  2001:101::2 -> fe80::858:aff:fef4:6504 ICMPv6 78 Neighbor Advertisement 2001:101::2 (sol)
25 packets captured
[kube@kube-minion-1 ~]$