Gert Doering wrote:
Hi,
On Thu, Aug 27, 2009 at 09:35:54AM +0100, Phil Mayers wrote:
IPv6 emulated the then-state-of-the-art IPX autoconfig mechanisms, and
seems reluctant to admit it's missed out the last decade of operational
knowledge acquired with IPv4.
SLAAC should die the death it so richly deserves (except for link-local)
and DHCPv6 should gain prefix advertisment capability.
SLAAC works *very* well for the things it was made for: zero-conf
environments, with no dedicated DHCP server - as in "home networks" or
"office networks".
Hmm.
It seems to me that there are two types of networks:
1. Not connected to the internet at all i.e. no router etc. - in which
case SLAAC can just allocate link-local addresses
2. A small network with a router - in which case, I fail to see why
the router can't embed a DHCPv6 server just as easily as
SEND/CGA/RFC5006 RA implementation
Basically, I think SLAAC should only ever allocate link-local. I'm fine
with that - it does, as you say, do the job very well, and the ability
to bootstap subnet-local connectivity off link-local makes the next
steps much easier, cleaner and saner.
It's not meant to be used for connecting customer sites to an ISP
network, and it's not overly useful for numbering servers either - but
that doesn't make it "death deserving".
Fair point.
The problem is that there seems to be a zealous effort to shoehorn
everything into SLAAC (e.g. DNS servers) and avoid bringing any "IPv4
mistakes" into IPv6.
But some people seem to think DHCP is a "mistake", and DHCP options a
"mistake" and allocating fixed IPs a "mistake". I cannot share that view.
I think that holds IPv6 back, because a lot of enterprises aren't
willing to be the guinea pigs for an unproven model where potentially
rogue clients generate their own addresses as they please.
I do think that there's nothing SLAAC can do that DHCPv6 can't do, if a
prefix advertisment DHCPv6 option were created. And as I say, I wonder
therefore what the point is - why couldn't these tiny home & office
networks with ADSL just as easily embed a minimal DHCPv6 server, versus
an RFC 5006 implementation?
Ironically we can't use DHCPv6 here even if we wanted to, because it
doesn't work in 6vPE under SXI - I was told it was "harder than it
seemed" and my TAC case was closed as the opened a PER - I think...
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