Subject: draft-templlin-6man-aeroaddr

From: Michael Richardson <[email-masked]>
Date: Mon, 05 Jun 2017 17:44:02 -0400

Templin, Fred L <[email-masked]> wrote:
    > Hi, one example where /64 is very useful is for the construction of AERO
    > addresses as documented in:

    > https://datatracker.ietf.org/doc/draft-templin-6man-aeroaddr/

    > The draft is very short, but here are the main thrusts:

    > "An AERO address is an IPv6 link-local address with an interface
    > identifier based on a prefix that has been delegated to a node for
    > its own exclusive use.  AERO addresses begin with the prefix
    > fe80::/64 and include in the interface identifier (i.e., the lower
    > bits) a 64-bit prefix taken from one of the node's delegated
    > prefixes.  For example, if the node receives the IPv6 prefix:

    > 2001:db8:1000:2000::/64

    > it constructs its corresponding AERO addresses as:

    > fe80::2001:db8:1000:2000"

Interesting idea. I'm not quite sure I see the win, but I don't see any
downside either.

PPP links just make up random stuff, with the option that they
can keep it around across reboots.  Or is the point to offload that state
into the network?

Is your uplink is more ethernet-like? You don't want to use the old-style
EUI-64 (maybe you don't have one?), and the stable-private address doesn't
work for you?

It's not clear to me if this behaviour even needs to be standardized...
It doesn't seem to have any operational affects outside the node in question.

--
Michael Richardson <[email-masked]>, Sandelman Software Works
 -= IPv6 IoT consulting =-

---

From: "Templin, Fred L" <[email-masked]>
Date: Mon, 5 Jun 2017 22:44:15 +0000

Hi Michael,

> -----Original Message-----
> From: Michael Richardson [mailto:[email-masked]]
> Sent: Monday, June 05, 2017 2:44 PM
> To: Templin, Fred L <[email-masked]>
> Cc: 6man <[email-masked]>
> Subject: draft-templlin-6man-aeroaddr
> 
> 

I am using it on NBMA links where a node first obtains a delegated
prefix then next statelessly constructs an AERO address for itself.
The AERO address then statelessly links IPv6 ND with IPv6 forwarding;
if there is a neighbor cache entry with an AERO address that matches
the packet's IPv6 destination address then there is no need to also
look up the destination in the IPv6 forwarding table.

> EUI-64 (maybe you don't have one?), and the stable-private address doesn't

It gives a way for a node that receives a prefix delegation to statelessly
configure a unique IPv6 link-local address for itself that does not need
to be tested with DAD. And, it can be assigned to any of the node's
interfaces that honor the address format even if the same address
would be assigned to multiple interfaces (since the scope is link-local).

> It doesn't seem to have any operational affects outside the node in question.

If you want to run a link where every node on the link plays by the
same rules it might be better to have it written down somewhere.

Thanks - Fred
[email-masked]

---

From: Michael Richardson <[email-masked]>
Date: Mon, 05 Jun 2017 21:58:35 -0400

> look up the destination in the IPv6 forwarding table.

So you are taking advantage of the mapping to implicitely do the routing?

What kind of NBMA link is it?
This could be useful for the ANIMA ACP, which is a mesh of IPsec (normally)
over LL tunnels.

---

From: "Templin, Fred L" <[email-masked]>
Date: Tue, 6 Jun 2017 14:53:05 +0000

Hi Michael,

> Sent: Monday, June 05, 2017 6:59 PM
> Subject: Re: draft-templlin-6man-aeroaddr
> 
> 

Yes, since the routing information is available from the link-local address
why not use it?

> What kind of NBMA link is it?

It is an NBMA link based on encapsulation without explicit tunnels. IP is
seen as the link-layer for IP, and an ingress node can send encapsulated
packets to any among possibly man egress nodes. The ingress node
keeps a neighbor cache entry for each egress, indexed by the egress'
AERO address.

That said, this may be useful for any NBMA link type, and not just
multipoint tunnels.

> This could be useful for the ANIMA ACP, which is a mesh of IPsec (normally)

I think there may be many other uses - thanks for pointing this one out.
Please feel free to forward a pointer to the document to anyone in that
community who may be interested.

Thanks - Fred