ipv6 addressing...

wendell said it, so i guess it's an okay practice... not sure about you, but i like to easily identify the links i build...  i'm just funny that way...

To discover which routers use which link local addresses, and make it easier to work with link local addresses, you have a couple of options. First, you can set the MAC address of each LAN interface to something noticeable. For Example 17-2, the routers each used a recognizable MAC: R1 used 0200.1111.1111, R2 used 0200.2222.2222, and so on. Alternatively, you can just configure the link local address with the ipv6 address command, using the link-local keyword at the end, and make each link local address be more
recognizable.

this stuff is tough enough... control the things you can...

note on the below diagram all the endpoints, have endpoints...

that deserves a hot chick smile...