DHCPv6 PD & Routing Questions

Fri Nov 20 23:36:46 UTC 2015

> On Nov 20, 2015, at 13:35 , Jim Burwell <jimb at jsbc.cc> wrote:
> 
> Hi,
> 
> Have a simple couple of questions here. 
> 
> In my admittedly cursory glances over the DHCPv6 RFCs, I don't see any
> reference to the protocol having any role in managing the routing of
> prefixes it delegates.  Perhaps I missed it, but I somewhat expected the
> omission of this responsibility would be the case.
> 
> My questions are:
> 
> 1) Does the DHCPv6 protocol include any standards/mechanisms/methods for
> managing routes to prefixes it delegates, or does it consider this
> outside of its function?  (I suspect the latter)

Yes and no…

DHCPv6 doesn’t include anything specifically per se, but it does require that
the local router sees the DHCPv6 PD answer in the process of passing it
along to the target, and there’s a pretty obvious expectation that said router
will have to arrange to do the needful in that respect.

> 2) What are the most common ways of managing the routing of delegated
> prefixes in the ISPs routing domain?  Has a standard method/best
> practice emerged yet?  Routing protocols?  IPv6 RAs?

RAs really only apply to subnet local advertisement of routers and
the on-net prefixes in most implementations.

I don’t think any of the various methods of using routing protocols,
static pre-routed blocks from which PDs are delegated, etc.  could
necessarily be called “standardized”, but there are probably a few
that are more popular than most of the others.

Unfortunately, PD is really still in its infancy in terms of development
and real running code for complete implementations throughout any
sort of site hierarchy.

Owen