Re: Splitting /64 over Multiple Gateway Interfaces in rtadvd

Ben Goren <[email protected]> wrote:

> That still leaves 281,474,976,710,656 /48s, assuming that's the only 
> way you sliced it.
> So, nowhere near as many /48s as I had thought, but still enough to not 
> start worrying.

Indeed.

> But...that also means that each /48 comes with 2**80 addresses, no? 

Sort of.
Ben, you really should have looked at an introduction to IPv6 before
jumping into this thread.  Typically, an IPv6 unicast address breaks
down like this:

    |        48 bits          |  16 bits  |       64 bits              |
    +-------------------------+-----------+----------------------------+
    | global routing prefix   | subnet ID |       interface ID         |
    +-------------------------+-----------+----------------------------+

This gives you plenty of /64 subnets and leaves 2**64 host addresses
in each, which seems a bit excessive, until you realize that the
idea isn't to fill up this address space, but to allow IPv6 stateless
address autoconfiguration, which for Ethernet devices uses addresses
derived from the interface MAC address.

For my home network, I have a global prefix 2001:6f8:124a::/48, and
I have assigned two subnets 2001:6f8:124a:0::/64 (wired) and
2001:6f8:124a:1::/64 (wireless) so far, with a variety of hosts.
And, to get back to the topic indicated in the subject line, on the
gateway I simply run rtadvd(8) on both interfaces with no configuration
file.

-- 
Christian "naddy" Weisgerber                          [email protected]