IPv6 Advertisements

What is the smallest IPv6 advertisement that organizations
are going to 
honour- are we still looking at a minimum of a /48?

-Don

On Mon, 28 May 2007, Donald Stahl wrote:
> What is the smallest IPv6 advertisement that
organizations are going to 
> honour- are we still looking at a minimum of a /48?

Anything more specific than /32 is going to be filtered at
some 
portion of the ISPs whether for the good or bad.  There are
some 
subsets of the v6 address space that have a higher chance of
/48 
working (for some definition of 'working') than other parts
of the 
address space, though.

-- 
Pekka Savola                 "You each name yourselves
king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash
of Kings

On Tue, May 29, 2007 at 08:45:38AM +0300, Pekka Savola
wrote:
> 
> On Mon, 28 May 2007, Donald Stahl wrote:
> >What is the smallest IPv6 advertisement that
organizations are going to 
> >honour- are we still looking at a minimum of a
/48?
> 
> Anything more specific than /32 is going to be filtered
at some 
> portion of the ISPs whether for the good or bad.  There
are some 
> subsets of the v6 address space that have a higher
chance of /48 
> working (for some definition of 'working') than other
parts of the 
> address space, though.
> 
	perhaps you might better phrase this as; " Anything
more specific
	than a /3 is going to be filtered at some portion of the
ISPS whether
	for the good or bad."

	just because you have a prefix of (any) size, does not
assure 
	that everyone will route it.

--bill

> Anything more specific than /32 is going to be filtered
at some portion of 
> the ISPs whether for the good or bad.  There are some
subsets of the v6 
> address space that have a higher chance of /48 working
(for some definition 
> of 'working') than other parts of the address space,
though.
More specific advertisements always stand a chance of being
blocked. I was 
more interested in whether or not people know of places
where they are 
actively being blocked and why.

That said- ARIN is handing out /48's- should we be blocking
validly 
assigned networks?

-Don

On Tue, 29 May 2007, Donald Stahl wrote:


> That said- ARIN is handing out /48's- should we be
blocking validly
> assigned networks?

your network might have to to protect it's valuable routing
slots. There
are places in the v4 world where /24's are not carried
either. So, as Bill
said just cause you get an allocation doesn't mean you can
assure
routability of it everywhere.

>> That said- ARIN is handing out /48's- should we be
blocking validly
>> assigned networks?
>
> your network might have to to protect it's valuable
routing slots. There
> are places in the v4 world where /24's are not carried
either. So, as Bill
> said just cause you get an allocation doesn't mean you
can assure
> routability of it everywhere.
I understand the problems but I think there are clear cut
cases where 
/48's make sense- a large scale anycast DNS provider would
seem to be a 
good candidate for a /48 and I would hope it would get
routed. Then again 
that might be the only sensible reason...

-Don

On Tue, 29 May 2007, Donald Stahl wrote:

> >> That said- ARIN is handing out /48's- should
we be blocking validly
> >> assigned networks?
> >
> > your network might have to to protect it's
valuable routing slots. There
> > are places in the v4 world where /24's are not
carried either. So, as Bill
> > said just cause you get an allocation doesn't mean
you can assure
> > routability of it everywhere.
> I understand the problems but I think there are clear
cut cases where
> /48's make sense- a large scale anycast DNS provider
would seem to be a
> good candidate for a /48 and I would hope it would get
routed. Then again
> that might be the only sensible reason...

vixie had a fun discussion about anycast and dns...
something about him
being sad/sorry about making everyone have to carry a /24
for f-root
everywhere. I think there is a list of 'golden prefixes' or
something,
normally this is where Jeroen Masseur jumps in with GRH data
and
pointers.

-Chris

> vixie had a fun discussion about anycast and dns...
something about him
> being sad/sorry about making everyone have to carry a
/24 for f-root
> everywhere.
Whether it's a /24 for f-root or a /20 doesn't really make a
difference- 
it's a routing table entry either way- and why waste
addresses.

I think there are a few services where these sorts of
exceptions make 
sense and f-root is certainly one of them.

-Don

Chris L. Morrow wrote:
[..]
> vixie had a fun discussion about anycast and dns...
something about him
> being sad/sorry about making everyone have to carry a
/24 for f-root
> everywhere. I think there is a list of 'golden
prefixes' or something,
> normally this is where Jeroen Massar jumps in with GRH
data and
> pointers.

*see cue* 

3 years ago I did a presentation about that, see
http://www.sixxs.
net/presentations/ and then "IPv6 Golden
Networks"
for various formats, it is more or less still correct
actually, but
some things might have changed.

The "best" way IMHO to figure out what prefixes
you should be carrying
and what you are missing out on is to make sure you at least
receive
all the allocated blocks.

The lucky folks who are providing a BGP feed to GRH can
simply do that
by checking that here: http://www.sixxs.
net/tools/grh/dfp/
Everybody else can of course either signup or do it
manually.
Every prefix in DFP shows how well connected they are at
least per
BGP, and we assume that reachability by BGP means that you
can shove
packets over a link. Of course this does not show if the
actual link
works vice-versa, or if it is a dsl link in the middle or
not ;)

Should I make an explicit "Golden IPv6 Networks"
list available again?
For IPv4 that was moreover done for dampening reasons, I
don't know if
that is still needed. In effect any Golden network is more
the network
that is most needed by your customers anyway, as such, the
full list
is more accurate.

As for folks wanting "IPv6 Google", http://www.google.com
.sixxs.org
and then you even get the Dutch version, which is quite
liberal 
Any <site>.sixxs.org or <sixxs>.ipv6.sixxs.org
allos you to access
that <site> over IPv6. Using
<sixxs>.ipv4.sixxs.org one can access
IPv6 sites when on IPv4 (which I used for some time when I
didn't have
IPv6 connectivity at work due to firewalls which didn't
work, but now
they do . Of course
see http://ipv6gate.sixxs.net for more details.

Greets,
 Jeroen

On Tue, 29 May 2007 15:08:34 +0000 (GMT)
"Chris L. Morrow" <christopher.morrowverizonbusiness.com> wrote:

> vixie had a fun discussion about anycast and dns...
something about him
> being sad/sorry about making everyone have to carry a
/24 for f-root
> everywhere. I think there is a list of 'golden
prefixes' or something,
> normally this is where Jeroen Masseur jumps in with GRH
data and
> pointers.

In lieu of missing protections for route hijacking there are
arguments
to be made for announcing more specifics.  As will there be
arguments
over where that line should be drawn and who gets to draw
it.  

John