IPv6 route annoucement

Mark Andrews marka at isc.org
Thu Aug 7 21:57:12 UTC 2014

In message <bdc20a2a2ce17f668939ac7477502f1b at mail.gmail.com>, John York writes:
> Hoping to not start a war...
> We (a multi-homed end-user site) are finally getting IPv6-enabled Internet
> connectivity from one of our ISPs. In conversations regarding our BGP
> config, the ISP has balked at allowing us to advertise our ARIN-assigned
> /44, saying things like, "do you know how many addresses that is!!??"

Your ISP needs a IPv6 clue bat to be applied.  Your ISP needs to
learn that a /44 is 16 sites.  It is also the next nibble boundry
above a /48.  The ISP shouldn't care about the number of addresses.
You have justified your allocation based on the fact you are
multi-homed and presumably the number of sites.

The ISP appears to be wildly off base.

> Am I way off base in thinking this network size is not out of the norm? I
> know it's a lot of addresses (19 octillion-something?), but that
> assignment was based on the same criteria that got us a /22 in v4 space.
> Should accepting a /44 in v6 not be equivalent, policy-wise, to accepting
> a /22 in v4?

Address allocation in IPv6 is, or should be, number-of-sites based
in IPv6 for end customers with a site gettting a /48.  The exception
is when a site needs more that 2^16 /64 subnets at a site which
needs justification.  For ISPs it is number-of-customer-sites (1
home == 1 site == 1 customer, commercial customers may have more
than one site and need a bigger allocation) based with tuning for
number-of-pops along with the customer allocation size (a /48 per
customer site is reasonable though some ISPs do /56).

IPv4 prefix size should have no bearing on the size of the IPv6
prefix for end customers.  In IPv4 you count hosts.  In IPv6 you
count sites.  This is as different as comparing apples and oranges.

Just because you need a /22 in IPv4 doesn't mean you need a /44 in
IPv6.  You should be requesting address space based on the number
of sites one has.


> Thanks,
> John
> --
> John York
> Information Technology | Network Administrator
> Phone:
> 615-399-7000 x:333
> Griffin Technology
> 2030 Lindell Avenue Nashville, TN  37203 USA
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org

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