> On Nov 25, 2015, at 15:59 , Mark Andrews <ma...@isc.org> wrote: > > > In message > <CAMWxDfrh+O=SPZwPmAZhYnvAEeK2eMFw3CD0qf34Fkbb=-s...@mail.gmail.com>, Brian > Knight writes: >> On Tue, Nov 24, 2015 at 6:34 PM, Baldur Norddahl >> <baldur.nordd...@gmail.com> wrote: >>> >>> DHCPv6-PD allows multiple PD requests. But did anyone actually implement >>> that? I am not aware of any device that will hand out sub delegations on >>> one interface, notice that it is out of address space and then go request >>> more space from the upstream router (*). >>> >>> DHCPv6-PD allows size hints, but it is often ignored. Also there is no >>> guidance for what prefix sizes you should ask for. Many CPEs will ask for >>> /48. If you got a /48 you will give out that /48 and then not honor any >>> further requests, because only one /48 per site is allowed. If you are an >>> ISP that gives out /48 and your customers CPE asks for a /56 you will still >>> ignore his size hint and give him /48. >> >> Or, worse, the ISP's DHCPv6 server honors the new request and issues >> the larger prefix, but refuses to route it. Ran into that myself when >> I replaced my home CPE router, and changed the prefix hint to ask for >> a /60 block (expanded from /64) at the same time. That made for a >> frustrating few days without IPv6 service, waiting for my original >> delegation to expire. (Tech support, of course, had no clue and >> blamed my router.) >> >> In retrospect I should have perhaps had my original CPE generate a >> DHCP release message for that prefix before disconnecting it. But I >> won't be the last person to fail to generate that. >> >> -Brian > > Well the requesting router could announce the route. ISC's client > has hooks that allow this to be done. That is, after all, how > routing is designed to work. The DHCP server usually is sitting > in a data center on the other side of the country with zero ability > to inject approptiate routes. >
Are you really suggesting that a residential ISP accept routes advertised from their customer’s CPE? Really? That’s about the most ridiculous thing I’ve heard on NANOG in a long time and that’s saying something. > The DHCP relay could also have injected routes but that is a second > class solution. Maybe, but in an ISP/Customer PD environment, it’s certainly preferable to what you consider a “first class” solution. Owen
