IPv6 Advanced

How IPv6 hosts actually get configured and discover neighbours — and how IPv4 and IPv6 coexist.

// SLAAC, NDP & EUI-64

SLAAC: host self-configures from the RA prefix + interface ID
NDP replaces ARP — runs over ICMPv6 with multicast
EUI-64: split the MAC, insert FFFE, flip the 7th bit
DHCPv6 can be stateful (addresses) or stateless (options)
No broadcast — uses multicast and anycast instead

// NDP messages (ICMPv6)

RS	Router Solicitation
RA	Router Advertisement
NS	Neighbor Solicitation
NA	Neighbor Advertisement

// transition mechanisms

Dual stack	Run IPv4 + IPv6 together (preferred)
Tunneling	6in4, 6to4, Teredo, ISATAP, GRE
Translation	SIIT / NAT-PT / NAT64+DNS64 map v6 ↔ v4

// multicast scopes (ffXs::)

1	Interface-local
2	Link-local
4	Admin-local
5	Site-local
8	Organization-local
E	Global

enable ipv6 · cisco ios

ipv6 unicast-routing
!
interface GigabitEthernet0/0
 ipv6 address 2001:db8:0:1::1/64
 ipv6 address fe80::1 link-local
 ipv6 enable
 ipv6 nd ra suppress all

verify

show ipv6 interface brief
show ipv6 route
show ipv6 neighbors
ping ipv6 2001:db8:0:1::2