Router ID on IPv6-Only

Bjørn Mork bjorn at
Thu Sep 8 06:54:52 UTC 2022

Crist Clark <cjc+nanog at> writes:

> During some IPv6 numbering discussions at work today, someone had a
> question that I hadn't really considered before. How to choose 32-bit
> router IDs for IPv6-only routers.

Why would you do it differently than for dual-stack routers, except that
you skip the step where you configure the ID as a loopback address?

Of course you don't have care about routing the 32bit IDs anymore
either.  But that doesn't really change anything either.  Except that
can skip even more configuration.

It's obviously possible to connect the ID to some IPv6 address on the
router, as long as you understand the structure of that allocation and
can select the right bits or hash to make it unique.  But if you don't
do that for dual-stack today, then why care?  Or if you do it for
dual-stack, then what changed?


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