IPv6 has been "the new thing" for so long that engineers sometimes forget it is now the default address family on cloud platforms, mobile networks, and most modern ISPs. This lab teaches the structure of an IPv6 address: link-local, global unicast, the EUI-64 trick that derives a host portion from the interface MAC, and how Cisco IOS shows it all. You will work on R1, R2, and R3 from the base topology - all three routers get IPv6 routing enabled and addressed end to end. Most addresses are assigned manually (so the next lab, nf-08, can build static routes on top of them); R2's LAN interface additionally gets an EUI-64 address so you can watch the algorithm work on a real MAC.
What you will learn
- The structure of a 128-bit IPv6 address and how prefix length works (no masks; just a /N)
- The two addresses every IPv6-enabled interface has: link-local (FE80::/10) and at least one global unicast
- The EUI-64 algorithm for auto-deriving the host portion from a MAC address - and why operators love it and hate it
- The difference between configuring an address manually and with the
eui-64keyword (and that one interface can carry both at once) - The neighbor table (the IPv6 equivalent of ARP) and how it populates
What this lab does NOT cover
- SLAAC (Stateless Address Auto-Configuration) on hosts. Touched briefly; covered fully on the OSPF/IPv6 dual-stack work in the IPv6 pillar.
- DHCPv6. Out of scope for CCNA address fundamentals.
- IPv6 static routes. Next lab: nf-08.
The IPv6 addressing plan
This is the IPv6 overlay for the base topology. It mirrors the IPv4 scheme you already know: the 10.20.0.0/24 LAN becomes 2001:db8:20::/64, the 10.30.30.0/30 transit becomes 2001:db8:30::/64, and the 10.255.0.x loopbacks become 2001:db8:255::x/128.
Why manual everywhere except one interface? Infrastructure addressing needs to be predictable - the static routes in nf-08 point at these exact addresses, and in production you want transit links and loopbacks to survive a hardware swap (which changes the MAC, and would change every EUI-64 address with it). R2's Ethernet0/0 gets a second, EUI-64-derived global purely so you can see the algorithm in action.
