To stay updated what’s happening in the network industry it doesn’t hurt to
read some RFCs and IETF drafts. Here are two I recommend that you read.
It describes different ways of tunneling v6. Could be very useful for a
CCIE candidate as well if you want to experiment with deploying v6 and can’t
dual stack yet.
This one describes how IP has evolved and some of the “networking truths” that
may not be true.
I recommend you read both of them.