AT&T UVERSE Native IPv6, a HOWTO

Owen DeLong owen at delong.com
Tue Dec 3 01:27:36 UTC 2013


On Dec 2, 2013, at 17:20 , Ricky Beam <jfbeam at gmail.com> wrote:

> On Mon, 02 Dec 2013 19:16:27 -0500, Mark Andrews <marka at isc.org> wrote:
>> So you go from one extreme to another.  One lan to one lan-per-device.
> 
> No.  I'm complaning about how the automatic solution to segmenting the home ("homenet") doesn't put any thought into it at all, and puts everything in it's own network.  I cannot believe anyone would ever put that on paper, but they did.

That isn't how I read any of the drafts that I've seen, so I'm not sure where you get this.

> 
> Anyway. If you want your home segmented, then a human being needs to take a few minutes to think about it and then configure the network (physical and logical) and devices accordingly.  That's a very complex problem to solve via AutoMagic Technology(TM) (hence the homenet approach.)

Nope... 

You plug in the top level router, then start plugging stuff into it. Switches, other nodes, other routers. In the case of other routers, then you plug stuff into them. Lather, rinse, repeat. Wherever you have a router, you have a boundary between links.

Simple as that.

It's actually not complex for technology to figure out a hierarchy of routers and allocate prefixes to them, but it doesn't work out very well if you only have a few bits to play with and have to dense-pack the allocations. It basically boils down to spanning tree on steroids if you have a wide enough bit field to handle the breadth and depth of the hierarchy.

> 
>>> isolated networks... wifi, guest wifi, lan-1, lan-2, lan-3, lan-4 (for 4
>> 
>> Each of which needs a /64.  16 subnets is incredibly small.
> 
> In this example, it takes 6. Six.  16 is almost 3x that, and thus, plenty big enough.

Depends on how they are connected and how you want the automation to work. Do you want room to grow at the various levels of the hierarchy? What happens when someone plugs a new router in between LAN2 and LAN3 that also connects LANS 5, 6, 7, and 8?

> As we're getting our prefex via DHCPv6-PD, it's not hard to ask for a larger prefix when needed. (of course, every idiot is going to ask for the largest prefix possible, and then only use 3 /64's)

So what? If the largest prefix possible is a /48, then every idiot has more than enough space to do what they need and there's no harm to the ISP or anyone else. Sounds like an ideal solution to me.

>> The only thing stifling this is ISP's being measly with how they
>> hand out address blocks.  If ISPs all hand out /60's this sort of
>> development just won't happen and it will be entirely the ISP's
>> fault for being so short sighted.
> 
> They could be do much worse... if you throw out SLAAC, your network(s) can be smaller than /64.  I don't want to give them any ideas, but Uverse could use their monopoly on routers to make your lan a DHCP only /120.

I think if they did that, they'd do more to evaporate Uverse customers than to change the world of IPv6 routing at this point.

Owen




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