Re: Ideas for IPv6 BGP and tunnelling

[Adrian Kennard <[e-mail]>]

Brian E Carpenter wrote:
> Ole,
> 
> On 2009-04-24 01:02, Ole Troan wrote:
>>> But I fear there so far the idea hasn't gotten much traction. In fact, the
>>> RFC4798 predecessor documents [1] included ability to set up tunnels over
>>> GRE and similar non-MPLS encapsulations.  This was explicitly _removed_
>>> because the solution was targeted at MPLS networks, not as a general purpose
>>> BGP-signalled tunneling mechanism.
>>>
>>> [1] take a look at e.g:
>>> http://tools.ietf.org/html/draft-ooms-v6ops-bgp-tunnel-00
>> I thought 6PE and BGP tunnelling got split into separate documents?
>> obviously my memory isn't serving me right.
> 
> http://tools.ietf.org/id/draft-ietf-ngtrans-bgp-tunnel-04.txt
> (thankyou Google)
> 
> I don't recall why that never became an RFC.

That is exactly what I am talking about.

It uses "The IPv4-mapped IPv6 address is defined in [V6ADDR]" as the
next hop. That means ::FFFF:x.x.x.x as an IPv4 address.

What is not clear to me is what this the best practice and workable IPv6
next hop to specify. Seems to me it could be:-

::x.x.x.x
::FFFF:x.x.x.x
2002:xxxx:xxxx::

The latter seems to express that we want to use simple protocol 41 IPv6
over IPv4 tunnelling. The first two seem to me to just indicate an IPv4
address as the next hop without saying how the traffic is to be sent to
it (e.g. GRE, protocol 41, whatever).

Do we need an RFC on this?

FYI, I'll make our routers understand any of the above as a next hop to
send over protocol 41 when received, but need to know what I should used
when generating this as a next hop to send.