IPv6 Neighbor Discovery Protocol on Cisco Router

Hi,
My topo:
[R1]----[R2]
When both router booted up, I first configured R1 interface as 2001::1/64 IPv6, and hasn’t configured R2 yet. But I can see from packet capture that R1 is sending NS and NA both. Without configuring R2, why R1 sent NA? And after that, if I configure R2 with 2001::2/64 interface, I notice the same behaviour. Please find the pcap and interface show o/p. Please let me know the correct behaviour?
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PCAP: https://www.cloudshark.org/captures/623abeaa7dc5
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R1:
ESW1#sh ipv6 int f0/0
FastEthernet0/0 is up, line protocol is up
  IPv6 is enabled, link-local address is FE80::C001:8FFF:FEEF:0
  No Virtual link-local address(es):
  Global unicast address(es):
    2001::1, subnet is 2001::/64
  Joined group address(es):
    FF02::1
    FF02::1:FF00:1
    FF02::1:FFEF:0
  MTU is 1500 bytes
  ICMP error messages limited to one every 100 milliseconds
  ICMP redirects are enabled
  ICMP unreachables are sent
  ND DAD is enabled, number of DAD attempts: 1
  ND reachable time is 30000 milliseconds

=================================================

R2:
ESW2#show ipv6 int f0/0
FastEthernet0/0 is up, line protocol is up
  IPv6 is enabled, link-local address is FE80::C002:8FFF:FEF7:0
  No Virtual link-local address(es):
  Global unicast address(es):
    2001::2, subnet is 2001::/64
  Joined group address(es):
    FF02::1
    FF02::1:FF00:2
    FF02::1:FFF7:0
  MTU is 1500 bytes
  ICMP error messages limited to one every 100 milliseconds
  ICMP redirects are enabled
  ICMP unreachables are sent
  ND DAD is enabled, number of DAD attempts: 1
  ND reachable time is 30000 milliseconds