v6 peering at PAIX/Palo Alto

[Gert Doering]

hi,

On Tue, Aug 29, 2006 at 10:58:29AM -0400, Joe Abley wrote:
> Switch and Data recently started distributing addresses assigned out  
> of 2001:540:d::/48 for use in v6 peering on their Bay Area fabric  
> (exposed at 529 Bryant/Palo Alto, 200 Paul/San Francisco, etc),  
> replacing the 6bone prefix that had been in use there for a long time.
> 
> Trouble is S&D didn't specify a prefix length when they told people  
> their addresses. I know some people who have assumed a /64. S&D  
> themselves insist that the correct prefix length is a /48.

I'd throw RFC 4291 at them, but it doesn't really say "/64 is what
you want to use" for anything that's not EUI-64 based.

> Seems to me that if I was S&D, I'd be carving one /64 out of that /48  
> for each exchange point fabric I operated. Perhaps they have other  
> plans, though (or aspirations to attract more than 2^64 peers to  
> their Bay Area fabric :-)
> 
> So anyway, just interested -- how many people here assumed that the  
> prefix length was /64?

Well, that's "the current best practice" on multi-access networks...

> What operational damage might result from a mixture of routers  
> configured with their PAIX address variously in a /48 or a /64? Will  
> it make any practical difference to anything?

I'd expect neighbour solicitation messages for addresses in the /48,
but not in the /64, which might cause problems - or maybe not, 
depending on implementations.

People leaking the /64 into BGP will cause funnies to ISPs that have
a /48 configured (more-specific wins!) and have no filters.

Reachability for *other* /64s in the /48 will be funny.

Morale: "bad idea".

Gert Doering
        -- NetMaster
-- 
Total number of prefixes smaller than registry allocations:  94488

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