How about some actual technical complaints about shim6? good question. to give such discussion a base, could you point us to the documents which describe how to deploy it in the two most common situation operators see o a large multi-homed enterprise customer There are no documents describing deployment. Probably there should be.
The general approach is presumably well-known (for those for whom it is not, go browse around <http://www.ietf.org/html.charters/shim6- charter.html>, and perhaps in particular <http://www.ietf.org/ internet-drafts/draft-ietf-shim6-proto-03.txt>.
Deployment in an enterprise is a matter of:
(a) deploying hosts with shim6-capable stacks within the enterprise;
(b) arranging for those hosts to receive addresses in each PA assignment made by each transit provider (multiple PA addresses per interface), e.g. using dhcp6;
(c) optionally, perhaps, installing shim6 middleware at some suitable place between host and border in order to impose site policy or modulate locator selection by the hosts.
and this last will handle the normal site border (and these days intra-site, e.g., departmental, borders) issues such as o dns within the enterprise is isolated from that of outside o firewalls, algs, and sometimes nats o security policy in general o load balancing between upstreams o ... i.e, what handles the impedance mismatch between the goal, which is *site* multi-homing, and the tool, which is *host* multihoming? and how does it handle it, how is it managed, ...?
You will note I have glossed over several hundred minor details (and several hundred more not-so-minor ones). The protocols are not yet published; there is no known implementation.
possibly this contributes to the sceptisim with which this is viewed?
o a small to medium multi-homed tier-n isp A small-to-medium, multi-homed, tier-n ISP can get PI space from their RIR, and don't need to worry about shim6 at all. Ditto larger ISPs, up to and including the largest.
as it is not yet clear if small isps can get pi space, and the issue of multi-homing is central to the discussion of this issue, and routing table growth is another vector here, perhaps this needs to be explored a bit more. randy