IPv6 allocations, deaggregation, etc.

Joel Jaeggli joelja at bogus.com
Tue Dec 22 23:16:38 CST 2009

George Bonser wrote:
> We have decided to initiate the process of becoming IPv6 capable.  We
> have requested and received a block of addresses which, after reading
> some of the discussion here, I fear may be too small to suit our needs
> (a /48).  To better understand how to proceed and in an attempt to get
> it right (or close to right) the first time, I am soliciting opinions
> and comments from other network operators.

Given you topology your direct assignment request should properly
reflect the number of sites you expect to need to need to serve.  At a
/48 per site it starts to look rational.

> It appears from earlier discussions on this list that while many
> networks will not filter a /48 announcement in their routing tables,
> others will.  We have data centers and offices in three regions of the
> globe; North America, Europe, and Asia/Pacific.  We are also multihomed
> as well as having some direct peering.  I can break my /48 into /56 nets
> for each facility.  My thought process here being that if I have the
> same transit providers at all sites, I can announce the /48 from my
> primary location and that would get announced by the transit provider.
> They would also accept my more specific routes but not announce them
> outside of their AS.  So traffic originating outside of my transit
> provider would flow toward them following the /48 and they then move the
> traffic to the final destination based on the more specific and in the
> case the traffic has no more specific route, hand the traffic to my main
> location for me to sort out or just black hole it.  There are two
> problems with this approach.  1: We are unreachable from anyone
> filtering a /48 and 2: I could see a situation where traffic crosses the
> Pacific, is handed to my transit provider, and then crosses the Pacific
> again to get to the destination resulting in poor performance.
> So it now seems to me that maybe a larger block might be the best answer
> but being an "end user" the policies seem pretty restrictive on getting
> a /32 though I might qualify for several /48 blocks (at least one in
> each registry region).  So how does one reconcile having a diverse,
> multihomed organization on several continents while at the same time
> trying to do the right thing, not requesting more resources than we
> need, and trying to be friendly to the various networks' operations by
> advertizing only what we need to?  Is it unreasonable to get separate
> /48 blocks for operations in Europe, North America, and Asia or possibly
> two for Asia (one in China and one for Asia outside of China)?  While
> that still won't help us with connectivity from networks filtering
> /48's, it might relieve much of the back and forth transit across oceans
> to get traffic originating from and destined for the same continent to
> stay there.  I don't have a problem with regional backhaul tying an
> office /56 to a data center announcing a /48 and using that data center
> as a communications hub for the region.  It also assumes a transit
> provider I am paying to haul my traffic will take "more specifics" for
> internal use even if they aren't advertizing them.
> I am just trying to minimize the stupidity and barriers to scale on my
> side of the equation.

More information about the NANOG mailing list